[Federal Register Volume 81, Number 218 (Thursday, November 10, 2016)]
[Rules and Regulations]
[Pages 79261-79348]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-26211]


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DEPARTMENT OF ENERGY

10 CFR Parts 429, 430, and 431

[Docket No. EERE-2014-BT-TP-0008]
RIN 1904-AD18


Energy Conservation Program for Certain Commercial and Industrial 
Equipment: Test Procedure for Commercial Water Heating Equipment

AGENCY: Office of Energy Efficiency and Renewable Energy, Department of 
Energy.

ACTION: Final rule.

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SUMMARY: On May 9, 2016, the U.S. Department of Energy (DOE) published 
a notice of proposed rulemaking (NOPR) to amend its test procedures for 
commercial water heaters, unfired hot water storage tanks, and hot 
water supply boilers (henceforth, ``commercial water heating (CWH) 
equipment''). That proposed rulemaking serves as the basis for this 
final rule. Specifically, this final rule incorporates by reference the 
most recent versions of relevant industry standards; modifies the 
existing test methods for certain classes of CWH equipment; establishes 
new test procedures for determining the

[[Page 79262]]

efficiency of commercial heat pump water heaters and standby loss for 
instantaneous water heaters and hot water supply boilers; clarifies 
test set-up and settings for various classes of CWH equipment; revises 
the certification requirements for CWH equipment; and establishes 
associated definitions.

DATES: The effective date of this rule is December 12, 2016. The final 
rule changes will be mandatory for representations related to energy 
efficiency or energy use starting November 6, 2017. The incorporation 
by reference of certain publications listed in this rule is approved by 
the Director of the Federal Register on December 12, 2016.

ADDRESSES: The docket, which includes Federal Register notices, public 
meeting attendee lists and transcripts, comments, and other supporting 
documents/materials, is available for review at www.regulations.gov. 
All documents in the docket are listed in the www.regulations.gov 
index. However, not all documents listed in the index may be publicly 
available, such as those containing information that is exempt from 
public disclosure.
    A link to the docket Web page can be found at: https://www.regulations.gov/docket?D=EERE-2014-BT-TP-0008. This Web page 
contains a link to the docket for this rulemaking on the 
www.regulations.gov site. The docket Web page contains simple 
instructions on how to access all documents, including public comments, 
in the docket.
    For further information on how to review the docket, contact the 
Appliance and Equipment Standards Program staff at (202) 586-6636 or by 
email: CommWaterHeatingEquip2014TP0008@;ee.doe.gov.

FOR FURTHER INFORMATION CONTACT: 
    Ms. Ashley Armstrong, U.S. Department of Energy, Office of Energy 
Efficiency and Renewable Energy, Building Technologies Office, EE-5B, 
1000 Independence Avenue SW., Washington, DC 20585-0121. Telephone: 
(202) 586-6590. Email: ee.doe.gov">Ashley.Armstrong@ee.doe.gov.
    Mr. Eric Stas or Ms. Jennifer Tiedeman, U.S. Department of Energy, 
Office of the General Counsel, GC-33, 1000 Independence Avenue SW., 
Washington, DC 20585-0121. Telephone: (202) 586-9507 or (202) 287-6111. 
Email: [email protected] or [email protected].

SUPPLEMENTARY INFORMATION: This final rule incorporates by reference 
the following industry standards into part 431:
    (1) American National Standards Institute, (ANSI) Standard 
Z21.10.3-2015/Canadian Standards Association (CSA) Standard 4.3-2015, 
``Gas-fired water heaters, volume III, storage water heaters with input 
ratings above 75,000 Btu per hour, circulating and instantaneous,'' 
ANSI approved on October 5, 2015, Annex E (normative) Efficiency test 
procedures--E.1 ``Method of test for measuring thermal efficiency,'' 
Paragraph c, ``Vent requirements'' and Paragraph f, ``Installation of 
temperature sensing means'';
    (2) American Society of Heating, Refrigeration and Air-Conditioning 
Engineers, ANSI/ASHRAE Standard 118.1-2012, ANSI approved on October 
27, 2012, ``Method of Testing for Rating Commercial Gas, Electric, and 
Oil Service Water-Heating Equipment''; Section 3 ``Definition and 
Symbols,'' Section 4 ``Classifications by Mode of Operation,'' Section 
6 ``Instruments,'' Section 7 ``Apparatus,'' Section 8 ``Methods of 
Testing,'' Section 9 ``Test Procedures,'' and Section 10 ``Calculation 
of Results'';
    (3) ASTM International (ASTM) C177-13, ``Standard Test Method for 
Steady-State Heat Flux Measurements and Thermal Transmission Properties 
by Means of the Guarded-Hot-Plate Apparatus,'' approved September 15, 
2013;
    (4) ASTM C518-15, ``Standard Test Method for Steady-State Thermal 
Transmission Properties by Means of the Heat Flow Meter Apparatus,'' 
approved September 1, 2015; and
    (5) ASTM D2156-09 (Reapproved 2013), ``Standard Test Method for 
Smoke Density in Flue Gases from Burning Distillate Fuels,'' approved 
October 1, 2013.
    Copies of ANSI Z21.10.3-2015/CSA 4.3-2015 and ANSI/ASHRAE 118.1-
2012 can be obtained from the American National Standards Institute, 25 
W. 43rd Street, 4th Floor, New York, NY 10036, (212) 642-4800, or by 
going to http://webstore.ansi.org/.
    Copies of ASTM C177-13, ASTM C518-15, and ASTM D2156-09 can be 
obtained from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, 
West Conshohocken, PA 19428-2959, (610) 832-9585, or by going to http://www.astm.org/Standard/index.html.
    See section IV.N of this final rule for further discussion of these 
standards.

Table of Contents

I. Authority and Background
II. Synopsis of the Final Rule
III. Discussion
    A. Updated Industry Test Methods
    1. ANSI Z21.10.3 Testing Standard
    2. ASTM Standard Test Method D2156 and Smoke Spot Test
    3. ASTM Test Standards C177 and C518
    B. Ambient Test Conditions and Measurement Intervals
    1. Ambient Room Temperature
    2. Test Air Temperature
    3. Ambient Relative Humidity
    4. Maximum Air Draft
    5. Measurement Intervals
    C. Test Set-Up for Storage and Storage-Type Instantaneous Water 
Heaters
    D. Test Method for Unfired Hot Water Storage Tanks
    E. Setting the Tank Thermostat for Storage and Storage-Type 
Instantaneous Water Heaters
    1. Gas-fired and Oil-Fired Storage Water Heaters
    2. Electric Storage Water Heaters
    F. Steady-State Requirements and Soak-In Period
    1. Steady-State Verification
    2. Clarifying Statements
    3. Soak-In Period
    G. Definitions for Certain Consumer Water Heaters and Commercial 
Water Heating Equipment
    1. Consumer Water Heaters
    2. Commercial Water Heating Equipment
    3. Residential-Duty Commercial Water Heaters
    4. Storage-Type Instantaneous Water Heaters
    H. Standby Loss Test for Instantaneous Water Heaters and Hot 
Water Supply Boilers
    1. Definition of Flow-Activated Instantaneous Water Heater
    2. Storage Volume Determination for Instantaneous Water Heaters 
and Hot Water Supply Boilers (Excluding Storage-Type Instantaneous 
Water Heaters)
    3. Standby Loss Test Procedures for Instantaneous Water Heaters 
and Hot Water Supply Boilers (Other Than Storage-Type Instantaneous 
Water Heaters)
    I. Test Set-Up for Commercial Instantaneous Water Heaters and 
Hot Water Supply Boilers
    1. Location of Outlet Water Temperature Measurement
    2. Multiple Outlet Water Connections
    3. Supply and Outlet Water Valves
    4. Additional Comments
    5. Test Set-Up for Instantaneous Water Heaters and Hot Water 
Supply Boilers
    J. Test Procedure for Rating Commercial Heat Pump Water Heaters
    1. Definitions of CHPWH
    2. Test procedure for CHPWH
    K. Gas Pressure
    L. Fuel Input Rate
    1. Certification Provisions
    2. Enforcement Provisions
    M. Default Values for Certain Test Parameters for Commercial 
Water Heating Equipment
    N. Certification Requirements
    O. Other Issues
    1. Timing of the Test Procedure and Energy Conservation 
Standards Rulemakings
    2. Other Comments
    3. Waiver Requests

[[Page 79263]]

IV. Procedural Issues and Regulatory Review
    A. Review Under Executive Orders 12866
    B. Review Under the Regulatory Flexibility Act
    1. Need for, and Objectives of, the Rule
    2. Significant Issues Raised in Response to the IRFA
    3. Description and Estimate of the Number of Small Entities 
Affected
    4. Description and Estimate of Compliance Requirements
    5. Significant Alternatives to the Rule
    C. Review Under the Paperwork Reduction Act of 1995
    D. Review Under the National Environmental Policy Act of 1969
    E. Review Under Executive Order 13132
    F. Review Under Executive Order 12988
    G. Review Under the Unfunded Mandates Reform Act of 1995
    H. Review Under the Treasury and General Government 
Appropriations Act, 1999
    I. Review Under Executive Order 12630
    J. Review Under the Treasury and General Government 
Appropriations Act, 2001
    K. Review Under Executive Order 13211
    L. Review Under Section 32 of the Federal Energy Administration 
Act of 1974
    M. Congressional Notification
    N. Description of Materials Incorporated by Reference
V. Approval of the Office of the Secretary

I. Authority and Background

    Title III, Part C \1\ of the Energy Policy and Conservation Act of 
1975 (EPCA or the Act), Public Law 94-163 (42 U.S.C. 6311-6317, as 
codified), added by Public Law 95-619, Title IV, section 441(a), sets 
forth a variety of provisions designed to improve energy efficiency.\2\ 
It established the ``Energy Conservation Program for Certain Industrial 
Equipment,'' a program covering certain commercial and industrial 
equipment (hereafter referred to as ``covered equipment''), which 
includes the commercial water heating (CWH) equipment that is the 
subject of this rulemaking. (42 U.S.C. 6311(1)(K)) Title III, Part B 
\3\ of EPCA (42 U.S.C. 6291-6309, as codified) sets forth a variety of 
provisions designed to improve energy efficiency and established the 
Energy Conservation Program for Consumer Products Other Than 
Automobiles. This includes consumer water heaters, which are also 
addressed in this rulemaking. (42 U.S.C. 6292(a)(4))
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    \1\ For editorial reasons, Part C was codified as Part A-1 in 
the U.S. Code.
    \2\ All references to EPCA in this document refer to the statute 
as amended through the Energy Efficiency Improvement Act of 2015 
(EEIA 2015), Public Law 114-11 (April 30, 2015).
    \3\ For editorial reasons, upon codification in the U.S. Code, 
Part B was redesignated as Part A.
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    Under EPCA, the energy conservation programs for consumer products 
and industrial equipment generally consist of four parts: (1) Testing; 
(2) labeling; (3) establishing Federal energy conservation standards; 
and (4) certification and enforcement procedures. The testing 
requirements consist of test procedures that manufacturers of covered 
products and equipment must use as both the basis for certifying to DOE 
that their products and equipment comply with the applicable energy 
conservation standards adopted pursuant to EPCA, and for making 
representations about the efficiency of that equipment. (42 U.S.C. 
6293(c); 42 U.S.C. 6295(s); 42 U.S.C. 6314; 42 U.S.C. 6316)
    The initial test procedures for CWH equipment were added to EPCA by 
the Energy Policy Act of 1992 (EPACT 1992), Public Law 102-486, and 
correspond to those referenced in ASHRAE and Illuminating Engineering 
Society of North America (IESNA) Standard 90.1-1989 (i.e., ASHRAE 
Standard 90.1-1989) which went into effect on October 24, 1992. (42 
U.S.C. 6314(a)(4)(A)) EPCA requires that if an industry test procedure 
that is referenced in ASHRAE Standard 90.1 is amended, DOE must amend 
its test procedure to be consistent with the amended industry test 
procedure, unless DOE determines that the amended test procedure is not 
reasonably designed to produce test results that reflect the energy 
efficiency, energy use, or estimated operating costs of the equipment 
during a representative average use cycle. In addition, DOE must 
determine that the amended test procedure is not unduly burdensome to 
conduct. (42 U.S.C. 6314(a)(2), (3) and (4)(B))
    If DOE determines that a test procedure amendment is warranted, it 
must publish a proposed test procedure in the Federal Register and 
offer the public an opportunity to present oral and written comments. 
(42 U.S.C. 6314(b)(1)-(2)) When amending a test procedure, DOE must 
determine to what extent, if any, the proposed test procedure would 
alter the equipment's energy efficiency as determined under the 
existing test procedure. (42 U.S.C. 6293(e); 42 U.S.C. 6314(a)(4)(C))
    The Energy Independence and Security Act of 2007 (EISA 2007), 
Public Law 110-140, amended EPCA to require that at least once every 7 
years, DOE must review test procedures for each type of covered 
equipment, including CWH equipment, and either: (1) Amend the test 
procedures if the Secretary of Energy (Secretary) determines that the 
amended test procedures would more accurately or fully comply with the 
requirements of 42 U.S.C. 6314(a)(2)-(3),\4\ or (2) publish a notice of 
determination not to amend a test procedure. (42 U.S.C. 6314(a)(1)(A)) 
Under this requirement, DOE must review the test procedures for CWH 
equipment no later than May 16, 2019, which is 7 years after the most 
recent final rule amending the Federal test method for CWH 
equipment.\5\ This final rule satisfies the requirement to review the 
test procedure for CWH equipment within 7 years, as well as the 
aforementioned requirement that DOE amend its test procedure if an 
industry test procedure is updated.
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    \4\ 42 U.S.C. 6314(a)(2) requires that test procedures be 
reasonably designed to produce test results which reflect energy 
efficiency, energy use, and estimated operating costs of a type of 
industrial equipment (or class thereof) during a representative 
average use cycle (as determined by the Secretary), and not be 
unduly burdensome to conduct.
     42 U.S.C. 6314(a)(3) requires that if the test procedure is a 
procedure for determining estimated annual operating costs, such 
procedure must provide that such costs are calculated from 
measurements of energy use in a representative average-use cycle (as 
determined by the Secretary), and from representative average unit 
costs of the energy needed to operate such equipment during such 
cycle. The Secretary must provide information to manufacturers of 
covered equipment regarding representative average unit costs of 
energy.
    \5\ DOE published a final rule in the Federal Register on May 
16, 2012, that, in relevant part, amended its test procedure for 
commercial water heating equipment. 77 FR 28928.
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    DOE's test procedure for CWH equipment is found at 10 CFR 431.106, 
Uniform test method for the measurement of energy efficiency of 
commercial water heaters and hot water supply boilers (other than 
commercial heat pump water heaters).\6\ DOE's test procedure for CWH 
equipment provides a method for determining the thermal efficiency and 
standby loss of CWH equipment. In a direct final rule for test 
procedures for CWH equipment, DOE incorporated by reference certain 
sections of ANSI Standard Z21.10.3-1998 (ANSI Z21.10.3-1998), Gas Water 
Heaters, Volume III, Storage Water Heaters With Input Ratings Above 
75,000 Btu Per Hour, Circulating and Instantaneous. 69 FR 61974, 61983 
(Oct. 21, 2004). On May 16, 2012, DOE published a final rule for 
certain commercial heating, air-conditioning, and water heating 
equipment in the Federal Register that, among other things, updated the 
test procedures for certain CWH equipment by incorporating by reference 
ANSI

[[Page 79264]]

Z21.10.3-2011. 77 FR 28928, 28996. These updates did not materially 
alter DOE's test procedure for CWH equipment.
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    \6\ DOE has reserved a place in its regulations for a test 
procedure for commercial heat pump water heaters at 10 CFR 431.107, 
Uniform test method for the measurement of energy efficiency for 
commercial heat pump water heaters. However, in this final rule, DOE 
is removing 431.107 and addressing the test method for commercial 
heat pump water heaters in Appendix E to Subpart G of 10 CFR 431.
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    The American Energy Manufacturing Technical Corrections Act 
(AEMTCA), Public Law 112-210, was signed into law on December 18, 2012, 
and amended EPCA to require that DOE publish a final rule establishing 
a uniform efficiency descriptor and accompanying test methods for 
consumer water heaters and certain CWH equipment. (42 U.S.C. 
6295(e)(5)) AEMTCA required DOE to replace the current efficiency 
metric for consumer water heaters (energy factor) and the current 
efficiency metrics for commercial water heaters (thermal efficiency and 
standby loss) with a uniform efficiency descriptor. (42 U.S.C. 
6295(e)(5)(C)) Further, AEMTCA required that the uniform efficiency 
descriptor and accompanying test method apply, to the maximum extent 
possible, to all water heating technologies currently in use and to 
future water heating technologies. (42 U.S.C. 6295(e)(5)(H)) However, 
AEMTCA allowed DOE to exclude from the uniform efficiency descriptor 
specific categories of covered water heaters that do not have 
residential uses, that can be clearly described, and that are 
effectively rated using the current thermal efficiency and standby loss 
descriptors. (42 U.S.C. 6295(e)(5)(F))
    DOE published a final rule for test procedures for certain CWH 
equipment on July 11, 2014 (``July 2014 final rule''). 79 FR 40542. The 
July 2014 final rule modified the current consumer water heater metric 
(energy factor) to create uniform energy factor (UEF), the descriptor 
to be used as the uniform efficiency descriptor for all consumer water 
heaters and CWH equipment that have residential uses. Id. at 40544. The 
July 2014 final rule excluded CWH equipment from the uniform descriptor 
equipment that has no residential use, that can be clearly identified 
and described, and that is effectively rated using the current thermal 
efficiency and standby loss efficiency descriptors. In the July 2014 
final rule, DOE defined and adopted a new test method for 
``residential-duty commercial water heaters,'' which are commercial 
water heaters that have residential uses. Id.
    For this final rule for CWH equipment test procedures, DOE is only 
amending test procedures for the CWH equipment classes that are not 
``residential-duty commercial water heaters'' as adopted in the July 
2014 final rule.\7\ On February 27, 2014, DOE published in the Federal 
Register a request for information (February 2014 RFI) to seek public 
comments on several issues associated with the current test procedure 
for CWH equipment. 79 FR 10999. On May 9, 2016, DOE published a NOPR 
proposing amendments to its procedures for certain CWH equipment (May 
2016 NOPR). 81 FR 28588. The May 2016 NOPR considered and responded to 
comments received in response to the February 2014 RFI.
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    \7\ Although DOE did not consider amended test procedures for 
residential-duty commercial water heaters, DOE is amending the 
definition for ``residential-duty commercial water heater,'' as 
discussed in section III.G.3.
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    In this final rule, DOE responds to all comments received from 
interested parties in response to the proposals presented in the May 
2016 NOPR, either during the May 2016 NOPR public meeting or in 
subsequent written comments.

II. Synopsis of the Final Rule

    As explained in detail in section III, in this final rule, DOE 
amends subpart G of 10 CFR part 431 to:
     Incorporate by reference certain provisions of the most 
current version of the following industry standards, older versions of 
which are currently incorporated into DOE's regulations: (1) ANSI 
Z21.10.3-2015/CSA 4.3-2015, Gas-fired Water Heaters, Volume III, 
Storage Water Heaters with Input Ratings Above 75,000 Btu Per Hour, 
Circulating and Instantaneous; (2) ASTM Standard Test Method D2156-09, 
Standard Test Method for Smoke Density in Flue Gases from Burning 
Distillate Fuels; (3) ASTM Standard Test Method C177-13, Standard Test 
Method for Steady-State Heat Flux Measurements and Thermal Transmission 
Properties by Means of the Guarded-Hot-Plate Apparatus; and (4) ASTM 
Test Standard Method C518-15, Standard Test Method for Steady-State 
Thermal Transmission Properties by Means of the Heat Flow Meter 
Apparatus;
     Update the requirements for ambient condition 
requirements, measurement locations, and measurement intervals for the 
thermal efficiency and standby loss test procedures;
     Amend the test set-up requirements for storage water 
heaters, storage-type instantaneous water heaters, instantaneous water 
heaters, and hot water supply boilers;
     Update provisions for setting the tank thermostat for 
storage and storage-type instantaneous water heaters prior to the 
thermal efficiency and standby loss tests;
     Update requirements for establishing steady-state 
operation for CWH equipment;
     Update existing and adopt new definitions for certain 
consumer water heaters, certain CWH equipment, residential-duty 
commercial water heater and storage-type instantaneous water heaters;
     Update the test set-up for instantaneous water heaters and 
hot water supply boilers that are tested using a recirculating loop;
     Adopt a new standby loss test procedure for flow-activated 
and externally-activated instantaneous water heaters;
     Modify the standby loss test procedure for internally 
thermostatically-activated instantaneous water heaters;
     Update the test procedure for determination of storage 
volume for instantaneous water heaters and hot water supply boilers 
(other than storage-type instantaneous water heaters);
     Adopt requirements for gas supply pressure and gas outlet 
pressure of gas-fired CWH equipment;
     Adopt a new test procedure for rating commercial heat pump 
water heaters (CHPWHs) based on certain sections incorporated by 
reference from ANSI/ASHRAE Standard 118.1-2012, Method of Testing for 
Rating Commercial Gas, Electric, and Oil Service Water-Heating 
Equipment;
     Adopt provisions for measurement and enforcement of fuel 
input rate; and
     Specify default values for certain parameters for testing 
oil-fired CWH equipment.
    The final rule also amends 10 CFR part 429 to clarify certification 
requirements and enforcement procedures for certain CWH equipment, and 
amends certain definitions in 10 CFR part 430. Specifically, in 10 CFR 
part 430, this final rule removes the definitions of ``Electric heat 
pump water heater'' and ``Gas-fired heat pump water heater,'' and 
revises the definitions of ``Electric instantaneous water heater,'' 
``Electric storage water heater,'' ``Gas-fired instantaneous water 
heater,'' ``Gas-fired storage water heater,'' ``Oil-fired instantaneous 
water heater,'' and ``Oil-fired storage water heater.''

III. Discussion

    Table III-1 presents the list of interested parties that submitted 
written comments in response to the May 2016 NOPR.

[[Page 79265]]



Table III-1--Interested Parties Providing Comment in Response to the May
                                2016 NOPR
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                                                            Commenter
               Name                    Abbreviation          type\*\
------------------------------------------------------------------------
A.O. Smith Corporation and         A.O. Smith..........               M
 Lochinvar, LLC.
Air-Conditioning, Heating, and     AHRI................              IR
 Refrigeration Institute.
American Gas Association and       Gas Associations....              IR
 American Public Gas Association.
Appliance Standards Awareness      Joint Advocates                   EA
 Project and American Council for   (ASAP and ACEEE).
 an Energy-Efficient Economy.
Bock Water Heaters, Inc..........  Bock................               M
Bradford White Corporation.......  Bradford White......               M
Bradley Corporation..............  Bradley.............               M
California Investor Owned          CA IOUs.............              IR
 Utilities.
Earthlinked Technologies Inc.....  Earthlinked.........               M
Edison Electric Institute........  EEI.................              IR
GE Appliances....................  GE..................               M
HTP, Inc.........................  HTP.................               M
Lochinvar, LLC...................  Lochinvar...........               M
Northwest Energy Efficiency        NEEA................              EA
 Alliance.
Raypak, Inc......................  Raypak..............               M
Rheem Corporation................  Rheem...............               M
Rinnai America Corporation.......  Rinnai..............               M
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* ``IR'': Industry Representative; ``M'': Manufacturer; ``EA'':
  Efficiency/Environmental Advocate.

    These interested parties commented on a range of issues, including 
those identified by DOE in the May 2016 NOPR, as well as other issues 
related to the proposed test procedure. The issues, the comments 
received, DOE's responses to those comments, and the resulting changes 
to the NOPR test procedure proposals for CWH equipment adopted in this 
final rule are discussed in the following subsections.

A. Updated Industry Test Methods

    DOE's test procedure for measuring the energy efficiency for CWH 
equipment currently incorporates by reference the industry standard 
ANSI Z21.10.3-2011 at 10 CFR 431.105. Additionally, DOE lists ASTM 
Standard Test Methods D2156-80, C177-97, and C518-91 as sources of 
information and guidance in 10 CFR 431.104. DOE defines ``ASTM Standard 
Test Method D2156-80'' at 10 CFR 431.102, and points to this source in 
DOE's current test procedure at 10 CFR 431.106. DOE points to ASTM 
C177-97 and ASTM C518-91 in its definition of ``R-value'' at 10 CFR 
431.102. In the May 2016 NOPR, DOE proposed to update the references to 
industry test methods to incorporate the most recent version available 
of each of these standards.
    As described in section I, with respect to CWH equipment, EPCA 
initially directs DOE to use industry test methods as referenced in 
ASHRAE/IES Standard 90.1, ``Energy Standard for Buildings Except Low-
Rise Residential Buildings.'' (42 U.S.C. 6314(a)(4)(A)) If and when 
such an industry test method is amended, EPCA requires that DOE amend 
its test procedure as necessary to be consistent with the amended 
industry test method unless it determines, by rule published in the 
Federal Register and supported by clear and convincing evidence, that 
the amended test procedure would be unduly burdensome to conduct or 
would not produce test results that reflect the energy efficiency, 
energy use, and estimated operating costs of that equipment during a 
representative average use cycle. (42 U.S.C. 6314(a)(2), (3) and 
(4)(B))
    AHRI and Rheem stated that DOE is obligated to adopt generally 
accepted industry testing procedures and may only adopt an alternate 
procedure upon proving by clear and convincing evidence that the 
industry test standard is not designed to reflect the energy efficiency 
of the equipment being tested or is unduly burdensome to conduct. 
(AHRI, No. 26 at pp. 3-4, Rheem No. 34 at p. 2) AHRI argued that the 
May 2016 NOPR does not address this statutory requirement and instead 
shifts the burden of data production to the regulated industry, and 
further argued that DOE must quantify the benefits of the proposed test 
procedure over the industry test standards. (AHRI, No. 26 at pp. 3-4) 
Rheem asserted that the appropriate reason to amend the current Federal 
test procedure is the statutory requirement to amend the Federal test 
procedure whenever the industry-accepted test standard for commercial 
water heating equipment is amended, and recommended that DOE adopt the 
industry-accepted test procedure rather than amendments to it. Rheem 
added that, in its view, the proposed test procedures lack 
justification, are burdensome, and are contradictory to the 
requirements of Executive Order 12988, ``Civil Justice Reform.'' 
(Rheem, No. 34 at pp. 1-4) A. O. Smith stated that the proposed test 
procedure is not justified by empirical and qualitative data. (A. O. 
Smith, No. 27 at p. 1)
    DOE does not agree with commenters' interpretations of the relevant 
statutory provisions at issue here. Under 42 U.S.C. 6314(a)(4)(B), when 
DOE is triggered by the amendment of an industry test method applicable 
to ASHRAE equipment, the Secretary is directed to undertake an 
assessment of that industry test method to determine whether amendments 
to the Federal test procedure are ``necessary'' to be ``consistent'' 
with the amended industry test method. (There may be cases where the 
industry standard-setting organization reviews its method and puts out 
a new version with minimal or no changes, in which case it may not be 
necessary for DOE to amend its own test procedure.) The term 
``consistent'' does not equate to ``identical,'' so Congress envisioned 
that some differentiation from the industry standard may be necessary. 
However, in the event DOE determines that a more significant deviation 
from the industry test method is needed (i.e., a change that would not 
be ``consistent'' with the industry method), the Secretary must 
determine by rule published in the Federal Register and supported by 
clear and convincing evidence that a Federal test procedure consistent 
with the industry test method would not meet the requirements of 42 
U.S.C. 6314(a)(2) and (3). It is only in the latter case that the clear 
and convincing evidence standard would apply.
    In DOE's experience, industry standard-setting bodies typically

[[Page 79266]]

undertake a thorough and professional approach to their test 
procedures. However, DOE must remain cognizant of its statutory duty to 
ensure that the Federal test method be consistent with the industry 
test method while meeting other statutory requirements at 42 U.S.C. 
6314(a)(2)-(3) (including that the procedure produces test results that 
reflect the energy efficiency, energy use, and estimated operating 
costs of that equipment during a representative average use cycle and 
is not unduly burdensome to conduct). To the extent that DOE identifies 
provisions of the relevant industry test method that would produce 
inaccurate, inconsistent, or unrepeatable results, as demonstrated by 
DOE's testing or analysis, such results would be unlikely to reflect a 
product's representative average energy efficiency or use. Such 
findings would demonstrate that the industry test procedure would not 
meet the statutory requirements of 42 U.S.C. 6314(a)(2)-(3) without 
alteration, thereby justifying DOE's decision to modify the industry 
test procedure (or in certain instances, even to deviate from the 
industry test procedure entirely, in which case the clear and 
convincing evidence standard would apply). That is why DOE usually 
adopts certain sections of industry test methods rather than adopting 
industry methods wholesale and adjusts the industry test methods as 
needed to satisfy the aforementioned statutory requirements. Such is 
the case here, where DOE is adopting amended test procedures that are 
largely consistent with the industry test methods (parts of which are 
incorporated by reference), and any deviations from those industry test 
methods adopted in this final rule are intended to clarify the test 
method to ensure consistent application, improve repeatability, or make 
the test method more representative of the energy efficiency during a 
representative average use cycle, and ensure that the test procedure is 
not unduly burdensome to conduct.
    DOE is tasked with providing clear, repeatable procedures through 
the rulemaking process. The differences between the Federal test 
methods that DOE is adopting in this final rule and the industry test 
methods, and the rationale for these differences, are explained in 
detail in the sections that follow. As one example, a major difference 
between the test method DOE is adopting in this final rule and the 
method contained in ANSI Z21.10.3-2015 is the method for setting the 
thermostat for gas-fired and oil-fired storage water heaters--DOE 
requires the thermostat be set based on the reading from the top-most 
thermostat, while ANSI Z21.10.3-2015 requires the thermostat be set 
based on the mean temperature of the water stored within the tank. As 
discussed in detail in section III.E.1 below, certain CWH designs 
having a large amount of stratification cannot achieve the mean tank 
temperature of 140  5[emsp14][deg]F required by ANSI 
Z21.10.3-2015. Thus, if DOE were to adopt the industry method 
wholesale, there would be certain models that could not be tested in 
accordance with the test procedure. Further, the thermostats of gas-
fired and oil-fired storage water heaters are generally set in the 
field to deliver water at the temperature needed for the application, 
without regard to the mean temperature of the water stored within the 
tank, as it is typically not relevant to the user as long as the water 
at the outlet can meet the temperature requirement for the application. 
Therefore, for this particular example, the DOE test method adopted in 
this final rule differs from the industry standard only to the extent 
that it is appropriate for and can be used for all types of CWH 
equipment. This approach to amending test procedures both maintains 
consistency with the industry test method and ensures that the Federal 
test method meets the statutory requirements set forth above.
    Nonetheless, assuming that DOE requires clear and convincing 
evidence for its amendments to industry standards here, DOE believes 
its findings fully satisfy that threshold. To explain that conclusion, 
DOE articulates how it understands the ``clear and convincing 
evidence'' concept to operate in the context of DOE's establishing of 
test procedures. A rulemaking procedure is unlike the context of 
litigation, where ``clear and convincing'' means that the evidence must 
``place in the ultimate factfinder an abiding conviction that the 
truth'' of its conclusions is ``highly probable.'' \8\ Nonetheless, DOE 
fully recognizes that whenever it must have ``clear and convincing 
evidence'' pursuant to 42 U.S.C. 6314(a), it needs a higher degree of 
confidence in its conclusions than would be required under the 
``preponderance'' standard that ordinarily applies in agency 
rulemaking. In such matters, the administrative record, taken as a 
whole, must justify DOE in a strong conviction that its conclusions are 
highly likely to be correct.\9\
---------------------------------------------------------------------------

    \8\ Colorado v. New Mexico, 467 U.S. 310, 316 (1984).
    \9\ Because a test procedure rulemaking is not a litigation, the 
differences warrant some differences in how the ``clear and 
convincing evidence'' threshold operates. DOE both develops the 
record and reviews it to make findings. Also, as an agency tasked 
with setting policy, DOE is ordinarily expected to use its technical 
judgment.
---------------------------------------------------------------------------

    For purposes of establishing test procedures under 42 U.S.C. 
6314(a), ``clear and convincing evidence'' can include the same sorts 
of evidence that DOE would use in any other rulemaking. But DOE will 
conclude it has ``clear and convincing evidence'' only when it is 
strongly convinced that it is highly likely to have reached appropriate 
findings. With respect to the findings discussed in this rulemaking, 
DOE does have that strong conviction.
    In addition, contrary to AHRI's assertion, DOE is under no 
statutory obligation to quantify the benefits of adopting improved test 
procedures other than to find that the test procedures are not unduly 
burdensome to conduct. In response to Rheem's suggestion that DOE 
simply adopt industry test methods without amendment, where the 
industry-based test procedure contains one or more provisions that 
would prevent it from generating results that meet the requirements of 
the statute, EPCA directs DOE to adopt a Federal test procedure that 
resolves the identified problem(s)--not to adopt the industry method 
unquestioned. See 42 U.S.C. 6314(a)(2), (3) and (4). For the example 
given above, the industry test method cannot be used without 
modification for certain CWH equipment, as those equipment are not 
designed to operate in the manner prescribed by the industry test 
method. Therefore, the energy efficiency resulting from the industry 
test method (if possible to test) would not reflect the energy 
efficiency of that equipment during a representative average use cycle, 
and in such instances EPCA requires DOE to modify the test procedure.
    Consistent with this authority, DOE is adopting a test procedure 
that is generally consistent with the industry-based test procedure. 
The justification and evidence supporting each provision adopted is 
described in the sections that follow, including DOE's compliance with 
Executive Order 12988, which is addressed in section IV.F of this final 
rule.
    The following subsections discuss revisions to DOE's test procedure 
for CWH equipment vis-[agrave]-vis these industry standards.
1. ANSI Z21.10.3 Testing Standard
    As previously noted, DOE's test procedure for measuring the energy 
efficiency for CWH equipment currently incorporates by reference the 
industry

[[Page 79267]]

standard ANSI Z21.10.3-2011 at 10 CFR 431.105. Specifically, the DOE 
test procedures at 10 CFR 431.106 directs one to follow Exhibits G.1 
and G.2 of ANSI Z21.10.3-2011 for measuring thermal efficiency and 
standby loss, respectively. An updated edition of the industry test 
method, ANSI Z21.10.3-2015/CSA 4.3-2015, Gas-fired Water Heaters, 
Volume III, Storage Water Heaters with Input Ratings Above 75,000 Btu 
Per Hour, Circulating and Instantaneous (hereinafter referred to as 
``ANSI Z21.10.3-2015''), was approved on October 5, 2015, and released 
in November 2015.
    In the May 2016 NOPR, DOE proposed to incorporate by reference 
certain sections of ANSI Z21.10.3-2015 in its test procedures for CWH 
equipment. 81 FR 28588, 28595 (May 9, 2016). Specifically, DOE proposed 
to incorporate by reference only Annex E.1 of ANSI Z21.10.3-2015 (which 
corresponds to Exhibit G.1 of ANSI Z21.10.3-2011). As discussed in the 
May 2016 NOPR, DOE did not propose to incorporate by reference Annex 
E.2 of ANSI Z21.10.3-2015 (which corresponds to Exhibit G.2 of ANSI 
Z21.10.3-2011) because of an error in a standby loss equation; however, 
DOE included certain language from Annex E.2 in its standby loss test 
procedures proposed in the May 2016 NOPR. Id. DOE has concluded that 
the standby loss test procedure for storage-type CWH equipment adopted 
in this final rule is consistent with the approach taken by Annex E.2 
of ANSI Z21.10.3-2015; nonetheless, any differences in the DOE test 
method (as discussed in the applicable subsections within section III 
of this notice) are also supported by clear and convincing evidence. CA 
IOUs responded to the May 2016 NOPR by expressing support for updating 
the reference to ANSI Z21.10.3-2015 with as-needed modifications. (CA 
IOUs, No. 23 at p. 1) In the May 2016 NOPR, DOE's proposed test 
procedures included specific references to sections c, f, and j of 
Annex E.1 of ANSI Z21.10.3-2015. 81 FR 28588, 28595 (May 9, 2016) 
However, as discussed in section III.F.1 of this final rule, DOE is 
adopting new requirements for establishing steady-state operation prior 
to the thermal efficiency test, as recommended by several stakeholders. 
Therefore, in this final rule, DOE is not referencing section j of 
Annex E.1 of ANSI Z21.10.3-2015, which includes conduct of the thermal 
efficiency test and establishment of steady-state operation. However, 
DOE is adopting language and equations for determination of thermal 
efficiency that are similar to those included in section j of Annex E.1 
of ANSI Z21.10.3-2015. Consequently, in this final rule DOE is amending 
its test procedures for CWH equipment by incorporating by reference 
sections c and f (``Vent requirements'' and ``Installation of 
temperature-sensing means,'' respectively) of Annex E.1 of ANSI 
Z21.10.3-2015.
    ANSI Z21.10.3-2015 also includes a new standby loss test 
procedure--Annex E.3, Method of test for measuring standby loss for 
tube type instantaneous water heaters with 10 or greater gallons of 
storage. This procedure provides a method to test standby loss of 
instantaneous water heaters and hot water supply boilers, including 
those that require continuous flow of water to activate the burner or 
heating element (i.e., ``flow-activated instantaneous water heaters''). 
DOE reviewed this test procedure for the May 2016 NOPR and discussed 
the issues with incorporating Annex E.3 of ANSI Z21.10.3-2015 as a test 
procedure for conducting the standby loss test for flow-activated 
instantaneous water heaters. Specifically, DOE noted that Annex E.3 of 
ANSI Z21.10.3-2015 contained several apparent errors, such as equations 
that appeared to have typos and variables that were incorrectly 
defined. Further, the test method in Annex E.3 would have ended the 
test after 1 hour, and assumed that the entire amount of thermal energy 
contained in the stored water above room temperature is lost in exactly 
1 hour, regardless of the rate at which the equipment actually loses 
heat. DOE tentatively concluded that such a procedure would unfairly 
assume the same rate of standby losses for models that may lose heat at 
different rates, and would not be representative of the energy 
efficiency of this equipment. DOE discussed these issues in detail in 
section III.G of the May 2016 NOPR. Ultimately, in the May 2016 NOPR, 
DOE proposed a test procedure similar to Annex E.3 of ANSI Z21.10.3-
2015 with modifications to: (1) The equation to calculate the standby 
loss; (2) the conduct of the test; (3) the parameters that need to be 
measured; and (4) the stopping criteria for the test. 81 FR 28588, 
28607-28613 (May 9, 2016). In the May 2016 NOPR, DOE also proposed to 
adopt a different method for determining the storage volume for use in 
the standby loss calculation for flow-activated instantaneous water 
heaters than that specified by Annex E.3 of ANSI Z21.10.3-2015. 
Specifically, DOE proposed to use a weight-based method similar to the 
method specified in section 5.27 of ANSI Z21.10.3-2015, rather than the 
method included in section 5.28 of ANSI Z21.10.3-2015, which leaves the 
actual method for determining storage volume to the discretion of the 
test entity.
    In section III.H of this final rule, DOE discusses the comments 
received from interested parties on the proposed test procedure for 
flow-activated instantaneous water heaters, including comments on the 
methodology used to determine the storage volume. In addition, based on 
the comments received, DOE has expanded the applicability of the 
adopted test procedure to externally thermostatically-activated 
instantaneous water heaters and modified the methodology to determine 
the storage volume to allow the measurement using calculations of 
physical (or design drawing) based dimensions. For additional details, 
see section III.H of this final rule.
2. ASTM Standard Test Method D2156 and Smoke Spot Test
    DOE's current test procedure for oil-fired CWH equipment at 10 CFR 
431.106 points to ASTM Standard Test Method D2156-80. Specifically, DOE 
requires that smoke in the flue does not exceed No. 1 smoke \10\ as 
measured by the procedure in ASTM D2156-80. A more recent version of 
ASTM D2156 was approved on December 1, 2009, and reapproved on October 
1, 2013. After reviewing D2156-80 and D2156-09 for the May 2016 NOPR, 
DOE tentatively concluded that no substantive changes were made between 
these versions in the test method for determining the smoke spot 
number, and therefore DOE proposed to incorporate by reference ASTM 
D2156-09 in its test procedures for oil-fired CWH equipment. 81 FR 
28588, 28595 (May 9, 2016). In response to the May 2016 NOPR, several 
parties expressed support in updating references to ASTM D1246-09. 
(Bock, No. 19 at p. 1; AHRI, No. 26 at p. 13; A.O. Smith, No. 27 at p. 
2) DOE did not receive any other comments on this proposal, and, 
therefore, DOE is incorporating by reference ASTM D2156-09 in its test 
procedures for oil-fired CWH equipment in appendices A, C, and E to 
subpart G of 10 CFR part 431.
---------------------------------------------------------------------------

    \10\ The smoke scale, as described in ASTM D156, consists of ten 
spots numbered consecutively from 0 to 9, ranging in equal 
photometric steps from white through neutral shades of gray to 
black.
---------------------------------------------------------------------------

    DOE's current requirement for the flue gas smoke spot number for 
oil-fired CWH equipment requires that the smoke in the flue does not 
exceed No. 1 smoke;

[[Page 79268]]

however, the regulations do not specify when during the test to 
determine the smoke spot number. To improve consistency and 
repeatability of testing CWH equipment, in the May 2016 NOPR, DOE 
proposed to specify when to conduct the smoke spot test. 81 FR 28588, 
28596 (May 9, 2016). Specifically, DOE proposed to require 
determination of the smoke spot number after steady-state operation has 
been achieved, but prior to beginning measurement for the thermal 
efficiency test. For the thermal efficiency test, DOE proposed to 
require that the smoke spot number be determined after steady-state 
condition has been reached (with steady-state defined as being achieved 
when there is no variation of the outlet water temperature in excess of 
2 [deg]F over a 3-minute period). For the standby loss test, DOE 
proposed to require determination of the smoke spot number after the 
first cut-out \11\ before beginning measurements for the standby loss 
test. DOE also proposed to require that the CO[deg]reading, which is 
required to be measured when testing oil-fired CWH equipment under 
DOE's current test procedures specified at 10 CFR 431.106, also be 
measured at the time required for determination of the smoke spot 
number.
---------------------------------------------------------------------------

    \11\ Cut-out refers to the de-activation of the burner or 
heating element following a control signal that the stored water is 
heated to the thermostat set-point temperature or the call for hot 
water has ended. The thermostat that signals the burner to activate 
or de-activate may be located inside the unit or outside the unit at 
a remote location (e.g., in an external hot water storage tank).
---------------------------------------------------------------------------

    DOE also proposed to clarify that the smoke spot test and 
measurement of CO2 reading are required before each thermal 
efficiency test or standby loss test (as applicable) of oil-fired CWH 
equipment unless no settings on the water heater have been changed and 
the water heater has not been turned off since the end of a previously 
run efficiency test, in which case a second smoke spot test or 
CO2 reading is not required prior to beginning another 
efficiency test (i.e., thermal efficiency or standby loss). Id.
    In response to the May 2016 NOPR, AHRI commented that the 
CO2 reading and smoke spot number should only be measured 
once when input rate of the burner is being set, not before both the 
thermal efficiency and standby loss tests. (AHRI, No. 26 at pp. 8-9) 
A.O. Smith agreed with DOE's proposal regarding when the smoke spot 
test and measurement of CO2 reading are not required, and 
agreed with DOE's proposal that the same requirement for when to 
measure apply to both CO2 reading and the smoke spot test. 
(A.O. Smith, No. 27 at p. 2) Bock agreed with the proposal regarding 
when to conduct the smoke spot measurement before the thermal 
efficiency test, but disagreed with the proposal regarding when to 
conduct the measurement prior to the standby loss test. Specifically, 
Bock stated that confining the smoke spot measurement to the short time 
period between the second cut-in \12\ and second cut-out would add 
unnecessary complexity to the procedure, and that the timing of the 
second cut-in varies. Bock suggested measurement of the smoke spot 
number 15 minutes into initial warm-up, before the first cut-out. 
(Bock, No. 19 at p. 1)
---------------------------------------------------------------------------

    \12\ Cut-in refers to the initiation of the burner or heating 
element operation based on a control signal to raise the temperature 
of stored hot water that has fallen below the required thermostat 
set-point temperature, or to meet an external demand for hot water.
---------------------------------------------------------------------------

    In this final rule, DOE is adopting a requirement similar to its 
proposal that the smoke spot test and CO2 reading 
measurement be conducted before beginning the thermal efficiency test. 
However, given DOE's updated requirements that establish a steady-state 
verification period immediately preceding the thermal efficiency test 
(discussed in section III.F.1 of this final rule), the testing body may 
not know when the steady-state verification period ends and the thermal 
efficiency test begins until after testing is complete. Therefore, DOE 
is requiring that the smoke spot test and CO2 reading 
measurement must be conducted with the burner firing prior to beginning 
measurements for the steady-state verification period.
    In response to AHRI, DOE notes that the determination of the smoke 
spot number and measurement of the CO2 reading is only 
required before the standby loss test if a thermal efficiency test or 
standby loss test was not previously conducted, or if the settings have 
been changed or the water heater turned off after a previously 
conducted test. Therefore, if efficiency tests are conducted 
consecutively, and the water heater settings are not changed or the 
water heater turned off between tests, the method adopted in this final 
rule is in line with AHRI's suggestion that the smoke spot test only be 
required once.
    DOE also recognizes that there may be a short time period between 
the second cut-in and second cut-out for determining the smoke spot 
number, and that the timing of the second cut-in may not be easily 
predictable. Therefore, DOE agrees with Bock that measurement of the 
smoke spot number prior to the first cut-out would be less burdensome. 
When conducting the standby loss test when a thermal efficiency test 
was not conducted immediately prior, the thermostat must be set for the 
standby loss test prior to the first cut-out, but there is no specified 
duration for warm-up. For oil-fired CWH equipment for which a test was 
not previously conducted (or for which settings on the water heater 
have changed since the previous test), DOE is therefore specifying that 
the smoke spot number be determined with the burner firing prior to 
beginning the standby loss test. DOE is not adopting a requirement that 
the smoke spot test number be determined after any specific time before 
beginning the standby loss test, because DOE recognizes that different 
models will take different amounts of time to warm up.
    Additionally, DOE is adopting specifications for the test procedure 
for the set-up for measuring the smoke density for oil-fired CWH 
equipment, as proposed in the May 2016 NOPR. 81 FR 28588, 28641 (May 9, 
2016). Specifically, DOE is establishing a requirement that the smoke-
measuring device be connected to an open-ended tube, and that this tube 
must project into the flue by \1/4\ to \1/2\ of the pipe diameter. 
These requirements are the same as those specified for commercial 
space-heating boilers in AHRI 1500-2015, and DOE did not receive any 
comments related to this proposal.
3. ASTM Test Standards C177 and C518
    DOE's current definition for ``R-value'' at 10 CFR 431.102 
references two industry test methods: ASTM Standard Test Method C177-97 
and ASTM Test Standard Method C518-91.
    A more recent version of ASTM C177 was approved in September 2013 
and published in October 2013 (ASTM C177-13). Additionally, a more 
recent version of ASTM C518 was approved in May 2010 and published in 
June 2010 (ASTM C518-10). After comparing both versions of each 
standard for the May 2016 NOPR, DOE tentatively concluded that, for 
both standards, there are no substantive differences in the procedures 
for measuring R-value between the new and old versions. Therefore, in 
the May 2016 NOPR, DOE proposed to incorporate by reference ASTM 
Standard Test Methods C177-13 and C518-10, and to update its references 
to these versions in the definition for ``R-value'' at 10 CFR 431.102. 
81 FR 28588, 28592 (May 9, 2016).
    In response to the May 2016 NOPR, several interested parties 
expressed support for updating references to ASTM C518 and C177. 
(Bradford White, No. 21 at p.1; AHRI, No. 26 at p. 13; A.

[[Page 79269]]

O. Smith, No. 27 at p. 2; Rheem, No. 34 at p. 4) DOE did not receive 
any other comments on this proposal, and, therefore, DOE is 
incorporating by reference ASTM Standard Test Method C177-13. However, 
since publication of the May 2016 NOPR, DOE became aware of a more 
recent version of ASTM C518 that was approved in September 2015 and 
published in December 2015, ASTM C518-15. After careful review, DOE has 
determined that there are no substantive differences between ASTM C518-
10 and ASTM C518-15. DOE received no feedback which disagreed with 
DOE's proposal to update its reference to ASTM C518 to the 2010 
version. Since the 2015 version of ASTM C518 is not substantially 
different than the 2010 version and in order to maintain up-to-date 
references to industry test methods, DOE is incorporating by reference 
the most recent version of the standard, ASTM C518-15.

B. Ambient Test Conditions and Measurement Intervals

    To improve the repeatability of the thermal efficiency and standby 
loss tests in DOE's current test procedures for CWH equipment, DOE 
proposed several changes to its required ambient test conditions. These 
proposals included: (1) Tightening the ambient room temperature 
tolerance from  10.0[emsp14][deg]F to  
5.0[emsp14][deg]F and the allowed variance from mean ambient 
temperature from  7.0[emsp14][deg]F to  
2.0[emsp14][deg]F; (2) requiring measurement of test air temperature--
the temperature of entering combustion air--and requiring that the test 
air temperature not vary by more than  5[emsp14][deg]F from 
the ambient room temperature at any measurement interval during the 
thermal efficiency and standby loss tests for gas-fired and oil-fired 
CWH equipment; (3) establishing a requirement for ambient relative 
humidity of 60 percent  5 percent during the thermal 
efficiency and standby loss tests for gas-fired and oil-fired CWH 
equipment; (4) setting a maximum air draft requirement of 50 ft/min as 
measured prior to beginning the thermal efficiency or standby loss 
tests; and (5) decreasing the time interval for data collection from 
one minute to 30 seconds for the thermal efficiency test and from 15 
minutes to 30 seconds for the standby loss test. 81 FR 28588, 28597 
(May 9, 2016).
    In response to the May 2016 NOPR, several stakeholders disagreed 
with DOE's proposals to tighten requirements on ambient conditions and 
argued that DOE's proposals would be overly burdensome to 
manufacturers. (Bock, No. 19 at p. 1; Bradford White, No. 21 at p. 3; 
CA IOUs, No. 23 at pp. 2-3; HTP, No. 24 at p. 1; AHRI, No. 26 at pp. 6-
8; A.O. Smith, No. 27 at p. 2; Raypak, No. 28 at pp. 5-6; Bradley, NOPR 
Public Meeting Transcript, No. 20 at p. 33; Rheem, No. 34 at pp. 4-6) 
Bock stated that it supports using the procedures in the most updated 
versions of ANSI Z21.10.3 and ASHRAE 118.1. (Bock, No. 19 at p. 1) 
Bradford White further argued that the proposed changes are not merited 
because they would not affect efficiency ratings. (Bradford White, No. 
21 at p. 3) CA IOUs stated that the proposed tightening of requirements 
would not provide a significant improvement in accuracy. (CA IOUs, No. 
23 at pp. 2-3)
    A.O. Smith suggested that DOE's proposed modifications to the 
required ambient conditions would be very difficult to meet with large 
equipment with significant makeup air requirements. A.O. Smith also 
pointed out that a model of CWH equipment with a rated input of 2 
million Btu/h would consume fresh air at a rate of 400 cfm, and that 
there are over 30 models of CWH equipment on the market with a rated 
input of 2 million Btu/h or greater. (A.O. Smith, No. 27 at p. 2) AHRI, 
A.O. Smith, and Raypak argued that laboratories in which CWH equipment 
is typically tested have multiple ongoing activities, with doors 
opening and closing, and that conditioning air in such a facility to 
meet DOE's proposed ambient condition requirements would be unduly 
burdensome to manufacturers. (AHRI, No. 26 at p. 7; A.O. Smith, No. 27 
at p. 2; Raypak, No. 28 at p. 6) Bradford White indicated that costs 
per manufacturer to laboratory upgrades required to meet DOE's proposed 
requirements would be hundreds of thousands of dollars or require 
purchase of environmental chambers which cost at least $120,000 each; 
AHRI suggested that the cost of complying with the proposed 
requirements would range from $250,000 to $1 million per manufacturer; 
Raypak suggested the cost to upgrade its facility would be $500,000 to 
$1.5 million; Rinnai suggested that meeting DOE's proposed requirements 
would require environmental chambers which cost more than $250,000 
each; and Rheem suggested that the cost for laboratory upgrades would 
be greater than $500,000. (Bradford White, No. 21 at p. 3; AHRI, No. 26 
at p. 7; Raypak, No. 28 at p. 6; Rinnai, No. 34 at p. 1; Rheem, No. 34 
at p. 5) NEEA agreed with DOE's proposed ambient condition requirements 
and suggested that the requirements would improve the consistency of 
DOE's test procedures with little or no additional test burden. (NEEA, 
No. 30 at p. 2)
    In light of comments received, DOE is not adopting the more 
stringent ambient conditions (i.e., tighter tolerance on ambient room 
temperature, ambient relative humidity requirements) that were proposed 
in the May 2016 NOPR that may have added to test burden for 
manufacturers. Therefore, DOE considers these comments mitigated. 
However, DOE is adopting changes related to its other proposals 
regarding test air temperature, maximum air draft, and data collection 
intervals, and the specific actions that DOE is taking on each of the 
proposed requirements and the potential test burden associated with 
each action are discussed separately in detail in this section.
    Joint Advocates suggested that DOE should require collection and 
reporting of data for relative humidity, air temperature, and 
barometric pressure. (Joint Advocates, No. 32 at p. 2) CA IOUs 
commented that DOE should consider the impact of barometric pressure on 
the results of efficiency testing of CWH equipment because it affects 
how much moisture can be held in air. CA IOUs also requested that DOE 
conduct an uncertainty analysis to demonstrate that tighter temperature 
and humidity tolerances are warranted. (CA IOUs, No. 23 at p. 3) DOE is 
not aware of any data demonstrating that barometric pressure 
significantly affects the measured efficiency for CWH equipment, and 
has therefore not found it necessary to regulate the ambient barometric 
pressure of test rooms for any heating products. In response to the May 
2016 NOPR, no commenters provided such data. Therefore, DOE is not 
adopting barometric pressure requirements in this final rule. 
Furthermore, with regard to the Join Advocates suggestion, DOE notes 
that reported values resulting from testing are typically based on test 
results of a sample that contains two or more units, which could have 
slightly different relative humidity and air temperatures during 
testing. Manufacturers then report representative values in accordance 
with the requirements of 10 CFR 429. Because reported values for 
relative humidity and air temperature would be based on multiple unit 
samples and would not correspond to a single efficiency rating 
resulting from a specific set of ambient conditions, this information 
would be of little value to commercial consumers. Therefore, DOE is 
declining to adopt these reporting requirements at this time.
    The following subsections discuss the specific comments on each of 
the proposed changes for the ambient test

[[Page 79270]]

conditions, along with DOE's response and decision.
1. Ambient Room Temperature
    Bradford White, AHRI, and Rheem noted that DOE's proposal to 
tighten the ambient room temperature requirement from 75[emsp14][deg]F 
 10.0[emsp14][deg]F to 75[emsp14][deg]F  
5.0[emsp14][deg]F would preclude the testing of both consumer water 
heaters and commercial water heating equipment in the same test 
laboratory, because DOE's test procedure for consumer water heaters 
requires that the ambient room temperature be maintained between 
65[emsp14][deg]F and 70[emsp14][deg]F. (Bradford White, No. 19 at p. 3; 
AHRI, No. 26 at p. 7; Rheem, No. 34 at p. 5) While Bradford White, 
AHRI, and A.O. Smith argued that DOE's proposal to decrease the 
permitted variance from mean ambient temperature during testing from 
 7.0[emsp14][deg]F to  2.0[emsp14][deg]F would 
require costly upgrades to HVAC systems in testing facilities, they 
supported decreasing the allowed variance from  
7.0[emsp14][deg]F to  5.0[emsp14][deg]F. (Bradford White, 
No. 19 at p. 3; AHRI, No. 26 at p. 7; A.O. Smith, No. 27 at p. 18) 
Bradford White further noted that most manufacturers could accommodate 
a decrease in the allowed variance to  5.0[emsp14][deg]F 
using their existing laboratory HVAC systems. (Bradford White, No. 19 
at p. 3) A.O. Smith further noted that decreasing the allowed variance 
to  5.0[emsp14][deg]F would not be burdensome to 
manufacturers because rapid variations in supply air flow and 
temperature could be avoided. (A.O. Smith, No. 27 at p. 18)
    DOE agrees with commenters that establishing a narrower range for 
ambient room temperature such that consumer water heaters and 
commercial water heating equipment cannot be tested at the same time 
could be overly burdensome to some manufacturers. Therefore, DOE is 
maintaining its current ambient room temperature requirement for 
testing of CWH equipment at 75[emsp14][deg]F  
10.0[emsp14][deg]F. In light of comments from several commenters that a 
decrease in the permitted variance from mean ambient temperature during 
testing from  7.0[emsp14][deg]F to  
5.0[emsp14][deg]F would not be burdensome to manufacturers, DOE is 
adopting a requirement that the ambient temperature must not vary from 
the mean temperature during testing by more than  
5.0[emsp14][deg]F. This requirement is consistent with the requirement 
in ANSI Z21.10.3-2015, but slightly more stringent to improve 
repeatability. Based on the comments received, DOE believes this change 
would not add undue burden and would improve the repeatability of the 
test.
    In the May 2016 NOPR, DOE proposed that the ambient room 
temperature be measured at the same interval during the soak-in period 
as during the thermal efficiency and standby loss tests--30 seconds. 81 
FR 28588, 28641, 289644 (May 9, 2016). However, DOE believes that 
measurement of the ambient room temperature at frequent intervals 
throughout the 12-hour soak-in period is unnecessary. Unlike for an 
efficiency test (i.e., thermal efficiency or standby loss) or the 
steady-state verification period, measurements from the soak-in period 
are not used in calculation of an efficiency metric or in verification 
of steady-state operation. The purpose of the soak-in period is simply 
to allow the tank insulation of storage water heaters and storage-type 
instantaneous water heaters to reach thermal equilibrium between the 
ambient room temperature and the stored water temperature. DOE believes 
that as long as no actions are taken that would change the ambient room 
temperature during the soak-in period, the ambient room temperature 
need only be measured prior to beginning the soak-in period. Therefore, 
DOE is adopting a requirement that the ambient room temperature be 
maintained at 75[emsp14][deg]F  10[emsp14][deg]F during the 
soak-in period as measured prior to beginning the soak-in period, and 
that no actions be taken during the soak-in period that would cause the 
ambient room temperature to deviate from this range.
2. Test Air Temperature
    In the May 2016 NOPR, DOE proposed to require measurement of test 
air temperature--the temperature of entering combustion air--and 
require that the test air temperature not vary by more than  5[emsp14][deg]F from the ambient room temperature at any 
measurement interval during the thermal efficiency and standby loss 
tests for gas-fired and oil-fired CWH equipment. 81 FR 28588, 28597 
(May 9, 2016). Bradford White and Raypak disagreed with DOE's proposed 
requirements for test air temperature. (Bradford White, No. 19 at pp. 
3-4; Raypak, No. 28 at pp. 5-6) Bradford White and AHRI argued that 
measurement of test air temperature at each air inlet would be 
redundant given the required measurement of ambient room temperature, 
because DOE's ambient room temperature requirement would apply to 
entering combustion air. (Bradford White, No. 19 at pp. 3-4; AHRI, No. 
26 at p. 8) Bradford White further argued that DOE's ambient room 
temperature requirement would apply to entering combustion air because 
most models of CWH equipment are tested with minimal vent length, and 
therefore the combustion air inlet would be very close to the water 
heater and location of ambient room temperature measurement. Bradford 
White also asserted that DOE's proposal would present complications for 
water heaters with air inlets on the bottom of the unit and for models 
that draw combustion air from the periphery of the water heater, and 
that at least three thermocouples would likely be needed in these cases 
to measure test air temperature. Braford White also stated that adding 
multiple additional thermocouples to a data acquisition system would be 
more burdensome than suggested by DOE. (Bradford White, No. 19 at pp. 
3-4) AHRI commented that the requirement to measure test air 
temperature within 2 feet of the combustion air inlet would not be 
possible for models with concentric direct venting. AHRI also argued 
that measuring the test air temperature for each air inlet for water 
heaters with multiple air inlets would be an unnecessary burden, and 
that one properly located temperature sensor could adequately monitor 
incoming air temperature for such water heaters. (AHRI, No. 26 at pp. 
7-8) Raypak questioned why DOE proposed to require measurement of test 
air temperature, arguing that it does not affect measured efficiency 
and that DOE has not provided evidence that test air temperature 
affects accuracy or repeatability of test results. (Raypak, No. 28 at 
pp. 5-6)
    DOE believes that the temperature of entering combustion air, or 
test air temperature, can have a significant effect on the measured 
efficiency of a water heater. An increased combustion air temperature 
increases the enthalpy of the entering air to the water heater, and 
this increased combustion air enthalpy provides for additional heating 
of water that is not reflected in the calculation of thermal 
efficiency. While DOE's current test procedure for CWH equipment does 
include a requirement for ambient room temperature, this value is only 
measured at a single location. Therefore, it is possible that the air 
temperatures could differ between the locations of measurement of 
ambient room temperature and test air temperature. As mentioned by 
AHRI, some models of CWH equipment are tested with direct venting 
systems, and DOE notes that the combustion air intake vent for such 
equipment would likely not be located in the immediate vicinity of the 
CWH equipment. Therefore, measurement of ambient room temperature would 
not be representative of the test air temperature for such equipment. 
DOE notes that

