[Federal Register Volume 62, Number 85 (Friday, May 2, 1997)]
[Proposed Rules]
[Pages 24164-24209]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-10922]



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Part II





Department of Energy





_______________________________________________________________________



Office of Energy Efficiency and Renewable Energy



_______________________________________________________________________



10 CFR Part 435



Energy Efficiency Code For New Federal Residential Buildings; Proposed 
Rule

  Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed 
Rules  

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DEPARTMENT OF ENERGY

Office of Energy Efficiency and Renewable Energy

10 CFR Part 435

[Docket No. EE-RM-96-300]
RIN 1904-AA53


Energy Efficiency Code for New Federal Residential Buildings

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

ACTION: Notice of proposed rulemaking, public hearing, and request for 
public comment.

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SUMMARY: The Department of Energy today proposes a rule that would 
establish minimum energy-efficiency building standards for new Federal 
residential buildings, including single-family and multi-family low-
rise housing, pursuant to the requirements of the Energy Conservation 
and Production Act of 1976, as amended. The proposed rule would cover 
all aspects of residential building thermal envelopes, including 
foundations, crawl spaces, floors, walls, fenestration, roof/ceilings, 
and attics. The proposed rule would also cover the heating, 
ventilation, and air-conditioning systems design, service water heating 
systems, radon control, air infiltration, and electrical power and 
lighting systems. The proposed rule would revise the current Federal 
residential standards to conform generally with the format and language 
of the Council of American Building Officials Model Energy Code, 1992. 
The proposed rule is, on the average, 11 percent more energy-efficient 
than the Model Energy Code, 1992 for single-family residences and 26 
percent more energy-efficient than the Model Energy Code, 1992 for 
multi-family residences for heating and cooling.

DATES: Written comments on the proposed rule (ten copies and, if 
possible, a computer disk containing the electronic file of these 
comments) must be received on or before July 14, 1997. A public hearing 
will be held in Washington, D.C., on June 5, 1997, beginning at 9:30 
a.m. at the address listed below. Requests to speak must be received by 
the Department on or before June 3, 1997. Ten copies of the statement 
to be given at the public hearing must be received by the Department by 
4:00 p.m., June 3, 1997.

ADDRESSES: Written comments on the proposed rule (ten copies), as well 
as requests to speak at the public hearing, requests for copies of the 
technical support documents and requests for speaker lists should be 
addressed to: U.S. Department of Energy, Energy Efficiency Code for 
Federal Residential Buildings, Docket Number EE-RM-96-300, Office of 
Codes and Standards, Office of Energy Efficiency and Renewable Energy, 
U.S. Department of Energy, Room 1J-018, 1000 Independence Avenue, S.W., 
Washington, D.C. 20585-0121, (202) 586-7574.
    Fax comments will not be accepted. The public hearing will be held 
at the U.S. Department of Energy, Forrestal Building, Room 1E-245, 1000 
Independence Avenue, S.W., Washington D.C. 20585-0121. Copies of the 
transcripts of the public hearings and written public comments received 
may be read at the Department of Energy's Freedom of Information 
Reading Room, U.S. Department of Energy, Forrestal Building, Room 1E-
190, 1000 Independence Avenue, S.W., Washington, D.C. 20585-0121, (202) 
586-6020, between the hours of 9:00 a.m. and 4:00 p.m., Monday through 
Friday, except Federal holidays. The reference standards are also 
available from the sources listed in Subpart H of the proposed rule. 
For more information concerning public participation see section IX. 
Public Comment Procedures.

FOR FURTHER INFORMATION CONTACT:

Stephen P. Walder, Office of Codes and Standards, EE-43, U.S. 
Department of Energy, Office of Energy Efficiency and Renewable Energy, 
Room 1J-018, 1000 Independence Avenue, S.W., Washington, D.C. 20585-
0121, (202) 586-9209;

Francine B. Pinto, Esq., Office of General Counsel, GC-72, U.S. 
Department of Energy, Room 6E-042, 1000 Independence Avenue, S.W., 
Washington, D.C. 20585-0103, (202) 586-7432.

SUPPLEMENTARY INFORMATION:

I. Introduction

A. Authority
B. Background
    1. Model Energy Code, 1992
    2. The Current Federal Standards
    3. Standard 90.2-1993

II. Relationship Between the Proposed Rule, the MEC, 1992, the Current 
Federal Residential Standards, Standard 90.2-1993, and Other Federal 
Initiatives

A. General
B. Relationship Between the Proposed Rule and the MEC, 1992
C. Relationship Between the Proposed Rule and the Current Federal 
Residential Standards
D. Relationship Between the Proposed Rule and Standard 90.2-1993
E. Relationship to Other Federal Initiatives

III. Description of the Proposed Rule and Differences Between the 
Proposed Rule and the Model Energy Code, 1992

A. Subpart A: Administration and Enforcement
    1. Sections 435.102.1.2 and 435.102.1.3: Building Envelope 
Insulation and Insulation Installation
    2. Section 435.102.3: Fenestration Product Rating, 
Certification, and Labeling
    3. Section 435.104: [Reserved]
    4. Section 435.105: [Reserved]
    5. Section 435.106: [Reserved]
    6. Section 435.107: Precedence
    7. Section 435.108: Life-Cycle Cost Analysis
B. Subpart B: Definitions
C. Subpart C: Design Conditions
D. Subpart D: Design by Systems Analysis; Design Utilizing Renewable 
Energy Sources
    1. Section 435.402.1: Energy Analysis
    2. Section 435.402.1.1: Input Values/Assumptions for Group R 
(Single Family and Multi-family Low Rise) Buildings
    3. Section 435.403.3: Passive Solar Design Analysis
E. Subpart E: Design by Component Performance Approach
    1. Major Revisions from the Model Energy Code, 1992 that are 
Contained in Subpart E of the Proposed Rule
    a. Section 435.502: Building Thermal Envelope Requirements
    b. Section 435.502.2.1.1.2: Metal Framing
    c. Section 435.502.2.1.5: Crawl Space Walls
    d. Section 435.502.3.3: Recessed Lighting Fixtures
    e. Section 435.503.2: Mechanical Equipment Efficiency
    f. Section 435.503.3.1.1: Heating and Cooling Equipment Capacity
    g. Section 435.503.5.7.2: Duct Sealing
    h. Section 435.503.5.9.1: Backdrafting Test
    i. Section 435.504.2: Service Water Heating Equipment
    j. Section 435.504.4: Heat Traps
    2. Miscellaneous Revisions that are Contained in Subpart E of 
the Proposed Rule, Not in the MEC, 1992
F. Subpart F: [Reserved]
G. Subpart G: Radon Control
H. Subpart H: Standards

IV. Consultation

V. Energy and Economic Impacts

VI. Technological Feasibility and Economic Justification

VII. Measures Concerning Radon and Other Indoor Air Pollutants

VIII. Findings and Certification

A. Review Under the National Environmental Policy Act
B. Environmental Protection Agency Review
C. Regulatory Planning and Review
D. Federalism Review
E. Review Under Executive Order on Metric Usage in Federal 
Government Programs
F. Review Under Executive Order on Civil Justice Reform
G. Review Under the Regulatory Flexibility Act
H. Paperwork Reduction Act Review

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I. Review Under Section 32 of the Federal Energy Administration 
Authorization Act
J. Unfunded Mandates Reform Act Review

IX. Public Comment Procedures

A. Participation in Rulemaking
B. Solicitation of Public Comments
C. Written Comment Procedures
D. Public Hearings
    1. Procedure for Submitting Requests to Speak
    2. Conduct of Hearings



I. Introduction

A. Authority

    The Department today proposes a rule that would establish Federal 
building energy-efficiency standards for new Federal residential 
buildings pursuant to section 305(a) of the Energy Conservation and 
Production Act (ECPA), as amended by the Energy Policy Act of 1992 
(EPACT), 42 U.S.C. 6834(a). In developing this proposed rule, the 
Department is directed to consult with other Federal agencies as well 
as private and state associations and other appropriate persons.
    Section 305(a)(1) of the ECPA requires the Department to establish 
Federal building energy standards that include those energy-efficiency 
measures that are technologically feasible and economically justified. 
The standards must contain energy saving and renewable energy 
specifications that meet or exceed the energy saving and renewable 
energy specifications of the Council of American Building Officials 
(CABO) Model Energy Code (MEC), 1992. Section 305(a)(2)(A).
    Section 305(a)(2)(B) requires that to the extent practicable, the 
proposed standards use the same format as the appropriate voluntary 
building energy code, in this case, the MEC, 1992. Furthermore, Section 
305(a)(2)(C) requires that the proposed rule be established in 
consultation with the Environmental Protection Agency (EPA) and other 
Federal agencies and, where appropriate, contain measures with regard 
to radon and other indoor air pollutants.
    The current energy performance standards for new Federal buildings 
remain in effect until the standards established under subsection (a) 
become effective. Section 305(d). These current standards are found in 
10 CFR Part 435, Subpart C.
    Section 306 addresses Federal compliance. Each Federal agency and 
the Architect of the Capitol must adopt procedures to assure that new 
Federal buildings will meet or exceed the Federal building energy 
standards proposed here. Section 306(a). Section 306(b) bars the head 
of a Federal agency from expending Federal funds for the construction 
of a new Federal building unless the building meets or exceeds the 
appropriate Federal building energy standards established under Section 
305.

B. Background

    There are currently three building energy codes that address low-
rise residential buildings in all parts of the United States \1\: the 
Model Energy Code (MEC); 10 CFR Part 435, Subpart C, Mandatory 
Performance Standards for New Federal Residential Buildings; and the 
American Society of Heating, Refrigerating and Air Conditioning 
Engineers (ASHRAE), Inc., Standard 90.2-1993, Energy-Efficient Design 
of New Low-Rise Residential Buildings. All three bear on today's 
proposed rule. The MEC contributes format, substance, and technical 
improvements to the proposal. The Federal residential standards first 
introduced the concept of cost-effectiveness in building standards and 
tools to analyze the economic justification of energy-efficiency 
requirements in building standards. Tools that evolved from the 
development of the current Federal residential standards were used to 
determine the economic justification for the requirements contained in 
the proposed rule. ASHRAE Standard 90.2-1993 also provides substantive 
technical improvements to the proposal.
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    \1\ There are other building energy codes that are state-
specific or regional that are not considered.
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1. Model Energy Code, 1992
    Currently, the MEC is the most widely accepted and used residential 
energy-efficiency code in the United States. Seventeen states have 
adopted the MEC, or modified versions of the MEC, as their energy code. 
Approximately 20 percent of new home loans are issued or guaranteed by 
the Department of Housing and Urban Development, the Department of 
Veterans Affairs, and the Rural Economic and Community Development 
group of the Department of Agriculture. Such loans or loan guarantees 
require compliance with the MEC, 1992. The MEC has been promulgated 
jointly by the three model code organizations: the Building Officials 
and Code Administrators International; the International Conference of 
Building Officials; and the Southern Building Code Congress 
International under the auspices of the Council of American Building 
Officials. The MEC is provided as a model and intended for adoption by 
state and local jurisdictions.
    The provisions of the MEC, 1992 regulate the design of building 
envelopes for adequate thermal resistance and low air leakage and the 
design and selection of mechanical, electrical, service water-heating 
and illumination systems and equipment which will enable effective use 
of energy in new building construction. The MEC provides flexibility to 
permit the use of innovative approaches and techniques to achieve 
efficient utilization of energy. These provisions are structured to 
permit compliance with the intent of the code by any one of the 
following paths of design: (1) A systems analysis approach for the 
entire residential building and its energy-using subsystems, including 
buildings which utilize renewable sources (Chapter 4), (2) a building 
design by component performance approach (Chapter 5) and, (3) building 
design by acceptable practice (Chapter 6).

2. The Current Federal Standards
    On August 25, 1988, the Department published standards for new 
Federal residential buildings (53 FR 32536). It established building 
energy-efficiency standards for the design and construction of Federal 
residential buildings.
    The current Federal standards require that Federal agencies use 
software to create project-specific compliance forms that are then 
completed by prospective builders to demonstrate compliance with 
minimum energy-efficiency requirements. The process must be undertaken 
for each project. The micro-computer software program, Conservation 
Optimization Standard for Savings in Federal Residences (COSTSAFR), 
uses local construction, maintenance and replacement costs, local 
climate data, and local fuel costs to determine an energy-efficient and 
cost-effective energy usage goal for any of nine residential building 
unit types addressed in the COSTSAFR program data base. COSTSAFR 
calculates project-specific minimum energy-efficiency requirements and 
presents these requirements in compliance forms known as ``the point 
system.'' The use of COSTSAFR eliminated the need for performing 
lengthy calculations or making uninformed choices regarding the 
selection of energy-efficiency measures. COSTSAFR is designed so that 
implementing officials, designers, and builders can easily tell if a 
proposed combination of measures will result in energy-efficiency 
levels that meet or

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exceed the COSTSAFR required level for cost-effective energy-efficiency 
in a building.
    The Department decided not to use COSTSAFR as the basis for this 
new Federal proposed rule because it cannot always be assured of 
complying with the new legislative requirements. In particular, 
COSTSAFR can generate energy-efficiency requirements that do not meet 
the MEC, 1992 energy-efficient levels specified by EPACT. The software 
would have to be reconfigured to eliminate this possibility.
3. Standard 90.2-1993
    Standard 90.2-1993, Energy-Efficient Design of New Low-Rise 
Residential Buildings, is a standard for residential construction 
published by the American Society of Heating, Refrigerating and Air 
Conditioning Engineers (ASHRAE), Inc. Standard 90.2-1993 is the next 
generation residential component of ASHRAE's earlier Standard 90 (1975) 
and Standard 90A-1980, which specified design requirements for energy-
efficient commercial and residential buildings. Standard 90.2-1993 sets 
criteria for the building envelope, heating equipment and systems, air-
conditioning and systems, and provisions for overall building design 
alternatives and trade-offs.

II. Relationship Between the Proposed Rule, the MEC, 1992, the Current 
Federal Residential Standards, Standard 90.2-1993, and Other Federal 
Initiatives

A. General

    The Department has decided to develop a proposed rule similar in 
format to the MEC rather than modify the current Federal residential 
building standards. Currently, construction professionals are more 
familiar with the MEC, 1992 format and content than the Federal 
standards. This familiarity with the MEC requirements and format is 
likely to reduce costs associated with the development and use of 
building specifications consistent with those of the MEC. The 
consistency of the proposed rule with industry-wide practice will 
facilitate implementation by Federal agencies of the final rule. 
Currently, 10 CFR Part 435 contains standards for Federal commercial 
buildings (Subpart A), a reserved section that was intended for 
voluntary standards for new non-Federal residential buildings (Subpart 
B), and standards for Federal residential buildings (Subpart C). On 
August 6, 1996, the Department proposed to remove Subpart A from Part 
435 and republish it as a new Part 434 in the Code of Federal 
Regulations. (61 FR 40882). In today's proposed rule, Subparts B and C 
would be removed and Part 435 would be revised to establish standards 
for Federal residential buildings only.

B. Relationship Between the Proposed Rule and the MEC, 1992

    The proposed rule would adopt portions of the Model Energy Code, 
1992 verbatim. There are, however, some requirements in the proposed 
rule that exceed the MEC, 1992 resulting in increased energy-
efficiency. Many of the provisions improving energy-efficiency are 
found in the 1993 and 1995 versions or the 1994 amendments to the MEC, 
1993. Those aspects of the proposed rule that exceed the MEC, 1992 
resulting in increased energy-efficiency are: (1) more stringent 
thermal envelope requirements, (2) insulating of crawl space walls, (3) 
sealing recessed light fixtures, (4) heating and cooling equipment 
capacity requirements, (5) air distribution system construction, and 
(6) heat traps.
    The proposed rule would also make revisions to the Model Energy 
Code, 1992, that are consistent with current building construction 
practice. These include requirements for: (1) insulation inspection, 
(2) window and door thermal performance ratings, (3) improved 
performance path specifications, (4) metal framing construction and, 
(5) radon and other indoor air pollutants. The requirements referenced 
in (1)-(4) above, do not save energy but help ensure that energy 
savings are achieved. Requirements concerning radon and other indoor 
air pollutants are consistent with health and safety needs.
    Further, the Department has made miscellaneous minor changes to the 
MEC, 1992 to improve the clarity and useability of the rule. These 
miscellaneous changes are not expected to have any impact on the 
agencies or their contractors.
    The proposed rule is on the average, 11 percent more energy-
efficient than the Model Energy Code, 1992 for single-family residences 
and 26 percent more energy-efficient than the Model Energy Code, 1992 
for multi-family residences for heating and cooling.

C. Relationship Between the Proposed Rule and the Current Federal 
Residential Standards

    There are significant differences and similarities between the 
proposed rule and the current standards. The current standards have a 
point system related to energy cost that permits tradeoffs among 
energy-efficiency measures, while the proposed rule has an overall U-
value that permits tradeoffs in envelope measures. The use of 
microcomputer software is necessary to determine the requirements of 
the current standards, whereas, the requirements of the proposed rule 
are contained in a hardcopy publication. Both have a similar whole 
building energy usage analysis compliance approach.
    The current Federal standards will not always assure the user of 
meeting or exceeding the requirements of the MEC, 1992. The Department 
has demonstrated that residential buildings designed using COSTSAFR 
will have a less stringent level of thermal performance than those 
buildings designed using the requirements of the proposed rule.

D. Relationship Between the Proposed Rule and Standard 90.2-1993

    A number of features from Standard 90.2-1993 are included in 
today's proposed rule. These provisions address feasible residential 
design features not presently or adequately addressed by the MEC, while 
providing the potential for further energy savings in the proposed 
rule. They include heating and cooling equipment sizing limitations; 
default thermal performance data for metal frame walls; and heat traps 
on water heaters for potable water.
    Standard 90.2-1993 has been put into code format providing a 
similar structure for both the standard and the proposed rule. Both 
also have three alternative compliance paths of similar nature. 
Standard 90.2-1993 however, has more complexity than the respective 
compliance options of the proposed rule. The Department believes that 
this greater complexity of Standard 90.2-1993 would make it more 
difficult to adopt, use, and enforce than the MEC, which is the basis 
for the proposed rule. The Department also believes that the complexity 
and differences between Standard 90.2-1993 and the MEC would have made 
it difficult for the Department to have assured the user of meeting the 
minimum energy-efficiency requirements of the MEC, 1992. The Department 
determined that the necessary cost and resources to revise Standard 
90.2-1993 as the proposed Federal residential rule and that would meet 
or exceed the MEC, 1992 would not be warranted. The proposed rule looks 
to the broad recognition and penetration enjoyed by the MEC within the 
community of residential designers, builders and enforcement officials 
to facilitate its implementation by the Federal sector.

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E. Relationship to Other Federal Initiatives

    The proposed rule would establish the minimum level of energy-
efficiency for new Federal buildings. The rule works in conjunction 
with two related Federal initiatives designed to encourage cost-
effective efficiency improvements for new buildings beyond the minimum 
requirements of the proposed rule. First, Executive Order on Energy 
Efficiency and Water Conservation at Federal Facilities, Executive 
Order No. 12902 (59 FR 11463, March 8, 1994), specifically requires 
that, ``Each agency involved in the construction of a new facility--
shall: (1) design and construct such facility to minimize the life 
cycle cost of the facility by utilizing energy efficiency, water 
conservation, or solar or other renewable energy technologies.'' 
Section 306(a) of Executive Order 12902. It also requires agencies to 
``ensure that the design and construction of facilities meet or exceed 
the energy performance standards applicable to Federal residential or 
commercial buildings as set forth in 10 CFR Part 435, local building 
standards, or a Btu-per-gross square-foot ceiling--whichever will 
result in a lower life cycle cost over the life of the facility.'' 
Section 306(a)(2) of Executive Order 12902. In addition, Federal 
agencies shall increase, to the extent practicable and cost-effective, 
purchases of products that are in the upper 25 percent of energy 
efficiency for all similar products, or products that are at least 10 
percent more efficient than the minimum level that meets Federal 
standards. Section 507(a)(2) of Executive Order 12902. This latter 
provision is being implemented through the Department's ``Procurement 
Challenge Program'' that notifies Federal agencies of the availability 
and performance of these high-efficiency options. This ``Procurement 
Challenge Program'' is being coordinated with the EPA ``Energy Star'' 
product specification activities. In addition, the Department's Office 
of Building Technologies, State and Community Programs provides 
detailed technical information on state-of-the-art energy-efficiency 
equipment for new buildings. These sources of technical assistance can 
help Federal agencies specify highly-efficient equipment for new 
Federal residential buildings.
    Second, section 435.108 of today's proposed rule references the 
requirements of 10 CFR Part 436 governing life-cycle cost analysis for 
Federal energy investments. The life-cycle cost analysis provisions 
found in 10 CFR Part 436 allow agencies to determine when additional or 
alternate energy-efficiency measures would provide net benefits in the 
form of energy cost savings to ensure that measures selected are cost-
effective to the Federal government. This is especially relevant in 
areas where energy costs are higher than presumed for the analysis 
supporting today's proposal, and for innovative technologies and 
specifications that cannot be readily incorporated into the proposed 
rule. The microcomputer program entitled ``ARES'' (Automated 
Residential Energy Standard) can be used for evaluating the life-cycle 
cost-effectiveness of various thermal envelope energy-efficiency 
measures (EEMs) that can be more energy-efficient than the requirements 
of the proposed rule. The Department is currently conducting life-cycle 
cost analysis that would identify energy-efficiency measures that are 
economically justified in specified circumstances and exceed the 
minimum requirements of the proposed rule. The Department will provide 
the results of this analysis to the Federal agencies to assist them in 
the design and construction of energy-efficient Federal residential 
buildings.

III. Description of the Proposed Rule and Differences Between the 
Proposed Rule and the Model Energy Code, 1992

    This section describes the proposed rule and the differences 
between the proposed rule and the Model Energy Code, 1992. Those 
sections of the proposed rule not specifically addressed here have been 
adopted from the MEC, 1992. Minor language and citation changes will 
not be noted. The discussion below corresponds to the subparts, 
sections, paragraphs, and subparagraphs in the proposed rule. The 
sections identified as reserved are discussed briefly.