[[Page 79271]]

Raypak did not provide a rationale to support its assertion that test 
air temperature does not affect the measured efficiency. DOE also notes 
that AHRI 1500-2015, the industry-consensus test standard for 
commercial packaged boilers, includes similar requirements for 
measurement of both ambient room temperature and test air temperature. 
DOE does not believe that there is a significant difference between 
testing CWH equipment and commercial packaged boilers that would make 
measuring and recording test air temperature overly burdensome for CWH 
equipment. DOE acknowledges that, in certain cases, the air inlet(s) to 
the water heater may be close enough to the required location for 
measurement of ambient room temperature that there may not be a 
significant difference in temperature measured at the two locations. 
However, after consultation with independent testing laboratories, 
requiring additional temperature sensors to a data acquisition system 
to record another air temperature measurement (or multiple 
measurements) for the combustion air does not appear to present a 
significant burden to manufacturers, as it would be a simple, one-time 
task.
    In this final rule, for gas-fired and oil-fired CWH equipment, DOE 
is adopting a requirement that test air temperature be measured within 
2 feet of the air inlet to the water heater. DOE also is adopting a 
requirement that the test air temperature may not vary by more than 
 5[emsp14][deg]F from the ambient room temperature at any 
measurement interval during the thermal efficiency or standby loss 
tests, as applicable. DOE concludes that the additional requirements 
for test air temperature are consistent with the industry standard, 
ANSI Z21.10.3-2015, as these requirements do not change or conflict 
with any requirements in the industry standard. Instead, the 
requirements pertaining to test air temperature provide a more detailed 
approach to maintaining the room temperature and will ensure consistent 
and repeatable temperatures within the test area.
    Regarding AHRI's comments with respect to measuring test air 
temperature for models with direct venting, DOE's intent by the phrase 
``air inlet to the water heater'' in the proposed requirement was to 
refer to the site where combustion air enters either the water heater 
or air intake vent, if applicable. However, DOE acknowledges that more 
specific phrasing is warranted to clarify the measurement location for 
models tested with direct venting. Therefore, DOE is adopting language 
such that the test air temperature must be measured within two feet of 
the air inlet to the water heater or the inlet to the combustion air 
intake vent, as applicable.
    In the May 2016 NOPR, DOE proposed a location for the measurement 
of the test air temperature for units without a dedicated air inlet. 81 
FR 28588, 28597 (May 9, 2016). Specifically, DOE proposed that in this 
case, the test air temperature would be measured within two feet of a 
location on the water heater where combustion air would enter the unit. 
DOE believes that this provision provide adequate instruction as to how 
to test units that draw combustion air from the periphery of the water 
heater, which was raised as a potential issue by Bradford White. 
Therefore, DOE is adopting the language proposed in the May 2016 NOPR 
for how to measure test air temperature for units without a dedicated 
air inlet. For such a unit, the test air temperature must be measured 
within two feet of any location on the water heater where combustion 
air is drawn. Additionally, for such a unit, DOE's adopted requirements 
would only require measurement of test air temperature at one location, 
not three, as asserted by Bradford White. For example, if a unit draws 
combustion air through a gap between the burner tray and the bottom of 
the tank, then the test air temperature must be measured within two 
feet of that gap.
    Regarding Bradford White's comment that test air temperature 
measurement would be complicated for units with an air inlet on the 
bottom of the water heater, DOE believes that its provisions adopted in 
this final rule adequately address this issue. For water heaters that 
draw air from the periphery of the bottom of the water heater, DOE's 
previously discussed provision for how to measure test air temperature 
for units without a dedicated air inlet would apply. DOE is unaware of 
any models of CWH equipment on the market with a dedicated air inlet on 
the bottom of the water heater (i.e., in between the water heater 
bottom and the ground), and suspects that this would be a undesirable 
configuration, as the small clearance between the water heater bottom 
and the ground would likely obstruct adequate flow of entering 
combustion air. However, if such a configuration of CWH equipment 
exists, the test air temperature would be measured at any location 
within two feet of the air inlet on the bottom of the water heater 
under the procedure adopted in this final rule. DOE presumes that any 
clearance between the bottom of the water heater and the ground that is 
sufficiently large for providing adequate air flow would also be 
sufficiently large for installing a temperature sensor(s) for 
measurement of test air temperature.
    DOE disagrees with AHRI that measurement of test air temperature 
should not be required at each air inlet for models of CWH equipment 
with multiple air inlets. For units that have multiple air inlets (such 
as stacked, modular units with multiple air inlets that each correspond 
to a separate burner and heat exchanger), DOE believes that the 
efficiency of the unit would be affected by the entering combustion air 
temperature to all air inlets, and that a requirement to measure test 
air temperature at each air inlet is justified. As previously 
discussed, DOE does not believe that installing multiple temperature 
sensors to measure test air temperature would present a significant 
burden to manufacturers. Therefore, DOE is adopting a requirement that 
test air temperature be measured at each air inlet for units with 
multiple air inlets, and that the specification for no variation of 
more than  5 [deg]F from the ambient room temperature 
applies to the test air temperature measured at each air inlet.
    Given the requirement to measure test air temperature within two 
feet of the air inlet to the water heater, the location of test air 
temperature measurement may be close to the water heater burner. 
Therefore, DOE suspects that the temperature sensor used to measure 
test air temperature might be subject to radiation from the burner. To 
prevent an impact from such radiation on the measurement of test air 
temperature, DOE is adopting a requirement that the temperature sensor 
used to measure test air temperature be shielded from radiation. DOE 
notes that such a requirement for shielding temperature measurement 
from radiation is included in ANSI Z21.10.3-2015 for the temperature 
sensor used to measure ambient room temperature. Additionally, DOE 
understands that shielding temperature measurements from radiation is 
common industry practice and would not present any significant burden 
to manufacturers.
3. Ambient Relative Humidity
    In response to DOE's proposed requirements for ambient relative 
humidity, several commenters argued that relative humidity does not 
have an effect on results of efficiency testing of CWH equipment 
because the tests do not require collection of condensate. (Bradford 
White, No. 19 at p. 2; AHRI, No. 26 at p. 8; A.O. Smith, No. 27 at p. 
2; Raypak, No. 28 at p. 6; Rinnai, No. 31

[[Page 79272]]

at p. 1) CA IOUs commented that the extent to which relative humidity 
affects the measured efficiency of condensing water heaters is unclear. 
(CA IOUs, No. 24 at p. 3) Joint Advocates suggested that relative 
humidity requirements should not apply to non-condensing gas-fired and 
oil-fired CWH equipment. (Joint Advocates, No. 32 at p. 2) Bradford 
White and Rheem commented that it would be difficult to meet DOE's 
proposed relative humidity requirements in all geographic locations at 
all times of the year, as these factors can result in significant 
variation in ambient relative humidity. (Bradford White, No. 21 at pp. 
2-3; Rheem, No. 34 at p. 5) Rheem further argued that meeting DOE's 
proposed relative humidity requirements would likely require that a 
test room be maintained at a positive pressure, and asserted that it 
would be difficult to connect humidistats to a data acquisition system. 
Rheem also stated that a less stringent tolerance is needed for an 
ambient relative humidity requirement, and that more data showing any 
correlation between relative humidity and water heater performance are 
needed before DOE sets a requirement for relative humidity. (Rheem, No. 
34 at p. 5)
    In light of comments received, DOE has concluded that the potential 
burden of controlling ambient humidity is not justified at this time, 
given the amount of make-up air for combustion that would need to be 
conditioned to supply larger CWH equipment during testing. 
Manufacturers asserted that controlling the ambient humidity will not 
have a substantial impact on ratings and should not be held within a 
tolerance. In DOE's view any variation in the resulting energy 
efficiency rating from varying levels of ambient humidity would be 
adequately captured by the existing tolerances for both certification 
and enforcement in DOE's regulations. Therefore, DOE is not adopting a 
requirement that ambient relative humidity be maintained at any 
specific level for CWH equipment other than commercial heat pump water 
heaters. DOE is establishing a wet bulb temperature requirement for 
commercial heat pump water heaters based on relevant industry test 
standards, as discussed in section III.J of this final rule.
4. Maximum Air Draft
    In the May 2016 NOPR, DOE proposed a maximum air draft requirement 
of 50 ft/min as measured prior to beginning the thermal efficiency or 
standby loss tests. 81 FR 28588, 28597 (May 9, 2016). Bradford White 
and A.O. Smith agreed with DOE's proposed maximum air draft 
requirement, but commented that the requirement should not necessitate 
the connection of the draft-measuring device to the data acquisition 
system. (Bradford White, No. 19 at p. 4; A.O. Smith, No. 27 at p. 17) 
A.O. Smith also stated that measurement of air draft may have a large 
uncertainty at 50 ft/min, and recommended that DOE assign a tolerance 
for the measurement of air draft and require the draft-measuring device 
to meet International Organization for Standardization (ISO) 
requirements. (A.O. Smith, No. 27 at p. 17) Raypak disagreed with DOE's 
proposed maximum air draft requirement, and argued that there is no 
evidence that such a requirement would affect results of testing of CWH 
equipment. Additionally, Raypak argued that most CWH manufacturers do 
not manufacture residential water heaters, and that DOE was therefore 
mistaken to presume that many CWH equipment manufacturers would not 
need to purchase devices for measuring air draft as these devices are 
already required for testing residential water heaters. (Raypak, No. 28 
at p. 5) Rheem argued that DOE's proposed maximum air draft requirement 
would be appropriate for the standby loss test, but unnecessary for the 
thermal efficiency test. Rheem also asserted that maintaining a maximum 
air draft less than 50 ft/min would be difficult while also maintaining 
the stricter ambient conditions proposed by DOE in the May 2016 NOPR. 
(Rheem, No. 34 at p. 6)
    In this final rule, DOE is adopting its proposed requirement for a 
maximum air draft of 50 ft/min to clarify the requirement in ANSI 
Z21.10.3-2015 that the test area be ``protected from drafts.'' Because 
ANSI Z21.10.3-2015 already includes a requirement for protecting the 
test area from drafts, DOE concludes that this change provides 
additional detail but is consistent with the industry standard. DOE 
believes that this clarification reduces ambiguity in ANSI Z21.10.3-
2015 to allow for a more repeatable test. This requirement is also 
similar to the requirement that DOE adopted for testing consumer water 
heaters and certain commercial water heaters in the July 2014 final 
rule. 79 FR 40542, 40569 (July 11, 2014). Specifically, DOE is adopting 
a requirement that the air draft be measured prior to beginning the 
thermal efficiency and standby loss tests, within three feet of the 
jacket of the water heater, and that no actions can be taken during the 
conduct of the tests that would increase the air draft near the water 
heater being tested.
    In response to Raypak's comment that there is no evidence that the 
air draft affects the performance of CWH equipment, DOE notes that 
Annex E.1 of ANSI Z21.10.3-2015 already requires that water heater 
placement in the test room shall be protected from drafts. DOE believes 
that if the draft had no impact on the test result, the industry test 
standard, ANSI Z21.10.3-2015, would not require the test to be done in 
an area protected from drafts. Therefore, DOE believes that there is an 
understanding amongst the majority of the industry that air draft from 
sources such as room ventilation registers, windows, or other external 
sources of air movement, during the test can affect the performance of 
CWH equipment. DOE also believes that 50 ft/min is a reasonable maximum 
value, as it is consistent with DOE's requirement for consumer water 
heaters. DOE also notes that many manufacturers of CWH equipment also 
manufacture consumer water heaters and residential-duty commercial 
water heaters. DOE identified at least 17 of 29 CWH equipment 
manufacturers (excluding rebranders) that also manufacture consumer 
water heaters or residential-duty commercial water heaters. For CWH 
equipment manufacturers who do not also manufacture water heaters 
subject to the Part 430, Appendix E test procedure (and therefore may 
not already have draft-measuring devices in their test labs), DOE 
expects the costs and burden associated with purchasing air draft-
measuring devices that do not have the capability of connection to data 
acquisition system to be insignificant. DOE discusses the potential 
costs of these requirements as they pertain to small business 
manufacturers in section 0.
    Regarding digital measurement of air draft, DOE's maximum air draft 
requirement does not require digital measurement. DOE is only adopting 
a requirement to measure the air draft once at the beginning of the 
test, so connection to a data acquisition system would be unnecessary. 
Additionally, DOE is not establishing any requirements on the type or 
accuracy of device used to measure the air draft. DOE notes that it 
currently prescribes a similar maximum air draft requirement for 
consumer and residential-duty commercial water heaters and has no such 
requirements on the draft-measuring device in that test procedure at 
appendix E to subpart B of 10 CFR part 430. DOE believes the test 
entity can determine the appropriate device and accuracy for this 
measurement.

[[Page 79273]]

Additionally, DOE is not establishing a tolerance on its maximum air 
draft requirement. DOE believes that a tolerance is unnecessary on a 
maximum value--the air draft must be no greater than 50 ft/min, but any 
draft below this value meets the requirement.
    DOE acknowledges that the air draft may potentially have a greater 
impact on the results of the standby loss test than on those of the 
thermal efficiency test. However, once again noting the draft 
protection provision in ANSI Z21.10.3-2015, DOE has concluded that 
there may still be an effect on the results of the thermal efficiency 
test, and that the measurement of air draft, just once before the test 
begins, does not present a significant burden to manufacturers. 
Therefore, DOE is adopting the maximum air draft requirement for both 
the thermal efficiency and standby loss tests. DOE notes that it is not 
adopting in this final rule the more stringent ambient condition 
requirements (i.e., narrower tolerance on ambient room temperature, 
requirement to maintain ambient relative humidity within a specified 
range) that Rheem argued would make the proposed maximum air draft 
requirement difficult to meet.
    In the May 2016 NOPR, DOE proposed that the maximum draft 
requirement also apply to the soak-in period. 81 FR 28588, 28597 (May 
9, 2016). However, DOE has determined that this requirement is not 
necessary for the soak-in period. The purpose of the maximum air draft 
requirement is to improve repeatability of the thermal efficiency and 
standby loss tests by preventing large air drafts that might cause 
significantly higher tank heat losses in some tests than in others. DOE 
believes that this concern does not apply to the soak-in period, the 
purpose of which is simply to establish thermal equilibrium in the tank 
insulation, and during which energy consumption is not measured. 
Therefore, DOE is not adopting a maximum air draft requirement for the 
soak-in period.
5. Measurement Intervals
    Bradford White, AHRI, and Raypak opposed DOE's proposal to decrease 
the required data collection interval from 1 minute to 30 seconds for 
the thermal efficiency test and from 15 minutes to 30 seconds for the 
standby loss test. (Bradford White, No. 19 at p. 4; AHRI, No. 26 at pp. 
6-7; Raypak, No. 28 at pp. 6-7) A.O. Smith and Rheem opposed DOE's 
proposal to decrease the time interval to 30 seconds specifically for 
the standby loss test. (A.O. Smith, No. 27 at p. 19; Rheem, No. 34 at 
p. 5)
    AHRI and Raypak stated that DOE did not provide evidence or data to 
suggest that decreasing the time interval would improve accuracy or 
affect efficiency. (AHRI, No. 26 at pp. 6-7; Raypak, No. 28 at pp. 6-7) 
AHRI argued that measurements every 15 minutes during the standby loss 
test are sufficient, and that, if a measurement is within tolerance at 
two consecutive 15-minute readings, then it is reasonable to assume 
that the measurement was maintained within tolerance during the entire 
15-minute period between measurements. (AHRI, NOPR Public Meeting 
Transcript, No. 20 at pp. 32-33)
    Bradford White argued that DOE's proposal would make data files 
large and difficult to analyze. (Bradford White, No. 19 at p. 4) To 
accommodate DOE's proposed time intervals for data collection, AHRI 
commented that some manufacturers might need to upgrade their 
facilities, and Raypak and Rheem argued that small manufacturers might 
need to purchase or upgrade data acquisition systems. (AHRI, No. 26 at 
pp. 6-7; Raypak, No. 28 at pp. 6-7; Rheem, No. 34 at p. 5) A.O. Smith 
argued that no readings other than time and temperature should be 
required at intervals that would necessitate connection to a data 
acquisition system because most other measurement devices used for 
testing CWH equipment are not designed to communicate with a data 
acquisition system. (A.O. Smith, No. 27 at p. 18) Raypak argued that 
the costs for connecting devices to a data acquisition system are 4-5 
times higher than suggested by DOE in the May 2016 NOPR. (Raypak, No. 
28 at pp. 6-7) Rheem further acknowledged that data collection 
intervals can be reduced with current equipment. A.O. Smith and Rheem 
also asserted that DOE's proposed reduced measurement interval would 
lead to an increased likelihood that tests would have to be re-run if 
any parameters were to fall out of the allowable range during the test. 
(A.O. Smith, No. 27 at p. 18; Rheem, No. 34 at p. 5)
    DOE proposed requirements for more frequent data collection to 
improve the resolution of test data, and therefore, to ensure that test 
conditions are adequately met throughout the test. DOE disagrees with 
AHRI that a value can be assumed to be maintained within tolerance in a 
15-minute period between readings when measurements at each 15-minute 
interval are within tolerance, which is further supported by the 
comments of Rheem and A.O. Smith. DOE believes that 15 minutes is a 
sufficiently long time for variation in any one of several parameters 
to potentially have a significant effect on measured standby loss. DOE 
notes that the standby loss test measures a significantly lower energy 
consumption than does the thermal efficiency test, and that the 
measured standby loss is therefore particularly sensitive to 
fluctuations in ambient conditions. Therefore, DOE believes that 
recording measurements every 15 minutes does not provide sufficient 
resolution of test data to ensure that the test results accurately 
capture the variability in the measurement and could lead to inaccurate 
and/or inconsistent results. A requirement for data collection every 
minute ensures that only momentary fluctuations outside of the ambient 
condition tolerances (i.e., those that occur between consecutive 1-
minute readings and are therefore unlikely to have an effect on the 
measured efficiency) are permitted under DOE's test procedure.
    DOE disagrees that its proposed measurement intervals for data 
collection would make data analysis significantly more burdensome. 
Analysis of whether all parameters were maintained within their 
allowable tolerances during testing should be quick and simple in 
spreadsheet software, and the time required for such analysis should 
not depend on the number of data entries to any significant extent.
    DOE also disagrees that its proposed measurement intervals would 
require costly upgrades to laboratory facilities. Given that DOE's 
proposed measurement interval was only slightly different from the 
current requirement included in Exhibit G.1 of ANSI Z21.10.3-2011 
(which DOE currently incorporates by reference for the thermal 
efficiency test)--30 seconds vs. 1 minute--DOE does not believe that 
this provision will require any upgrades. The duration of the standby 
loss test exceeds 24 hours and can reach up to 48 hours; therefore, DOE 
does not believe that any manufacturers are performing this test 
without an automated data acquisition system. The one-time cost of a 
data acquisition system would likely be much less than the recurring 
labor costs of having a lab technician constantly monitor and record 
measurements every 15 minutes for every standby loss test for up to 48 
hours. Bradford White and Rheem acknowledged that they use data 
acquisition systems in their facilities, and no stakeholders have 
commented to DOE that they do not use data acquisition systems for 
testing of CWH equipment. (Bradford White, Rheem, NOPR Public Meeting 
Transcript, No. 20 at pp. 43-44) Additionally, DOE does not believe 
that increasing the frequency of data collection would require any

[[Page 79274]]

significant upgrades to existing data acquisition systems. Rather, DOE 
believes that changing the measurement frequency would require a simple 
one-time software change and that the additional amount of data 
collected could be stored inexpensively given the low cost of computer 
storage. Additionally, DOE is not adopting any requirements in this 
final rule that would require measurement with a data acquisition 
system other than time and temperature.
    DOE believes that more frequent data collection allows the capture 
of any variation in parameters that might affect the measured 
efficiency of CWH equipment. If variation is detected such that a 
parameter does not meet the DOE test procedure requirements, then DOE 
believes that re-running the test would be warranted. However, DOE 
acknowledges that there is a possibility that there could be momentary 
fluctuations in ambient conditions and/or water temperatures that do 
not have a significant effect on efficiency. In such a case, a single 
data point out of the allowable range of the DOE test procedure could 
require a test to be re-run. The likelihood of such a momentary 
fluctuation being captured in a test data point is directly 
proportional to the frequency of data collection. For this reason, DOE 
is not adopting the proposed 30-second data collection intervals and is 
instead maintaining the existing 1-minute data collection interval 
requirement for the thermal efficiency test and decreasing the required 
data collection interval for the standby loss test from 15 minutes to 1 
minute. For the thermal efficiency test, the 1-minute time interval 
applies to the measurement of (1) ambient room temperature, (2) test 
air temperature, (3) supply water temperature, and (4) outlet water 
temperature. For the standby loss test, the 1-minute time interval 
applies to the measurement of (1) ambient room temperature, (2) test 
air temperature, (3) mean tank temperature for storage water heaters 
and storage type-instantaneous water heaters, and (4) outlet water 
temperature for instantaneous water heaters and hot water supply 
boilers other than storage type-instantaneous water heaters. DOE 
concludes that these changes to the data recording intervals improve 
repeatability, while maintaining consistency with the test method in 
ANSI Z21.10.3-2015.
    This 1-minute data collection interval is consistent with the 
required 1-minute measurement interval for inlet and outlet water 
temperatures included in the 2011 and 2015 versions of ANSI Z21.10.3. 
For the standby loss test, DOE believes that the benefits of finer 
granularity in data collected from 1-minute intervals instead of 15-
minute intervals will provide confirmation that variation in ambient 
conditions does not occur during the test that could have a significant 
impact on the measured standby loss. DOE believes that this benefit 
outweighs any potential burden that might occur from the possibility of 
having to re-run a test because momentary fluctuations of ambient 
conditions out of tolerance were captured that would not affect the 
measured standby loss.
    As discussed in sections III.F.1 and III.L of this final rule, DOE 
is also adopting requirements that the gas consumption be measured at 
10-minute intervals during the steady-state verification period and 
thermal efficiency test. These gas consumption measurements are used to 
determine fuel input rate. As discussed in section III.F.1 of this 
final rule, DOE does not expect its requirements that gas consumption 
be measured at 10-minute intervals during the steady-state verification 
period and thermal efficiency test to impose any significant burden on 
manufacturers.

C. Test Set-Up for Storage and Storage-Type Instantaneous Water Heaters

    DOE's current test procedure for CWH equipment incorporates by 
reference the requirement in Exhibit G.1 of ANSI Z21.10.3-2011 that the 
inlet and outlet piping be immediately turned vertically downward from 
the connections on a tank-type water heater to form heat traps, and 
that the thermocouples for measuring supply and outlet water 
temperatures be installed before the inlet heat trap piping and after 
the outlet heat trap piping. DOE noted in the May 2016 NOPR that the 
absence of a clearly defined location for the thermocouples could 
contribute to variability in the test results. As a result, DOE 
proposed particular locations for installing the supply and outlet 
water temperature sensors based on piping distance from the water 
heater connections. Specifically, DOE proposed that the sensors be 
placed after a total vertical piping distance of 24 inches and total 
horizontal piping that is (1) two inches plus the piping distance 
between the water connection and the edge of the water heater with top 
and bottom openings for water connections and (2) 6 inches for 
horizontal opening water connections. DOE also provided separate 
figures for each configuration of storage water heaters (i.e., top, 
bottom and horizontal opening water connections) and included them in 
the proposed appendix A to subpart G of part 431 of the regulatory text 
of the May 2016 NOPR. 81 FR 28588, 28598-28599 (May 9, 2016).
    Rheem stated that it agrees with the standardization of the 
location of temperature measurements, but disagrees with the distance 
of 24 inches for measuring the water temperature. Rheem argued that 
having an outlet water temperature measured at the proposed distance 
would result in inclusion of the piping losses, which may also differ 
between the piping configurations and outlet water temperature sensor 
locations adopted by each lab, and recommended that the water 
temperature for storage water heaters should be measured at a distance 
of 5 inches away from the water heater to achieve comparable results 
with instantaneous water heaters. Last, Rheem stated that the proposed 
inlet water temperature location for CWH equipment with water 
connections on the side of the tank is not feasible in the case of some 
of its models that have inlet water openings only 6 inches above the 
floor. (Rheem, No. 34 at pp. 6-7)
    DOE agrees with Rheem that the total piping distance from the water 
heater to the temperature sensors (particularly the outlet water 
temperature) should be consistent between both storage type and 
instantaneous type water heaters, so that any piping losses are 
comparable. In the May 2016 NOPR, DOE proposed to specify the 
measurement location for outlet water temperature at 5 inches from the 
enclosure for instantaneous water heaters, because that measurement was 
proposed to be used for both outlet water temperature for the thermal 
efficiency test and to approximate the water temperature of stored 
water within the heat exchanger for the standby loss test. 81 FR 28588, 
28613-28615 (May 9, 2016) Thus, for the standby loss test, it was 
important for that measurement to occur close to the unit. However, as 
discussed in section III.I.1, in this final rule, DOE is adopting a 
separate temperature measurement location for measuring water to 
approximate the water temperature within the heat exchanger for the 
standby loss test, and for measuring the outlet water temperature for 
the thermal efficiency test. As a result, in section III.I.1 of this 
final rule, DOE has modified the test set-up for instantaneous water 
heaters and hot water supply boilers so that: (1) Outlet water 
temperature for the thermal efficiency test is measured at the second 
elbow in the outlet water piping; (2) heat exchanger outlet water 
temperature measured for the standby loss test is within one inch of 
the outlet water port

[[Page 79275]]

(inside or outside); and (3) total piping distance between the water 
heater and supply and outlet water temperature sensors is consistent 
with that specified in the test set-up for water heaters with 
horizontal opening water connections. Rather than change the location 
of the temperature measurements for storage water heaters, as suggested 
by Rheem, DOE changed the measurement location for instantaneous water 
heaters. By using separate temperature sensors to measure the outlet 
water temperature for the standby loss test (within one inch of outlet) 
and the thermal efficiency test (at the second elbow), it is no longer 
necessary to have a temperature sensor for the outlet water temperature 
that is as close as possible to the water heater. Further, the 
additional piping length allows installation of two elbows in the 
piping and the measurement of the water temperature downstream (for 
outlet) and upstream (for supply) of the heat traps that are required 
for the test set-up. Installing the outlet water temperature sensor for 
the thermal efficiency test at the second elbow ensures that the water 
flow will be well mixed, resulting in more accurate temperature 
readings (as recommended by stakeholders). For a detailed explanation 
on test set up for instantaneous water heaters and hot water supply 
boilers and DOE's responses to public comments, see section III.I of 
this final rule.
    With regard to Rheem's concerns about piping losses if the outlet 
water temperature is measured at a piping distance of 30 inches away 
from the water heater, DOE notes that the current and the proposed test 
set up both require the water piping to be insulated up to a distance 
of 4 feet from the water connections, which should minimize piping 
losses. In addition, water heaters with large pipe diameters may not be 
able to install outlet water temperature sensors with two elbows in the 
piping (to yield sufficient flow mixing) at 5 inches from the water 
heater.
    DOE also considered Rheem's other comments on the inability of 
certain water heater models with horizontal water connections, to meet 
the vertical piping distance of 24 inches as proposed in May 2016 NOPR 
for the inlet water connection. To address this issue, DOE is adopting 
a requirement that the vertical piping distance be 24 inches, unless 24 
inches is not possible, in which case the maximum possible distance for 
a given water heater model must be used.
    Based on the foregoing, DOE is adopting the test set-ups shown in 
Figures III.1, III.2, and III.3 for gas-fired and oil-fired storage 
water heaters and gas-fired and oil-fired storage-type instantaneous 
water heaters. In addition, DOE uses very similar test set-ups for 
other types of CWH equipment. Specifically, as discussed in section 
III.I.5, the set-up for instantaneous water heaters and hot water 
supply boilers is the same as shown in Figures III.1, III.2, and III.3, 
except that an outlet water valve and heat exchanger outlet temperature 
sensor are required. DOE has concluded that these changes are 
consistent with the approach in ANSI Z21.10.3-2015, but will provide 
additional specificity and improve test repeatability. The test set-ups 
for electric storage water heaters and storage-type instantaneous water 
heaters are similar to the test set-ups shown in Figures III.1, III.2, 
and III.3, with the only difference being that the outlet water 
temperature sensor is not present. An outlet water temperature sensor 
is not needed for testing electric storage water heaters and storage-
type instantaneous water heaters, because the outlet water temperature 
is not measured during the conduct of the test.
BILLING CODE 6450-01-P

[[Page 79276]]

[GRAPHIC] [TIFF OMITTED] TR10NO16.005


[[Page 79277]]


[GRAPHIC] [TIFF OMITTED] TR10NO16.006

BILLING CODE 6450-01-C

D. Test Method for Unfired Hot Water Storage Tanks

    EPCA defines an ``unfired hot water storage tank'' (UFHWST) as a 
tank used to store water that is heated externally. (42 U.S.C. 
6311(12)(C)) The current Federal standard for this equipment type 
requires a minimum thermal insulation (R-value) of 12.5. 10 CFR 
431.110. DOE defines ``R-value'' as the thermal resistance of 
insulating material as determined based on ASTM Standard Test Method 
C177-97 or ASTM Standard Test Method C518-91 and expressed in 
[deg]F[middot]ft\2\[middot]h/Btu. 10 CFR 431.102. In section III.A.3 of 
this rulemaking, DOE updates references to these standards in its 
definition for ``R-value'' by incorporating by reference ASTM C177-13 
and ASTM C518-15. In the May 2016 NOPR, DOE proposed to adopt a method 
for testing the standby loss for UFHWSTs in lieu of relying on the 
current R-value metric and ASTM standards. DOE received numerous 
comments on this topic, and is still considering those comments. 
Therefore, DOE will address the comments and its proposed test 
procedure for UFHWSTs in a separate rulemaking notice.
    DOE is aware that some manufacturers ship UFHWSTs without 
insulation and that uninsulated UFHWSTs may or may not then be 
insulated on-site. In the May 2016 NOPR, DOE clarified that UFHWSTs 
shipped without insulation are not compliant with the Federal R-value 
standard. 81 FR 28588, 28601-28602 (May 9, 2016). All UFHWSTs must 
either be shipped insulated to the R-value standard or shipped together 
with insulation meeting the R-value standard. Manufacturers of UFHWSTs 
must certify that the insulation meets the R-value standard prescribed 
in 10 CFR 431.110, and this certification must be based on testing 
according to the methods prescribed in the R-value definition. A UFHWST 
manufacturer may demonstrate compliance with the insulation 
requirements either by conducting testing itself or by using test data 
from the insulation material producer. Further, manufacturers of 
UFHWSTs are responsible for retaining records of the underlying test 
data used for certification in accordance with current maintenance of 
records requirements set forth at 10 CFR 429.71.
    In response to the May 2016 NOPR, Bock and Raypak disagreed with 
DOE's clarification that all UFHWSTs must be shipped insulated or with 
insulation. (Bock, No. 19 at p. 2; Raypak, No. 28 at p. 3) Bock argued 
that some units have to be shipped without insulation to allow entry 
into a building, and that requiring shipping with insulation will 
increase expense and in some cases prevent installation. (Bock, No. 19 
at p. 2) Raypak argued that tank insulation might be damaged beyond 
repair in shipping, and then require re-installation of insulation in 
the field. Raypak further suggested that DOE allow UFHWSTs with a 
volume greater than 200 gallons to be field-insulated. (Raypak, No. 28 
at p. 3)
    DOE disagrees with the commenters that manufacturers can distribute 
UFHWSTs in commerce without insulation. The standard, which was set by 
statute, requires a minimum thermal insulation (R-value) of 12.5 for 
UFHWSTs. The covered equipment must be compliant at the time the 
manufacturer distributes it in commerce. See 42 U.S.C. 6316, 6302. 
Therefore, if a manufacturer distributes a UFHWST without insulation, 
the manufacturer has distributed a UFHWST without a minimum thermal 
insulation of 12.5. DOE's interpretation gives manufacturers a great 
deal of flexibility and accommodates commenters' concerns that 
insulation already wrapped on the UFHWST may be damaged during shipment 
or that insulated UFHWSTs may not fit through the entryway to some 
buildings, as manufacturers can either ship the tank already wrapped in 
insulation or with insulation provided. Therefore, if there are any 
UFHWSTs that cannot be shipped already insulated, or if there are 
concerns of damage of insulation in shipping, then the insulation 
shipped with the unit can be applied upon

[[Page 79278]]

installation. All UFHWSTs of all storage volumes must satisfy this 
requirement. Accordingly, in this final rule, DOE reiterates that all 
UFHWSTs must be shipped insulated or with insulation such that the 
installed UFHWST will meet the minimum standard.

E. Setting the Tank Thermostat for Storage and Storage-Type 
Instantaneous Water Heaters

    DOE's test procedure for measuring the energy efficiency of CWH 
equipment currently requires that the thermostat be set to achieve 
specific conditions for the mean tank temperature before the test may 
begin. In particular, section g of Exhibit G.1 of ANSI Z21.10.3-2011 
(which is currently incorporated by reference into the DOE test 
procedure) requires that before starting testing, the thermostat 
setting must be adjusted such that, when starting with the water in the 
system at 70 [deg]F  2 [deg]F, the maximum mean tank 
temperature would be 140 [deg]F  5 [deg]F after the 
thermostat reduces the gas supply to a minimum.
1. Gas-Fired and Oil-Fired Storage Water Heaters
    DOE understands that some units may have difficulty achieving the 
current mean tank temperature requirement (e.g., condensing water 
heaters), and in the May 2016 NOPR, DOE proposed to modify its 
requirements for setting the tank thermostat. 81 FR 28588, 28604 (May 
9, 2016). Specifically, DOE proposed to modify the thermal efficiency 
and standby loss test procedures for gas-fired and oil-fired storage 
water heaters and storage-type instantaneous water heaters to require 
that before starting the required soak-in period, the thermostat 
setting be adjusted such that, when starting with the water in the 
system at 70  2 [deg]F, the maximum outlet water 
temperature will be 140 [deg]F  5 [deg]F after the 
thermostat reduces the gas supply to a minimum.
    In response to the May 2016 NOPR, DOE received comments from 
several interested parties. Joint Advocates and Rheem agreed with 
changing from a mean tank temperature requirement to an outlet water 
temperature requirement for fossil fuel-fired storage water heaters. 
(Joint Advocates, No. 32 at p. 2; Rheem, No. 34 at p. 8) However, Rheem 
also stated that outlet water temperature is a poor indicator of 
standby loss, and that mean tank temperature should be used to 
determine heat loss. (Rheem, No. 34 at p. 8) AHRI stated that 
measurement of outlet water temperature will not work for setting the 
tank thermostat if measured more than 2 feet downstream of the water 
heater outlet because water is not flowing when setting the thermostat. 
Instead, AHRI suggested that the six tank temperature sensors be 
installed in the tank at the beginning of the test, as is currently 
required in ANSI Z21.10.3-2015, and that the tank thermostat be set 
based on the reading from the topmost tank temperature sensor used to 
calculate mean tank temperature. (AHRI, No. 26 at p. 8) A.O. Smith 
stated that, for the thermal efficiency test, setting the tank 
thermostat is irrelevant as long as the water heater is firing at full 
input rate and meeting the outlet water temperature requirement. A.O. 
Smith further suggested that, in order to measure the outlet water 
temperature for standby loss, the measurement location needs to be 
inside the tank within one inch of the tank outlet. (A.O. Smith, No. 27 
at p. 5) Bradford White stated that the same thermostat setting should 
be used for both thermal efficiency and standby loss tests, and 
requested clarification on DOE's proposal, stating that the language in 
the NOPR preamble and the proposed appendix A in the NOPR regulatory 
text were not consistent. (Bradford White, No. 21 at p. 8)
    DOE agrees with A.O. Smith that, for an outlet temperature 
requirement, as opposed to a mean tank temperature requirement, setting 
the tank thermostat for the thermal efficiency test is irrelevant as 
long as the water heater is firing continuously at full firing rate and 
all the specifications required for the steady-state verification 
period, including the outlet water temperature requirement, are met. 
However, because the thermostat setting does not affect the operation 
of the water heater during the thermal efficiency test as long as the 
burner is firing continuously at full firing rate, the thermostat 
setting used in the thermal efficiency test does not necessarily 
provide an outlet water temperature of 140 [deg]F  5 [deg]F 
when water is not flowing through the water heater. In order to ensure 
that this outlet water temperature requirement is met, DOE believes 
that the thermostat setting needs to be set such that the maximum 
outlet water temperature after cut-out is 140 [deg]F  5 
[deg]F before beginning the standby loss test.
    While the thermostat settings used during the thermal efficiency 
test do not affect the test results so long as the burner fires 
continuously at full firing rate, DOE understands that the standby loss 
test is often performed directly after the thermal efficiency test. In 
this final rule, DOE is adopting provisions such that a soak-in period 
is not required in between the thermal efficiency and standby loss 
tests, if no settings on the water heaters are changed and the water 
heater is not turned off. However, setting the tank thermostat between 
the thermal efficiency and standby loss tests would inherently require 
changing settings on the water heater, unless the thermostat was 
already set to achieve the required outlet water temperature after cut-
out of 140 [deg]F  5 [deg]F. Therefore, DOE believes that 
the tank thermostat must be set to meet the outlet water temperature 
requirement before the thermal efficiency test. DOE notes that 
requiring the tank thermostat to be set prior to the thermal efficiency 
test is consistent with DOE's current test procedure, DOE's proposal in 
the May 2016 NOPR, and with AHRI's comment.
    DOE agrees with AHRI and A.O. Smith that it would be difficult to 
set the tank thermostat without water flowing through the water heater 
such that the outlet water temperature after cut-out is 140 [deg]F 
 5 [deg]F, as measured downstream of a heat trap in the 
outlet water piping. Additionally, DOE believes that the tank 
thermostat must be set without water flowing through the water heater; 
otherwise, both the tank thermostat and water flow rate would affect 
the measured outlet water temperature, and the thermostat settings 
obtained might not ensure that the outlet water temperature requirement 
is met without water flowing. Therefore, DOE believes that the 
thermostat should be set based on the reading of a temperature sensor 
located inside the tank. However, commenters disagreed on the location 
of measurement, with AHRI suggesting using the temperature recorded at 
the topmost temperature sensor in the tank that is used for measurement 
of mean tank temperature, while A.O. Smith suggested the placement of a 
temperature sensor inside the tank within 1 inch of the water heater 
outlet. While a temperature sensor within one inch of the water heater 
outlet is closer to the temperature of the water delivered than is the 
topmost temperature sensor used for mean tank temperature calculation, 
the difference between these temperatures is likely insignificant, and 
therefore, the placement of an additional temperature sensor in the 
tank for the sole purpose of setting the tank thermostat would be an 
unnecessary burden to manufacturers. Consequently, DOE is adopting a 
requirement that the tank thermostat be set using the reading from the 
topmost tank temperature sensor used to calculate mean tank 
temperature. Based on the above, DOE concludes that there is evidence 
that setting the thermostat according to the mean tank temperature, as 
is done in

[[Page 79279]]

ANSI Z21.10.3-2015, does not provide an accurate reflection of the 
energy efficiency during a representative average use cycle for certain 
equipment. DOE further concludes that the method for setting the 
thermostat adopted in this final rule provides an accurate reflection 
of energy efficiency for all kinds of gas-fired and oil-fired storage 
water heaters on the market. Therefore, DOE concludes that the method 
adopted in this final rule is consistent with the industry standard, 
ANSI Z21.10.3-2015, but provides flexibility so that all designs of 
gas-fired and oil-fired storage water heaters can achieve the 
temperature requirement used for setting the tank thermostat. DOE also 
concludes that the method adopted in this final rule is not unduly 
burdensome to conduct. Therefore, the changes adopted are better 
aligned with the requirements of 42 U.S.C. 6314(a)(2).
    In response to Rheem, while DOE proposed to use outlet water 
temperature for the purpose of setting the tank thermostat for the 
standby loss test, DOE still proposed to use mean tank temperature for 
determining heat loss during the standby loss test. 81 FR 28588, 28604 
(May 9, 2016). In this final rule, DOE is adopting provisions for 
determining heat loss during the standby loss test using mean tank 
temperature, similar to those included in annex E.2 of ANSI Z21.10.3-
2015.
    For gas-fired and oil-fired storage water heaters and storage-type 
instantaneous water heaters, DOE is adopting a requirement that the 
tank thermostat be set prior to the steady-state verification period. 
The thermostat must be set starting with the tank full of water at the 
water supply temperature. The thermostat must be set such that the 
maximum water temperature measured at the topmost tank temperature 
sensor after cut-out (and while water is not flowing through the water 
heater) is 140 [deg]F  5 [deg]F. The thermostat also must 
be set such that with water flowing through the unit continuously, the 
outlet water temperature can be maintained at 70 [deg]F  2 
[deg]F above the supply water temperature, as required during the 
thermal efficiency test. DOE's updated requirements for determining 
steady-state operation for the thermal efficiency test and the steady-
state verification period are discussed in section III.F.1 of this 
final rule. If conducting a standby loss test after a thermal 
efficiency test, the thermostat setting established prior to the 
thermal efficiency test would be used for the standby loss test, and no 
separate procedure would be needed for setting the thermostat. However, 
if the standby loss test is run without a previously run thermal 
efficiency test, the thermostat would need to be set using the same 
procedure as required before the thermal efficiency test, such that the 
maximum top tank sensor water temperature after cut-out is 140 [deg]F 
 5 [deg]F. In this case, the tank thermostat must be set 
prior to the soak-in period.
2. Electric Storage Water Heaters
    DOE proposed to maintain the mean tank temperature requirement for 
the standby loss test for electric storage water heaters, rather than 
adopt an outlet water temperature requirement, because of complications 
involved with setting multiple tank thermostats. 81 FR 28588, 28604 
(May 9, 2016). Electric storage water heaters typically have multiple 
heating elements and thermostats, and each thermostat needs to be set 
prior to beginning the standby loss test. Therefore, DOE tentatively 
determined that electric storage water heaters are not well-suited to 
an outlet water temperature requirement because it is unclear how the 
lower thermostat(s) would be set to achieve a designated outlet water 
temperature. However, DOE proposed to clarify its language specifying 
the method for setting thermostats in an electric storage water heater 
with multiple thermostats. Specifically, DOE proposed to clarify that 
the thermostats are to be set in immediate succession, starting from 
the topmost thermostat. DOE also proposed to clarify that when setting 
each thermostat, the mean tank temperature is calculated using only 
temperature readings measured at locations higher in the tank than the 
heating element corresponding to the thermostat being set, with the 
exception of the bottommost thermostat. Finally, DOE proposed to 
clarify that all thermostats below the thermostat being tested must be 
turned off so that no elements below the thermostat being tested are in 
operation.
    Several commenters agreed with DOE's proposal to maintain the 
existing mean tank temperature requirement for setting the tank 
thermostat for electric storage water heaters. (Bradford White, No. 21 
at p. 8; AHRI, No. 26 at p. 13; A.O. Smith, No. 27 at p. 5; Joint 
Advocates, No. 32 at p. 2; Rheem, No. 34 at p. 9) A.O. Smith also 
agreed with DOE's proposed clarification regarding how to set 
thermostats for electric storage water heaters with multiple 
thermostats. (A.O. Smith, No. 27 at p. 5) However, AHRI, Rheem, and 
Bradford White disagreed with DOE's proposal on how to set thermostats 
for units with multiple thermostats. Specifically, AHRI and Rheem 
suggested that only the topmost and bottommost thermostats be set and 
used for the standby loss test. (AHRI, No. 26 at p. 10; Rheem, No. 24 
at p. 9) AHRI stated that DOE's proposal is unnecessarily burdensome 
and complicated, and that it does not matter how many thermostats and 
associated heating elements are used to meet the mean tank temperature 
requirement for the standby loss test. (AHRI, No. 26 at p. 10) Rheem 
stated that using just the topmost and bottommost thermostats would 
simplify the test and improve consistency among units with different 
thermostat-to-element ratios. Additionally, Rheem commented that not 
all laboratories can supply power greater than 36 kW. (Rheem, No. 24 at 
p. 9) Bradford White recommended that the lowest thermostat be set 
first, and then the next highest, etc. Bradford White also did not 
support DOE's proposal to calculate mean tank temperature with only 
temperature readings measured higher than the heating element 
corresponding to the thermostat being set, with the exception of the 
bottom thermostat. (Bradford White, No. 21 at p. 8)
    After review of stakeholder comments and consultation with several 
independent testing laboratories, DOE agrees with AHRI and Rheem that 
setting all thermostats for the standby loss test for commercial 
electric storage water heaters with multiple thermostats is 
unnecessary. DOE agrees with AHRI that setting fewer thermostats would 
reduce burden to manufacturers and would be unlikely to affect the 
results of the standby loss test, because it is unlikely that more than 
one heating element will experience a call for heat during the standby 
loss test. DOE also notes, based on its assessment of commercial 
electric storage water heaters on the market, most models have banks of 
heating elements grouped together such that a call for heat in the 
lowest thermostat will likely heat the water up to temperature at the 
nearby thermostats as well. Additionally, DOE agrees with Rheem that 
limiting the number of thermostats (and correspondingly the number of 
heating elements) used during the standby loss test may simplify the 
testing of higher input capacity units by limiting the total amperage 
draw to a level that most laboratories would be able to provide.
    DOE believes that the topmost thermostat should be set using mean 
tank temperature calculated only with temperature readings measured at 
locations higher in the tank than the heating element corresponding to 
the thermostat being set. If the water lower in the tank is included in 
the mean tank temperature calculation and has not been previously 
heated by a lower element, as suggested by Bradford

[[Page 79280]]

White, the heating element(s) corresponding to the topmost thermostat 
would have to heat water at the top of the tank to a temperature much 
higher than the required mean tank temperature in order to achieve the 
mean tank temperature requirement.
    In this final rule, DOE is maintaining a mean tank temperature 
requirement for the standby loss test for electric storage water 
heaters. DOE is adopting its proposed requirement that that the tank 
thermostat(s) be set prior to conducting the required soak-in period. 
DOE is also clarifying that the thermostat(s) for electric storage 
water heaters must be set while no water is flowing through the unit. 
DOE is also adopting requirements for setting tank thermostats for 
electric storage water heaters with multiple thermostats. Specifically, 
DOE is specifying that only the topmost and bottommost thermostats be 
set, and that all other thermostats and corresponding elements not 
operate while setting thermostats or during conduct of the standby loss 
test. DOE also specifies that when setting the topmost thermostat, only 
temperature readings measured at locations higher in the tank than the 
heating element corresponding to the topmost thermostat (the lowest 
heating element corresponding to the thermostat if the thermostat 
controls more than one element) should be used to calculate mean tank 
temperature. However, when setting the bottommost thermostat, DOE 
specifies that all temperature readings should be used to calculate 
mean tank temperature. These changes are consistent with the industry 
test method, ANSI Z21.10.3-2015, and simply provide additional detail 
regarding the method for setting the thermostat to improve consistency 
and repeatability.

F. Steady-State Requirements and Soak-In Period

1. Steady-State Verification
    In the May 2016 NOPR, DOE noted that the required three-minute 
period for verifying steady-state operation prior to the thermal 
efficiency test, which is included in Exhibit G.1 of ANSI Z21.10.3-2011 
(currently incorporated by reference in DOE's test procedure), may not 
be sufficiently long. 81 FR 28588, 28601 (May 9, 2016). Additionally, 
DOE noted that the current test procedure does not impose requirements 
for maximum variation in inlet water temperature or water flow rate 
during this period for verifying steady-state operation. Therefore, DOE 
requested information and data that might support a change to the 
provisions for establishing steady-state operation in its test 
procedure.
    In response to the May 2016 NOPR, Bradford White stated that it is 
possible to meet the current criterion of no variation in outlet water 
temperature in excess of 2[emsp14][deg]F over a 3-minute period before 
the water heater has reached steady-state conditions. (Bradford White, 
No. 19 at p. 4) Bradford White and AHRI both commented that 
verification of steady-state operation is an area in which the 
repeatability of the thermal efficiency test can be improved. (Bradford 
White, No. 19 at p. 4; AHRI, No. 26 at p. 9) Bradford White and AHRI 
also suggested that DOE adopt more stringent requirements for 
establishing steady-state operation prior to the thermal efficiency 
test, and included specific guidelines in their comments that they 
recommend DOE implement. Specifically, Bradford White and AHRI 
suggested establishing an hour-long period during which the 
requirements of DOE's current thermal efficiency test procedure would 
have to be met, along with additional requirements for maximum 
variation in: (1) Water flow rate ( 0.25 gallons per minute 
(gpm)); (2) gas higher heating value ( 5 percent, measured 
every 30 minutes); (3) inlet water temperature ( 
0.50[emsp14][deg]F, with respect to the initial reading); and (4) the 
difference between initial and final rise between inlet and outlet 
water temperatures ( 0.50[emsp14][deg]F and  
1[emsp14][deg]F for units with input rates <500,000 Btu/h and >=500,000 
Btu/h, respectively). Bradford White and AHRI further suggested that 
the final 30 minutes of the hour-long period would be used to calculate 
the results of the thermal efficiency test. (Bradford White, No. 19 at 
p. 5; AHRI, No. 26 at pp. 9-10) AHRI also suggested that these 
measurements would be required at least every 60 seconds, except for 
gas higher heating value.
    A.O. Smith commented that while an additional requirement for 
establishing steady-state operation could improve repeatability, it 
would be a new requirement that manufacturers would need to further 
analyze. (A.O. Smith, No. 27 at p. 3) However, A.O. Smith suggested 
revised guidelines for determining steady-state operation in case DOE 
proceeds with such modifications to its test procedure. Specifically, 
A.O. Smith suggested that steady-state be considered established once 
30 minutes of consecutive readings confirm that: (1) Inlet water 
temperature is maintained at 70[emsp14][deg]F  
2[emsp14][deg]F, (2) outlet water temperature is maintained at 
70[emsp14][deg]F  2[emsp14][deg]F above supply water 
temperature, and (3) fuel input rate is within 2 percent of the rated 
input. A. O. Smith argued that the required measurement intervals 
should be one minute for storage-type water heaters but only 15 minutes 
for instantaneous water heaters because instantaneous water heaters do 
not experience a lasting effect from momentary variations in water 
temperature as do storage-type water heaters. (A.O. Smith, No. 27 at 
pp. 3-4)
    Rheem commented that it typically monitors the outlet water 
temperature of storage-type water heaters for at least 20 minutes prior 
to testing but does not record this data. Rheem also stated that it 
typically runs three thermal efficiency tests after steady-state 
conditions are established prior to beginning the thermal efficiency 
test for which data are recorded. Additionally, Rheem asserted that 
instantaneous water heaters only require 5 minutes of operation before 
steady-state conditions are reached, and that different steady-state 
verification requirements may be warranted for different classes of CWH 
equipment. (Rheem, No. 34 at p. 7)
    DOE agrees with the commenters that the guidelines for establishing 
steady-state operation that were suggested by Bradford White and AHRI 
would improve test repeatability. Specifically, DOE agrees with these 
commenters that extending the duration of the steady-state verification 
period from 3 minutes to 30 minutes prior to the start of the 30 minute 
period for the thermal efficiency test (for which steady-state 
conditions must also be maintained, equating to a total of one hour of 
continuous steady-state operation), and adding additional requirements 
for verification would improve the repeatability of the test. DOE notes 
these guidelines were suggested by a trade organization that represents 
manufacturers that produce over 90 percent of CWH equipment sold in the 
United States, indicating that the need for adopting these guidelines 
is widely understood across the industry. Additionally, Bradford White 
noted that its suggested guidelines for determining steady-state 
operation were developed by an industry working group, and that AHRI 
plans to adopt these test guidelines. (Bradford White, No. 21 at p. 5) 
Therefore, DOE concludes that the modifications to DOE's steady-state 
verification procedures adopted in this final rule do not require 
further analysis and comment from manufacturers, as suggested by A.O. 
Smith, because DOE's adopted requirements contain only minor deviations 
from the guidelines suggested by Bradford White and AHRI. However, DOE 
is open to stakeholder feedback regarding these procedural 
modifications related to establishment of steady-state operation, 
including

[[Page 79281]]

experiences prior to the compliance date, and the Department would 
consider addressing any potential issues in a future test procedure 
rulemaking or guidance, as necessary.
    DOE agrees with all of the conditions specified in the steady-state 
requirements recommended by Bradford White and AHRI, except for the 
requirement that there be no variation in the higher heating value of 
greater than  5 percent. DOE notes that AHRI and Bradford 
White recommended requirements for steady-state verification that 
include a maximum variation on the fuel higher heating value, while the 
guidelines suggested by A.O. Smith instead include a requirement that 
the fuel input rate be maintained within 2 percent of the rated input. 
While DOE recognizes that restricting variation in fuel higher heating 
value ensures consistency in the composition of fuel consumed (e.g., 
ensuring steady-state operation in the case that the fuel source is 
changed during the test), DOE believes that restricting variation on 
fuel input rate would be more effective in terms of ensuring that 
steady-state operation is reached. Variation in fuel higher heating 
value is reflected in measurement of fuel input rate, along with 
variation in gas consumption. Additionally, section 2.3.3 of ANSI 
Z21.10.3-2011, which is referenced in exhibit G.1 of ANSI Z21.10.3-2011 
(referenced in DOE's current test procedure), specifies that the burner 
shall be adjusted to achieve a measured input within  2 
percent of the manufacturer's rated input 15 minutes after being placed 
in operation from a room temperature start. Therefore, DOE believes 
that including a similar requirement for restricting variation in fuel 
input rate when verifying steady-state operation is consistent with 
DOE's current test procedure and the industry consensus test standard 
(ANSI Z21.10.3).
    DOE does not expect a requirement to measure fuel input rate during 
the steady-state verification period and thermal efficiency test to 
impose any significant burden to manufacturers. As discussed in section 
III.F.2 of this final rule, no commenters suggested that DOE's proposed 
clarification that full firing rate must be maintained throughout the 
thermal efficiency test would be burdensome or difficult to achieve. 
Determination of fuel input rate for each 10-minute interval simply 
requires recording the fuel consumption every ten minutes.
    Consequently, DOE is adopting the requirements for determining that 
steady-state operation has been achieved, as recommended by AHRI and 
Bradford White with one modification. Specifically, DOE is declining 
AHRI and Bradford White's suggestion of a requirement for maintaining 
the fuel higher heating value within  5 percent in favor of 
adopting A.O. Smith's suggestion of a requirement to maintain the fuel 
input rate within  2 percent. Under the test procedure 
adopted in this final rule, the thermal efficiency test will be 
complete when there is a continuous, one-hour-long period (comprising 
the 30-minute ``steady-state verification period'' and 30-minute 
``thermal efficiency test'') meeting the following requirements: (1) 
Outlet water temperature is maintained at 70 [deg]F  2 
[deg]F above supply water temperature, (2) water flow variation is no 
greater than  0.25 gpm from the initial value, (3) fuel 
input rate is maintained within 2 percent of the rated input certified 
by the manufacturer, (4) the supply water temperature (or inlet water 
temperature if a recirculating loop is used for instantaneous water 
heaters and hot water supply boilers) is within  0.5 [deg]F 
of its initial reading, and (5) the rise between the supply water 
temperature (or inlet water temperature if a recirculating loop is used 
for instantaneous water heaters and hot water supply boilers) and 
outlet water temperatures is within  0.50 [deg]F of its 
initial value for the duration of the one-hour-long period for units 
with rated input less than 500,000 Btu/h, and within  1 
[deg]F of its initial value for units with rated input greater than or 
equal to 500,000 Btu/h. The final 30 minutes will be used to calculate 
thermal efficiency. DOE concludes that the method for determining 
steady-state operation adopted in this final rule is consistent with 
the industry test standard, ANSI Z21.10.3-2015, but provides more 
stringent requirements to improve consistency. Based on the comments 
received from stakeholders and the foregoing discussion, DOE concludes 
that the adopted method will produce results which better reflect the 
energy efficiency of CWH equipment during a representative average use 
cycle and will not be unduly burdensome to conduct, as required by 
EPCA. (42 U.S.C. 6314(a)(2))
    In response to A.O. Smith's suggestion that DOE increase the 
measurement interval for instantaneous type water heaters, DOE 
disagrees and is maintaining 1-minute measurement intervals for the 
thermal efficiency test as currently included in DOE's test procedure. 
This interval applies to the new requirements for determining steady-
state operation (adopted from the guidelines suggested by Bradford 
White and AHRI), except for fuel input rate, which has a 10-minute 
measurement interval. While DOE acknowledges it is possible that burner 
fluctuations may not have as much of a lasting effect on instantaneous 
water heaters (other than storage-type instantaneous water heaters) as 
suggested by A.O. Smith, DOE is not adopting a longer measurement 
interval for instantaneous water heaters than for storage water 
heaters. DOE believes that the 1-minute measurement interval included 
in DOE's current test procedure is appropriate for both storage water 
heaters and instantaneous water heaters, and that it is appropriate and 
not significantly burdensome to manufacturers to extend this 
measurement interval to the measurements taken during the steady-state 
verification period prior to the thermal efficiency test. DOE notes 
that this one-minute interval was included in the suggestion for 
determining steady-state operation from both Bradford White and AHRI. 
Measurement intervals for both the thermal efficiency and standby loss 
tests are further discussed in section III.B.5 of this final rule.
    DOE disagrees with Rheem's suggestion that separate requirements 
may be warranted for verifying steady-state operation for instantaneous 
water heaters and storage water heaters, and is adopting the same 
requirements for both kinds of CWH equipment. Many storage water 
heaters, particularly those with a low input-volume ratio, may require 
a significant amount of time before steady-state conditions are reached 
and measurements can begin constituting the steady-state verification 
period. In contrast, instantaneous water heaters, with a much higher 
input-volume ratio, may reach steady-state conditions very quickly, and 
it may only take a short time after beginning water heater operation 
before measurements can be included in the steady-state verification 
period. However, DOE is not adopting any provisions or requirements 
regarding the duration of the period during which CWH equipment warms 
up to reach steady-state conditions. Nonetheless, DOE continues to 
believe that a 30-minute period for verifying steady-state operation is 
appropriate for both storage water heaters and instantaneous water 
heaters, and that the duration of this period should not depend upon 
the time it takes for the water heater to warm up. Thus, DOE is not 
adopting different verification requirements for instantaneous water 
heaters, as suggested by Rheem.

[[Page 79282]]

2. Clarifying Statements
    DOE's current thermal efficiency test procedure for gas-fired and 
oil-fired CWH equipment, which incorporates by reference Exhibit G.1 of 
ANSI Z21.10.3-2011, requires the water heater to achieve steady-state 
conditions prior to beginning measurements for the thermal efficiency 
test. Specifically, the test procedure requires the outlet water 
temperature to be maintained at 70 [deg]F  2 [deg]F above 
the supply water temperature, with no variation in excess of 2 [deg]F 
over a 3 minute period. However, DOE's current test procedure does not 
specify that this outlet water temperature requirement must be 
maintained throughout the thermal efficiency test.
    In the May 2016 NOPR, DOE proposed adding clarifying statements to 
its test procedure regarding steady-state operation. Specifically, DOE 
proposed to require that the test entity must maintain the outlet water 
temperature at 70 [deg]F  2 [deg]F above the supply water 
temperature and ensure the burner fires continuously at the full firing 
rate (i.e., no modulation or cut-outs) for the entire duration of the 
thermal efficiency test. Further, DOE proposed to clarify that once 
steady-state operation is achieved, as determined by no variation of 
the outlet water temperature in excess of 2 [deg]F over a 3-minute 
period, no settings on the water heating equipment may be changed until 
measurements for the thermal efficiency test are finished. DOE also 
proposed a similar clarification for the standby loss test for CWH 
equipment other than flow-activated instantaneous water heaters, 
requiring that after the first cut-out before beginning the standby 
loss test, no settings may be changed on the water heater until 
measurements for the standby loss test are finished. 81 FR 28588, 
28604-28605 (May 9, 2016).
    In response to the May 2016 NOPR, several commenters agreed with 
DOE's proposed clarifications. (Bock, No. 19 at p. 2; Bradford White, 
No. 21 at p. 8, A.O. Smith, No. 27 at p. 6; Rheem, No. 34 at p. 9) 
Bradford White further noted that it believes that the content of DOE's 
clarifying statements are already understood and common industry 
practice. However, Bradford White noted that it did not agree with the 
3-minute period for determining steady-state operation. (Bradford 
White, No. 21 at p. 8)
    The provisions for establishing steady-state operation prior to the 
thermal efficiency test that DOE is adopting in this final rule (as 
discussed in section III.F.1 of this final rule) include, among other 
requirements, that the following conditions be maintained throughout 
the test: (1) The specified outlet water temperature, and (2) the fuel 
input rate within  2 percent of the manufacturer's rated 
input. This is in contrast to the existing requirement that there be no 
variation in outlet water temperature in excess of 2 [deg]F over a 3-
minute period prior to beginning the test. Therefore, additional 
clarifying statements addressing these conditions during the thermal 
efficiency test are no longer necessary, as they now must be maintained 
throughout the duration of the test. However, DOE is adopting its 
proposed provisions requiring that no settings may be changed on the 
CWH equipment being tested: (1) Once the steady-state conditions are 
established during the steady-state verification test and until the 
thermal efficiency test is completed; and (2) after the first cut-out 
before beginning the standby loss test until the measurements of the 
standby loss test are completed (for all CWH equipment, except for 
flow-activated instantaneous water heaters and externally 
thermostatically-activated instantaneous water heaters). (For more 
information on the standby loss test procedure adopted for flow-
activated and externally thermostatically-activated instantaneous water 
heaters, see section III.H.3 of this final rule.) As noted above by 
commenters, these requirements to leave the settings on CWH equipment 
unchanged during certain portions of testing are already generally 
understood and common industry practice. DOE is adding these 
requirements to clarify the industry test method, and, therefore, 
concludes that these changes are consistent with ANSI Z21.10.3-2015.
3. Soak-In Period
    DOE's current thermal efficiency test procedure for gas-fired and 
oil-fired CWH equipment, which incorporates by reference Exhibit G.1 of 
ANSI Z21.10.3-2011, requires the water heater to achieve steady-state 
conditions prior to beginning measurements for the thermal efficiency 
test. Specifically, the test procedure requires the outlet water 
temperature to be maintained at 70 [deg]F  2 [deg]F above 
the supply water temperature, with no variation in excess of 2 [deg]F 
over a 3-minute period. DOE's current standby loss test procedure for 
gas-fired and oil-fired CWH equipment, which incorporates by reference 
Exhibit G.2 of ANSI Z21.10.3-2011, requires the water heater to reach a 
mean tank temperature of 140 [deg]F and remain in standby mode after 
the first cut-out until the next cut-out before measurements for the 
standby loss test begin. However, as discussed in the May 2016 NOPR, 
DOE thought it possible that these provisions for both tests might be 
insufficient for ensuring that the tank insulation is fully heated 
before beginning test measurements.
    In the May 2016 NOPR, DOE proposed to require a soak-in period 
prior to beginning the thermal efficiency and standby loss tests, in 
which the water heater would remain idle (i.e., no water draws) for at 
least 12 hours with thermostat(s) maintained at settings that would 
achieve the required water temperature. 81 FR 28588, 28598 (May 9, 
2016). However, DOE proposed not requiring a soak-in period prior to 
the beginning of an efficiency test (i.e., thermal efficiency or 
standby loss) if no settings on the water heater were changed and the 
water heater had not been turned off since the end of a previously run 
efficiency test.
    In response to the May 2016 NOPR, A.O. Smith stated that all 
proposed requirements for soak-in periods are unnecessary and would not 
improve test accuracy or repeatability, given the requirements for 
establishing steady-state operation. (A.O. Smith, No. 27 at p. 17) 
Several commenters stated that a soak-in period is unnecessary before a 
thermal efficiency test because DOE's test procedure requires that 
steady-state operation be reached prior to beginning measurements. 
(Bradford White, No. 19 at p. 4; AHRI, No. 26 at pp. 9-10; Raypak, No. 
28 at p. 6; Rheem, No. 34 at p. 6) However, Bradford White, AHRI, and 
Raypak indicated that the soak-in period would be useful prior to a 
thermal efficiency test if the water heater were not stored in a 
conditioned space (i.e., maintained at 75 [deg]F  10 [deg]F 
according to Bradford White, maintained at temperature above freezing 
according to Raypak, and unspecified according to AHRI). (Bradford 
White, No. 19 at p. 4; AHRI, No. 26 at pp. 9-10; Raypak, No. 28 at p. 
6) Bradford White and AHRI also argued that a soak-in period should 
only be required before a standby loss test if the test is not begun 
within 3 hours of the end of a thermal efficiency test. (Bradford 
White, No. 19 at p. 4; AHRI, No. 26 at pp. 9-10) Raypak indicated that 
a soak-in period should only be required before a standby loss test if 
the water heater is not stored in a conditioned space. (Raypak, No. 28 
at p. 6) Rheem stated that a soak-in period of 12 hours is sufficiently 
long before conducting a standby loss test without a previously run 
thermal efficiency test. (Rheem, No. 34 at p. 6)
    A.O. Smith argued that while not requiring human interaction, a 
soak-in period would be burdensome to

[[Page 79283]]

manufacturers because it would require lab space to be occupied and 
certain environmental conditions to be monitored and maintained. (A.O. 
Smith, No. 27 at p. 17) Rheem stated that the soak-in period would 
place an additional burden on manufacturers in terms of time, 
resources, and laboratory space, if required when a thermal efficiency 
test is performed in conjunction with a standby loss test. (Rheem, No. 
34 at p. 6)
    DOE acknowledges that a soak-in period would not be warranted 
before a thermal efficiency test if steady-state operation is assured 
prior to beginning the test. Given the more stringent provisions for 
determining steady-state operation that DOE is adopting in this final 
rule (discussed in section III.F.1), DOE agrees with commenters that a 
soak-in period is not needed before the thermal efficiency test, and is 
not adopting this requirement. While several commenters indicated that 
a soak-in period might be helpful if the water heater were not stored 
in a conditioned space, DOE believes that in this case, the water 
heater would simply take longer to reach the required steady-state 
conditions before beginning the thermal efficiency test, and that an 
additional soak-in period would not be necessary.
    DOE believes that a soak-in period would improve test repeatability 
for the standby loss test if a thermal efficiency test were not 
previously conducted. In the May 2016 NOPR, DOE also proposed that a 
soak-in period be required if any settings on the water heater had been 
changed, or if the water heater had been turned off since the end of a 
previously run efficiency test. 81 FR 28588, 28598 (May 9, 2016). 
However, Bradford White and AHRI indicated that a soak-in period should 
only be required before the standby loss test if the standby loss test 
does not begin within three hours of the end of a previously run 
thermal efficiency test. (Bradford White, No. 19 at p. 4; AHRI, No. 26 
at p. 9)
    DOE disagrees with the suggestion that a soak-in period would not 
be necessary if a water heater were turned off after a thermal 
efficiency test but for three hours or less before beginning the 
standby loss test. DOE believes that the water heater should be turned 
on at all times between the end of the thermal efficiency test and the 
beginning of the standby loss test to ensure that the thermal 
equilibrium within the tank insulation, or ``soaking in,'' achieved 
during the thermal efficiency test is not lost before starting the 
standby loss test. DOE notes that water heaters likely vary 
significantly in the time required after ending the thermal efficiency 
test before the burner cuts in again. This variation includes factors 
such as storage volume, tank heat losses, and thermostat control 
algorithms. For certain water heaters, this time may even exceed three 
hours, in which case it would not matter if the water heater were 
turned on or off during this period. However, in other cases, the 
thermal equilibrium of the tank may be lost if the water heater is 
turned off between tests. A decrease in the insulation temperature 
between tests might require additional energy consumption to reheat the 
insulation during the standby loss test, which would result in higher 
calculated values of standby loss.
    DOE also believes that a soak-in period requirement will improve 
the repeatability of the standby loss test for electric storage water 
heaters. Electric storage water heaters do not have a thermal 
efficiency test, so unless multiple standby loss tests are run 
consecutively, the soak-in period will ensure that the tank insulation 
has reached thermal equilibrium before measurements for the standby 
loss test begin. Therefore, to improve repeatability of the standby 
loss test for storage water heaters and storage-type instantaneous 
water heaters, DOE is adopting a requirement that a soak-in period of 
12 hours be conducted before the standby loss test unless no settings 
on the water heater have been changed and the water heater has not been 
turned off since the end of a previously run efficiency test. DOE 
concludes that adding requirements for the soak-in period (when 
required) will improve the repeatability of the test result, but is 
consistent with ANSI Z21.10.3-2015.
    The provisions DOE is adopting that specify when a 12-hour soak-in 
period is required prior to the standby loss test (i.e., required 
unless no settings on the water heater have been changed and the water 
heater has not been turned off since the end of a previously run 
efficiency test) allow flexibility for the manufacturer or testing 
agency. After completion of the thermal efficiency test, as long as the 
water heater stays turned on and no settings are changed, the 
laboratory technician may choose to begin the standby loss test 
immediately, or allow the tank to soak in longer before beginning the 
standby loss test.

G. Definitions for Certain Consumer Water Heaters and Commercial Water 
Heating Equipment

1. Consumer Water Heaters
    A statutory definition for consumer ``water heater'' was added to 
EPCA by the National Appliance Energy Conservation Act of 1987 (NAECA; 
Pub. L. 100-12, March 17, 1987), which specifies input ratings at or 
below which water heaters are to be classified as consumer water 
heaters (e.g., 75,000 Btu/h for gas-fired storage water heaters; 12 kW 
for electric storage water heaters and electric instantaneous water 
heaters; 210,000 Btu/h for oil-fired instantaneous water heaters). (42 
U.S.C. 6291(27)) NAECA also established standards for gas-fired 
consumer water heaters, oil-fired consumer water heaters, and electric 
consumer water heaters. (42 U.S.C. 6295(e)(1))
    DOE restated the statutory definition of ``water heater'' in the 
appliance standards regulations applicable to consumer products at 10 
CFR 430.2. In addition to adopting EPCA's definition of ``water 
heater'' for standards applicable to consumer products, DOE defined a 
variety of terms in the test procedure provisions applicable to 
consumer water heaters to help specify the test procedure provisions 
applicable to specific kinds of water heaters (e.g., ``gas 
instantaneous water heater'' and ``electric storage water heater''). 55 
FR 42162, 42169 (October 17, 1990). These test procedure definitions 
included provisions related to water temperature design characteristics 
and rated storage volume. The standards at 10 CFR 430.32 and the 
``water heater'' definition at 10 CFR 430.2 did not include any such 
limitations.
    In an effort to consolidate all relevant definitions in 10 CFR 
430.2, DOE removed the definitions for specific kinds of consumer water 
heaters from its test method at appendix E to subpart B of part 430 
(i.e., ``electric heat pump water heater,'' ``electric storage water 
heater,'' ``gas-fired instantaneous water heater,'' ``gas-fired storage 
water heater,'' and ``oil-fired storage water heater'') and placed 
these definitions in the general definition section at 10 CFR 430.2, 
along with newly established definitions for ``gas-fired heat pump 
water heaters,'' ``oil-fired instantaneous water heater,'' and 
``electric instantaneous water heater.'' 79 FR 40542, 40549, 40566-
40567 (July 11, 2014). The reorganization of the existing definitions 
and the newly established definitions became effective on July 13, 
2015, and these definitions excluded products with a rated storage 
capacity greater than 120 gallons and, in some cases, excluded products 
designed to heat and store water at a thermostatically controlled 
temperature greater than 180 [deg]F. 79 FR 40542, 40566-40567 (July 11, 
2014).
    As noted previously, the standards and definition set forth in EPCA 
do not include any limitation related to the water temperature or 
storage capacity.

[[Page 79284]]

Therefore, prior to the effective date of the amendments in the July 
2014 final rule, any product meeting the definition of a ``water 
heater'' as established under EPCA and restated in 10 CFR 430.2 would 
have been subject to the statutory standards applicable to consumer 
water heaters (i.e., water heaters within the input limits established 
under EPCA would have been subject to the standards regardless of the 
water delivery temperature or storage capacity).
    In the May 2016 NOPR, DOE proposed to amend the definitions for 
specific types of consumer water heaters included at 10 CFR 430.2 by 
removing from the definitions the specifications related to the water 
temperature and storage capacity. 81 FR 28588, 28605-28606 (May 9, 
2016). Because a model that would otherwise meet the definition of a 
consumer water heater could not ``become'' commercial as the result of 
the unit's capability of producing water at temperatures above 180 
[deg]F or by having a rated capacity in excess of 120 gallons, the 
proposed definitions better reflect the statutory definitions and DOE's 
statutory authority. More generally, DOE clarified that a product that 
utilizes gas, oil, or electricity to heat potable water for use outside 
the heater upon demand that does not meet the statutory definition of 
``water heater'' at 42 U.S.C. 6291(27) would be a commercial water 
heater, subject to the standards for such water heaters as set forth in 
42 U.S.C. 6313(a)(5).
    DOE received comments on the proposed removal of the temperature 
and the capacity criteria. A number of stakeholders disagreed with 
DOE's proposal to remove the 180 [deg]F water delivery temperature from 
the consumer water heater definitions at 430.2. (HTP, No. 24 at p. 2; 
AHRI, No. 26 at pp. 4-5; Rinnai, No. 31 at p. 2; Bock, No. 19 at p. 2; 
Bradford White, No. 21 at pp. 8-9; Rheem, No. 34 at pp. 10-11) AHRI 
argued that by removing these criteria, specifically the 180 [deg]F 
exclusion, from its consumer water heater definitions, DOE would be 
reversing a long-standing position that AHRI stated was determined 
valid in the July 2014 final rule. AHRI also stated that DOE did not 
provide sufficient explanation for reversing its long-standing 
position. (AHRI, No. 26 at pp. 4-5)
    Contrary to AHRI's understanding, the relocation of definitions 
from the test procedure provisions to the general definitions section 
in the July 2014 final rule was not for the purpose of validating a 
long-standing position. As noted previously, ``water heater'' is 
defined by EPCA, and remains defined in 10 CFR 430.2, without 
restriction as to water temperature delivery or storage capacity. The 
addition of these exclusions to DOE's definitions at 10 CFR 430.2 was 
not intended to limit the applicability of the definition of ``water 
heater.'' As explained in the July 2014 final rule, definitions of 
``gas-fired heat pump water heater,'' ``oil-fired instantaneous water 
heater,'' and ``electric instantaneous water heater'' were added in the 
context of the new test procedure. 79 FR 40542, 40549 (July 11, 2014). 
The notice also stated that all other definitions from the test 
procedure were being relocated. Id. The July 2014 final rule did not 
discuss restricting the statutory or regulatory definition of ``water 
heater.'' As opposed to validating a long-standing position, DOE 
recognizes that by relocating the definitions it furthered confusion 
regarding the applicability of the standards. As previously stated, 
prior to the effective date of the July 2014 final rule, any product 
meeting the definition of a ``water heater'' would have been subject to 
the statutory standards applicable to consumer water heaters, 
regardless of the water delivery temperature or storage capacity. The 
temperature and capacity restrictions were for the purpose of applying 
provisions of the test procedure, not the standard. Therefore, DOE 
considers removal of these exclusions as a correction to a recent 
change, and not as a reversal of a long-standing position. 
Additionally, as discussed in the following paragraphs, DOE has 
concluded use of such limitations would be inappropriate given, in 
part, the water heaters currently available on the market.
    AHRI further argued that when interpreting the statutory definition 
applicable to consumer water heaters, DOE must first consider the 
definition of ``consumer product.'' When determining whether a product 
falls within the definition of ``water heater'' in the context of the 
consumer product standards, AHRI argued that DOE must first consider 
whether that product is a consumer product and that the temperature and 
capacity criteria inform that consideration. AHRI pointed to prior 
consideration by DOE of factors beyond those in the EPCA definition to 
distinguish between consumer and commercial products, citing the April 
2010 final rule (75 FR 20112, 20127), in which DOE stated that pool 
heaters marketed as commercial equipment and that contain additional 
design modifications related to safety requirements for installation in 
commercial buildings would not be covered by DOE's consumer product 
standard for pool heaters. (AHRI, No. 26 at pp. 5-6) In the present 
case, AHRI essentially argued that water heaters that are designed to 
deliver water at temperatures greater than 180 [deg]F or that have a 
rated volume in excess of 120 gallons are not to any significant extent 
marketed or sold for personal use by individuals, and therefore cannot 
be consumer products. Other commenters asserted that water delivery 
temperature provides a meaningful way to distinguish between consumer 
and commercial water heaters. (Bock, No. 19 at p. 2; Bradford White, 
No. 21 at p. 9; Rinnai, No. 31 at p. 2) HTP and AHRI stated that units 
that heat water above 180 [deg]F are only used in commercial 
applications, and that water heated above 180 [deg]F in a residential 
application presents a scald hazard. (HTP, No. 24 at p. 2; AHRI, No. 26 
at p. 4) Bradford White stated that all of its commercial electric 
storage basic models would be mistakenly reclassified if DOE removed 
the 180 [deg]F exclusion from its consumer water heater definitions, 
even though according to Bradford White, these models are not 
appropriate for residential applications. (Bradford White, No. 21 at p. 
9) A.O. Smith stated that defining as consumer water heaters gas 
instantaneous water heaters with an input capacity less than or equal 
to 200,000 Btu/h and a water delivery temperature greater than 180 
[deg]F would make ratings inconsistent with other commercial water 
heaters. (A.O. Smith, No. 27 at p. 10)
    Several manufacturers also disagreed with the removal of the 
storage capacity criterion. (Bradford White, No. 21 at p. 9; A.O. 
Smith, No. 27 at p. 6; Rheem, No. 34 at p. 11) Bradford White and A.O. 
Smith stated that models with storage volume greater than 120 gallons 
require American Society of Mechanical Engineers (ASME) pressure vessel 
certification in most jurisdictions and that these models would not be 
used in residential applications. Bradford White also commented that 
the cost of ASME certification is high enough to be cost-prohibitive 
for residential applications. (Bradford White, No. 21 at p. 9)
    DOE reiterates that the relocation of definitions relevant to the 
test procedure to the general definition section at 10 CFR 430.2 was 
not intended to reflect a prior interpretation restricting the 
applicability of the standards for consumer water heaters. However, 
even if the removal of the water temperature delivery and volume 
capacity limitations were a change to a long standing practice of 
distinguishing between consumer and commercial water heaters, a recent 
survey of the

[[Page 79285]]

market leads DOE to determine that such criteria would not be 
appropriate to distinguish between water heaters that are consumer 
products and those that are commercial products. While DOE acknowledges 
that water heaters with a water delivery temperature greater than 180 
[deg]F or with a storage volume greater than 120 gallons may not be 
commonly used in residential applications, the question is whether a 
water heater is of the type distributed in commerce to any significant 
extent for personal use by an individual. (42 U.S.C. 6291(1)) 
Consideration of whether an article is of a type distributed in 
commerce to any significant extent for personal use by an individual is 
made without regard to whether a specific article is in in fact 
distributed in such a manner. Id.
    In surveying the market, DOE has identified several water heaters 
that demonstrate that a reliance on a 180 [deg]F threshold would be 
inappropriate for distinguishing between consumer and commercial water 
heaters. Rheem markets a water heater under its commercial line that 
has input ratings below the 12 kW threshold specified in the statutory 
definition for consumer water heaters and has thermostat controls that 
provide maximum water temperatures greater than 180 [deg]F. (Docket No. 
EERE-2014-BT-TP-0008-0041) This water heater's installation 
instructions reference installation in the ``home,'' indicating that 
the model is distributed for consumer use. (Docket No. EERE-2014-BT-TP-
0008-0040, pp. 15, 21) A water heater offered by A.O. Smith has two 4.5 
kW heating elements arranged in a configuration typical for consumer 
water heaters and provides an input capacity below the statutory 12 kW 
threshold, but has a thermostat adjustable up to 181 [deg]F, one degree 
above the 180 [deg]F threshold in the regulatory definition of 
``electric storage water heater.'' (Docket No. EERE-2014-BT-TP-0008-
0038) The manual for the A.O. Smith product references installation in 
the home, again suggesting that the product is distributed, at least to 
an extent, for residential use. (Docket No. EERE-2014-BT-TP-0008-0037, 
pp. 8-9)
    With regard to the 180 [deg]F criterion, DOE's understanding is 
that exceeding the temperature threshold for a water heater can be 
achieved through replacement of a single part, the thermostat, which 
DOE believes can be very easily and inexpensively changed to allow for 
heating water to greater than 180 [deg]F. As noted by A.O. Smith in its 
comment, the 180 [deg]F operating limit is not necessarily a 
satisfactory criterion for separating consumer and commercial water 
heaters, because a thermostat designed to deliver water temperatures in 
excess of 180 [deg]F can be installed at no additional cost on products 
that are consumer water heaters in all other respects. (A.O. Smith, No. 
27 at pp. 6-7) A.O. Smith suggested that removing the 180 [deg]F 
criterion for electric storage water heaters could dissuade 
manufacturers from trying to avoid DOE's standard for large residential 
electric storage water heaters.\13\ (A.O. Smith, No. 27 at pp. 6-7) 
Additionally, Rheem suggested that the 180 [deg]F criterion for 
distinguishing between residential-duty commercial water heaters and 
other commercial water heaters allows manufacturers to move units in 
and out of the residential-duty commercial water heater classes using a 
thermostat. (Docket No. EERE-2014-BT-STD-0042-0020 at p. 18) DOE 
believes that the same allowance to move between classes would apply to 
a 180 [deg]F criterion that distinguished between consumer water 
heaters and commercial water heaters. Bradford White stated in its 
comments that the only feature to distinguish some if its models as 
commercial is the temperature requirement. (Bradford White, No. 21 at 
p. 9) The ease at which water temperature in excess of 180 [deg]F can 
be achieved by a water heater that is in all regards a consumer water 
heater demonstrate that the 180 [deg]F threshold would circumvent the 
statutory definition of a consumer water heater. DOE also notes that 
the concern raised by commenters regarding scalding is applicable to 
lower water temperatures as well. Manufacturer warnings regarding 
scalding identify the danger at temperatures as low as 125 [deg]F, and 
with an exposure time of 1 second at 155 [deg]F. (Docket No. EERE-2014-
BT-TP-0008-0037) The range of the temperatures at which warnings are 
issued indicate that 180 [deg]F would not be an adequate threshold to 
delineate the risk of scalding, further demonstrating that a threshold 
of 180 [deg]F does not provide a meaningful distinction between 
consumer and commercial water heaters.
---------------------------------------------------------------------------

    \13\ A.O. Smith did support maintaining the 180 [deg]F criterion 
for other water heaters, but did not provide an explanation for why 
its statements provided in regards to electric storage water heaters 
would not apply to other water heaters. (A.O. Smith, No. 27 at p. 7)
---------------------------------------------------------------------------

    GE supported DOE's proposal to remove the 180 [deg]F exclusion from 
DOE's consumer water heater definitions, suggesting that the change 
would end the shift in shipments from residential electric storage 
water heaters to commercial electric storage water heaters. GE also 
stated that a rulemaking should not be necessary for these changes, and 
that DOE should make these changes in a guidance document. If these 
changes are made in a rulemaking, GE suggested that the effective date 
should be immediate. (GE, No. 25 at pp. 1-2)
    With regard to the 120 gallon threshold, DOE has determined that in 
the interest of avoiding future confusion, it is not adding this 
criterion to the definition of consumer water heater. DOE has 
determined that the simplest way to maintain the distinction as 
established by Congress between consumer and commercial water heaters 
is to rely solely on the definition set forth in EPCA.
    As explained previously, the 180 [deg]F and 120 gallon rated volume 
criteria were for the purpose of defining terms in the context of the 
test procedures for consumer water heaters. Such distinctions are 
unnecessary under DOE's current test procedures for consumer water 
heaters, as adopted in the July 2014 final rule, which also applies to 
residential-duty commercial water heaters. To correct the application 
of such thresholds to the definitions pertaining to consumer water 
heaters, DOE is removing them from the definitions. Additionally, based 
on a survey of the market and based on several of the comments 
received, DOE has determined that these criteria would be inappropriate 
for distinguishing between consumer and commercial water heaters. EPCA 
delineates between consumer and commercial water heaters in the 
statutory definition through specified rated inputs. As evidenced by 
the discussion of the products surveyed, the addition of further 
criteria does not provide a meaningful distinction between consumer and 
commercial water heaters. To add a temperature or volume criterion 
would potentially exclude some consumer water heaters from the 
regulatory definition of a consumer water heater, but not the statutory 
definition, and such a result would be an inappropriate restriction on 
the definition of consumer water heater provided in EPCA.
    DOE has previously considered adding criteria to its codified 
definitions beyond the statutory criteria to distinguish between 
consumer and commercial products. In the case of pool heaters, a 
consumer product, commenters and DOE recognized that there were 
performance and design characteristics that further informed a 
determination of whether a pool heater was a consumer product or a 
commercial product. 75 FR 20112, 20127 (April 16, 2010). For pool 
heaters, DOE declined to add those criteria to

[[Page 79286]]

the definition of pool heater, finding that amendments to the statutory 
definition were unnecessary and that marketing and design differences 
related to safety requirements for installation in commercial buildings 
sufficiently informed the distinction between consumer and commercial 
products. Id. That is, the definition established by EPCA did not 
require further clarification.
    However, the consideration for pool heaters is not wholly analogous 
to the present case. Unlike the present case and the consideration of a 
temperature threshold, the additional criteria discussed for pool 
heaters would not have limited the application of the defined term 
``pool heater'' established in statute (i.e., the criteria discussed 
for pool heaters would not have excluded pool heaters that are 
otherwise consumer products from standards). Here, the addition of a 
temperature threshold would exclude water heaters from consideration as 
consumer water heaters that under the statutory definition are consumer 
water heaters, and are of the type distributed in commerce for personal 
use by individuals.
    EPCA does not exclude water heaters based on water temperature 
delivery or volume in its definition for consumer ``water heater.'' 
Rather, the definition in EPCA relies on input criteria to define which 
water heaters fall under the consumer ``water heater'' definition, and 
DOE believes that in order to maintain consistency with EPCA, the 
inclusion of these criteria is not appropriate.
    Several commenters asserted that the removal of the exclusion from 
the consumer water heater definitions of models with a water delivery 
temperature of 180 [deg]F or higher is inconsistent with the definition 
of a ``residential-duty commercial water heater'' that DOE established 
in the July 2014 final rule for test procedures for consumer water 
heaters and certain commercial water heaters. 79 FR 40542, 40586 (July 
11, 2014). Specifically, commenters noted that in that rule, DOE 
included water delivery temperature of 180 [deg]F or higher as an 
indicator of non-residential application for commercial water heaters, 
and stated that such units would generally only be used in commercial 
settings. (AHRI, No. 26 at pp. 4-5; Rinnai, No. 31 at p. 2; Bradford 
White, No. 21 at pp. 8-9) Rheem also suggested that removing the 180 
[deg]F and 120 gallon criteria from the consumer water heater 
definitions while maintaining water delivery temperature of greater 
than 180 [deg]F and storage volume greater than 120 gallons as 
distinguishing criteria for commercial water heaters not used in 
residential applications (i.e., not residential-duty commercial water 
heaters) would lead to confusion in the market place. (Rheem, No. 34 at 
p. 10)
    In the July 2014 final rule, DOE established a new class of 
commercial water heaters, ``residential-duty commercial water heater.'' 
79 FR 40542, 40586 (July 11, 2014). EPCA, as amended by AEMTCA, allowed 
DOE to exclude from a uniform energy descriptor water heaters that do 
not have residential applications and that can be clearly described. 
(42 U.S.C. 6295(e)(5)(F)) Under this authority, DOE established several 
criteria to separate commercial water heaters that have residential 
applications (i.e., residential-duty commercial water heaters) from 
commercial water heaters generally. Id. at 40586. When determining how 
to distinguish a residential-duty commercial water heater from other 
commercial water heaters, DOE relied on an outlet water temperature of 
180 [deg]F or lower as one of several dividing criteria. 79 FR 40542, 
40546 (July 11, 2014). DOE noted that although residential-duty 
commercial water heaters could have residential applications, the 
``residential-duty commercial water heater'' definition represents a 
type of water heater that, to a significant extent, is distributed in 
commerce for industrial or commercial use. Id. In its explanation for 
this criterion, DOE stated that a 180 [deg]F water delivery temperature 
is a valuable distinguishing feature between commercial water heaters 
intended for residential use and those that are not. However, water 
delivery temperature serves in conjunction with other criteria to 
distinguish residential-duty commercial water heaters from other 
commercial water heaters (i.e., rated storage volume, rated input, and 
for models requiring electricity, and use of a single-phase external 
power supply are also considered). See 10 CFR 431.102.
    EPCA provides a criterion for distinguishing between water heaters 
that are consumer products and water heaters that are commercial and 
industrial equipment: The rated input. (42 U.S.C. 691(27)) Although 
water delivery temperature and rated storage capacity are useful as 
part of the analysis to differentiate between commercial water heater 
applications, as explained above, water delivery temperature and rated 
storage capacity are inappropriate to distinguish between consumer 
water heaters and commercial water heaters.
    A. O. Smith and Raypak both argued that it was inappropriate to 
address the definitions of consumer water heaters in this rulemaking 
since this rulemaking primarily addresses test procedures for water 
heaters as commercial products. (A. O. Smith, No. 27 at p. 7; Raypak, 
No. 28 at p. 7) As noted by Raypak, the water heaters excluded under 
the consumer water heater definition in EPCA and 10 CFR 430.2 are 
subject to the commercial water heater standards in 10 CFR part 431. By 
removing the outlet water temperature and capacity criteria, DOE is 
clarifying the distinction between consumer water heaters and 
commercial water heaters as prescribed by EPCA. DOE believes removing 
the water temperature and volume references will simplify its 
regulations. Those water heaters with a rated input in excess of the 
applicable maximum specified in EPCA (42 U.S.C. 6311(12)) are 
commercial water heaters and will be regulated under EPCA as industrial 
equipment under 42 U.S.C. 6311(1), meaning that those commercial water 
heaters cannot be a covered consumer product under 42 U.S.C. 6291(1).
    Additionally, contrary to Bradford White's suggestion, not all 
electric storage water heater basic models will need to be reclassified 
under this final rule. (Bradford White, No. 27 at p. 9) Only electric 
storage models with an input rating less than or equal to 12 kW must be 
classified as consumer water heaters. All electric storage models with 
an input rating greater than 12 kW are classified as commercial water 
heaters.
    For the reasons previously discussed, DOE is removing the 
180[emsp14][deg]F water delivery temperature and 120 gallon storage 
volume exclusions from its consumer water heater definitions, as 
proposed in the May 2016 NOPR. Because DOE is modifying the 
regulations, such changes cannot be addressed through a guidance 
document. The effective date of these definition changes is 30 days 
after publication of this final rule in the Federal Register.
    In the May 2016 NOPR, DOE also proposed to remove the terms 
``electric heat pump water heater'' and ``Gas-fired heat pump water 
heater'' from its definitions at 10 CFR 430.2. 81 FR 28588, 28606 (May 
9, 2016). DOE reasoned that these terms were unnecessary because they 
are not used in the energy conservation standards for consumer water 
heaters at 10 CFR 430.32(d), nor are they used in the Uniform Test 
Method for Measuring the Energy Consumption of Water Heaters at 
appendix E to subpart B of part 430.
    In response to this proposal, Rheem disagreed with the removal of 
the terms ``electric heat pump water heater'' and ``gas-fired heat pump 
water heater'' from

[[Page 79287]]

DOE's definitions at 10 CFR 430.2. Rheem stated that heat pump water 
heaters have different defining factors than other kinds of consumer 
water heaters, and that the threshold input rate only represents the 
power being supplied from the non-heat pump technology involved with 
heating the stored water. (Rheem, No. 34 at pp. 11-12)
    As proposed in the May 2016 NOPR, DOE is removing the definitions 
for ``electric heat pump water heater'' and ``gas-fired heat pump water 
heater'' from its regulations. DOE acknowledges that heat pump water 
heaters can have different defining factors than other consumer water 
heaters, but DOE is removing these definitions because they are not 
used in DOE's test procedures or energy conservations standards for 
consumer waters. Therefore, removing these definitions will have no 
effect on the implementation of DOE's regulations.
    As discussed in the previous paragraphs, DOE is revising the 
definitions for ``electric instantaneous water heater,'' ``electric 
storage water heater,'' ``gas-fired instantaneous water heater,'' 
``gas-fired storage water heater,'' ``oil-fired instantaneous water 
heater,'' and ``oil-fired storage water heater'' in its regulations of 
consumer water heaters at 10 CFR 430.2, as set out in the regulatory 
text at the end of this document.
2. Commercial Water Heating Equipment
    DOE currently includes several definitions in its regulations for 
CWH equipment at 10 CFR 431.102 that include the terms ``rated input'' 
or ``input rating.'' These definitions include ``hot water supply 
boiler,'' ``instantaneous water heater,'' ``residential-duty commercial 
water heater,'' and ``storage water heater.'' In the May 2016 NOPR, DOE 
proposed a new definition for ``fuel input rate,'' a value to be 
certified for all gas-fired and oil-fired CWH equipment. 81 FR 28588, 
28637 (May 9, 2016). Therefore, DOE also proposed replacing the terms 
``rated input'' and ``input rating'' with the term ``fuel input rate'' 
for gas-fired and oil-fired CWH equipment in the definitions for CWH 
equipment at 10 CFR 431.102. 81 FR 28588, 28606 (May 9, 2016).
    As discussed in section III.L.1 of this final rule, based on 
feedback from stakeholders regarding the rated input determined from 
safety certification, DOE is not adopting its proposed requirements 
regarding certification of fuel input rate. Therefore, in this final 
rule, DOE is not modifying its definitions for CWH equipment at 10 CFR 
431.102 as proposed in the May 2016 NOPR. Instead, DOE is adopting the 
term ``rated input'' in its definitions to refer to the input capacity 
certified to DOE by the manufacturer and included on the equipment 
nameplate. In contrast, DOE is adopting the term ``fuel input rate'' in 
its regulations only to refer to the capacity of a unit determined in a 
particular test.
    DOE's current definitions for ``storage water heater'' and 
``instantaneous water heater'' in its regulations for CWH equipment 
codified at 10 CFR 431.102 do not include any criteria that exclude 
units that meet DOE's current definitions for consumer water heaters, 
as codified at 10 CFR 430.2. In the May 2016 NOPR, DOE proposed to 
clarify these definitions for commercial water heaters by adding the 
input capacity criteria that distinguish between consumer and 
commercial water heaters for each energy source, as specified in EPCA's 
definition for consumer water heater (42 U.S.C. 6291(27)). 81 FR 28588, 
28637 (May 9, 2016). These changes are consistent with DOE's changes to 
its definitions for consumer water heaters, as discussed in section 
III.G.1.
    In response to the May 2016 NOPR, Bradford White agreed with DOE's 
proposal to add the input criteria separating consumer and commercial 
water heaters to the definitions for commercial water heaters. 
(Bradford White, No. 21 at pp. 9, 12) Raypak commented that DOE should 
establish an upper limit of 5 million Btu/h in its definitions for 
commercial water heating equipment because of laboratory testing issues 
for larger equipment. Raypak also noted that while hot water supply 
boilers are restricted to under 12.5 million Btu/h, no similar 
restriction exists for commercial water heaters. (Raypak, No. 28 at p. 
7)
    As proposed in the May 2016 NOPR and for the reasons previously 
stated, in this final rule, DOE is clarifying its definitions for 
commercial water heaters by adding the input capacity criteria that 
distinguish between consumer and commercial water heaters for each 
energy source, as specified in EPCA's definition of consumer water 
heater. (42 U.S.C. 6291(27))
    In response to Raypak's suggestion that DOE should establish an 
upper input capacity limit in its CWH equipment definitions, DOE notes 
that the statutory definitions of ``storage water heater'' and 
``instantaneous water heater'' at 42 U.S.C. 6311(12)(A) do not set an 
upper-end input capacity limit in terms of coverage of commercial water 
heaters, so any large-scale models are already covered under DOE's 
existing energy conservation standards. Even so, DOE was unable to 
identify any models of CWH equipment currently on the market with an 
input capacity greater than 5 million Btu/h. In fact, Raypak noted that 
the largest input capacity of any CWH equipment that it manufactures is 
only 4 million Btu/h. (Raypak, No. 28 at p. 6) DOE would only consider 
modifying its regulations for large CWH equipment if there were such 
units on the market and if manufacturers demonstrated that DOE's 
existing test procedures could not be used for these units. If a 
manufacturer does produce a CWH equipment model with an input capacity 
greater than 5 million Btu/h that cannot be tested using DOE's test 
procedure, then the manufacturer should notify DOE and request a waiver 
from DOE's test procedures using the procedure at 10 CFR 431.401. If a 
waiver were granted, DOE would update its test procedure in the next 
test procedure rulemaking for CWH equipment.
    DOE currently includes a definition for ``instantaneous water 
heater'' in its regulations for CWH equipment at 10 CFR 431.102. An 
instantaneous water heater is a water heater that has an input rating 
not less than 4,000 Btu/h per gallon of stored water, and that is 
industrial equipment, including products meeting this description that 
are designed to heat water to temperatures of 180[emsp14][deg]F or 
higher.
    DOE believes that the last clause of the definition for 
``instantaneous water heater,'' which includes units capable of heating 
water to temperature at or above 180[emsp14][deg]F, does not serve a 
purpose in the definition. Without this clause, it would be assumed 
that units with this capability would be included in the definition 
because there is no restriction indicating otherwise. Therefore, to 
simplify the definition, DOE is removing this clause from the 
definition for ``instantaneous water heater.'' Additionally, with DOE's 
addition of input criteria that distinguish between consumer and 
commercial water heaters previously discussed in this section, DOE 
believes that the clause ``that is industrial equipment'' does not 
serve to further clarify the scope of units covered by this definition. 
Therefore, in the May 2016 NOPR, DOE proposed to remove this clause 
from its definitions for ``instantaneous water heater'' and ``storage 
water heater.'' 81 FR 28588, 28606 (May 9, 2016). In response to the 
May 2016 NOPR, Bradford White agreed with removing the phrase ``that is 
industrial equipment.'' (Bradford White, No. 21 at p. 9) Bradley 
Corporation requested clarification from DOE on the removal of the 
phrase ``that is industrial

[[Page 79288]]

equipment'' from the definition of instantaneous water heaters, and 
whether this phrase is actually in reference to the statutory 
definition for ``industrial equipment.'' (Bradley, NOPR Public Meeting 
Transcript, No. 20 at p. 23)
    The term ``industrial equipment'' used in the definitions for 
``instantaneous water heater'' and ``storage water heater'' at 10 CFR 
431.102 does refer to the statutory definition for ``industrial 
equipment.'' (42 U.S.C. 6311(2)(A)) The phrase ``that is industrial 
equipment'' was included in DOE's codified definitions for 
``instantaneous water heater'' and ``storage water heater'' to clarify 
that water heaters that are covered by EPCA's definition of ``water 
heater'' under ``consumer products'' (see U.S.C. 6291(27)) are not 
covered by DOE's definitions for ``instantaneous water heater'' and 
``storage water heater'' in 10 CFR part 431. DOE believes that the 
phrase ``that is industrial equipment'' is no longer needed in DOE's 
definitions for ``instantaneous water heater'' and ``storage water 
heater'' to clarify that products regulated as consumer products are 
not covered under these definitions, because DOE is modifying these 
definitions to include the specific input capacity criteria that 
separate consumer water heaters and commercial water heaters, as 
previously discussed in this section. The statutory definition for 
``industrial equipment'' also includes that equipment be of a type that 
is distributed, to any significant extent, in commerce for commercial 
or industrial applications. (42 U.S.C. 6311(2)(A)(ii)) However, EPCA 
also defines ``covered equipment'' to include any of several types of 
industrial equipment, including storage water heaters, instantaneous 
water heaters, and unfired hot water storage tanks. (42 U.S.C. 6311(1)) 
Therefore, covered commercial water heating equipment is, by statutory 
definition, industrial equipment. Consequently, DOE believes that the 
phrase ``that is industrial equipment'' is not needed in DOE's codified 
definitions for ``instantaneous water heater'' and ``storage water 
heater.'' Therefore, in this final rule, DOE is removing this clause 
from its definitions for ``instantaneous water heater'' and ``storage 
water heater.''
    In its regulations for CWH equipment at 10 CFR 431.102, DOE 
currently includes a definition for ``packaged boiler'' that is 
identical to that included for commercial packaged boilers at 10 CFR 
431.82. DOE includes this definition for ``packaged boiler'' at 10 CFR 
431.102 because the regulations for CWH equipment also include a 
definition for ``hot water supply boiler,'' and this definition 
specifies that a hot water supply boiler is a kind of packaged boiler. 
To simplify its regulations and reduce repetition, in the May 2016 
NOPR, DOE proposed to remove the definition for ``packaged boiler'' 
from its regulations for CWH equipment at 10 CFR 431.102, to be 
replaced with a reference to the definition for ``packaged boiler'' 
included at 10 CFR 431.82. 81 FR 28588, 28606 (May 9, 2016). In 
response to the May 2016 NOPR, Bradford White agreed with removing the 
definition of ``packaged boiler,'' as long as this change is consistent 
with the commercial packaged boiler rulemakings. (Bradford White, No. 
21 at p. 9) DOE notes that replacement of a duplicated definition with 
a reference to the regulations for commercial packaged boilers 
inherently aligns DOE's regulations for commercial packaged boilers and 
CWH equipment, such that there is no potential for differences between 
two versions of the ``packaged boiler'' definition. Therefore, DOE is 
removing the definition of ``packaged boiler'' from its regulations for 
CWH equipment at 10 CFR 431.102. Correspondingly, in its definition of 
``hot water supply boiler'' at 10 CFR 431.102, DOE is replacing the 
term ``packaged boiler'' with the term ``packaged boiler (as defined in 
Sec.  431.82).''
    In section III.H of this final rule, DOE establishes a separate 
test procedure for water heaters and hot water supply boilers that 
require flow of water to activate the burner or heating element, and 
establishes a definition for ``flow-activated water heater,'' along 
with separate standby loss test provisions for flow-activated water 
heaters as set out in the regulatory text at the end of this document.
    In section III.J of this final rule, DOE establishes a definition 
for ``commercial heat pump water heater,'' as well as a test procedure 
for commercial heat pump water heaters as set out in the regulatory 
text at the end of this document.
3. Residential-Duty Commercial Water Heaters
    As required by AEMTCA, DOE established a uniform efficiency 
descriptor and accompanying test method for consumer water heaters and 
certain commercial water heaters in the July 2014 final rule. 79 FR 
40542 (July 11, 2014). Specifically, AEMTCA required that the uniform 
efficiency descriptor and test method apply to all covered water 
heaters, including both consumer and commercial water heaters, except 
for certain commercial water heaters that do not have a residential 
use, and can be clearly described and are effectively rated using the 
thermal efficiency and standby loss descriptors. (42 U.S.C. 
6295(e)(5)(F)) In the July 2014 final rule, DOE established input and 
volume criteria to distinguish commercial water heaters that do not 
have residential applications, based on comments from stakeholders. 79 
FR 40542, 40586 (July 11, 2014). However, for four classes of 
residential-duty commercial water heaters--electric storage water 
heaters, heat pump water heaters, gas-fired instantaneous water 
heaters, and oil-fired instantaneous water heaters--the input criteria 
established to separate residential-duty commercial water heaters from 
commercial water heaters are identical to those codified at 10 CFR 
430.2, which separate consumer water heaters from commercial water 
heaters. The criteria for these classes are shown in Table III-1. 
Because these input criteria are identical, by definition, no models 
can be classified under these four residential-duty equipment classes. 
Therefore, to eliminate potential confusion, in the May 2016 NOPR, DOE 
proposed to remove these classes from the definition of ``residential-
duty commercial water heater'' codified at 10 CFR 431.102. 81 FR 28588, 
28607 (May 9, 2016).

    Table III--1 Indicator of Non-Residential Application for Certain
                        Classes of CWH Equipment
------------------------------------------------------------------------
                                           Indicator of non-residential
           Water heater class                      application
------------------------------------------------------------------------
Electric storage.......................  Rated input >12 kW; Rated
                                          storage volume >120 gallons.
Heat pump with storage.................  Rated input >12 kW; Rated
                                          current >24A at a rated
                                          voltage of not greater than
                                          250 V; Rated storage volume
                                          >120 gallons.
Gas-fired instantaneous................  Rated input >200 kBtu/h; Rated
                                          storage volume >2 gallons.
Oil-fired instantaneous................  Rated input >210 kBtu/h; Rated
                                          storage volume >2 gallons.
------------------------------------------------------------------------


[[Page 79289]]

    In response to the May 2016 NOPR, several commenters agreed with 
DOE's proposal to revise the definition of ``residential-duty 
commercial water heater.'' (Bradford White, No. 21 at p. 9; CA IOUs, 
No. 23 at p. 2; AHRI, No. 26 at p. 13; A.O. Smith, No. 27 at p. 10) 
Rheem, however, disagreed, asserting that there should be a 
residential-duty commercial class corresponding to each equipment class 
of commercial water heaters. Rheem argued that only having residential-
duty commercial classes for certain kinds of water heaters is 
arbitrary, and that all classes of commercial water heaters have units 
that are installed in residential applications. Further, Rheem stated 
that it would be extremely costly and burdensome to implement a heat 
pump water heater standard for commercial water heaters, and that a 
class for residential-duty commercial electric storage water heaters is 
necessary to maintain the ability to install electric storage water 
heaters using electric resistance heating elements in certain 
commercial applications. Rheem suggested that the class of residential-
duty commercial electric storage water heaters should include units 
with an input capacity less than or equal to 13 kW and a storage volume 
no greater than 120 gallons. (Rheem, No. 34 at pp. 13-14)
    In response to Rheem, DOE notes that it did not propose to change 
any of the criteria for classifying residential-duty commercial water 
heaters in the May 2016 NOPR, only to remove classes for which no units 
could be classified given the existing criteria. Further, the existing 
capacity criteria for defining non-residential application for 
commercial water heaters were established in the July 2014 final rule 
based on feedback from stakeholders, including Rheem. 79 FR 40542, 
40545-40549 (July 11, 2014). Having classes of residential-duty 
commercial water heaters for only certain classes of commercial water 
heaters is not inherently arbitrary, as suggested by Rheem. Rather, it 
reflects that for certain equipment classes of commercial water heaters 
(as defined by the statutory criteria separating consumer water heaters 
and commercial water heaters), commenters in the prior rulemaking 
generally agreed that there is no capacity range in which units are 
distributed to residential applications to a significant extent.
    On May 31, 2016, DOE published a NOPR for amended energy 
conservation standards for certain classes of CWH equipment. 81 FR 
34440. For commercial electric storage water heaters, DOE only proposed 
to amend the standby loss standard in that NOPR. Therefore, DOE does 
not have any current or proposed energy conservation standards that 
would require commercial electric storage water heaters to use heat 
pump technology instead of electric resistance heating elements. 
Consequently, DOE disagrees with Rheem's statement that a class of 
residential-duty commercial electric storage water heaters is warranted 
for the purpose of excluding a certain group of commercial water 
heaters from coverage under a standard that requires heat pump 
technology. Additionally, DOE notes that Rheem's suggested input 
capacity limit for residential-duty electric storage water heaters of 
13 kW differs only slightly from the statutory input capacity criterion 
separating consumer water heaters from commercial water heaters--12 kW. 
DOE was only able to identify one electric storage water heater on the 
market with an input capacity both greater than 12 kW and less than or 
equal to 13 kW. (Docket No. EERE-2014-BT-TP-0008-0039) Because this 
unit, sold by Rheem, is marketed as a commercial water heater and 
included in the same model line as units with input capacities of 18 kW 
and 24 kW, DOE believes that this 12.4 kW unit is appropriately 
classified as a commercial electric storage water heater under the 
statute and DOE is not at liberty to modify those definitions. Since 
all three of these water heaters are marketed by the manufacturer in 
the product literature as commercial electric storage water heaters, 
DOE does not see the basis for differential treatment as Rheem is 
suggesting.
    Accordingly, in this final rule, as proposed in the May 2016 NOPR, 
DOE is removing four classes of residential-duty commercial water 
heaters--electric storage water heaters, heat pump water heaters, gas-
fired instantaneous water heaters, and oil-fired instantaneous water 
heaters--from the definition of ``residential-duty commercial water 
heater'' codified at 10 CFR 431.102.
4. Storage-Type Instantaneous Water Heaters
    The definitions of ``instantaneous water heater'' and ``hot water 
supply boiler'' set forth in 10 CFR 431.102 include CWH equipment with 
an input rating of at least 4,000 Btu/h per gallon of stored water. 
These definitions, therefore, include both instantaneous water heaters 
and hot water supply boilers without integral storage tanks, as well as 
instantaneous water heaters with integral storage tanks (but with at 
least 4,000 Btu/h of input per gallon of stored water). DOE believes 
these two groups of equipment--water heaters with and without integral 
storage tanks--are fundamentally different in their construction and 
application, and have different energy losses that need to be accounted 
for during efficiency testing. Consequently, DOE believes that 
instantaneous water heaters with an integral storage tank (``storage-
type instantaneous water heaters'') should be tested in a manner 
similar to commercial storage water heaters. Therefore, in the May 2016 
NOPR, DOE proposed to define ``storage-type instantaneous water 
heater,'' and to require that storage-type instantaneous water heaters 
be tested using the same test procedure as used for commercial storage 
water heaters. 81 FR 28588, 28607 (May 9, 2016). Specifically, DOE 
proposed to define ``storage-type instantaneous water heater'' as an 
instantaneous water heater that includes a storage tank with a 
submerged heat exchanger(s) or heating element(s).
    In response to the May 2016 NOPR, NEEA and Joint Advocates agreed 
that storage-type instantaneous water heaters should be tested in a 
similar manner to storage water heaters. (NEEA, No. 30 at p. 1; Joint 
Advocates, No. 32 at p. 2) NEEA also agreed with DOE's proposed 
definition for ``storage-type instantaneous water heater.'' (NEEA, No. 
30 at p. 1) Bradford White and A.O. Smith stated that a definition and 
equipment class for storage-type instantaneous water heaters are 
unnecessary. (Bradford White, No. 21 at p. 9; A.O. Smith, NOPR Public 
Meeting Transcript, No. 20 at p. 17) A.O. Smith also stated that 
storage-type instantaneous water heaters have always been tested like 
storage water heaters. (A. O. Smith, NOPR Public Meeting Transcript, 
No. 20 at p. 17) Several commenters stated that the definition of 
``storage-type instantaneous water heater'' should not include a 
submerged heat exchanger or heating element because there are models on 
the market without a submerged heat exchanger that should be included 
in this class. (Bradford White, No. 21 at p. 12; AHRI, No. 26 at p. 13; 
A.O. Smith, No. 27 at p. 11; Raypak, No. 28 at p. 7; Rheem, No. 34 at 
p. 14)
    While DOE's existing test procedures do not distinguish between 
storage water heaters and instantaneous water heaters, in this final 
rule, DOE is separating its test procedures for storage water heaters 
and instantaneous water heaters. Therefore, DOE disagrees with Bradford 
White and A.O. Smith, and believes a clarification of which test 
procedure to use for testing storage-type instantaneous water heaters 
and a definition for classifying storage-type instantaneous water 
heaters are

[[Page 79290]]

warranted so as to eliminate any ambiguity.
    After further assessment of tank-type water heaters currently on 
the market, DOE agrees with commenters that its proposed definition of 
``storage-type instantaneous water heater'' excludes certain kinds of 
water heaters that should be included in this class. Specifically, the 
proposed requirement that a storage-type instantaneous water heater 
contain a submerged heat exchanger or heating element excludes units 
such as those with a water-tube heat exchanger located outside the 
tank, or models comprising a storage tank and a tankless water heater 
mounted to the side of the tank. Therefore, DOE is not including this 
specification for a submerged heat exchanger or heating element in the 
definition for ``storage-type instantaneous water heater'' established 
in this final rule.
    In the absence of a specification for a submerged heat exchanger or 
heating element, DOE believes that the definition of ``storage-type 
instantaneous water heater'' needs an alternative specification to 
distinguish between tank-type water heaters and instantaneous-type 
water heaters that include a small holding tank (e.g., 1-2 gallons). 
Both of these categories of water heaters would meet a definition that 
specifies only that a storage-type instantaneous water heater includes 
a tank. DOE believes that a storage volume of ten gallons effectively 
separates these two categories of water heaters, and this criterion 
aligns with DOE's current energy conservation standards, which include 
a standby loss standard for instantaneous water heaters with a storage 
volume greater than or equal to ten gallons.
    Accordingly, in this final rule, DOE is adopting test procedures in 
the regulatory text at the end of this document that require testing of 
storage water heaters and storage-type instantaneous water heaters 
using the same procedures. DOE is also defining ``storage-type 
instantaneous water heater'' as an instantaneous water heater including 
a storage tank with a storage volume of ten gallons or greater.