A. Subpart A: Administration and Enforcement

    This subpart describes the scope and general requirements of the 
rule, the requirements concerning the identification and maintenance 
information on building materials and equipment, the use of alternate 
materials, the application of the proposed rule if sections are in 
conflict, and the requirement for a life-cycle cost analysis.
    Proposed sections 435.101-108 contain changes from the MEC, 1992, 
as discussed below. The Department believes that the provisions 
discussed below are technologically feasible, and are of such minimal 
cost that the benefits of such requirements make them economically 
justified.
1. Sections 435.102.1.2 and 435.102.1.3: Building Envelope Insulation 
and Insulation Installation
    The sections require that insulation installed in the building be 
clearly marked so that the ``R-value'' of the insulation can be easily 
verified. The blown or sprayed attic insulation ``depth'' marker 
requirement is contained in the MEC, 1995 but not in the MEC, 1992. The 
insulation depth markers will help ensure that the claimed thickness of 
the loose-fill ceiling insulation can be verified. Verification of the 
ceiling insulation assures that the designed energy-efficiency 
performance of the building ceiling can be achieved at a minimal cost 
to the government. The associated costs are minimal compared to the 
possibility of installing insulation that is less than the required 
designed thickness and thereby loses energy. The use of depth markers 
is technologically feasible because a marker is a simple ruler 
graduated in one-inch increments and affixed to the roof/ceiling 
framing.
2. Section 435.102.3: Fenestration Product Rating, Certification, and 
Labeling
    Section 121 of EPACT requires the Secretary of Energy to make a 
determination, within one year of enactment, on whether a window energy 
rating and labeling program established by the National Fenestration 
Rating Council (NFRC) meets the objectives of the legislation. If not, 
the Department is to develop a mandatory rating program. The 
Secretary's provisional determination concluded that the NFRC voluntary 
national window rating program meets the requirements of EPACT. 
(September 23, 1994, 59 FR 48865, 48868). The Department supports the 
NFRC efforts to establish a uniform, national rating, certification and 
labeling program through incorporation of the NFRC program in Federal, 
state and local government and national voluntary codes and standards.
    The verification of window and door assembly U-values is a 
significant element in determining the overall U-value or thermal 
performance of the building envelope, which is a key factor in 
achieving compliance with the proposed rule. Section 435.102.3 of the 
proposed rule requires that when Federal agencies purchase fenestration 
products, the U-value (conductive heat transfer) for that fenestration 
product (window, door, and skylight) shall be assigned. If the product 
has been tested in accordance with NFRC 100-91 (Procedure for 
Determining Fenestration

[[Page 24168]]

Product Thermal Properties), the NFRC U-value shall be used. The rating 
procedure tests the fenestration products to determine the conductive 
heat transfer properties and/or characteristics of the product.
    If fenestration products are not tested in accordance with NFRC 
100-91, a default U-value will be assigned, using Tables 102.3.1 and 
102.3.2 located in the Appendix of the proposed rule. The default 
values represent a conservative energy-efficiency performance potential 
of a product based on characteristics of the product which are 
verifiable by visual inspection. The NFRC 100-91 rating procedure and 
the default U-value tables for non-tested products in the proposed rule 
are those found in the MEC, 1995.
    There is no standard for rating the energy-efficiency (U-values) of 
window and door assemblies in the MEC, 1992. The inclusion of the 
requirement to assign U-values to fenestration products will 
potentially save energy costs by eliminating inaccurate U-values or 
ratings that do not reflect the total window or door assembly thermal 
performance. Thus assigning U-values or default U-values helps to 
ensure that the claimed thermal performance of fenestration products 
will actually be achieved in housing construction.
    The NFRC procedure provides a fair and accurate rating of window 
and door thermal performance. Over 22,000 products have been rated by 
the NFRC. The ratings of window and door thermal performance are 
recognized by at least six states in their building code provisions 
regarding energy-efficiency.
    Windows and doors that are rated in accordance with NFRC 100-91 may 
result in an expenditure by the product manufacturer. However, NFRC 
100-91 is set up so that every window or door unit need not be tested 
individually. The results of a few actual tests are extrapolated by 
computer modeling to the manufacturer's entire product line. Thus the 
per unit cost of receiving a NFRC rating is relatively small. 
Alternatively, a fenestration product manufacturer can elect not to 
test and save the associated costs, and receive the default U-value 
rating.
    Assigning a U-value according to the new rating procedure can 
change the rating received by particular windows. A model that was 
previously rated at 0.4 might, for example, be rated under the new 
system at 0.5. As a result, there may be situations in which agencies 
would change the window selected in order to keep with the code's U-
value requirements. That change could result in higher purchase prices, 
but would reduce building energy use as well. The use of energy-
efficient windows is becoming standard building construction practice 
in most regions of the nation, particularly in the northern tier 
states, indicating their general cost-effectiveness in today's building 
markets. Given the nominal cost per unit for NFRC testing and rating 
and the general cost-effectiveness of energy-efficient windows, the 
Department has determined that the assigning of U-values in accordance 
with NFRC 100-91 or default U-values in the proposed rule is 
economically justified. See the Technical Support Document, section 
6.7, page 6.6.
3. Section 435.104: [Reserved]
    The proposed rule does not include the section entitled, ``Plans 
and Specifications'' from the MEC, 1992.
4. Section 435.105: [Reserved]
    The MEC, 1992 has requirements concerning the inspection by the 
building official of construction or work for which a building permit 
is required. Federal agencies have various procedures concerning the 
inspection of construction. Section 435.105 is reserved in the proposed 
rule to allow Federal agencies the flexibility of using their own 
requirements concerning the inspection of residential construction.
5. Section 435.106: [Reserved]
    The proposed rule does not include the section entitled, 
``Validity'' from the MEC, 1992.
6. Section 435.107: Precedence
    The Model Energy Code, 1992 contains no statement addressing the 
order of precedence between potentially conflicting requirements of the 
proposed code and those of a reference standard. Section 435.107.1 of 
the proposed rule clarifies which requirements that shall apply.
7. Section 435.108: Life-Cycle Cost Analysis
    The MEC, 1992 contains no requirements related to life-cycle costs. 
The proposed rule would require building design(s) of Federal 
residential buildings to be evaluated consistent with Subpart A of 10 
CFR Part 436, which specifies methodologies and procedures for life-
cycle cost analyses of Federal buildings.

B. Subpart B: Definitions

    This subpart includes definitions for all relevant words or phrases 
that have a specific meaning within the context of the rule. In 
accordance with the proposed rule, new definitions not in the MEC, 1992 
have been added and unneeded definitions have been removed. For 
example, definitions related to the radon control requirements have 
been added and definitions related to non-residential HVAC systems and 
components not regulated by this rule have been deleted. Appendix D in 
the Technical Support Document identifies those definitions that have 
been added or removed.

C. Subpart C: Design Conditions

    This subpart gives sources for heating and cooling degree-day data, 
establishes design conditions for the sizing of the heating, 
ventilating, and air-conditioning system, and provides reference 
standards for mechanical ventilation criteria. Other than identifying 
cooling degree-days and providing more specific information on where 
one may obtain weather data, this section is unchanged from the MEC, 
1992.

D. Subpart D: Design by Systems Analysis; Design Utilizing Renewable 
Energy Sources

    This subpart contains a compliance approach that may be used as an 
alternative to Subpart E. Subpart E contains the minimum energy-
efficiency requirements for the thermal performance of new Federal 
residential buildings.
    Subpart D requires that the user conduct an annual energy analysis. 
It defines the general methodology and rules for this energy 
comparison. A proposed building complies with this rule if its 
calculated annual energy usage is less than or equal to the energy 
usage of a similar building (referred to as the ``standard design'') 
designed in accordance with Subpart E. The annual energy analysis 
methodology is equivalent to that in Chapter 4 of MEC, 1992 but 
provides more direction and specific detail on how the annual energy 
analysis shall be conducted, as discussed below.
1. Section 435.402.1: Energy Analysis
    A critical parameter for performing any comparative energy analysis 
is defining the space heating, air conditioning, and service water 
heating equipment and the efficiency or performance levels of that 
equipment for the ``standard'' design.
    As in the MEC, 1992, the proposed rule would require that the 
standard and the proposed design be compared utilizing the ``same 
energy source(s) for the same functions.'' These energy sources are 
determined by the Subpart E provisions governing the selection of 
equipment. This energy consumption provision is similar to the 
provision in

[[Page 24169]]

section 402.1 contained in the MEC, 1992 and 1993. The only substantive 
difference between the proposed rule and the earlier versions of the 
MEC that relate to this section is the application of life-cycle cost 
requirements.
    In order to comply with Subpart D, a proposed design must be at 
least as life-cycle cost-effective as the standard design and use no 
more energy than the standard design. In the event that the proposed 
design utilizes more than one energy source and increases the 
consumption of one energy source and decreases the consumption of the 
other energy source, then the overall energy consumption, measured at 
the site, must be less than or equal to the standard design. Because 
the energy sources in the standard and proposed design must be the 
same, changes in energy consumption that affect more than one energy 
source would be limited to variations in equipment efficiency and types 
and building thermal envelope efficiencies.
    Because methods for consistently measuring and comparing the energy 
performance of new technologies take time to develop, the proposed 
design may utilize newer equipment types not covered using current 
Department test procedures. The Department is requesting comment on 
methods of addressing newer equipment technologies for which a 
recognized means of evaluating and comparing energy performance have 
not yet been fully developed.
2. Section 435.402.1.1: Input Values/Assumptions for Group R (Single-
Family and Multi-family Low Rise) Buildings
    This proposed rule specifies input values/assumptions for certain 
energy-related building parameters that must be used in the whole 
building energy analysis comparison. These values were taken from the 
MEC, 1995. In contrast, the MEC, 1992 does not provide specification of 
these values. For example, if the builder or designer chooses to use 
the annual energy analysis approach, the thermostat set points that 
must be assumed are given in Table 402.1.1-4, whereas the MEC, 1992 
provides no information.
    The specification of input values/assumptions performs two 
functions. First, it eliminates the time and effort that each user 
needs to set these values/assumptions individually. Second, it 
establishes ground rules that ensure consistency among different whole 
building annual energy analyses and helps prevent misuse of this 
approach.
    The Department has determined that specifying the input values/
assumptions to annual energy analyses comparisons is technologically 
feasible because it is consistent with current building energy usage 
analysis practice and is the only way to verify consistency in 
analytical results across the different analytical tools. The 
specification of input values is also economically justified since 
failure to specify such input values could result in the approval of 
noncomplying or unrealistic building designs and unnecessary energy 
cost increases. The introduction of erroneous data would add 
unwarranted time, effort, and cost to the project.
    The Department has included many new annual energy analysis input 
values/assumptions in the proposed rule. See the Technical Support 
Document, section 6.8, page 6.8.
3. Section 435.403.3: Passive Solar Design Analysis
    The MEC, 1992 and 1995 do not include direction on methodologies 
for measuring the energy impacts of solar space conditioning. This 
section of the proposed rule allows for the optional use of 
``BuilderGuide,'' a software program that calculates heating and 
cooling loads for solar technologies. ``BuilderGuide'' was produced by 
the Department in partnership with the Passive Solar Industries Council 
and the National Renewable Energy Laboratory. The resulting 
``BuilderGuide'' package is specific to some 2400 United States 
locations, and uses a methodology that is based on 15 years of solar 
energy research. The Department has determined that ``BuilderGuide'' is 
a well developed, widely distributed and recognized software program. 
Other reliable tools for calculating energy usage of solar technologies 
or other new energy-efficiency measures can be used. The Department 
recognizes that designs using renewable energy sources for space 
conditioning or water heating may be economically justified. The 
Department is promoting ways to further stimulate the use of renewable 
sources of energy. The Department welcomes additional suggestions on 
approaches for crediting measures that use renewable sources of energy.

E. Subpart E: Design by Component Performance Approach

    Sections 435.501-505 contain the minimum energy-efficiency 
requirements for the thermal performance of building envelope 
components, building mechanical systems and equipment, service water 
heating, and electrical power and lighting. Compliance with the 
requirements of Subpart E is required unless the optional compliance 
approach prescribed in Subpart D is used.
    The building envelope requirements apply to the building components 
enclosing conditioned space, including: roof/ceilings, above grade 
walls, slab-on-grade floors, floors over unconditioned spaces, basement 
walls, crawl space walls, doors, windows, and skylights. The proposed 
rule also contains requirements limiting air infiltration through the 
building envelope.
    The mechanical systems and equipment performance requirements set 
heating and cooling equipment load capacity (sizing) limits, 
temperature and humidity control requirements, distribution system 
construction and insulation requirements, and backdrafting testing 
requirements. The requirements relating to electrical power and 
lighting systems apply only to multi-family residences. The mechanical 
equipment section does not require mechanical equipment efficiencies 
that exceed current Federal minimum standards.
    Sections 435.501-505 of the proposed rule in Subpart E revise and 
update the requirements contained in Chapter 5 of the MEC, 1992. 
Subpart E contains two separate building envelope compliance 
approaches. The two approaches are: (1) The individual component 
performance approach and, (2) the whole building performance approach. 
The individual component performance approach (section 435.502.2.1) 
gives maximum U02 requirements for the floor over 
unheated spaces, wall, and roof/ceiling. The different elements of the 
wall (insulation, windows, doors, opaque wall), the floor (insulation, 
type of floor), or the roof/ceiling (insulation, skylights, type of 
ceiling) may be varied to achieve the U0. The whole building 
performance approach (section 435.502.2.2) defines the maximum 
U0 requirement for the entire building. The user can then 
tradeoff among the requirements for the walls, floors, and roof/
ceilings as long as the maximum U0 for the entire building 
is not exceeded.
---------------------------------------------------------------------------

    \2\U0 = the area-weighted average thermal 
transmittance of an area of the building envelope; i.e., the 
exterior wall assembly including fenestration and doors, the roof 
and ceiling assembly, and the floor assembly (British thermal unit/
(hour x square feet x degrees Fahrenheit).
---------------------------------------------------------------------------

1. Major Revisions From the Model Energy Code, 1992 That Are Contained 
in Subpart E of the Proposed Rule
    The major substantive changes from the MEC, 1992 as found in 
Subpart E are described below.
    a. Section 435.502: Building thermal envelope requirements. The 
tables

[[Page 24170]]

found in proposed section 435.502, and Figures 1 through 6 in the 
Appendix contain the building thermal envelope requirements. These 
requirements are significantly changed from the MEC, 1992 and generally 
are more stringent than the MEC, 1992, except for the requirements for 
crawl space walls which are essentially the same as those in the MEC, 
1992. The requirements that are more stringent than the MEC, 1992 
consist of maximum U0-values for above-grade walls including 
windows and doors, roof/ceilings, floors over unheated spaces, basement 
walls, and minimum R-values for slab-on-grade perimeters. When 
describing the thermal performance of a building component, consider 
that the lower a U0-value, the more energy-efficient the 
component and the higher a R-value, the more energy-efficient the 
component.
    The Department conducted a life-cycle cost economic analysis, as 
specified at 10 CFR Part 436, to analyze these thermal envelope 
requirements so as to minimize life-cycle costs to the Federal 
government. The assessment was conducted using the ARES computer 
software analyzing information such as the average Federal cost of 
energy, expected energy price increases, and typical costs for 
installation and maintenance of proposed measures. The economic 
analysis considered construction-related costs and space heating and 
cooling energy costs for 881 cities and eight types of common heating 
fuel/equipment types. See the Technical Support Document (chapters 2 
thru 5) for a detailed description of the analysis to establish the 
building thermal envelope requirements.
    b. Section 435.502.2.1.1.2: Metal framing. The proposed rule 
includes a detailed new table (Appendix Table 502.2.1.1.2) to provide 
users with the correction factors for the thermal-performance values of 
wall assemblies framed with metal studs. Table 502.2.1.1.2 does not 
appear in the MEC, 1992 but is in the MEC, 1995 and Standard 90.2-1993. 
This table provides a standardized treatment of heat loss through walls 
framed with metal studs. The thermal performance requirements of such 
walls are the same as those for wood-framed walls. Metal framing is 
technologically feasible. Metal wall assemblies have become more 
popular over the last several years due in part to the price increase 
of wood. Metal framing is not required by the rule and need not be 
specified where not cost-effective or otherwise not preferred.
    c. Section 435.502.2.1.5: Crawl space walls. Section 435.502.2.1.5 
of the proposed rule requires floors above crawl spaces vented to 
outdoors to be insulated. This requirement is contained in the MEC, 
1995, but is not in the MEC, 1992. In the MEC, 1992 insulating the 
crawl space wall was not dependent on whether the crawl space was 
ventilated. Wall insulation for vented crawl spaces is ineffective 
because outside air will enter the crawl space through the vents. 
Increased energy usage results from the uninsulated heat transfer path 
through the floor above. Crawl space wall insulation in the proposed 
rule is an option only if the crawl space is not vented. The Department 
has determined that the insulation of floors over vented crawl spaces 
is technologically feasible since it is part of current standard 
building construction practice.
    Further, the requirement is economically justified. See the 
Technical Support Document, section 6.3, page 6.2.
    d. Section 435.502.3.3: Recessed lighting fixtures. Recessed 
lighting fixtures, when installed in the building envelope, must be 
properly sealed to prevent unwanted ceiling air leakage. The 
requirement is contained in the MEC, 1995. Without this requirement, 
recessed lighting fixtures can be a significant source of energy loss 
due to air leakage into the attic space. The MEC, 1992 has no 
requirements relating specifically to recessed lighting fixtures.
    The Department has determined that the insulation and sealing of 
recessed lighting fixtures are technologically feasible. These 
practices are used in current building construction practice. The 
requirement is economically justified because the incremental cost for 
installing well-sealed recessed light fixtures is less than the cost of 
the energy that would otherwise be lost over the 25-year analysis 
period. See the Technical Support Document, section 6.6, page 6.5.
    e. Section 435.503.2: Mechanical equipment efficiency. Section 
435.503.2 addresses the selection of heating and cooling equipment with 
attention to the use of life-cycle cost principles. The primary 
difference between the MEC, 1992 and the proposed rule regarding this 
section is that the proposed rule includes provisions addressing the 
life-cycle cost of the installed equipment. The MEC, 1992 has no 
requirements concerning life-cycle cost principles. In the proposed 
rule when selecting among equipment options that are minimally 
compliant with Federal performance standards, that option with the 
lowest life-cycle cost is to be selected. The proposed rule allows for 
the selection of equipment that exceeds Federal minimum efficiency 
standards under Subpart E providing the equipment is at least as life-
cycle cost effective as equipment that is minimally compliant with 
Federal standards. Agencies are encouraged through the Procurement 
Challenge program and other Federal initiatives to consider more 
energy-efficient equipment.
    Given the large range of heating and cooling equipment types and 
efficiencies available, this section provides a simplified method for 
incorporating life-cycle cost principles into equipment selection. Two 
options are provided for: the first option requires Federal agencies to 
select the most cost-effective equipment that is minimally compliant 
with Federal standards. For central heating and cooling equipment 
systems for multi family dwellings that service multiple rather than 
individual dwelling units, minimum equipment efficiencies found in the 
codified version of ASHRAE Standard 90.1-1989 are used. This approach 
is consistent with the overall rule, which sets building envelope 
efficiency requirements at a level that is cost-effective on average 
when equipment at minimum Federal efficiency levels is used. The second 
option allows for the use of any other equipment available, provided 
that it is at least as cost-effective as the heating and cooling 
equipment identified under the first option. This second option allows 
for the use of more efficient versions of equipment that are subject to 
minimum Federal standards and would allow use of equipment, such as 
natural gas heat pumps or ground source heat pumps, that are not 
covered by the Federal standards.
    It is anticipated that for most buildings, an informal comparison 
of local costs and fuel availability will identify a few systems as the 
most likely to be the most cost-effective; these systems can then be 
compared in more detail to identify the system that has the lowest 
life-cycle cost under the first option. If any other equipment is 
preferred, a single additional calculation will establish whether it is 
more cost-effective than the system identified in the first option.
    f. Section 435.503.3.1.1: Heating and cooling equipment capacity. 
The Department has included limits on equipment capacities in section 
435.503.3.1.1 of the proposed rule. These requirements are taken from 
the codified version of Standard 90.2-1993. The MEC, 1992 has no 
requirements relating to the sizing of heating and cooling equipment. 
Oversizing of heating and cooling equipment results in increased energy 
usage since the equipment cycles on and off more frequently and, 
therefore, runs at a

[[Page 24171]]

lower average efficiency than properly sized equipment. Furthermore, 
oversized cooling equipment is less able to remove moisture from the 
air and, therefore, is less able to control humidity. Also, oversized 
heating, ventilating, and air-conditioning equipment also generally 
costs more to purchase than properly sized equipment. The Department 
believes that the requirement is technologically feasible and 
economically justified based on the discussion above. See the Technical 
Support Document, section 6.2, page 6.2. However, in very well 
insulated homes, equipment sizing could be such that the smallest 
available size of intended equipment might not meet the proposed sizing 
requirement. The Department would appreciate comments on what designers 
should do if unable to obtain equipment within the equipment capacity 
requirements.
    g. Section 435.503.5.7.2: Duct sealing. The proposed rule would 
contain duct sealing requirements that are more stringent than those in 
the MEC, 1992. A requirement that all low-pressure air ducts be sealed 
with mastic with fibrous backing tape was added as section 
435.503.5.7.2 of the proposed rule. This requirement is also in the 
MEC, 1995.
    Leaking supply and return ducts decrease heating and cooling 
equipment efficiency and increase energy usage while not meeting 
resident comfort requirements. Many studies of actual houses have 
revealed leaky ducts to be a major source of energy loss. One study 
showed leaks of 15 percent can reduce air conditioner efficiency by 
33--50 percent. See the Technical Support Document, section 6.4, page 
6.4. To address these problems, the proposed rule requires all low-
pressure supply and return ducts outside the conditioned space to be 
sealed with mastic with fibrous backing tape. In contrast, the MEC, 
1992 requires only that the supply ducts are sealed and allows any type 
of tape.
    Current construction practice allows the use of duct tape to 
``seal'' cracks and crevices in supply and return air ducts. Duct tape 
however, is not a sealant. A clean surface and a tight fit are required 
to produce a ``seal'' at installation and neither of these conditions 
is routinely met. If a ``seal'' is obtained at installation, however, 
the tape degrades over time as a result of deterioration of the glue. 
Properly installed duct tape ``seals'' often will leak within a year or 
two. Repairing leaking ducts after construction can be costly or 
impractical because ducts are often in inaccessible locations or they 
are wrapped with insulation that must be removed and replaced.
    Mastic is a permanent sealant. It does not degrade over time, and 
is expected to last for the life of the home. Installation is 
uncomplicated, with several methods of application from which to 
choose. Mastic has excellent adhesive and cohesive properties, even on 
typically dirty or oily surfaces found at the construction site. The 
cost of sealing ducts in existing housing is estimated to range from 
$50 to $300 when the installer has unrestricted access to the ducts 
without making it necessary to remove the finished material that may 
cover the ducts. The cost will clearly be lower during construction in 
new housing. This requirement is technologically feasible because 
mastic and tape sealing are found in current building construction 
practice. The requirement is economically justified because the cost of 
the energy saved over the 25-year analysis period would exceed the cost 
of the additional labor and materials that would be used to comply with 
this section. See the Technical Support Document, section 6.4, page 
6.4.
    h. Section 435.503.5.9.1: Backdrafting test. The Department has 
included requirements relating to the prevention of backdrafting of 
fossil-fuel-burning appliances in the proposed rule. The MEC, 1992 has 
no requirements relating to this potential health hazard. Chimney 
backdrafting in fossil-fuel-burning appliances such as oil or gas-fired 
water heaters, gas-fired clothes driers, fireplaces, or wood stoves is 
a potential threat to occupant health in residential buildings. Chimney 
backdrafting can occur when exhaust gases are drawn into a building 
through the chimney or vent because air pressure is lower inside the 
building than outside. Chimney backdrafting can cause serious health 
problems and even death can occur from exhaust gases containing or 
leading to the formation of carbon monoxide. Infants are particularly 
at risk because their respiratory systems are not fully developed, and 
they are susceptible to health effects at lower concentrations than are 
safe for most healthy adults. Sulfur dioxide and carbon dioxide also 
circulates in occupant breathing spaces as a result of backdrafting. 
These gases can cause long-term health effects such as chronic 
respiratory illness, or short-term health effects such as discomfort, 
shortness of breath, and respiratory irritation.
    The Department has determined that tests for potential backdraft 
problems should be performed in all homes with fossil-fuel-burning 
appliances that do not obtain exhaust combustion air directly from the 
outside. These tests shall be performed because the potential for 
chimney or venting failure exists in all homes and especially in all 
well sealed, poorly ventilated homes with combustion equipment. Tight 
building envelopes can cause stack-effect-induced depressurization and 
powered exhaust fans can exacerbate the problem.
    The test specified in the proposed rule is taken from the Canadian 
spillage test developed by the Canadian General Standards Board. The 
test measures the inside/outside pressure differential across a 
building shell with a micromanometer under best-case and worst-case 
scenarios. The test then compares the measurements to depressurization 
limits for combustion appliances in the house. When depressurization 
measurements exceed limits, remedial action is required before the 
house can pass the spillage test and comply with the rule. The 
Department has reviewed the Canadian spillage test and determined that 
it is technologically feasible and has included it in the proposed 
rule. See Technical Support Document, section 8.0, page 8.1.
    The cost to perform a backdrafting test is estimated to be between 
$50 and $100, depending on factors such as: the complexity of the 
house, the number of houses in a given area to be tested, and local 
weather conditions. This cost range does not include remedial measures. 
The Department has determined that there is a potential risk of 
backdrafting which justifies the inclusion of this requirement which is 
consistent with health and safety needs. See the Technical Support 
Document, section 8.0 for more information. The Department requests the 
public to comment on whether carbon monoxide alarms should be required 
in Federal residences.
    i. Section 435.504.2: Service water heating equipment. Section 
435.504.2 addresses the selection of service water heating equipment 
with the application of life-cycle cost requirements. As with space 
heating and cooling equipment, Federal agencies may either (1) select 
the most cost-effective domestic water heating equipment that minimally 
complies with Federal standards or (2) select any other equipment that 
is at least as life-cycle cost-effective. More efficient equipment may 
be selected under Subpart E. Agencies are encouraged through the 
Procurement Challenge program and other Federal initiatives to consider 
more energy-efficient equipment.
    j. Section 435.504.4: Heat traps. Heat traps are one-way valves or 
pipe configurations that prevent thermal diffusion or thermal siphoning 
of