H. Standby Loss Test for Instantaneous Water Heaters and Hot Water 
Supply Boilers

    The current Federal standby loss test method for CWH equipment 
incorporates by reference Exhibit G.2 of ANSI Z21.10.3-2011 for 
determining the standby loss of instantaneous water heaters and hot 
water supply boilers with greater than 10 gallons of storage volume. 10 
CFR 431.110. This test method assumes that the water heater would 
automatically initiate the next firing cycle when the internal water 
temperature (measured using the internal tank thermostat) falls below 
its allowable minimum value. This control system operation applies to 
some CWH equipment, but is not applicable to certain instantaneous 
water heaters and hot water supply boilers that require continuous 
water flow through the heat exchanger in order to activate the next 
firing cycle. Accordingly, in the May 2016 NOPR, DOE proposed a 
separate test method for ``flow-activated instantaneous water 
heaters,'' which DOE proposed to define as an instantaneous water 
heater or hot water supply boiler that does not activate the burner or 
heating element if no heated water is drawn from the unit. 81 FR 28588, 
28607-28613 (May 9, 2016). DOE's proposed test method and the method 
adopted in this final rule are discussed in further detail in section 
III.H.3.
    In addition to the proposed test procedure for flow-activated 
instantaneous water heaters, DOE also proposed in the May 2016 NOPR to 
update the standby loss test procedure for instantaneous water heaters 
and hot water supply boilers (other than flow-activated instantaneous 
water heaters and storage-type instantaneous water heaters). The 
existing Federal standby loss test procedure requires the measurement 
of the mean tank temperature to calculate the standby loss. 
Instantaneous water heaters and hot water supply boilers (other than 
storage-type instantaneous water heaters) are not equipped with an 
integral storage tank, and instead, most of the stored water is within 
the heat exchanger. Therefore, obtaining a measurement for the mean 
tank temperature would not be possible for such units, because heat 
exchanger geometry generally prevents an accurate internal stored water 
measurement that would be comparable to a mean tank temperature in 
tank-type models. DOE notes that the mean tank temperature for storage 
and storage-type instantaneous water heaters represents the hot water 
stored in the heat exchanger and that is subject to heat loss during 
the standby loss test. However, unlike storage water heaters and 
storage-type instantaneous water heaters, instantaneous water heaters 
and hot water supply boilers generally have water-tube heat exchangers 
\14\ and do not store water at a uniform temperature inside the heat 
exchanger. Consequently, DOE proposed in the May 2016 NOPR to use the 
outlet water temperature as an approximation for the stored water 
temperature (instead of the mean tank temperature as required by Annex 
E.2 of ANSI Z21.10.3-2015, the latest industry test method). 81 FR 
28588, 28615-28617 (May 9, 2016). In the May 2016 NOPR, DOE also 
proposed a storage volume determination test for all instantaneous 
water heaters and hot water supply boilers (including flow-activated 
instantaneous water heaters), similar to the method specified in 
section 5.27 of ANSI Z21.10.3-2015. 81 FR 28588, 28612 (May 9, 2016).
---------------------------------------------------------------------------

    \14\ By water-tube heat exchangers, DOE refers to a heat 
exchanger where water flows inside heat exchanger tubes and is 
heated by a source of energy external to the tubes.
---------------------------------------------------------------------------

    The following sections discuss the comments received in response to 
each of these proposals.
1. Definition of Flow-Activated Instantaneous Water Heater
    As noted previously, in the May 2016 NOPR, DOE proposed to define 
``flow-activated instantaneous water heater'' as an instantaneous water 
heater or hot water supply boiler that does not activate the burner or 
heating element if no heated water is drawn from the unit. 81 FR 28588, 
28608 (May 9, 2016).
    In response, NEEA and Bradley supported DOE's proposed definition 
for ``flow-activated instantaneous water heater.'' NEEA stated that the 
definition would allow such equipment to have a better delineation of 
efficiency. Bradley agreed that the proposed definition captures the 
types of water heaters that exist on the market. (NEEA, No. 30 at p. 1; 
Bradley, No. 33 at p. 1) A.O. Smith suggested that the proposed 
definition for flow-activated instantaneous water heater is not 
necessary and may cause confusion. (A.O. Smith, No. 27 at p. 11) Rheem 
suggested amending the definition of flow-activated instantaneous water 
heaters such that it does not include double-negative wording, and 
recommended defining ``flow-activated instantaneous water heater'' as a 
unit that activate the burner or heating element when water is drawn 
from the unit. Rheem also stated that, provided that the proposed 
definition is simplified, it encompasses all designs and models for 
which a separate standby loss test is warranted and would not 
inadvertently include models that do not need a separate standby loss 
test procedure from other CWH equipment. (Rheem, No. 34 at p. 15)
    DOE disagrees with A.O. Smith's assertion that the definition could 
be unnecessary and cause confusion. On the contrary, DOE believes that 
adopting a definition for flow-activated water heaters will clarify the 
models for which the test procedure for flow-activated

[[Page 79291]]

instantaneous water heaters is applicable. DOE considered the comments 
submitted by Rheem with regard to the language used in the proposed 
definition for ``flow-activated instantaneous water heater.'' DOE notes 
that the purpose of the proposed definition is to carve out water 
heaters that will activate the burner or heating elements only if hot 
water is drawn from the unit. Rheem's recommended wording would include 
any models that activate the burner or heating element when water is 
drawn from the unit, which could include some water heaters that are 
both flow-activated and thermostatically-activated. DOE notes that 
Rheem's suggestion changes the meaning of the proposed text; to achieve 
the same meaning as DOE's proposal would require the addition of 
``only'' (i.e., those water heaters where the burner or heating element 
activates only when water is drawn from the unit). Therefore, DOE 
adopts Rheem's suggestion to remove the double negative from the 
definition, and defines flow-activated water heaters as those that will 
only activate the burner or heating element if water is drawn from the 
unit.
2. Storage Volume Determination for Instantaneous Water Heaters and Hot 
Water Supply Boilers (Excluding Storage-Type Instantaneous Water 
Heaters)
    The existing Federal standby loss test procedure for CWH equipment 
references Exhibit G.2 of ANSI Z21.10.3-2011, which in turn references 
section 2.26 of that standard to measure the storage volume of the 
water heater. The test method in 2.26 of ANSI Z21.10.3-2011 (renumbered 
to 5.27 of ANSI Z21.10.3-2015, the most recent version of the standard) 
is a weight-based method that requires the water heater to be weighed 
empty and then completely filled with water and weighed again. The 
total storage volume in the water heater is calculated using the 
difference in the weight of the water heater when full and empty. The 
2015 version of ANSI Z21.10.3 includes a test method for measuring 
storage volume for tube-type water heaters in section 5.28. DOE 
reviewed this section and noticed that it does not provide a specific 
method to conduct the test and instead only states that the ``volume of 
water contained within the water heater shall be determined.'' In the 
May 2016 NOPR, DOE declined to propose adoption of section 5.28, noting 
that it would leave the decision of the appropriate method (e.g., 
direct measurement, calculation) to individual manufacturers or testing 
agencies, who may choose different methods for determining the storage 
volume, which could produce inconsistent results. Rather, DOE proposed 
to continue using a weight-based test method to measure the storage 
volume of all instantaneous water heaters and hot water supply boilers 
excluding storage-type instantaneous water heaters. 81 FR 28588, 28607-
28613 (May 9, 2016)
    In response to this issue, AHRI, A.O. Smith, Bradley, Bradford 
White, and Rheem opposed DOE's proposal to require use of a test method 
similar to section 5.27 of ANSI Z21.10.3-2015 (i.e., a weight-based 
method), to measure the storage volume of instantaneous water heaters 
and hot water supply boilers (other than storage-type instantaneous 
water heaters). Specifically, AHRI and Bradley commented that they do 
not agree with the proposed test method because it is limited to the 
weight-based test method to determine the volume. Both commenters also 
stated that the determination of volume is critical only to determine 
whether the unit is subject to standby loss standards, and that many 
models currently have their stored water volume determined using 
calculations based on physical dimensions of water-containing parts. 
Both commenters argued that the alternative method of calculating the 
stored water volume based on physical dimensions eliminates the concern 
of residual water encountered in the weight-based test. Furthermore, 
the commenters stated that this method is useful in all cases except 
those with a calculated result that is approximately 10 gallons. (AHRI, 
No. 26 at p. 14; Bradley, No. 33 at pp. 3-4) A.O. Smith commented that 
DOE should accept the rated volume for appliances and allow volume 
determination other than through a weight-based method for small water 
heaters, and recommended using section 5.28 of ANSI Z21.10.3-2015 to 
measure the storage volume. A.O. Smith and Bradford White argued that 
many manufacturers purchase heat exchangers which will have residual 
water left over from hydrostatic testing. A.O. Smith stated that many 
water heaters have water passageways that do not allow the removal of 
water, and that such water heaters are filled for leak and operational 
testing before shipment. Therefore, manufacturers will never be able to 
test a completely dry water heater, thereby leading to inaccuracies in 
the measurement of the storage volume and standby loss. (A.O. Smith, 
No. 27 at p. 12; Bradford White, No. 21 at p. 10) A.O. Smith further 
argued that allowing the use of section 5.28 of ANSI Z21.10.3-2015 
would not prohibit independent test laboratories from using a weight-
based test method when no suitable alternative is available, and that 
manufacturers would be able to use more accurate test methods such as 
solid modeling and calculation-based methods. (A.O. Smith, No. 27 at p. 
12) Bradford White suggested that DOE could include a weight-based test 
procedure for determining storage volume, but that it must include 
steps that include supplying pressurized air and tipping the product in 
different directions to assist the removal of residual water. However, 
Bradford White added that even with these measures, not all the water 
would be removed. (Bradford White, No. 21 at p. 10) Similarly, Rheem 
stated that due to hydrostatic testing, the water heater can never be 
emptied completely, so the dry weight can never be achieved. Rheem 
added that there are different methods of measuring volume of CWH 
equipment allowed by ANSI that include mathematical calculations and 
software modeling. Rheem recommended that DOE allow theoretical methods 
to determine water volume or that DOE set tolerances to account for 
residual water. (Rheem, No. 34 at p. 15)
    DOE generally agrees with the concerns raised by the manufacturers. 
In particular, DOE is concerned that the weight-based test method 
specified in section 5.27 of ANSI Z21.10.3-2015 could lead to 
inaccurate representation of the storage volume due to the presence of 
residual water in the heat exchanger. Therefore, in this final rule, 
DOE is adopting provisions to allow for the determination of stored 
water volume based on calculations of the physical dimensions or design 
drawings (including computer-aided design (CAD) drawings) of the water-
containing parts for instantaneous water heaters and hot water supply 
boilers. Despite the concerns with establishing a specific test method 
to determine the storage volume of instantaneous water heaters and hot 
water supply boilers, DOE notes that it must specify a test method that 
can be used to classify a basic model in the appropriate equipment 
class and to determine the applicable standard. DOE does not agree with 
AHRI's comment that the determination of storage volume is only 
necessary to determine whether the water heater is subject to standby 
loss standards (i.e., whether it has a storage volume greater than or 
equal to 10 gallons). DOE notes that the measured storage volume is 
also required in the equations used to calculate the standby loss of 
CWH

[[Page 79292]]

equipment. Therefore, DOE cannot leave the storage volume determination 
to the discretion of the manufacturer or testing/certifying agency. To 
address this issue, DOE has decided to adopt two test methods, either 
of which may be used to determine the storage volume of instantaneous 
water heaters and hot water supply boilers. Specifically, DOE has 
decided to allow for use of the weight-based test method (similar to 
section 5.27 of ANSI Z21.10.3-2015) as proposed in the May 2016 NOPR as 
one option, and to also permit the use of calculations for determining 
the stored water volume based on the physical dimensions or design 
drawings (including CAD drawings) of water-containing parts. DOE 
believes that these changes are generally consistent with the 
approaches used in ANSI Z21.10.3-2015, as discussed immediately above.
    Along with changes in the test method, DOE is also making a 
corresponding amendment to its certification requirements for CWH 
equipment at 10 CFR 429.44, to require the certification of the method 
used to determine the storage volume of an instantaneous water heater 
or hot water supply boiler. DOE is also updating 10 CFR 429.72 with 
provisions to permit the use of physical dimensions (including design 
drawing and/or CAD models) to determine the storage volume based on 
calculations. In addition, DOE is requiring the retention of 
supplemental documents, including any design drawings and/or computer 
models, as well as documentation of the calculations performed to 
determine the water-carrying parts inside the water heater for any 
water heater models where the storage volume is determined based on 
calculations.
3. Standby Loss Test Procedures for Instantaneous Water Heaters and Hot 
Water Supply Boilers (Other Than Storage-Type Instantaneous Water 
Heaters)
    DOE proposed two separate standby loss test procedures in the May 
2016 NOPR--one for flow-activated instantaneous water heaters, and one 
for instantaneous water heaters and hot water supply boilers (other 
than flow-activated instantaneous water heaters and storage-type 
instantaneous water heaters). 81 FR 28588, 28607-28615 (May 9, 2016). 
The following sections describe the comments received in response to 
the proposed standby loss test methods, along with DOE's response.
    DOE's proposed test method in the May 2016 NOPR would include the 
electricity consumed by the pump in the recirculating loop, if 
applicable, consistent with ANSI Z21.10.3-2015. In response to this 
proposal, Bradford White disagreed with including the electricity 
consumed by the pump in the recirculating loop (if used) in calculating 
the thermal efficiency of CWH equipment, stating that the recirculating 
loop would not be used in the field, and, thus, the pump energy should 
not be considered. (Bradford White, No. 21 at p. 11) DOE notes, 
however, that paragraph h.2 of Exhibit G.1 of ANSI Z21.10.3-2011 
(currently incorporated by reference into DOE's test procedures) and 
Annex E.1 of ANSI Z21.10.3-2015 (the most recent update of the industry 
standard) require the measurement of the quantity of electricity 
consumed by the water heater components and the recirculating pump for 
conducting the thermal efficiency test. In this final rule, DOE is not 
promulgating a different set of requirements, instead DOE is only 
retaining the provisions that already exist in the current test 
procedure for electricity consumed by the recirculating loop. 
Therefore, DOE does not agree with Bradford White's suggestion that the 
energy used by the recirculating pump should not be measured for any 
type of water heater because this is part of the industry recognized 
test procedure in ANSI Z21.10.3.
a. Applicability of the Test Method
    AHRI, A.O. Smith, and Rheem commented that the proposed test 
procedure for instantaneous water heaters and hot water supply boilers 
other than flow-activated instantaneous water heaters will not work for 
models that the test procedure intends to cover. (AHRI, No. 26 at p. 
11; A.O. Smith, No. 27 at p. 14; Rheem, No. 34 at p. 17) AHRI and Rheem 
stated that many models, although not flow-activated, will act like a 
flow-activated instantaneous water heater during the standby loss test 
for which there will be no cut-in and subsequent cut-out. AHRI and 
Rheem recommended that the test procedure proposed for flow-activated 
instantaneous water heaters apply to all instantaneous water heaters 
and hot water supply boilers (other than storage-type instantaneous 
water heaters). (AHRI, No. 26 at p. 11; Rheem, No. 34 at p. 17) A.O. 
Smith stated that circulating instantaneous water heaters are primarily 
operated based on a remote temperature sensor, which is not mentioned 
in DOE's test method and is presumed to be left in a state that would 
require the burner to fire continuously. (A.O. Smith, No. 27 at p. 14) 
Raypak commented that the equation presented in the NOPR for the 
standby loss test procedure for instantaneous water heaters and hot 
water supply boilers can result in negative standby loss values if the 
unit does not fire at any point during the standby loss test. (Raypak, 
No. 28 at p. 3) Lochinvar sought feedback on how the test method would 
work for instantaneous water heaters that do not have an internal call 
for heating. Specifically, Lochinvar stated that instantaneous water 
heaters that do not have a call for heating internally require an 
outside thermostat or aquastat to provide a call for heating, and that 
for such water heaters, there will be no second call for heating to end 
the test based on the proposal in the May 2016 NOPR. (Lochinvar, Public 
Meeting Transcript, No. 20 at p. 97)
    DOE also received several comments that related only to the 
proposed test procedure for flow-activated instantaneous water heaters. 
A.O. Smith commented that the proposed test procedure for flow-
activated instantaneous water heaters is not necessary and may cause 
confusion. A.O. Smith suggested that the test methods for all 
instantaneous water heaters and hot water supply boilers must be 
consistent, adding that demand-based controls and lack of a storage 
tank makes the traditional standby loss test impossible to use. To 
address this issue, A.O. Smith suggested a standby loss test that 
incorporates demand-based operation and measures inlet and outlet 
temperature, and stated that, if DOE does not accept the test procedure 
in ANSI Z21.10.3-2015, then the test procedure proposed for flow-
activated instantaneous water heaters should be applied to all 
instantaneous water heaters and hot water supply boilers. A.O. Smith 
added that a common thermal efficiency and standby loss test should be 
used for both the flow-activated instantaneous water heaters and 
temperature-activated instantaneous water heaters to ensure a level 
playing field, and that no special arrangements are required for flow-
activated instantaneous water heaters. (A.O. Smith, No. 27 at pp. 11-12 
and 15) Rheem supported the proposal to base the test procedure for 
flow-activated instantaneous water heaters on the second part of the 
2016 AHRI-recommended test method with some modifications. (Rheem, No. 
34 at p. 16) Conversely, Bradley commented that it does not support 
basing the flow-activated instantaneous water heater standby loss test 
method on the second part of the 2016 AHRI-recommended test method; 
instead, it recommended using an alternative test method

[[Page 79293]]

described in its comments. (Bradley, No. 33 at p. 4)
    Based on the comments, it appears that instantaneous water heaters 
and hot water supply boilers can be categorized into three major 
categories based on the kind of feedback-control operation used: (1) 
Thermostatically-activated based on an internal call for heating 
(internally-activated instantaneous water heaters); (2) 
thermostatically-activated based on an external call for heating; and 
(3) flow-activated based on an external call for heating. As discussed 
previously, in the May 2016 NOPR, DOE proposed separate standby loss 
test procedures for flow-activated instantaneous water heaters (81 FR 
28588, 28607-28613 (May 9, 2016)) and for instantaneous water heaters 
(excluding storage-type instantaneous water heaters) that are not flow-
activated (81 FR 28588, 28615-28617 (May 9, 2016)). The standby loss 
test procedure proposed for instantaneous water heaters and hot water 
supply boilers that are not flow-activated only addressed units that 
are thermostatically-activated by an internal call for heating (or 
demand) and did not address units that are thermostatically-activated 
by an external call for heating. DOE agrees that the test procedure 
proposed for instantaneous water heaters and hot water supply boilers 
(other than storage-type instantaneous water heaters) that are not 
flow-activated, as proposed in the May 2016 NOPR, would not work for 
units that are thermostatically-activated based on an external call for 
heating. DOE understands that, for field applications of units that are 
activated by an external demand, the thermostat is typically placed in 
a remote location, such as in an unfired hot water storage tank, and is 
activated when the water in the tank cools down below the set point. In 
the context of the proposed standby loss test, unless the external 
control provides a call for heating (such a call for heating is not 
specified in either the existing or proposed standby loss test), the 
unit under test would not activate the burner or heating element during 
the standby loss test. Thus, the standby loss test proposed for 
instantaneous water heaters and hot water supply boilers (other than 
flow-activated instantaneous water heaters) would not be applicable to 
instantaneous water heaters that are thermostatically-activated by an 
external demand, because these units would not experience a call for 
heating, and therefore the burner or heating element(s) would not 
activate during the test. The test method for determining the standby 
loss of flow-activated instantaneous water heaters was designed to 
address units where the burner or heating element(s) may not activate 
during the test. Considering the comments received from the 
stakeholders, DOE agrees that the standby loss test procedure proposed 
for flow-activated instantaneous water heaters in the May 2016 NOPR can 
be used for externally thermostatically-activated instantaneous water 
heaters, as neither of these types of water heater would cut-in (i.e., 
have the heating element or burner turn on) during the standby loss 
test. Therefore, DOE is making the test method adopted in this final 
rule for flow-activated instantaneous water heaters apply to externally 
thermostatically-activated instantaneous water heaters as well.
    To address operational characteristics of externally 
thermostatically-activated instantaneous water heaters, the proposed 
standby loss test procedure in the May 2016 NOPR for flow-activated 
instantaneous water heaters must be modified slightly. These amendments 
include: (1) Adding provisions that require either removing the 
external call for heating, or turning off the fuel supply to the 
burners or electricity supply to the heating element (as applicable) 
after the steady-state conditions as specified in section III.F.1 are 
achieved prior to initiating the standby loss test; and (2) removing 
the fuel consumption terms from the equation to calculate the standby 
loss. Adopting the provisions to remove the external call for heating 
or turn off the fuel and electricity will ensure that there will be no 
fuel consumption (or electricity consumption for the purpose of heating 
water) during the course of the standby loss test. Therefore, the 
equations would not require the fuel consumption terms in the 
calculation for standby loss.
    To simplify the regulatory text, DOE has decided to include all 
test procedures related to gas-fired and oil-fired instantaneous water 
heaters and hot water supply boilers under one appendix (i.e., appendix 
C to subpart G of part 431). This differs from the approach proposed in 
the May 2016 NOPR, which would have provided a separate appendix for 
gas-fired and oil-fired instantaneous water heaters and hot water 
supply boilers other than flow-activated instantaneous water heaters 
(proposed appendix C) and flow-activated instantaneous water heaters 
(proposed appendix E). Within appendix C adopted in this final rule, 
the thermal efficiency test and the steps prior to starting the standby 
loss test (e.g., for verifying steady-state conditions) are common to 
all gas-fired and oil-fired instantaneous water heaters and hot water 
supply boilers. The standby loss tests for (1) thermostatically-
activated instantaneous water heaters with internal thermostat; and (2) 
thermostatically-activated instantaneous water heaters with external 
thermostat and flow-activated instantaneous water heaters are described 
separately in the regulatory text.
    In the May 2016 NOPR, DOE also proposed standby loss test 
procedures for electric instantaneous water heaters (contained in 
proposed appendix D) and electric flow-activated instantaneous water 
heaters (contained in proposed appendix E). 81 FR 28588, 28649-28650 
(May 9, 2016). In this final rule, DOE has decided to include the 
standby loss test procedures for all electric instantaneous water 
heaters in appendix D to subpart G of part 431. Similar to the 
structure in appendix C, the steps in the standby loss test procedure 
prior to initiating the measurements for the standby loss test are the 
same for all electric instantaneous water heaters. The steps describing 
the conduct of the standby loss test are different for internally 
thermostatically-activated electric instantaneous water heaters and 
those that are either externally thermostatically-activated or flow-
activated.
b. Applicability to Models With Less Than 10 Gallons of Stored Water 
Volume
    In the May 2016 NOPR, DOE proposed standby loss test procedures for 
all gas-fired, oil-fired, and electric instantaneous water heaters and 
did not limit the use of the test procedure to less than 10 gallons of 
rated storage volume. 81 FR 28588, 28607, 28615 (May 9, 2016).
    In response, Bradford White stated that it agrees with adopting a 
standby loss test applicable to units with rated storage volume less 
than 10 gallons, only if compliance with maximum standby loss standards 
is not required for such units. (Bradford White, No. 21 at p. 11) 
Bradley stated that flow-activated instantaneous water heaters having 
capacity less than 10 gallons contain little thermal energy, and that 
developing a test procedure for such units is unnecessary. According to 
Bradley, the thermal energy loss of their electric-instantaneous flow-
activated models with less than 10 gallons of storage capacity is less 
than 600 Btu/h (157 Watts). Bradley stated that these units will not 
function effectively unless water in the unit is minimized and that 
typically these units contain small volumes--often less than two 
gallons of water. Bradley argued that, due to low

[[Page 79294]]

volumes, the units have a very limited amount of stored energy, and 
suggested that DOE should simplify the test method based on an 
assumption that the temperature of the water stored in the unit will 
drop to the ambient temperature within a one-hour time period. Bradley 
further stated that due to the nature of its water heaters, the burden 
to test them for standby loss would be high, while not resulting in any 
meaningful energy savings, but that its suggested clarifications and 
simplifications to the test procedure would help in reducing the 
burden. (Bradley, No. 33 at pp. 1-3)
    In response to these comments, DOE notes that the current maximum 
standby loss standards for instantaneous water heaters are only 
applicable to gas-fired and oil-fired instantaneous water heater models 
with rated storage volume greater than or equal to 10 gallons. 10 CFR 
431.110. Therefore, manufacturers are currently not required to test 
and certify their instantaneous water heaters and hot water supply 
boilers for standby loss, if the model has a rated storage volume less 
than 10 gallons. DOE further notes that in the NOPR for energy 
conservation standards for CWH equipment that was published in the 
Federal Register on May 31, 2016, DOE did not propose to prescribe 
standby loss standards for electric instantaneous water heaters and 
gas-fired and oil-fired instantaneous water heaters with rated storage 
volume less than 10 gallons. 81 FR 34440. Although in this test 
procedure final rule, DOE is prescribing a test procedure that could be 
used to test all instantaneous water heaters for standby loss, 
manufacturers are not required to test and certify units that are not 
subject to energy conservation standards. However, if a manufacturer 
chooses to make representations for standby loss for an instantaneous 
water heater or hot water supply boiler with a rated storage volume 
less than 10 gallons, then it must do so using DOE's test procedures 
specified in Appendix C or Appendix D to subpart G of part 431 (as 
applicable). In this final rule, DOE is adopting standby loss test 
procedures for all gas-fired, oil-fired, and electric instantaneous 
water heaters without limiting its applicability based on rated storage 
volume.
    DOE also considered the simplified test method suggested by Bradley 
in its comments. The test procedure suggested by Bradley restricts the 
time period of the standby loss test to one hour and removes the 
electricity consumption terms from the standby loss equation. DOE 
addressed similar issues related to the test duration in the May 2016 
TP NOPR, in which it discussed the disadvantages of having a set time 
duration to conduct the standby loss test. 81 FR 28588, 28611 (May 9, 
2016) As discussed in the May 2016 NOPR, the standby mode operation of 
flow-activated instantaneous water heaters resembles a complete cool-
down test where the main burner or heating element does not activate at 
any point during the test. Simply assuming that the water heater loses 
all stored thermal energy over a one-hour period ignores the fact that 
the rate of heat loss is dependent on the insulation and design of the 
water heater itself, and models with different insulation thicknesses 
and heat exchanger designs will lose heat at different rates. 81 FR 
28588, 28611 (May 9, 2016). Accordingly, if the duration of the test 
were set to one hour, this could lead to an inaccurate comparison of 
the standby loss between two water heaters that lose heat at different 
rates because some water heaters may reach ambient temperature much 
more quickly than that and others much more slowly. For example, a 
water heater that cools to ambient temperature in 5 minutes would have 
the same standby loss rating as a water heater that reaches ambient in 
a period of 50 minutes. In addition to yielding the same standby loss 
for two models that would otherwise have significantly different 
standby loss ratings, the assumption would likely understate the 
standby loss by assuming the loss occurs over the full duration of an 
hour, rather than the actual amount of time it takes for the thermal 
energy to be lost, which according to Bradley is generally less than an 
hour. The suggested simplified test method also does not account for 
electrical consumption during the course of the test. The electrical 
consumption during the standby loss test is mainly due to electricity 
provided to keep the controls and non-water-heating functions running 
during the standby loss test. This electricity consumption is also 
accounted for in the current standby loss equations in the test 
procedures in Exhibit G.2 of ANSI Z21.10.3-2011, incorporated by 
reference as DOE's standby loss test procedure for storage and 
instantaneous water heaters and set forth in 10 CFR 431.106. Therefore, 
in this final rule, DOE has decided not to make changes to its proposed 
standby loss equations based on the comments provided by Bradley.
c. Turning Off Supply and Outlet Water Valves Simultaneously
    The standby loss test procedures for flow-activated instantaneous 
water heaters and all other instantaneous water heaters and hot water 
supply boilers (except storage-type instantaneous water heaters) 
proposed in the May 2016 NOPR required the water pump and supply and 
outlet water valves to be shut off simultaneously to start the standby 
loss test. 81 FR 28588, 28607, 28615 (May 9, 2016) This proposal was 
related to DOE's tentative decision in the May 2016 NOPR to install the 
supply water valve at a distance of 5 inches away from the water heater 
in the supply water connection and the outlet water valve at a distance 
of 10 inches away from the water heater in the outlet water connection 
in order to reduce the effect of heat loss due to mixing with water in 
the piping during the standby loss test. 81 FR 28588, 28613-28615 (May 
9, 2016). DOE received several comments on the placement of the supply 
and outlet water valves that are discussed and addressed in section 
III.I.3 of this final rule. The following paragraphs discuss the 
comments received with regard to turning off the supply and outlet 
water valves simultaneously at the start of the standby loss test.
    AHRI, A.O. Smith, Bradford White, and Raypak opposed the proposed 
requirement that the supply water valve and outlet water valve (and 
water pump) be turned off simultaneously when initiating the standby 
loss test for instantaneous water heaters and hot water supply boilers. 
The commenters stated that the proposed test method may lead to unsafe 
operating conditions and/or may trigger the relief valve to open if the 
water heater burner or elements activate to satisfy a call for heating 
during the standby loss test. AHRI, A.O. Smith, Bradford White, Raypak, 
and Rheem recommended that only the outlet water valve be closed at the 
start of the standby loss test and the supply valve be kept open at all 
times. (AHRI, No. 26 at p. 11; A.O. Smith, No. 27 at p. 13; Bradford 
White, No. 21 at p. 11; Raypak, No. 28 at p. 3; Rheem, No. 34 at p. 16) 
AHRI and Rheem stated that the outlet valve is sufficient to stop the 
flow while allowing thermal expansion to occur during the test. (AHRI, 
No. 26 at p. 11; Rheem, No. 34 at p. 16) Similarly, A.O. Smith 
commented that, if there is heat added to the heat exchanger after the 
flow is stopped, there must be an allowance for thermal expansion of 
the water. A.O. Smith added that in the proposed test procedure, the 
closing of the supply and outlet water valves isolates the water 
heater, and if the control is set to a call for heating at all times, 
the water heater may continue to fire until the water temperature 
reaches the high safety limit. This could result in the formation

[[Page 79295]]

of superheated steam and blow off the pressure relief valve. (A.O. 
Smith, No. 27 at pp. 14-15)
    DOE agrees with the comments received from the stakeholders citing 
safety concerns while conducting the standby loss test as proposed in 
the May 2016 NOPR. To address this issue, DOE has decided to remove the 
requirement to turn off the supply water valve during the conduct of 
the standby loss test. Instead, the standby loss test procedures 
adopted for instantaneous water heaters and hot water supply boilers 
only require turning off the outlet water valve and the water pump at 
the start of the test. DOE has also made several amendments to its test 
set-up proposed in the May 2016 NOPR, including ones related to the 
standby loss test procedure. These amendments and the related comments 
are discussed in section III.I of this final rule.
d. Approximation of Stored Water Temperature Based on Water Temperature 
at the Outlet
    As discussed previously, in the May 2016 NOPR DOE tentatively 
decided to use the outlet water temperature as an approximation for the 
mean tank temperature to conduct the standby loss test for flow-
activated instantaneous water heaters and other instantaneous water 
heaters (except for storage-type instantaneous water heaters). 81 FR 
28588, 28607, 28615 (May 9, 2016).
    In response to this proposal, Raypak stated that because DOE 
proposed not to adopt the test procedures in ANSI Z21.10.3-2015 for 
flow-activated instantaneous water heaters and instantaneous water 
heaters and hot water supply boilers (other than flow-activated 
instantaneous water heaters and storage-type instantaneous water 
heaters), it does not support the use of outlet water temperature as a 
conservative estimate for the mean tank temperature. Instead, Raypak 
recommended using the average of the supply and outlet water 
temperature (Raypak, No. 28 at p. 4) Raypak also stated that it 
supported DOE's decision to not use an external tank to measure the 
mean tank temperature. (Raypak, No. 28 at p. 7) Rheem also recommended 
that instead of using the outlet water temperature as an approximation 
for the stored water temperature, DOE use an average of the inlet and 
outlet water temperature. Rheem added that DOE's proposal is better 
suited for gas-fired flow-activated instantaneous water heaters than 
for electric flow-activated instantaneous water heaters. (Rheem, No. 
34, at pp. 16-17) Bradley supported using the outlet water temperature 
as an approximation for the stored water temperature, but also 
reiterated that the calculation of standby loss for water heaters with 
very low volume is wasteful, burdensome, and unnecessary (see section 
III.H.3.b for further discussion of Bradley's comment on standby loss 
for water heaters with very low volumes). (Bradley, No. 33 at p. 4) The 
Joint Advocates supported DOE's determination that outlet water 
temperature is an appropriate reference for the standby loss test 
(rather than the mean tank temperature). (Joint Advocates, No. 32 at p. 
2)
    A.O. Smith stated that the assumption that stored water temperature 
is the key to standby loss for instantaneous water heaters does not 
take into consideration that: (1) More heat may be stored in the heat 
exchanger than the water itself; (2) there is a non-uniform water 
temperature in the heat exchanger which increases from inlet to outlet; 
and (3) gravity circulation may lead to a decrease in the outlet water 
temperature that is not due to the heat loss to the atmosphere. A.O. 
Smith suggested using the average of the inlet and outlet water 
temperature to approximate the stored water temperature. (A.O. Smith, 
No. 27 at p. 13)
    DOE also received several comments on this issue at the NOPR public 
meeting. Bradley stated that for electric instantaneous water heaters 
with a 70 [deg]F inlet and 140 [deg]F outlet, assuming the outlet water 
temperature as an approximation for stored water temperature would be a 
large penalty. However, Bradley also agreed that inserting temperature 
probes in the heat exchanger would be difficult. (Bradley, Public 
Meeting Transcript, No. 20 at p. 103) AHRI stated that inserting a 
temperature probe inside the heat exchanger is difficult and suggested 
that the outlet water temperature probe be used as point of reference 
for the standby loss test since a temperature probe is already required 
for measurement of the water close to the outlet of the water heater in 
the thermal efficiency test. (AHRI, Public Meeting Transcript, No. 20 
at pp. 104-105)
    In the May 2016 NOPR, DOE considered several options for estimating 
the stored water temperature inside the water heater for developing the 
proposed standby loss test procedure for instantaneous water heaters 
and hot water supply boilers. 81 FR 28588, 28616 (May 9, 2016). Among 
the options, DOE considered using an average of the supply and outlet 
water temperature as an estimation of the stored water temperature 
inside the heat exchanger. DOE weighed this option against the option 
of using the outlet water temperature as an approximation for the 
stored water temperature inside the heat exchanger. Ultimately, DOE 
proposed to use the outlet water temperature as an approximation, 
because it was included in the industry-adopted test method for flow-
activated instantaneous water heaters, specifically in Annex E.3 of 
ANSI Z21.10.3-2015. DOE notes that using the average of the supply and 
outlet water temperature as an estimate for the stored water 
temperature is only valid if the water temperature inside the heat 
exchanger has a linear increase in temperature as it moves from the 
inlet to the outlet. Considering the kinds of heat exchangers that are 
typically used in instantaneous water heaters and hot water supply 
boilers (e.g., fin-tube, helical condensing heat exchangers), DOE does 
not believe this assumption to be valid. Instead, DOE expects that the 
mass-weighted average temperature of the water inside the heat 
exchanger is likely to be higher than the simple average of the water 
temperature between the supply and the outlet, because the rate of heat 
transfer from the burner to the water decreases as the water 
temperature rises in the heat exchanger. Therefore, as the water moves 
through the heat exchanger and approaches the required outlet water 
temperature, it takes longer for its temperature to rise further, and 
thus, the mass-weighted average of the water in the heat exchanger is 
higher than the simple average between supply and outlet water 
temperature.
    DOE agrees that using the average between the supply and outlet 
water temperature is a simple approach; however, this method is not 
sufficiently accurate to represent the temperature of water stored in 
the heat exchanger. Further, inserting probes deep inside the heat 
exchanger to accurately capture the stored water temperature would 
result in a more accurate reading of the water temperature within the 
heat exchanger, but would be significantly burdensome to achieve and 
difficult to ensure consistency in the placement of the temperature 
sensor, thereby decreasing repeatability. Using the outlet water 
temperature as an approximation for the stored water temperature should 
be more representative of the stored water temperature than using a 
simple average between the supply and outlet water temperature and less 
burdensome than inserting probes deep inside the heat exchanger. After 
careful consideration and based on the discussion above, DOE is not 
adopting the simple average of the supply and outlet water temperature 
as

[[Page 79296]]

an approximation for the stored water temperature. Instead, the outlet 
water temperature serves as an approximation for the stored water 
temperature. This is consistent with the industry test method specified 
in Annex E.3 of ANSI Z21.10.3-2015 and provides for a conservative test 
result where a large amount of uncertainty exists in estimating the 
stored water temperature in the heat exchanger.
e. Pump Purge
    The proposed standby loss test procedure for instantaneous water 
heaters and hot water supply boilers (including the proposed test 
procedure for flow-activated instantaneous water heaters) in the May 
2016 NOPR would require the test to be initiated immediately after 
turning off the supply and outlet water valves and water pump. 81 FR 
28588, 28613 (May 9 2016).
    DOE received several comments from stakeholders opposing a 
requirement to start the test immediately following the close of the 
supply and outlet water valves and the water pump. Specifically, Raypak 
argued that the proposed test procedure for instantaneous water heaters 
and hot water supply boilers does not take into consideration pump 
purge functionality,\15\ and there are several models on the market 
that include such functionality. Raypak recommended that the standby 
loss test be started only after the pump purge period has ended. 
(Raypak, No. 28 at pp. 3,4,7; Raypak, Public Meeting Transcript, No. 20 
at p. 90) Rheem stated that post-purge operation of the water heater 
needs to be addressed in the test procedure because the functionality 
is used to reduce standby loss by removing residual heat from the water 
heater. (Rheem, No. 34 at p. 16) AHRI stated that some models use pump 
purge to remove heat from a water heater that is used to service the 
hot water system, so the standby loss test should not start until the 
pump purge operation is complete. (AHRI, No. 26 at p. 12) A. O. Smith 
stated that many instantaneous water heaters have an integral pump with 
a delay that continues to circulate water through the heat exchanger 
for a limited time (30 seconds to 3 minutes) to move residual hot water 
from the heat exchanger to the storage tank. A. O. Smith recommended 
that the outlet water valve and water pump be turned off after the pump 
delay is complete. (A. O. Smith, No. 27 at p. 13)
---------------------------------------------------------------------------

    \15\ Pump purge functionality allows the water pump to remain on 
for a short period after the main burner cuts out, which purges 
heated water from the unit, thereby reducing standby losses.
---------------------------------------------------------------------------

    DOE agrees with commenters that pump purge functionality is useful 
in removing the hot water stored in the water heater for use in the 
system. Thus, DOE also agrees with the recommendations from the 
stakeholders that the unit should be tested after the pump purge has 
ended. To accommodate pump purge operation, DOE will require the outlet 
water valve to remain open after the burner has cutout until the water 
pump has turned off. Further, DOE will require the loss in thermal 
energy recorded during the standby loss test and represented by the 
temperature difference term [Delta]T1, to be measured after 
the pump purge operation ends. Specifically, DOE modifies the 
definition of the term `[Delta]T1' to refer to the heat 
exchanger outlet water temperature measured at the end of pump purge 
minus the heat exchanger outlet water temperature measured at the end 
of the test.
    Therefore, in this final rule DOE adopts the following updates to 
the standby loss test for instantaneous water heaters and hot water 
supply boilers that are equipped with pump purge functionality: (1) 
Require the outlet valve to remain open until the pump purge operation 
is complete and then close the outlet water valve after the pump shuts 
down; (2) measure the thermal energy loss after the pump purge 
operation is complete and (3) end the standby loss test after the pump 
purge operation is completed and when the heat exchanger outlet water 
temperature has decreased by 35 [deg]F from its value measured at the 
start of the test (i.e., starting from the point when the main 
burner(s) or heating element(s) cut-out). If, after a pump purge 
operation, the outlet water temperature has dropped by 35 [deg]F or 
more, from its value after the burner(s) or heating element(s) cuts-
out, then the test must be stopped after the pump purge is complete. 
All the required parameters must be recorded for the entire standby 
loss test, including the pump purge operation.
    Considering the comments received, DOE revises the standby loss 
test procedure proposed in the May 2016 NOPR for flow-activated 
instantaneous water heaters to include additional provisions that 
account for pump purge functionality. DOE adds a requirement to measure 
the heat exchanger outlet water temperature immediately after the main 
burner(s) or heating element(s) cut out and clarifies that the outlet 
water valve must be kept open until the water pump shuts down. After 
the water pump shuts down, the outlet water valve must be closed and 
the recording of all required parameters for the standby loss test is 
started. The test is stopped once the heat exchanger outlet water 
temperature decreases by 35 [deg]F from the temperature measured when 
the burner(s) or heating element(s) cut-out before the pump purge 
operation. DOE has included these modifications to the test procedure 
in Appendix C (for gas-fired and oil-fired equipment) and Appendix D 
(for electric equipment) to subpart G of part 431.
    DOE also adopts provisions at 10 CFR 429.44 to require certifying 
whether the unit has pump purge functionality. These amendments are 
discussed further in section III.N of this final rule.
f. Temperature Rise Requirement and End of Test Criteria for 
Instantaneous Water Heaters
    The proposed standby loss test procedures for instantaneous water 
heaters and hot water supply boilers (including flow-activated and 
externally thermostatically-activated instantaneous water heaters) 
would require water to be supplied at a temperature of 70 [deg]F  2 [deg]F; the fuel supply to be at the unit's full firing rate; 
and the water flow rate to be adjusted to achieve and maintain 70 
[deg]F  2 [deg]F above the supply water temperature before 
achieving steady-state condition prior to the standby loss test. 81 FR 
28588, 28613 (May 9, 2016). The proposed standby loss test for flow-
activated and externally thermostatically activated instantaneous water 
heaters would be stopped once the outlet water temperature decreases by 
35 [deg]F  2 [deg]F Id. at 28612-28613. DOE received 
several comments on the criteria for determining the end of the test 
and the requirement to achieve steady state with a temperature rise of 
70 [deg]F  2 [deg]F.
    With regard to the criteria for determining the end of the standby 
loss test, A. O. Smith stated that the 35 [deg]F  2 [deg]F 
decrease in outlet water temperature is inappropriate because a greater 
proportion of heat is stored in the mass of the heat exchanger rather 
than the water stored in the heat exchanger, which according to A. O. 
Smith is not equal to the outlet water temperature. A. O. Smith further 
stated that internal circulation within the water heater equalizes the 
temperature in the heat exchanger without actually losing heat to the 
ambient air. (A. O. Smith, No. 27 at pp. 12-13). Bradley supported the 
35 [deg]F drop in outlet water temperature as the criterion for ending 
the test, but noted that for water heaters with small volumes, the 
decrease in outlet water temperature will be due to

[[Page 79297]]

internal mixing and not losses to the ambient air. (Bradley, No. 33 at 
p. 1-3)
    In the May 2016 NOPR, DOE considered the merits of establishing a 
specific temperature decrease criterion to stop the standby loss test 
as compared to a specific time duration. 81 FR 28588, 28611-28612 (May 
9, 2016). In the May 2016 NOPR DOE noted that setting a specific time 
criterion ignores the fact that different water heaters could lose heat 
to the ambient air at different rates. Although DOE recognizes A. O. 
Smith's concerns regarding heat contained in the heat exchanger and 
possible mixing, DOE notes that the commenter did not suggest an 
alternative stopping criterion. Furthermore, DOE maintains its 
conclusion and rationale from the NOPR that setting a specific time 
criterion is not appropriate, and agrees with Bradley that a 35 [deg]F 
drop in outlet water temperature as the criterion for ending the test 
is appropriate. Therefore, in this final rule, DOE has decided to adopt 
the proposed stopping criteria: That the standby loss test for all 
externally thermostatically-activated and flow-activated instantaneous 
water heaters be stopped when the outlet water temperature decreases by 
35 [deg]F  2 [deg]F (as was proposed in the May 2016 NOPR 
for flow-activated instantaneous water heaters).
    On the issue of achieving an outlet water temperature of 70 [deg]F 
 2 [deg]F above the supply water temperature, Bradley 
stated that certain of its water heater models have physical and 
tertiary temperature limit safety devices that cannot be safely 
overridden and will not be able to meet the proposed 140 [deg]F outlet 
temperature condition. (Bradley, No. 33 at p. 4) Rheem and AHRI 
commented that certain water heating technologies cannot achieve the 70 
[deg]F temperature rise to reach the 140 [deg]F outlet water 
temperature condition, and suggested the use of 70 [deg]F temperature 
rise or the maximum designed outlet water temperature, whichever is 
greater. (Rheem, No. 34 at p. 16; AHRI, No. 26 at p. 11)
    In response, DOE acknowledges the concerns raised and adopts the 
changes suggested by AHRI and Rheem with regards to instantaneous water 
heaters that are unable to achieve the required outlet water 
temperature due to in-built safety mechanisms. In this final rule, DOE 
adopts provisions that would allow such units to be tested using the 
maximum outlet water temperature that the unit is capable of achieving.

I. Test Set-Up for Commercial Instantaneous Water Heaters and Hot Water 
Supply Boilers

    In the May 2016 NOPR, DOE proposed several amendments to the 
current test set-up for commercial instantaneous water heaters and hot 
water supply boilers (including flow-activated instantaneous water 
heaters). These proposed amendments include: (1) Specifying the 
location for measuring the outlet water temperature; (2) specifying the 
location for placing the supply and outlet water valves; (3) adding 
provisions for commercial equipment with multiple outlet water 
connections; and (4) adding conditions for using a recirculating loop. 
81 FR 28588, 28613-28615 (May 9, 2016). DOE received several comments 
from manufacturers and industry representatives in response to each 
proposed amendment in the test set-up, which are discussed in detail in 
the sections immediately below.

1. Location of Outlet Water Temperature Measurement

    The existing thermal efficiency and standby loss test methods as 
described in ANSI Z21.10.3-2011 and incorporated by reference into 
DOE's test procedures at 10 CFR 431.107 require commercial 
instantaneous water heaters and hot water supply boilers to be set up 
in accordance with Figure 2 of ANSI Z21.10.3-2011. Neither Figure 2 nor 
the text of DOE's test method, provide an exact location for measuring 
the outlet water temperature. If the outlet water temperature is 
measured at a significant distance away from the water heater, it could 
lead to an inaccurate representation of the outlet water temperature 
due to heat loss in the piping, particularly during the standby loss 
test. Thus, to ensure consistency and repeatability of the test, in the 
May 2016 NOPR, DOE proposed to specify a requirement for the distance 
of the outlet temperature sensor from the water heater jacket. Further, 
in the May 2016 NOPR, DOE proposed to use the outlet water temperature 
as an approximation for the temperature of stored water contained in 
the heat exchanger. Therefore, it was important in the context of the 
May 2016 NOPR proposal that the outlet water temperature be measured as 
close as possible to the water heater to minimize the effect of piping 
heat losses and to obtain a more accurate approximation of the stored 
water temperature inside the heat exchanger, while conducting the 
standby loss test. Specifically, in the May 2016 NOPR, DOE proposed 
that the tip or junction of the temperature sensor be placed at a 
distance of less than or equal to 5 inches from the water heater 
jacket, at the central axis of the water pipe, and with a radiation 
protection shield. The proposal left the type and number of 
temperature-sensing instruments to the discretion of the testing 
operator. 81 FR 28588, 28614 (May 9, 2016).
    Bradford White, AHRI, A. O. Smith, Raypak, Rheem, and Lochinvar 
disagreed with DOE's proposed location for measuring the outlet water 
temperature for both the thermal efficiency and standby loss tests. The 
commenters argued against moving the outlet water temperature sensor 
from its current location, because the current location includes two 
elbows in the outlet water piping connection, before the outlet water 
temperature measurement, which induces turbulent flow and improves 
mixing of water in the pipes, leading to a better representation of the 
outlet water temperature. (Bradford White, No. 21 at p. 10; AHRI, No. 
26 at p. 10-11; A. O. Smith, No. 27 at p. 14; Raypak, No. 28 at p. 3; 
Rheem, No. 34 at p. 17; Lochinvar, Public Meeting Transcript, No. 20 at 
p. 87) Bradford White stated that measuring the outlet water 
temperature a significant distance away from the water heater would not 
lead to an inaccurate representation unless the pipes are poorly 
insulated. (Bradford White, No. 21 at p. 10) Raypak commented that 
requiring the outlet water temperature sensor to be within 5 inches of 
the water heater during the thermal efficiency test would make the 
measurement extremely difficult or physically impossible, especially 
for larger fuel input rates. However, Raypak suggested that, for the 
standby loss test, the outlet water temperature could be measured at 
the outlet or possibly inside the water heater jacket, and recommended 
adopting separate test set-up figures for conducting the thermal 
efficiency and standby loss tests. (Raypak, No. 28 at pp. 3-4) Bradford 
White suggested requiring additional thermocouples to be inserted into 
the outlet of the water heater for the standby loss test. (Bradford 
White, No. 21 at p. 10) AHRI also suggested adding another temperature-
sensing means, and suggested that it be installed one-inch inside the 
water heater's outlet to measure the maximum temperature of the water 
in the unit. (AHRI, No. 26 at p. 11) Raypak stated that as a unit size 
increases, it may become increasingly difficult to add temperature-
sensing means and water valves at the distances proposed in the May 
2016 NOPR, and recommended that DOE consider

[[Page 79298]]

specifying the locations in terms of pipe diameters rather than exact 
distances. (Public Meeting Transcript, No. 20 at pp. 86-87)
    AHRI recommended that DOE require an instantaneous water heater to 
be tested using the test set up in figures 1, 2 and 3 proposed for 
storage water heaters in the May 2016 NOPR (see 81 FR 28588, 28599-
28600). (AHRI, No. 26 at p. 10)
    Bradley Corporation suggested that the requirements for test set-up 
should include the phrase ``water heater jacket or enclosure,'' to 
specify the location for measuring ambient room temperature, test air 
temperature, ambient relative humidity, and air draft, because there 
are no jackets for instantaneous water heaters. (Bradley, NOPR Public 
Meeting Transcript, No. 20 at p. 33) After considering these comments, 
DOE has decided to retain the two elbow fittings in the outlet water 
piping before the outlet water temperature measurement for the thermal 
efficiency test, as DOE agrees with the suggestions from the commenters 
that the elbows will improve the water mixing and allow for a more 
accurate measurement of the outlet water temperature during the thermal 
efficiency test. Nevertheless, DOE continues to believe that specifying 
the distance of the measurement from the water heater will improve 
repeatability without adding burden to the test, as it will ensure 
consistent placement of the outlet water temperature sensor. As a 
result, DOE has modified Figure III.4 as proposed in the May 2016 NOPR 
to require the outlet water temperature sensor be installed at the 
second elbow in the outlet water piping for the thermal efficiency 
test. DOE is also adopting AHRI's recommendation to permit the use of 
the test set-ups specified in Figure III.1, Figure III.2, and Figure 
III.3 of the May 2016 NOPR (and shown as figures 2.1, 2.2, and 2.3 in 
Appendix A to subpart G in the regulatory text of this document) to 
test instantaneous water heaters that do not require a recirculating 
loop for testing (see section III.I.5). As a result, DOE has also 
modified the piping configuration in Figure III.4 of the May 2016 NOPR 
to match the total piping lengths specified for the test set-up for 
water heaters with horizontal opening water connections (as shown in 
Figure III.3 of this final rule). Specifically, DOE is specifying a 
measurement location for the outlet water temperature sensor, similar 
to storage water heaters at a horizontal piping length of 6 inches and 
vertical piping length of 24 inches from the outlet port of the water 
heater. These distances are comparable to the distances specified for 
storage water heaters and address Rheem's concern about equitable 
distances for both storage and instantaneous water heaters. DOE 
concludes that these changes are consistent with the industry test 
method, ANSI Z21.10.3-2015, and simply provide additional detail and 
clarification to improve the repeatability of the test. The amended 
test set-up for instantaneous water heaters and hot water supply 
boilers to be tested with a recirculating loop is shown in Figure III.4 
of this final rule.
    Further, in response to Raypak's comment regarding specifying the 
pipe length in terms of multiples of pipe diameter, DOE believes that 
given the increase in distance of the outlet water temperature sensor 
from the outlet water port adopted in this final rule, specifying 
distance in terms of pipe diameters is not necessary. In addition, DOE 
is not aware of any units for which it would not be possible to measure 
the outlet water temperature at the distance adopted in this final 
rule. Therefore, DOE has decided to maintain the required distance for 
installing the outlet water temperature sensor in terms of total piping 
length rather than pipe diameter.
    For the standby loss test, DOE believes and as noted in the 
comments, there is merit to installing the outlet water temperature 
measurement probe as close as possible to the water heater to 
accurately represent the temperature of water stored inside the heat 
exchanger during the standby loss test. Thus, DOE has decided to adopt 
separate locations for measuring outlet water temperature for the 
thermal efficiency test and standby loss test for instantaneous water 
heaters and hot water supply boilers. Specifically, for the standby 
loss test, based on the recommendations of commenters, the outlet water 
temperature sensors must be installed in the outlet water piping within 
one inch (either inside or outside) of the outlet water port. To avoid 
confusion with the outlet water temperature measured in the thermal 
efficiency test, DOE designates this temperature measurement ``heat 
exchanger outlet water temperature,'' denoted as ``TOHX.'' 
As a result, DOE has modified Figure III.1, Figure III.2, Figure III.3, 
and Figure III.4 proposed in the May 2016 NOPR by adding an extra 
temperature sensor, TOHX, at a distance of one-inch from the 
outlet port of the water heater (either inside or outside).
    With regard to Bradley's comment on including the term 
``enclosure'' with the term ``water heater jacket,'' DOE agrees that 
the suggested phrase better encompasses the range of instantaneous 
water heater designs and is adding the term to the ambient condition 
measurement location requirements adopted in this final rule for 
instantaneous water heaters.
    Figure III.1, Figure III.2, Figure III.3, and Figure III.4 (for 
units tested with a recirculating loop) of this final rule show the 
required location of the outlet water temperature measurement and the 
heat exchanger outlet water temperature measurement that DOE adopts in 
this final rule for the thermal efficiency test and standby loss test, 
respectively, for instantaneous water heaters and hot water supply 
boilers.
2. Multiple Outlet Water Connections
    In the May 2016 NOPR, DOE proposed that for instantaneous water 
heaters with multiple outlet water connections, the outlet water 
temperature be maintained at 70[emsp14][deg]F  
2[emsp14][deg]F at each outlet connection, and the average outlet 
temperature for use in the subsequent calculations be determined as the 
average of the values measured at each connection leaving the water 
heater jacket. 81 FR 28588, 28614 (May 9, 2016). In response, Bradford 
White disagreed with DOE's proposal to require measurement of the 
outlet temperature at each outlet connection, arguing that the proposed 
changes are overly burdensome due to the addition of more thermocouples 
and complex piping configurations that the proposed changes may result 
in. Bradford White stated that multiple outlets are sometimes included 
on products to accommodate different field piping configurations that 
may be encountered in replacement installations, and that not all 
connections are intended to be used in the field. (Bradford White, No. 
21 at p. 11)
    DOE clarifies that the provisions proposed for multiple outlet 
water connections were intended to apply to equipment that is designed 
to use both (or multiple) outlet water connections simultaneously 
during field operation, such as models that contain two individual 
units assembled or stacked together and are sold as a single, larger 
unit. Such units typically employ external piping to combine the 
multiple supply and outlet water connections (respectively) to form a 
single supply and single outlet water connection for the entire water 
heater. To achieve the fuel input rate for which the model is designed 
and rated, both sub-units need to be supplied with water and fired at 
their respective full firing capacities. If a model consists of 
redundant outlet water connections that can be used optionally to 
accommodate various field piping configurations, and the outlet

[[Page 79299]]

water connection does not need to be operated to achieve the rated 
input for the model, then the outlet water provisions are not required 
to be applied to such outlet water connections. Therefore, in this 
final rule, DOE retains the provisions for placement of temperature 
sensors for measuring outlet water temperatures for the thermal 
efficiency and standby loss tests for instantaneous water heaters and 
hot water supply boilers equipped with multiple outlet water 
connections, and DOE clarifies in the regulatory text that these 
requirements are only applicable if the simultaneous use of those 
outlet connections is necessary to achieve the rated input during 
testing.
    DOE also adopts changes for water heaters with multiple outlet 
water connections to reflect the changes discussed in section III.I.1 
with regard to the placement of the outlet water temperature sensors 
for the thermal efficiency and standby loss test. The outlet water 
temperature sensor placement provisions discussed in section III.I.1 
(as applicable) must be applied to all outlet water connections leaving 
the water heater that are required to be used to achieve the designed 
fuel input rate for the thermal efficiency and standby loss test.
3. Supply and Outlet Water Valves
    The current test procedure for instantaneous water heaters and hot 
water supply boilers does not clearly indicate the location and 
installation of the supply and outlet water valves. In the May 2016 
NOPR, DOE proposed to require supply and outlet water valves to be 
installed within a specified distance of the water heater. 
Specifically, for instantaneous water heaters and hot water supply 
boilers shipped without external piping installed at the point of 
manufacture, DOE proposed to require that the supply water valve be 
installed within 5 inches of the jacket, and the outlet water valve be 
installed within 10 inches of the jacket. For instantaneous water 
heaters and hot water supply boilers with external piping assembled at 
the manufacturer's premises prior to shipment, DOE proposed to require 
that the supply and outlet water valves be installed within 5 inches of 
the end of the piping shipped with the unit. 81 FR 28588, 28614 (May 9, 
2016).
    Bradford White disagreed with DOE's proposed changes, stating that 
moving the inlet and outlet water valves closer to the unit being 
tested would not provide more accurate test results. Bradford White 
also expressed concern with the depiction of the pressure relief valve 
outside the outlet water valve in DOE's proposal. (Bradford White, No. 
21 at p. 11)
    As discussed in section III.H.3, DOE received several comments from 
stakeholders on its proposal to require that testers turn off both the 
supply and outlet water valves while conducting the standby loss test 
for instantaneous water heaters and hot water supply boilers (including 
flow-activated instantaneous water heaters). In summary, after 
considering those comments DOE has decided to not adopt the proposed 
requirement to turn off the supply water valve during the standby loss 
test to address concerns expressed by stakeholders about safety and 
thermal expansion of the water inside the water heater. As a result of 
this decision, DOE will not require the supply water valve to be placed 
at a distance of 5 inches away from the water heater jacket. With 
regards to the outlet water valve, DOE believes there is merit in 
placing the valve close to the unit and turning it off during the 
standby loss test. Locating the outlet water valve close to the unit 
would prevent the outlet water from mixing with water in the downstream 
water piping and thereby reduce heat lost from mixing with water 
contained in the piping, which DOE believes will result in a more 
repeatable test since the distance of piping before the valve (and 
therefore the volume of water in the piping) would be consistent across 
tests. DOE also believes that installing the outlet water valve close 
to the unit and turning it off during test will more accurately account 
for the standby loss of the unit, as it would reduce the effect of 
piping losses during the test. Therefore, while DOE agrees with not 
requiring the supply water valve to be placed close to the unit, DOE 
has decided to adopt provisions for placing the outlet water valve 
close to the water heater. In section III.I.1of this final rule, based 
on the comments received, DOE decided to permit instantaneous water 
heaters and hot water supply boilers to be set up as per Figure III.1, 
Figure III.2, and Figure III.3 (as applicable) for conducting the 
thermal efficiency and standby loss test (see section 2.2 of Appendix C 
to Subpart G and section 2.2 of Appendix D to Subpart G). As a result 
of this amendment, the water heaters would be required to be installed 
with heat traps in the inlet and outlet water piping connected to the 
water heater. Due to the inclusion of heat traps in the outlet water 
piping, installing a valve at a distance of 10 inches from the outlet 
water connection would not be required, as the heat trap would restrict 
the convective movement of hot water from the water heater. As a 
result, DOE is requiring the installation of the outlet water valve 
downstream of the outlet water heat trap, within a distance of 10 
inches downstream from the outlet water temperature sensor placed at 
the second elbow from the water heater in the outlet water piping. 
These amendments to the location of the outlet water valve are depicted 
in the test set ups in Figure III.1, Figure III.2, Figure III.3, and 
Figure III.4 of this final rule.
    To address Bradford White's concern regarding the pressure relief 
valve being installed downstream from the outlet water valve, DOE is 
adding provisions in the test procedure that the pressure relief valve 
must be installed between the outlet water valve and the water heater. 
Figure III.4 of this final rule that shows the set-up for testing 
instantaneous water heaters and hot water supply boilers depicts the 
pressure relief valve between the outlet water valve and the water 
heater being tested.
4. Additional Comments
    In addition to comments related to the test set-up, DOE also 
received comments about measuring the gas line temperature as indicated 
by temperature probe T4 in Figure III.4 of the May 2016 NOPR 
for instantaneous water heaters and hot water supply boilers. DOE 
received comments from Raypak and Rheem stating that the T4 
is generally part of the gas meter or otherwise must be measured at the 
gas meter and not elsewhere in the gas line. (Raypak, No. 28 at p. 3; 
Rheem, No. 34 at p. 17) Raypak commented that most of the thermocouples 
used to measure the temperature in the gas line are actually mounted in 
the gas meter and recommended indicating the location of the 
temperature sensor in the gas meter itself, located in the gas 
connection in Figure III.4 in the May 2016 NOPR. (Public Meeting 
Transcript, No. 20 at p. 88)
    DOE agrees with the comments on the gas temperature measurement and 
has modified the test set-up to have the gas temperature measured at 
the gas meter. DOE concludes that this clarification is consistent with 
ANSI Z21.10.3-2015.
    Rheem sought clarification on using a radiation shield for 
temperature probes. (Rheem, No. 34 at p. 17) A radiation shield is 
generally applied on a temperature probe to prevent potential radiative 
heat transfer from the hot surfaces that are close to or in direct 
contact with the burner flame to the temperature probe. If a probe is 
located in the vicinity of a surface at a very high temperature, then 
there could be some

[[Page 79300]]

heat transferred from the hot surface to the temperature probe in the 
form of radiation. This would lead to an inaccurate representation of 
the temperature that the probe is intended to measure. Therefore, in 
experimental tests, it is typical to use a radiation shield to protect 
against unwanted radiation and to provide a more accurate measurement 
of the temperature that is intended to be measured. DOE's current test 
procedure requires using a radiation shield for temperature sensors 
used to measure the ambient temperature. In this final rule, DOE is 
also adopting the use of radiation shield(s) to measure the test air 
temperature. DOE concludes that these changes are consistent with ANSI 
Z21.10.3-2015.
5. Test Set-Up for Instantaneous Water Heaters and Hot Water Supply 
Boilers
    As initially discussed in section III.I.1, AHRI recommended that 
DOE require an instantaneous water heater to be tested using the test 
set-up in Figures 1, 2, and 3 proposed for storage water heaters in the 
May 2016 NOPR (see 81 FR 28588, 28599-28600). (AHRI, No. 26 at p. 10)
    After considering this and all of the other comments related to the 
test set-up for instantaneous water heaters and hot water supply 
boilers, DOE has decided to allow the use of the same piping 
configuration adopted for storage water heaters to be used for testing 
instantaneous water heaters and hot water supply boilers that do not 
require a recirculating loop. As a result, the piping arrangements in 
Figure III.1, Figure III.2, and Figure III.3 adopted in this final rule 
(see section III.C) are also applicable to instantaneous water heaters 
and hot water supply boilers that do not require a recirculating loop 
for testing. Although the same piping arrangements are being adopted 
for instantaneous water heaters and hot water supply boilers, there are 
some variations in the setup needed to accommodate testing of 
instantaneous water heaters and hot water supply boilers. Specifically, 
instantaneous water heaters and hot water supply boilers require the 
addition of an outlet water valve and the inclusion of an additional 
temperature sensor to measure the heat exchanger outlet water 
temperature. Figure III.1, Figure III.2, and Figure III.3 show the test 
setup for gas-fired and oil-fired storage water heaters and storage-
type instantaneous water heaters, and are generally applicable to 
electric storage and storage-type instantaneous water heaters and to 
instantaneous water heaters and hot water supply boilers (that are not 
tested with a recirculating loop), with the exceptions that an outlet 
water valve and heat exchanger outlet temperature sensor are present. 
In this final rule, for clarity, DOE is adopting separate figures 
within each appendix, with the slight variations to outlet valve and 
temperature sensors discussed herein.
    In addition, for instantaneous water heaters and hot water supply 
boilers, DOE is adopting Figure III.4, which must be used for the 
installation of the recirculating loop to conduct the thermal 
efficiency and standby loss test (as applicable).
[GRAPHIC] [TIFF OMITTED] TR10NO16.007


[[Page 79301]]



J. Test Procedure for Rating Commercial Heat Pump Water Heaters

    In the May 2016 NOPR, DOE proposed definitions and test procedures 
for CHPWHs. 81 FR 28588, 28617-28622 (May 9, 2016). The comments 
received on DOE's proposals for CHPWH are discussed in the following 
sections.
1. Definitions of CHPWH
    In the May 2016 NOPR, DOE proposed a definition for ``commercial 
heat pump water heater'' and associated definitions for ``air-source 
commercial heat pump water heater,'' ``direct geo-exchange commercial 
heat pump water heater,'' ``ground water-source commercial heat pump 
water heater,'' and ``indoor water-source commercial heat pump water 
heater.'' 81 FR 28588, 28617-28619 (May 9, 2016).
    In response, CA IOUs, Bradford White, NEEA, and EEI expressed 
support for the proposed definition of CHPWH. (CA IOUs, No. 23 at p. 2; 
Bradford White, No. 21 at p. 11; NEEA, No. 30 at p. 1; and EEI, No. 29 
at p. 3) CA IOUs added that the proposed definition of CHPWH accurately 
categorizes the equipment and is similar to the definition used by AHRI 
in AHRI Standard 1300, ``2013 Standard for Performance Rating of 
Commercial Heat Pump Water Heaters'' (AHRI 1300-2013), and that the 
definitions for proposed categories for CHPWH add more clarity. (CA 
IOUs, No. 23 at p. 2)
    DOE also received comments recommending several modifications to 
the definitions related to CHPWH. AHRI stated that the proposed 
definitions for CHPWH, air-source CHPWH, direct geo-exchange CHPWH, and 
water-source CHPWH are inconsistent with the definitions in AHRI 1300-
2013 and ASHRAE 118.1, because the proposed definition for CHPWH does 
not include ancillary equipment and the proposed 12 kW threshold 
excludes CHPWH units that are intended to deliver hot water above 
180[emsp14][deg]F, but have lower inputs. Further, AHRI argued that DOE 
has: (1) Added language for defining direct geo-exchange CHPWH; (2) 
split the water-source CHPWH definition into two parts (i.e., ground 
water and indoor water); and (3) changed ``indoor or outdoor air'' to 
``surrounding air'' for air-source CHPWH. Finally, AHRI stated that the 
definitions in AHRI 1300 and ASHRAE 118.1 were developed through 
consultations with industry experts and stakeholders; AHRI recommended 
maintaining consistency with the industry test standards. (AHRI, No. 26 
at p. 14) Rheem commented that 12 kW threshold for commercial 
classification of heat pump water heaters does not adequately identify 
the source of the power input and does not account for total power 
consumption for hybrid heating technology used exclusively or in 
conjunction with electric resistive heating elements. Rheem stated that 
the 12 kW threshold is a good indicator for power consumption by 
electric resistance water heaters but is not applicable to models that 
use only heat pump technology and argued that the physical size of a 
compressor to with 12 kW of input power to heat the water would be too 
large and physically impossible to fit in the current CHPWH systems. 
Rheem recommended that a water heater with heat pump technology be 
classified as commercial equipment if the compressor uses between 7 and 
10 amps of electric current or more than 12 kW of input power for 
electric resistance heating. Rheem also commented on the proposed 
definition of air-source CHPWH, suggesting that it does not 
differentiate between the sources of surrounding air and does not 
account for ducted air flow. (Rheem, No. 34 at p. 18) The Joint 
Advocates stated that the definition of ground-water source CHPWH is 
potentially confusing and inconsistent with the nomenclature used in 
the ground-source heat pump industry. According to the Joint Advocates, 
the definition of ground-source CHPWHs is commonly understood to 
include both direct geo-exchange and ground water-source CHPWHs. The 
Joint Advocates recommended that DOE either adopt definitions listed in 
ASHRAE's Geothermal Heating and Cooling: Design of Ground-Source Heat 
Pump Systems (GSHP) \16\, or divide ground-source CHPWH into three sub-
categories: (1) Closed-loop systems that extract heat from the ground 
by circulating water or anti-freeze; (2) open-loop systems that extract 
heat from water pumped from a well or surface pond; and (3) direct 
expansion systems that circulate refrigerant in closed-loops to extract 
heat directly from the ground. (Joint Advocates, No. 32, at p. 3) 
Earthlinked Technologies also questioned why ground-source closed-loop 
CHPWHs (which use the test procedure for water-source CHPWH, but are 
rated to a different evaporator entering water temperature in ASHRAE 
118.1-2012) are not included in DOE's categorizations of CHPWH. 
(Earthlinked, No. 37 at p. 3) Earthlinked Technologies also suggested 
modifying the proposed definition for CHPWH to include additional 
provisions for the type of power supplied to the unit. Specifically, 
the commenters suggest that proposed definition must encompass all 
units with minimum 12 kW power supply (which is included in the 
proposed definition) and a minimum rated current condition of >24 A 
with single phase power supply; a maximum voltage condition of not 
greater than 250V; and all units with three phase power supply as rated 
input. (Earthlinked, No. 37 at pp. 1-2)
---------------------------------------------------------------------------

    \16\ ASHRAE's Geothermal Heating and Cooling: Design of Ground-
Source Heat Pump Systems, can be purchased from: https://www.ashrae.org/resources--publications/bookstore/geothermal-heating-and-cooling-design-of-ground-source-heat-pump-systems.
---------------------------------------------------------------------------

    DOE's proposed definition for CHPWH includes the term ``low 
temperature heat source,'' and EEI suggested modifying the word ``low'' 
to ``lower'' and further recommended that, when DOE decides to 
prescribe energy conservation standards for CHPWHs, the standards 
should be different from those prescribed for commercial electric 
resistance storage water heaters and commercial electric resistance 
instantaneous water heaters. (EEI, No. 29 at p. 3) NEEA recommended 
expanding the definition of CHPWH to include gas absorption heat pump 
water heaters. (NEEA, No. 20 at p. 2)
    DOE reviewed all comments received in response to this issue and, 
after careful consideration, is adopting the definitions for direct 
geo-exchange CHPWH, ground water-source CHPWH, and indoor water-source 
CHPWH as proposed in the May 2016 NOPR. For the definition for CHPWH, 
DOE is incorporating additional language regarding ``ancillary 
equipment'' as suggested by AHRI, so as to make the definition 
consistent with the definition of that term in ASHRAE 118.1-2012. For 
similar reasons, for air-source CHPWH, DOE replaces ``surrounding air'' 
with ``indoor or outdoor air.'' DOE believes that the definitions of 
CHPWH and its categories sufficiently represent the kinds of CHPWH 
available on the market. DOE considered NEEA's suggestion to expand the 
definitions to include those CHPWH with gas absorption technology, but 
has not identified any equipment commercially available on the market 
that utilizes gas-fired absorption technology for heating potable 
water. Therefore, in this final rule, the definitions are limited to 
include electrically operated heat pump technology.
    With regard to the threshold for commercial equipment, DOE notes 
that EPCA classifies electric water heaters with less than 12 kW rated 
electrical input as consumer water heaters (42 U.S.C. 6291(27)), and 
that a heat pump water heater with a rated input of less than 12 kW 
would, therefore, be a

[[Page 79302]]

consumer water heater. The 12 kW limitation refers to the total 
electrical power input to the heat pump water heater which could either 
be only the input to the heat pump if no backup electric resistance 
elements are present, or a combination of heat pump technology and 
electric resistance elements. DOE does not agree with Rheem and 
Earthlinked Technologies' comments on adopting additional power supply 
specifications (such as electrical current range for the compressor or 
voltage and phase requirements) to differentiate commercial heat pump 
water heaters from residential heat pump water heaters. The suggested 
range of 7 to 10 amps in Rheem's comments could result in a heat pump 
water heater with less than 12 kW being classified as commercial 
equipment, which would be contrary to EPCA's definitions. Thus, the 
most appropriate parameter that accounts for both the electric current 
and voltage in a single term is the electrical power input.
    Regarding comments from the Joint Advocates and Earthlinked 
Technologies on ground-source closed-loop CHPWH, DOE agrees that such 
systems are a category of water-source CHPWH that are different from 
ground water-source CHPWH in the manner that they extract heat from the 
earth. As the name indicates, a ground-source closed-loop CHPWH uses a 
closed water loop to extract heat from the earth and transfer it to the 
CHPWH unit. This is different from a ground water-source CHPWH that 
uses an open water loop system, where the unit pulls in water from a 
lake or a pond and uses it as a heat source. Considering the 
differences between the CHPWH systems, DOE agrees that ground-source 
closed-loop CHPWH must be rated at conditions different from both, 
ground and indoor water-source CHPWHs.\17\ Therefore, in this final 
rule, DOE adopts separate rating conditions and definitions for ground-
source closed-loop CHPWHs as sub-categories of water-source CHPWHs. DOE 
disagrees with comments from Joint Advocates of combining the ground-
source closed-loop CHPWH, ground water-source CHPWH and direct geo-
exchange CHPWH into a single category. DOE notes that ground-source 
closed-loop CHPWH and ground water-source CHPWH, both use water as a 
medium to extract heat from the ground or a water body. Direct-geo-
exchange CHPWHs, extract heat directly from the earth from refrigerant 
tubing, which is embedded inside the ground. Therefore, ground water-
source CHPWH and ground-source closed-loop CHPWH must be grouped 
together under water-source CHPWH, while direct-geo-exchange CHPWH must 
be under a separate category. These definitions and categories are same 
as those in ASHRAE 118.1-2012, align with DOE's categorization of test 
procedures adopted in this final rule, and are consistent with the 
industry test standards. Combining the ground water-source CHPWH and 
direct geo-exchange into one category, as suggested by the Joint 
Advocates, may result in confusion as to the applicable rating 
conditions and corresponding test procedure. Therefore, DOE is 
retaining this aspect of the proposed definitions.
---------------------------------------------------------------------------

    \17\ For more information on ground-source closed-loop CHPWH and 
ground water-source CHPWH, see http://energy.gov/energysaver/geothermal-heat-pumps.
---------------------------------------------------------------------------

    In response to AHRI's comment that DOE has added language for 
defining direct geo-exchange CHPWH, DOE notes that AHRI 1300-2013 
defines a direct geo-exchange commercial heat pump water heater as a 
commercial heat pump water heater ``that utilizes the earth as the heat 
source,'' while DOE's proposed definition in the May 2016 NOPR defines 
the term as a commercial heat pump water heater ``that utilizes the 
earth as a heat source and allows for direct exchange of heat between 
the earth and the refrigerant in the evaporator coils.'' DOE believes 
that the additional language further clarifies the types of models that 
qualify as direct geo-exchange commercial heat pump water heaters. The 
definition adopted for CHPWH and associated definitions for the kinds 
of CHPWH are contained in the regulatory text at the end of this final 
rule.
2. Test Procedure for CHPWH
    In the May 2016 NOPR, DOE proposed a test method for CHPWH that 
would incorporate by reference an industry test method, ASHRAE 118.1-
2012, but with modifications to adopt rating conditions in another 
industry test method, AHRI 1300-2013. (Note, that AHRI 1300-2013 
references ASHRAE 118.1-2012 for specifying the actual conduct of the 
test, but specifies different rating conditions than those specified by 
ASHRAE 118.1-2012.) 81 FR 28588, 28617-28622 (May 9, 2016). In this 
final rule DOE is incorporating by reference certain sections, figures, 
and tables from ASHRAE 118.1-2012 in its test procedure for CHPWHs, as 
discussed in the following sections.
    ASHRAE 118.1-2012 classifies CHPWHs into two types, with a separate 
test method for each: (1) ``Type IV''--equipment that can be operated 
without requiring a connection to a storage tank; and (2) ``Type V''--
equipment that includes an integral storage tank or requires connection 
to a storage tank for operation. The test procedure in ASHRAE 118.1-
2012 for Type V equipment requires units to be connected to a tank that 
is either supplied by the manufacturer along with the unit or is 
specified by the manufacturer, while the test procedure in ASHRAE 
118.1-2012 for Type IV equipment does not require connection to a tank. 
After reviewing product literature, DOE noted that most of CHPWH 
available on the market are Type V equipment in that they require 
connection to a storage tank for operation. However, manufacturers of 
such CHPWH typically neither supply nor specify a storage tank 
appropriate for that equipment. ASHRAE 118.1-2012 does not include a 
test method for Type V units for which an appropriate tank is neither 
supplied nor specified by the manufacturer. After considering several 
options, DOE ultimately proposed in the May 2016 NOPR to utilize a 
method similar to the test method for Type IV equipment for all CHPWH. 
81 FR 28617-28622 (May 9, 2016). As noted above, DOE also proposed to 
use the rating conditions specified by AHRI 1300-2013. AHRI 1300-2013 
contains multiple rating conditions, so DOE selected those it believed 
to be most representative of conditions encountered in the field during 
actual use. In addition, DOE also received comments from AHRI 
recommending a specific set of rating conditions that are also listed 
in AHRI 1300-2013. In reviewing the market, DOE noted that some CHPWH 
are capable of achieving various temperature rises based on the 
intended application. As a result, DOE proposed that air-source CHPWH 
be tested with a supply water temperature of 70[emsp14][deg]F and, if 
the tested model is unable to achieve the required outlet water 
temperature condition, that the supply water temperature be changed to 
110[emsp14][deg]F.
    Rheem commented that ASHRAE 118.1-2012 is sufficient as a testing 
standard to represent the performance of CHPWH and recommended adopting 
the testing standard in full. Rheem also stated that DOE's proposed 
deviations and additions to ASHRAE 118.1-2012 are too burdensome to 
implement, and that the only exception to the ASHRAE 118.1-2012 testing 
standard that it supports is to specify the requirements in AHRI 1300-
2013 for CHPWH that can operate with multiple voltages. AHRI 1300-2013 
requires such units to be tested at the lowest voltage specified on the 
nameplate and specifies that, at the manufacturer's option, the test 
may be

[[Page 79303]]

repeated at a higher voltage. (Rheem, No. 34 at pp. 18-19)
    AHRI recommended that the entering water temperature for air-source 
CHPWH be maintained at 110[emsp14][deg]F to remain consistent with all 
other categories of CHPWH and allow a basis for comparison of different 
categories of CHPWH. AHRI argued that the NOPR acknowledges that a test 
conducted with an inlet water temperature of 70[emsp14][deg]F and 
110[emsp14][deg]F will provide the same results. (AHRI, No. 26 at p. 
12) CA IOUs also argued against adopting two inlet water temperatures 
for air-source CHPWHs, stating that having two temperatures would 
result in some equipment with a lower efficiency being tested to a less 
stringent rating condition. (CA IOUs, No. 23 at p. 4) Earthlinked 
Technologies also commented on this issue stating that rating certain 
air-source CHPWHs with an entering water temperature of 
70[emsp14][deg]F while testing all other CHPWHs (including CHPWHs that 
are not air-source) with an entering water temperature of 
110[emsp14][deg]F would not provide a fair comparison between products 
and prevent contractors from helping customers make informed decisions. 
The commenters suggest using 110[emsp14][deg]F as the single entering 
water temperature rating condition for all CHPWH equipment, which is 
also in line with the AHRI-recommended rating conditions. (Earthlinked, 
No. 37 at p. 2)
    The Joint Advocates questioned whether requiring testing without a 
specified storage tank would create an inherent disadvantage for self-
contained units with integrated tanks. The Joint Advocates recommended 
that instead, DOE should require the CHPWH to be paired with a storage 
tank with a volume proportional to the steady-state heating output of 
the CHPWH. The Joint Advocates stated that this would ensure 
consistency between CHPWH with integrated and non-integrated storage 
tanks. (Joint Advocates, No. 32 at p. 3) NEEA commented that DOE 
proposed separate test procedures for air, water, and direct geo-
exchange CHPWH but did not specify a test procedure or test conditions 
for self-contained versus remote air condensers. (NEEA, No. 30 at p. 2) 
EEI agreed with the use of ASHRAE 118.1-2012, which was developed 
through ASHRAE's standards development processes which uses a consensus 
based approach. (EEI, No. 29 at p. 3) CA IOUs commented in support of 
establishing separate test procedures for different categories of CHPWH 
based on ASHRAE 118.1-2012 and AHRI 1300-2013. With regard to the 
rating conditions for air-source CHPWH, CA IOUs stated that the rating 
condition of 80.6[emsp14][deg]F dry-bulb temperature and 
71.2[emsp14][deg]F wet-bulb temperature may be too warm for CHPWH, and 
recommended using a temperature that is higher than 50[emsp14][deg]F 
dry-bulb temperature and 44.3[emsp14][deg]F wet-bulb temperature, but 
lower than the proposed rating condition. CA IOUs also recommended 
reviewing the study titled, West Village Community: Quality Management 
Processes and Preliminary Heat Pump Water Heater Performance, completed 
by Davis Energy Group for NREL as a starting point to establish rating 
conditions.\18\ (CA IOUs, No. 23 at p. 3)
---------------------------------------------------------------------------

    \18\ http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/west_village_hpwh.pdf.
---------------------------------------------------------------------------

    In response to these comments, DOE notes that the test procedure 
proposed for air-source CHPWH is based on investigative testing that 
was carried out as part of the preparation of the May 2016 NOPR, the 
results of which are discussed in extensive detail in that document. 
Based on the test results, DOE noticed that several CHPWH models may be 
designed to achieve a lower temperature rise (from 110[emsp14][deg]F 
supply water temperature to 120[emsp14][deg]F outlet water 
temperature), while some models may be able to achieve a higher 
temperature rise (from 70[emsp14][deg]F supply water temperature to 
120[emsp14][deg]F outlet water temperature), depending on the intended 
application. If DOE were to adopt a supply water temperature of 
110[emsp14][deg]F for all air-source CHPWH, then there would be some 
air-source CHPWH units on the market that would not be able to achieve 
the required outlet water temperature condition (120[emsp14][deg]F 
 5[emsp14][deg]F), as DOE observed during its investigative 
testing. By allowing different supply water temperature conditions 
based on the capabilities of a CHPWH, the test procedure will be 
capable of testing all kinds of air-source CHPWH units currently 
available on the market. Therefore, in this final rule, DOE retains the 
additional proposed provisions for air-source CHPWH, i.e., to require 
units to be tested with a supply water temperature of 70[emsp14][deg]F, 
and use supply water at 110[emsp14][deg]F only if the unit is unable to 
meet the required outlet water temperature conditions at 
70[emsp14][deg]F.
    In response to the comments on the evaporator entering air rating 
conditions being too high for CHPWH, DOE notes that these conditions 
are included in the industry-accepted test standard AHRI 1300-2013, and 
are also similar to the rating conditions specified in another 
industry-accepted testing standard, ASHRAE 118.1-2012 (80[emsp14][deg]F 
dry-bulb temperature and 67[emsp14][deg]F wet-bulb temperature). In 
addition, DOE conducted tests using the proposed evaporator entering 
air rating conditions and found that all the tested air-source CHPWH 
units were able to operate under these ambient conditions. DOE explored 
lower entering air temperatures and discovered that certain CHPWH 
models do not operate at low ambient temperatures, and would not 
operate at lower entering air temperatures. Therefore, in order to have 
a test method that is both representative and that can be used for all 
types of CHPWH currently on the market, DOE is adopting the rating 
conditions for evaporator entering air temperature that were proposed 
in the May 2016 NOPR.
    DOE also considered comments received from the Joint Advocates 
about the comparison of CHPWH models with and without an integral 
storage tank, and whether requiring testing without requiring a storage 
tank would be a disadvantage for CHPWH units that are equipped with an 
integral storage tank. As discussed in the May 2016 NOPR, DOE proposed 
that CHPWHs that are intended to be operated in-field with a separately 
attached storage tank must be tested using a test procedure similar to 
that prescribed for Type IV equipment in ASHRAE 118.1-2012, which does 
not require a storage tank. DOE generally agrees that COPh 
ratings of two CHPWH units, one equipped with an integral storage tank 
and the other not equipped with an integral storage tank, both tested 
using DOE's proposed test procedure, may be different from each other. 
DOE does not see this difference as an advantage of one unit over the 
other because of the test procedure, but rather as a fundamental 
difference between the designs and operational characteristics of 
different CHPWH units. Further, DOE noted in the May 2016 NOPR that 
adding a separate storage tank to test a Type IV CHPWH would be an 
incorrect representation of the efficiency ratings of the unit itself 
and would include the losses in the external tank. For CHPWHs equipped 
with a storage tank, the tank is an integral component of the CHPWH as 
packaged and shipped by the manufacturer. Therefore, any losses in 
performance due to the inclusion of the tank must be included as part 
of the efficiency ratings of such CHPWHs. DOE is not aware of any 
commercial heat pump water heaters with an integrated storage tank 
currently available on the market. In addition, DOE still has concerns 
regarding specifying the characteristics of the storage tank with which 
the CHPWH would be tested. The Joint Advocates suggest pairing CHPWH 
with a storage tank with a volume proportional to the

[[Page 79304]]

steady-state heating output of the CHPWH, but this does not address the 
other characteristics of the tank that can affect efficiency and 
operation, such as the insulation thickness, number of ports, and tank 
aspect ratio. Based on the foregoing, DOE has decided to continue to 
require testing without attaching an external tank for CHPWHs that are 
not integrated with a storage tank. For CHPWH models equipped with an 
integral storage tank, DOE adds clarifying provisions to the test 
procedure for CHPWHs proposed in the May 2016 NOPR, which is based on 
the test procedure in ASHRAE 118.1-2012 for Type IV equipment. These 
added provisions incorporate by reference certain sections applicable 
to the test procedure for Type V equipment in ASHRAE 118.1-2012. DOE is 
adding these provisions to better represent the field energy use and 
installation requirements for CHPWHs equipped with an integral storage 
tank. Specifically, in addition to the sections included in DOE's 
proposed test procedure, DOE has decided to incorporate by reference 
sections 7.3.1 (pertaining to setting up of temperature sensors inside 
the tank), 7.7.8 (pertaining to input requirements of water-heating 
mode test), and 8.7.1 (pertaining to setting the storage tank 
thermostats) of ASHRAE 118.1-2012, with the exception that the 
provisions will only apply to Type V equipment that is equipped with an 
integral storage tank. Further, DOE has also decided to incorporate by 
reference Figures 6, 7, and 8, which pertain to the test set-up of Type 
V equipment in ASHRAE 118.1-2012.
    As suggested by Rheem, DOE considered adopting the provision in 
AHRI 1300-2013 for CHPWHs that are capable of operating at multiple 
voltages, which is not included in ASHRAE 118.1-2012. DOE agrees with 
the comment and has decided to include provisions that require CHPWHs 
that can operate at multiple voltages to be tested and rated at the 
lowest rated voltage. The test procedure adopted for CHPWH in this 
final rule is included in appendix E to subpart G of part 431 in the 
regulatory text.
    Finally, in response to Rheem's assertion that the deviations and 
additions to ASHRAE 118.1-2012 proposed in the May 2016 NOPR are too 
burdensome to implement, DOE notes that the procedures adopted by this 
final rule incorporate by reference various sections of ASHRAE 118.1-
2012 and are largely based on that procedure. Thus, DOE does not 
believe that the test method adopted in this final rule is 
significantly more burdensome than ASHRAE 118.1-2012, which Rheem 
recommended that DOE adopt.
    As discussed in section III.J.1, DOE is adopting separate 
definitions for ground-source closed-loop CHPWHs. In light of these 
changes, DOE also adds separate rating conditions for ground-source 
closed-loop CHPWH, which are the same as those specified in Table B-3 
of ASHRAE 118.1-2012 and require an evaporator entering water 
temperature of 32[emsp14][deg]F. To achieve sub-freezing temperatures 
required for such units, DOE also adds requirements that the evaporator 
entering water be mixed with 15-percent methanol by-weight. The test 
procedure used to rate such units is the same test procedure adopted in 
this final rule for water-source CHPWHs. The rating condition for 
condenser water supply temperature in maintained 110[emsp14][deg]F, 
which is the same for all other water-source CHPWH units.

K. Gas Pressure

    In the May 2016 NOPR, DOE included proposed requirements for gas 
pressure in its proposed test procedures for gas-fired and oil-fired 
CWH equipment. 81 FR 28588, 28641, 28646, 28651 (May 9, 2016). In its 
proposal, DOE included requirements that the outlet pressure of the gas 
appliance regulator be within the range specified by the manufacturer. 
In response to the May 2016 NOPR, Bradford White and AHRI commented 
that the proposed term ``outlet pressure'' should be changed to ``gas 
supply pressure'' because manufacturers specify a range for gas supply 
pressure, but only a single value for gas outlet pressure. (Bradford 
White, No. 21 at p. 21; AHRI, No. 26 at p. 6)
    DOE acknowledges that manufacturers specify a range for gas supply 
pressure and a single value for gas outlet pressure, as required for 
certification to ANSI Z21.10.3-2015. Therefore, in this final rule, DOE 
is adopting requirements regarding both gas supply pressure and gas 
outlet pressure for gas-fired CWH equipment. First, DOE is requiring 
that gas supply pressure must be within the range specified by the 
manufacturer. This requirement was suggested by Bradford White and 
AHRI, and is consistent with the requirements for nameplate ratings 
included in ANSI Z21.10.3-2015. Regarding gas outlet pressure, after an 
assessment of manufacturer literature for models currently on the 
market, DOE notes that the gas outlet pressure specified by the 
manufacturer is often a very low value (e.g., 0.0 inches water column 
(in. w.c.) or 0.05 in. w.c.) for models that include a premix burner. 
DOE believes that achieving and measuring a gas pressure value within 
 10 percent of such a low value would be difficult given 
the typical accuracy of gas pressure measurement devices (i.e., the 
accuracy for gas pressure measurement included in ASHRAE 118.1-2012 is 
 0.1 in. w.c.). Therefore, DOE will also require that the 
difference between the outlet pressure of the gas appliance pressure 
regulator and the value specified by the manufacturer on the nameplate 
of the unit being tested must not exceed the greater of:  
10 percent of the nameplate value or  0.2 in. w.c.
    DOE is adopting a gas outlet pressure requirement to maintain 
consistency with ANSI Z21.10.3 (both the 2011 version that is currently 
incorporated by reference and the 2015 version that is being 
incorporated by reference by this final rule), and, therefore, DOE's 
existing test procedure. While a provision for an absolute tolerance 
(i.e.,  0.2 in. w.c.) is not included in ANSI Z21.10.3-
2015, DOE believes that this tolerance is warranted given that many 
units on the market have low rated gas outlet pressure values. DOE 
notes that the addition of this absolute tolerance renders this gas 
outlet pressure requirement more lenient than the requirement included 
in both DOE's current test procedure and ANSI Z21.10.3-2015; therefore, 
this adopted requirement for gas outlet pressure will not result in any 
additional test burden for manufacturers.

L. Fuel Input Rate

    In DOE's existing regulations, equipment classes and the standards 
that apply to them are determined, in part, by the input capacity of 
the CWH equipment. However, several terms are used in the existing DOE 
test procedures and energy conservation standards to describe the input 
capacity of the CWH equipment, each of which is derived from the 
maximum rated fuel input rate of the CWH equipment. To standardize 
terminology throughout its regulations for CWH equipment, in the May 
2016 NOPR, DOE proposed to define the term ``fuel input rate'' as the 
maximum rate at which gas-fired or oil-fired CWH equipment consumes 
energy during a given test, and to use the term ``fuel input rate'' in 
its test procedures for CWH equipment. 81 FR 28588, 28622 (May 9, 
2016).
1. Certification Provisions
    DOE proposed using the term ``fuel input rate'' in the division of 
equipment classes and proposed applicable testing provisions to 
determine the fuel input rate. DOE's proposal would have required 
manufacturers to measure the fuel input rate during certification

[[Page 79305]]

testing and use the mean of the measured values, after applying the 
applicable rounding provisions, in certification reports pursuant to 10 
CFR 429.44(c)(2).
    DOE also proposed including equations for determining the fuel 
input rate in its test procedures for gas-fired and oil-fired CWH 
equipment. DOE proposed including Equations C2 and C3 from section 
C7.2.3 of AHRI 1500-2015 in its test procedures for calculation of fuel 
input rate for gas-fired and oil-fired CWH equipment, respectively. DOE 
also proposed that the fuel input rate be determined by measuring fuel 
consumption at 3 consecutive 10-minute intervals during the 30-minute 
thermal efficiency test. The overall fuel input rate for the thermal 
efficiency test would be calculated using the fuel consumption over the 
entire 30-minute test. DOE proposed that during the thermal efficiency 
test, the measured fuel input rate must not vary by more than  2 percent between 10-minute interval readings.
    CA IOUs agreed with DOE's proposed definitions and provisions 
regarding fuel input rate. (CA IOUs, No. 23 at p. 2) However, several 
commenters disagreed with DOE's proposal that the certified fuel input 
rate be based on the mean of measured values obtained during efficiency 
testing. (Bock, No. 19 at p. 2; Bradford White, No. 21 at p. 12; AHRI, 
No. 26 at pp. 1-3; A. O. Smith, No. 27 at pp. 9-10; Raypak, No. 28 at 
pp. 4-5; Rinnai, No. 31 at p. 2; Rheem, No. 34 at pp. 12-13) Instead, 
these commenters suggested that the certified input rate should be a 
fixed value rather than a value that could vary from test to test and 
that the input rate is determined as part of the model's safety 
certification testing. Bradford White, AHRI, and A. O. Smith further 
stated that there is no confusion in the industry regarding fuel input 
rate terminology and that DOE's proposed fuel input rate regulations 
would harm the industry. (Bradford White, No. 21 at p. 9; AHRI, No. 26 
at p. 2; A. O. Smith, No. 27 at p. 10) AHRI stated that DOE's proposal 
would mean that every unit of a model would have a unique input rating, 
and that a model would no longer have a single input rating. (AHRI, No. 
26 at p. 2) AHRI and Rheem further argued that DOE's proposal would 
create a distinction without a difference--comparable models capable of 
meeting the same design load would be rated with slightly different 
input rates. (AHRI, No. 26 at p. 3; Rheem, No. 34 at pp. 12-13)
    AHRI and A. O. Smith stated that the maximum input rate is 
determined as part of the safety certification process, that this 
process occurs before efficiency testing, and that the safety 
certification agency requires that the maximum input capacity be 
certified as the rated input on the nameplate. AHRI and A. O. Smith 
stated that a manufacturer's first requirement is to design a model 
that will comply with all the safety standards and codes applicable to 
that model, and that part of this design phase is establishing the 
maximum input rate of the water heater. AHRI and A. O. Smith further 
argued that manufacturers do not conduct efficiency tests until they 
are certain of the model's compliance with the applicable safety 
requirements and, therefore, cannot wait until efficiency tests are 
conducted to determine the rated input. AHRI and A. O. Smith also 
commented that DOE's proposal would create an illogical situation where 
the manufacturer does not know what test to conduct based on its 
equipment class until after the test is conducted. (AHRI, No. 26 at pp. 
1-3; A. O. Smith, No. 27 at p. 10)
    Bradford White, AHRI, and A. O. Smith noted that there are several 
factors that affect the firing rate of a unit during a test, including 
the fuel higher heating value. (Bradford White, No. 21 at p. 12; AHRI, 
No. 26 at p. 2; A. O. Smith, No. 27 at p. 9) AHRI and A. O. Smith added 
that the actual higher heating value of gas delivered during testing 
may vary by  7 percent around the nominal value for natural 
gas, and that manufacturers must design products that have flexibility 
to safely use fuels with various energy densities. (AHRI, No. 26 at p. 
2; A. O. Smith, No. 27 at p. 9) Bradford White further noted that 
barometric pressure, gas meter temperature, and gas meter pressure can 
also affect the measured fuel input rate during a given test. (Bradford 
White, No. 21 at p. 12)
    AHRI commented that determination of fuel input rate during the 
thermal efficiency test is unnecessary. (AHRI, No. 26 at p. 10) AHRI 
and A. O. Smith stated that the rate at which fuel is consumed does not 
matter, and that measurement of fuel consumed and amount of energy 
delivered as heated water would reflect any variation in input rate 
during the test. (AHRI, No. 26 at p. 10; A. O. Smith, No. 27 at p. 9)
    In light of comments received, DOE is not adopting its proposed 
certification provisions for the fuel input rate. DOE believes the 
safety certification process during the design and development of CWH 
equipment models is sufficient for determining the rated input for CWH 
equipment. Safety certification through industry test standards, such 
as ANSI Z21.10.3-2015, typically requires that manufacturers use the 
rated input for the basic model as determined through the safety 
certification process, which results in the maximum rated input listed 
on the nameplate and in manufacturer literature for the basic model. 
DOE is adopting the term ``rated input'' to mean the maximum rate CWH 
equipment is rated to use energy as specified on the nameplate, and is 
adopting the term ``fuel input rate'' to mean the rate at which any 
particular unit of CWH equipment consumes energy during testing.
    However, DOE disagrees with AHRI and A. O. Smith that variation in 
fuel input rate during the test does not affect results. The thermal 
efficiency test is a steady-state test, and, consequently, all 
parameters that affect efficiency should be held constant throughout 
the test. Therefore, DOE is adopting its proposed requirement that the 
fuel input rate be determined by measuring fuel consumption at 
consecutive 10-minute intervals during the 30-minute steady-state 
verification period and the 30-minute thermal efficiency test. DOE's 
adopted provisions regarding the steady-state verification period and 
associated requirements for establishing steady-state operation are 
discussed in section III.F.1 of this final rule. The overall fuel input 
rate for the thermal efficiency test will be calculated using the fuel 
consumption over the entire 30-minute test, and must be within  2 percent of the rated input certified by the manufacturer. 
During the thermal efficiency test and the 30-minute steady-state 
verification period, the measured fuel input rates for these 10-minute 
periods must not vary by more than  2 percent between any 
two readings. As discussed in section III.F.1 of this final rule, DOE 
does not expect its requirements for measuring fuel input rate during 
the steady-state verification period and thermal efficiency test to 
impose a significant burden on manufacturers.
    DOE is adopting the equations for calculation of fuel input rate 
that were proposed in the May 2016 NOPR and are based on equations 
included in AHRI 1500-2015 for testing of commercial packaged boilers. 
DOE notes that the equations in AHRI 1500-2015 calculate input rate 
using the same variables as the calculation of gas consumption in the 
denominator of the equation for calculating thermal efficiency in ANSI 
Z21.10.3-2015, with the addition of a time term to yield an input rate 
rather than a gas consumption value. In the May 2016 NOPR, DOE proposed 
adding a requirement to the DOE test procedure that values of fuel

[[Page 79306]]

input rate for each unit tested be rounded to the nearest 1,000 Btu/h. 
81 FR 28588, 28622-28623 (May 9, 2016).
    Bradford White, Raypak, and Rheem stated that the fuel input rate 
should not be rounded to the nearest 1,000 Btu/h. (Bradford White, No. 
21 at p. 12; Raypak, No. 28 at pp. 4-5; Rheem, No. 34 at p. 13) Raypak 
and Rheem argued that if rounding to the nearest 1,000 Btu/h were of 
value to the end user for distinguishing amongst models of CWH 
equipment, then there would already be units rated with such precision 
on the market. (Raypak, No. 28 at pp. 4-5; Rheem, No. 34 at p. 13) 
Because DOE is not adopting its proposed regulations regarding 
certification of fuel input rate, DOE is also not adopting the proposed 
requirement that the certified fuel input rate be rounded to the 
nearest 1,000 Btu/h.
2. Enforcement Provisions
    In the May 2016 NOPR, DOE also proposed provisions regarding fuel 
input rate during DOE enforcement testing. 81 FR 28588, 28623 (May 9, 
2016). Specifically, DOE proposed that the overall fuel input rate for 
the thermal efficiency test would be measured and compared against the 
fuel input rate certified by the manufacturer. DOE proposed that if the 
measured fuel input rate determined during an enforcement test is 
within  2 percent of the certified value, then DOE would 
use the certified value when determining the applicable equipment class 
for a model. If the measured fuel input rate is not within  
2 percent of the certified value, then DOE would attempt to bring the 
fuel input rate to within  2 percent of the certified 
value. To do so, DOE would first adjust the gas pressure within the 
range allowed by the test procedure in an attempt to increase or 
decrease the fuel input rate to achieve  2 percent of the 
rated input certified by the manufacturer. If the fuel input rate is 
still not within  2 percent of the rated input, DOE would 
then attempt to modify the gas inlet orifice (e.g., drill) accordingly. 
Finally, if these measures do not bring the fuel input rate to within 
 2 percent of the rated input, DOE would use the measured 
fuel input rate when determining the equipment class. DOE proposed 
these provisions to provide manufacturers with additional information 
about how DOE will evaluate compliance with its energy conservation 
standards for CWH equipment.
    Several commenters disagreed with DOE's proposed provisions related 
to fuel input rate in enforcement testing, and argued that DOE should 
contact the manufacturer if unable to reach the certified input rate 
during enforcement testing. (Bock, No. 19 at p. 2; Bradford White, No. 
21 at p. 12; AHRI, No. 26 at p. 3; Rheem, No. 34 at p. 13) Bock further 
stated that by running an efficiency test at an input rate varying by 
more than  2 percent from the certified value, DOE would 
essentially be testing a new model. (Bock, No. 19 at p. 2) AHRI further 
argued that the enforcement provisions are unnecessary, and that AHRI 
has never had any issues achieving the manufacturer-specified input 
rating during testing. AHRI also asserted that a unit that cannot be 
put ``on-rate'' is not representative of the model, assuming there are 
no issues with the fuel supply. (AHRI, No. 26 at p. 3) Rheem further 
stated that a model should not be penalized if the fuel used in DOE's 
enforcement testing has a higher heating value such that the input 
rating could not be achieved within  2 percent of the rated 
input. (Rheem, No. 34 at p. 13) Bradford White also stated that if the 
rated input cannot be achieved, there must be an underlying reason, and 
that the model cannot be fairly evaluated. (Bradford White, No. 21 at 
p. 12) Joint Advocates commented that DOE should use the measured fuel 
input rate for all enforcement testing, while allowing for adjustment 
of gas pressure. (Joint Advocates, No. 32 at p. 2)
    DOE's proposed enforcement provisions regarding fuel input rate 
were intended to avoid invalid tests, such that even if DOE could not 
achieve a fuel input rate within  2 percent of the 
certified value, a unit could still be tested and compliance with the 
corresponding energy conservation standard(s) could still be 
determined. DOE disagrees with AHRI's point that the enforcement 
provisions for fuel input rate are unnecessary because AHRI has never 
had an issue achieving the rated input. DOE attempts to ensure that it 
is able to obtain a valid test result in all cases, and these 
provisions provide manufacturers of notice how DOE will proceed in the 
event that the test cannot achieve the rated input. DOE notes that, if 
units are always shipped by manufacturers such that the rated input 
 2 percent can be achieved during enforcement testing, then 
DOE will have no cause to apply these provisions. DOE also disagrees 
with Rheem's assertion that DOE would be penalizing a model because of 
the higher heating value of fuel used in DOE's enforcement testing. As 
noted by A. O. Smith and AHRI, manufacturers must design products that 
have flexibility to safely use fuels with various energy densities. 
When issues arise during enforcement testing, such as being unable to 
achieve the certified input rating, DOE evaluates the decision of 
whether to proceed with testing or whether to involve the manufacturer 
on a case-by-case basis. If DOE carries out a test on a unit despite 
not achieving the manufacturer's rated input as part of enforcement 
testing or as part of an assessment test on a model for which DOE 
subsequently chooses to pursue an enforcement case, DOE would provide 
the manufacturer with the test results, including the fuel input rate 
and higher heating value during the test, and the manufacturer will 
have an opportunity to discuss the test with the Department. DOE 
disagrees that testing a unit at a fuel input rate other than the rated 
input necessarily would not be representative of the model.
    DOE disagrees with Joint Advocates that DOE should use the measured 
fuel input rate for all enforcement testing. DOE believes that, given 
unit-to-unit variation and variability in the higher heating value of 
fuels as pointed out by other commenters, a  2 percent 
tolerance for fuel input rate is reasonable and that, within that 
tolerance, any slight deviation should not affect a CWH equipment 
model's classification under DOE's equipment class structure (and as a 
result affect the stringency of the applicable energy conservation 
standards). Additionally, using rated input in enforcement testing if 
the measured fuel input rate is within  2 percent of the 
rated input allows manufacturers some flexibility in the fuel input 
rate at which the individual unit may operate. This allowance may be 
beneficial because, as indicated by stakeholders, the higher heating 
value of gas varies based on geographic location.
    Bradford White recommended that the following steps be taken in 
order to adjust a model's input rate: adjust the manifold pressure, 
change the gas pressure, if necessary, and modify the gas orifice(s). 
(Bradford White, No. 21 at p. 12) DOE agrees with Bradford White that 
adjusting the manifold pressure (i.e., gas outlet pressure) of CWH 
equipment could affect the fuel input rate during testing to allow it 
to be adjusted within  2 percent of the rated input, and, 
therefore, DOE is adopting this step in its regulations. (DOE's 
approach already encompasses Bradford White's latter suggestions.)
    Raypak disagreed with DOE's proposal to modify the gas orifice when 
attempting to achieve the certified fuel input rate during enforcement 
testing. Specifically, Raypak argued that several of its products use 
an engineered nozzle with a built-in venturi instead of a

[[Page 79307]]

simple orifice. Raypak also stated that DOE should follow 
manufacturer's instructions and input regarding making adjustments to 
achieve the manufacturer's rated input. (Raypak, No. 28 at p. 5)
    In response to Raypak's comments, DOE notes that its proposed 
language states that DOE would attempt each modification; therefore, 
DOE would use its expertise and discretion as well as that of the 
third-party test laboratory in attempting each modification as may be 
required to achieve within  2 percent of the rated input. 
Should a model use a nozzle rather than an orifice, DOE would not 
attempt to drill the nozzle, as the provision clearly states that only 
a gas inlet orifice would be drilled (if the unit is equipped with 
one).
    Therefore, DOE is adopting its proposed enforcement regulations for 
fuel input rate, with the additions discussed in this section. DOE also 
clarifies that the steps it is adopting that may be attempted to 
achieve a fuel input rate that is  2 percent of the rated 
input (e.g., varying gas pressure, modifying the gas inlet orifice) 
apply only to gas-fired CWH equipment, and that DOE would not attempt 
such steps for oil-fired CWH equipment.

M. Default Values for Certain Test Parameters for Commercial Water 
Heating Equipment

    DOE currently incorporates by reference Exhibits G.1 and G.2 of 
ANSI Z21.10.3-2011 (which correspond to Annexes E.1 and E.2 of ANSI 
Z21.10.3-2015) in its current test procedure for thermal efficiency and 
standby loss for CWH equipment. Some of the equipment settings for 
performing the test procedures as per Annex E.1 of ANSI Z21.10.3-2015 
(e.g., water supply pressure, venting requirements) are required to be 
specified by manufacturers. In the May 2016 NOPR, DOE proposed to 
include default values for these parameters in its test procedures, to 
be used if values are not specified in manufacturer literature shipped 
with the unit \19\ or supplemental test information. 81 FR 28588, 28623 
(May 9, 2016). Specifically, DOE proposed: (1) A default value for 
maximum water supply pressure for all CWH equipment, (2) default ranges 
of allowable gas supply pressure for CWH equipment powered with natural 
gas and propane, (3) a default value for fuel pump pressure for oil-
fired CWH equipment, and (4) a default range for CO2 reading 
for oil-fired CWH equipment. DOE determined these values from 
examination of values reported for models currently on the market.
---------------------------------------------------------------------------

    \19\ Manufacturer literature includes any information on 
settings, installation, and operation that is shipped with the 
equipment. This information can be in the form of installation and 
operation manuals, settings provided on a name plate, or product-
specific literature.
---------------------------------------------------------------------------

    In response to the May 2016 NOPR, Bradford White, AHRI, A. O. 
Smith, and Rheem disagreed with DOE's proposal and stated that default 
values are unnecessary. (Bradford White, No. 21 at p. 8; AHRI, No. 26 
at p. 15; A. O. Smith, No. 27 at p. 15, Rheem, No. 34 at p. 19) AHRI 
indicated that these values are always provided by the manufacturer. 
(AHRI, No. 26 at p. 15) Bradford White, A. O. Smith, and Rheem stated 
that these values would always be included on the nameplate as required 
by ANSI certification. (Bradford White, No. 21 at p. 8; A. O. Smith, 
No. 27 at p. 15, Rheem, No. 34 at p. 19) Rheem further argued that 
establishing a default value for maximum water supply pressure that 
differs from the maximum water supply pressure certified by some 
manufacturers is invalidating the design and construction of the water 
heater, and that the water supply pressure default value should be more 
reflective of the particular kind of CWH equipment being tested. 
(Rheem, No. 34 at p. 19)
    DOE recognizes that such safety certification requires certain 
parameters to be included on the nameplate of every model. ANSI 
Z21.10.3-2015 requires that the maximum water supply pressure and 
allowable range of gas supply pressure be included on the model 
nameplate. Therefore, DOE is not adopting default values for these 
parameters, because DOE believes that the nameplate for every model of 
CWH equipment includes these parameters. However, ANSI Z21.10.3-2015 
does not require the inclusion of oil pump pressure or CO2 
reading for oil-fired CWH equipment. Additionally, the nameplates of 
several models of oil-fired CWH equipment that DOE purchased for 
testing did not include these parameters. Therefore, DOE believes 
default values for these parameters are warranted. In this final rule, 
for oil-fired CWH equipment, DOE is adopting a default value of 100 
psig fuel pump pressure and a default allowable range of 9-12 percent 
for CO2 reading. DOE notes that these default values were 
chosen based on an assessment of values reported for models on the 
market, and that DOE did not receive any specific feedback on these 
values in response to the May 2016 NOPR. Additionally, these default 
values would only be used if values for these parameters are not 
included in any of the following: (1) Product nameplate, (2) 
manufacturer literature shipped with the unit, or (3) supplemental 
testing instructions, if submitted to DOE with the certification 
report. These default values apply to oil-fired commercial water 
heating equipment other than residential-duty commercial water heaters.

N. Certification Requirements

    In the May 2016 NOPR, DOE proposed several changes to its 
certification requirements for commercial water heating equipment \20\ 
at 10 CFR part 429. 81 FR 28588, 28635-28636 (May 9, 2016). 
Specifically, DOE proposed to add two requirements to 10 CFR 429.44 for 
certification of instantaneous water heaters and hot water supply 
boilers. First, DOE proposed to add that manufacturers must certify 
whether instantaneous water heaters or hot water supply boilers contain 
submerged heat exchangers or heating elements, in order to allow for 
proper classification of units under DOE's proposed definition for 
``storage-type instantaneous water heater.'' Second, DOE proposed to 
add that manufacturers must certify whether instantaneous water heaters 
or hot water supply boilers require flow of water through the water 
heater to initiate burner ignition.
---------------------------------------------------------------------------

    \20\ DOE is also making an editorial change to the certification 
report provisions in 10 CFR 429.44(c) for commercial water heating 
equipment by replacing of the term ``water heater'' and 
abbreviations of water heater (i.e., WH) with the term ``water 
heating.''
---------------------------------------------------------------------------

    AHRI argued that DOE's proposed certification requirements are 
unnecessary given AHRI's comments on DOE's other proposals in the May 
2016 NOPR. Specifically, AHRI argued that when all of AHRI's comments 
are considered, six separate appendices might not be needed in the test 
procedures for CWH equipment, and some of the proposed certification 
requirements might not be needed for determining which test procedure 
to use. (AHRI, No. 26 at p. 15) Regarding the proposed certification 
requirement for classifying storage-type instantaneous water heaters, 
A. O. Smith and Rheem objected to the term ``submerged heat exchanger'' 
being used to define storage-type instantaneous water heaters, and 
Bradford White argued that the storage-type instantaneous water heater 
class is unnecessary. (Bradford White, No. 19 at pp. 12-13; A. O. 
Smith, No. 27 at p. 16; Rheem, No. 34 at p. 20) A. O. Smith further 
commented that manufacturers should also certify whether a water heater 
is activated by a remote control or sensor, and if present, the default

[[Page 79308]]

duration of the off delay for any integral pump off delay switch. (A. 
O. Smith, No. 27 at p. 16) Raypak commented that it generally supported 
DOE's proposed changes to the certification requirements, but that DOE 
should also consider: (1) Other kinds of water heaters that require 
flow-through to initiate burner ignition, and (2) water heaters that 
are activated by a remotely-located thermostat. (Raypak, No. 28 at p. 
4)
    Given the test procedure amendments DOE is adopting in this final 
rule, DOE disagrees with AHRI and continues to believe that additional 
certification requirements for instantaneous water heaters are 
warranted. DOE's definition for ``storage-type instantaneous water 
heater'' adopted in this final rule does not include the term 
``submerged heat exchanger,'' to which commenters objected, and instead 
includes a provision that the water heater includes a storage tank with 
a storage volume greater than or equal to 10 gallons. DOE's definition 
of ``storage-type instantaneous water heater'' is further discussed in 
section III.G.4 of this final rule. Therefore, for the equipment class 
of instantaneous water heaters with a storage volume of greater than or 
equal to 10 gallons, DOE is adopting a certification requirement of 
whether the water heater includes a storage tank with a storage volume 
greater than or equal to 10 gallons. DOE's adopted definition for 
``storage-type instantaneous water heater'' is discussed in section 
III.G.4 of this final rule.
    DOE agrees with the comments on flow-activated instantaneous water 
heaters, specifically that the certification requirements should 
identify water heaters activated by a remote temperature sensor and if 
present, the default duration of the off delay for any integral pump 
off delay switch. Section III.I of this final rule explains that DOE 
has decided to adopt separate standby loss test procedures for 
internally-activated instantaneous water heaters than for flow-
activated instantaneous water heaters and remote-sensor-based 
thermostatically activated (or externally-thermostatically activated) 
instantaneous water heaters. To ensure that the appropriate standby 
loss test procedure was used to rate instantaneous water heaters and 
hot water supply boilers, DOE is adding certification requirements to 
differentiate between the two kinds of CWH equipment. In addition, DOE 
is also adopting two modifications to the standby loss test procedure 
for instantaneous water heaters and hot water supply boilers that 
include: (1) Allowing two options for the methodology to determine the 
storage volume (either a weight-based method or a calculation-based 
method; see section III.H.2 for additional details); and (2) allowing a 
delay in the starting of the standby loss test to account for pump 
purge (see section III.H.3.e). Therefore, in this final rule, DOE 
requires certification of which methodology was used to determine the 
certified value for storage volume, and whether the water heater is 
equipped with an integral pump purge functionality, and if so, the 
default duration of the pump off delay. The certification for pump 
purge functionality is only required for instantaneous water heaters 
that are either flow-activated or externally-thermostatically activated 
and that have a storage capacity greater than or equal to ten gallons.

O. Other Issues

    Several stakeholders expressed legal, procedural, and practical 
concerns regarding the amendments proposed in the May 2016 NOPR. These 
comments are discussed in detail in the subsections below.
1. Timing of the Test Procedure and Energy Conservation Standards 
Rulemakings
    Several commenters expressed concerns regarding the timing of the 
test procedure and energy conservation standards revisions for CWH 
equipment, and requested that DOE delay (or suspend) its energy 
conservation standards rulemaking until after the finalization of the 
test procedure. (AHRI, No. 26 at p. 15; EEI, No. 29 at p. 2; Gas 
Associations, No. 22 at p. 2; Raypak, No. 28 at p. 1; Bradford White, 
No. 21 at p. 1) The commenters also opined that DOE has violated the 
procedures established in 10 CFR part 430, subpart C, Appendix A, 
Section 7(c) (which commenters referred to as the ``Process Rule''), 
which states that a final test procedure will be issued prior to the 
NOPR for proposed standards. (EEI, No. 29 at p. 2; Gas Associations, 
No. 22 at p. 2; Raypak, No. 28 at p. 1; Bradford White, No. 21 at p. 1) 
Bradford White also disagreed with DOE's assertion in the May 2016 NOPR 
that it is not aware of any rules or regulations that duplicate, 
overlap, or conflict with the proposed test procedure rule.
    Rheem stated that it believes that the proposed definitional 
changes to CWH equipment and applicable test procedure changes will 
alter the efficiency ratings of CWH equipment and noted that DOE must 
determine if the minimally-compliant models will continue to meet the 
current energy conservation standards if the proposed test procedure 
changes are finalized. Further, Rheem argued that in the May 2016 NOPR, 
DOE concluded that the proposed changes would not ``significantly 
alter'' the current ratings, but that the statute does not require a 
``significant'' standard. (Rheem, No. 34 at pp. 3-4)
    In response, DOE does not believe that the timing of the test 
procedure and standards rulemakings has negatively impacted 
stakeholders' ability to provide meaningful comment on this test 
procedure rulemaking. The May 2016 NOPR proposed amendments to 
incorporate provisions of the latest industry standard (i.e., ANSI Z21 
10.3-2015), which was developed by a consensus-based ANSI process, and 
was released in November 2015. The test procedures proposed in the May 
2016 NOPR and adopted in this final rule either reference ANSI 
Z21.10.3-2015 directly or are largely based on ANSI Z21.10.3-2015. In 
the May 2016 NOPR, DOE also addressed several issues raised by 
stakeholders in response to the February 2014 RFI. For example, the 
standby loss test procedure for flow-activated instantaneous water 
heaters adopted in this final rule was identified as an issue by AHRI 
in response to the February 2014 RFI. In response to the May 2016 NOPR, 
stakeholders provided detailed, insightful comments on all aspects of 
the proposal, including those proposals which are not included in ANSI 
Z21.10.3-2015, which shows that industry was able to carefully consider 
the proposed method and how it compared to the current Federal method 
of test. Further, DOE has also incorporated several recommendations 
received from stakeholders in response to the May 2016 NOPR (e.g., 
adopting a calculation-based test to determine storage volume, adding 
steady-state requirements instead of soak-in period for thermal 
efficiency test of storage water heaters, and using AHRI-recommended 
rating conditions for the CHWPH test procedure). Furthermore, DOE 
granted a 30-day extension of the comment period (Docket EERE-2014-BT-
STD-0042) to ensure stakeholders had sufficient time to consider the 
proposed test procedure changes in relation to the proposed standards. 
81 FR 51812 (August 5, 2016). Therefore, DOE concluded that 
stakeholders have had adequate time to provide meaningful comments on 
DOE's analysis and results in this test procedure rule.
    Regarding the commenters' assertions that DOE has violated the 
provisions of 10 CFR 430, subpart C, appendix A,

[[Page 79309]]

DOE notes that Appendix A established procedures, interpretations, and 
policies to guide DOE in the consideration and promulgation of new or 
revised appliance efficiency standards under EPCA. (See section 1 of 10 
CFR 430 subpart C, appendix A) These procedures are a general guide to 
the steps DOE typically follows in promulgating energy conservation 
standards. The guidance recognizes that DOE can and will, on occasion, 
deviate from the typical process. (See 10 CFR part 430, subpart C, 
appendix A, section 14(a)) In this particular instance, DOE deviated 
from its typical process due to statutorily prescribed deadlines for 
both the test procedure and standards rulemaking. As discussed 
previously in this notice, there have recently been updates to the 
industry testing standard (ANSI Z21.10.3), as well as petitions for 
waiver submitted to DOE by stakeholders requesting an alternative test 
method for flow-activated instantaneous water heaters. DOE is also 
aware of issues with the existing DOE test method having certain 
ambiguous provisions in the test set-up, conditions, and operation that 
could allow for inconsistent application and could lead to differing 
results across different test labs. DOE believes it is imperative to 
update the test method to remedy these issues as soon as possible. 
Therefore, DOE decided to amend the existing test procedure while 
continuing with the energy conservation standards rulemaking in 
parallel. The comments pertaining to the timing of the energy 
conservation standards rulemaking are addressed separately in the final 
rule for the energy conservation standards of CWH equipment.
    In response to Rheem's comment, DOE notes that by ``significantly 
alter,'' DOE meant that the measured energy efficiency or consumption 
would not be altered from the current test method to an extent that the 
current minimum standard must be adjusted. All of the provisions being 
adopted in this final rule either clarify the existing test method, 
improve repeatability of the existing test method, or establish a test 
method for equipment that either previously did not have a method 
(e.g., CHPWH) or for which the test method did not work (e.g., flow-
activated instantaneous water heaters). However, the actual procedure 
for measuring the thermal efficiency and standby loss remains largely 
the same, and, thus, DOE continues to believe that efficiency ratings 
are not affected. Rheem did not provide any information as to which 
specific changes it believes would have an effect on efficiency 
ratings, other than the ``definitional changes.'' While definitions are 
an integral part of determining equipment classification, and thus, the 
applicability of the test method, DOE notes that they do not change the 
actual test method, and thus, would not impact the ratings. DOE 
understands that the changes to the definitions may cause certain water 
heaters that manufacturers currently classify as commercial equipment 
to be classified as consumer products. However, as discussed in section 
III.G.1, DOE has concluded that under EPCA, these products have always 
been covered consumer products. Therefore, this is not a change that 
would warrant reconsideration of the energy conservation standards 
under 42 U.S.C.6293(e).
2. Other Comments
    The Gas Associations recommended that DOE adopt additional 
electrical consumption requirements, stating that the current test 
procedure only measures fossil fuel energy consumption without 
considering electrical usage. The Gas Associations further stated that 
the electrical energy consumption should be calculated using a source-
based method rather than a site-based method. (Gas Associations, No. 22 
at p. 2)
    DOE disagrees with the comments from the Gas Associations. Both the 
current and the amended test procedures require the measurement of the 
electricity consumption by CWH equipment during the thermal efficiency 
and standby loss test, and the thermal efficiency and standby loss 
metrics account for the electricity use during the test. The equations 
for calculating the thermal efficiency and standby losses of storage 
and instantaneous water heaters require the addition of the measured 
electrical energy consumption to the total fossil fuel consumption, so 
electrical energy use is taken into account. Regarding the suggestion 
to use a source-based value for electrical energy consumption, DOE 
notes that such an approach would be inconsistent with the accounting 
of the gas consumption, which is based on site energy consumption, and 
inconsistent with the approach used in ANSI Z21.10.3-2015 to account 
for electrical energy consumption. Therefore, DOE does not believe an 
additional source-based electrical consumption metric is necessary.
    CA IOUs requested that DOE release anonymized equipment testing 
data to allow stakeholders to provide stronger comments and strengthen 
the rulemaking process. (CA IOUs No. 23 at p. 3) Several proposals to 
which DOE believes this comment was likely directed are not adopted in 
this final rule (i.e., narrowing the tolerance on ambient room 
temperature from 10 [deg]F to 5 [deg]F, establishing an ambient 
humidity requirement, and the standby loss test procedure for unfired 
hot water storage tanks). In regards to DOE's testing of flow-activated 
instantaneous water heaters, DOE notes that these tests were conducted 
in order to ensure that DOE's proposed test procedures could be 
conducted as written. For CHPWHs, DOE described in extensive detail in 
the May 2016 NOPR the evaporator entering air conditions, the 
capacities of the units, and the entering water temperatures that 
helped inform the rating conditions that were proposed for rating 
CHPWHs. DOE has not provided information on the units tested and the 
efficiency or standby loss results obtained to protect the 
confidentiality of the manufacturers of these products. Further, DOE 
did not conduct any additional testing as part of this final rule. 
Therefore, this final rule does not include any additional testing data 
that were not presented in the May 2016 NOPR.
3. Waiver Requests
    DOE received waiver requests or interim waiver requests from A. O. 
Smith, HTP, Thermal Solutions, Raypak, and RBI.\21\ The petitioners 
asserted that DOE's existing test method for determining standby loss 
applies to thermostatically activated models only, and is not 
appropriate for flow-activated models. The petitioners requested the 
use of alternative procedures for measuring the standby loss of flow-
activated instantaneous water heaters. As described in section III.H, 
DOE is adopting a test procedure specifically for commercial 
instantaneous CWH equipment that is flow activated or externally 
thermostatically activated. Therefore, DOE believes that this final 
rule addresses the petitioners' concerns. Because the need for a waiver 
has been overtaken by DOE's adoption of a method of test for the basic 
models for which each of the petitioners sought a waiver, DOE is 
denying these petitions for waiver. Petitioners must begin using

[[Page 79310]]

this test procedure as of the effective date of the final rule.
---------------------------------------------------------------------------

    \21\ A.O. Smith: Case No. WH-001, requested interim waiver (no 
notice was published for this request). HTP: Case No. WH-002, 81 FR 
36295 (June 6, 2016).
    Thermal Solutions: Case No. WH-003, 81 FR 36284 (June 6, 2016).
    Raypak: Case No. WH-004, 81 FR 36288 (June 6, 2016).
    RBI: Case No. WH-005, requested interim waiver (no notice was 
published for this request).
---------------------------------------------------------------------------

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Orders 12866

    The Office of Management and Budget (OMB) has determined that test 
procedure rulemakings do not constitute ``significant regulatory 
actions'' under section 3(f) of Executive Order 12866, ``Regulatory 
Planning and Review,'' 58 FR 51735 (Oct. 4, 1993). Accordingly, this 
regulatory action was not subject to review under the Executive Order 
by the Office of Information and Regulatory Affairs (OIRA) in the 
Office of Management and Budget (OMB).