[[Page 24172]]

potable water from the hot water heater in the house through the water 
distribution system, thus needlessly dissipating heat. Section 
435.504.4 of the proposed rule requires that water heaters with 
vertical pipe risers have heat traps. This requirement is not in the 
MEC, 1992 and was taken from the codified version of Standard 90.2-
1993. Heat traps are also technologically feasible because they are 
part of current water heater manufacturing practice. The use of heat 
traps is a low-cost method of reducing water heating energy use already 
installed on many commercially available water heaters. Therefore, heat 
traps are economically justified because the net annual savings over 
the lifetime of the water heater exceeds the initial first cost of the 
additional hardware. See the Technical Support Document, section 6.5, 
page 6.5.
2. Miscellaneous Revisions That Are Contained in Subpart E of the 
Proposed Rule, Not in the MEC, 1992
    The proposed rule includes the following additional requirements 
that are not part of the MEC, 1992. Section 435.502.1.4 contains a 
clarification to the MEC, 1992 in that access openings, which are 
considered part of the thermal envelope element, must be evaluated as 
part of the overall building thermal envelope element (e.g., floors, 
walls, roof/ceiling, etc.,). The Department believes this is 
technologically feasible because access openings are commonly insulated 
in colder climates and are economically justified because it imposes no 
additional cost to the building. See the Technical Support Document, 
section 6.9, page 6.10.
    Section 435.502.1.5 contains a requirement for the insulation of 
foundations supporting masonry veneer. The Department has determined 
that the requirement is technologically feasible because it reflects 
current building construction practice. Although some energy would be 
lost, the energy loss would be small and economically justified when 
weighed against the costs that would be incurred by damage to the 
masonry veneer. Damage can occur due to settling of the masonry as the 
insulation is compressed. The technical justification for this 
requirement may be found in the Technical Support Document, section 
6.10, page 6.10.
    Section 435.502.2.1.3 contains an equation to calculate the total 
floor heat loss of the proposed building. The equation requires that 
all floors of different construction (in aggregate) must meet the 
U0 requirements for floors over unheated spaces. The 
Department has determined that the requirement is technologically 
feasible. The technical justification for this requirement may be found 
in the Technical Support Document, section 6.11, page 6.10. The 
equation is economically justified because the use of the equation to 
determine the U-value requirement for floors over unheated spaces is 
cost-effective. Variations in floor configurations are not required by 
this proposed rule.
    Section 435.502.2.1.4 contains a clarification of acceptable slab 
insulation placement which reflects current building construction 
practice. The Department has determined that the requirement is 
technologically feasible because it reflects current standard building 
construction practice. The technical justification for this requirement 
may be found in the Technical Support Document, section 6.11, page 
6.11. The clarification is economically justified because it imposes no 
additional slab insulation requirements. There is a potential for 
installation cost savings due to the flexibility offered by the 
proposed requirement.
    Section 435.502.3.2 simplifies language on caulking and sealing 
requirements for typical air sealing measures. The Department has 
determined that the requirement is technologically feasible because the 
simplified language generally reflects the requirements contained in 
the MEC, 1992. The technical justification for this requirement may be 
found in the Technical Support Document, section 6.13, page 6.12. The 
simplified language is economically justified because it imposes no 
additional costs to the construction of the building.
    Section 435.502.3.1 refers to updated reference standards for 
allowable infiltration rates for windows and doors. This section 
reflects current manufacturing standards for air-tightness of pre-
fabricated windows and doors. The Department has determined that the 
requirement is technologically feasible because current manufactured 
windows and doors are built to the updated referenced standards. The 
updated reference standards are economically justified because the 
proposed rule imposes no additional cost or requirements on 
manufacturing quality or performance. The technical justification for 
this requirement may be found in the Technical Support Document, 
section 6.15, page 6.14.

F. Subpart F: [ Reserved ]

    Subpart F is reserved for a simplified compliance approach the 
Department is developing. This approach will make it easier to 
determine compliance with this rule. This revised simplified compliance 
approach would be different from that contained in the MEC, 1992, 1993, 
and 1995. This approach is expected to be similar to the Department's 
``MECcheck'' tables which display pre-calculated configurations in 
compliance with the MEC, 1992, 1993 or 1995. The Department is planning 
to produce a ``Federal'' version of MECcheck.

G. Subpart G: Radon Control

    Subpart G provides the minimum requirements for the control of 
radon from the ground and from construction materials associated with 
Federal residential buildings. The application of requirements for 
radon control apply in addition to the provisions of Subpart D or E.
    The ECPA, as amended, directs that the Federal residential building 
energy standard ``consider, in consultation with the Environmental 
Protection Agency and other Federal agencies, and where appropriate 
contain, measures with regard to radon and other indoor air 
pollutants.'' 42 U.S.C. 6834(a)(2)(C). The intent is for the Department 
to address health concerns related to air quality in Federal buildings.
    The Department has determined that radon is a potential health 
hazard in residential buildings and that the proposed rule should 
address radon testing and mitigation requirements. Radon is a gas that 
exists naturally in many soils and enters a building through the 
foundation. Radon concentrations in soil vary widely across the United 
States and even within a small region, such as a county. If high 
concentrations of radon are present in the soil below a building, then 
measures to control radon are needed. Approximately 6 percent of 
existing single-family homes in the United States or 5.8 million homes 
in 1990 have average radon levels greater than 4 pCi/L per year, the 
threshold level determined by the EPA to require corrective action. 
Approximately 0.7 percent of existing single-family homes in the 
country have average radon levels greater than 10 pCi/L per year. The 
EPA estimates that indoor radon causes between 7,000 and 30,000 lung 
cancer deaths per year. This range is based on the uncertainty inherent 
in the many factors contributing to the risk of radon exposure and on a 
national residential radon survey estimate of an average level of 1.25 
pCi/L per year. The EPA's best estimate is that 14,000 lung cancer 
deaths per year result from residential radon exposure.

[[Page 24173]]

    In this proposed rule the Department would be accepting EPA's 
determination that radon-resistance control measures should only be 
required in zones (counties) of high radon potential. Such zones are 
defined by the EPA ``U.S. Map of Radon Zones'' or local data if 
available. The proposed rule specifies the EPA ``U.S. Map of Radon 
Zones'' as the default source designating counties where the proposed 
requirements apply. Table 702.2 in the Appendix of the proposed rule 
lists the applicable counties. The EPA ``U.S. Map of Radon Zones'' is 
not always sufficient to predict radon concentrations accurately. There 
may be instances where specific locations will be assigned to an 
inappropriate radon potential zone in the EPA ``U.S. Map of Radon 
Zones''. To accommodate for such inaccuracies, the proposed rule allows 
considering appropriate evidence and ``overruling'' the EPA ``U.S. Map 
of Radon Zones.''
    Consideration of non-EPA data is justifiable given that studies on 
radon concentrations in many Federal installations are already 
available or are underway.
    The proposed rule uses the following approach for addressing radon 
when radon-resistant construction is necessary:
    (1) Foundation sealing with passive (non-mechanical) venting of 
soil gas to the outside;
    (2) Long-term and short-term post-occupancy radon testing to verify 
occupant safety;
    (3) Mitigation, if the tests reveal high radon concentrations; and
    (4) Post-mitigation testing for radon and potential backdrafting to 
ensure safety.
    Each of these four approaches is described in further detail below. 
The proposed radon requirements are technologically feasible because 
the techniques used are part of current standard building construction 
practice in many areas of the U.S. and are consistent with the EPA 
Model Standards and Techniques for Control of Radon in New Residential 
Buildings (EPA 402-R-94-009, March 1994). The Department is accepting 
EPA's analysis of the costs and benefits of radon control. See RS-34, 
pages ES-1-ES-4. The Technical Support Document (Chapter 7.0) provides 
construction specifications and technical justifications for the 
proposed rule. The proper initial abatement approach in areas of 
potentially high radon concentrations is to seal potential sources of 
air leakage in the foundation and vent the soil gas below the 
foundation. Such venting uses a pipe that extends from the foundation, 
through the house, and out the roof. This approach is consistent with 
the approach in the EPA Radon Mitigation Standards (EPA 402-R-93-078, 
October 1993). It cannot be conclusively determined before construction 
that a radon source exists that is strong enough to raise indoor 
concentrations above the EPA action level. Therefore, it would be 
fiscally imprudent initially to require measures beyond foundation 
sealing and the ``passive'' vent pipe. If elevated radon levels are 
found after construction and these initial measures were not installed, 
the cost of the retrofit would be much higher than the cost during 
initial construction.
    The radon concentration within a residence can only be determined 
after the residence is built and occupied. This is due to the 
interaction of radon sources with construction characteristics of the 
house and the indoor pressure-driven air flow that is influenced by 
heating, ventilating and air-conditioning equipment under occupant 
control. Because short-term tests are not adequate to obtain annual 
average radon concentrations, the proposed rule requires long-term 
post-occupancy testing of residences built in specified locations. The 
long-term test requires between 6 months and 1 year and is the most 
accurate measure of chronic radon levels an occupant will encounter. A 
short-term test which lasts between seven and 60 days, is also proposed 
to ensure that occupants are not exposed to radon levels in excess of 
20 pCi/L while the long-term test is in progress. Testing procedures 
and devices must conform to the EPA Protocols for Radon and Radon Decay 
Measurements in Homes (EPA 402-R-93-003, June 1993).
    Testing may show that sealing the foundation and installing the 
passive vent are not sufficient to control the radon level. In such 
cases, the proposed rule requires that a fan be installed and operated 
in the foundation vent system to lower radon concentrations. Vent fans 
must be activated when the long-term test reveals radon concentrations 
greater than the EPA action level of 4 pCi/L or if the first short-term 
test and a second short-term confirmatory test reveals radon levels in 
excess of 20 pCi/L. The EPA Radon Mitigation Standards offer guidance 
on installing the fan.
    Follow-up tests are required to ensure that the vent fan is 
successful at lowering indoor radon levels. Additionally, because the 
foundation vent fan may under certain circumstances cause fossil-fuel-
burning appliances to tend to backdraft, both the proposed rule and the 
EPA Radon Mitigation Standards require testing for backdrafting of 
chimney and combustion vents. Section 435.503.5.9.1 of the proposed 
rule, referenced in Subpart G, specifies the test procedure to be used 
to check for potential backdrafting.
    The Department departs from the EPA ``Radon Mitigation Standards'' 
in several respects. First, the proposed rule allows data on radon 
concentrations at Federal facilities to take precedence over the EPA 
``U.S. Map of Radon Zones'' for determining whether radon-resistant 
construction is required. Second, if the housing is located in a high 
radon zone, the proposed rule requires testing and, if necessary, 
mitigation and further post mitigation testing. Third, many sections of 
the EPA Radon Mitigation Standards that are unenforceable, including 
discussions, explanations, or recommendations, have been deleted. 
Fourth, the Department provides more detail in some construction 
specifications so that the required measures can be more easily 
verified. Fifth, the Department did not explicitly include the EPA 
requirements for sealing the above-grade structure to help limit air 
infiltration through the foundation. This was because similar 
requirements are already included in section 435.502.3 of the proposed 
rule.
    The Department has thus followed the general approach outlined in 
the EPA Radon Mitigation Standards. Radon-resistant construction is 
only required in locations with high radon potential and a phased 
approach to control is specified. Control should be based on a sealed 
foundation, passive venting of soil gas and radon testing after 
occupancy. Only if necessary should a fan be added to the vent system. 
The Department consulted and provided to the EPA draft copies of the 
proposed rule (including radon requirements) and the Environmental 
Assessment supporting the proposed rule. The EPA has provided extensive 
comments on the requirements for radon in the proposed rule and the 
Department has incorporated many of those comments in Subpart G.

H. Subpart H: Standards

    This section provides a list of all the standards referenced in the 
proposed rule. This section has been updated from the MEC, 1992 because 
some requirements contained in this proposed rule are not contained in 
the MEC, 1992 reference standards. Also, some referenced standards have 
been updated to newer versions since 1992.

[[Page 24174]]

IV. Consultation

    In developing today's proposal, the Department has consulted with 
outside parties, including state and local code officials, private 
sector representatives, and other Federal agencies, as required by 
section 305(a)(1) of ECPA.
    In addition, the Department continues to work with the relevant 
private sector organizations and the states to analyze potential 
improvements to the MEC and to facilitate the adoption of such 
improvements in both the public and private sectors. Adoption of the 
MEC format in today's proposal provides a ready basis for the 
incorporation of future code improvements as they are developed and 
approved through the standard process for model code change proposals.
    Finally, the Department will specifically provide Federal agencies 
with information regarding the availability of energy-efficiency 
equipment and emerging developments that improve building envelopes. 
This support will help keep Federal agencies current regarding energy-
efficiency opportunities between the updates of this rule.

V. Energy and Economic Impacts

    Section 305(a)(2)(A) of ECPA requires that the proposed rule meet 
or exceed the MEC, 1992. The proposed rule is based on the MEC, 1992, 
with the additions described in Section III above. Overall, the 
proposed rule, if adopted would reduce energy use by approximately 11 
percent for single-family residences and 26 percent for multi-family 
residences, as compared to the MEC, 1992.
    The energy estimates reported here are based on the minimum 
specifications required in Subpart E of the proposed rule. Additional 
cost-effective energy-efficiency improvements in new Federal 
residential buildings are facilitated by this rule through Subpart D, 
which provides a means of documenting the energy savings and cost-
effectiveness of more energy-efficient building designs.
    The Department has prepared a Technical Support Document that 
includes an economic analysis. It concludes that there are no 
significant adverse economic effects from adopting the proposed rule. 
The proposed rule, when compared to the MEC, 1992, will result in a 
positive net flow of benefits from energy savings that more than 
offsets higher capital construction and other costs at estimated 
Federal costs of energy.
    The national net effect of the proposed rule is a cumulative 
savings of $870,000 for the approximately 3,000 Federal housing units 
constructed each year. These net effects are based on the net present 
value of energy savings and capital costs over a 25-year period. See 
the Economic Analysis at page 6.

VI. Technological Feasibility and Economic Justification

    The standards proposed today are technologically feasible and 
economically justified to the Federal government as required by Section 
305(a)(1) of ECPA.
    The Department used the life-cycle cost methodology reflected in 
the microcomputer program entitled ``ARES'' for evaluating the life-
cycle cost-effectiveness of various thermal envelope EEMs. Only those 
EEMs the Department judged technologically feasible were reviewed.
    The life-cycle cost analysis compares the cost and benefits of all 
the EEMs. The HVAC equipment performance efficiencies are specified at 
current minimum EPCA levels. See 10 CFR Part 430. These are the same 
levels found in the MEC, 1993. Given a set of fuel prices, financial 
and economic parameters, and EEM costs for a specific location, ARES 
identifies the life-cycle cost resulting from any given set of EEMs. 
Energy costs and discount rates reflect estimated Federal costs of 
energy and the Federal discount rate established annually by the 
Federal Energy Management Program for the life-cycle cost analysis 
required by 10 CFR Part 436. The present value of the total costs for 
several EEMs are compared, and the results are used to set the code to 
energy-efficiency measure levels that achieve the lowest energy-related 
total cost for construction, operation and maintenance for each 
location studied. The resulting thermal-envelope-component values are 
presented as a function of heating degree-days.
    The technical feasibility of the EEMs contained in the ARES energy 
data base was assessed by determining that they were technologically 
verifiable, commercially available, and in common construction 
practice. Construction features that cannot be analyzed by ARES because 
the technical or economic data has not been well established, or 
features that have small additional costs but significant potential for 
energy savings, have been analyzed by practicable architectural, 
engineering, or economic judgment.

VII. Measures Concerning Radon and Other Indoor Air Pollutants

    Section 305(a)(2)(C) of the ECPA requires the Department to 
consider, where appropriate, measures with regard to radon and other 
indoor air pollutants. The Department has proposed a set of radon 
requirements concerning the control and mitigation of radon in Federal 
residences. These requirements draw heavily from the EPA Radon 
Mitigation Standards, EPA 402-R-93-078, April 1994. As part of these 
proposed requirements, post-occupancy testing is proposed for locations 
with high radon potential to discover whether radon concentrations 
within the residences are acceptable. The proposed Federal rule also 
includes requirements for addressing the potential for backdrafting of 
combustion by-products, such as carbon monoxide, from fossil-fuel-
burning appliances.

VIII. Findings and Certification

A. Review Under the National Environmental Policy Act

    The Department has completed an Environmental Assessment (EA), see 
Environmental Assessment of the Impacts on Building Habitability and 
the Outdoor Environment Resulting from the Proposed Federal Residential 
Code, in support of the proposed rule, pursuant to the implementing 
regulations of the Council on Environmental Quality (CEQ) (40 CFR Parts 
1500-1508), the ``National Environmental Policy Act of 1969, as 
amended,'' (NEPA) (40 U.S.C. 4221 et seq.), the Department's NEPA 
Implementing Procedures, (10 CFR Part 1021), and the Secretarial Policy 
on the National Environmental Policy Act (June 1994). Section V.B.2. of 
the Secretarial Policy requires, wherever possible, that the Department 
provide an opportunity for interested parties to review environmental 
assessments prior to the Department's formal approval of such 
assessments. The written public comment procedures for this EA are 
discussed below in section IX.
    The draft EA addresses the possible incremental environmental and 
indoor habitability effects attributable to the application of the 
proposed rule. The analysis in the draft EA demonstrates that the 
potential environmental effects from the proposed rule would be 
limited. The only impacts would be a decrease in outdoor air pollutants 
resulting from decreased fossil fuel burning and temporary increases in 
formaldehyde concentrations in the Federal residences.

B. Environmental Protection Agency Review

    As required by the Federal Energy Administration Act of 1974, 15 
U.S.C. 766(a)(1), a copy of this proposed rule

[[Page 24175]]

was submitted to the Administrator of the Environmental Protection 
Agency for comments on the impact of the proposed rule on the quality 
of the environment.

C. Regulatory Planning and Review

    This regulatory action has been determined to be a significant 
regulatory action under Executive Order No. 12866, 58 FR 51735 (October 
4, 1993), but not economically significant. Accordingly, today's action 
was subject to review under the Executive Order by the Office of 
Information and Regulatory Affairs (OIRA) and OIRA has completed its 
review.

D. Federalism Review

    Executive Order 12612, 52 FR 41685 (October 30, 1987), requires 
that regulations, rules, legislation, and any other policy actions be 
reviewed for any substantial direct effects on states, on the 
relationship between the Federal government and the states, or in the 
distribution of power and responsibilities among various levels of 
government. If there are substantial effects, then the Executive Order 
requires preparation of a federalism assessment to be used in all 
decisions involved in promulgating and implementing a policy action.
    The proposed rule would establish energy-efficiency requirements 
solely applicable to new Federal residential buildings. It does not 
impose any requirements on state governments. Therefore, the Department 
finds that today's proposed rule, if finalized, will not have a 
substantial direct effect on state governments, therefore, a federalism 
assessment has not been prepared.

E. Review Under the Executive Order on Metric Usage in Federal 
Government Programs

    Section 5164(b) of the Omnibus Trade and Competitiveness Act of 
1988, 15 U.S.C. 205b, which amended the Metric Conversion Act of 1975, 
designates the metric system of measurement as the preferred system of 
weights and measures for trade and commerce. This law requires Federal 
agencies by the end of fiscal year 1992 and to the extent economically 
feasible, to use the metric system in U. S. procurements, grants, and 
other business-related activities, except to the extent that such use 
is impractical or likely to cause significant inefficiences or loss of 
markets to U.S. firms. The Omnibus Trade and Competitiveness Act of 
1988 also requires Federal agencies to establish guidelines and to 
report as part of its annual budget submission on the actions it plans 
in order to implement fully the metric system of measurement. This 
policy is also stated and amplified by Executive Order 12770 of July 
25, 1991, ``Metric Usage in Federal Government Programs.''
    This rule is the first use of a dual metric/English (soft metric 
conversion) system of measurement in a Federal building energy 
regulation. The metric system of measurement is followed by the English 
system in parentheses. In using this dual system, the Department is 
facilitating the goal of 15 U.S.C. 205b to promote competitiveness by 
relating Federal energy standards to the international measurements 
that United States companies must use to meet world demand for building 
components. The rule retains reference to English system measurements 
for those companies that do not have the ability to readily translate 
between metric and English units. The use of this dual system of 
measurement does not change the requirements of the proposed rule and 
has no substantive impact on the users of the proposed rule.

F. Review Under Executive Order on Civil Justice Reform

    Section 3 of Executive Order 12988, 61 FR 4729 (February 7, 1996), 
instructs each agency to adhere to certain requirements in promulgating 
new regulations. These requirements, set forth in Section 3(a) and (b), 
include eliminating drafting errors and needless ambiguity, drafting 
the regulations to minimize litigation, providing clear and certain 
legal standards for affected legal conduct, and promoting 
simplification and burden reduction. Agencies are also instructed to 
make every reasonable effort to ensure that the regulation describes 
any administrative proceeding to be available prior to the judicial 
review and any provisions for the exhaustion of administrative 
remedies. The Department has determined that today's regulatory action 
meets the requirements of section 3(a) and (b) of Executive Order 
12988.