B. Review Under the Regulatory Flexibility Act

    The Regulatory Flexibility Act (5 U.S.C. 601 et seq., as amended by 
the Small Business Regulatory Enforcement Fairness Act of 1996) 
requires preparation of an initial regulatory flexibility analysis 
(IRFA) for any rule that by law must be proposed for public comment and 
a final regulatory flexibility analysis (FRFA) for any such rule that 
an agency adopts as a final rule, unless the agency certifies that the 
rule, if promulgated, will not have a significant economic impact on a 
substantial number of small entities.
    A regulatory flexibility analysis examines the impact of the rule 
on small entities and considers alternative ways of reducing negative 
effects. Also, as required by Executive Order 13272, ``Proper 
Consideration of Small Entities in Agency Rulemaking,'' 67 FR 53461 
(August 16, 2002), DOE published procedures and policies on February 
19, 2003, to ensure that the potential impacts of its rules on small 
entities are properly considered during the DOE rulemaking process. 68 
FR 7990. DOE has made its procedures and policies available on the 
Office of the General Counsel's Web site at: http://energy.gov/gc/office-general-counsel.
    The IRFA was published as part of the May 2016 NOPR. 81 FR 28588 
(May 9, 2016). The FRFA has five sections and is published below:
1. Need for, and Objectives of, the Rule
    The Energy Independence and Security Act of 2007 (EISA 2007), 
Public Law 110-140, amended EPCA to require that at least once every 7 
years, DOE must review test procedures for each type of covered 
equipment, including CWH equipment, and either: (1) Amend the test 
procedures if the Secretary determines that the amended test procedures 
would more accurately or fully comply with the requirements of 42 
U.S.C. 6314(a)(2)-(3),\22\ or (2) publish a notice of determination not 
to amend a test procedure. (42 U.S.C. 6314(a)(1)(A)) Under this 
requirement, DOE must review the test procedures for CWH equipment no 
later than May 16, 2019, which is 7 years after the most recent final 
rule amending the Federal test method for CWH equipment.\23\
---------------------------------------------------------------------------

    \22\ 42 U.S.C. 6314(a)(2) requires that test procedures be 
reasonably designed to produce test results which reflect energy 
efficiency, energy use, and estimated operating costs of a type of 
industrial equipment (or class thereof) during a representative 
average use cycle (as determined by the Secretary), and not be 
unduly burdensome to conduct.
    42 U.S.C. 6314(a)(3) requires that if the test procedure is a 
procedure for determining estimated annual operating costs, such 
procedure must provide that such costs are calculated from 
measurements of energy use in a representative average-use cycle (as 
determined by the Secretary), and from representative average unit 
costs of the energy needed to operate such equipment during such 
cycle. The Secretary must provide information to manufacturers of 
covered equipment regarding representative average unit costs of 
energy.
    \23\ DOE published a final rule in the Federal Register on May 
16, 2012, that, in relevant part, amended its test procedure for 
commercial water-heating equipment. 77 FR 28928.
---------------------------------------------------------------------------

    This final rule prescribes test procedure amendments that will be 
used to determine compliance with energy conservation standards for CWH 
equipment (except for CHPWHs, residential-duty commercial water 
heaters, and electric instantaneous water heaters with a storage 
capacity less than 10 gallons). The amendments will: (1) Update the 
referenced industry test standards by incorporating by reference ASTM 
D2156-09, ASTM C177-13, ASTM C518-15, and sections c and f of Annex E.1 
of ANSI Z21.10.3-2015; (2) modify the required ambient conditions and 
measurement intervals for CWH equipment; (3) change the required test 
set-up for storage water heaters and storage-type instantaneous water 
heaters; (4) change the method for setting the thermostat for gas-fired 
and oil-fired storage water heaters and storage-type instantaneous 
water heaters from measurement of mean tank temperature to measurement 
of top tank sensor water temperature and clarify the method for setting 
thermostats on electric storage water heaters with multiple 
thermostats; (5) establish new requirements for establishing steady-
state operation and a soak-in period; (6) define ``storage-type 
instantaneous water heater'' and modify several definitions for 
consumer water heaters and commercial water heating equipment included 
at 10 CFR 430.2 and 10 CFR 431.102, respectively; (7) include a new 
test method for measurement of standby loss for instantaneous water 
heaters and hot water supply boilers (including internally 
thermostatically-activated, externally thermostatically-activated and 
flow-activated instantaneous water heaters); (8) specify temperature-
sensing locations, water valve locations, and clarifications for using 
a recirculating loop for thermal efficiency and standby loss testing of 
instantaneous water heaters and hot water supply boilers; (9) include a 
new test method for rating commercial heat pump water heaters; (10) 
establish a procedure for determining the fuel input rate of gas-fired 
and oil-fired CWH equipment and specify DOE's measures to verify fuel 
input rate; (11) add default values for certain testing parameters for 
oil-fired commercial water heating equipment; and (12) modify DOE's 
certification requirements for commercial water heating equipment. DOE 
reviewed all of these amendments to the existing test procedure under 
the provisions of the Regulatory Flexibility Act and the policies and 
procedures published on February 19, 2003. 68 FR 7990. Accordingly, DOE 
has prepared the following FRFA for the equipment that is the subject 
of this rulemaking.
2. Significant Issues Raised in Response to the IRFA
    The Department did not received any comment that directly addressed 
the IRFA. However, DOE received several comments from stakeholders that 
referenced the impact of amended test procedures for CWH equipment on 
small businesses.
    In the May 2016 NOPR, DOE proposed to establish a requirement to 
maintain ambient relative humidity at 60 percent  5 percent 
during the thermal efficiency and standby loss test for gas-fired and 
oil-fired CWH equipment. 81 FR 28588, 28597-28598 (May 9, 2016). HTP 
commented that complying with this proposed humidity requirement would 
impose a significant burden to small businesses such as HTP, and would 
require substantial renovations to their testing lab that cost 
$100,000-$250,000. (HTP, No. 24 at p. 1) In this final rule, DOE is not 
adopting an ambient relative humidity requirement; therefore, DOE 
believes that this concern of impact to small manufacturers is 
mitigated.
    In the May 2016 NOPR, DOE also proposed to decrease the length of 
required measurement intervals to 30 seconds for both the thermal 
efficiency and standby loss tests. 81 FR 28588, 28597 (May 9, 2016). To 
accommodate DOE's proposed time intervals for data collection, AHRI 
commented that some manufacturers might need to upgrade

[[Page 79311]]

their facilities, and Raypak and Rheem argued that small manufacturers 
might need to purchase or upgrade data acquisition systems. (AHRI, No. 
26 at pp. 6-7; Raypak, No. 28 at pp. 6-7; Rheem, No. 34 at p. 5)
    DOE disagrees that its proposed measurement intervals would require 
costly upgrades to lab facilities for any manufacturers, including 
small businesses. Given that DOE's proposed measurement interval was 
only slightly different from the current requirement for the thermal 
efficiency test--30 seconds vs 1 minute--DOE does not believe that this 
proposal would require any upgrades. The duration of the standby loss 
test exceeds 24 hours and can reach up to 48 hours; therefore, DOE does 
not believe it is likely that any manufacturers, including small 
businesses, are performing this test without an automated data 
acquisition system. The one-time cost of a data acquisition system 
would likely be much less than the recurring labor costs of having a 
lab technician constantly monitor and record measurements for every 
standby loss test for up to 48 hours. DOE notes that no stakeholders 
have commented to DOE that they do not use data acquisition systems for 
testing of CWH equipment. Additionally, DOE does not believe that 
increasing the frequency of data collection would require significant 
upgrades to existing data acquisition systems. Rather, DOE believes 
that changing the measurement frequency would require a simple one-time 
software change and that the additional amount of data collected could 
easily be stored given the low cost of computer storage. Additionally, 
DOE is not adopting any requirements in this final rule that would 
require measurement with a data acquisition system other than time and 
temperature. Therefore, DOE does not expect the required data 
collection intervals adopted in this final rule--1 minute for both the 
thermal efficiency and standby loss tests--to impose a significant 
burden on any manufacturers, including small businesses.
    In the May 2016 NOPR, DOE also proposed to adopt a standby loss 
test for unfired hot water storage tanks. 81 FR 28588, 28597 (May 9, 
2016). DOE received numerous comments on this topic, and is still 
considering those comments. Therefore, DOE will address the comments 
and its proposed test procedure for unfired hot water storage tanks in 
a separate rulemaking notice.
    In the May 2016 NOPR, DOE proposed a standby loss test method for 
flow-activated instantaneous water heaters. 81 FR 28588, 28607-28615 
(May 9, 2016) DOE received comments from Bradley expressing concern 
with the complexity and burden associated with the test procedure. 
Bradley notes that it manufactures highly specialized water heaters and 
the burden to test their products with DOE's proposed test procedure 
would be an extreme financial burden to the business while not 
resulting in meaningful energy savings for customers. Bradley also 
expressed concern with the test procedure, specifically with regards to 
the method of test (including the standby loss equation) and the method 
proposed to determine the storage volume. Bradley suggested simplifying 
the test procedure would reduce the burden on small businesses that 
manufacture these specialized water heaters. (Bradley, No. 33 at pp. 1, 
3-4)
    The concerns expressed by Bradley with regards to the testing 
burden, pertain to instantaneous water heaters and hot water supply 
boilers that have a storage volume less than 10 gallons. DOE notes that 
maximum standby loss standards are currently only prescribed for 
instantaneous water heaters and hot water supply boilers with rated 
storage volume greater than or equal to 10 gallons. In the NOPR for the 
ongoing energy conservation standards rulemaking for CWH equipment, DOE 
did not propose standby loss standards for instantaneous water heaters 
with rated storage volume less than 10 gallons. 81 FR 34440 (May 31, 
2016). Consequently, manufacturers are not required to test or certify 
their instantaneous water heaters and hot water supply boilers for 
standby loss, if the model is an either an electric instantaneous water 
heater or is a gas or oil-fired instantaneous water heater with a 
storage volume less than 10 gallons.
    With regard to the technical concerns expressed by Bradley, DOE 
notes that it has responded to these comments in section III.H of this 
final rule. Specifically, DOE notes that in section III.H.2 of the 
final rule notice it has permitted the use of calculations based on 
physical dimensions and design drawings to determine the storage volume 
of instantaneous water heaters and hot water supply boilers (including 
flow-activated instantaneous water heaters). DOE has also decided to 
include additional provisions to allow water heaters that are not 
capable of meeting the required outlet water temperature (due to in-
built safety features that restrict the maximum temperature within the 
unit), to conduct the test using the maximum water temperature the unit 
is capable of achieving. DOE believes that if manufacturers choose to 
rate their products using the test procedure adopted by DOE in this 
final rule, then these provisions will be beneficial in simplifying the 
test procedure particularly for the CWH equipment with in-built safety 
features that restrict the rise in water temperature.
3. Description and Estimate of the Number of Small Entities Affected
    For manufacturers of covered CWH equipment, the Small Business 
Administration (SBA) has set a size threshold, which defines those 
entities classified as ``small businesses'' for the purposes of the 
statute. DOE used the SBA's small business size standards to determine 
whether any small entities would be subject to the requirements of the 
rule. (see 13 CFR part 121) The size standards are listed by North 
American Industry Classification System (NAICS) code and industry 
description and are available at: https://www.sba.gov/sites/default/files/Size_Standards_Table.pdf. Manufacturing of CWH equipment is 
classified under NAICS 333318, ``Other Commercial and Service Industry 
Machinery Manufacturing.'' \24\ The SBA sets a size threshold of 1,000 
employees or fewer for a manufacturer that falls under this category to 
qualify as a small business.
---------------------------------------------------------------------------

    \24\ On October 1, 2012, the NAICS code for ``Other Commercial 
and Service Industry Machinery Manufacturing,'' which includes 
manufacturing of commercial water heating equipment, changed from 
333319 to 333318.
---------------------------------------------------------------------------

    To estimate the number of companies that could be small business 
manufacturers of equipment covered by this rulemaking, DOE conducted 
market research and created a database of CWH equipment manufacturers. 
DOE's research involved industry trade association membership 
directories (including AHRI \25\), public databases (e.g., the 
California Energy Commission Appliance Efficiency Database,\26\ DOE's 
Compliance Certification Database \27\), individual company Web sites, 
and market research tools (e.g., Hoovers reports \28\) to create a list 
of companies that manufacture equipment covered by this rulemaking. DOE 
screened out companies that do not manufacture equipment affected by 
this rule, do not meet the definition of a ``small business,'' or are 
foreign owned and

[[Page 79312]]

operated. Based upon this analysis and comprehensive search, DOE 
identified 29 manufacturers of CWH equipment affected by this 
rulemaking (excluding rebranders). Of these, DOE identified 18 as 
domestic small manufacturers.
---------------------------------------------------------------------------

    \25\ The AHRI Directory is available at: www.ahridirectory.org/ahriDirectory/pages/home.aspx.
    \26\ The CEC database is available at: http://www.energy.ca.gov/appliances/.
    \27\ DOE's Compliance Certification Database is available at: 
https://www.regulations.doe.gov/certification-data/.
    \28\ Hoovers Inc., Company Profiles, Various Companies 
(Available at: www.hoovers.com/).
---------------------------------------------------------------------------

4. Description and Estimate of Compliance Requirements
    In the following sections, DOE discusses the potential burdens that 
could be faced by manufacturers of CWH equipment, particularly small 
businesses, as a result of each of the test procedure amendments being 
adopted in this final rule.
Updated Industry Test Methods
    In this final rule, DOE is updating the referenced industry test 
method in its test procedures for CWH equipment from ANSI Z21.10.3-2011 
(Exhibits G.1 and G.2) to sections c and f of Annex E.1 of ANSI 
Z21.10.3-2015. DOE does not expect that this update will impact the 
requirements, conditions, or duration of DOE's test procedures. DOE 
only identified one substantive difference in ANSI Z21.10.3-2015 from 
the currently referenced version ANSI Z21.10.3-2011--the standby loss 
equation. Because DOE concluded that the equation in the currently 
referenced ANSI Z21.10.3-2011 is correct and retains that equation in 
its test procedures, this updated reference to the industry test method 
will not affect conduct of or ratings from DOE's test procedure.
    DOE's current test procedure, specified at 10 CFR 431.106, also 
requires that flue gases from oil-fired CWH equipment not contain smoke 
that exceeds No. 1 smoke, as determined by ASTM Standard D2156-80. In 
this final rule, DOE is incorporating by reference the most recent 
version of this test method, ASTM D2156-09. DOE did not identify any 
significant differences between the two versions of this test method; 
therefore, DOE concluded that this updated reference should not affect 
results from its test procedure.
    Additionally, DOE is adopting several clarifications to the 
procedure for determining smoke spot number because the current 
procedure as specified in 10 CFR 431.106 does not specify the timing or 
location of measuring the smoke spot number. DOE considers conduct of 
the smoke spot test and measurement of CO2 reading before 
the thermal efficiency test begins to be a less burdensome method than 
measuring during the test. Therefore, the Department does not consider 
this clarification likely to increase testing burden to manufacturers. 
Additionally, DOE clarifies situations when the smoke spot test and 
measurement of CO2 reading are not needed to reduce burden. 
Finally, DOE specifies the location within the flue for determination 
of smoke spot number. Given that this requirement was adopted from an 
industry-accepted test method for similar commercial HVAC equipment, 
DOE selected this location because it was the least likely to increase 
burden to manufacturers, DOE's current definition for ``R-value'' at 10 
CFR 431.102 references two industry test methods, ASTM C177-97 and ASTM 
C518-91. DOE is incorporating by reference the most recent versions of 
these test methods: ASTM C177-13 and ASTM C518-15. DOE did not identify 
any significant differences in the procedures for measuring R-value 
between the two versions of ASTM C177 or between the two versions of 
ASTM C518. Therefore, this updated reference should not affect results 
for calculation of R-value per DOE's definition at 10 CFR 431.102.
Ambient Test Conditions
    DOE is adopting several amendments to its required ambient 
conditions for CWH equipment. Specifically, DOE is making the following 
modifications: (1) Setting a maximum air draft requirement of 50 ft/min 
as measured prior to beginning the steady-state verification period or 
the standby loss test; (2) decreasing the allowed variance from mean 
ambient temperature from  7.0[emsp14][deg]F to  
5.0[emsp14][deg]F; (3) requiring measurement of test air temperature--
the temperature of entering combustion air--and requiring the test air 
temperature not vary by more than  5[emsp14][deg]F from the 
ambient room temperature at any measurement interval during the steady-
state verification period and the thermal efficiency and standby loss 
tests for gas-fired and oil-fired CWH equipment; and (4) decreasing the 
time interval for data collection from fifteen minutes to one minute 
for the standby loss test.
    For the first modification, depending on the conditions in the 
manufacturer's testing area, the manufacturer may need to protect the 
testing area from drafts greater than 50 ft/min. This draft protection 
could be accomplished by using wind barriers such as moveable walls, 
minimizing the opening and closing of doors near the test stand, or 
sealing windows. To measure draft velocity, manufacturers may have to 
purchase instrumentation that DOE estimates could cost up to $250. 
However, any manufacturer of residential water heaters should already 
have this instrumentation and be able to comply with this requirement, 
because it is similar to the requirement established for testing 
residential water heaters in the July 2014 final rule. 79 FR 40542, 
40569 (July 11, 2014). DOE notes that measurement of air draft is only 
required at the beginning of each test; therefore, draft-measuring 
devices used for testing of CWH equipment do not need the capability to 
connect to a data acquisition system.
    For the second modification, manufacturers need to maintain a 
slightly more stringent allowed variance from the average ambient room 
temperature over the course of the test. DOE received several comments 
suggesting that DOE adopt this decreased variance, indicating that this 
decrease in the allowed variance would not be burdensome to 
manufacturers, and that manufacturers could accommodate this decrease 
in the allowed variance with their existing lab HVAC systems. Therefore 
does not anticipate that this modification will impose a significant 
burden to manufacturers, including small businesses.
    For the third modification, manufacturers need to measure the test 
air temperature, which is measured within two feet of the combustion 
air inlet. While this requirement was adopted from an industry test 
method for commercial packaged boilers, AHRI 1500-2015, it was not 
previously required for testing of CWH equipment. Therefore, 
manufacturers need to install temperature sensors in close proximity to 
the air intake. However, DOE believes that a requirement for this 
temperature measurement will not present any significant testing burden 
to manufacturers, because it simply involves taking more temperature 
measurements than are already being conducted, and the temperature 
readings could be recorded using the same data acquisition software 
that is used for measuring the ambient room temperature. DOE 
anticipates that adding additional temperature sensors to an existing 
data acquisition system would be a simple, one-time task and not 
present a significant burden to manufacturers.
    Finally, DOE proposes reducing the time interval for data 
collection during the standby loss test from 15 minutes to 1 minute. 
Because the standby loss test duration is between 24 to 48 hours, DOE 
reasons that manufacturers already use a computer-connected data 
acquisition system. Additionally, manufacturers are already required to 
measure at one-minute intervals in DOE's existing thermal efficiency 
test procedure. DOE believes that changing the measurement frequency 
would require a simple one-

[[Page 79313]]

time software change and that the additional amount of data collected 
could easily be stored given the low cost of computer storage. 
Therefore, manufacturers were not expected to incur any additional 
testing costs due to the change in the relevant data recording time 
intervals, and DOE does not anticipate the one-time software change to 
impose any significant burden to manufacturers, including small 
businesses.
Test Set-Up for Storage and Storage-Type Instantaneous Water Heaters
    In this final rule, DOE specifies the location for measurement of 
supply and outlet water temperature for storage water heaters and 
storage-type instantaneous water heaters. Specifically, in the test 
set-ups adopted in this final rule, DOE has specified exact locations 
for placement of the temperature sensors in terms of total piping 
length. DOE expects these lengths to align with the piping set-ups 
currently used in most testing of CWH equipment. If the test set-up 
changes adopted in this final rule are different from the set-ups 
currently used, DOE believes that these differences would be minor and 
would simply involve adding or removing several inches of piping. 
Additionally, DOE is adopting set-ups for tank-type water heaters with 
connections on the top, side, or bottom--thereby minimizing the 
likelihood that a significant change to the set-up currently used by 
manufacturers would be needed. Further, for certain water heaters with 
horizontal water connections that cannot meet the inlet side vertically 
downward piping distance of 24 inches (as proposed in the May 2016 
NOPR), DOE allows such piping to be extended vertically downwards to 
the maximum extent possible. This would reduce the burden on 
manufacturers and small businesses from having to raise the water 
heater platform or have piping embedded under the flooring, to meet the 
24 inches of vertically downward piping distance. Therefore, DOE 
concludes that the changes adopted with regards to the test set-up for 
storage and storage-type instantaneous water heaters would not present 
a significant burden to manufacturers, including small businesses.
Unfired Hot Water Storage Tanks
    DOE is not adopting a test procedure for unfired hot water storage 
tanks in this final rule, and, therefore, there will be not any burden 
from test procedure amendments for this equipment.
Thermostat Settings for Storage Water Heaters
    DOE is modifying its procedure for setting the tank thermostat for 
gas-fired and oil-fired storage water heaters and storage-type 
instantaneous water heaters by adopting a top tank sensor water 
temperature requirement rather than a mean tank temperature 
requirement. This change was suggested by manufacturers so that their 
models can more easily meet the specified conditions in the test 
procedure without having to sacrifice thermal efficiency gains when 
designing equipment. Because the top tank sensor water temperature 
(i.e., the highest of six temperature sensors used to calculate mean 
tank temperature) is already measured in the current test method, this 
proposal would simplify DOE's test procedure, and would not create any 
additional test burden for manufacturers, including small businesses. 
DOE is also adopting a requirement that the tank be re-filled with 
supply water before re-adjusting the thermostat if the top tank sensor 
temperature requirement is not achieved. While this requirement may add 
to test time in certain cases, DOE believes that it is common industry 
practice, because this requirement is consistent with requirements in 
an industry-consensus test method, ASHRAE 118.1-2012, and DOE's test 
procedure for consumer water heaters and residential-duty commercial 
water heaters at appendix E to subpart B of 10 CFR part 430.
    DOE is also clarifying its procedure for setting thermostats for 
electric storage water heaters with multiple thermostats. DOE is 
specifying that only the top-mosttopmost and bottom-mostbottommost 
thermostats be set, and that all other thermostats and corresponding 
heating elements not operate while setting thermostats or during 
conduct of the standby loss test. DOE believes that some manufacturers 
already use DOE's adopted method, and that this method simply clarifies 
which thermostats (and corresponding heating elements) to use during 
the test. DOE's clarifications are based upon comments from a 
manufacturer and industry trade organization; based on these comments, 
DOE does not anticipate that this procedure will impose a significant 
test burden to manufacturers, including small businesses.
Steady-State Requirements and Soak-In Period
    DOE is adopting more stringent provisions for establishing steady-
state operation prior to the thermal efficiency test. These provisions 
require a 30-minute verification period, rather than the 3-minute 
period in DOE's current test procedure. However, these provisions, with 
minor modifications, were suggested by multiple commenters as being 
supported by an industry working group, as an improvement to the 
repeatability of testing of CWH equipment. DOE also understands that 
many manufacturers, including small businesses, already often run CWH 
equipment for longer than required by DOE's current test procedure to 
ensure steady-state operation prior to beginning the thermal efficiency 
test. Therefore, DOE does not expect that these more-stringent 
provisions will impose a significant burden to manufacturers, including 
small businesses.
    DOE has also added clarifying statements to its thermal efficiency 
and standby loss test procedures. Specifically, DOE is clarifying that 
during the steady-state verification period, the thermal efficiency 
test, and the standby loss test (as applicable), no settings on the 
water heating equipment can be changed until measurements for the test 
have finished. As discussed in section III.F.2, several manufacturers 
agreed to include the clarifying statements. Additionally, DOE expects 
that the majority of manufacturers already perform the thermal 
efficiency and standby loss tests in a manner as clarified in DOE's 
proposal. Therefore, DOE has concluded that its clarifying statements 
would only serve to remove any potential confusion regarding its test 
procedures, and would not add any burden to manufacturers, including 
small businesses.
    DOE is adopting a requirement that a soak-in period be conducted 
prior to the standby loss test for storage water heaters in which the 
water heater must sit without any draws taking place for at least 12 
hours from the end of a recovery from a cold start, unless the unit has 
been in operation and no settings have been changed since the end of a 
previously run efficiency test. While this soak-in period would add to 
the time required to conduct the test, it would not require extra 
personnel and would not necessitate the development of additional test 
platforms. DOE understands that a preconditioning period is already 
implemented by manufacturers as a best practice to allow the water 
heater to achieve operational temperature, so the added burden from the 
12-hour soak-in is expected to be minimal. In addition, these tests can 
be conducted in the same facilities used for the current energy testing 
of these products, so there would be no

[[Page 79314]]

additional facility costs required by this amendment.
Storage-Type Instantaneous Water Heaters
    DOE is adopting a new definition for ``storage-type instantaneous 
water heater,'' which includes instantaneous water heaters with 
integral storage tanks that have a tank volume greater than or equal to 
10 gallons. DOE believes this kind of water heater should be tested 
similar to storage water heaters. However, DOE does not currently 
prescribe separate test procedures for storage water heaters and 
instantaneous water heaters. Only in the test procedures established in 
this final rule does DOE prescribe separate standby loss test 
procedures for storage water heaters and instantaneous water heaters. 
Additionally, DOE's research suggests that manufacturers already 
categorize units falling under DOE's proposed definition for ``storage-
type instantaneous water heater'' with storage water heaters. 
Therefore, DOE does not anticipate that applying the test procedure 
prescribed for storage water heaters to storage-type instantaneous 
water heaters will present a burden for manufacturers, including small 
businesses.
Instantaneous Water Heaters and Hot Water Supply Boilers (Other Than 
Storage-Type Instantaneous Water Heaters)
    Currently, all instantaneous water heaters and hot water supply 
boilers having a capacity of 10 gallons or more are required to undergo 
the same standby loss test that is prescribed in Exhibit G.2 of ANSI 
Z21.10.3-2011. In this final rule, DOE is adopting a separate standby 
loss test procedures for: (1) Internally thermostatically-activated 
instantaneous water heaters and (2) instantaneous water heaters that 
are either flow-activated or thermostatically activated by an external 
thermostat. In addition, DOE is adopting changes to the test set-up for 
instantaneous water heaters and hot water supply boilers.
    For the changes in the test set-up, DOE is adopting: (1) Slight 
variations of Figure III.1, Figure III.2, and Figure III.3 of this 
final rule as the test set-ups for instantaneous water heaters and hot 
water supply boilers tested without a recirculating loop, and (2) 
Figure III.4 as the test set-ups for instantaneous water heaters and 
hot water supply boilers tested with a recirculating loop. Allowing the 
water heaters to be tested to the different configurations in the 
figures would be beneficial to all manufacturers, including small 
businesses, as it would allow them to use the test set-up most 
appropriate to the equipment being tested. In this final rule, DOE has 
decided to require three changes in the test set-up for instantaneous 
water heaters and hot water supply boilers: (1) Installation of an 
additional temperature sensor near the outlet of the water heater at a 
distance of one-inch (inside or outside) from the outlet port for the 
standby loss test; (2) installation of a temperature sensor in the 
outlet water piping at the second elbow (as per the test set-ups in 
Figure III.1, Figure III.2,Figure III.3, and Figure III.4 of this final 
rule); and (2) installation of an outlet water valve downstream of the 
outlet water heat trap, within a distance of 10 inches downstream from 
outlet water temperature sensor which is placed at the second elbow in 
the outlet water piping.
    These modifications in the test set-up require: (1) Addition of a 
pipe fitting to hold the outlet water temperature-sensing instrument to 
a location immediately outside the CWH equipment; (2) addition of a 
temperature sensor near the outlet to the water heater; and (2) 
movement of the outlet water valve that is already installed further 
downstream in the piping, to a location closer to the CWH equipment. 
DOE estimates that a fitting to hold the temperature sensor would cost 
approximately $50, while the temperature sensor itself would cost about 
$100 (for a thermocouple). DOE reasons that the benefits of better 
representation of the outlet water temperature and close proximity of 
the water valves that need to be shut off to retain the hot water in 
the water heater during the standby loss test outweighs the small 
potential cost of an additional pipe fitting and temperature sensor. In 
addition to these changes, DOE is also clarifying the conditions for 
using a recirculating loop. The use of a recirculating loop is allowed 
in the current test procedure, and, thus, this modification would not 
cause an increase in testing cost. Therefore, DOE concluded that the 
adjustments described in this paragraph would not impose a significant 
burden on manufacturers, including small businesses.
    The standby loss test procedure adopted for internally 
thermostatically-activated instantaneous water heaters is similar to 
the current test procedure in Exhibit G.2 of ANSI Z21.10.3-2011 (and 
Annex E.2 of ANSI Z21.10.3-2015) that is incorporated by reference as 
DOE's test procedure. The adopted test procedure requires the use of 
the heat exchanger outlet water temperature as an approximation for the 
stored water temperature instead of the mean tank temperature which is 
required by the current test procedure. DOE notes that this adopted 
modification to the current test procedure would only change the terms 
that are used in calculating standby loss. In the previous section, DOE 
discussed the cost involved in installing an additional temperature 
sensor to record the heat exchanger outlet water temperature. 
Therefore, the only change that manufacturers will be required to make 
is to record the heat exchanger outlet water temperature during the 
standby loss test. Accordingly, DOE has concluded that these changes 
will not be unduly burdensome to manufacturers, including small 
businesses.
    For externally thermostatically-activated instantaneous water 
heaters and flow-activated instantaneous water heaters, DOE has adopted 
a test procedure that is similar to the current test procedure in 
Exhibit G.2 of ANSI Z21.10.3-2011. Similar to internally-activated 
instantaneous water heaters, the adopted test procedure for flow-
activated and externally thermostatically-activated instantaneous water 
heaters uses the outlet water temperature as an approximation for the 
stored water temperature. In addition, the adopted test procedure would 
not require the water heater to cycle-on at any point in the course of 
the test. Therefore, the amount of fuel consumption is not required to 
be recorded for standby loss calculations. As a result, these two 
modifications will simplify the test and reduce the amount of data 
processing required for calculating the standby loss metric. As a 
result, this modification will be beneficial to all manufacturers, 
including small businesses.
    The second difference pertains to the duration of the test. In the 
current test procedure, the equipment is tested until the first cut-out 
that occurs after 24 hours or 48 hours, whichever comes first. In the 
adopted standby loss test procedure for flow-activated instantaneous 
water heaters, the test ends when the outlet water temperature drops by 
35[emsp14][deg]F or after 24 hours, whichever comes first. DOE has 
concluded that it is very likely that a 35[emsp14][deg]F drop in outlet 
water temperature will occur before 24 hours. Therefore, this 
modification will likely be beneficial to all manufacturers, including 
small businesses, as it would reduce the time required to conduct the 
standby loss test. In addition, DOE notes that the maximum test length 
of 24 hours in the test method is the same as the current minimum test 
length in the

[[Page 79315]]

existing test procedure, so the adopted test will always result in a 
test length either shorter or equal to that of the current test.
    The third difference is with regard to the pump purge 
functionality. The current test procedure requires the outlet water 
valve to be closed immediately after the burner cuts out at the 
beginning of the standby loss test. In the test procedure adopted in 
this final rule, DOE has decided to allow units to use the integrated 
pump purge functionality (if so equipped) by delaying the closing of 
the outlet water valve until after the pump purge operation is 
completed. During this operation, the electricity consumed is not 
recorded for calculating the standby loss. DOE notes that the addition 
of this provision only changes the sequence of steps in the test 
procedure. As a result, DOE does not believe this modification will 
impose a significant burden on manufacturers, including small 
businesses. Rather, DOE believes that by allowing this modification, 
manufacturers will be able to benefit from the pump purge technology 
that is intended to reduce standby loss in the water heater.
    Finally, in the adopted test procedure, DOE has permitted the use 
of calculations based on CAD designs and physical dimensions to rate 
the storage volume of instantaneous water heaters and hot water supply 
boilers. The current test procedure requires the use of the weight-
based test specified in section 2.26 of ANSI Z21.10.3-2011 to determine 
the storage volume. The weight-based test requires the water heater to 
be weighed dry and then weighed after it is filled with water. The 
difference between the two weights is used to calculate the storage 
volume. DOE expects that allowing manufacturers to use their design 
drawing or physical dimensions to determine storage volume will be 
beneficial to manufacturers and save them time and cost. Therefore, DOE 
believe that this modification will be beneficial to all manufacturers, 
including small businesses.
    In summary, DOE has concluded that the standby loss test procedure 
adopted in this final rule for flow-activated, externally 
thermostatically activated and internally thermostatically activated 
instantaneous water heaters will not impose any significant additional 
burden on manufacturers.
Commercial Heat Pump Water Heaters
    DOE previously did not prescribe a test procedure for commercial 
heat pump water heaters. In this final rule, DOE adopts a new test 
procedure for measurement of the COPh of CHPWHs. However, 
manufacturers are not required to certify COPh for CHPWHs 
until DOE establishes energy conservation standards for this equipment 
based on a COPh metric. Therefore, manufacturers are not 
required to certify for COPh using the test procedure 
adopted in this final rule. However, DOE acknowledges that in the 
absence of a Federal COPh standard, some manufacturers may 
choose, at their discretion, to rate the efficiency of their CHPWHs to 
help distinguish their equipment from competitor offerings.
    DOE believes that manufacturers of CHPWHs already have the 
equipment, instrumentation, and facilities (including psychrometric 
chambers) for testing their units according to the adopted test method, 
because these will be needed for product development and measurement of 
COPh values absent a DOE test method. However, DOE 
acknowledges that some manufacturers may need to purchase equipment, 
instrumentation, or test stands for measurement of COPh 
according to the test method. For testing air-source CHPWH units, DOE 
estimates that the cost to build a test stand and a surrounding 
psychrometric chamber for the testing of CHPWHs will cost no more than 
$300,000. While the duration of the test for air-source CHWPHs is 30 
minutes, DOE estimates the total time, including the time needed for 
set-up and stabilizing the outlet water temperatures prior to the test, 
may reach five hours. At a rate of $40 per hour for a laboratory 
technician, DOE estimates the cost for this labor will be $200 per 
model tested.
    Given the small market size of air-source CHPWHs, DOE believes that 
most manufacturers without test facilities capable of testing air-
source CHPWHs according to DOE's test procedure will choose to conduct 
testing at a third-party lab. DOE estimates that the average air-source 
CHPWH manufacturer sells six models, and that the cost of testing an 
air-source CHPWH would not exceed $11,000. Therefore, the average 
testing burden for manufacturers of air-source CHPWHs without testing 
facilities should not exceed $66,000.
    For indoor water-source, ground-source closed-loop, and ground 
water-source CHPWHs, water solution conditioning and recirculation 
equipment similar to a chiller would be required for testing, in 
addition to the common instrumentation needed for testing air-source 
CHPWHs (e.g., standard piping, instrumentation, a data acquisition 
system, and test stand). DOE expects most manufacturers already have 
such equipment in order to test and provide ratings for their current 
product offerings. However, DOE acknowledges that there may be some 
manufacturers that do not currently have equipment sufficient for 
conducting DOE's adopted test procedure. DOE estimates the total cost 
of a chiller to be about $20,000. The cost of instrumentation, piping, 
and a data acquisition unit could add up to an additional $5,000. 
Therefore, DOE does not expect capital investments would exceed $25,000 
per manufacturer. DOE estimates that following the test procedure, it 
would take approximately 5-6 hours to set up the unit and to conduct 
the test. At a lab technician labor cost of $40 per hour, DOE estimates 
the total labor cost incurred to test each unit would be between $200 
and $240. Alternatively, some manufacturers, including small 
businesses, may choose to test their units at third-party laboratories 
instead of investing in in-house testing facilities. DOE estimates that 
the cost of such testing would not exceed $3,000 per unit. DOE 
estimates that manufacturers may test about 6 models annually at third-
party laboratories. Therefore, the total estimated cost burden for any 
such manufacturers would not be more than $18,000.
    Based on the adopted test procedure, the test set-up for ground-
source closed-loop, ground water-source, or indoor water-source CHPWHs 
will be similar to that for direct geo-exchange CHPWHs, with the only 
difference being that the test set-up for direct geo-exchange CHPWHs 
includes an additional solution heat exchanger. Similar to water-source 
CHPWHs, DOE expects that most manufacturers of direct geo-exchange 
CHPWHs already have such equipment in order to test and provide ratings 
for their current product offerings. DOE understands that the cost of 
this solution heat exchanger will be the only cost to be added to the 
total estimated cost for testing ground and indoor water-source CHPWHs 
in order to arrive at the estimated cost of testing a direct geo-
exchange CHPWH. DOE estimates the cost of a liquid-to-liquid heat 
exchanger to be not more than $30,000. Therefore, the total estimated 
capital investment cost for testing a direct geo-exchange CHPWH should 
not exceed $55,000. Similar to water-source CHPWH manufacturers, DOE 
understands that many manufacturers of direct geo-exchange CHPWHs, 
including small businesses, may choose to test their units at third-
party laboratories instead of investing in in-house testing

[[Page 79316]]

facilities. DOE estimates the cost of such testing will not exceed 
$5,000 per unit.
Gas Pressure
    DOE is adopting requirements that the gas supply pressure must be 
within the range specified by the manufacturer, and that the difference 
between the outlet pressure of the gas appliance pressure regulator and 
the value specified by the manufacturer on the nameplate of the unit 
being tested must not exceed the greater of:  10 percent of 
the nameplate value or  0.2 in. w.c. The first requirement 
was suggested by commenters and is consistent with the industry-
consensus test method, ANSI Z21.10.3-2015. The second requirement is 
also consistent with ANSI Z212.10.3-2015 except for the addition of an 
absolute tolerance. However, this absolute tolerance only serves to 
make the requirement more lenient than that included in ANSI Z21.10.3-
2015. Therefore, DOE does not anticipate that these changes will impose 
a significant burden to manufacturers, including small businesses.
Fuel Input Rate
    DOE is adopting provisions that the fuel input rate be determined 
at 10-minute intervals during the steady-state verification period and 
the thermal efficiency test. This requirement to determine fuel input 
rate simply requires measuring gas consumption every 10 minutes during 
the test, a change DOE expects will impose no significant burden. 
Additionally, DOE is requiring that the measured fuel input rates for 
these 10-minute periods must not vary by more than  2 
percent between any two readings. However, DOE believes that this 
requirement is consistent with the requirement in ANSI Z21.10.3-2015, 
and does not expect this requirement to impose a significant burden to 
manufacturers, including small businesses.
Default Values for Certain Test Parameters
    DOE is adding to its test procedure at 10 CFR 431.106 default 
values for certain test parameters for oil-fired CWH equipment, to be 
used if manufacturers do not report these in any of the following: (1) 
Product nameplate, (2) the literature that is shipped with the unit 
(e.g., installation and operations manual), or (3) their supplemental 
instructions. Specifically, DOE is adopting default values for fuel 
pump pressure and a range for CO2 reading for oil-fired CWH 
equipment. DOE does not expect these default values to present a 
significant burden to manufacturers because these are basic parameters 
needed for proper use of CWH equipment and are, therefore, typically 
specified by the manufacturer on the product nameplate and in 
manufacturer literature shipped with the unit.
4. Significant Alternatives to the Rule
    DOE considered alternative test methods and modifications to the 
test procedures for CWH equipment, and determined that there are no 
better alternatives than the modifications and procedures established 
in this final rule. DOE examined relevant industry test standards, and 
incorporated these standards in the final test procedures whenever 
appropriate to reduce test burden to manufacturers. Specifically, in 
this final rule DOE updates its test procedures for CWH equipment to 
incorporate by reference the following updated standards: ASTM D2156-
09, ASTM C177-13, ASTM C518-15, and sections c and f of Annex E.1 of 
ANSI Z21.10.3-2015. Additionally, DOE is incorporating by reference 
certain sections, figures, and tables in ASHRAE 118.1-2012 in the test 
procedure for measurement of COPh of commercial heat pump 
water heaters that DOE establishes in this final rule.
    Additional compliance flexibilities may be available through other 
means. For example, individual manufacturers may petition for a waiver 
of the applicable test procedure. (See 10 CFR 431.401) Additionally, 
Section 504 of the Department of Energy Organization Act, 42 U.S.C. 
7194, provides authority for the Secretary to adjust a rule issued 
under EPCA in order to prevent ``special hardship, inequity, or unfair 
distribution of burdens'' that may be imposed on that manufacturer as a 
result of such rule. Manufacturers should refer to 10 CFR part 430, 
subpart E, and part 1003 for additional details.

C. Review Under the Paperwork Reduction Act of 1995

    Manufacturers of CWH equipment must certify to DOE that their 
equipment complies with any applicable energy conservation standards. 
In certifying compliance, manufacturers must test their equipment 
according to the DOE test procedures for CWH equipment, including any 
amendments adopted for those test procedures, on the date that 
compliance is required. DOE has established regulations for the 
certification and recordkeeping requirements for all covered consumer 
products and commercial equipment, including CWH equipment. 76 FR 12422 
(March 7, 2011); 80 FR 5099 (Jan. 30, 2015). The collection-of-
information requirement for certification and recordkeeping is subject 
to review and approval by OMB under the Paperwork Reduction Act (PRA). 
This requirement has been approved by OMB under OMB control number 
1910-1400. Public reporting burden for the certification is estimated 
to average 30 hours per manufacturer, including the time for reviewing 
instructions, searching existing data sources, gathering and 
maintaining the data needed, and completing and reviewing the 
collection of information.
    Notwithstanding any other provision of the law, no person is 
required to respond to, nor shall any person be subject to a penalty 
for failure to comply with, a collection of information subject to the 
requirements of the PRA, unless that collection of information displays 
a currently valid OMB Control Number.

D. Review Under the National Environmental Policy Act of 1969

    In this final rule, DOE amends its test procedures for commercial 
water heating equipment. DOE has determined that this rule falls into a 
class of actions that are categorically excluded from review under the 
National Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.) and 
DOE's implementing regulations at 10 CFR part 1021. Specifically, this 
rule amends the existing test procedure without affecting the amount, 
quality, or distribution of energy usage, and, therefore, will not 
result in any environmental impacts. Thus, this rulemaking is covered 
by Categorical Exclusion (CX) A5 under 10 CFR part 1021, subpart D, 
which applies to any rulemaking that interprets or amends an existing 
rule without changing the environmental effect of that rule. 
Accordingly, DOE has made a CX determination for this rulemaking, and 
neither an environmental assessment nor an environmental impact 
statement is required. DOE's CX determination for this final rule is 
available at: http://energy.gov/nepa/categorical-exclusion-cx-determinations-cx/.

E. Review Under Executive Order 13132

    Executive Order 13132, ``Federalism,'' 64 FR 43255 (August 10, 
1999), imposes certain requirements on Federal agencies formulating and 
implementing policies or regulations that preempt State law or that 
have Federalism implications. The Executive Order requires agencies to 
examine the constitutional and statutory authority supporting any 
action that would limit the policymaking discretion of the States and 
to carefully assess the necessity for such actions. The Executive Order 
also requires agencies

[[Page 79317]]

to have an accountable process to ensure meaningful and timely input by 
State and local officials in the development of regulatory policies 
that have Federalism implications. On March 14, 2000, DOE published a 
statement of policy describing the intergovernmental consultation 
process it will follow in the development of such regulations. 65 FR 
13735. DOE examined this final rule and determined that it will not 
have a substantial direct effect on the States, on the relationship 
between the national government and the States, or on the distribution 
of power and responsibilities among the various levels of government. 
EPCA governs and prescribes Federal preemption of State regulations as 
to energy conservation for the equipment that is the subject of this 
final rule. States can petition DOE for exemption from such preemption 
to the extent, and based on criteria, set forth in EPCA. (42 U.S.C. 
6297(d)) Therefore, Executive Order 13132 requires no further action.

F. Review Under Executive Order 12988

    With respect to the review of existing regulations and the 
promulgation of new regulations, section 3(a) of Executive Order 12988, 
``Civil Justice Reform,'' 61 FR 4729 (Feb. 7, 1996), imposes on Federal 
agencies the general duty to adhere to the following requirements: (1) 
Eliminate drafting errors and ambiguity; (2) write regulations to 
minimize litigation; (3) provide a clear legal standard for affected 
conduct rather than a general standard; and (4) promote simplification 
and burden reduction. Regarding the review required by section 3(a), 
section 3(b) of Executive Order 12988 specifically requires that 
Executive agencies make every reasonable effort to ensure that the 
regulation: (1) Clearly specifies the preemptive effect, if any; (2) 
clearly specifies any effect on existing Federal law or regulation; (3) 
provides a clear legal standard for affected conduct while promoting 
simplification and burden reduction; (4) specifies the retroactive 
effect, if any; (5) adequately defines key terms; and (6) addresses 
other important issues affecting clarity and general draftsmanship 
under any guidelines issued by the Attorney General. Section 3(c) of 
Executive Order 12988 requires Executive agencies to review regulations 
in light of applicable standards in sections 3(a) and 3(b) to determine 
whether they are met or it is unreasonable to meet one or more of them. 
DOE has completed the required review and determined that, to the 
extent permitted by law, this final rule meets the relevant standards 
of Executive Order 12988.

G. Review Under the Unfunded Mandates Reform Act of 1995

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA) 
requires each Federal agency to assess the effects of Federal 
regulatory actions on State, local, and Tribal governments and the 
private sector. Public Law 104-4, sec. 201 (codified at 2 U.S.C. 1531). 
For a proposed regulatory action likely to result in a rule that may 
cause the expenditure by State, local, and Tribal governments, in the 
aggregate, or by the private sector of $100 million or more in any one 
year (adjusted annually for inflation), section 202 of UMRA requires a 
Federal agency to publish a written statement that estimates the 
resulting costs, benefits, and other effects on the national economy. 
(2 U.S.C. 1532(a), (b)) The UMRA also requires a Federal agency to 
develop an effective process to permit timely input by elected officers 
of State, local, and Tribal governments on a proposed ``significant 
intergovernmental mandate,'' and requires an agency plan for giving 
notice and opportunity for timely input to potentially affected small 
governments before establishing any requirements that might 
significantly or uniquely affect them. On March 18, 1997, DOE published 
a statement of policy on its process for intergovernmental consultation 
under UMRA. 62 FR 12820. (This policy is also available at 
www.energy.gov/gc/office-general-counsel under ``Guidance & Opinions'' 
(Rulemaking)) DOE examined this final rule according to UMRA and its 
statement of policy and determined that the rule contains neither an 
intergovernmental mandate, nor a mandate that may result in the 
expenditure by State, local, and Tribal governments, in the aggregate, 
or by the private sector, of $100 million or more in any year. 
Accordingly, no further assessment or analysis is required under UMRA.

H. Review Under the Treasury and General Government Appropriations Act, 
1999

    Section 654 of the Treasury and General Government Appropriations 
Act, 1999 (Pub. L. 105-277) requires Federal agencies to issue a Family 
Policymaking Assessment for any rule that may affect family well-being. 
This final rule will not have any impact on the autonomy or integrity 
of the family as an institution. Accordingly, DOE has concluded that it 
is not necessary to prepare a Family Policymaking Assessment.

I. Review Under Executive Order 12630

    Pursuant to Executive Order 12630, ``Governmental Actions and 
Interference with Constitutionally Protected Property Rights,'' 53 FR 
8859 (March 18, 1988), DOE has determined that this final rule will not 
result in any takings that might require compensation under the Fifth 
Amendment to the U.S. Constitution.

J. Review Under the Treasury and General Government Appropriations Act, 
2001

    Section 515 of the Treasury and General Government Appropriations 
Act, 2001 (44 U.S.C. 3516 note) provides for Federal agencies to review 
most disseminations of information to the public under information 
quality guidelines established by each agency pursuant to general 
guidelines issued by OMB. OMB's guidelines were published at 67 FR 8452 
(Feb. 22, 2002), and DOE's guidelines were published at 67 FR 62446 
(Oct. 7, 2002). DOE has reviewed this final rule under the OMB and DOE 
guidelines and has concluded that it is consistent with the applicable 
policies in those guidelines.

K. Review Under Executive Order 13211

    Executive Order 13211, ``Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use,'' 66 FR 28355 
(May 22, 2001), requires Federal agencies to prepare and submit to OIRA 
at OMB, a Statement of Energy Effects for any significant energy 
action. A ``significant energy action'' is defined as any action by an 
agency that promulgates or is expected to lead to promulgation of a 
final rule, and that: (1) Is a significant regulatory action under 
Executive Order 12866, or any successor order; and (2) is likely to 
have a significant adverse effect on the supply, distribution, or use 
of energy; or (3) is designated by the Administrator of OIRA as a 
significant energy action. For any significant energy action, the 
agency must give a detailed statement of any adverse effects on energy 
supply, distribution, or use if the regulation is implemented, and of 
reasonable alternatives to the action and their expected benefits on 
energy supply, distribution, and use.
    DOE has concluded that the regulatory action in this document, 
which adopts amendments to the test procedure for commercial water 
heating equipment, is not a significant regulatory action under 
Executive Order 12866. Moreover, it would not have a significant 
adverse effect on the supply, distribution, or use of energy, nor has 
it been designated as a significant energy action by the Administrator 
of OIRA.

[[Page 79318]]

Accordingly, DOE has not prepared a Statement of Energy Effects for 
this final rule.

L. Review Under Section 32 of the Federal Energy Administration Act of 
1974

    Under section 301 of the Department of Energy Organization Act 
(Pub. L. 95-91; 42 U.S.C. 7101 et seq.), DOE must comply with all laws 
applicable to the former Federal Energy Administration, including 
section 32 of the Federal Energy Administration Act of 1974 (Pub. L. 
93-275), as amended by the Federal Energy Administration Authorization 
Act of 1977 (Pub. L. 95-70). (15 U.S.C. 788; FEAA) Section 32 
essentially provides in relevant part that, where a proposed rule 
authorizes or requires use of commercial standards, the notice of 
proposed rulemaking must inform the public of the use and background of 
such standards. In addition, section 32(c) requires DOE to consult with 
the Attorney General and the Chairwoman of the Federal Trade Commission 
(FTC) concerning the impact of the commercial or industry standards on 
competition.
    This final rule incorporates testing methods contained in certain 
sections, figures, and tables in the following commercial standards: 
(1) ANSI Z21.10.3-2015/CSA 4.3-2015, ``Gas-fired Water Heaters, Volume 
III, Storage Water Heaters with Input Ratings Above 75,000 Btu Per 
Hour, Circulating and Instantaneous''; (2) ANSI/ASHRAE Standard 118.1-
2012, ``Method of Testing for Rating Commercial Gas, Electric, and Oil 
Service Water-Heating Equipment''; (3) ASTM D2156-09, ``Standard Test 
Method for Smoke Density in Flue Gases from Burning Distillate Fuels''; 
(4) ASTM C177-13, ``Standard Test Method for Steady-State Heat Flux 
Measurements and Thermal Transmission Properties by Means of the 
Guarded-Hot-Plate Apparatus''; and (5) ASTM C518-15, ``Standard Test 
Method for Steady-State Thermal Transmission Properties by Means of the 
Heat Flow Meter Apparatus.'' While the amended test procedures are not 
exclusively based on these standards, DOE's amended test procedures 
adopt several provisions from these standards without amendment. The 
Department has evaluated these standards and is unable to conclude 
whether they fully comply with the requirements of section 32(b) of the 
FEAA, (i.e., that they were developed in a manner that fully provides 
for public participation, comment, and review). DOE has consulted with 
both the Attorney General and the Chairwoman of the FTC concerning the 
impact of these test procedures on competition and has received no 
comments objecting to their use.

M. Congressional Notification

    As required by 5 U.S.C. 801, DOE will report to Congress on the 
promulgation of this final rule before its effective date. The report 
will state that it has been determined that the rule is not a ``major 
rule'' as defined by 5 U.S.C. 804(2).

N. Description of Materials Incorporated by Reference

    In this final rule, DOE incorporates by reference the following 
test standards:
    (1) ANSI Z21.10.3-2015/CSA 4.3-2015, ``Gas-fired Water Heaters, 
Volume III, Storage Water Heaters with Input Ratings Above 75,000 Btu 
Per Hour, Circulating and Instantaneous,'' Annex E (normative) 
Efficiency test procedures, E.1 ``Method of test for measuring thermal 
efficiency'';
    (2) ANSI/ASHRAE Standard 118.1-2012, ``Method of Testing for Rating 
Commercial Gas, Electric, and Oil Service Water-Heating Equipment,'' 
Section 3 ``Definition and Symbols,'' Section 4 ``Classifications by 
Mode of Operation,'' Section 6 ``Instruments,'' Section 7 
``Apparatus,'' Section 8 ``Methods of Testing,'' Section 9.1.1 ``Full 
Input Rating'', and Section 10.3.1 ``Type IV and Type V Full-Capacity 
Test Method'';
    (3) ASTM C177-13, ``Standard Test Method for Steady-State Heat Flux 
Measurements and Thermal Transmission Properties by Means of the 
Guarded-Hot-Plate Apparatus''; and
    (4) ASTM C518-15, ``Standard Test Method for Steady-State Thermal 
Transmission Properties by Means of the Heat Flow Meter Apparatus.''
    (5) ASTM D2156-09, ``Standard Test Method for Smoke Density in Flue 
Gases from Burning Distillate Fuels'';
    ANSI Z21.10.3-2015/CSA 4.3-2015 is an industry-accepted test 
procedure for measuring the performance of commercial water heaters. In 
this final rule, DOE incorporates by reference sections of this test 
procedure that address test set-up, instrumentation, test conditions, 
and test conduct. ANSI Z21.10.3-2015/CSA 4.3-2015 is available on 
ANSI's Web site at http://webstore.ansi.org/RecordDetail.aspx?sku=ANSI+Z21.10.3-2015%2fCSA+4.3-2015.
    ANSI/ASHRAE Standard 118.1-2012 is an industry-accepted test 
procedure for measuring the performance of commercial water heaters. 
ANSI/ASHRAE 118.1-2012 is available on ANSI's Web site at http://webstore.ansi.org/RecordDetail.aspx?sku=ANSI%2FASHRAE+Standard+118.1-2012.
    ASTM C177-13 is an industry-accepted test procedure for determining 
the R-value of a sample using a guarded-hot-plate apparatus. ASTM C177-
13 is available on ASTM's Web site at http://www.astm.org/Standards/C177.htm.
    ASTM C518-15 is an industry-accepted test procedure for determining 
the R-value of a sample using a heat flow meter apparatus. ASTM C518-15 
is available on ASTM's Web site at http://www.astm.org/Standards/C518.htm.
    ASTM D2156-09 is an industry-accepted test procedure for 
determining the smoke spot number of flue gases. ASTM D2156-09 is 
available on ASTM's Web site at http://www.astm.org/Standards/D2156.htm.

V. Approval of the Office of the Secretary

    The Secretary of Energy has approved publication of this final 
rule.

List of Subjects

10 CFR Part 429

    Confidential business information, Energy conservation, Household 
appliances, Imports, Reporting and recordkeeping requirements.

10 CFR Part 430

    Administrative practice and procedure, Confidential business 
information, Energy conservation, Household appliances, Imports, 
Intergovernmental relations, Small businesses.

10 CFR Part 431

    Administrative practice and procedure, Confidential business 
information, Incorporation by reference, Test procedures, Reporting and 
recordkeeping requirements.

    Issued in Washington, DC, on October 21, 2016.
Kathleen B. Hogan,
Deputy Assistant Secretary for Energy Efficiency, Energy Efficiency and 
Renewable Energy.
    For the reasons set forth in the preamble, DOE amends parts 429, 
430, and 431 of chapter II, subchapter D of title 10, Code of Federal 
Regulations, as set forth below:

PART 429--CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR CONSUMER 
PRODUCTS AND COMMERCIAL AND INDUSTRIAL EQUIPMENT

0
1. The authority citation for part 429 continues to read as follows:

    Authority: 42 U.S.C. 6291-6317; 28 U.S.C. 2461 note.


0
2. Section 429.44 is amended by:

[[Page 79319]]

0
a. Revising paragraphs (b) and (c);
0
b. Redesignating paragraph (d) as (e) and revising newly redesignated 
paragraph (e); and
0
c. Adding a reserved paragraph (d).
    The revisions read as follows:


Sec.  429.44   Commercial water heating equipment.

* * * * *
    (b) Determination of represented values for all types of commercial 
water heaters except residential-duty commercial water heaters. 
Manufacturers must determine the represented values, which includes the 
certified ratings, for each basic model of commercial water heating 
equipment except residential-duty commercial water heaters, either by 
testing, in conjunction with the applicable sampling provisions, or by 
applying an AEDM as set forth in Sec.  429.70.
    (1) Units to be tested. If the represented value for a given basic 
model is determined through testing:
    (i) The general requirements of Sec.  429.11 apply; and
    (ii) A sample of sufficient size must be randomly selected and 
tested to ensure that:
    (A) Any represented value of energy consumption or other measure of 
energy use of a basic model for which consumers would favor lower 
values must be greater than or equal to the higher of:
    (1) The mean of the sample, where:
    [GRAPHIC] [TIFF OMITTED] TR10NO16.008
    
    And, x is the sample mean; n is the number of samples; and 
xi is the ith sample; or,
    (2) The upper 95-percent confidence limit (UCL) of the true mean 
divided by 1.05, where:
[GRAPHIC] [TIFF OMITTED] TR10NO16.009

    And x is the sample mean; s is the sample standard deviation; n is 
the number of samples; and t0.95 is the t statistic for a 
95-percent one-tailed confidence interval with n-1 degrees of freedom 
(from appendix A to subpart B of this part). And,
    (B) Any represented value of energy efficiency or other measure of 
energy consumption of a basic model for which consumers would favor 
higher values must be less than or equal to the lower of:
    (1) The mean of the sample, where:
    [GRAPHIC] [TIFF OMITTED] TR10NO16.010
    
    And, x is the sample mean; n is the number of samples; and 
xi is the ith sample; or,
    (2) The lower 95-percent confidence limit (LCL) of the true mean 
divided by 0.95, where:
[GRAPHIC] [TIFF OMITTED] TR10NO16.011

    And x is the sample mean; s is the sample standard deviation; n is 
the number of samples; and t0.95 is the t statistic for a 
95-percent one-tailed confidence interval with n-1 degrees of freedom 
(from appendix A to subpart B of this part).
    (2) Alternative efficiency determination methods. In lieu of 
testing, a represented value of efficiency or consumption for a basic 
model must be determined through the application of an AEDM pursuant to 
the requirements of Sec.  429.70 and the provisions of this section, 
where:
    (i) Any represented value of energy consumption or other measure of 
energy use of a basic model for which consumers would favor lower 
values must be greater than or equal to the output of the AEDM and less 
than or equal to the Federal standard for that basic model; and
    (ii) Any represented value of energy efficiency or other measure of 
energy consumption of a basic model for which consumers would favor 
higher values must be less than or equal to the output of the AEDM and 
greater than or equal to the Federal standard for that basic model.
    (3) Rated input. The rated input for a basic model reported in 
accordance with paragraph (c)(2) of this section must be the maximum 
rated input listed on the nameplate for that basic model.
    (c) Certification reports. For commercial water heating equipment 
other than residential-duty commercial water heaters:
    (1) The requirements of Sec.  429.12 apply; and
    (2) Pursuant to Sec.  429.12(b)(13), a certification report must 
include the following public equipment-specific information:
    (i) Commercial electric storage water heaters with storage capacity 
less than or equal to 140 gallons: The standby loss in percent per hour 
(%/h) and the measured storage volume in gallons (gal).
    (ii) Commercial gas-fired and oil-fired storage water heaters with 
storage capacity less than or equal to 140 gallons: The thermal 
efficiency in percent (%), the standby loss in British thermal units 
per hour (Btu/h), the rated storage volume in gallons (gal), and the 
rated input in British thermal units per hour (Btu/h).
    (iii) Commercial water heaters and hot water supply boilers with 
storage capacity greater than 140 gallons: The thermal efficiency in 
percent (%); whether the storage volume is greater than 140 gallons 
(Yes/No); whether the tank surface area is insulated with at least R-
12.5 (Yes/No); whether a standing pilot light is used (Yes/No); for gas 
or oil-fired water heaters, whether the basic model has a fire damper 
or fan-assisted combustion (Yes/No); and, if applicable, pursuant to 
Sec.  431.110 of this chapter, the standby loss in British thermal 
units per hour (Btu/h); the measured storage volume in gallons (gal); 
and the rated input in British thermal units per hour (Btu/h).
    (iv) Commercial gas-fired and oil-fired instantaneous water heaters 
with storage capacity greater than or equal to 10 gallons and gas-fired 
and oil-fired hot water supply boilers with storage capacity greater 
than or equal to 10 gallons: The thermal efficiency in percent (%); the 
standby loss in British thermal units per hour (Btu/h); the rated 
storage volume in gallons (gal); the rated input in British thermal 
units per hour (Btu/h); whether the water heater includes a storage 
tank with a storage volume greater than or equal to 10 gallons (Yes/
No). For equipment that does not meet the definition of storage-type 
instantaneous water heaters (as set forth in 10 CFR 431.102), in 
addition to the requirements discussed previously in this paragraph 
(c)(2)(iv), the following must also be included in the certification 
report: whether the measured storage volume is determined using weight-
based test in accordance with Sec.  431.106 of this chapter or the 
calculation-based method in accordance with Sec.  429.72; whether the 
water heater will initiate main burner operation based on a 
temperature-controlled call for heating that is internal to the water 
heater (Yes/No); whether the water heater is equipped with an integral 
pump purge functionality (Yes/No); if the water heater is equipped with 
integral pump purge, the default duration of the pump off delay 
(minutes).
    (v) Commercial gas-fired and oil-fired instantaneous water heaters 
with storage capacity less than 10 gallons and gas-fired and oil-fired 
hot water supply boilers with storage capacity less than 10 gallons: 
The thermal efficiency in percent (%); the rated storage volume in 
gallons (gal), the rated input in British

[[Page 79320]]

thermal units per hour (Btu/h); and whether the measured storage volume 
is determined using weight-based test in accordance with Sec.  431.106 
of this chapter or the calculation-based method in accordance with 
Sec.  429.72.
    (vi) Commercial unfired hot water storage tanks: The thermal 
insulation (i.e., R-value) and stored volume in gallons (gal).
    (3) Pursuant to Sec.  429.12(b)(13), a certification report must 
include the following additional, equipment-specific information:
    (i) Whether the basic model is engineered-to-order; and
    (ii) For any basic model rated with an AEDM, whether the 
manufacturer elects the witness test option for verification testing. 
(See Sec.  429.70(c)(5)(iii) for options.) However, the manufacturer 
may not select more than 10 percent of AEDM-rated basic models to be 
eligible for witness testing.
    (4) Pursuant to Sec.  429.12(b)(13), a certification report may 
include supplemental testing instructions in PDF format. If necessary 
to run a valid test, the equipment-specific, supplemental information 
must include any additional testing and testing set-up instructions 
(e.g., whether a bypass loop was used for testing) for the basic model 
and all other information (e.g., operational codes or overrides for the 
control settings) necessary to operate the basic model under the 
required conditions specified by the relevant test procedure. A 
manufacturer may also include with a certification report other 
supplementary items in PDF format for DOE's consideration in performing 
testing under subpart C of this part. For example, for oil-fired 
commercial water heating equipment (other than residential-duty 
commercial water heaters): The allowable range for CO2 
reading in percent (%) and the fuel pump pressure in pounds per square 
inch gauge (psig).
* * * * *
    (e) Alternative methods for determining efficiency or energy use 
for commercial water heating equipment can be found in Sec.  429.70 of 
this subpart.

0
3. Section 429.72 is amended by adding paragraph (e) to read as 
follows:


Sec.  429.72  Alternative methods for determining non-energy ratings.

* * * * *
    (e) Commercial gas-fired and oil-fired instantaneous water heaters 
and hot water supply boilers. The storage volume of a commercial gas-
fired or oil-fired instantaneous water heater or a commercial gas-fired 
or oil-fired hot water supply boiler basic model may be determined by 
performing a calculation of the stored water volume based upon design 
drawings (including computer-aided design (CAD) models) or physical 
dimensions of the basic model. Any value of storage volume of a basic 
model reported to DOE in a certification of compliance in accordance 
with Sec.  429.44(c)(2)(iv) and (v) must be calculated using the design 
drawings or physical dimensions, or measured as per the applicable 
provisions in the test procedures in 10 CFR 431.106. The storage volume 
determination must include all water contained within the water heater 
from the inlet connection to the outlet connection(s). The storage 
volume of water contained in the water heater must then be computed in 
gallons.

0
4. Section 429.134 is amended by adding paragraph (n) to read as 
follows:


Sec.  429.134  Product-specific enforcement provisions.

* * * * *
    (n) Commercial water heating equipment other than residential-duty 
commercial water heaters--(1) Verification of fuel input rate. The fuel 
input rate of each tested unit of the basic model will be measured 
pursuant to the test requirements of Sec.  431.106 of this chapter. The 
measured fuel input rate (either the measured fuel input rate for a 
single unit sample or the average of the measured fuel input rates for 
a multiple unit sample) will be compared to the rated input certified 
by the manufacturer. The certified rated input will be considered valid 
only if the measured fuel input rate is within two percent of the 
certified rated input.
    (i) If the certified rated input is found to be valid, then the 
certified rated input will serve as the basis for determination of the 
appropriate equipment class and calculation of the standby loss 
standard (as applicable).
    (ii) If the measured fuel input rate for gas-fired commercial water 
heating equipment is not within two percent of the certified rated 
input, DOE will first attempt to increase or decrease the gas outlet 
pressure within 10 percent of the value specified on the nameplate of 
the model of commercial water heating equipment being tested to achieve 
the certified rated input (within 2 percent). If the fuel input rate is 
still not within two percent of the certified rated input, DOE will 
attempt to increase or decrease the gas supply pressure within the 
range specified on the nameplate of the model of commercial water 
heating equipment being tested. If the measured fuel input rate is 
still not within two percent of the certified rated input, DOE will 
attempt to modify the gas inlet orifice, if the unit is equipped with 
one. If the measured fuel input rate still is not within two percent of 
the certified rated input, the measured fuel input rate will serve as 
the basis for determination of the appropriate equipment class and 
calculation of the standby loss standard (as applicable).
    (iii) If the measured fuel input rate for oil-fired commercial 
water heating equipment is not within two percent of the certified 
rated input, the measured fuel input rate will serve as the basis for 
determination of the appropriate equipment class and calculation of the 
standby loss standard (as applicable).
    (2) [Reserved]

PART 430--ENERGY CONSERVATION PROGRAM FOR CONSUMER PRODUCTS

0
5. The authority citation for part 430 continues to read as follows:

    Authority:  42 U.S.C. 6291-6309; 28 U.S.C. 2461 note.


0
6. Section 430.2 is amended by:
0
a. Removing the definition of ``Electric heat pump water heater'';
0
b. Revising the definitions of ``Electric instantaneous water heater'' 
and ``Electric storage water heater'';
0
c. Removing the definition of ``Gas-fired heat pump water heater''; and
0
 d. Revising the definitions of ``Gas-fired instantaneous water 
heater'', ``Gas-fired storage water heater'', ``Oil-fired instantaneous 
water heater'', and ``Oil-fired storage water heater''.
    The revisions read as follows:


Sec.  430.2   Definitions.

* * * * *
    Electric instantaneous water heater means a water heater that uses 
electricity as the energy source, has a nameplate input rating of 12 kW 
or less, and contains no more than one gallon of water per 4,000 Btu 
per hour of input.
* * * * *
    Electric storage water heater means a water heater that uses 
electricity as the energy source, has a nameplate input rating of 12 kW 
or less, and contains more than one gallon of water per 4,000 Btu per 
hour of input.
* * * * *
    Gas-fired instantaneous water heater means a water heater that uses 
gas as the main energy source, has a nameplate input rating less than 
200,000 Btu/h, and contains no more than one gallon of water per 4,000 
Btu per hour of input.
    Gas-fired storage water heater means a water heater that uses gas 
as the main energy source, has a nameplate input rating of 75,000 Btu/h 
or less, and contains more than one gallon of water per 4,000 Btu per 
hour of input.
* * * * *

[[Page 79321]]

    Oil-fired instantaneous water heater means a water heater that uses 
oil as the main energy source, has a nameplate input rating of 210,000 
Btu/h or less, and contains no more than one gallon of water per 4,000 
Btu per hour of input.
    Oil-fired storage water heater means a water heater that uses oil 
as the main energy source, has a nameplate input rating of 105,000 Btu/
h or less, and contains more than one gallon of water per 4,000 Btu per 
hour of input.
* * * * *

PART 431--ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND 
INDUSTRIAL EQUIPMENT

0
7. The authority citation for part 431 continues to read as follows:

     Authority:  42 U.S.C. 6291-6317; 28 U.S.C. 2461 note.


0
8. Section 431.102 is amended by:
0
a. Revising the section heading;
0
b. Adding in alphabetical order a definition for ``Air-source 
commercial heat pump water heater;''
0
c. Removing the definition of ``ASTM-D-2156-80;''
0
d. Adding in alphabetical order definitions for ``Coefficient of 
performance,'' ``Commercial heat pump water heater,'' ``Direct geo-
exchange commercial heat pump water heater,'' ``Flow-activated 
instantaneous water heater,'' ``Fuel input rate,'' ``Ground-source 
closed-loop commercial heat pump water heater,'' and ``Ground water-
source commercial heat pump water heater;''
0
e. Revising the definition of ``Hot water supply boiler;''
0
f. Adding in alphabetical order a definition for ``Indoor water-source 
commercial heat pump water heater;''
0
g. Revising the definition of ``Instantaneous water heater;''
0
h. Removing the definition of ``Packaged boiler;''
0
i. Adding in alphabetical order a definition for ``Rated input;''
0
j. Revising the definitions of ``R-value,'' ``Residential-duty 
commercial water heater,'' and ``Standby loss,''
0
k. Adding in alphabetical order a definition for ``Storage-type 
instantaneous water heater;''
    and
0
l. Revising the definition of ``Storage water heater.''
    The revisions and additions read as follows:


Sec.  431.102   Definitions concerning commercial water heaters, hot 
water supply boilers, unfired hot water storage tanks, and commercial 
heat pump water heaters.

    Air-source commercial heat pump water heater means a commercial 
heat pump water heater that utilizes indoor or outdoor air as the heat 
source.
* * * * *
    Coefficient of performance (COPh) means the 
dimensionless ratio of the rate of useful heat transfer gained by the 
water (expressed in Btu/h), to the rate of electric power consumed 
during operation (expressed in Btu/h).
    Commercial heat pump water heater (CHPWH) means a water heater 
(including all ancillary equipment such as fans, blowers, pumps, 
storage tanks, piping, and controls, as applicable) that uses a 
refrigeration cycle, such as vapor compression, to transfer heat from a 
low-temperature source to a higher-temperature sink for the purpose of 
heating potable water, and has a rated electric power input greater 
than 12 kW. Such equipment includes, but is not limited to, air-source 
heat pump water heaters, water-source heat pump water heaters, and 
direct geo-exchange heat pump water heaters.
    Direct geo-exchange commercial heat pump water heater means a 
commercial heat pump water heater that utilizes the earth as a heat 
source and allows for direct exchange of heat between the earth and the 
refrigerant in the evaporator coils.
    Flow-activated instantaneous water heater means an instantaneous 
water heater or hot water supply boiler that activates the burner or 
heating element only if heated water is drawn from the unit.
    Fuel input rate means the maximum measured rate at which gas-fired 
or oil-fired commercial water heating equipment uses energy as 
determined using test procedures prescribed under Sec.  431.106 of this 
part.
    Ground-source closed-loop commercial heat pump water heater means a 
commercial heat pump water heater that utilizes a fluid circulated 
through a closed piping loop as a medium to transfer heat from the 
ground to the refrigerant in the evaporator. The piping loop may be 
buried inside the ground in horizontal trenches or vertical bores, or 
submerged in a surface water body.
    Ground water-source commercial heat pump water heater means a 
commercial heat pump water heater that utilizes ground water as the 
heat source.
    Hot water supply boiler means a packaged boiler (defined in Sec.  
431.82 of this part) that is industrial equipment and that:
    (1) Has a rated input from 300,000 Btu/h to 12,500,000 Btu/h and of 
at least 4,000 Btu/h per gallon of stored water;
    (2) Is suitable for heating potable water; and
    (3) Meets either or both of the following conditions:
    (i) It has the temperature and pressure controls necessary for 
heating potable water for purposes other than space heating; or
    (ii) The manufacturer's product literature, product markings, 
product marketing, or product installation and operation instructions 
indicate that the boiler's intended uses include heating potable water 
for purposes other than space heating.
    Indoor water-source commercial heat pump water heater means a 
commercial heat pump water heater that utilizes indoor water as the 
heat source.
    Instantaneous water heater means a water heater that uses gas, oil, 
or electricity, including:
    (1) Gas-fired instantaneous water heaters with a rated input both 
greater than 200,000 Btu/h and not less than 4,000 Btu/h per gallon of 
stored water;
    (2) Oil-fired instantaneous water heaters with a rated input both 
greater than 210,000 Btu/h and not less than 4,000 Btu/h per gallon of 
stored water; and
    (3) Electric instantaneous water heaters with a rated input both 
greater than 12 kW and not less than 4,000 Btu/h per gallon of stored 
water.
* * * * *
    Rated input means the maximum rate at which commercial water 
heating equipment is rated to use energy as specified on the nameplate.
    R-value means the thermal resistance of insulating material as 
determined using ASTM C177-13 or C518-15 (incorporated by reference; 
see Sec.  431.105) and expressed in ([deg]F[middot]ft\2\[middot]h/Btu).
    Residential-duty commercial water heater means any gas-fired 
storage, oil-fired storage, or electric instantaneous commercial water 
heater that meets the following conditions:
    (1) For models requiring electricity, uses single-phase external 
power supply;
    (2) Is not designed to provide outlet hot water at temperatures 
greater than 180 [deg]F; and
    (3) Does not meet any of the following criteria:

[[Page 79322]]



------------------------------------------------------------------------
                                            Indicator of non-residential
             Water heater type                       application
------------------------------------------------------------------------
Gas-fired Storage.........................  Rated input >105 kBtu/h;
                                             Rated storage volume >120
                                             gallons.
Oil-fired Storage.........................  Rated input >140 kBtu/h;
                                             Rated storage volume >120
                                             gallons.
Electric Instantaneous....................  Rated input >58.6 kW; Rated
                                             storage volume >2 gallons.
------------------------------------------------------------------------

    Standby loss means:
    (1) For electric commercial water heating equipment (not including 
commercial heat pump water heaters), the average hourly energy required 
to maintain the stored water temperature expressed as a percent per 
hour (%/h) of the heat content of the stored water above room 
temperature and determined in accordance with appendix B or D to 
subpart G of part 431 (as applicable), denoted by the term ``S''; or
    (2) For gas-fired and oil-fired commercial water heating equipment, 
the average hourly energy required to maintain the stored water 
temperature expressed in British thermal units per hour (Btu/h) based 
on a 70[emsp14][deg]F temperature differential between stored water and 
ambient room temperature and determined in accordance with appendix A 
or C to subpart G of part 431 (as applicable), denoted by the term 
``SL.''
    Storage-type instantaneous water heater means an instantaneous 
water heater that includes a storage tank with a storage volume greater 
than or equal to 10 gallons.
    Storage water heater means a water heater that uses gas, oil, or 
electricity to heat and store water within the appliance at a 
thermostatically-controlled temperature for delivery on demand, 
including:
    (1) Gas-fired storage water heaters with a rated input both greater 
than 75,000 Btu/h and less than 4,000 Btu/h per gallon of stored water;
    (2) Oil-fired storage water heaters with a rated input both greater 
than 105,000 Btu/h and less than 4,000 Btu/h per gallon of stored 
water; and
    (3) Electric storage water heaters with a rated input both greater 
than 12 kW and less than 4,000 Btu/h per gallon of stored water.
* * * * *


Sec.  431.104   [Removed]

0
9. Section 431.104 is removed.

0
10. Section 431.105 is amended by revising paragraph (b) and adding 
paragraphs (c) and (d) to read as follows:


Sec.  431.105  Materials incorporated by reference.

* * * * *
    (b) ASHRAE. American Society of Heating, Refrigerating and Air-
Conditioning Engineers, 1791 Tullie Circle NE. Atlanta, GA 30329, (800) 
527-4723, or go to https://www.ashrae.org.
    (1) ANSI/ASHRAE Standard 118.1-2012, ``Method of Testing for Rating 
Commercial Gas, Electric, and Oil Service Water-Heating Equipment,'' 
approved by ASHRAE on October 26, 2012, IBR approved for appendix E to 
this subpart, as follows:
    (i) Section 3--Definitions and Symbols;
    (ii) Section 4--Classifications by Mode of Operation (sections 4.4, 
and 4.5 only);
    (iii) Section 6--Instruments (except sections 6.3, 6.4 and 6.6);
    (iv) Section 7--Apparatus (except section 7.4, Figures 1 through 4, 
section 7.7.5, Table 2, and section 7.7.7.4);
    (v) Section 8--Methods of Testing:
    (A) Section 8.2--Energy Supply, Section 8.2.1--Electrical Supply;
    (B) Section 8.7--Water Temperature Control;
    (vi) Section 9--Test Procedures: 9.1--Input Rating, Heating 
Capacity, Thermal Efficiency, Coefficient of Performance (COP), and 
Recovery Rating; 9.1.1--Full Input Rating;
    (vii) Section 10--Calculation of Results: Section 10.3--Heat-Pump 
Water Heater Water-Heating Capacity, Coefficient of Performance (COP), 
and Recovery Rating; Section 10.3.1--Type IV and Type V Full-Capacity 
Test Method.
    (2) [Reserved]
    (c) ASTM. ASTM International, 100 Barr Harbor Drive, P.O. Box C700, 
West Conshohocken, PA 19428-2959, (610) 832-9585, or go to http://www.astm.org.
    (1) ASTM C177-13, ``Standard Test Method for Steady-State Heat Flux 
Measurements and Thermal Transmission Properties by Means of the 
Guarded-Hot-Plate Apparatus,'' approved September 15, 2013, IBR 
approved for Sec.  431.102.
    (2) ASTM C518-15, ``Standard Test Method for Steady-State Thermal 
Transmission Properties by Means of the Heat Flow Meter Apparatus,'' 
approved September 1, 2015, IBR approved for Sec.  431.102t.
    (3) ASTM D2156-09 (Reapproved 2013), ``Standard Test Method for 
Smoke Density in Flue Gases from Burning Distillate Fuels,'' approved 
October 1, 2013, IBR approved for appendices A and C to this subpart.
    (d) CSA Group, 5060 Spectrum Way, Suite 100, Mississauga, Ontario, 
Canada L4W 5N6, 800-463-6727, or go to http://www.csagroup.org/.
    (1) ANSI Z21.10.3-2015 * CSA 4.3-2015 (``ANSI Z21.10.3-2015''), 
``Gas-fired water heaters, volume III, storage water heaters with input 
ratings above 75,000 Btu per hour, circulating and instantaneous,'' 
approved by ANSI on October 5, 2015, IBR approved for appendices A, B, 
and C to this subpart, as follows:
    (i) Annex E (normative) Efficiency test procedures--E.1--Method of 
test for measuring thermal efficiency, paragraph c--Vent requirements; 
and
    (ii) Annex E (normative) Efficiency test procedures--E.1--Method of 
test for measuring thermal efficiency, paragraph f--Installation of 
temperature sensing means.
    (2) [Reserved]

0
11. Section 431.106 is revised to read as follows:


Sec.  431.106  Uniform test method for the measurement of energy 
efficiency of commercial water heating equipment.

    (a) Scope. This section contains test procedures for measuring, 
pursuant to EPCA, the energy efficiency of commercial water heating 
equipment.
    (b) Testing and calculations. Determine the energy efficiency of 
commercial water heating equipment by conducting the applicable test 
procedure(s):
    (1) Residential-duty commercial water heaters. Test in accordance 
with appendix E to subpart B of part 430 of this chapter.
    (2) Commercial water heating equipment other than residential-duty 
commercial water heaters. Test in accordance with the appropriate test 
procedures in appendices to subpart G of this part.
    (i) Gas-fired and oil-fired storage water heaters and storage-type 
instantaneous water heaters. Test according to appendix A to subpart G 
of this part.
    (ii) Electric storage water heaters and storage-type instantaneous 
water heaters. Test according to appendix B to subpart G of this part.
    (iii) Gas-fired and oil-fired instantaneous water heaters and hot 
water supply boilers (other than storage-type instantaneous water 
heaters). Test

[[Page 79323]]

according to appendix C to subpart G of this part.
    (iv) Electric instantaneous water heaters (other than storage-type 
instantaneous water heaters). Test according to appendix D to subpart G 
of this part.
    (v) Commercial heat pump water heaters. Test according to appendix 
E to subpart G of this part.


Sec.  431.107   [Removed]

0
12. Section 431.107 is removed.

0
13. Add appendix A to subpart G of part 431 to read as follows:

Appendix A to Subpart G of Part 431--Uniform Test Method for the 
Measurement of Thermal Efficiency and Standby Loss of Gas-Fired and 
Oil-Fired Storage Water Heaters and Storage-Type Instantaneous Water 
Heaters

    Note: Prior to November 6, 2017, manufacturers must make any 
representations with respect to the energy use or efficiency of the 
subject commercial water heating equipment in accordance with the 
results of testing pursuant to this appendix or the procedures in 10 
CFR 431.106 that were in place on January 1, 2016. On and after 
November 6, 2017, manufacturers must make any representations with 
respect to energy use or efficiency of gas-fired and oil-fired storage 
water heaters and storage-type instantaneous water heaters in 
accordance with the results of testing pursuant to this appendix to 
demonstrate compliance with the energy conservation standards at 10 CFR 
431.110.

1. General

    Determine the thermal efficiency and standby loss (as applicable) 
in accordance with the following sections of this appendix. Certain 
sections reference sections of Annex E.1 of ANSI Z21.10.3-2015 
(incorporated by reference; see Sec.  431.105). Where the instructions 
contained in the sections below conflict with instructions in Annex E.1 
of ANSI Z21.10.3-2015, the instructions contained in this appendix 
control.

2. Test Set-Up

    2.1. Placement of Water Heater. A water heater for installation on 
combustible floors must be placed on a \3/4\-inch plywood platform 
supported by three 2 x 4-inch runners. If the water heater is for 
installation on noncombustible floors, suitable noncombustible material 
must be placed on the platform. When the use of the platform for a 
large water heater is not practical, the water heater may be placed on 
any suitable flooring. A wall-mounted water heater must be mounted on a 
simulated wall section.
    2.2. Installation of Temperature Sensors. Inlet and outlet water 
piping must be turned vertically downward from the connections on the 
water heater so as to form heat traps. Temperature sensors for 
measuring supply and outlet water temperatures must be installed 
upstream from the inlet heat trap piping and downstream from the outlet 
heat trap piping, respectively, in accordance with Figure 2.1, 2.2, or 
2.3 (as applicable based on the location of inlet and outlet piping 
connections) of this section.
    The water heater must meet the requirements shown in Figure 2.1, 
2.2, or 2.3 (as applicable) at all times during the conduct of the 
thermal efficiency and standby loss tests. Any factory-supplied heat 
traps must be installed per the installation instructions while 
ensuring the requirements in Figure 2.1, 2.2, or 2.3 are met. All 
dimensions specified in Figure 2.1, 2.2, and 2.3 and in this section 
are measured from the outer surface of the pipes and water heater outer 
casing (as applicable).

[[Page 79324]]

[GRAPHIC] [TIFF OMITTED] TR10NO16.012


[[Page 79325]]


[GRAPHIC] [TIFF OMITTED] TR10NO16.013

    2.3 Installation of Temperature Sensors for Measurement of Mean 
Tank Temperature. Install temperature sensors inside the tank for 
measurement of mean tank temperature according to the instructions in 
paragraph f of Annex E.1 of ANSI Z21.10.3-2015 (incorporated by 
reference; see Sec.  431.105). Calculate the mean tank temperature as 
the average of the six installed temperature sensors.
    2.4. Piping Insulation. Insulate all water piping external to the 
water heater jacket, including heat traps and piping that are installed 
by the manufacturer or shipped with the unit, for at least 4 ft of 
piping length from the connection at the appliance, with material 
having an R-value not less than 4 [deg]F[middot]ft\2\[middot]h/Btu. 
Ensure that the insulation does not contact any appliance surface 
except at the location where the pipe connections penetrate the 
appliance jacket or enclosure.
    2.5. Temperature and Pressure Relief Valve Insulation. If the 
manufacturer has not provided a temperature and pressure relief valve, 
one shall be installed and insulated as specified in section 2.4 of 
this appendix.
    2.6. Vent Requirements. Follow the requirements for venting 
arrangements specified in paragraph c of Annex E.1 of ANSI Z21.10.3-
2015 (incorporated by reference; see Sec.  431.105).
    2.7. Energy Consumption. Install equipment that determines, within 
 1 percent:
    2.7.1. The quantity and rate of fuel consumed.
    2.7.2. The quantity of electricity consumed by factory-supplied 
water heater components.

3. Test Conditions

    3.1. Water Supply
    3.1.1. Water Supply Pressure. The pressure of the water supply must 
be maintained between 40 psi and the maximum pressure specified by the 
manufacturer of the unit being tested. The accuracy of the pressure-
measuring devices must be within  1.0 pounds per square 
inch (psi).
    3.1.2. Water Supply Temperature. During the steady-state 
verification period and the thermal efficiency test, the temperature of 
the supply water must be maintained at 70 [deg]F  2 [deg]F.
    3.1.3. Isolate the water heater using a shutoff valve in the supply 
line with an expansion tank installed in the supply line downstream of 
the shutoff valve. There must be no shutoff means between the expansion 
tank and the appliance inlet.
    3.2. Gas Pressure for Gas-Fired Equipment. The supply gas pressure 
must be within the range specified by the manufacturer on the nameplate 
of the unit being tested. The difference between the outlet pressure of 
the gas appliance pressure regulator and the value specified by the 
manufacturer on the nameplate of the unit being tested must not exceed 
the greater of:  10 percent of the nameplate value or 
 0.2 inches water column (in. w.c.). Obtain the higher 
heating value of the gas burned.
    3.3. Ambient Room Temperature. During the soak-in period (as 
applicable), the steady-state verification period, the thermal 
efficiency test, and the standby loss test, maintain the ambient room 
temperature at 75 [deg]F  10 [deg]F at all times. Measure 
the ambient room temperature at 1-minute intervals during these 
periods, except for the soak-in period. Measure the ambient room 
temperature once before beginning the soak-in period, and ensure no 
actions are taken during the soak-in period that would cause the 
ambient room temperature to deviate from the allowable range. Measure 
the ambient room temperature at the vertical mid-point of the water 
heater and approximately 2 feet from the water heater jacket. Shield 
the sensor against radiation. Calculate the average ambient room 
temperature separately for the thermal efficiency test and standby loss 
test. During the thermal efficiency and standby loss tests, the ambient 
room temperature must not vary by more than  5.0 [deg]F at 
any reading from the average ambient room temperature.
    3.4. Test Air Temperature. During the steady-state verification 
period, the thermal efficiency test, and the standby loss test, the 
test air temperature must not vary by more than  5 [deg]F 
from the ambient room temperature at any reading. Measure the test air 
temperature at 1-minute intervals during these periods and at a 
location within two feet of the air inlet of the water heater or the 
combustion air intake vent, as applicable. Shield the

[[Page 79326]]

sensor against radiation. For units with multiple air inlets, measure 
the test air temperature at each air inlet, and maintain the specified 
tolerance on deviation from the ambient room temperature at each air 
inlet. For units without a dedicated air inlet, measure the test air 
temperature within two feet of any location on the water heater where 
combustion air is drawn.
    3.5. Maximum Air Draft. During the steady-state verification 
period, the thermal efficiency test, and the standby loss test, the 
water heater must be located in an area protected from drafts of more 
than 50 ft/min. Prior to beginning the steady-state verification period 
and the standby loss test, measure the air draft within three feet of 
the jacket or enclosure of the water heater to ensure this condition is 
met. Ensure that no other changes that would increase the air draft are 
made to the test set-up or conditions during the conduct of the tests.
    3.6. Setting the Tank Thermostat. Before starting the steady-state 
verification period (as applicable) or before the soak-in period (as 
applicable), the thermostat setting must first be obtained by starting 
with the water in the system at 70 [deg]F  2 [deg]F. Set 
the thermostat to ensure:
    3.6.1. With the supply water temperature set as per section 3.1.2 
of this appendix (i.e., 70 [deg]F  2 [deg]F), the water 
flow rate can be varied so that the outlet water temperature is 
constant at 70 [deg]F  2 [deg]F above the supply water 
temperature while the burner is firing at full firing rate; and
    3.6.2. After the water supply is turned off and the thermostat 
reduces the fuel supply to a minimum, the maximum water temperature 
measured by the topmost tank temperature sensor (i.e., the highest of 
the 6 temperature sensors used for calculating mean tank temperature, 
as required by section 2.3 of this appendix) is 140 [deg]F  
5 [deg]F.
    3.7. Additional Requirements for Oil-Fired Equipment.
    3.7.1. Venting Requirements. Connect a vertical length of flue pipe 
to the flue gas outlet of sufficient height so as to meet the minimum 
draft specified by the manufacturer.
    3.7.2. Oil Supply. Adjust the burner rate so that the following 
conditions are met:
    3.7.2.1. The CO2 reading is within the range specified 
by the manufacturer;
    3.7.2.2. The fuel pump pressure is within  10 percent 
of manufacturer's specifications;
    3.7.2.3. If either the fuel pump pressure or range for 
CO2 reading are not specified by the manufacturer on the 
nameplate of the unit, in literature shipped with the unit, or in 
supplemental test report instructions included with a certification 
report, then a default value of 100 psig is to be used for fuel pump 
pressure, and a default range of 9-12 percent is to be used for 
CO2 reading; and
    3.7.2.4. Smoke in the flue does not exceed No. 1 smoke as measured 
by the procedure in ASTM D2156-09 (Reapproved 2013) (incorporated by 
reference, see Sec.  431.105). To determine the smoke spot number, 
connect the smoke measuring device to an open-ended tube. This tube 
must project into the flue \1/4\ to \1/2\ of the pipe diameter.
    3.7.2.5. If no settings on the water heater have been changed and 
the water heater has not been turned off since the end of a previously 
run thermal efficiency or standby loss test, measurement of the 
CO2 reading and conduct of the smoke spot test are not 
required prior to beginning a test. Otherwise, measure the 
CO2 reading and determine the smoke spot number, with the 
burner firing, before the beginning of the steady-state verification 
period prior to the thermal efficiency test, and prior to beginning the 
standby loss test.
    3.8. Data Collection Intervals. Follow the data recording intervals 
specified in the following sections.
    3.8.1. Soak-In Period. For units that require a soak-in period, 
measure the ambient room temperature, in [deg]F, prior to beginning the 
soak-in period.
    3.8.2. Steady-State Verification Period and Thermal Efficiency 
Test. For the steady-state verification period and the thermal 
efficiency test, follow the data recording intervals specified in Table 
3.1 of this appendix.

  Table 3.1--Data To Be Recorded Before and During the Steady-State Verification Period and Thermal Efficiency
                                                      Test
----------------------------------------------------------------------------------------------------------------
                                         Before steady-state
            Item recorded                verification period       Every 1 minute \a\        Every 10 minutes
----------------------------------------------------------------------------------------------------------------
Gas supply pressure, in w.c.........  X.......................
Gas outlet pressure, in w.c.........  X.......................
Barometric pressure, in Hg..........  X.......................
Fuel higher heating value, Btu/ft\3\  X.......................
 (gas) or Btu/lb (oil).
Oil pump pressure, psig (oil only)..  X.......................
CO2 reading, % (oil only)...........   X \b\..................
Oil smoke spot reading (oil only)...   X \b\..................
Air draft, ft/min...................  X.......................
Time, minutes/seconds...............  ........................  X......................
Fuel weight or volume, lb (oil) or    ........................  .......................  X \c\
 ft\3\ (gas).
Supply water temperature (TSWT),      ........................  X......................
 [deg]F.
Outlet water temperature (TOWT),      ........................  X......................
 [deg]F.
Ambient room temperature, [deg]F....  ........................  X......................
Test air temperature, [deg]F........  ........................  X......................
Water flow rate, (gpm)..............  ........................  X......................
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ These measurements are to be recorded at the start of the steady-state verification period and the end of
  the thermal efficiency test, as well as every minute during both periods.
\b\ The smoke spot test and CO2 reading are not required prior to beginning the steady-state verification period
  if no settings on the water heater have been changed and the water heater has not been turned off since the
  end of a previously-run efficiency test (i.e., thermal efficiency or standby loss).
\c\ Fuel and electricity consumption over the course of the entire thermal efficiency test must be measured and
  used in calculation of thermal efficiency.


[[Page 79327]]

    3.8.3. Standby Loss Test. For the standby loss test, follow the 
data recording intervals specified in Table 3.2 of this appendix. 
Additionally, the fuel and electricity consumption over the course of 
the entire test must be measured and used in calculation of standby 
loss.

 Table 3.2--Data To Be Recorded Before and During the Standby Loss Test
------------------------------------------------------------------------
         Item recorded               Before test      Every 1 minute \a\
------------------------------------------------------------------------
Gas supply pressure, in w.c....  X..................  ..................
Gas outlet pressure, in w.c....  X..................  ..................
Barometric pressure, in Hg.....  X..................  ..................
Fuel higher heating value, Btu/  X..................  ..................
 ft \3\ (gas) or Btu/lb (oil).
Oil pump pressure, psig (oil     X..................  ..................
 only).
CO2 reading, % (oil only)......  X \b\..............  ..................
Oil smoke spot reading (oil      X \b\..............  ..................
 only).
Air draft, ft/min..............  X..................  ..................
Time, minutes/seconds..........  ...................  X
Mean tank temperature, [deg]F..  ...................  X \c\
Ambient room temperature,        ...................  X
 [deg]F.
Test air temperature, [deg]F...  ...................  X
------------------------------------------------------------------------
Notes:
\a\ These measurements are to be recorded at the start and end of the
  test, as well as every minute during the test.
\b\ The smoke spot test and CO2 reading are not required prior to
  beginning the standby loss test if no settings on the water heater
  have been changed and the water heater has not been turned off since
  the end of a previously-run efficiency test (i.e., thermal efficiency
  or standby loss).
\c\ Mean tank temperature is calculated as the average of the 6 tank
  temperature sensors, installed per section 2.3 of this appendix.

    4. Determination of Storage Volume. Determine the storage volume by 
subtracting the tare weight, measured while the system is dry and 
empty, from the weight of the system when filled with water and 
dividing the resulting net weight of water by the density of water at 
the measured water temperature. The volume of the water contained in 
the water heater must be computed in gallons.
    5. Thermal Efficiency Test. Before beginning the steady-state 
verification period, record the applicable parameters as specified in 
section 3.8.2 of this appendix. Begin drawing water from the unit by 
opening the main supply, and adjust the water flow rate to achieve an 
outlet water temperature of 70[emsp14][deg]F  
2[emsp14][deg]F above supply water temperature. The thermal efficiency 
test shall be deemed complete when there is a continuous, one-hour-long 
period where the steady-state conditions specified in section 5.1 of 
this appendix have been met, as confirmed by consecutive readings of 
the relevant parameters recorded at 1-minute intervals (except for fuel 
input rate, which is determined at 10-minute intervals, as specified in 
section 5.4 of this appendix). During the one-hour-long period, the 
water heater must fire continuously at its full firing rate (i.e., no 
modulations or cut-outs) and no settings can be changed on the unit 
being tested at any time. The first 30 minutes of the one-hour-period 
where the steady-state conditions in section 5.1 of this appendix are 
met is the steady-state verification period. The final 30 minutes of 
the one-hour-period where the steady-state conditions in section 5.1 of 
this appendix are met is the thermal efficiency test. The last reading 
of the steady-state verification period must be the first reading of 
the thermal efficiency test (i.e., the thermal efficiency test starts 
immediately once the steady-state verification period ends).
    5.1. Steady-State Conditions. The following conditions must be met 
at consecutive readings taken at 1-minute intervals (except for fuel 
input rate, for which measurements are taken at 10-minute intervals) to 
verify the water heater has achieved steady-state operation during the 
steady-state verification period and thermal efficiency test.
    5.1.1. The water flow rate must be maintained within  
0.25 gallons per minute (gpm) of the initial reading at the start of 
the steady-state verification period;
    5.1.2. Outlet water temperature must be maintained at 70 [deg]F 
 2 [deg]F above supply water temperature;
    5.1.3. Fuel input rate must be maintained within  2 
percent of the rated input certified by the manufacturer;
    5.1.4. The supply water temperature must be maintained within 
 0.50 [deg]F of the initial reading at the start of the 
steady-state verification period; and
    5.1.5. The rise between the supply and outlet water temperatures 
must be maintained within  0.50 [deg]F of its initial value 
taken at the start of the steady-state verification period for units 
with rated input less than 500,000 Btu/h, and maintained within  1.00 [deg]F of its initial value for units with rated input 
greater than or equal to 500,000 Btu/h.
    5.2. Water Flow Measurement. Measure the total weight of water 
heated during the 30-minute thermal efficiency test with either a scale 
or a water flow meter. With either method, the error of measurement of 
weight of water heated must not exceed 1 percent of the weight of the 
total draw.
    5.3. Determination of Fuel Input Rate. During the steady-state 
verification period and the thermal efficiency test, record the fuel 
consumed at 10-minute intervals. Calculate the fuel input rate over 
each 10-minute period using the equations in section 5.4 of this 
appendix. The measured fuel input rates for these 10-minute periods 
must not vary by more than  2 percent between any two 
readings. Determine the overall fuel input rate using the fuel 
consumption for the entire duration of the thermal efficiency test.
    5.4. Fuel Input Rate Calculation. To calculate the fuel input rate, 
use the following equation:
[GRAPHIC] [TIFF OMITTED] TR10NO16.014

Where,

Q = Fuel input rate, expressed in Btu/h
Qs = Total fuel flow as metered, expressed in ft\3\ for 
gas-fired equipment and lb for oil-fired equipment
Cs = Correction applied to the heating value of a gas H, 
when it is metered at temperature and/or pressure conditions other 
than the standard conditions for which the value of H is based. Cs=1 
for oil-fired equipment.
H = Higher heating value of fuel, expressed in Btu/ft\3\ for gas-
fired equipment and Btu/lb for oil-fired equipment.
t = Duration of measurement of fuel consumption


[[Page 79328]]


    5.5. Thermal Efficiency Calculation. Thermal efficiency must be 
calculated using data from the 30-minute thermal efficiency test. 
Calculate thermal efficiency, Et, using the following 
equation:
[GRAPHIC] [TIFF OMITTED] TR10NO16.015

Where,
K = 1.004 Btu/lb[middot][deg]F, the nominal specific heat of water 
at 105 [deg]F
W = Total weight of water heated, expressed in lb
[thetas]1 = Average supply water temperature, expressed 
in [deg]F
[thetas]2 = Average outlet water temperature, expressed 
in [deg]F
Q = Total fuel flow as metered, expressed in ft\3\ for gas-fired 
equipment and lb for oil-fired equipment.
Cs = Correction applied to the heating value of a gas H, 
when it is metered at temperature and/or pressure conditions other 
than the standard conditions for which the value of H is based. 
Cs=1 for oil-fired equipment
H. = Higher heating value of the fuel, expressed in Btu/ft\3\ for 
gas-fired equipment and Btu/lb for oil-fired equipment.
Ec = Electrical consumption of the water heater and, when 
used, the test set-up recirculating pump, expressed in Btu

6. Standby Loss Test

    6.1. If no settings on the water heater have changed and the water 
heater has not been turned off since a previously run thermal 
efficiency or standby loss test, skip to section 6.3 of this appendix. 
Otherwise, conduct the soak-in period according to section 6.2 of this 
appendix.
    6.2. Soak-In Period. Conduct a soak-in period, in which the water 
heater must sit without any draws taking place for at least 12 hours. 
Begin the soak-in period after setting the tank thermostat as specified 
in section 3.6 of this appendix, and maintain these thermostat settings 
throughout the soak-in period.
    6.3. Begin the standby loss test at the first cut-out following the 
end of the soak-in period (if applicable); or at a cut-out following 
the previous thermal efficiency or standby loss test (if applicable). 
Allow the water heater to remain in standby mode. Do not change any 
settings on the water heater at any point until measurements for the 
standby loss test are finished. Begin recording the applicable 
parameters specified in section 3.8.3 of this appendix.
    6.4. At the second cut-out, record the time and ambient room 
temperature, and begin measuring the fuel and electricity consumption. 
Record the initial mean tank temperature and initial ambient room 
temperature. For the remainder of the test, continue recording the 
applicable parameters specified in section 3.8.3 of this appendix.
    6.5. Stop the test after the first cut-out that occurs after 24 
hours, or at 48 hours, whichever comes first.
    6.6. Immediately after conclusion of the standby loss test, record 
the total fuel flow and electrical energy consumption, the final 
ambient room temperature, the duration of the standby loss test, and if 
the test ends at 48 hours without a cut-out, the final mean tank 
temperature, or if the test ends after a cut-out, the maximum mean tank 
temperature that occurs after the cut-out. Calculate the average of the 
recorded values of the mean tank temperature and of the ambient room 
temperature taken at each measurement interval, including the initial 
and final values.
    6.7. Standby Loss Calculation. To calculate the standby loss, 
follow the steps below:
    6.7.1. The standby loss expressed as a percentage (per hour) of the 
heat content of the stored water above room temperature must be 
calculated using the following equation:
[GRAPHIC] [TIFF OMITTED] TR10NO16.016

Where,
[Delta]T3 = Average value of the mean tank temperature 
minus the average value of the ambient room temperature, expressed 
in [deg]F
[Delta]T4 = Final mean tank temperature measured at the 
end of the test minus the initial mean tank temperature measured at 
the start of the test , expressed in [deg]F
k = 8.25 Btu/gallon[middot][deg]F, the nominal specific heat of 
water
Va = Volume of water contained in the water heater in 
gallons measured in accordance with section 4 of this appendix
Et = Thermal efficiency of the water heater determined in 
accordance with this appendix, expressed in %
Ec = Electrical energy consumed by the water heater 
during the duration of the test in Btu
t = Total duration of the test in hours
Cs = Correction applied to the heating value of a gas H, 
when it is metered at temperature and/or pressure conditions other 
than the standard conditions for which the value of H is based. 
Cs=1 for oil-fired equipment.
Qs = Total fuel flow as metered, expressed in ft\3\ (gas) 
or lb (oil)
H = Higher heating value of fuel, expressed in Btu/ft\3\ (gas) or 
Btu/lb (oil)
S = Standby loss, the average hourly energy required to maintain the 
stored water temperature expressed as a percentage of the heat 
content of the stored water above room temperature

    6.7.2. The standby loss expressed in Btu per hour must be 
calculated as follows:
    SL (Btu per hour) = S (% per hour) x 8.25 (Btu/gal-[deg]F) x 
Measured Volume (gal) x 70 ([deg]F).
    Where, SL refers to the standby loss of the water heater, defined 
as the amount of energy required to maintain the stored water 
temperature expressed in Btu per hour
    14. Add appendix B to subpart G of part 431 to read as follows:

Appendix B to Subpart G of Part 431--Uniform Test Method for the 
Measurement of Standby Loss of Electric Storage Water Heaters and 
Storage-Type Instantaneous Water Heaters

    Note: Prior to November 6, 2017, manufacturers must make any 
representations with respect to the energy use or efficiency of the 
subject commercial water heating equipment in accordance with the 
results of testing pursuant to this appendix or the procedures in 10 
CFR 431.106 that were in place on January 1, 2016. On and after 
November 6, 2017, manufacturers must make any representations with 
respect to energy use or efficiency of electric storage water heaters 
and storage-type instantaneous water heaters in accordance with the 
results of testing pursuant to this appendix to demonstrate compliance 
with the energy conservation standards at 10 CFR 431.110.

[[Page 79329]]

1. General

    Determine the standby loss in accordance with the following 
sections of this appendix. Certain sections reference sections of Annex 
E.1 of ANSI Z21.10.3-2015 (incorporated by reference; see Sec.  
431.105). Where the instructions contained in the sections below 
conflict with instructions in Annex E.1 of ANSI Z21.10.3-2015, the 
instructions contained in this appendix control.

2. Test Set-Up

    2.1. Placement of Water Heater. A water heater for installation on 
combustible floors must be placed on a \3/4\-inch plywood platform 
supported by three 2 x 4-inch runners. If the water heater is for 
installation on noncombustible floors, suitable noncombustible material 
must be placed on the platform. When the use of the platform for a 
large water heater is not practical, the water heater may be placed on 
any suitable flooring. A wall-mounted water heater must be mounted on a 
simulated wall section.
    2.2. Installation of Temperature Sensors. Inlet and outlet piping 
must be turned vertically downward from the connections on a tank-type 
water heater so as to form heat traps. Temperature sensors for 
measuring supply water temperature must be installed upstream of the 
inlet heat trap piping, in accordance with Figure 2.1, 2.2, or 2.3 (as 
applicable) of this appendix.
    The water heater must meet the requirements shown in either Figure 
2.1, 2.2, or 2.3 (as applicable) at all times during the conduct of the 
standby loss test. Any factory-supplied heat traps must be installed 
per the installation instructions while ensuring the requirements in 
Figure 2.1, 2.2, or 2.3 are met. All dimensions specified in Figure 
2.1, 2.2, and 2.3 are measured from the outer surface of the pipes and 
water heater outer casing (as applicable).

[[Page 79330]]

[GRAPHIC] [TIFF OMITTED] TR10NO16.017


[[Page 79331]]


[GRAPHIC] [TIFF OMITTED] TR10NO16.018

    2.3. Installation of Temperature Sensors for Measurement of Mean 
Tank Temperature. Install temperature sensors inside the tank for 
measurement of mean tank temperature according to the instructions in 
paragraph f of Annex E.1 of ANSI Z21.10.3-2015 (incorporated by 
reference; see Sec.  431.105 rt). Calculate the mean tank temperature 
as the average of the six installed temperature sensors.
    2.4. Piping Insulation. Insulate all water piping external to the 
water heater jacket, including heat traps and piping that is installed 
by the manufacturer or shipped with the unit, for at least 4 ft of 
piping length from the connection at the appliance, with material 
having an R-value not less than 4 [deg]F[middot]ft\2\[middot]h/Btu. 
Ensure that the insulation does not contact any appliance surface 
except at the location where the pipe connections penetrate the 
appliance jacket or enclosure.
    2.5. Temperature and Pressure Relief Valve Insulation. If the 
manufacturer or has not provided a temperature and pressure relief 
valve, one shall be installed and insulated as specified in section 2.4 
of this appendix.
    2.6. Energy Consumption. Install equipment that determines, within 
 1 percent, the quantity of electricity consumed by 
factory-supplied water heater components.

3. Test Conditions

3.1. Water Supply
    3.1.1. Water Supply Pressure. The pressure of the water supply must 
be maintained between 40 psi and the maximum pressure specified by the 
manufacturer of the unit being tested. The accuracy of the pressure-
measuring devices must be within  1.0 pounds per square 
inch (psi).
    3.1.2. Water Supply Temperature. When filling the tank with water 
prior to the soak-in period, maintain the supply water temperature at 
70 [deg]F  2[emsp14][deg]F.
    3.1.3. Isolate the water heater using a shutoff valve in the supply 
line with an expansion tank installed in the supply line downstream of 
the shutoff valve. There must be no shutoff means between the expansion 
tank and the appliance inlet.
    3.2. Electrical Supply. Maintain the electrical supply voltage to 
within  5 percent of the voltage specified on the water 
heater nameplate. If a voltage range is specified on the nameplate, 
maintain the voltage to within  5 percent of the center of 
the voltage range specified on the nameplate.
    3.3. Ambient Room Temperature. During the soak-in period and the 
standby loss test, maintain the ambient room temperature at 75 [deg]F 
 10 [deg]F at all times. Measure the ambient room 
temperature at 1-minute intervals during these periods, except for the 
soak-in period. Measure the ambient room temperature once before 
beginning the soak-in period, and ensure no actions are taken during 
the soak-in period that would cause the ambient room temperature to 
deviate from the allowable range. Measure the ambient room temperature 
at the vertical mid-point of the water heater and approximately 2 feet 
from the water heater jacket. Shield the sensor against radiation. 
Calculate the average ambient room temperature for the standby loss 
test. During the standby loss test, the ambient room temperature must 
not vary by more than  5.0 [deg]F at any reading from the 
average ambient room temperature.
    3.4. Maximum Air Draft. During the standby loss test, the water 
heater must be located in an area protected from drafts of more than 50 
ft/min. Prior to beginning the standby loss test, measure the air draft 
within three feet of the jacket of the water heater to ensure this 
condition is met. Ensure that no other changes that would increase the 
air draft are made to the test set-up or conditions during the conduct 
of the test.
    3.5. Setting the Tank Thermostat(s). Before starting the required 
soak-in period, the thermostat setting(s) must first be obtained as 
explained in the following sections. The thermostat setting(s) must be 
obtained by starting with the tank full of water at 70 [deg]F  2 [deg]F. After the tank is completely filled with water at 70 
[deg]F  2 [deg]F, turn off the water flow, and set the 
thermostat(s) as follows.
    3.5.1. For water heaters with a single thermostat, the thermostat 
setting must be set so that the maximum mean tank temperature after 
cut-out is 140 [deg]F  5 [deg]F.
    3.5.2. For water heaters with multiple adjustable thermostats, set 
only the

[[Page 79332]]

topmost and bottommost thermostats, and turn off any other thermostats 
for the duration of the standby loss test. Set the topmost thermostat 
first to yield a maximum mean water temperature after cut-out of 
140[emsp14][deg]F  5[emsp14][deg]F, as calculated using 
only the temperature readings measured at locations in the tank higher 
than the heating element corresponding to the topmost thermostat (the 
lowermost heating element corresponding to the topmost thermostat if 
the thermostat controls more than one element). While setting the 
topmost thermostat, all lower thermostats must be turned off so that no 
elements below that (those) corresponding to the topmost thermostat are 
in operation. After setting the topmost thermostat, set the bottommost 
thermostat to yield a maximum mean water temperature after cut-out of 
140[emsp14][deg]F  5[emsp14][deg]F. When setting the 
bottommost thermostat, calculate the mean tank temperature using all 
the temperature sensors installed in the tank as per section 2.3 of 
this appendix.
    3.6. Data Collection Intervals. Follow the data recording intervals 
specified in the following sections.
    3.6.1. Soak-In Period. Measure the ambient room temperature, in 
[deg]F, every minute during the soak-in period.
    3.6.2. Standby Loss Test. Follow the data recording intervals 
specified in Table 3.1 of this appendix. Additionally, the electricity 
consumption over the course of the entire test must be measured and 
used in calculation of standby loss.

 Table 3.1--Data To Be Recorded Before and During the Standby Loss Test
------------------------------------------------------------------------
                                                        Every 1  minute
         Item recorded               Before test              \a\
------------------------------------------------------------------------
Air draft, ft/min..............  X..................  ..................
Time, minutes/seconds..........  ...................  X
Mean tank temperature, [deg]F..  ...................  X \b\
Ambient room temperature,        ...................  X
 [deg]F.
------------------------------------------------------------------------
Notes:
\a\ These measurements are to be recorded at the start and end of the
  test, as well as every minute during the test.
\b\ Mean tank temperature is calculated as the average of the 6 tank
  temperature sensors, installed per section 2.3 of this appendix.

    4. Determination of Storage Volume. Determine the storage volume by 
subtracting the tare weight, measured while the system is dry and 
empty, from the weight of the system when filled with water and 
dividing the resulting net weight of water by the density of water at 
the measured water temperature. The volume of water contained in the 
water heater must be computed in gallons.

5. Standby Loss Test

    5.1. If no settings on the water heater have changed and the water 
heater has not been turned off since a previously run standby loss 
test, skip to section 5.3 of this appendix. Otherwise, conduct the 
soak-in period according to section 5.2 of this appendix.
    5.2. Soak-In Period. Conduct a soak-in period, in which the water 
heater must sit without any draws taking place for at least 12 hours. 
Begin the soak-in period after setting the tank thermostat(s) as 
specified in section 3.5 of this appendix, and maintain these settings 
throughout the soak-in period.
    5.3. Begin the standby loss test at the first cut-out following the 
end of the soak-in period (if applicable), or at a cut-out following 
the previous standby loss test (if applicable). Allow the water heater 
to remain in standby mode. At this point, do not change any settings on 
the water heater until measurements for the standby loss test are 
finished. Begin recording applicable parameters as specified in section 
3.6.2 of this appendix.
    5.4. At the second cut-out, record the time and ambient room 
temperature, and begin measuring the electric consumption. Record the 
initial mean tank temperature and initial ambient room temperature. For 
the remainder of the test, continue recording the applicable parameters 
specified in section 3.6.2 of this appendix.
    5.5. Stop the test after the first cut-out that occurs after 24 
hours, or at 48 hours, whichever comes first.
    5.6. Immediately after conclusion of the standby loss test, record 
the total electrical energy consumption, the final ambient room 
temperature, the duration of the standby loss test, and if the test 
ends at 48 hours without a cut-out, the final mean tank temperature, or 
if the test ends after a cut-out, the maximum mean tank temperature 
that occurs after the cut-out. Calculate the average of the recorded 
values of the mean tank temperature and of the ambient air temperatures 
taken at each measurement interval, including the initial and final 
values.
    5.7. Standby Loss Calculation. To calculate the standby loss, 
follow the steps below:
    5.7.1 The standby loss expressed as a percentage (per hour) of the 
heat content of the stored water above room temperature must be 
calculated using the following equation:
[GRAPHIC] [TIFF OMITTED] TR10NO16.019

Where,
[Delta]T3 = Average value of the mean tank temperature 
minus the average value of the ambient room temperature, expressed 
in [deg]F
[Delta]T4 = Final mean tank temperature measured at the 
end of the test minus the initial mean tank temperature measured at 
the start of the test, expressed in [deg]F
k = 8.25 Btu/gallon[middot][deg]F, the nominal specific heat of 
water
Va = Volume of water contained in the water heater in 
gallons measured in accordance with section 4 of this appendix
Et = Thermal efficiency = 98 percent for electric water 
heaters with immersed heating elements
Ec = Electrical energy consumed by the water heater 
during the duration of the test in Btu
t = Total duration of the test in hours
S = Standby loss, the average hourly energy required to maintain the 
stored water temperature expressed as a percentage of the heat 
content of the stored water above room temperature


0
15. Add appendix C to subpart G of part 431 to read as follows:

Appendix C to Subpart G of Part 431--Uniform Test Method for the 
Measurement of Thermal Efficiency and Standby Loss of Gas-Fired and 
Oil-Fired Instantaneous Water Heaters and Hot Water Supply Boilers 
(Other Than Storage-Type Instantaneous Water Heaters)

    Note: Prior to November 6, 2017, manufacturers must make any 
representations with respect to the energy use or efficiency of the 
subject commercial water heating equipment in accordance with the 
results of testing pursuant to this appendix or the procedures in 10 
CFR 431.106 that were in place on January 1, 2016. On and after 
November 6, 2017, manufacturers must make any

[[Page 79333]]

representations with respect to energy use or efficiency of gas-
fired and oil-fired instantaneous water heaters and hot water supply 
boilers (other than storage-type instantaneous water heaters) in 
accordance with the results of testing pursuant to this appendix to 
demonstrate compliance with the energy conservation standards at 10 
CFR 431.110.