G. Review Under the Regulatory Flexibility Act

    The Regulatory Flexibility Act of 1980, 5 U.S.C. 601-612, requires 
that an agency prepare an initial regulatory flexibility analysis and 
that it be published at the time of publication of general notice of 
proposed rulemaking for the rule. This requirement does not apply if 
the agency ``certifies that the rule will not, if promulgated, have a 
significant economic impact on a substantial number of small 
entities.'' 5 U.S.C. 605.
    The proposed rule only imposes requirements on the Federal 
government for the construction of new Federal residential buildings. 
Therefore, the Department certifies that this rule, if promulgated, 
would not have a significant economic impact on a substantial number of 
small entities.

H. Paperwork Reduction Act Review

    This proposed rule was examined with respect to the Paperwork 
Reduction Act, 44 U.S.C. 3501 et seq., which directs agencies to 
minimize Federal information collection and reporting burdens imposed 
on individuals, small businesses, and state and local governments.
    This proposed rule would establish requirements for the design of 
new Federal residential buildings. It does not impose requirements for 
the collection or reporting of information to the Federal Government. 
Accordingly, clearance under the Paperwork Reduction Act of 1980 is not 
required by the Office of Information and Regulatory Affairs of the 
Office of Management and Budget.

I. Review Under Section 32 of the Federal Energy Administration 
Authorization Act

    Pursuant to Section 301 of the Department of Energy Organization 
Act (Pub. L. 95-91), the Department is required to comply with Section 
32 of the Federal Energy Administration Authorization Act of 1974, as 
amended by section 9 of the Federal Energy Administration Authorization 
Act of 1977. The findings required of the Department by Section 32 
serve to notify the public regarding the use of commercial standards in 
a proposal and through the rulemaking process. It allows interested 
persons to make known their views regarding the appropriateness of the 
use of any particular commercial standard in a notice of proposed 
rulemaking. Section 32 also requires that the Department consult with 
the Attorney General and the Chairman of the Federal Trade Commission 
concerning the impacts of such standards on competition.
    Today's proposed rule adopts, in significant part, the MEC, 1992, 
1993 and 1995 and the relevant reference standards (RS) contained in 
the MEC, 1992, 1993, and 1995. The reference standards can be found in 
Subpart H of the proposed rule designated as RS-1--RS-34. In addition, 
the proposed rule adopts certain requirements from Standard 90.2-1993.
    The Department has evaluated the promulgation of the above 
standards with regard to compliance with Section

[[Page 24176]]

32(b). The Department is unable to conclude whether these standards 
fully comply with the requirements of Section 32(b), i.e., that they 
were developed in a manner which fully provided for public 
participation, comment, and review. Therefore, the Department now 
invites public comment on the appropriateness of incorporating these 
industry standards in its final rule. As required by Section 32(c), the 
Department will consult with the Attorney General and the Chairman of 
the Federal Trade Commission concerning the impact of these standards 
on competition, prior to issuing a notice of Final rulemaking.

J. Unfunded Mandates Reform Act Review

    Title II of the Unfunded Mandates Reform Act of 1995 (the Act), 
enacted as Pub. L. 104-4 on March 22, 1995, requires each Federal 
agency, to the extent permitted by law, to prepare a written assessment 
of the effects of any Federal mandate in a proposed or final agency 
rule 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 (adjusted annually for inflation) in any one year. The 
requirements do not apply if the rule incorporates regulatory 
requirements that are specifically set forth in law. 2 U.S.C. 1531, 
1532.
    Furthermore, section 204(a) of the Act, 2 U.S.C. 1534(a), requires 
the Federal agency to develop an effective process to permit timely 
input by elected officers (or their designees) of state, local, and 
tribal governments on a proposed ``significant intergovernmental 
mandate.'' A ``significant intergovernmental mandate'' under the Act is 
any provision in a Federal agency regulation that: (1) would impose an 
enforceable duty upon state, local, or tribal governments (except as a 
condition of Federal assistance); and (2) may result in the expenditure 
by state, local, and tribal governments, in the aggregate, of $100 
million (adjusted annually for inflation) in any one year. Section 203 
of the Act, which supplements section 204(a), provides that before 
establishing any regulatory requirements that might significantly or 
uniquely affect small governments, the agency shall have developed a 
plan that, among other things, provides for notice to potentially 
affected small governments, if any, and for a meaningful and timely 
opportunity to provide input in the development of regulatory 
proposals. 2 U.S.C. 1533.
    The rule proposed today would establish building energy-efficiency 
standards for new Federal residential buildings pursuant to section 
305(a) of the Energy Conservation and Production Act, as amended. 42 
U.S.C. 6834(a). It does not include any Federal requirements that would 
result in the expenditure of money by state, local, and tribal 
governments. Therefore, the requirements of the Unfunded Mandates 
Reform Act of 1995 do not apply to this rulemaking.

IX. Public Comment Procedures

A. Participation in Rulemaking

    The Department encourages the maximum level of public participation 
in this rulemaking. Representatives of Federal agencies, utilities, 
state and local governments, building code organizations, and builder 
associations, building owner associations, as well as individuals, 
architects, engineers, builders, building owners, consumers, and others 
are urged to submit written statements on the proposed rule. The 
Department also encourages interested persons to participate in the 
public hearing to be held in Washington, D.C., at the time and place 
indicated in this Notice.
    The Department of Energy has established a comment period of 90 
days following publication for interested persons to comment on this 
proposed rule. All comments will be available for review in the 
Department's Freedom of Information Reading Room.

B. Solicitation of Public Comments

    The Department welcomes comments on any aspects of the proposed 
rule and supporting documentation, including the draft EA. In 
particular, the Department is seeking comments on those specific issues 
described below. The Department requests that comments of a technical 
nature be supported by substantive data.
    In particular, the Department requests comments addressing the 
quantitative and methodological basis for setting specific ventilation 
requirements in energy codes that relate to Federal residential 
construction. Ventilation can help mitigate indoor air pollutants and 
moisture problems in many situations. Excessive ventilation, however, 
can increase energy use but not necessarily mitigate the health effects 
of some indoor air pollutants. The Department is interested in comments 
on how best to set ventilation requirements to achieve adequate indoor 
air quality without incurring unnecessary construction or energy costs.
    Second, the Department seeks comments on whether all residences 
with fuel-burning devices requiring a vent pipe or chimney should be 
required to undergo testing for depressurization-induced chimney 
failure (backdrafting). The Department has included this requirement in 
the proposed rule because of the health hazard of backdrafting.
    Third, the Department specifically requests comments regarding the 
treatment of equipment efficiency for space heating and cooling and 
water heating. The proposed rule incorporates the existing Federal 
minimum appliance standards, while relying on other Federal initiatives 
to encourage the identification and use of more efficient equipment 
where economically justified.
    The Department would have to establish the economic benefits and 
technological feasibility of any equipment efficiency specifications 
that would be included in this rule that exceed the Federal minimum 
requirements.
    Fourth, the Department requests comments concerning the 
technological feasibility and economic justification relative to the 
heating and cooling equipment sizing provisions contained in the 
proposed rule.
    Fifth, the Department requests comments concerning suggestions on 
approaches for crediting measures that use renewable sources of energy.
    Sixth, the Department requests comments on the appropriateness of 
the approach identified in section 435.402.1.6 of the proposed rule for 
dealing with equipment efficiencies under the whole building energy 
analysis compliance path in Subpart D.
    Seventh, the Department requests comments on whether carbon dioxide 
alarms should be required in Federal residences.
    Eighth, the Department requests comment on how this proposed rule 
could address equipment technologies for which a means of evaluating 
and comparing energy performance has not yet been fully developed.
    Finally, as previously stated, the Department of Energy requests 
public review and comments on the draft EA.

C. Written Comment Procedures

    Interested persons are invited to participate in this proceeding by 
submitting written data, views, or comments with respect to the 
proposed rulemaking.
    Written comments (ten copies) shall be submitted to the address 
indicated in the ADDRESSES section of this notice. The copies must be 
received by the date indicated in the DATES section of this notice. 
Comments should be identified on both the outside of the envelope and 
on the documents themselves with the

[[Page 24177]]

designation, Energy Efficiency Code for New Federal Residential 
Buildings (Docket No. EE-RM-96-300). In the event any person wishing to 
provide written comments cannot provide ten copies, alternative 
arrangements can be made in advance with the Department.
    All comments received on or before the date specified at the 
beginning of this proposed rule and other relevant information will be 
considered by the Department before final action is taken on the 
proposed rule. All written comments will be available for examination 
in the Rule Docket File in the Department's Freedom of Information 
Office Reading Room at the address provided at the beginning of this 
document before and after the closing date for comments. In addition, a 
transcript of the proceedings of the public hearings will be filed in 
the docket.
    Pursuant to the provisions of 10 CFR 1004.11, any person submitting 
information that is believed to be confidential, and which may be 
exempt by law from public disclosure, should submit one complete copy, 
and two copies from which the information believed to be confidential 
has been deleted. The Department will make its own determination of any 
such claim and treat it according to its determination.

D. Public Hearings

1. Procedure for Submitting Requests To Speak
    To have the benefit of a broad range of public viewpoints in this 
rulemaking, the Department will hold a public hearing at the time and 
place indicated in the DATES and ADDRESSES sections of this notice. Any 
person who has an interest or who is a representative of a group or 
class of persons that has an interest in the proposed rule or the 
associated environmental assessment may request an opportunity to make 
an oral presentation. A request to speak at the public hearing must be 
mailed to the address or telephoned to the number indicated in the 
ADDRESSES section of this notice and received by the time specified in 
the DATES section of this notice.
    The person making the request should briefly describe his or her 
interest in the proceedings and, if appropriate, state why that person 
is a proper representative of the group or class of persons that has 
such an interest. The person should also provide a telephone number 
where he or she may be contacted during the day. Each person selected 
to be heard will be notified by the Department as to the approximate 
time he or she will be speaking. Ten copies of the speaker's statement 
must be submitted at or before the hearing. In the event any person 
wishing to testify cannot meet this requirement, alternative 
arrangements can be made in advance with the Department.
2. Conduct of Hearings
    The Department reserves the right to schedule persons to be heard 
at the hearing, to schedule their representative presentations, and to 
establish procedures governing the conduct of the hearing. The length 
of each presentation is limited to 15 minutes or otherwise based on the 
number of persons requesting an opportunity to speak.
    A Department official will preside at the hearing. This will not be 
a judicial or evidentiary-type hearing. It will be conducted in 
accordance with 5 U.S.C. 553 and Section 501 of the Department of 
Energy Organization Act, 42 U.S.C. 7191. At the conclusion of all 
initial oral statements, each person who has made an oral statement 
will be given the opportunity to make a rebuttal or clarifying 
statement. The statements will be given in the order in which the 
initial statements were made and will be subject to time limitations.
    Questions may be asked only by those conducting the hearing. Any 
interested person may submit to the presiding official written 
questions to be asked of any person making a statement at the hearing. 
The presiding official will determine whether the question is relevant 
or whether time limitations permit it to be presented for a response.
    Any further procedural rules needed for the proper conduct of the 
hearing will be announced by the presiding official at the hearing.
    A transcript of the hearing will be prepared by the Department and 
made available as part of the administrative record for this 
rulemaking. It will be on file for inspection at the Department's 
Freedom of Information Reading Room as provided at the address 
indicated at the beginning of this document.
    If the Department must cancel the public hearing, the Department 
will make every effort to publish an advance notice of such 
cancellation in the Federal Register. The hearing date may be canceled, 
for example, in the event no member of the public requests the 
opportunity to make an oral presentation.

List of Subjects in 10 CFR Part 435

    Buildings, Energy conservation, Energy efficiency, Engineers, 
Federal buildings and facilities, Housing.

    Issued in Washington, DC, on April 1, 1997.
Brian T. Castelli,
Chief of Staff, Energy Efficiency and Renewable Energy.

    For the reasons set forth in the preamble, Part 435 of Chapter II 
of Title 10 of the Code of Federal Regulations is proposed to be 
revised as set forth below:

PART 435--ENERGY EFFICIENCY CODE FOR NEW FEDERAL RESIDENTIAL 
BUILDINGS

435.100  Explanation of numbering system for this part.

Subpart A--Administration and Enforcement

435.101  Scope and general requirements.
435.102  Materials and equipment.
435.103  Alternate materials'method of construction, design, or 
insulation systems.
435.104  [Reserved].
435.105  [Reserved].
435.106  [Reserved].
435.107  Precedence.
435.108  Life-cycle cost analysis.

Subpart B--Definitions

435.201  Definitions.

Subpart C--Design Conditions

435.301  Scope.
435.302  Thermal design parameters.
435.303  Mechanical ventilation criteria.

Subpart D--Design by Systems Analysis; Design Utilizing Renewable 
Energy Sources

435.401  Scope.
435.402  Systems analysis.
435.403  Renewable energy source analysis.

Subpart E--Design by Component Performance Approach

435.501  Scope.
435.502  Building thermal envelope requirements.
435.503  Building mechanical systems and equipment.
435.504  Service water heating.
435.505  Electrical power and lighting.

Subpart F--[Reserved]

Subpart G--Radon Control

435.701  General.
435.702  Scope.
435.703  Compliance.
435.704  Alternative systems.
435.705  Conflict with other standards, codes, or regulations.
435.706  Qualification of testers and installers.
435.707  Design and construction requirements.

Subpart H--Standards

435.801  Reference standards.
435.802  Abbreviations and acronyms used in reference standards.

[[Page 24178]]

Appendix to Part 435  Figures and Tables

    Authority: 42 U.S.C. 6831-6832, 6834-6836; 42 U.S.C. 8253-54; 42 
U.S.C. 7101, et seq.


Sec. 435.100  Explanation of numbering system for this part.

    100.1  General. For the purposes of this part, a derivative of two 
different numbering systems will be used.
    100.1.1  For the purpose of designating a section, the numbering 
system employed in the Code of Federal Regulations (CFR) will be 
employed. The number ``435'' which signifies part 435, Chapter II of 
Title 10, Code of Federal Regulations, is used as a prefix for all 
section headings. The suffix is a three digit number. For example, the 
life-cycle cost analysis section of this part is designated 
Sec. 435.108.
    100.1.2  Within each section, a numbering system common to many 
national voluntary consensus model codes is used. A decimal system is 
used to denote paragraphs and subparagraphs within a section. For 
example, 435.502.1.2 refers to subparagraph 2 of paragraph 1 of 
Sec. 435.502.
    100.2  The hybrid numbering system is used for two purposes:
    100.2.1  The use of the Code of Federal Regulation numbering system 
allows the researcher using the CFR easy access to this part.
    100.2.2  The use of the second system allows the builder, designer, 
architect or engineer easy access to the technical provisions because 
they are familiar with the numbering system and its format generally 
conforms to existing building codes. This system was chosen because of 
its commonality among the buildings industry.

Subpart A--Administration and Enforcement


Sec. 435.101  Scope and general requirements.

    101.1  Title. This part shall be known as the Energy Efficiency 
Code for New Federal Residential Buildings and is referred to herein as 
``this part.''
    101.2  Purpose. The provisions of this part provide minimum 
standards for energy efficiency for the design of new Federal 
residential buildings. The performance standards are designed to 
achieve the maximum practicable cost-effective improvements in energy 
efficiency and increases in the use of non-depletable sources of 
energy. It is intended that these provisions provide flexibility to 
permit the use of innovative approaches and techniques to achieve 
efficient utilization of energy. This part also establishes minimum 
requirements for the control of radon in new Federal residential 
buildings.
    101.3  Compliance. This part requires:
    101.3.1  Use of a systems approach for the entire building and its 
energy-using subsystems which may utilize renewable sources as 
established in Subpart D or use of a component performance approach for 
various building elements and mechanical systems and components as 
established in subpart E; and
    101.3.2  Compliance with the radon requirements is established in 
subpart G.
    101.4  Scope. This part provides design requirements for building 
envelopes for adequate thermal resistance and low air leakage and the 
design and selection of mechanical, electrical, service water-heating 
and illumination systems and equipment which will enable efficient use 
of energy in new Federal residential building construction. It applies 
to the design and construction of all new Federal residential buildings 
that are three stories or less above grade that are not subject to 
state or local building codes. Federal residential buildings more than 
three stories above grade and all Federal nonresidential buildings must 
comply with the Energy Code for Federal Commercial and Multi-Family 
High-Rise Residential Buildings.
    101.4.1  Radon control. This part also establishes requirements for 
control of radon for certain new Federal residential buildings. The 
applicability of those requirements is established in section 702.
    101.4.2  Building types.
    101.4.2.1  Group R Federal residential buildings. For the purposes 
of this part, Group R residential buildings include:
    (a) Type A-1--Detached one and two family dwellings, and
    (b) Type A-2--Other residential buildings, three stories or less in 
height.
    101.4.2.2  Other buildings. Any buildings and structures not 
included in section 101.4.2.1 are not covered by this rule.
    101.4.3  Exempt buildings. The building types that are exempt are 
as follows: assembly, health, and
    101.4.3.1  Buildings and structures or portions thereof whose peak 
design rate of energy usage is less than 1.0 W (3.4 Btu/h) or 10.8 W/
m\2\ (1 W/ft\2\) of floor area for all purposes.
    101.4.3.2  Buildings and structures or portions thereof which are 
neither heated nor cooled.
    101.4.4  Application to existing buildings.
    101.4.4.1  Additions to existing buildings. Additions to existing 
buildings or structures may be made to such buildings or structures 
without making the entire building or structure comply. The new 
addition shall conform to the provisions of this part as they relate to 
new construction only.


Sec. 435.102  Materials and equipment.

    102.1  Identification.
    102.1.1  General. Materials and equipment shall be identified on 
the building plans and specifications in a manner that will allow for a 
determination of their compliance with the applicable provisions of 
this part.
    102.1.2  Building envelope insulation. Building envelope insulation 
shall have a thermal resistance (R) identification marker on each piece 
of building envelope insulation 0.3048 m (12 in.) or greater in width. 
Alternatively, a signed and dated certification for the insulation 
installed in each element of the building envelope shall be provided, 
listing the type of insulation, the manufacturer, and the R-value. For 
blown-in or sprayed insulation, a certification shall be provided that 
identifies the initial installed thickness, the settled thickness, the 
coverage area, and the number of bags of insulation installed. The 
certification shall be posted in a conspicuous place on the job site.
    102.1.3  Insulation installation. Roof-ceiling, floor, and wall-
cavity insulation shall be installed to permit inspection of the 
manufacturer's R-value identification mark. Alternatively, the 
thickness of roof-ceiling insulation that is blown in or sprayed shall 
be identified by thickness markers that are labeled in meters (inches) 
and installed at least one every 27.9 m2 (300 
ft2) of attic space. The markers shall be affixed to the 
roof trusses or ceiling joists and marked with the minimum installed 
thickness and minimum settled thickness using numbers 25.4 mm (1 in.) 
or greater in height. Each marker shall face the attic access opening. 
The thickness of installed insulation shall meet or exceed the minimum 
installed thickness shown by the marker.
    102.2  Maintenance information. Required regular maintenance 
actions shall be clearly stated on a readily accessible label. Such 
label may be limited to identifying, by title or publication number, 
the operation and maintenance manual for that particular model and type 
of product. Maintenance instructions shall be furnished for equipment 
which requires preventive maintenance for efficient operation.

[[Page 24179]]

    102.3  Fenestration product rating, certification, and labeling. 
Fenestration products (windows, doors, and skylights) purchased by the 
Federal government shall have assigned U-values. If tested for U-value, 
the U-values of fenestration products (windows, doors, and skylights) 
shall be determined in accordance with RS-1, by an accredited, 
independent laboratory. The tested U-value of the fenestration product 
shall be certified and the certified U-value shall be labeled on a 
conspicuous place on the product. Such certified and labeled U-values 
shall be accepted for purposes of determining compliance with the 
building envelope requirements of this part.
    102.3.1  Exception. Where a fenestration product has not been 
assigned a U-value in accordance with RS-1 for a particular product 
line, that product shall be assigned a default U-value in accordance 
with Appendix Tables 102.3.1 and 102.3.2. Product features must be 
technically verifiable for the product to qualify for the U-value 
associated with those features. Where the existence of a particular 
feature cannot be determined with reasonable certainty, the product 
shall not receive credit for that feature. Where a composite of 
materials from two different product types are used, the product shall 
be assigned the higher U-value.


Sec. 435.103  Alternate materials--method of construction, design, or 
insulation systems.

    103.1  The provisions of this part are not intended to prevent the 
use of any material, method of construction, design or insulating 
system not specifically prescribed herein, provided that such 
construction, design or insulating system has been approved as meeting 
the intent of this part.


Sec. 435.104  [Reserved]


Sec. 435.105  [Reserved]


Sec. 435.106  [Reserved]


Sec. 435.107  Precedence.

    107.1  When different sections of this part, or a section of this 
part and a section of a referenced standard from section 801 of this 
part, specify different materials, methods of construction, or other 
requirements, the more stringent or restrictive requirement shall 
govern. Whenever there is a conflict between a general requirement and 
a specific requirement, the specific requirement shall govern.


Sec. 435.108  Life-cycle cost analysis.

    108.1  The proposed building design(s) shall be evaluated in 
accordance with the requirements of the Federal Energy Management 
Program described in subpart A of 10 CFR part 436 to determine its 
life-cycle cost.

Subpart B--Definitions


Sec. 435.201  Definitions.

    For the purposes of this part, certain abbreviations, terms, 
phrases, words and their derivatives shall be set forth in this 
section.
    Accessible (as applied to equipment). Admitting close approach; not 
guarded by locked doors, elevation, or other effective means (see 
``Readily accessible'').
    Addition. Increase in conditioned floor area.
    Air film. Air immediately adjacent to surfaces of building 
materials which helps to inhibit heat flow through those materials.
    Air transport factor. The ratio of the rate of useful sensible heat 
removal from the conditioned space to the energy input to the supply 
and return fan motor expressed in consistent units and under the 
designated operating conditions.
    Attic. A space directly underneath the roof sheathing and directly 
above or adjacent to the interior surfaces of the topmost story of a 
building that satisfies all of the following conditions:
    (1) The structural members comprising the roof are separate and 
distinct rafters and ceiling joists or truss assemblies;
    (2) The space is ventilated in accordance with the requirements of 
the applicable building code;
    (3) The clear height from the top of the ceiling joists to the 
highest point of the underside of the rafters is greater than 0.762 m 
(30 in.); and
    (4) The space is provided with a readily accessible access in 
accordance with the requirements of the applicable building code.
    Automatic. Self-acting, operating by its own mechanism when 
actuated by some impersonal influence, as, for example, a change in 
current strength, pressure, temperature or mechanical configuration 
(see also ``Manual'').
    Basement wall. The opaque portion of a wall which encloses one side 
of a basement and is partially or totally below grade.
    Building code. The legal instrument which is in effect in a state 
or unit of general purpose local government, the provisions of which 
must be adhered to if a building is to be considered to be in 
conformance with law and suitable for occupancy and use.
    Building envelope. The elements of a building which enclose 
conditioned spaces through which thermal energy may be transferred to 
or from the exterior or to or from spaces located in buildings exempted 
by the provisions of section 101.4.2.
    Comfort air conditioning. The process of treating air so as to 
control simultaneously its temperature, humidity, cleanliness, and 
distribution to meet requirements of the conditioned space.
    Comfort envelope. The area of a psychrometric chart enclosing all 
those conditions described in Figure 1 in Standard RS-2 listed in 
section 801 as being comfortable.
    Conditioned floor area. The horizontal projection of that portion 
of interior space which is contained within exterior walls and which is 
conditioned directly or indirectly by an energy-using system.
    Conditioned space. Space within a building which is provided with 
heated and/or cooled air or surfaces and, where required, with 
humidification or dehumidification means so as to be capable of 
maintaining a space condition falling within the comfort zone set forth 
by Standard RS-2 listed in section 801.
    Cooled space. Space within a building which is provided with a 
positive cooling supply.
    Crawl space wall. The opaque portion of a wall which encloses a 
crawl space and is partially or totally below grade.
    Deadband. The temperature range in which no heating or cooling is 
used.
    Degree day, cooling. A unit, based upon temperature difference and 
time, used in estimating fuel consumption and specifying nominal 
cooling load of a building in summer. For any one day, when the mean 
temperature is greater than 18.3  deg.C (65  deg.F), there exists as 
many degree days as there are Celsius (Fahrenheit) degrees difference 
in temperature between the mean temperature for the day and 18.3  deg.C 
(65  deg.F).
    Degree day, heating. A unit, based upon temperature difference and 
time, used in estimating fuel consumption and specifying nominal 
heating load of a building in winter. For any one day, when the mean 
temperature is less than 18.3  deg.C (65  deg.F), there exists as many 
degree days as there are Celsius (Fahrenheit) degrees difference in 
temperature between the mean temperature for the day and 18.3  deg.C 
(65  deg.F).
    Drain tile loop. A continuous length of drain tile or perforated 
pipe extending around all or part of the internal or external perimeter 
of a basement or crawl space footing.
    Dwelling unit. A single housekeeping unit comprised of one or more 
rooms providing complete independent living

[[Page 24180]]

facilities for one or more persons, including permanent provisions for 
living, sleeping, eating, cooking and sanitation.
    Efficiency, HVAC system. The ratio of useful energy output (at the 
point of use) to the energy input in consistent units for a designated 
time period, expressed in percent.
    Energy. The capacity for doing work taking a number of forms which 
may be transformed from one into another, such as thermal (heat), 
mechanical (work), electrical and chemical in customary units, measured 
in kilowatt-hours (kWh) or Kilojoules [British thermal units (Btus)].
    Energy source. Electricity, natural gas, propane gas or fuel oil 
that is available at a residential building for space heating, space 
cooling, service water heating and lighting. See also ``Renewable 
energy sources.''
    Equipment type. HVAC system equipment or service water heating 
equipment that (1) performs a specific function(s) (e.g., space heating 
or space heating and service water heating), (2) uses a specific energy 
source(s) (e.g., electricity or a ``dual-fuel'' furnace that can use 
electricity or natural gas), and (3) employs a specific operational 
principle (e.g., direct combustion, heat rejection to air, heat 
extraction from ground water). Example: A heat pump water heater is a 
different equipment type from an electric resistance water heater.
    Exterior envelope. See ``Building envelope.''
    Federal agency. Any department, agency, corporation, or other 
entity or instrumentality of the executive branch of the Federal 
government, including the United States Postal Service, the Federal 
National Mortgage Association, and the Federal Home Loan Mortgage 
Corporation.
    Federal residential building. Any detached one- or two-family 
residential dwelling or other residential building or structure, three 
stories or less in height, to be constructed or developed for 
residential occupancy by, or for the use of, any Federal agency that is 
not legally subject to state or local building codes or similar 
requirements.
    Furnace, duct. A furnace normally installed in distribution ducts 
of air conditioning systems to supply warm air for heating and which 
depends on a blower not furnished as part of the duct furnace for air 
circulation.
    Furnace, warm air. A self-contained, indirect-fired or electrically 
heated furnace that supplies heated air through ducts to spaces that 
require it.
    Glazing area. Interior surface area of assemblies that enclose 
conditioned space and that contain glazing, such as windows, sliding 
glass doors, and skylights, including the frame, sash, curbing, 
muntins, and other framing element.
    Grade. The finished ground level adjoining the building at all 
exterior walls.
    Gross area of exterior walls. The normal projection of the building 
envelope wall area bounding interior space which is conditioned by an 
energy-using system, including opaque wall, window and door area. The 
gross area of exterior walls consists of all opaque wall areas, 
including between floor spandrels, peripheral edges of floors, window 
areas including sash, and door areas, where such surfaces are exposed 
to outdoor air, unconditioned spaces, or spaces exempted by section 
101.4.2, and where such spaces enclose a heated or mechanically cooled 
space, including interstitial areas between two such spaces. For each 
basement wall with an average below-grade area less than 50% of its 
total wall area, including openings, the entire wall, including the 
below-grade portion, is included as part of the gross area of exterior 
walls. Nonopaque areas (windows, doors, etc.) of all basement walls are 
included in the gross area of exterior walls.
    Gross floor area. The sum of the areas of the several floors of the 
building, including basements, cellars, mezzanine and intermediate 
floored tiers and penthouses of headroom height, measured from the 
exterior faces of exterior walls or from the center line of walls 
separating buildings, but excluding:
    (a) Covered walkways, open roofed-over areas, porches and similar 
spaces.
    (b) Pipe trenches, exterior terraces or steps, chimneys, roof 
overhangs and similar features.
    Group R Federal residential buildings. For the purpose of this 
part, Group R Federal residential buildings include:
    (a) Type A-1--Detached one and two family dwellings; and,
    (b) Type A-2--Other Federal residential buildings, three stories or 
less in height.
    Heat. The form of energy that is transferred by virtue of a 
temperature difference or a change in state of a material.
    Heat trap. An arrangement of piping connecting to a hot water 
heater such that the piping makes an inverted ``U'' just before 
connecting to the heater fittings. Any other arrangement, including a 
commercially available heat trap, which effectively restricts the 
natural tendency of hot water to rise also qualifies as a heat trap.
    Heated slab. Slab-on-grade construction in which the heating 
elements or hot air distribution system is in contact with or placed 
within the slab or in the subgrade.
    Heated space. Space within a building which is provided with a 
positive heat supply. Finished living space within a basement with 
registers or heating devices designed to supply heat to a basement 
space shall automatically define that space as heated space.
    Humidistat. A regulatory device, actuated by changes in humidity, 
used for automatic control of relative humidity.
    HVAC. Heating, ventilating and air conditioning.
    HVAC system. The equipment, distribution network, and terminals 
that provide, either collectively or individually, the processes of 
heating, ventilating, or air conditioning to a building.
    HVAC system components. HVAC system components provide, in one or 
more factory-assembled packages, means for chilling and/or heating 
water with controlled temperature for delivery to terminal units 
serving the conditioned spaces of the building. Types of HVAC system 
components include, but are not limited to, water chiller packages, 
reciprocating condensing units and water source (hydronic) heat pumps 
(see ``HVAC system equipment'').
    HVAC system efficiency. See ``Efficiency, HVAC system.''
    HVAC system equipment. HVAC system equipment provides, in one 
(single package) or more (split system) factory-assembled packages, 
means for air circulation, air cleaning, air cooling with controlled 
temperature and dehumidification, and, optionally, either alone or in 
combination with a heating plant, the functions of heating and 
humidifying. The cooling function may be either electrically or heat 
operated and the refrigerant condenser may be air, water or 
evaporatively cooled. Where the equipment is provided in more than one 
package, the separate packages shall be designed by the manufacturer to 
be used together. The equipment may provide the heating function as a 
heat pump or by the use of electric or fossil-fuel-fired elements. (The 
word ``equipment'' used without modifying adjective may, in accordance 
with common industry usage, apply either to HVAC system equipment or 
HVAC system components.)
    Infiltration. The uncontrolled inward air leakage through cracks 
and interstices in any building element and around windows and doors of 
a

[[Page 24181]]

building caused by the pressure effects of wind and/or the effect of 
differences in the indoor and outdoor air density.
    Life-cycle cost. The total discounted cost of owning, operating, 
and maintaining a building or piece of equipment over its useful life 
(including its fuel, energy, labor, and replacement components) 
determined on the basis of a systematic evaluation except that in the 
case of leased buildings, the life-cycle cost shall be calculated over 
the effective remaining term of the lease.
    Manual. Capable of being operated by personal intervention (see 
``Automatic'').
    Multi-family dwelling. A building containing three or more dwelling 
units.
    Opaque areas. All exposed areas of a building envelope which 
enclose conditioned space, except openings for windows, skylights, 
doors and building service systems.
    Outdoor air. Air taken from the outdoors and, therefore, not 
previously circulated through the system.
    Packaged terminal air conditioner. A factory-selected wall sleeve 
and separate unencased combination of heating and cooling components, 
assemblies or sections intended for mounting through the wall to serve 
a single room or zone. It includes heating capability by hot water, 
steam, or electricity.
    Packaged terminal heat pump. A packaged terminal air conditioner 
capable of using the refrigeration system in a reverse cycle or heat 
pump mode to provide heat.
    pCi/L. The abbreviation for ``picocuries per liter,'' which is used 
as a measure for radon concentrations in air. A picocurie is one-
trillionth (10-12) of a curie. A ``curie'' is a commonly 
used measurement of radioactivity.
    Positive cooling supply. Mechanical cooling deliberately supplied 
to a space such as through a supply register. Also, mechanical cooling 
indirectly supplied to a space through uninsulated surfaces of space-
cooling components, such as evaporator coil cases and cooling 
distribution systems which continually maintain air temperatures within 
the space of 29.4  deg.C (85  deg.F) or lower during normal operation. 
To be considered exempt from inclusion in this definition, such 
surfaces shall comply with the insulation requirements of this part.
    Positive heat supply. Heat deliberately supplied to a space by 
design, such as a supply register, radiator or heating element. Also, 
heat indirectly supplied to a space through uninsulated surfaces of 
service water heaters and space heating components, such as furnaces, 
boilers and heating and cooling distribution systems which continually 
maintain air temperature within the space of 10  deg.C (50  deg.F) or 
higher during normal operation. To be considered exempt from inclusion 
in this definition, such surfaces shall comply with the insulation 
requirements of this part.
    Proposed design. A building design submitted in response to a 
request for proposals for the construction of a new Federal residential 
building.
    Readily accessible. Capable of being reached quickly for operation, 
maintenance, removal, or inspection, without requiring the need to 
climb over or remove obstacles or to resort to portable ladders or 
chairs (see ``Accessible'').
    Renewable energy sources. Sources of energy (excluding minerals) 
derived from incoming solar radiation, including natural daylighting 
and photosynthetic processes; from phenomena resulting therefrom, 
including wind, waves and tides, lake or pond thermal differences; and 
from the internal heat of the earth, including nocturnal thermal 
exchanges.
    Reset. Adjustment of the set point of a control instrument to a 
higher or lower value automatically or manually to conserve energy.
    Roof assembly. All components of the roof/ceiling envelope through 
which heat flows, thus creating a building transmission heat loss or 
gain, where such assembly is exposed to outdoor air and encloses a 
heated or mechanically cooled space. The gross area of a roof assembly 
consists of the total interior surface of such assembly, including 
skylights exposed to the heated or mechanically cooled space.
    Sash crack. The sum of all perimeters of all window sashes, based 
on overall dimensions of such parts, expressed in meters (feet). If a 
portion of one sash perimeter overlaps a portion of another sash 
perimeter, only count the length of the overlapping portions once.
    Sensible capacity. The maximum sensible load for which a piece of 
equipment is designed to remove or add sensible heat.
    Sensible load. The cooling or heating load to remove or add the 
sensible heat that causes a temperature change.
    Service systems. All energy-using systems in a building that are 
operated to provide services for the occupants or processes housed 
therein, including HVAC, service water heating, illumination, 
transportation, cooking or food preparation, laundering or similar 
functions.
    Service water heating. Supply of hot water for purposes other than 
comfort heating.
    Slab-on-grade floor insulation. Insulation around the perimeter of 
the floor slab or its supporting foundation when the top edge of the 
floor slab perimeter is above the finished grade or 0.305 m (12 in.) or 
less below the finished grade.
    Soil gas. The gas, present in soil, which may contain radon.
    Soil gas retarder. A continuous membrane or other comparable 
material used to retard the flow of soil gas into a building.
    Solar energy source. Source of natural daylighting and of thermal, 
chemical or electrical energy derived directly from conversion of 
incident solar radiation.
    Standard design. A building designed to exactly meet but not exceed 
all requirements in Subpart E of this part.
    Submembrane depressurization system. A system designed to achieve a 
lower air pressure beneath the soil gas retarder in a crawl space, 
relative to crawl space air pressure, resulting in air withdrawal from 
under the soil gas retarder either passively (relying on the upward 
convective flow of air) or actively (by use of a fan-powered vent).
    Subslab depressurization system (active). A piping system that 
connects the subslab area with outdoor air, is routed through the 
conditioned space of a building, and uses a fan-powered vent to draw 
air from beneath the slab.
    Subslab depressurization system (passive). A piping system that 
connects the subslab area with outdoor air, is routed through the 
conditioned space of a building, and relies on the convective flow of 
air to draw air from beneath the slab.
    Supplementary heater operation. The auxiliary electric resistance 
heating device that provides heat which contributes to the operation of 
the heat pump when the temperature is too low for the heat pump to 
operate independently.
    System. A combination of central or terminal equipment or 
components and/or controls, accessories, interconnecting means, and 
terminal devices by which energy is transformed so as to perform a 
specific function, such as HVAC, service water heating or illumination.
    Technically verifiable. To visually, physically, or through testing 
determine the physical characteristics or specifications of an element, 
material, or object.
    Terminal element. The means by which the transformed energy from a 
system is finally delivered; i.e., registers, diffusers, lighting 
fixtures, faucets and similar elements.
    Thermal conductance. Time rate of heat flow through a body 
(frequently per unit area) from one bounding surface to

[[Page 24182]]

the other for a unit temperature difference between the two surfaces, 
under steady conditions (W/m2 deg.C) [Btu/
(hft2 deg.F)].
    Thermal resistance (R). The reciprocal of thermal conductance 
(m2 deg.C/W) 
[(hft2 deg.F)/Btu].
    Thermal transmittance (U). The coefficient of heat transmission 
(air to air). It is the time rate of heat flow per unit area and unit 
temperature difference between the warm side and cold side air films 
(W/m2 deg.C) [Btu/
(hft2 deg.F)]. The U-value applies to 
combinations of different materials used in series along the heat flow 
path, single materials that comprise a building section, cavity air 
spaces and surface air films on both sides of a building element.
    Thermal transmittance, overall (Uo). The overall 
(average) heat transmission of a gross area of exterior building 
envelope (W/m2 deg.C) [Btu/
(hft2 deg.F)]. The Uo value 
applies to the combined effect of the time rate of heat flow through 
the various parallel paths such as windows, doors and opaque 
construction areas, comprising the gross area of one or more exterior 
building components, such as walls, floors or roof/ceilings.
    Thermostat. An automatic control device actuated by temperature and 
designed to be responsive to temperature.
    Unitary cooling and heating equipment. One or more factory-made 
assemblies which include an evaporator or cooling coil, a compressor 
and condenser combination, and may include a heating function as well. 
Where such equipment is provided in more than one assembly, the 
separate assemblies shall be designed to be used together.
    Unitary heat pump. One or more factory-made assemblies which 
include an indoor conditioning coil, compressor(s) and outdoor coil or 
refrigerant-to-water heat exchanger, including means to provide both 
heating and cooling functions. When such equipment is provided in more 
than one assembly, the separate assemblies shall be designed to be used 
together.
    Ventilation. The process of supplying or removing air by natural or 
mechanical means to or from any space. Such air may have been 
conditioned.
    Ventilation air. That portion of supply air which comes from 
outside (outdoors) plus any recirculated air that has been treated to 
maintain the desired quality of air within a designated space. (See 
Standard RS-3 listed in section 801 of this part, and definition of 
``Outdoor air''.)
    Walls. Those portions of the building envelope which are vertical 
or tilted at an angle of 30 deg. or less from the vertical plane.
    Zone. A space or group of spaces within a building with heating 
and/or cooling requirements sufficiently similar so that comfort 
conditions can be maintained throughout by a single controlling device.

Subpart C--Design Conditions


Sec. 435.301  Scope.

    301.1  General. The criteria of this subpart establishes the design 
conditions for use with Subparts D and E of this part.


Sec. 435.302  Thermal design parameters.

    302.1  Exterior design conditions. The following design parameters 
from table 302.1 shall be used for calculations required under this 
part.

                                                   Table 302.1                                                  
                                          [Exterior design conditions]                                          
----------------------------------------------------------------------------------------------------------------
                                                                                                                
----------------------------------------------------------------------------------------------------------------
Winter \1\.............................  Design Dry-bulb.....................   deg.C ( deg.F).                 
Summer \1\.............................  Design Dry-bulb.....................   deg.C ( deg.F).                 
                                         Design Wet-bulb.....................   deg.C ( deg.F).                 
Degree days, heating \2\                                                                                        
Degree days, cooling \2\                                                                                        
----------------------------------------------------------------------------------------------------------------
\1\ The outdoor design temperature shall be selected from the columns of 97.5% values for winter and 2.5% values
  for summer from tables in Standard RS-4 listed in section 801. Adjustments may be made to reflect local       
  climates which differ from the tabulated temperatures, or local weather experience.                           
\2\ The degree days, heating [base 18.3 deg.C (65 deg.F)] and cooling [base 18.3 deg.C (65 deg.F)] shall be     
  selected from NOAA Annual Degree Days to Selected Bases Derived from the 1961--1990 Normals, Standard RS-4    
  listed in section 801, data available from adjacent military installations, or other sources of local data.   

    302.2  Interior design conditions.
    302.2.1  Indoor Design Temperature. Indoor design temperature shall 
be 22.2 deg.C (72 deg.F) for heating and 25.6 deg.C (78 deg.F) for 
cooling.
    302.2.2  Exception. Other design temperatures may be used for 
equipment selection if it results in a lower energy usage.


Sec. 435.303  Mechanical ventilation criteria.

    303.1  Ventilation. Ventilation air shall conform to Standard RS-3 
listed in section 801. The minimum column value of Standard RS-3 for 
each type of occupancy shall be used for design. The ventilation 
quantities specified in section 6 of Standard RS-3 are for 100% outdoor 
air ventilating systems.
    303.1.1  Exception. If outdoor air quantities other than those 
specified in Standard RS-3 are used or required because of special 
occupancy or process requirements, source control of air contamination, 
health and safety or other standards, the required outdoor air 
quantities shall be used as the basis for calculating the heating and 
cooling design loads.

Subpart D--Design by Systems Analysis; Design Utilizing Renewable 
Energy Sources


Sec. 435.401  Scope.

    401.1  General. This subpart establishes design requirements based 
on a systems analysis of total energy use by a new Federal residential 
building, including all of its systems. These design requirements may 
be applied as an alternative to the component performance requirements 
established in subpart E.


Sec. 435.402  Systems analysis.

    402.1 Energy analysis. Compliance with this subpart requires an 
analysis of the annual energy usage, hereinafter called an annual 
energy analysis. The proposed building shall utilize a design that is 
demonstrated, through technically valid and documented calculations, to 
have equal or lower annual energy use and equal or lower life-cycle 
costs than the standard design.
    (a) A building designed in accordance with this subpart complies 
with this part if the calculated annual energy usage and life-cycle 
costs are not greater than a similar building (defined as a ``standard 
design'') with building thermal envelope components and mechanical 
systems and equipment used to provide heating, ventilating, and air-
conditioning designed in accordance with subpart E.

[[Page 24183]]

    (b) For a proposed building to be considered similar to a 
``standard design,'' the proposed building shall have the same 
conditioned floor area, ratio of thermal envelope area to conditioned 
floor area, exterior design conditions, occupancy, climate data, and 
usage operational schedule.
    (c) The proposed design shall use the same energy source(s) for 
space heating, space cooling, and domestic water heating as the 
standard design (identified in subpart E).
    402.1.1  Input values for Group R buildings. The input values/
assumptions from tables 402.1.1a through 402.1.1g shall be used in 
calculating the annual energy usage.

                             Table 402.1.1a                             
                            [Glazing systems]                           
------------------------------------------------------------------------
                            Input Assumptions                           
-------------------------------------------------------------------------
         Design Parameter             Standard Design    Proposed Design
------------------------------------------------------------------------
Glazing Orientation..............  Window area of        Window area    
                                    proposed house, 25%   oriented as   
                                    on North, South,      proposed      
                                    East, and West        design.       
                                    Exterior walls..                    
Shading..........................  Draperies shall be    Any exterior   
                                    assumed to be         shading       
                                    closed during         provided by   
                                    period of             proposed      
                                    mechanical air        design.       
                                    conditioner                         
                                    operation..                         
------------------------------------------------------------------------


                             Table 402.1.1b                             
                      [Heat storage (thermal mass)]                     
------------------------------------------------------------------------
                                                                        
------------------------------------------------------------------------
Internal mass..................  39.0 kg/m\2\ (8 lb/ft \2\)             
Structural mass................  17.1 kg/m\2\ (3.5 lb/ft \2\)           
------------------------------------------------------------------------


                             Table 402.1.1c                             
          [Building thermal envelope--surface areas and volume]         
------------------------------------------------------------------------
            Design parameter                    Input assumptions       
------------------------------------------------------------------------
Floor, walls, ceiling..................  The floor, walls, and ceiling  
                                          areas for both the standard   
                                          and proposed design(s) shall  
                                          be equal.                     
Foundation and floor type..............  The foundation and floor type  
                                          for both the standard and the 
                                          proposed design(s) shall be   
                                          equal.                        
Glazings, including skylights..........  The area of glazing in the     
                                          standard design shall not be  
                                          greater than the area of      
                                          glazing in the proposed       
                                          design(s). The glazing U-value
                                          of the standard design shall  
                                          be selected to permit         
                                          calculated Uo-wall compliance 
                                          of the standard design.       
                                         Glazing area in the standard   
                                          design shall not be provided  
                                          with extra shading beyond     
                                          shading that is provided by   
                                          typical construction          
                                          practices--such as roof       
                                          overhangs. Energy performance 
                                          impacts of added shading for  
                                          glazing areas may be accounted
                                          for in the proposed design(s) 
                                          for a specific building.      
                                          Results from shading          
                                          calculation on one proposed   
                                          building shall not be used for
                                          groups of buildings.          
Doors of A-1 structures................  The standard design shall have 
                                          at least 3.7 m \2\ (40 ft \2\)
                                          of door area.                 
Building Volume........................  The volumes of both the        
                                          standard and proposed         
                                          design(s) shall be equal.     
------------------------------------------------------------------------


                             Table 402.1.1d                             
                        [Thermostat (constants)]                        
------------------------------------------------------------------------
           Design parameter                        Input value          
------------------------------------------------------------------------
Heating Set Point.....................  20.0  deg.C (68  deg.F).        
Cooling Set Point.....................  25.6 *C (78 *F).                
Night Set Back........................  15.6 *C (60 *F).                
Set Back Duration.....................  7 hours.                        
Number of Set-back Periods............  1 (night time).                 
Maximum number of zones...............  2.                              
Number of thermostats per zone........  1.                              
------------------------------------------------------------------------


                             Table 402.1.1e                             
               [Internal Sensible Heat Gains (Constants)]               
------------------------------------------------------------------------
             Unit type                           Input value            
------------------------------------------------------------------------
A-1 Units..........................  440 W (1,500 Btu/h)                
A-2 Units..........................  879 W (3,000 Btu/h)                
------------------------------------------------------------------------


                             Table 402.1.1f                             
             [Domestic Water Heater (Constant, Calculation)]            
------------------------------------------------------------------------
            Design parameter                       Input value          
------------------------------------------------------------------------
Temperature set point..................  49  deg.C (120  deg.F)         
Daily hot water consumption............  Liters=113.7 x n-units+(37.9 x 
                                          n-bedrooms); [Gallons=(30 x n-
                                          units)+(10 x n-bedrooms)]     
------------------------------------------------------------------------
Note:                                                                   
n-units=number of living units in proposed design(s)                    
n-bedrooms=number of bedrooms in each living unit.                      