1. General
    Determine the thermal efficiency and standby loss (as applicable) 
in accordance with the following sections of this appendix. Certain 
sections reference sections of Annex E.1 of ANSI Z21.10.3-2015 
(incorporated by reference; see Sec.  431.105). Where the instructions 
contained in the sections below conflict with instructions in Annex E.1 
of ANSI Z21.10.3-2015, the instructions contained in this appendix 
control.
2. Test Set-Up
    2.1. Placement of Water Heater. A water heater for installation on 
combustible floors must be placed on a \3/4\-inch plywood platform 
supported by three 2 x 4-inch runners. If the water heater is for 
installation on noncombustible floors, suitable noncombustible material 
must be placed on the platform. When the use of the platform for a 
large water heater is not practical, the water heater may be placed on 
any suitable flooring. A wall-mounted water heater must be mounted on a 
simulated wall section.
    2.2. Test Configuration. If the instantaneous water heater or hot 
water supply boiler is not required to be tested using a recirculating 
loop, then set up the unit in accordance with Figures 2.1, 2.2, or 2.3 
of this appendix (as applicable). If the unit is required to be tested 
using a recirculating loop, then set up the unit as per Figure 2.4 of 
this appendix.
BILLING CODE 6450-01-P

[[Page 79334]]

[GRAPHIC] [TIFF OMITTED] TR10NO16.020


[[Page 79335]]


[GRAPHIC] [TIFF OMITTED] TR10NO16.021

    2.2.1. If the instantaneous water heater or hot water supply boiler 
does not have any external piping, install an outlet water valve within 
10 inches of piping length of the water heater jacket or enclosure. If 
the instantaneous water

[[Page 79336]]

heater or hot water supply boiler includes external piping assembled at 
the manufacturer's premises prior to shipment, install water valves in 
the outlet piping within 5 inches of the end of the piping supplied 
with the unit.
    2.2.2. If the water heater is not able to achieve an outlet water 
temperature of 70[emsp14][deg]F  2[emsp14][deg]F 
(TOWT) above the supply water temperature at full firing 
rate, a recirculating loop with pump as shown in Figure 2.4 of this 
appendix must be used.
    2.2.2.1. If a recirculating loop with a pump is used, then ensure 
that the inlet water temperature labeled as TIWT in Figure 
2.4 of this appendix, is greater than or equal to 70[emsp14][deg]F and 
less than or equal to 120[emsp14][deg]F at all times during the thermal 
efficiency test and steady-state verification period (as applicable).
2.3. Installation of Temperature Sensors
    2.3.1. Without Recirculating Loop.
    2.3.1.1. Vertical Connections. Use Figure 2.1 (for top connections) 
and 2.2 (for bottom connections) of this appendix.
    2.3.1.2. Horizontal Connections. Use Figure 2.3 of this appendix.
    2.3.2. With Recirculating Loop. Set up the recirculating loop as 
shown in Figure 2.4 of this appendix.
    2.3.3. For water heaters with multiple outlet water connections 
leaving the water heater jacket that are required to be operated to 
achieve the rated input, temperature sensors must be installed for each 
outlet water connection leaving the water heater jacket or enclosure 
that is used during testing, in accordance with the provisions in 
sections 2.3.1 and 2.3.2 of this appendix (as applicable).
    2.4. Piping Insulation. Insulate all water piping external to the 
water heater jacket or enclosure, including piping that is installed by 
the manufacturer or shipped with the unit, for at least 4 ft of piping 
length from the connection at the appliance with material having an R-
value not less than 4[emsp14][deg]F[middot]ft\2\[middot]h/Btu. Ensure 
that the insulation does not contact any appliance surface except at 
the location where the pipe connections penetrate the appliance jacket 
or enclosure.
    2.5. Temperature and Pressure Relief Valve Insulation. If the 
manufacturer has not provided a temperature and pressure relief valve, 
one shall be installed and insulated as specified in section 2.4 of 
this appendix. The temperature and pressure relief valve must be 
installed in the outlet water piping, between the unit being tested and 
the outlet water valve.
    2.6. Vent Requirements. Follow the requirements for venting 
arrangements specified in paragraph c of Annex E.1 of ANSI Z21.10.3-
2015 (incorporated by reference; see Sec.  431.105).
    2.7. Energy Consumption. Install equipment that determines, within 
 1 percent:
    2.7.1. The quantity and rate of fuel consumed.
    2.7.2. The quantity of electricity consumed by factory-supplied 
water heater components, and of the test loop recirculating pump, if 
used.
3. Test Conditions
3.1. Water Supply
    3.1.1. Water Supply Pressure. The pressure of the water supply must 
be maintained between 40 psi and the maximum pressure specified by the 
manufacturer of the unit being tested. The accuracy of the pressure-
measuring devices must be within  1.0 psi.
    3.1.2. Water Supply Temperature. During the thermal efficiency test 
and steady-state verification period (as applicable), the temperature 
of the supply water (TSWT) must be maintained at 
70[emsp14][deg]F  2[emsp14][deg]F.
    3.2. Gas Pressure for Gas-Fired Equipment. The supply gas pressure 
must be within the range specified by the manufacturer on the nameplate 
of the unit being tested. The difference between the outlet pressure of 
the gas appliance pressure regulator and the value specified by the 
manufacturer on the nameplate of the unit being tested must not exceed 
the greater of:  10 percent of the nameplate value or 
 0.2 inches water column (in. w.c.). Obtain the higher 
heating value of the gas burned.
    3.3. Ambient Room Temperature. Maintain the ambient room 
temperature at 75[emsp14][deg]F  10[emsp14][deg]F at all 
times during the steady-state verification period, the thermal 
efficiency test, and the standby loss test (as applicable). Measure the 
ambient room temperature at 1-minute intervals during these periods. 
Measure the ambient room temperature at the vertical mid-point of the 
water heater and approximately 2 feet from the water heater jacket or 
enclosure. Shield the sensor against radiation. Calculate the average 
ambient room temperature separately for the thermal efficiency test and 
the standby loss test. During the thermal efficiency and standby loss 
tests, the ambient room temperature must not vary by more than  5.0[emsp14][deg]F at any reading from the average ambient room 
temperature.
    3.4. Test Air Temperature. During the steady-state verification 
period, the thermal efficiency test, and the standby loss test (as 
applicable), the test air temperature must not vary by more than  5[emsp14][deg]F from the ambient room temperature at any 
reading. Measure the test air temperature at 1-minute intervals during 
these periods and at a location within two feet of the air inlet of the 
water heater or the combustion air intake vent, as applicable. Shield 
the sensor against radiation. For units with multiple air inlets, 
measure the test air temperature at each air inlet, and maintain the 
specified tolerance on deviation from the ambient room temperature at 
each air inlet. For units without a dedicated air inlet, measure the 
test air temperature within two feet of any location on the water 
heater where combustion air is drawn.
    3.5. Maximum Air Draft. During the steady-state verification 
period, the thermal efficiency test, and the standby loss test (as 
applicable), the water heater must be located in an area protected from 
drafts of more than 50 ft/min. Prior to beginning the steady-state 
verification period and the standby loss test, measure the air draft 
within three feet of the jacket or enclosure of the water heater to 
ensure this condition is met. Ensure that no other changes that would 
increase the air draft are made to the test set-up or conditions during 
the conduct of the tests.
3.6. Primary Control
    3.6.1. Thermostatically-Activated Water Heaters With an Internal 
Thermostat. Before starting the thermal efficiency test and the standby 
loss test (unless the thermostat is already set before the thermal 
efficiency test), the thermostat setting must be obtained. Set the 
thermostat to ensure:
    3.6.1.1. With supply water temperature set as per section 3.1.2 of 
this appendix (i.e., 70[emsp14][deg]F  2[emsp14][deg]F) the 
water flow rate can be varied so that the outlet water temperature is 
constant at 70[emsp14][deg]F  2[emsp14][deg]F above the 
supply water temperature, while the burner is firing at full firing 
rate; and
    3.6.1.2. After the water supply is turned off and the thermostat 
reduces the fuel supply to a minimum, the maximum heat exchanger outlet 
water temperature (TOHX) is 140[emsp14][deg]F  
5[emsp14][deg]F.
    3.6.1.3. If the water heater includes a built-in safety mechanism 
that prevents it from achieving a heat exchanger outlet water 
temperature of 140[emsp14][deg]F  5[emsp14][deg]F, adjust 
the thermostat to its maximum setting.
    3.6.2. Flow-Activated Instantaneous Water Heaters and 
Thermostatically-Activated Instantaneous Water Heaters With an External 
Thermostat. Energize the primary control such that it is always calling 
for heating and the burner is firing at the full firing rate. Maintain 
the supply water temperature as per section 3.1.2 of this appendix

[[Page 79337]]

(i.e., 70[emsp14][deg]F  2[emsp14][deg]F). Set the control 
so that the outlet water temperature (TOWT) is 
140[emsp14][deg]F  5[emsp14][deg]F. If the water heater 
includes a built-in safety mechanism that prevents it from achieving a 
heat exchanger outlet water temperature of 140[emsp14][deg]F  5[emsp14][deg]F, adjust the control to its maximum setting.
3.7. Units With Multiple Outlet Water Connections
    3.7.1. For each connection leaving the water heater that is 
required for the unit to achieve the rated input, the outlet water 
temperature must not differ from that of any other outlet water 
connection by more than 2[emsp14][deg]F during the steady-state 
verification period and thermal efficiency test.
    3.7.2. Determine the outlet water temperature representative for 
the entire unit at every required measurement interval by calculating 
the average of the outlet water temperatures measured at each 
connection leaving the water heater jacket or enclosure that is used 
during testing. Use the outlet water temperature representative for the 
entire unit in all calculations for the thermal efficiency and standby 
loss tests, as applicable.
    3.8. Additional Requirements for Oil-Fired Equipment.
    3.8.1. Venting Requirements. Connect a vertical length of flue pipe 
to the flue gas outlet of sufficient height so as to meet the minimum 
draft specified by the manufacturer.
    3.8.2. Oil Supply. Adjust the burner rate so that the following 
conditions are met:
    3.8.2.1. The CO2 reading is within the range specified 
by the manufacturer;
    3.8.2.2. The fuel pump pressure is within  10 percent 
of manufacturer's specifications;
    3.8.2.3. If either the fuel pump pressure or range for 
CO2 reading are not specified by the manufacturer on the 
nameplate of the unit, in literature shipped with the unit, or in 
supplemental test report instructions included with a certification 
report, then a default value of 100 psig is to be used for fuel pump 
pressure, and a default range of 9-12 percent is to be used for 
CO2 reading; and
    3.8.2.4. Smoke in the flue does not exceed No. 1 smoke as measured 
by the procedure in ASTM D2156-09 (Reapproved 2013) (incorporated by 
reference, see Sec.  431.105). To determine the smoke spot number, the 
smoke measuring device shall be connected to an open-ended tube. This 
tube must project into the flue \1/4\ to \1/2\ of the pipe diameter.
    3.8.2.5. If no settings on the water heater have been changed and 
the water heater has not been turned off since the end of a previously 
run thermal efficiency (or standby loss test for thermostatically-
activated instantaneous water heaters with an internal thermostat), 
measurement of the CO2 reading and conduct of the smoke spot 
test are not required prior to beginning a test. Otherwise, measure the 
CO2 reading and determine the smoke spot number, with the 
burner firing, before beginning measurements for the steady-state 
verification period (prior to beginning the thermal efficiency test or 
standby loss test, as applicable). However, measurement of the 
CO2 reading and conduct of the smoke spot test are not 
required for the standby loss test for thermostatically-activated 
instantaneous water heaters with an external thermostat and flow-
activated instantaneous water heaters.
    3.9. Data Collection Intervals. Follow the data recording intervals 
specified in the following sections.
    3.9.1. Steady-State Verification Period and Thermal Efficiency 
Test. For the steady-state verification period and the thermal 
efficiency test, follow the data recording intervals specified in Table 
3.1 of this appendix. These data recording intervals must also be 
followed if conducting a steady-state verification period prior to 
conducting the standby loss test.

  Table 3.1--Data To Be Recorded Before and During the Steady-State Verification Period and Thermal Efficiency
                                                      Test
----------------------------------------------------------------------------------------------------------------
                                         Before steady-state
            Item recorded                verification period       Every 1 minute \a\        Every 10 minutes
----------------------------------------------------------------------------------------------------------------
Gas supply pressure, in w.c.........  X.......................  .......................  .......................
Gas outlet pressure, in w.c.........  X.......................  .......................  .......................
Barometric pressure, in Hg..........  X.......................  .......................  .......................
Fuel higher heating value, Btu/ft     X.......................  .......................  .......................
 \3\ (gas) or Btu/lb (oil).
Oil pump pressure, psig (oil only)..  X.......................  .......................  .......................
CO2 reading, % (oil only)...........  X \b\...................  .......................  .......................
Oil smoke spot reading (oil only)...  X \b\...................  .......................  .......................
Air draft, ft/min...................  X.......................  .......................  .......................
Time, minutes/seconds...............  ........................  X......................  .......................
Fuel weight or volume, lb (oil) or    ........................  .......................  X\c\
 ft \3\ (gas).
Supply water temperature (TSWT),      ........................  X......................  .......................
 [deg]F.
Inlet water temperature (TIWT),       ........................  X \d\..................  .......................
 [deg]F.
Outlet water temperature (TOWT),      ........................  X......................  .......................
 [deg]F.
Ambient room temperature, [deg]F....  ........................  X......................  .......................
Test air temperature, [deg]F........  ........................  X......................  .......................
Water flow rate, gpm................  ........................  X......................  .......................
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ These measurements are to be recorded at the start and end of both the steady-state verification period and
  the thermal efficiency test, as well as every minute during both periods.
\b\ The smoke spot test and CO2 reading are not required prior to beginning the steady-state verification period
  if no settings on the water heater have been changed and the water heater has not been turned off since the
  end of a previously-run efficiency test (i.e., thermal efficiency or standby loss).
\c\ Fuel and electricity consumption over the course of the entire thermal efficiency test must be measured and
  used in calculation of thermal efficiency.
\d\ Only measured when a recirculating loop is used.


[[Page 79338]]

    3.9.2. Standby Loss Test. For the standby loss test, follow the 
data recording intervals specified in Table 3.2 of this appendix. 
(Follow the data recording intervals specified in Table 3.1 of this 
appendix of the steady-state verification period, if conducted prior to 
the standby loss test.) Additionally, the fuel and electricity 
consumption over the course of the entire test must be measured and 
used in calculation of standby loss.

 Table 3.2--Data To Be Recorded Before and During the Standby Loss Test
------------------------------------------------------------------------
         Item recorded              Before test     Every 1 minute \a\
-----------------------------------------------------------------------
Gas supply pressure, in w.c...  X.................  ..................
Gas outlet pressure, in w.c...  X.................  ..................
Barometric pressure, in Hg....  X.................  ..................
Fuel higher heating value, Btu/ X.................  ..................
 ft \3\ (gas) or Btu/lb (oil).
Oil pump pressure, psig (oil    X.................  ..................
 only).
Air draft, ft/min.............  X.................  ..................
Time, minutes/seconds.........  ..................  X.................
Heat exchanger outlet water     ..................  X.................
 temperature (TOHX), [deg]F.
Ambient room temperature,       ..................  X.................
 [deg]F.
Test air temperature, [deg]F..  ..................  X.................
Water flow rate, gpm..........  X \b\.............  ..................
Inlet water temperature         X \b\.............  ..................
 (TIWT), [deg]F.
------------------------------------------------------------------------
Notes:
\a\ These measurements are to be recorded at the start and end of the
  test, as well as every minute during the test.
\b\ The water flow rate and supply water temperature and inlet water
  temperature (if a recirculating loop is used) must be measured during
  the steady-state verification period at 1-minute intervals. After the
  steady-state verification period ends, flow rate, supply water
  temperature, and inlet water temperature (if measured) are not
  required to be measured during the standby loss test, as there is no
  flow occurring during the standby loss test.

    4. Determination of Storage Volume. Determine the storage volume by 
subtracting the tare weight, measured while the system is dry and 
empty, from the weight of the system when filled with water and 
dividing the resulting net weight of water by the density of water at 
the measured water temperature. The volume of water contained in the 
water heater must be computed in gallons.
5. Fuel Input Rate
    5.1. Determination of Fuel Input Rate. During the steady-state 
verification period and thermal efficiency test, as applicable, record 
the fuel consumption at 10-minute intervals. Calculate the fuel input 
rate for each 10-minute period using the equations in section 5.2 of 
this appendix. The measured fuel input rates for these 10-minute 
periods must not vary by more than  2 percent between any 
two readings. Determine the overall fuel input rate using the fuel 
consumption for the entire duration of the thermal efficiency test.
    5.2. Fuel Input Rate Calculation. To calculate the fuel input rate, 
use the following equation:
[GRAPHIC] [TIFF OMITTED] TR10NO16.022

Where:

Q = Fuel input rate, expressed in Btu/h
Qs = Total fuel flow as metered, expressed in ft\3\ for 
gas-fired equipment and lb for oil-fired equipment
Cs = Correction applied to the heating value of a gas H, 
when it is metered at temperature and/or pressure conditions other 
than the standard conditions for which the value of H is based. 
Cs=1 for oil-fired equipment.
H = Higher heating value of the fuel, expressed as Btu/ft\3\ for 
gas-fired equipment and Btu/lb for oil-fired equipment.
t = Duration of measurement of fuel consumption

    6. Thermal Efficiency Test. Before beginning the steady-state 
verification period, record the applicable parameters as specified in 
section 3.9.1 of this appendix. Begin drawing water from the unit by 
opening the main supply and outlet water valve, and adjust the water 
flow rate to achieve an outlet water temperature of 70 [deg]F  2 [deg]F above supply water temperature. The thermal efficiency 
test shall be deemed complete when there is a continuous, one-hour-long 
period where the steady-state conditions specified in section 6.1 of 
this appendix have been met, as confirmed by consecutive readings of 
the relevant parameters at 1-minute intervals (except for fuel input 
rate, which is determined at 10-minute intervals, as specified in 
section 5.1 of this appendix). During the one-hour-long period, the 
water heater must fire continuously at its full firing rate (i.e., no 
modulation or cut-outs) and no settings can be changed on the unit 
being tested at any time. The first 30 minutes of the one-hour-period 
where the steady-state conditions in section 6.1 of this appendix are 
met is the steady-state verification period. The final 30 minutes of 
the one-hour-period where the steady-state conditions in section 6.1 of 
this appendix are met is the thermal efficiency test. The last reading 
of the steady-state verification period must be the first reading of 
the thermal efficiency test (i.e., the thermal efficiency test starts 
immediately once the steady-state verification period ends).
    6.1. Steady-State Conditions. The following conditions must be met 
at consecutive readings taken at 1-minute intervals (except for fuel 
input rate, for which measurements are taken at 10-minute intervals) to 
verify the water heater has achieved steady-state operation during the 
steady-state verification period and the thermal efficiency test.
    6.1.1. The water flow rate must be maintained within  
0.25 gallons per minute (gpm) of the initial reading at the start of 
the steady-state verification period.
    6.1.2. Outlet water temperature must be maintained at 70 [deg]F 
 2 [deg]F above supply water temperature.
    6.1.3. Fuel input rate must be maintained within  2 
percent of the rated input certified by the manufacturer.
    6.1.4. The supply water temperature (TSWT) (or inlet 
water temperature (TIWT) if a recirculating loop is used) 
must be maintained within  0.50 [deg]F of the initial 
reading at the start of the steady-state verification period.
    6.1.5. The rise between supply (or inlet if a recirculating loop is 
used) and outlet water temperatures must be maintained within  0.50 [deg]F of its initial value taken at the start of the 
steady-

[[Page 79339]]

state verification period for units with rated input less than 500,000 
Btu/h, and maintained within  1.00 [deg]F of its initial 
value for units with rated input greater than or equal to 500,000 Btu/
h.
    6.2. Water Flow Measurement. Measure the total weight of water 
heated during the 30-minute thermal efficiency test with either a scale 
or a water flow meter. With either method, the error of measurement of 
weight of water heated must not exceed 1 percent of the weight of the 
total draw.
    6.3. Thermal Efficiency Calculation. Thermal efficiency must be 
calculated using data from the 30-minute thermal efficiency test. 
Calculate thermal efficiency, Et, using the following 
equation:
[GRAPHIC] [TIFF OMITTED] TR10NO16.023

Where:

K = 1.004 Btu/lb[middot][deg]F, the nominal specific heat of water 
at 105 [deg]F
W = Total weight of water heated, lb
[theta]1 = Average supply water temperature, expressed in 
[deg]F
[theta]2 = Average outlet water temperature, expressed in 
[deg]F
Q = Total fuel flow as metered, expressed in ft\3\ (gas) or lb (oil)
Cs = Correction applied to the heating value of a gas H, 
when it is metered at temperature and/or pressure conditions other 
than the standard conditions for which the value of H is based. 
Cs=1 for oil-fired equipment.
H = Higher heating value of the fuel, expressed in Btu/ft\3\ (gas) 
or Btu/lb (oil)
Ec = Electrical consumption of the water heater and, when 
used, the test set-up recirculating pump, expressed in Btu

    7. Standby Loss Test. If the standby loss test is conducted 
immediately after a thermal efficiency test and no settings or 
conditions have been changed since the completion of the thermal 
efficiency test, then skip to section 7.2 or 7.3 of this appendix (as 
applicable). Otherwise, perform the steady-state verification in 
section 7.1 of this appendix. For thermostatically-activated 
instantaneous water heaters with an internal thermostat, use section 
7.2 of this appendix to conduct the standby loss test, and for flow-
activated and/or thermostatically-activated instantaneous water heaters 
with an external thermostat use section 7.3 of this appendix to conduct 
the standby loss test.
    7.1. Steady-State Verification Period. For water heaters where the 
standby loss test is not conducted immediately following the thermal 
efficiency test, the steady-state verification period must be conducted 
before starting the standby loss test. Set the primary control in 
accordance with section 3.6 of this appendix, such that the primary 
control is always calling for heat and the water heater is firing 
continuously at the full firing rate (i.e., no modulation or cut-outs). 
Begin drawing water from the unit by opening the main supply and the 
outlet water valve, and adjust the water flow rate to achieve an outlet 
water temperature of 70[emsp14][deg]F  2[emsp14][deg]F 
above supply water temperature. The steady-state verification period is 
complete when there is a continuous 30-minute period where the steady-
state conditions specified in section 7.1.1 of this appendix are met, 
as confirmed by consecutive readings of the relevant parameters 
recorded at 1-minute intervals (except for fuel input rate, which is 
determined at 10-minute intervals, as specified in section 5.1 of this 
appendix).
    7.1.1. Steady-State Conditions. The following conditions must be 
met at consecutive readings taken at 1-minute intervals (except for 
fuel input rate, for which measurements are taken at 10-minute 
intervals) to verify the water heater has achieved steady-state 
operation during the steady-state verification period prior to 
conducting the standby loss test.
    7.1.1.1. The water flow rate must be maintained within  
0.25 gallons per minute (gpm) of the initial reading at the start of 
the steady-state verification period;
    7.1.1.2. Fuel input rate must be maintained within  2 
percent of the rated input certified by the manufacturer;
    7.1.1.3. The supply water temperature (TSWT) (or inlet 
water temperature (TIWT) if a recirculating loop is used) 
must be maintained within  0.50[emsp14][deg]F of the 
initial reading at the start of the steady-state verification period; 
and
    7.1.1.4. The rise between the supply (or inlet if a recirculating 
loop is used) and outlet water temperatures must be maintained within 
 0.50[emsp14][deg]F of its initial value taken at the start 
of the steady-state verification period for units with rated input less 
than 500,000 Btu/h, and maintained within  
1.00[emsp14][deg]F of its initial value for units with rated input 
greater than or equal to 500,000 Btu/h.
    7.2. Thermostatically-Activated Instantaneous Water Heaters with an 
Internal Thermostat. For water heaters that will experience cut-in 
based on a temperature-activated control that is internal to the water 
heater, use the following steps to conduct the standby loss test.
    7.2.1. Immediately after the thermal efficiency test or the steady-
state verification period (as applicable), turn off the outlet water 
valve(s) (installed as per the provisions in section 2.2 of this 
appendix), and the water pump (if applicable) simultaneously and ensure 
that there is no flow of water through the water heater.
    7.2.2. After the first cut-out following the end of the thermal 
efficiency test or steady-state verification period (as applicable), 
allow the water heater to remain in standby mode. Do not change any 
settings on the water heater at any point until measurements for the 
standby loss test are finished. Begin recording the applicable 
parameters specified in section 3.9.2 of this appendix.
    7.2.3. At the second cut-out, record the time and ambient room 
temperature, and begin measuring the fuel and electricity consumption. 
Record the initial heat exchanger outlet water temperature 
(TOHX) and initial ambient room temperature. For the 
remainder of the test, continue recording the applicable parameters 
specified in section 3.9.2 of this appendix.
    7.2.4. Stop the test after the first cut-out that occurs after 24 
hours, or at 48 hours, whichever comes first.
    7.2.5. Immediately after conclusion of the standby loss test, 
record the total fuel flow and electrical energy consumption, the final 
ambient room temperature, the duration of the standby loss test, and if 
the test ends at 48 hours without a cut-out, the final heat exchanger 
outlet temperature, or if the test ends after a cut-out, the maximum 
heat exchanger outlet temperature that occurs after the cut-out. 
Calculate the average of the recorded values of the heat exchanger 
outlet water temperature and the ambient room temperature taken at each 
measurement interval, including the initial and final values.
    7.2.6. Standby Loss Calculation. To calculate the standby loss, 
follow the steps below:
    7.2.6.1. The standby loss expressed as a percentage (per hour) of 
the heat content of the stored water above room temperature must be 
calculated using the following equation:

[[Page 79340]]

[GRAPHIC] [TIFF OMITTED] TR10NO16.024

Where:

[Delta]T3 = Average value of the heat exchanger outlet 
water temperature (TOHX) minus the average value of the 
ambient room temperature, expressed in [deg]F
[Delta]T4 = Final heat exchanger outlet water temperature 
(TOHX) measured at the end of the test minus the initial 
heat exchanger outlet water temperature (TOHX) measured 
at the start of the test, expressed in [deg]F
K = 8.25 Btu/gallon[middot][deg]F, the nominal specific heat of 
water
Va = Volume of water contained in the water heater in 
gallons measured in accordance with section 4 of this appendix
Et = Thermal efficiency of the water heater determined in 
accordance with section 6 of this appendix, expressed in %
Ec = Electrical energy consumed by the water heater 
during the duration of the test in Btu
T = Total duration of the test in hours
Cs = Correction applied to the heating value of a gas H, 
when it is metered at temperature and/or pressure conditions other 
than the standard conditions for which the value of H is based. 
Cs=1 for oil-fired equipment.
Qs = Total fuel flow as metered, expressed in ft\3\ (gas) 
or lb (oil)
H = Higher heating value of gas or oil, expressed in Btu/ft\3\ (gas) 
or Btu/lb (oil)
S = Standby loss, the average hourly energy required to maintain the 
stored water temperature expressed as a percentage of the initial 
heat content of the stored water above room temperature

    7.2.6.2. The standby loss expressed in Btu per hour must be 
calculated as follows:
    SL (Btu per hour) = S (% per hour) x 8.25 (Btu/gal-[deg]F) x 
Measured Volume (gal) x 70 ([deg]F).
    Where, SL refers to the standby loss of the water heater, defined 
as the amount of energy required to maintain the stored water 
temperature expressed in Btu per hour.
    7.3. Flow-Activated and Thermostatically-Activated Instantaneous 
Water Heaters with an External Thermostat. For water heaters that are 
either flow-activated or thermostatically-activated with an external 
thermostat, use the following steps to conduct the standby loss test.
    7.3.1. Immediately after the thermal efficiency test or the steady-
state verification period (as applicable), de-energize the primary 
control to end the call for heating. If the main burners do not cut 
out, then turn off the fuel supply.
    7.3.1.1. If the unit does not have an integral pump purge 
functionality, then turn off the outlet water valve and water pump at 
this time.
    7.3.1.2. If the unit has an integral pump purge functionality, 
allow the pump purge operation to continue. After the pump purge 
operation is complete, immediately turn off the outlet water valve and 
water pump and continue recording the required parameters for the 
remainder of the test.
7.3.2. Recording Data
    7.3.2.1. For units with pump purge functionality, record the 
initial heat exchanger outlet water temperature (TOHX), and 
ambient room temperature when the main burner(s) cut-out or the fuel 
supply is turned off. After the pump purge operation is complete, 
record the time as t = 0 and the initial electricity meter reading. 
Continue to monitor and record the heat exchanger outlet water 
temperature (TOHX) and time elapsed from the start of the 
test, and the electricity consumption as per the requirements in 
section 3.9.2 of this appendix.
    7.3.2.2. For units not equipped with pump purge functionality, 
begin recording the measurements as per the requirements of section 
3.9.2 of this appendix when the main burner(s) cut-out or the fuel 
supply is turned off. Specifically, record the time as t = 0, and 
record the initial heat exchanger outlet water temperature 
(TOHX), ambient room temperature, and electricity meter 
readings. Continue to monitor and record the heat exchanger outlet 
water temperature (TOHX) and the time elapsed from the start 
of the test as per the requirements in section 3.9.2 of this appendix.
    7.3.3. Stopping Criteria. Stop the test when one of the following 
occurs:
    7.3.3.1. The heat exchanger outlet water temperature 
(TOHX) decreases by 35[emsp14][deg]F from its value recorded 
immediately after the main burner(s) has cut-out, and the pump purge 
operation (if applicable) is complete; or
    7.3.3.2. 24 hours have elapsed from the start of the test.
    7.3.4. At the end of the test, record the final heat exchanger 
outlet water temperature (TOHX), fuel consumed, electricity 
consumed from time t=0, and the time elapsed from the start of the 
test.
7.3.5. Standby Loss Calculation
    7.3.5.1. Once the test is complete, use the following equation to 
calculate the standby loss as a percentage (per hour) of the heat 
content of the stored water above room temperature:

[GRAPHIC] [TIFF OMITTED] TR10NO16.025

Where,
[Delta]T1 = Heat exchanger outlet water temperature 
(TOHX) measured after the pump purge operation is 
complete (if the unit is integrated with pump purge functionality); 
or after the main burner(s) cut-out (if the unit is not equipped 
with pump purge functionality) minus heat exchanger outlet water 
temperature (TOHX) measured at the end of the test, 
expressed in [deg]F
[Delta]T2 = Heat exchanger outlet water temperature 
(TOHX) minus the ambient temperature, both measured after 
the main burner(s) cut-out, at the start of the test, expressed in 
[deg]F
K = 8.25 Btu/gallon[middot][deg]F, the nominal specific heat of 
water
Va = Volume of water contained in the water heater in 
gallons measured in accordance with section 4 of this appendix
Et = Thermal efficiency of the water heater determined in 
accordance with section 6 of this appendix, expressed in %
Ec = Electrical energy consumed by the water heater 
during the duration of the test in Btu
t = Total duration of the test in hours
S = Standby loss, the average hourly energy required to maintain the 
stored water temperature expressed as a percentage of the initial 
heat content of the stored water above room temperature

    7.3.5.2. The standby loss expressed in terms of Btu per hour must 
be calculated as follows:
    SL (Btu per hour) = S (% per hour) x 8.25 (Btu/gal-[deg]F) x 
Measured Volume (gal) x 70 ([deg]F)
    Where, SL refers to the standby loss of the water heater, defined 
as the amount of energy required to maintain the stored water 
temperature expressed in Btu per hour.
    16. Add appendix D to subpart G of part 431 to read as follows:

Appendix D to Subpart G of Part 431--Uniform Test Method for the 
Measurement of Standby Loss of Electric Instantaneous Water Heaters 
(Other Than Storage-Type Instantaneous Water Heaters)

    Note: Prior to November 6, 2017, manufacturers must make any 
representations with respect to the energy use or efficiency of the 
subject

[[Page 79341]]

commercial water heating equipment in accordance with the results of 
testing pursuant to this appendix or the procedures in 10 CFR 431.106 
that were in place on January 1, 2016. On and after November 6, 2017, 
manufacturers must make any representations with respect to energy use 
or efficiency of electric instantaneous water heaters (other than 
storage-type instantaneous water heaters) in accordance with the 
results of testing pursuant to this appendix to demonstrate compliance 
with the energy conservation standards at 10 CFR 431.110.
1. General
    Determine the standby loss (as applicable) in accordance with the 
following sections of this appendix.
2. Test Set-Up
    2.1. Placement of Water Heater. A water heater for installation on 
combustible floors must be placed on a \3/4\-inch plywood platform 
supported by three 2 x 4-inch runners. If the water heater is for 
installation on noncombustible floors, suitable noncombustible material 
must be placed on the platform. When the use of the platform for a 
large water heater is not practical, the water heater may be placed on 
any suitable flooring. A wall-mounted water heater must be mounted on a 
simulated wall section.
    2.2. Test Configuration. If the instantaneous water heater is not 
required to be tested using a recirculating loop, then set up the unit 
in accordance with Figure 2.1, 2.2, or 2.3 of this appendix (as 
applicable). If the unit is required to be tested using a recirculating 
loop, then set up the unit as per Figure 2.4 of this appendix.
BILLING CODE 6450-01-P

[[Page 79342]]

[GRAPHIC] [TIFF OMITTED] TR10NO16.026


[[Page 79343]]


[GRAPHIC] [TIFF OMITTED] TR10NO16.027

BILLING CODE 6450-01-C
    2.2.1. If the instantaneous water heater does not have any external 
piping, install an outlet water valve within 10 inches of the piping 
length of the water heater jacket or enclosure. If the instantaneous 
water heater includes external piping assembled at the manufacturer's 
premises prior to

[[Page 79344]]

shipment, install water valves in the outlet piping within 5 inches of 
the end of the piping supplied with the unit.
    2.2.2. If the water heater is not able to achieve an outlet water 
temperature of 70[emsp14][deg]F  2[emsp14][deg]F above the 
supply water temperature at a constant maximum electricity input rate, 
a recirculating loop with pump as shown in Figure 2.4 of this appendix 
must be used.
    2.2.2.1. If a recirculating loop with a pump is used, then ensure 
that the inlet water temperature (labeled as TIWT in Figure 
2.4 of this appendix) is greater than or equal to 70 [deg]F and less 
than or equal to 120 [deg]F at all times during the steady-state 
verification period.
2.3. Installation of Temperature Sensors
2.3.1. Without Recirculating Loop
    2.3.1.1. Vertical Connections. Use Figure 2.1 (for top connections) 
and 2.2 (for bottom connections) of this appendix.
    2.3.1.2. Horizontal Connections. Use Figure 2.3 of this appendix.
    2.3.2. With Recirculating Loop. Set up the recirculating loop as 
shown in Figure 2.4 of this appendix.
    2.3.3. For water heaters with multiple outlet water connections 
leaving the water heater jacket that are required to be operated to 
achieve the rated input, temperature sensors must be installed for each 
outlet water connection leaving the water heater jacket or enclosure 
that is used during testing, in accordance with sections 2.3.1 and 
2.3.2 of this appendix.
    2.4. Piping Insulation. Insulate all the water piping external to 
the water heater jacket or enclosure, including piping that is 
installed by the manufacturer or shipped with the unit, for at least 4 
ft of piping length from the connection at the appliance with material 
having an R-value not less than 4 [deg]F[middot]f \t2\[middot]h/Btu. 
Ensure that the insulation does not contact any appliance surface 
except at the location where the pipe connections penetrate the 
appliance jacket or enclosure.
    2.5. Temperature and Pressure Relief Valve Insulation. If the 
manufacturer has not provided a temperature and pressure relief valve, 
one shall be installed and insulated as specified in section 2.4 of 
this appendix. The temperature and pressure relief valve must be 
installed in the outlet water piping between the unit being tested and 
the outlet water valve.
    2.6. Energy Consumption. Install equipment that determines, within 
 1 percent, the quantity of electricity consumed by 
factory-supplied water heater components, and of the test loop 
recirculating pump, if used.
3. Test Conditions
3.1. Water Supply
    3.1.1. Water Supply Pressure. The pressure of the water supply must 
be maintained between 40 psi and the maximum pressure specified by the 
manufacturer of the unit being tested. The accuracy of the pressure-
measuring devices must be  1.0 psi.
    3.1.2. Water Supply Temperature. During the steady-state 
verification period, the temperature of the supply water 
(TSWT) must be maintained at 70 [deg]F  2 
[deg]F.
    .2. Electrical Supply. Maintain the electrical supply voltage to 
within  5 percent of the voltage specified on the water 
heater nameplate. If a voltage range is specified on the nameplate, 
maintain the voltage to within  5 percent of the center of 
the voltage range specified on the nameplate.
    3.3. Ambient Room Temperature. Maintain the ambient room 
temperature at 75[deg]F  10 [deg]F at all times during the 
steady-state verification period and the standby loss test. Measure the 
ambient room temperature at 1-minute intervals during these periods. 
Measure the ambient room temperature at the vertical mid-point of the 
water heater and approximately 2 feet from the water heater jacket or 
enclosure. Shield the sensor against radiation. Calculate the average 
ambient room temperature for the standby loss test. During the standby 
loss test, the ambient room temperature must not vary more than  5.0 [deg]F at any reading from the average ambient room 
temperature.
    3.4. Maximum Air Draft. During the steady-state verification period 
and the standby loss test, the water heater must be located in an area 
protected from drafts of more than 50 ft/min. Prior to beginning 
steady-state verification before the standby loss test, measure the air 
draft within three feet of the jacket or enclosure of the water heater 
to ensure this condition is met. Ensure that no other changes that 
would increase the air draft are made to the test set-up or conditions 
during the conduct of the test.
3.5. Primary Control
    3.5.1. Thermostatically-Activated Water Heaters with an Internal 
Thermostat. Before starting the steady-state verification prior to the 
standby loss test, the thermostat setting must be obtained. Set the 
thermostat to ensure:
    3.5.1.1. With supply water temperature as per section 3.1.2 of this 
appendix (i.e., 70 [deg]F  2 [deg]F) the water flow rate 
can be varied so that the outlet water temperature is constant at 70 
[deg]F  2 [deg]F above the supply water temperature, while 
the heating element is operating at the rated input.
    3.5.1.2. After the water supply is turned off and the thermostat 
reduces the electricity supply to the heating element to a minimum, the 
maximum heat exchanger outlet water temperature (TOHX) is 
140 [deg]F  5 [deg]F.
    3.5.1.3. If the water heater includes a built-in safety mechanism 
that prevents it from achieving a heat exchanger outlet water 
temperature of 140 [deg]F  5 [deg]F, adjust the thermostat 
to its maximum setting.
    3.5.2. Flow-Activated Instantaneous Water Heaters and 
Thermostatically-Activated Instantaneous Water Heaters with an External 
Thermostat. Before starting the steady-state verification prior to the 
standby loss test energize the primary control such that it is always 
calling for heating and the heating element is operating at the rated 
input. Maintain the supply water temperature as per section 3.1.2 of 
this appendix (i.e., 70 [deg]F  2 [deg]F). Set the control 
so that the outlet water temperature (TOWT) is 140 [deg]F 
 5 [deg]F. If the water heater includes a built-in safety 
mechanism that prevents it from achieving a heat exchanger outlet water 
temperature of 140 [deg]F  5 [deg]F, adjust the control to 
its maximum setting.
3.6. For Units With Multiple Outlet Water Connections
    3.6.1. For each connection leaving the water heater that is 
required for the unit to achieve the rated input, the outlet water 
temperature must not differ from that of any other outlet water 
connection by more than 2 [deg]F during the steady-state verification 
period prior to the standby loss test.
    3.6.2. Determine the outlet water temperature representative for 
the entire unit at every required measurement interval by calculating 
the average of the outlet water temperatures measured at each 
connection leaving the water heater jacket or enclosure that is used 
during testing. Use the outlet water temperature representative for the 
entire unit in all calculations for the standby loss test.
    3.7. Data Collection Intervals. During the standby loss test, 
follow the data recording intervals specified in Table 3.1 of this 
appendix. Also, the electricity consumption over the course of the 
entire test must be measured and used in calculation of standby loss.
    3.7.1. Steady-State Verification Period. Follow the data recording 
intervals specified in Table 3.1 of this appendix.

[[Page 79345]]



              Table 3.1--Data to be Recorded Before and During the Steady-State Verification Period
----------------------------------------------------------------------------------------------------------------
                                         Before steady-state
            Item recorded                verification period       Every 1 minute \a\        Every 10 minutes
----------------------------------------------------------------------------------------------------------------
Air draft, ft/min...................  X.......................
Time, minutes/seconds...............  ........................  X......................
Electricity Consumed, Btu...........  ........................  .......................  X
Supply water temperature (TSWT),      ........................  X......................
 [deg]F.
Inlet water temperature (TIWT),       ........................  X \b\..................
 [deg]F.
Outlet water temperature (TOWT),      ........................  X......................
 [deg]F.
Ambient room temperature, [deg]F....  ........................  X......................
Water flow rate, (gpm)..............  ........................  X......................
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ These measurements are to be recorded at the start and end, as well as every minute of the steady-state
  verification period.
\b\ Only measured when a recirculating loop is used.

    3.7.2. Standby Loss Test. Follow the data recording intervals 
specified in Table 3.2 of this appendix. Additionally, the electricity 
consumption over the course of the entire test must be measured and 
used in calculation of standby loss.

 Table 3.2--Data to be Recorded Before and During the Standby Loss Test
------------------------------------------------------------------------
         Item recorded               Before test      Every 1 minute \a\
------------------------------------------------------------------------
Air draft, ft/min..............  X..................
Time, minutes/seconds..........  ...................  X
Heat exchanger outlet water      ...................  X
 temperature, [deg]F (TOHX).
Ambient room temperature,        ...................  X
 [deg]F.
------------------------------------------------------------------------
Note:
\a\ These measurements are to be recorded at the start and end of the
  test, as well as every minute during the test.

    4. Determination of Storage Volume. Determine the storage volume by 
subtracting the tare weight--measured while the system is dry and 
empty--from the weight of the system when filled with water and 
dividing the resulting net weight of water by the density of water at 
the measured water temperature. The volume of water contained in the 
water heater must be computed in gallons.
    5. Standby Loss Test. Perform the steady-state verification period 
in accordance with section 5.1 of this appendix. For thermostatically-
activated instantaneous water heaters with an internal thermostat, use 
section 5.2 of this appendix to conduct the standby loss test, and for 
flow-activated and/or thermostatically-activated instantaneous water 
heaters with an external thermostat (including remote thermostatically 
activated and/or flow-activated instantaneous water heaters), use 
section 5.3 of this appendix to conduct the standby loss test.
    Set the primary control in accordance with section 3.5 of this 
appendix, such that the primary control is always calling for heat and 
the water heater is operating at its full rated input. Begin drawing 
water from the unit by opening the main supply and the outlet water 
valve, and adjust the water flow rate to achieve an outlet water 
temperature of 70 [deg]F  2 [deg]F above supply water 
temperature. At this time, begin recording the parameters specified in 
section 3.7.1 of this appendix. The steady-state verification period is 
complete when there is a continuous 30-minute period where the steady-
state conditions specified in section 5.1 of this appendix are met, as 
confirmed by consecutive readings of the relevant parameters recorded 
at 1-minute intervals (except for electric power input rate, which is 
determined at 10-minute intervals, as specified in section 3.7.1 of 
this appendix).
    5.1. Steady-State Conditions. The following conditions must be met 
at consecutive readings taken at 1-minute intervals (except for 
electricity input rate, for which measurements are taken at 10-minute 
intervals) to verify the water heater has achieved steady-state 
operation prior to conducting the standby loss test.
    5.1.1. The water flow rate must be maintained within  
0.25 gallons per minute (gpm) of the initial reading at the start of 
the steady-state verification period;
    5.1.2. Electric power input rate must be maintained within 2 
percent of the rated input certified by the manufacturer.
    5.1.3. The supply water temperature (or inlet water temperature if 
a recirculating loop is used) must be maintained within  
0.50 [deg]F of the initial reading at the start of the steady-state 
verification period; and
    5.1.4. The rise between the supply (or inlet if a recirculating 
loop is used) and outlet water temperatures is maintained within  0.50[emsp14][deg]F of its initial value taken at the start of 
the steady-state verification period for units with rated input less 
than 500,000 Btu/h, and maintained within  
1.00[emsp14][deg]F of its initial value for units with rated input 
greater than or equal to 500,000 Btu/h.
    5.2. Thermostatically-Activated Instantaneous Water Heaters with an 
Internal Thermostat. For water heaters that will experience cut-in 
based on a temperature-activated control that is internal to the water 
heater, use the following steps to conduct the standby loss test.
    5.2.1. Immediately after the steady-state verification period, turn 
off the outlet water valve(s) (installed as per the provisions in 
section 2.2 of this appendix), and the water pump (if applicable) 
simultaneously and ensure that there is no flow of water through the 
water heater.
    5.2.2. After the first cut-out following the steady-state 
verification period,

[[Page 79346]]

allow the water heater to remain in standby mode. Do not change any 
settings on the water heater at any point until measurements for the 
standby loss test are finished. Begin recording the applicable 
parameters specified in section 3.7.2 of this appendix.
    5.2.3. At the second cut-out, record the time and ambient room 
temperature, and begin measuring the electricity consumption. Record 
the initial heat exchanger outlet water temperature (TOHX) 
and initial ambient room temperature. For the remainder of the test, 
continue recording the applicable parameters specified in section 3.7.2 
of this appendix.
    5.2.4. Stop the test after the first cut-out that occurs after 24 
hours, or at 48 hours, whichever comes first.
    5.2.5. Immediately after conclusion of the standby loss test, 
record the total electrical energy consumption, the final ambient room 
temperature, the duration of the standby loss test, and if the test 
ends at 48 hours without a cut-out, the final heat exchanger outlet 
temperature, or if the test ends after a cut-out, the maximum heat 
exchanger outlet temperature that occurs after the cut-out. Calculate 
the average of the recorded values of the heat exchanger outlet water 
temperature and of the ambient air temperatures taken at each 
measurement interval, including the initial and final values.
    5.2.6. Standby Loss Calculation. Calculate the standby loss, 
expressed as a percentage (per hour) of the heat content of the stored 
water above room temperature, using the following equation:
[GRAPHIC] [TIFF OMITTED] TR10NO16.028

Where,

[Delta]T3 = Average value of the heat exchanger outlet 
water temperature (TOHX) minus the average value of the 
ambient room temperature, expressed in [deg]F
[Delta]T4 = Final heat exchanger outlet water temperature 
(TOHX) measured at the end of the test minus the initial 
heat exchanger outlet water temperature (TOHX) measured 
at the start of the test, expressed in [deg]F
k = 8.25 Btu/gallon[middot][deg]F, the nominal specific heat of 
water
Va = Volume of water contained in the water heater in 
gallons measured in accordance with section 4 of this appendix
Et = Thermal efficiency = 98 percent for electric water 
heaters with immersed heating elements
Ec = Electrical energy consumed by the water heater 
during the duration of the test in Btu
t = Total duration of the test in hours
S = Standby loss, the average hourly energy required to maintain the 
stored water temperature expressed as a percentage of the initial 
heat content of the stored water above room temperature

    5.3. Flow-Activated and Thermostatically-Activated Instantaneous 
Water Heaters with an External Thermostat. For water heaters that are 
either flow-activated or thermostatically-activated with an external 
thermostat, use the following steps to conduct the standby loss test:
    5.3.1. Immediately after the steady-state verification period, de-
energize the primary control to end the call for heating. If the 
heating elements do not cut out, then turn off the electricity supply 
to the heating elements. After the heating elements have cut-out, or 
the electricity supply to the heating elements is turned off, begin 
recording the measurements as per the requirements in section 3.7.2 of 
this appendix.
    5.3.1.1. If the unit does not have an integral pump purge 
functionality, then turn off the outlet water valve and water pump 
immediately after the main burners cut-out.
    5.3.1.2. If the unit has an integral pump purge functionality, 
allow the pump purge operation to continue. After the pump purge 
operation is complete, immediately turn off the outlet water valve and 
water pump and continue recording the required parameters for the 
remainder of the test.
5.3.2. Recording Data
    5.3.2.1. For units with pump purge functionality, record the 
initial heat exchanger outlet water temperature (TOHX), and 
ambient room temperature when the main heating element(s) cut-out or 
the electricity supply to the heating element(s) is turned off. After 
the pump purge operation is complete, record the time as t = 0 and the 
initial electricity meter reading. Continue to monitor and record the 
heat exchanger outlet water temperature (TOHX) and time 
elapsed from the start of the test as per the requirements in section 
3.7.2 of this appendix.
    5.3.2.2. For units not equipped with pump purge functionality, 
begin recording the measurements as per the requirements of section 
3.7.2 of this appendix when the main heating element(s) cut-out or the 
electricity supply to the heating element(s) is turned off. 
Specifically, record the time as t = 0, and record the initial heat 
exchanger outlet water temperature (TOHX), ambient room 
temperature, and electricity meter readings. Continue to monitor and 
record the heat exchanger outlet water temperature (TOHX) 
and the time elapsed from the start of the test as per the requirements 
in section 3.7.2 of this appendix.
    5.3.3. Stopping Criteria. Stop the test when one of the following 
occurs:
    5.3.3.1. The heat exchanger outlet water temperature 
(TOHX) decreases by 35[emsp14][deg]F from its value recorded 
after the main heating element(s) have cut-out, and the pump purge 
operation (if applicable) is complete; or
    5.3.3.2. 24 hours have elapsed from the start of the test.
    5.3.4. At the end of the test, record the final heat exchanger 
outlet water temperature (TOHX), electricity consumed from 
time t = 0, and the time elapsed from the start of the test.
    5.3.5. Standby Loss Calculation. Calculate the standby loss, 
expressed as a percentage (per hour) of the heat content of the stored 
water above room temperature, using the following equation:
[GRAPHIC] [TIFF OMITTED] TR10NO16.029

Where,

[Delta]T1 = Heat exchanger outlet water temperature 
(TOHX) measured after the pump purge operation is 
complete (if the unit is integrated with pump purge functionality); 
or after the main heating element(s) cut-out (if the unit is not 
equipped with pump purge functionality) minus heat exchanger outlet 
water temperature (TOHX) measured at the end of the test, 
expressed in [deg]F
[Delta]T2 = Heat exchanger outlet water temperature 
(TOHX) minus the ambient room temperature, both measured 
after the main heating element(s) cut-out at the start of the test, 
expressed in [deg]F
k = 8.25 Btu/gallon[middot][deg]F, the nominal specific heat of 
water
Va = Volume of water contained in the water heater in 
gallons measured in accordance with section 4 of this appendix
Et = Thermal efficiency = 98 percent for electric water 
heaters with immersed heating elements
Ec = Electrical energy consumed by the water heater 
during the duration of the test in Btu
t = Total duration of the test in hours
S = Standby loss, the average hourly energy required to maintain the 
stored water temperature expressed as a percentage of the initial 
heat content of the stored water above room temperature

    17. Add appendix E to subpart G of part 431 to read as follows:

Appendix E to Subpart G of Part 431--Uniform Test Method for the 
Measurement of Energy Efficiency of Commercial Heat Pump Water Heaters

    Note: On and after November 6, 2017, manufacturers must make any

[[Page 79347]]

representations with respect to energy use or efficiency of commercial 
heat pump water heaters in accordance with the results of testing 
pursuant to this appendix.
    1. General. Determine the COPh for commercial heat pump 
water heaters (CHPWHs) using the test procedure set forth below. 
Certain sections below reference ANSI/ASHRAE 118.1-2012 (incorporated 
by reference; see Sec.  431.105). Where the instructions contained 
below differ from those contained in ANSI/ASHRAE 118.1-2012, the 
sections in this appendix control.
    2. Definitions and Symbols. The definitions and symbols are as 
listed in section 3 of ANSI/ASHRAE 118.1-2012.
    3. Instrumentation. The instruments required for the test are as 
described in section 6 of ANSI/ASHRAE 118.1-2012 (except sections 6.3, 
6.4, and 6.6).
    4. Test Set-Up. Follow the provisions described in this section to 
install the CHPWH for testing. Use the test set-up and installation 
instructions set forth for Type IV and Type V equipment (as 
applicable), defined in sections 4.4 and 4.5 of ANSI/ASHRAE 118.1-2012 
and in accordance with the sections below:
    4.1. Test set-up and installation instructions.
    4.1.1. For air-source CHPWHs, set up the unit for testing as per 
section 7.1 and Figure 5a of ANSI/ASHRAE 118.1-2012 for CHPWHs without 
an integral storage tank, and as per Figure 6 in section 7.7.1 of ANSI/
ASHRAE 118.1-2012 for CHPWHs with an integral storage tank.
    4.1.2. For direct geo-exchange CHPWHs, set up the unit for testing 
as per section 7.1 and Figure 5b of ASNI/ASHRAE 118.1-2012 for CHPWHs 
without an integral storage tank, and as per Figure 7 in section 7.7.2 
of ANSI/ASHRAE 118.1-2012 for CHPWHs with an integral storage tank.
    4.1.3. For indoor water-source, ground-source closed-loop, and 
ground water-source CHPWHs, set up the unit for testing as per section 
7.1 and Figure 5c of ANSI/ASHRAE 118.1-2012 for CHPWHs without an 
integral storage tank, and as per Figure 8 in section 7.7.3 of ANSI/
ASHRAE 118.1-2012 for CHPWHs with an integral storage tank.
    4.2. Use the water piping instructions described in section 7.2 of 
ANSI/ASHRAE 118.1-2012 and the special instructions described in 
section 7.7.6 of ANSI/ASHRAE 118.1-2012. Insulate all the pipes used 
for connections with material having a thermal resistance of not less 
than 4 h[middot][deg]F[middot]ft2/Btu for a total piping 
length of not less than 4 feet from the water heater connection ports.
    4.3. Install the thermocouples, including the room thermocouples, 
as per the instructions in sections 7.3.1, 7.3.2, and 7.3.3 (as 
applicable) of ANSI/ASHRAE 118.1-2012.
    4.4. Section 7.6 of ANSI/ASHRAE 118.1-2012 must be used if the 
manufacturer neither submits nor specifies a water pump applicable for 
the unit for laboratory testing.
    4.5. Install the temperature sensors at the locations specified in 
Figure 5a, 5b, 5c, 6, 7, or 8 of ANSI/ASHRAE 118.1-2012, as applicable 
as per section 4.1 of this appendix. The sensor shall be installed in 
such a manner that the sensing portion of the device is positioned 
within the water flow and as close as possible to the center line of 
the pipe. Follow the instructions provided in sections 7.7.7.1 and 
7.7.7.2 of ANSI/ASHRAE 118.1-2012 to install the temperature and flow-
sensing instruments.
    4.6. Use the following evaporator side rating conditions as 
applicable for each category of CHPWHs. These conditions are also 
mentioned in Table 5.1 of this appendix:
    4.6.1. For air-source CHPWHs, maintain the evaporator air entering 
dry-bulb temperature at 80.6 [deg]F  1 [deg]F and wet-bulb 
temperature at 71.2 [deg]F  1 [deg]F throughout the conduct 
of the test.
    4.6.2. For direct geo-exchange CHPWHs, maintain the evaporator 
refrigerant temperature at 32 [deg]F  1 [deg]F.
    4.6.3. For indoor water-source CHPWHs, maintain the evaporator 
entering water temperature at 68 [deg]F  1 [deg]F.
    4.6.4. For ground water-source CHPWHs, maintain the evaporator 
entering water temperature at 50 [deg]F  1 [deg]F.
    4.6.5. For ground-source closed-loop CHPWHs, maintain the 
evaporator entering water temperature at 32 [deg]F  1 
[deg]F.
    4.6.5.1. For ground-source closed-loop CHPWHs, the evaporator water 
must be mixed with 15-percent methanol by-weight to allow the solution 
to achieve the rating conditions required in section 4.6.5.
    4.7. The CHPWH being tested must be installed as per the 
instructions specified in sections 4.1 to 4.6 (as applicable) of this 
appendix. For all other installation requirements, use section 7.7.4 of 
ANSI/ASHRAE 118.1-2012 to resolve any issues related to installation 
(other than what is specified in this test procedure) of the equipment 
for testing. Do not make any alterations to the equipment except as 
specified in this appendix for installation, testing, and the 
attachment of required test apparatus and instruments.
    4.8. Use Table 3 of ANSI/ASHRAE 118.1-2012 for measurement 
tolerances of various parameters.
    4.9. If the CHPWH is equipped with a thermostat that is used to 
control the throttling valve of the equipment, then use the provisions 
in section 7.7.7.3 of ANSI/ASHRAE 118.1-2012 to set up the thermostat.
    4.10. For CHPWHs equipped with an integral storage tank, 
supplemental heat inputs such as electric resistance elements must be 
disabled as per section 7.7.8 of ANSI/ASHRAE 118.1-2012.
    4.11. Install instruments to measure the electricity supply to the 
equipment as specified in section 7.5 of ANSI/ASHRAE 118.1-2012.
5. Test Procedure
    Test all CHPWHs that are not equipped with an integral storage tank 
as per the provisions described in ANSI/ASHRAE 118.1-2012 for ``Type 
IV'' equipment as defined in section 4.4 of ANSI/ASHRAE 118.1-2012. 
Test all CHPWHs that are equipped with an integral storage tank as per 
the provisions described in ANSI/ASHRAE 118.1-2012 for ``Type V'' 
equipment as defined in section 4.5 of ANSI/ASHRAE 118.1-2012. Tests 
for all CHPWHs must follow the steps described below.
    5.1. Supply the CHPWH unit with electricity at the voltage 
specified by the manufacturer. Follow the provisions in section 8.2.1 
of ANSI/ASHRAE 118.1-2012 to maintain the electricity supply at the 
required level.
    5.1.1. For models with multiple voltages specified by the 
manufacturer, use the minimum voltage specified by the manufacturer to 
conduct the test. Maintain the voltage as per the limits specified in 
section 8.2.1 of ANSI/ASHRAE 118.1-2012. The test may be repeated at 
other voltages at the manufacturer's discretion.
    5.2. Set the condenser supply water temperature and outlet water 
temperature per the following provisions and as set forth in Table 5.1 
of this section:

[[Page 79348]]



       Table 5.1--Evaporator and Condenser Side Rating Conditions
------------------------------------------------------------------------
                                 Evaporator side   Condenser side rating
       Category of CHPWH        rating conditions        conditions
------------------------------------------------------------------------
Air-source commercial heat      Evaporator         Entering water
 pump water heater.              entering air       temperature: 70
                                 conditions:.       [deg]F 
                                Dry bulb: 80.6      1 [deg]F. Vary water
                                 [deg]F  1 [deg]F.   needed) to achieve
                                Wet bulb: 71.2      the outlet water
                                 [deg]F  1 [deg]F.   specified in section
                                                    8.7.2 of ANSI/ASHRAE
                                                    118.1-2012.
                                                   If the required
                                                    outlet water
                                                    temperature as
                                                    specified in section
                                                    8.7.2 of ANSI/ASHRAE
                                                    118.1-2012 is not
                                                    met even after
                                                    varying the flow
                                                    rate, then change
                                                    the condenser
                                                    entering water
                                                    temperature to 110
                                                    [deg]F 
                                                    1 [deg]F. Vary flow
                                                    rate to achieve the
                                                    conditions in
                                                    section 8.7.2 of
                                                    ANSI/ASHRAE 118.1-
                                                    2012.
Direct geo-exchange commercial  Evaporator         Entering water
 heat pump water heater.         refrigerant        temperature: 110
                                 temperature: 32    [deg]F 
                                 [deg]F  1 [deg]F.
Indoor water-source commercial  Evaporator         Entering water
 heat pump water heater.         entering water     temperature: 110
                                 temperature: 68    [deg]F 
                                 [deg]F  1 [deg]F.
Ground water-source commercial  Evaporator         Entering water
 heat pump water heater.         entering water     temperature: 110
                                 temperature: 50    [deg]F 
                                 [deg]F  1 [deg]F.
Ground-source closed-loop       Evaporator         Entering water
 commercial heat pump water      entering water     temperature: 110
 heater.                         temperature: 32    [deg]F 
                                 [deg]F  1 [deg]F.
------------------------------------------------------------------------

    5.2.1. For air-source CHPWHs:
    5.2.1.1. Set the supply water temperature to 70 [deg]F  
1 [deg]F. The water pressure must not exceed the maximum working 
pressure rating for the equipment under test.
    5.2.1.2. Use the provisions in section 8.7.1 of ANSI/ASHRAE 118.1-
2012 to set the tank thermostat for CHPWHs equipped with an integral 
storage tank.
    5.2.1.3. Initiate operation at the rated pump flow rate and measure 
the outlet water temperature. If the outlet water temperature is 
maintained at 120 [deg]F  5 [deg]F with no variation in 
excess of 2 [deg]F over a three-minute period, as required by section 
8.7.2 of ANSI/ASHRAE 118.1-2012, skip to section 5.3 of this appendix.
    5.2.1.4. If the outlet water temperature condition as specified in 
section 8.7.2 of ANSI/ASHRAE 118.1-2012 is not achieved, adjust the 
water flow rate over the range of the pump's capacity. If, after 
varying the water flow rate, the outlet water temperature is maintained 
at 120 [deg]F  5 [deg]F with no variation in excess of 2 
[deg]F over a three-minute period, as required by section 8.7.2 of 
ANSI/ASHRAE 118.1-2012, skip to section 5.3 of this appendix.
    5.2.1.5. If, after adjusting the water flow rate within the range 
that is achievable by the pump, the outlet water temperature condition 
as specified in section 8.7.2 of ANSI/ASHRAE 118.1-2012 is still not 
achieved, then change the supply water temperature to 110 [deg]F  1 [deg]F and repeat the instructions from sections 5.2.1.2 and 
5.2.1.4 of this appendix.
    5.2.1. 6. If the outlet water temperature condition cannot be met, 
then a test procedure waiver is necessary to specify an alternative set 
of test conditions.
    5.2.2. For direct geo-exchange, indoor water-source, ground-source 
closed-loop, and ground water-source CHPWHs use the following steps:
    5.2.2.1. Set the condenser supply water temperature to 110 [deg]F 
 1 [deg]F. The water pressure must not exceed the maximum 
working pressure rating for the equipment under test.
    5.2.2.2. Use the provisions in section 8.7.1 of ANSI/ASHRAE 118.1-
2012 to set the tank thermostat for CHPWHs equipped with an integral 
storage tank.
    5.2.2.3. Follow the steps specified in section 8.7.2 of ANSI/ASHRAE 
118.1-2012 to obtain an outlet water temperature of 120 [deg]F  5 [deg]F with no variation in excess of 2 [deg]F over a three-
minute period.
    5.3. Conduct the test as per section 9.1.1, ``Full Input Rating,'' 
of ANSI/ASHRAE 118.1-2012. The flow rate, ``FR,'' referred to in 
section 9.1.1 of ANSI/ASHRAE 118.1-2012 is the flow rate of water 
through the CHPWH expressed in gallons per minute obtained after 
following the steps in section 5.2 of this appendix. Use the evaporator 
side rating conditions specified in section 4.6 of this appendix to 
conduct the test as per section 9.1.1 of ANSI/ASHRAE 118.1-2012.
    5.4. Calculate the COPh of the CHPWH according to 
section 10.3.1 of the ANSI/ASHRAE 118.1-2012 for the ``Full Capacity 
Test Method.'' For all calculations, time differences must be expressed 
in minutes.

[FR Doc. 2016-26211 Filed 11-9-16; 8:45 am]
 BILLING CODE 6450-01-P