                             Table 402.1.1g                             
                   [Distribution System Loss Factors]                   
------------------------------------------------------------------------
                              Duct Location                             
-------------------------------------------------------------------------
                         Mode                           Outside   Inside
------------------------------------------------------------------------
Heating..............................................      0.75     1.00
Cooling..............................................      0.80     1.00
------------------------------------------------------------------------

    402.1.2  If the proposed design takes credit for reduced air 
changes per hour levels, documentation of measures providing such 
reduction, or results of a post-construction blower-door test shall be 
demonstrated using Standard RS-5 listed in section 801.
    402.1.3  Passive solar building designs shall have fixed external 
shading, operable internal or external shading or other shading 
technologies to limit excessive summer cooling energy gains to the 
building interior.
    402.1.4  Passive solar buildings shall utilize at least 919 kJ/ 
deg.C (45 Btu/ deg.F) of additional thermal mass, per m2 
(ft\2\) of added glass area, when added south-facing glass area exceeds 
33% of the total glass area in walls.
    402.1.5  Site Weather Data (constants).
    402.1.5.1  The typical meteorological year (TMY), or its ``ersatz'' 
equivalent, from the National Oceanic and Atmospheric Administration 
(NOAA), or an approved equivalent, for the closest available location 
shall be used.
    402.1.6  The HVAC System Efficiency, for heating and cooling mode, 
as identified in 10 CFR part 430 shall be proportionally adjusted for 
those portions of the ductwork located outside or inside the 
conditioned space using the values shown above, in accordance with 
equation 402.1a and table 402.1g:

(Equation 402.1.6a)


[[Page 24184]]


Total Adjusted System Efficiency=Equipment Efficiency  x  Distribution 
Loss Factor  x  percent of ducts outside+Equipment Efficiency  x  
Distribution Loss Factor  x  percent of ducts inside.
    402.1.7  Air infiltration. Air changes per hour for the standard 
design is 0.5 (for purposes of calculation only).
    402.2  Design. The energy usage of the standard design and the 
proposed design shall be compared as follows:
    (a) The comparison shall be expressed as joule per square meter 
(Btu input per square foot) of gross floor area per year at building 
site.
    (b) If the proposed design results in an increase in usage of one 
energy source and a decrease in another energy source, even though 
similar sources are used for similar purposes, the difference in each 
energy source shall be converted to equivalent energy units for 
purposes of comparing the total energy used.
    (c) The different energy sources shall be compared on the basis of 
energy use at the site where: 1 kWh=3,413 Btu.
    402.3  Analysis procedure. The analysis of the annual energy usage 
of the standard design and the proposed design(s) shall meet the 
following criteria:
    (a) The building heating/cooling load calculation procedure used 
for annual energy usage analysis shall be detailed enough to evaluate 
the effect of factors specified in section 402.4.
    (b) The calculation procedure used to simulate the operation of the 
building and its service systems through a full-year operating period 
shall evaluate the effect of system design, climatic factors, 
operational characteristics, and mechanical equipment on annual energy 
usage. Manufacturer's data or comparable field test data shall be used 
when available in the simulation of systems and equipment. The 
calculation procedure shall be based upon 8,760 hours of operation of 
the building and its service systems and shall utilize the design 
methods specified in Standards RS-4, -6, and -7 listed in section 801.
    402.4  Calculation procedures. The calculation procedure shall 
cover the following items:
    (a) Design requirements--Environmental requirements as required in 
subpart C.
    (b) Climatic data--Coincident hourly data for temperatures, solar 
radiation, wind and humidity of typical days in the year representing 
seasonal variation.
    (c) Building data--Orientation, size, shape, mass, air, moisture 
and heat transfer characteristics.
    (d) Operational characteristics--Temperature, humidity, 
ventilation, illumination, control mode for occupied and unoccupied 
hours.
    (e) Mechanical equipment--Design capacity, part load profile.
    (f) Building loads--Internal heat generation, lighting, equipment, 
number of people during occupied and unoccupied periods.
    402.4.1  Use of approved calculation tool. The same calculation 
tool shall be used to estimate the annual energy usage for space 
heating and cooling of the standard design and the proposed design(s).
    402.5  Documentation. Proposed design(s) shall have an energy 
analysis comparison report providing technical detail on the data used 
in and resulting from the comparative analysis to verify that both the 
analysis and the designs meet the criteria of section 401 of this part.
    402.6  Exception. Proposed design(s) for one and two family 
dwellings and multifamily buildings having a conditioned floor area of 
465 m\2\ (5,000 ft\2\) or less are exempted from performing an analysis 
on a full-year (8760 hours) basis as described in section 402.3(b). 
However, comparison of heating, cooling, and service water heating 
equipment energy usage between the proposed design(s) and the standard 
design shall be provided in accordance with the remaining provisions of 
section 402 of this part.


Sec. 435.403  Renewable energy source analysis.

    403.1  General. A proposed building utilizing solar, geothermal, 
wind or other renewable energy sources for all or part of its energy 
source shall meet the requirements of section 402 of this part, except 
such renewable energy may be excluded from the total annual energy 
usage allowed for the building by that section.
    403.1.1  To qualify for this exclusion such renewable energy must 
be derived from a specific collection, storage and distribution system. 
The solar energy passing through windows shall also be considered as 
qualifying if such windows are provided with:
    (a) Operable insulating shutters or other devices which, when drawn 
or closed, shall cause the window area to reduce maximum outward heat 
flow rate to that specified in section 502.3.1; and
    (b) The window areas are shaded or otherwise protected from direct 
rays of the sun during periods when mechanical cooling is required.
    403.1.2  Exclusion shall also be granted for solar energy passing 
through windows provided:
    (a) The glass is double or triple pane insulating glass with a low-
emittance coating on one or more airspace surfaces of the glass, or 
with a low-emittance plastic film suspended in the airspace, and
    (b) The glass areas are shaded from direct solar radiation during 
periods when mechanical cooling is required.
    403.1.3  Other criteria covered in section 402 shall apply to the 
proposed design(s) utilizing renewable sources of energy.
    403.2  Documentation. An annual energy analysis comparison shall be 
prepared comparing the proposed design(s) and the standard design as 
specified in section 402. The report shall provide technical detail on 
the building and system design(s) and on the data employed in the 
comparative analysis sufficient to verify that both the analysis and 
the proposed design(s) meet the criteria of sections 402 and 403 of 
this part.
    403.2.1  The energy derived from renewable sources and the 
reduction in conventional energy requirements derived from nocturnal 
cooling shall be separately identified from the overall building energy 
use. Supporting documentation on the basis of the performance estimates 
for the renewable energy sources or nocturnal cooling shall be 
demonstrated in the building plans and specifications.
    403.2.2  Energy usage must be calculated in accordance with the 
design conditions and methods specified in this part.
    403.3  Exception. Proposed design(s) for buildings of less than 
464m2 (5,000 ft2) of conditioned floor area that 
derive a minimum of 30% of their total annual energy usage from 
renewable sources or from nocturnal cooling are exempt from performing 
the analysis on a full-year (8,760 hours) basis as described in section 
402.3(b). However, comparison of heating, cooling, and service water 
heating equipment energy usage between the proposed design(s) and the 
standard design shall be provided in accordance with the remaining 
provisions of sections 402 and 403 of this part.
    403.4  Passive solar design analysis. Proposed design(s) using 
passive solar heating strategies, such as south window placement 
coupled with thermal mass, attached greenhouses or sunspaces, or Trombe 
walls, can be analyzed for annual heating and cooling loads using RS-8. 
Other methods for analysis of solar design strategies and equipment are 
permitted. Note that use of RS-8 provides information on building loads 
only; actual energy consumption depends on the equipment

[[Page 24185]]

proposed for installation in the building.

Subpart E--Design by Component Performance Approach


Sec. 435.501  Scope.

    501.1  General. This subpart establishes design requirements based 
on component performance for new Federal residential buildings. The 
design requirements established in subpart D may be applied in lieu of 
these requirements.


Sec. 435.502  Building thermal envelope requirements.

    502.1  General. The building thermal envelope shall meet the 
requirements of table 502.1a. Compliance with these requirements shall 
be demonstrated in accordance with section 502.2. To demonstrate 
compliance, calculation procedures and information contained in RS-4, 
or laboratory test measurements obtained from test methods RS-9, -10, -
11, or -12, or other documented procedures or information, shall be 
used.
    502.1.1  The proposed design may include the use of thermal mass in 
the exterior walls when determining energy use. If the use of thermal 
mass is considered appropriate in the design of the exterior walls then 
the required UW for exterior walls, covered by section 
502.2.1.1 and having a heat capacity greater than or equal to 123 kJ/
m2 deg.K (6 Btu/ft2 deg.F), 
shall be less than or equal to the U-value determined by the applicable 
heating degree-days and low-mass-wall UW in tables 502.1b, 
502.1c, or 502.1d. The column headings in tables 502.1b through 502.1d 
are the UW's, as determined by using equation 502.2a and 
Appendix Figure 1, for low-mass-walls; wall constructions having a heat 
capacity of less than 123 kJ/m2 deg.K (6 Btu/
ft2 deg.F), as determined by equation 502.1a. The 
heat capacity of the wall shall be determined by using equation 502.1a 
below:

(Equation 502.1a)

HC=w x c

where:

 HC=heat capacity of the exterior wall, based on exterior surface area, 
W/(m2 deg.K) [Btu/(ft2 deg.F)].
w=mass of the wall, based on exterior surface area, kg/m2 
(lb/ft2).
c=specific heat of the exterior wall material, kJ/(kg deg.K) 
[Btu/(lb deg.F)].

    The specific heat values shall be permitted to be obtained from 
Chapter 22 of Standard RS-4.

                                                Table 502.1a \1\                                                
----------------------------------------------------------------------------------------------------------------
             Element                          Mode               Type A-1  buildings       Type A-2 buildings   
----------------------------------------------------------------------------------------------------------------
Walls............................  Heating or cooling.......  Uo                        Uo                      
Roof/Ceiling.....................  Heating or cooling.......  Uo                        Uo                      
Floors over unheated spaces......  Heating or cooling.......  Uo                        Uo                      
Heated slab on grade 2 5.........  Heating..................  R                         R                       
                                                              Depth  in.\6\             Depth  in.\6\           
Unheating slab on grade 3 5......  Heating..................  R                         R                       
                                                              Depth  in.\6\             Depth  in.\6\           
Basement wall 4 5................  Heating or cooling.......  U                         U                       
Crawl space wall 4 5.............  Heating or cooling.......  U                         U                       
----------------------------------------------------------------------------------------------------------------
\1\ Values shall be determined by using the graphs (Figures 1, 2, 3, 4, 5 and 6) contained in the Appendix of   
  this part using heating degree days as specified in section 302.                                              
\2\ There are no insulation requirements for heated slabs in locations having less than 278 Celsius heating     
  degree days (500 Fahrenheit HDD).                                                                             
\3\ There are no insulation requirements for unheated slabs in locations having less than 1,389 Celsius heating 
  degree days (2,500 Fahrenheit HDD).                                                                           
\4\ Basement and crawl space wall U-values shall be based on the wall components and surface air films. Adjacent
  soil shall not be considered in the determination of the U-value.                                             
\5\ Typical foundation wall insulation techniques can be found in Standard RS-13.                               
\6\ Depth of burial measured as described in section 502.2.1.4.                                                 


    Table 502.1b.--Required Uw for Wall With a Heat Capacity Equal To or Exceeding 123 kJ/(m2   deg.K) [6 Btu/(ft2  deg.F)] With    
                                                   Insulation Placed on the Exterior of the Wall Mass                                                   
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                              UW required for walls with a heat capacity less than 123 kJ/(m2   deg.K)  [6 Btu/(ft2 
                                                                  deg.F)] as determined by using equation 502.2a and appendix figure 1                  
Heating degree days  18.3  deg.C (65  deg.F) -----------------------------------------------------------------------------------------------------------
                    base                         1.13        1.02        0.90        0.79        0.68        0.56        0.45        0.34        0.22   
                                                (0.20)      (0.18)      (0.16)      (0.14)      (0.12)      (0.10)      (0.08)      (0.06)      (0.04)  
--------------------------------------------------------------------------------------------------------------------------------------------------------
0-1111......................................       1.59        1.47        1.30        1.19        1.02        0.90        0.73        0.62        0.45 
(0-2000)....................................      (0.28)      (0.26)      (0.23)      (0.21)      (0.18)      (0.16)      (0.13)      (0.11)      (0.08)
1112-2222...................................       1.53        1.42        1.24        1.13        0.96        0.85        0.73        0.56        0.45 
(2001-4000).................................      (0.27)      (0.25)      (0.22)      (0.20)      (0.17)      (0.15)      (0.13)      (0.10)      (0.08)
2223-3056...................................       1.42        1.30        1.19        1.02        0.90        0.79        0.62        0.51        0.39 
(4001-5500).................................      (0.25)      (0.23)      (0.21)      (0.18)      (0.16)      (0.14)      (0.11)      (0.09)      (0.07)
3056-3611...................................       1.30        1.19        1.07        0.96        0.85        0.68        0.56        0.45        0.34 
(5501-6500).................................      (0.23)      (0.21)      (0.19)      (0.17)      (0.15)      (0.12)      (0.10)      (0.08)      (0.06)
3612-4444...................................       1.24        1.07        0.96        0.85        0.73        0.62        0.51        0.39        0.28 
(6501-8000).................................      (0.22)      (0.19)      (0.17)      (0.15)      (0.13)      (0.11)      (0.09)      (0.07)      (0.05)
>4445.......................................       1.13        1.02        0.90        0.79        0.68        0.56        0.45        0.34        0.22 
(>8001).....................................      (0.20)      (0.18)      (0.16)      (0.14)      (0.12)      (0.10)      (0.08)      (0.06)      (0.04)
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 24186]]


 Table 502.1c.--Required Uw for Wall With a Heat Capacity Equal To or Exceeding 123kJ/(m2 deg.K) [6Btu/(ft2  deg.F) With Insulation 
                                                         Placed on the Interior of the Wall Mass                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                               Uw required for walls with a heat capacity less than 123 kJ/(m2   deg.K) [6 Btu/(ft2 
                                                                 deg.F)] as determined by using equation 502.2a and appendix figure 1                   
 Heating degree days  18.3 deg.C (65 deg.F)  -----------------------------------------------------------------------------------------------------------
                    base                         1.13        1.02        0.90        0.79        0.68        0.56        0.45        0.34        0.22   
                                                (0.20)      (0.18)      (0.16)      (0.14)      (0.12)      (0.10)      (0.08)      (0.06)      (0.04)  
--------------------------------------------------------------------------------------------------------------------------------------------------------
0-1111......................................       1.42        1.24        1.13        0.96        0.85        0.68        0.51        0.39        0.22 
(0-2000)....................................      (0.25)      (0.22)      (0.20)      (0.17)      (0.15)      (0.12)      (0.09)      (0.07)      (0.04)
1112-2222...................................       1.36        1.19        1.07        0.90        0.79        0.68        0.51        0.39        0.22 
(2001-4000).................................      (0.24)      (0.21)      (0.19)      (0.16)      (0.14)      (0.12)      (0.09)      (0.07)      (0.04)
2223-3056...................................       1.30        1.19        1.07        0.90        0.79        0.62        0.51        0.39        0.22 
(4001-5500).................................      (0.23)      (0.21)      (0.19)      (0.16)      (0.14)      (0.11)      (0.09)      (0.07)      (0.04)
3056-3611...................................       1.24        1.13        0.96        0.85        0.73        0.62        0.51        0.34        0.22 
(5501-6500).................................      (0.22)      (0.20)      (0.17)      (0.15)      (0.13)      (0.11)      (0.09)      (0.06)      (0.04)
3612-4444...................................       1.19        1.07        0.96        0.79        0.68        0.56        0.45        0.34        0.22 
(6501-8000).................................      (0.21)      (0.19)      (0.17)      (0.14)      (0.12)      (0.10)      (0.08)      (0.06)      (0.04)
>4445.......................................       1.13        1.02        0.90        0.79        0.68        0.56        0.45        0.34        0.22 
(>8001).....................................      (0.20)      (0.18)      (0.16)      (0.14)      (0.12)      (0.10)      (0.08)      (0.06)      (0.04)
--------------------------------------------------------------------------------------------------------------------------------------------------------


  Table 502.1d.--Required Uw for Wall With a Heat Capacity Equal To or Exceeding 123kJ/(m2   deg.K) [6Btu/(ft2 deg.F) With Integral 
                                               Insulation (Insulation and Mass Mixed, Such as a Log Wall)                                               
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                               Uw required for walls with a heat capacity less than 123 kJ/(m2   deg.K) [6 Btu/(ft2 
                                                                 deg.F)] as determined by using equation 502.2a and appendix figure 1                   
 Heating degree days  18.3 deg.C (65 deg.F)  -----------------------------------------------------------------------------------------------------------
                    base                         1.13        1.02        0.90        0.79        0.68        0.56        0.45        0.34        0.22   
                                                (0.20)      (0.18)      (0.16)      (0.14)      (0.12)      (0.10)      (0.08)      (0.06)      (0.04)  
--------------------------------------------------------------------------------------------------------------------------------------------------------
0-1111......................................       1.59        1.42        1.30        1.13        0.96        0.85        0.68        0.51        0.39 
(0-2000)....................................      (0.28)      (0.25)      (0.23)      (0.20)      (0.17)      (0.15)      (0.12)      (0.09)      (0.07)
1112-2222...................................       1.53        1.36        1.24        1.07        0.96        0.79        0.62        0.51        0.34 
(2001-4000).................................      (0.27)      (0.24)      (0.22)      (0.19)      (0.17)      (0.14)      (0.11)      (0.09)      (0.06)
2223-3056...................................       1.47        1.30        1.19        1.02        0.90        0.73        0.62        0.45        0.34 
(4001-5500).................................      (0.26)      (0.23)      (0.21)      (0.18)      (0.16)      (0.13)      (0.11)      (0.08)      (0.06)
3056-3611...................................       1.36        1.19        1.07        0.96        0.79        0.68        0.56        0.45        0.28 
(5501-6500).................................      (0.24)      (0.21)      (0.19)      (0.17)      (0.14)      (0.12)      (1.10)      (0.08)      (0.05)
3612-4444...................................       1.24        1.13        1.02        0.85        0.73        0.62        0.51        0.39        0.28 
(6501-8000).................................      (0.22)      (0.20)      (0.18)      (0.15)      (0.13)      (0.11)      (0.09)      (0.07)      (0.05)
>4445.......................................       1.13        1.02        0.90        0.79        0.68        0.56        0.45        0.34        0.22 
(>8001).....................................      (0.20)      (0.18)      (0.16)      (0.14)      (0.12)      (0.10)      (0.08)      (0.06)      (0.04)
--------------------------------------------------------------------------------------------------------------------------------------------------------

    502.1.2  The design shall not create conditions of accelerated 
deterioration from moisture condensation. For frame walls, floors, and 
ceilings not ventilated to allow moisture to escape, an approved vapor 
retarder having a maximum perm rating of 57.4 ng/
Pasm2 (1.0 perm), when tested in 
accordance with Standard RS-14, Procedure A, shall be installed on the 
warm-in-winter side of the thermal insulation.
    502.1.3  Exceptions.
    502.1.3.1  Buildings are exempt from the requirements of section 
502.1.2 in construction where moisture or its freezing will not damage 
the materials.
    502.1.3.2  Buildings are exempt from the requirements of section 
502.1.2 in hot and humid climate areas where the following conditions 
occur:
    (a) 19.4  deg.C (67  deg.F) or higher wet-bulb temperature for 
3,000 or more hours during the warmest six consecutive months of the 
year, and/or
    (b) 22.8  deg.C (73  deg.F) or higher wet-bulb temperature for 
1,500 or more hours during the warmest six consecutive months of the 
year.
    502.1.4  Access openings. Access doors, hatches, scuttles, pull-
down staircases and similar constructions separating a conditioned from 
an unconditioned space shall be weatherstripped along the surfaces that 
seal to the surrounding fixed frame. The access opening shall be 
insulated to a level equivalent to the insulation of the surrounding 
floor, wall, and ceiling.
    502.1.4.1  Exception. If the access opening is uninsulated, the U-
value of the surrounding floor, wall, and ceiling shall be decreased in 
accordance with equations 502.2a, 502.2b, 502.2c, or 502.2d, as 
appropriate.
    502.1.5  Masonry Veneer. When insulation is placed on a foundation 
wall, and part of the foundation wall supports a masonry veneer for the 
exterior wall, the horizontal portion of the foundation supporting the 
veneer need not be insulated.
    502.2  Heating and cooling criteria.
    502.2.1  Compliance by performance on an individual component 
basis. Each component of the building envelope shall meet the 
provisions of table 502.1a as provided in sections 502.2.1.1--
502.2.1.6.
    502.2.1.1  Walls.
    502.2.1.1.1  Conventional framing. The combined thermal 
transmittance value (UO) of the gross area of exterior walls 
shall not exceed the value given in table 502.1a. Equation 502.2a shall 
be used to determine acceptable combinations to meet this requirement.

[[Page 24187]]

[GRAPHIC] [TIFF OMITTED] TP02MY97.000


where:

Uo=the average thermal transmittance of the gross area of 
exterior walls.
Ao=the gross area of exterior walls.
Uw=the combined thermal transmittance of the various paths 
of heat transfer through the opaque exterior wall area.
Aw=area of exterior wall that is opaque.
Ug=the thermal transmittance of the area of all windows 
within the gross wall area as determined in accordance with section 
102.3 of this part.
Ag=the area of all windows within the gross wall area.
Ud=the thermal transmittance of the area of all doors within 
the gross wall area as determined in accordance with section 102.3 of 
this part.
Ad=the area of all doors within the gross wall area.
    When more than one type of wall, window, or door is used, the U  x  
A term for that item shall be expanded into sub-elements as:

UwAw = (Uw1Aw1) + 
(Uw2Aw2) + (Uw3Aw3) + ... 
(etc.)

    502.2.1.1.2  Metal framing. When exterior walls are framed with 
metal studs, calculate the value of Uw used in equation 
502.2b as follows:
where:

Rs=the total thermal resistance of the elements, in series 
along the path comprising the wall assembly of heat transfer, excluding 
the cavity insulation and the metal stud.
Rins=the R value of the cavity insulation
Fc=the correction factor listed in Appendix table 
502.2.1.1.2.

[GRAPHIC] [TIFF OMITTED] TP02MY97.001

    502.2.1.1.3  Any vertical glazing assemblies or vertical walls that 
form part of a roof assembly that bounds conditioned space, such as 
clerestories and dormers, shall be treated as part of the exterior wall 
area for purposes of complying with this part.
    502.2.1.2  Roof/ceiling. The combined thermal transmittance value 
(UO) of the gross area of the roof or ceiling assembly shall not exceed 
the value given in table 502.1a. Equation 502.2c shall be used to 
determine acceptable combinations to meet this requirement.

[GRAPHIC] [TIFF OMITTED] TP02MY97.002

where:

Uo=the average thermal transmittance of the gross roof/
ceiling area.
Ao=the gross area of the roof/ceiling assembly.
UR=the thermal transmittance of all elements of the opaque 
roof/ceiling area.
AR=area of the opaque roof/ceiling assembly.
Us=the thermal transmittance of the area of all skylight 
elements in the roof/ceiling assembly as determined in accordance with 
section 102.3 of this part.
As=the area (including frame) of all skylights within the 
roof/ceiling assembly.

    When more than one type of roof/ceiling or skylight is used, the U 
x  A term for that item shall be expanded into its sub-elements, as:

    UR  x  AR = (UR1  x  
AR1) + (UR2  x  AR2) + ...etc.

    502.2.1.2.1  When return air ceiling plenums are employed, the 
roof/ceiling assembly shall:
    (a) For thermal transmittance purposes, not include the ceiling 
proper nor the plenum space as part of the assembly and, b) For gross 
area purposes, be based upon the interior face of the upper plenum 
surface.
    502.2.1.3  Floors over unheated spaces. The combined thermal 
transmittance value (UO) of the gross area of floors over 
unheated spaces shall not exceed the value given in table 502.1a. The 
thermal transmittance requirement of this section does not apply to 
floors over unvented crawl spaces and basements if the requirements of 
section 502.2.1.5 and/or 502.2.1.6 are met. For floors over outdoor 
air, e.g., overhangs, the UO value shall meet the same 
requirement shown for roofs in table 502.1a. Equation 502.2d shall be 
used to determine acceptable combinations to meet this requirement.

[GRAPHIC] [TIFF OMITTED] TP02MY97.003

where:
UO=the combined thermal transmittance of the different floor 
assemblies.
AO=the gross area of all floor assemblies.
U1,...,n=the thermal transmittance of the various heat 
transfer paths through the first (or nth) floor assembly.
Af1,...,fn=the area of the first (or nth) floor assembly.

    502.2.1.4  Slab-on-grade floors. For slab-on-grade floors, the 
thermal resistance of the insulation around the perimeter of the floor 
shall not be less than the value given in table 502.1a. Insulation 
shall be placed on the outside

[[Page 24188]]

of the foundation or on the inside of the foundation wall. In climates 
below 3,333 annual Celsius heating degree days (HDD) (6,000 annual 
Fahrenheit HDD), the insulation shall extend downward from the top of 
the slab for a minimum distance of 0.610 m (24 in.) or downward to at 
least the bottom of the slab and then horizontally to the interior or 
exterior for a minimum total distance of 0.610 m (24 in.) and shall be 
designed for ground contact. In climates equal to or greater than 3,333 
annual Celsius heating degree days (HDD) (6,000 annual Fahrenheit HDD), 
the insulation shall extend downward from the top of the slab for a 
minimum of 1.22 m (48 in.) or downward to at least the bottom of the 
slab and then horizontally to the interior or exterior for a minimum 
total distance of 1.22 m (48 in.). In all climates, horizontal 
insulation extending outside of the foundation shall be covered by 
pavement or soil a minimum of 0.254 m (10 in.) thick. If the insulation 
is placed to the inside of the foundation wall, there must be 
insulation placed between the slab and the foundation wall. The top 
edge of the insulation installed between the exterior wall and the edge 
of the interior slab shall be permitted to be cut at a 45 deg. angle 
away from the exterior wall.
    502.2.1.5  Crawl space walls. If the floor above a crawl space does 
not meet the requirements of section 502.2.1.3 and the crawl space does 
not have ventilation openings that communicate directly with outside 
air, then the exterior walls of the crawl space shall have a thermal 
transmittance value not exceeding the value given in table 502.1a. 
Where the inside ground surface is less than 0.305 m (12 in.) below the 
outside finish ground level or the vertical wall insulation stops less 
than 0.305 m (12 in.) below the outside finish ground level, crawl 
space wall insulation shall extend vertically and horizontally a 
minimum total distance of 0.610 m (24 in.) linearly from the outside 
finish ground level (see RS-13).
    502.2.1.6  Basement walls. The exterior walls of basements below 
uninsulated floors shall have a thermal transmittance value not 
exceeding the value given in table 502.1a from the top of the basement 
wall to a depth of 3.05 m (10 ft) below the outside finish ground 
level, or to the level of the basement floor, whichever is less.
    502.2.2  Compliance by whole building performance. The stated 
UO, U, or R value of an assembly may be increased or 
decreased, provided the total heat gain or loss for the entire building 
does not exceed the total resulting from conformance to the values 
specified in table 502.1a.
    502.3  Air leakage.
    502.3.1  Window and door assemblies. Window and door assemblies 
installed in the building envelope shall comply with the maximum 
infiltration rates allowed in RS-15, -16, -17, -18, and -19.
    502.3.1.1  Exception. Site-constructed windows and doors shall be 
sealed in accordance with section 502.3.2.
    502.3.2  Caulking and sealants. Joints, openings, and penetrations 
in the building envelope that are sources of air leakage shall be 
sealed with caulking, gasketing, weather-stripping, house wrap, or 
other materials compatible with the construction materials, location, 
and anticipated conditions. Sealants used in joints between dissimilar 
materials shall allow for differential expansion and contraction of 
such materials.
    502.3.3  Recessed lighting fixtures. When installed in the building 
envelope, recessed lighting fixtures shall meet one of the following 
requirements:
    (a) Type IC rated, manufactured with no penetrations between the 
inside of the recessed fixture and the ceiling cavity, and sealed or 
gasketed to prevent air leakage into the unconditioned space.
    (b) Type IC or non-IC rated, installed inside a sealed box 
constructed from a minimum 0.013-m (\1/2\-in.) thick gypsum wallboard, 
a preformed polymeric vapor barrier, or other air-tight assembly 
manufactured for this purpose. The fixture shall maintain a 0.013-m 
(\1/2\-in.) minimum clearance from combustible material and 0.064 m (3 
in.) minimum clearance from insulation material.
    (c) Type IC rated in accordance with RS-15 with no more than 0.944 
L/s (2.0 cfm) air movement from the conditioned space to the ceiling 
cavity. The fixture shall be tested at 75 Pascals or 1.57 psf pressure 
differential and shall be labeled.


Sec. 435.503  Building mechanical systems and equipment.

    503.1  General. This section covers mechanical systems and 
equipment used to provide heating, ventilating, and air-conditioning 
functions.
    503.2  Mechanical equipment efficiency. Mechanical equipment used 
to provide heating and air-conditioning functions shall be selected 
pursuant to the following:
    503.2.1  Detached one and two family dwellings. Heating and air-
conditioning equipment selection shall comply with section 503.2.1.1 or 
section 503.2.1.2.
    503.2.1.1  Minimum federal standards. The installed equipment type 
shall have the lowest life-cycle cost of all the applicable equipment 
included in table 503.2, when those equipment types have been evaluated 
at the minimum equipment performance efficiency allowed under Federal 
standards as specified in 10 CFR part 430.
    503.2.1.2  Alternative approach. Any equipment that is at least as 
life-cycle cost-effective as the equipment identified in section 
503.2.1.1 may be installed.
    503.2.1.3  When either the selected equipment or the equipment 
identified in table 503.2 to which it is compared provides both heating 
and cooling, the life-cycle cost comparison shall be based on the 
combined life-cycle cost of providing heating and cooling services. 
Otherwise, separate heating and cooling life-cycle cost comparisons 
shall be made.
    503.2.1.4  All such equipment shall be installed in accordance with 
the manufacturer's instructions.

       Table 503.2.--Mechanical Equipment Regulated by Federal Law      
------------------------------------------------------------------------
  Heat pump \1\ or air conditioner;                                     
  air, water or evaporatively cooled      <70,320 kW  (<240,000 Btu/h)  
------------------------------------------------------------------------
Packaged Terminal Air Conditioner or   All Capacities.                  
 Heat Pump.                                                             
Warm Air Furnaces, Gas and Oil-Fired.  All Capacities.                  
Boilers, Gas-and Oil-Fired...........  All Capacities.                  
------------------------------------------------------------------------
\1\ Does not include ground-water source heat pumps.                    

    503.2.2  Central heating and air-conditioning units for multiple 
dwelling units in multi-family low rise dwellings. Heating and air-
conditioning equipment selection shall comply with section 503.2.2.1 or 
section 503.2.2.2.
    503.2.2.1  Equipment covered by RS-20. The installed equipment type 
shall have the lowest life-cycle cost of all the applicable equipment 
included in table 403.1 of RS-20, when those equipment types have been 
evaluated at the minimum equipment performance efficiency allowed by 
table 403.1 of RS-20 for the capacity required.
    503.2.2.2  Alternative approach. Any equipment that is at least as 
life-cycle cost-effective as the equipment identified in section 
503.2.2.1 may be installed.
    503.2.2.3  When either the selected equipment or the equipment 
identified

[[Page 24189]]

in table 403.1 of RS-20 to which it is compared provides both heating 
and cooling, the life-cycle cost comparison shall be based on the 
combined life-cycle cost of providing heating and cooling services. 
Otherwise, separate heating and cooling life-cycle cost comparisons 
shall be made.
    503.2.2.4  All such equipment shall be installed in accordance with 
the manufacturer's instructions.
    503.3  HVAC systems.
    503.3.1  Load calculations. Heating and cooling system design loads 
for the purpose of sizing systems and equipment shall be determined in 
accordance with the procedures described in RS-4, or an equivalent 
computation procedure, using the design parameters specified in section 
302 of this part. Design loads shall account for infiltration.
    503.3.1.1  Heating and cooling equipment capacity.
    503.3.1.2  Heating equipment. The capacity of the equipment shall 
not exceed 170% of the design load.
    503.3.1.3  Exception. Power burner and induced-draft burner fossil 
fuel heating equipment.
    503.3.2  Cooling-only equipment. Equipment capable of providing 
only cooling shall be selected so the sensible capacity of the 
equipment is not less than the calculated total sensible cooling load 
but not more than 125% of the design sensible load or the closest 
available size provided by the manufacturer. The corresponding latent 
capacity of the equipment shall not be less than the calculated latent 
load.
    503.3.3  Heat pump equipment. Heat pump sizing shall be based on 
the cooling design requirements and shall not exceed 125% of the 
cooling load at design conditions. For variable-speed or multiple-speed 
units, the cooling capacity at the lowest speed shall not exceed 125% 
of the cooling load at design conditions. Alternatively, where these 
data are not available for design temperatures, the capacity at the 
design heating temperature may be determined by interpolation or 
extrapolation of manufacturers' performance data. The auxiliary 
electric resistance heat capacity shall not exceed 120% of the design 
heating requirement.
    503.3.4  Central electric furnace. Central electric furnaces shall 
be installed within the conditioned space unless they are specifically 
designed for use outside the conditioned space. Such furnaces greater 
than 12 kW (3.42 tons) shall be divided into at least two stages. An 
electric heat pump or an off-peak electric heating system with thermal 
storage shall be installed in conjunction with the furnace for 
locations with 111 HDD, base 18.3  deg.C (200 HDD, base 65  deg.F) or 
more.
    503.4  Temperature and humidity controls.
    503.4.1  System controls. Each dwelling unit shall be considered a 
zone and be provided with thermostatic controls responding to 
temperature within the dwelling unit. Each heating and cooling system 
shall include at least one temperature control device. Where a dwelling 
unit is served by more than one system, the thermostatic controls of 
each system shall prevent simultaneous operation in different modes.
    503.4.2  Thermostatic control capabilities. Where used to control 
comfort heating, thermostatic controls shall be capable of being set 
locally or remotely by adjustment or selection of sensors down to 12.9 
deg.C (55  deg.F) or lower.
    503.4.2.1  Where used to control comfort cooling, thermostatic 
controls shall be capable of being set locally or remotely by 
adjustment or selection of sensors up to 29.4  deg.C (85  deg.F) or 
higher.
    503.4.2.2  Where used to control both comfort heating and cooling, 
thermostatic controls shall be capable of providing a temperature range 
or deadband of up to 5.6  deg.C (10  deg.F) or more within which the 
supply of heating and cooling energy is shut off or reduced to a 
minimum.
    503.4.2.2.1  Exception. Thermostats that require manual changeover 
between heating and cooling modes.
    503.4.3  Heat pump supplementary heater. The heat pump shall be 
installed with controls to prevent supplementary heater operation when 
the operating load can be met by the heat pump alone. Supplementary 
heater operation is permitted during transient periods, such as start-
ups, following room thermostat set-point advance, and during defrost.
    503.4.4  Humidistat. Humidistats used for comfort purposes shall be 
capable of being set to prevent the use of fossil fuel or electricity 
to reduce relative humidity below 60% when reducing moisture or to 
increase relative humidity above 30% when adding moisture.
    503.5  Distribution system construction and insulation.
    503.5.1  Piping insulation. All HVAC system piping shall be 
thermally insulated in accordance with table 503.5.1a.
    503.5.1.1  Exceptions.
    (a) Factory-installed piping within HVAC equipment tested and rated 
in accordance with section 503.2.
    (b) Piping that conveys fluids which have a design operating 
temperature range between 12.8  deg.C (55  deg.F) and 48.9  deg.C (120 
deg.F).
    (c) When the heat loss and/or heat gain of the piping without 
insulation does not increase the energy requirement of the building.
    (d) When the piping is installed in basements, cellars, or 
unventilated crawl spaces having insulated walls.
    (e) When additional insulation or vapor barriers have been 
specified to prevent condensation.

                                       Table 503.5.1a.--Minimum Pipe Insulation [thickness in meters (inches)] \3\                                      
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                        Pipe sizes \2\                                  
                                                                     -----------------------------------------------------------------------------------
                                           Fluid temperature range,                                 0.032 to                                            
           Piping system types                  deg.C ( deg.F)          Run outs     0.025 m (1      0.051 m      0.064 to      0.127 to     0.203 m (8 
                                                                       0.051 m (2     in.) and     (1.25 to 2   0.102 m (2.5   0.152 m (5     in.) and  
                                                                         in.)\1\        less          in.)        to 4 in.)     to 6 in.)      larger   
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                        
                                                          Heating Systems Steam and Hot Water                                                           
--------------------------------------------------------------------------------------------------------------------------------------------------------
High pressure/ temperature..............  152.2-232.2...............        0.038         0.064         0.064         0.076         0.089         0.089 
                                          (306-450).................         (1.5)         (2.5)         (2.5)           (3)         (3.5)         (3.5)
Medium pressure/ temperature............  121.7-151.7...............        0.038         0.051         0.064         0.064         0.076         0.076 
                                          (251-305).................         (1.5)           (2)         (2.5)         (2.5)           (3)           (3)
 Low pressure/ temperature..............  93.9-121.1................        0.025         0.038         0.038         0.051         0.051         0.051 
                                          (201-250).................           (1)         (1.5)         (1.5)           (2)           (2)           (2)
Low temperature.........................  48.9-93.3.................        0.013         0.025         0.025         0.038         0.038         0.038 

[[Page 24190]]

                                                                                                                                                        
                                          (120-200).................         (0.5)           (1)           (1)         (1.5)         (1.5)         (1.5)
Steam condensate (for feed water).......  Any.......................        0.025         0.025         0.038         0.051         0.051         0.051 
                                          ..........................           (1)           (1)         (1.5)           (2)           (2)           (2)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Cooling Systems                                                                    
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                        
Chilled water...........................  4.4-12.8..................        0.013         0.013         0.019         0.025         0.025         0.025 
                                          (40-55)...................         (0.5)         (0.5)        (0.75)           (1)           (1)           (1)
Refrigerant, or brine...................  Below 4.4.................        0.025         0.025         0.038         0.038         0.038         0.038 
                                          (40)......................           (1)           (1)         (1.5)         (1.5)         (1.5)         (1.5)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Runouts not exceeding 3.66 m (12 ft) in length to individual terminal units.                                                                        
\2\ For piping exposed to outdoor air, increase insulation thickness by 0.0127 m (0.5 in.).                                                             
\3\ Insulation thicknesses are based on insulation having thermal resistivity in the range of 27.7 to 31.9 (m \2\. deg.C)/W per meter [4.0 to 4.6 h.ft  
  \2\. deg.F/Btu per inch] of thickness on a flat surface at a mean temperature of 23.9 deg.C (75 deg.F).                                               

    503.5.1.2  For materials with thermal resistivity greater than 0.81 
(4.6), the minimum insulation thickness may be reduced as determined by 
equation 503.5.1.2a:
[GRAPHIC] [TIFF OMITTED] TP02MY97.004

    503.5.1.3  For materials with thermal resistivity less than 0.71 
(4.0), the minimum insulation thickness shall be increased as 
determined by equation 503.5.1.2b:
[GRAPHIC] [TIFF OMITTED] TP02MY97.005

503.5.2  [RESERVED]


503.5.3  [RESERVED]


503.5.4  [RESERVED]


503.5.5  [RESERVED]

    503.5.6  Duct system insulation. All supply and return air ducts 
and plenums installed as part of an HVAC air distribution system shall 
be insulated to provide a thermal resistance, excluding film 
resistances, to that value determined by equation 503.5.6a:

[GRAPHIC] [TIFF OMITTED] TP02MY97.006

Where t= the design temperature difference between the air in 
the duct and the temperature of the ambient air in contact with the 
exterior duct surface.

    503.5.6.1  Exceptions. Duct insulation, except as required to 
prevent condensation, is not required in the following cases:
    (a) When t is 13.9  deg.C (25  deg.F) or less.
    (b) When supply-or return-air ducts are installed in basements, 
cellars, or unventilated crawl spaces having insulated walls in one-and 
two-family dwellings.
    (c) When the heat gain or loss of the ducts, without insulation, 
will not increase the energy requirements of the building.
    (d) Within HVAC equipment.
    (e) Exhaust air ducts.
    503.5.6.2  For buildings with uninsulated roofs over attics 
containing ducts, the air temperature shown in table 503.5.6.2 shall be 
used.

                  Table 503.5.6.2.--Attic Temperatures                  
------------------------------------------------------------------------
            Seasonal conditions                      Temperature        
------------------------------------------------------------------------
Summer conditions:                                                      
  Roof slope:                                                           
    5 in 12 and up........................  54.4  deg.C (130  deg.F).   
    3 in 12 to 5 in 12....................  60.0  deg.C (140  deg.F).   
    less than 3 in 12.....................  65.6  deg.C (150  deg.F).   
Winter conditions all slopes..............  5.56  deg.C (10  deg.F)     
                                             above outdoor design.      
------------------------------------------------------------------------

    503.5.7  Duct construction. Ductwork shall be constructed and 
erected in accordance with Standards RS-6, RS-21, RS-22, RS-23, or RS-
24 listed in section 801 of this part or in accordance with the 
construction documents.
    503.5.7.1  Duct testing. High-pressure and medium-pressure ducts 
shall be leak tested in accordance with the applicable standards in 
section 801 of this part with the rate of air leakage not to exceed the 
maximum rate specified in that standard.
    503.5.7.2  Duct sealing. All low-pressure supply and return air 
ducts, including those that are created within stud bays or joist 
cavities by covering with sheet metal, shall be sealed using mastic 
with fibrous backing tape installed according to the manufacturer's 
specifications. Other sealants may be specified if their

[[Page 24191]]

performance can be demonstrated to equal or exceed that of mastic with 
fibrous backing tape. For fibrous glass ductwork, pressure-sensitive 
tape may be used if installed in accordance with RS-24. Duct tape is 
not permitted as a sealant on any ducts.
    503.5.8  Mechanical ventilation. Each mechanical ventilation system 
(supply and/or exhaust) shall be equipped with a readily accessible 
switch or other means for shutoff or volume reduction and shutoff when 
ventilation is not required. Automatic or gravity dampers that close 
when the system is not operating shall be provided for outdoor air 
intakes and exhausts.
    503.5.9  Combustion air. Each combustion device shall be properly 
installed and provided with a sufficient air supply to meet the air 
flow requirements for that device. For any fuel-burning equipment 
installed in the dwelling unit, combustion zone depressurization shall 
not exceed the equipment's depressurization limit.
    503.5.9.1  Backdrafting test. Dwelling units that have installed 
combustion appliances requiring a vent pipe or chimney (including gas 
clothes dryers, water heaters, furnaces, fireplaces, and wood stoves) 
shall be tested for depressurization-induced chimney failure 
(backdrafting) in accordance with RS-25. If backdrafting occurs, the 
cause of insufficient make-up air shall be identified and corrected 
before occupancy. Testing is not required if the combustion air is 
supplied directly from the outdoors to the combustion chamber via a 
sealed passageway, and the products of combustion are exhausted 
directly outdoors through an independent sealed vent.
    503.5.9.2  Combustion air supplies. Any duct, pipe, screened 
opening or other construction feature which serves to provide 
combustion air to fossil-fuel burning appliances, including service 
water heaters, shall be prominently labeled in a readily accessible 
location directly on or immediately adjacent to the construction 
feature. The label shall contain the following statement, or words 
conveying a similar intent:

    Warning: This pipe [duct, vent, etc.] has been installed to 
provide combustion air for an appliance that burns natural gas, 
propane gas, fuel oil, or any solid fuel. It should not be modified 
or obstructed in any way, without first consulting a qualified HVAC 
contractor or your local building department. Obstruction or 
improper modification may cause toxic combustion products to be 
drawn into the living space of the home.

    503.5.10  Transport energy. The air transport factor for each all-
air system shall be not less than 5.5 when calculated in accordance 
with equation 503.5.10a. The factor shall be based on design system air 
flow. Energy for transfer of air through heat recovery devices shall 
not be included in determining the factor.
[GRAPHIC] [TIFF OMITTED] TP02MY97.007

    503.5.10.1  For purposes of these calculations, Space Sensible Heat 
Load Removal Rate is equivalent to the maximum coincident design 
sensible cooling load of all spaces served for which the system 
provides cooling. Fan Power Input is the rate of energy delivered to 
the fan prime mover.
    503.5.10.2  Air and water, all-water and unitary systems employing 
chilled, hot, dual-temperature or condenser water-transport systems to 
space terminals shall not require greater transport energy (including 
central and terminal fan power and pump power) than an equivalent all-
air system providing the same space sensible heat removal and having an 
air transport factor not less than 5.5.
    503.5.11  Balancing. The HVAC system design shall provide means for 
balancing air and water systems. Components for balancing include 
dampers, temperature and pressure test connections, and balancing 
valves.


Sec. 435.504  Service water heating.

    504.1  General. The purpose of this section is to provide criteria 
for design and equipment selection that will produce energy savings 
when applied to service water heating. Water supplies to ice-making 
machines and refrigerators shall be taken from a cold-water line of the 
water distribution system.
    504.2  Performance efficiency. Mechanical equipment used to provide 
residential service water heating functions shall be selected pursuant 
to the following:
    504.2.1  Detached one and two family dwellings. Service water 
heating equipment selection shall comply with section 504.2.1.1 or 
section 504.2.1.2.
    504.2.1.1  Minimum federal standards. The installed equipment type 
shall have the lowest life-cycle cost of all the applicable equipment 
included in section 430.32(d) of 10 CFR part 430, Subpart C, when those 
equipment types have been evaluated at the minimum equipment 
performance efficiency allowed under Federal standards as specified in 
10 CFR part 430.
    504.2.1.2  Alternative approach. Any equipment that is at least as 
life-cycle cost-effective as the equipment identified in section 
504.2.1.1 may be installed.
    504.2.1.3  When either the selected equipment or the equipment 
identified in section 403.32(d) of 10 CFR part 430, Subpart C to which 
it is compared provides heating or cooling to the conditioned space of 
the building, in addition to service water heating, the life-cycle cost 
comparison shall be based on the combined life-cycle cost of providing 
service water heating and the heating or cooling service. Otherwise, 
separate life-cycle cost comparisons shall be made.
    504.2.1.4  All such equipment shall be installed in accordance with 
the manufacturer's instructions.
    504.2.2  Service water heating units for multiple dwelling units in 
multi-family low rise dwellings. Service water heating equipment 
selection shall comply with section 504.2.2.1 or section 504.2.2.2.
    504.2.2.1  Equipment covered by RS-20. The installed equipment type 
shall have the lowest life-cycle cost of all the applicable equipment 
included in table 404.1 of RS-20, when those equipment types have been 
evaluated at the minimum equipment performance efficiency allowed by 
table 404.1 of RS-20.
    504.2.2.2  Alternative approach. Any equipment that is at least as 
life-cycle cost-effective as the equipment identified in section 
504.2.2.1 may be installed.
    504.2.2.3  When either the selected equipment or the equipment 
identified in table 404.1 of RS-20 to which it is compared provides 
heating or cooling to the conditioned space of the building, in 
addition to service water heating, the life-cycle cost comparison shall 
be based on the combined life-cycle cost of providing service water 
heating and heating or cooling service. Otherwise,

[[Page 24192]]

separate life-cycle cost comparisons shall be made.
    504.2.2.4  All such equipment shall be installed in accordance with 
the manufacturer's instructions.
    504.3  Combination service water heating and space heating 
equipment. Equipment shall not be used to serve both space heating and 
service water heating unless: the annual space heating energy is less 
than 50% of the annual service water heating energy; the energy input 
or storage volume of the combined space heating equipment and water 
heater is less than twice the energy input or storage volume of the 
smaller of the separate space heating equipment or water heaters 
otherwise required; or the input to the combined equipment is less than 
43.95 kW (150,000 Btu/h).
    504.4  Heat traps. Water heaters with vertical pipe risers shall 
have a heat trap installed on both the inlet and outlet of the water 
heater unless the water heater has an integral heat trap or is part of 
a circulating system.
    504.5  Automatic controls. Service water-heating systems shall be 
equipped with automatic temperature controls capable of maintaining a 
pre-selected temperature. The control shall be preselected to a 
temperature of 60  deg.C (140  deg.F) or less.
    504.6  Shutdown. A separate switch shall be provided to permit 
turning off the energy supplied to electric service water-heating 
systems. A separate valve shall be provided to permit turning off the 
energy supplied to the main burner(s) of all other types of service 
water-heating systems.
    504.7  Pump operation. Circulating hot-water systems shall be 
arranged so that the circulation pump(s) can be conveniently turned 
off, automatically or manually, when the hot-water heater is not in 
operation.
    504.8  Pipe insulation. For recirculating systems, piping heat loss 
shall be limited to a maximum of 5.13 W (17.5 Btu/h) per linear foot of 
pipe by insulating in accordance with table 504.8a. Table 504.8a is 
based on a design temperature external to the system piping of 18.3 
deg.C (65  deg.F) minimum. Lower design temperatures shall require 
recalculation of the required piping insulation to limit heat loss to 
the above amount.
    504.8.1  Exception. Piping insulation is not required when the heat 
loss of the piping, without insulation, does not increase the annual 
energy requirements of the building.

                                   Table 504.8a.--Minimum Pipe Insulation \2\                                   
                                         [Thickness in meters (inches)]                                         
----------------------------------------------------------------------------------------------------------------
                                                                          Pipe sizes \1\                        
                                                 ---------------------------------------------------------------
                                                  Noncirculating           Circulating mains and runouts        
  Service water heating  temperatures  deg.C (        runouts    -----------------------------------------------
                     deg.F)                      ----------------                                               
                                                   Up to 0.025 m   Up to 0.032 m   0.038-0.051 m   Over 0.051 m 
                                                      (1 in.)       (1.25 in.)      (1.5-2 in.)       (2 in.)   
----------------------------------------------------------------------------------------------------------------
76.7-82.2 (170-180).............................     0.013 (0.5)     0.025 (1.0)     0.038 (1.5)     0.051 (2.0)
60.0-71.1 (140-160).............................     0.013 (0.5)     0.013 (0.5)     0.025 (1.0)     0.038 (1.5)
37.8-54.4 (100-130).............................     0.013 (0.5)     0.013 (0.5)     0.013 (0.5)    0.025 (1.0) 
----------------------------------------------------------------------------------------------------------------
\1\ Nominal iron pipe size and insulation thickness.                                                            
\2\ See footnote 3 from table 503.5.1a.                                                                         

Sec. 435.505  Electrical power and lighting.

    505.1  Electrical energy consumption. Each separate dwelling unit 
of multifamily residential buildings shall be individually metered.
    505.1.1  Exception. Transient facilities such as dormitories and 
bachelors' quarters are exempt from the requirements of section 505.1.
    505.2  Lighting power budget. The lighting system of the non-
dwelling portion of multi-family residences, such as common stairwells 
and corridors, shall meet the applicable lighting provisions of RS-20.

Subpart F--[Reserved]

Subpart G--Radon Control


Sec. 435.701  General.

    This subpart provides minimum requirements for the control of radon 
from the ground and from construction materials associated with 
buildings. This subpart does not provide requirements for the control 
of radon from ground water or drinking water.


Sec. 435.702  Scope.

    702.1  Building types. These radon control provisions apply to new 
Federal residential buildings, additions to the foundations of such 
buildings, and renovations to such buildings where the foundation wall 
will be exposed.
    702.1.2  Exception. Three story multifamily residential buildings 
that have dwelling units only on the third floor are exempt from the 
requirements of this subpart.
    702.2  Building locations. This subpart applies to any new 
construction located completely or partially in Zone 1 on the U.S. Map 
of Radon Zones as specified in Appendix table 702.2. This subpart shall 
also apply when locally available data, or a radon potential map 
derived from non-local data, indicate a particular site may have a 
radon potential commensurate with that in Zone 1, although not listed 
in Appendix table 702.2 as being in Zone 1.
    702.2.1  Exception. Where measured data collected at or near to the 
proposed construction site, or a radon potential map derived from non-
local data, indicate the construction site does not have a radon 
potential commensurate with that in Zone 1, the provisions of this 
subpart shall not apply.


Sec. 435.703  Compliance.

    703.1  General. Buildings located in areas classified as Zone 1 as 
defined in section 702.2 shall comply with the design and construction 
requirements provided in section 707.
    703.2  Long-term testing. Starting within 30 days after occupancy, 
the building shall be tested for an integration period no less than six 
months in accordance with RS-26. If the radon level is at or above 4 
pCi/L, the radon ventilation system shall be activated in accordance 
with RS-27 within one month of the completion of testing.
    703.3  Short-term testing. Short-term testing shall be performed 
and concluded within 30 days of occupancy for an integration period no 
less than 7 days in accordance with RS-26. If the radon level is at or 
above 20 pCi/L, a second short-term test shall be performed for a 
minimum of 7 days beginning at the conclusion of the first short-term 
test. If the average of the two

[[Page 24193]]

tests exceeds 20 pCi/L, the radon ventilation system shall be 
activated.
    703.4  Follow-up testing.
    703.4.1  Radon testing; short-term. If the ventilation system has 
been activated in response to long-term or short-term testing, 
additional radon testing shall be completed within 10 days of system 
activation for a minimum integration period of two days. If the test 
results exceed 4 pCi/L, additional radon mitigation measures shall be 
performed. After mitigation, any further testing shall be performed.
    703.4.2  Radon testing; long-term. If the results of short-term 
testing performed under section 703.4.1 are 4 pCi/L or less, the long-
term testing required under section 703.2 shall be re-initiated upon 
conclusion of the short-term test for an integration period no less 
than 6 months. If the test results exceed 4 pCi/l, additional radon 
mitigation shall be performed. After mitigation, any further testing 
shall be performed.
    703.4.3  Backdrafting testing. If the ventilation system has been 
activated in response to long-term or short-term testing, additional 
backdrafting testing shall be performed, in accordance with the 
provisions of section 503.5.9.1, within 30 days of system activation.
    703.5  Reporting of test results. All radon test results shall be 
reported to the Deputy Assistant Secretary for Building Technologies 
(EE-40) at the U.S. Department of Energy, Washington, DC 20585.
    703.6  Ventilation fan alarm. If the radon ventilation fan has been 
activated in response to testing under this section, a visual 
indication of fan operation, or an alarm indicating fan failure, shall 
be installed within the living space of the dwelling unit.


Sec. 435.704  Alternative systems.

    The requirements of this subpart are not intended to preempt, 
preclude, or restrict the application or use of alternative materials, 
systems, or construction practices. Alternative materials, systems, or 
methods of construction shall be acceptable when they can be shown to 
yield radon control equivalent to that required herein. To be 
considered equivalent, a radon level below 4 pCi/L shall be 
demonstrated through long-term testing conducted on a similar building 
(design with similar environmental conditions and operational 
schedules) located in the same radon potential zone, using the proposed 
alternative approaches. Any alternative system is still subject to the 
testing and reporting requirements of section 703.


Sec. 435.705  Conflict with other standards, codes, or regulations.

    The provisions of this subpart are not intended to conflict with 
other health and safety provisions of any other applicable standards, 
codes, or regulations. When a conflict occurs, the requirement with the 
greater positive impact on the health and safety of the building 
occupants shall prevail.


Sec. 435.706  Qualification of testers and installers.

    Active radon control systems shall be designed and installed by 
individuals who are state-certified as radon mitigation contractors or 
by an individual listed in the EPA Radon Contractor Proficiency 
Program. All radon testing shall be performed or supervised by 
individuals who are state-certified as radon measurement contractors or 
are listed in the EPA Radon Contractor Proficiency Program.


Sec. 435.707  Design and construction requirements.

    707.1  Slab-on-grade foundations and slab-below-grade floor 
assemblies.
    707.1.1  Subfloor preparation. A 0.089 m (4-in.) thick layer of 
clean graded sand overlain by a continuous layer or strips of 
geotextile drainage matting designed to allow the lateral flow of soil 
gas, or clean aggregate passing through a 0.051-m (2-in.) sieve and 
retained on a 6.4 mm (\1/4\-in.) sieve, shall be placed under all 
concrete slabs and other floor systems (such as treated-wood floors on 
ground) that directly contact the ground and are within the walls of 
the living spaces of the building.
    707.1.2  Sub-slab membrane.
    707.1.2.1  Application. A 6-mil (or 3-mil cross-laminated) 
polyethylene or equivalent flexible sheeting material shall be placed 
on top of the subfloor prior to casting the slab or placing the floor 
assembly. The sheeting shall cover the entire floor area with separate 
sections of sheeting overlapped at least 0.305 m (12 in.). The sheeting 
shall extend to within 13 mm (\1/2\ in.) of all pipes, wires, or other 
penetrations of the material.
    707.1.2.2  Sealing. All seams, lap joints, penetrations, punctures, 
tears, and other disturbances of the continuity of the sub-slab 
membrane shall be sealed with mastic or tape compatible with the 
membrane material. Paper or cloth tape shall not be used. Where 
additional pieces of membrane material are used for sealing, the piece 
shall overlap the discontinuity a minimum of 12 inches on all sides and 
shall be sealed with mastic or tape.
    707.1.3  Concrete floor slabs. Concrete floor slabs shall be 
designed, mixed, placed, reinforced, consolidated, finished, and cured 
in accordance with RS-28.
    707.1.3.1  Stakes. The use of grade or support stakes which 
penetrate the subslab membrane shall be avoided. Permanent and/or 
temporary concrete blocks or screed chairs may be used. Where stakes 
are used to support plumbing pipes, electrical conduits, or other 
objects which penetrate the slab, they shall be sealed to the slab in 
accordance with section 707.1.4. These stakes shall be solid or have 
the upper end sealed tightly by installation of an end cap designed to 
provide a gas-tight seal. Support stakes shall be of non-porous 
material resistant to decay, corrosion and rust.
    707.1.4 Sealing of floor slabs.
    707.1.4.1 Openings. Openings through concrete slabs, wood, or other 
floor assemblies which provide a direct path to exposed soil (such as 
spaces around bathtub, shower, or toilet drains) shall be filled or 
closed with non-shrink mortar, grout, expanding foam, polyurethane 
caulk, elastomeric sealant, or other similar material designed for such 
application that adheres to the surrounding material and remains 
flexible. Where large work spaces are formed into a slab, such as 
beneath a bath tub drain, the exposed soil shall be fully covered with 
a solvent-based plastic roof cement or other material, to a minimum 
depth of 1 inch.
    707.1.4.2 Penetrations. Gaps around pipe, wire, or other objects 
that penetrate concrete slabs, wood, or other floor assemblies shall be 
made airtight with an elastomeric joint sealant as defined in RS-29 and 
applied in accordance with RS-30 and the sealant manufacturer's 
installation instructions.
    707.1.4.3 Joints. All control joints, isolation joints, 
construction joints, and other joints in concrete slabs or between 
slabs and foundation walls shall be sealed. A continuous formed gap 
(for example, a ``tooled edge''), which allows for the application of a 
sealant that will provide a continuous, airtight seal, shall be created 
along all joints. When the slab has cured, the gap shall be cleared of 
loose material and filled with an elastomeric joint sealant as 
described in section 707.1.4.2.
    707.1.4.4 Cracks. Cracks in the field of a slab with widths greater 
than 1.59 mm (\1/16\ in.) shall be routed to a recess with minimum 
dimensions of 6.35 mm (\1/4\ in.) by 6.35 mm (\1/4\ in.) and sealed 
with an approved sealant.
    707.1.5 Foundation walls.
    707.1.5.1 Concrete and masonry. Below-grade concrete and masonry 
foundation walls shall be water-proofed. Where basements are 
constructed with

[[Page 24194]]

hollow block masonry, the exterior walls shall be covered with 6-mil 
minimum polyethylene sheeting, extending from the finished grade to 
cover the joint with the footing. Hollow block masonry walls shall be 
constructed with one continuous course of solid masonry, masonry that 
is grouted solid, or a solid concrete beam; the continuous course shall 
be located at or above finished grade. Where a brick veneer or other 
masonry ledge is installed, the course immediately below that ledge 
shall be sealed in the same manner.
    707.1.5.2 Wood. Pressure-treated wood foundations shall be 
constructed, installed, and water-proofed in accordance with RS-31.
    707.1.5.3 Joints and penetrations. Joints, cracks, or other 
openings around all below-grade penetrations or wall ties shall be 
sealed airtight with an elastomeric sealant on both the inside and 
outside surfaces of the foundation wall.
    707.2 Crawl spaces.
    707.2.1 Openings. Openings around all penetrations of those 
building assemblies that separate crawl spaces from habitable space 
shall be sealed to prevent air leakage. Means of egress and ingress 
between habitable spaces and crawl spaces, such as hatches or access 
doors, shall be sealed or gasketed to prevent air leakage.
    707.2.2 Ventilation. Crawl spaces shall be provided with at least 
0.0929 m\2\ (1 ft\2\) net free area of ventilation openings for each 
27.9 m\2\ (300 ft\2\) of crawl space area. Such vents shall be through 
the exterior wall and be of noncloseable design.
    707.2.3  Ground cover. The soil in crawl spaces shall be cleaned of 
all vegetation and organic matter and covered with a continuous layer 
of 6-mil thick polyethylene sheeting or an equivalent membrane 
material. The sheeting shall be lapped at least 0.305 m (12 in.) at 
joints. All seams, joints, penetrations, punctures, and tears in the 
ground cover membrane shall be sealed in accordance with section 
707.1.2.2. The membrane shall fully cover the floor and abut to the 
foundation walls or footings.
    707.3  Vent system.
    707.3.1  Passive sub-membrane depressurization system for crawl 
space construction. One continuous, uninterrupted vent pipe, sealed 
permanently gas-tight at joints, at least 0.064 m (3 in.) in diameter, 
and meeting the provisions of RS-32 or RS-33 shall be provided to vent 
the soil in the crawl space. The vent pipe shall be connected to a 
plumbing ``T'' fitting and inserted between the membrane and the soil 
such that the ``T'' fitting rests on the ground and its openings are 
completely below the membrane. A minimum of five feet of perforated 
drain pipe of three inches minimum diameter shall join to and extend 
from each opening of the ``T.'' The pipe perforations shall be parallel 
to the plane of the ground and shall not be capped at the ends. The 
``T'' and its perforated extensions shall be located at least 1.52 m (5 
ft) and no more than 5.49 m (18 ft) (measured in a horizontal plane) 
from the exterior perimeter of the crawlspace area. The vent pipe shall 
terminate above the roof as required in section 707.3.4. The vent pipe 
shall have a maximum of 3 elbow or tee fittings between the sub-
membrane fitting and the roof termination.
    707.3.2  Passive sub-slab depressurization system for basement 
floor and slab-on-grade foundation construction. A minimum of one 
continuous, uninterrupted vent pipe, sealed permanently gas-tight at 
joints, at least 0.64 m (3 in.) in diameter, and meeting the provisions 
of RS-32 or RS-33 shall be provided to vent the soil below the floor 
slab. The vent pipe shall have a plumbing ``T'' fitting of the same 
diameter at one end that shall be placed into the subslab aggregate or 
other permeable material before the slab is poured. The ``T'' fitting 
openings shall be completely below the sub-slab membrane. Each subslab 
termination of the vent pipe shall serve no more than 232 m\2\ (2500 ft 
\2\) of slab floor area. The ``T'' fittings shall be located at least 
five feet and no more than 5.49 m (18 ft) (measured in a horizontal 
plane) from the exterior perimeter of the foundation. The pipe shall 
terminate above the roof as required in section 707.3.4. The vent pipe 
shall have a maximum of 3 elbow or tee fittings between the sub-slab 
fitting and the roof termination.
    707.3.2.1  Multiple suction points. Where a single residence has 
multiple floor slabs, floor slabs in excess of 232 m\2\ (2500 ft \2\), 
or floor slabs that are provided and separated by interior footings or 
other barriers to the lateral flow of subslab soil gas, additional vent 
pipes shall be installed to ensure that all subslab areas are 
ventilated. Such pipes shall run independently and terminate as 
required in section 707.3.4 or shall be manifolded in an accessible 
location and connected to a single vent terminating above the roof as 
required in section 707.3.4. Each vent pipe, even if manifolded, shall 
have a maximum of 3 elbow or tee fittings between the sub-slab fitting 
and the corresponding roof termination.
    707.3.2.2  Exceptions. A sealed slab sump exposed to the sub-slab 
aggregate, or internal drain tile loops that are stubbed up through the 
slab, either of which is in turn connected to a vent pipe extending 
vertically and terminating above the roof as required in section 
707.3.4, are exempt from the requirements of section 707.3.2.
    707.3.3  Combination construction. In combination basement/crawl 
space or slab-on-grade/crawl space construction, the vent systems 
required by sections 707.3.1 or 707.3.2 shall be separate systems or 
manifolded in an accessible location and connected to a single vent 
terminating above the roof as required in section 707.3.4.
    707.3.4  Vent pipe termination. The vent pipe shall run through the 
conditioned part of the house to the greatest extent possible and shall 
not be located within an external wall. A portion of the vent pipe 
shall be accessible in the attic or other area outside of the habitable 
space. The vent pipe shall be labeled ``RADON REDUCTION SYSTEM'' in 
0.051-m (2-in.) high black letters on a yellow band on each floor level 
where the vent pipe(s) is exposed and visible. The vent pipe shall be 
installed with a minimum slope of 3.18 mm (\1/8\-in.) per 0.305 m (ft) 
to drain rainwater or condensate by gravity to the soil. The vent pipe 
shall terminate in a vertical section that extends at least 0.305 m (12 
in.) above the surface of the roof. The termination point shall be at 
least 3.05 m (10 ft) away from any window or other opening into the 
building's conditioned space that is less than 0.610 m (2 ft) below the 
termination point. The termination point shall be at least 3.05 m (10 
ft) from any adjoining or adjacent buildings.
    707.3.5  Electrical service. An approved electrical junction box 
rated for a 20 amp feed to an external device shall be installed within 
20 feet of that portion of the vent pipe in the attic or other area 
outside of the habitable space identified in section 707.3.4.
    707.4  Plumbing system interconnections.
    707.4.1  Drains. Floor drains shall be trapped and connected to the 
building's sanitary drain system. Condensate drains serving cooling 
coils shall terminate outside the building to daylight or to a floor 
drain, plumbing fixture, sump, or other approved location.
    707.4.2  Sumps. Sumps open to soil or serving as the termination 
point for subslab or exterior drain tile loops shall be tightly 
covered. When serving as a floor drain, the sump lid shall be equipped 
with a trapped inlet.
    707.5  HVAC system interconnections.

[[Page 24195]]

    707.5.1  Air-handling units. Air-handling units shall not be 
located in crawl spaces or other areas exposed to soil gas.
    707.5.1.1  Exception. When the air-handler is sealed so as to 
preclude the circulation of air from the area exposed to soil gas.
    707.5.2  Ducts. Air-handling ducts exposed to soil gas shall be 
made permanently airtight by sealing in accordance with section 
503.5.7. Ducts shall not be installed beneath slabs.
    707.5.3  Plenums. Air circulation plenums shall not be located in 
crawl spaces or in other construction assemblies directly exposed to 
soil gas. Any plenum assembly shall be made permanently airtight by 
sealing in accordance with section 503.5.7.

Subpart H--Standards


Sec. 435.801  Reference standards.

    801.1  The standards, and portions thereof, which are referred to 
in various sections, paragraphs, and subparagraphs of this part shall 
be considered a part of this part.

------------------------------------------------------------------------
   Code standard No.                     Title and source               
------------------------------------------------------------------------
RS-1...................  National Fenestration Rating Council 100-91,   
                          Procedure for Determining Fenestration Product
                          Thermal Properties, National Fenestration     
                          Rating Council, 1300 Spring St., Suite 120,   
                          Silver Spring, MD 20910.                      
RS-2...................  ANSI/ASHRAE 55-1992, Thermal Environmental     
                          Conditions for Human Occupancy, American      
                          Society of Heating, Refrigerating, and Air-   
                          Conditioning Engineers Inc. 1791 Tullie       
                          Circle, N.E., Atlanta, GA 30329-2305.         
RS-3...................  ANSI/ASHRAE Standard 62-1989, Ventilation for  
                          Acceptable Indoor Air Quality, American       
                          Society of Heating, Refrigerating, and Air-   
                          Conditioning Engineers, Inc. 1791 Tullie      
                          Circle, N.E., Atlanta, GA 30329-2305.         
RS-4...................  1993 ASHRAE Handbook of Fundamentals, American 
                          Society of Heating, Refrigerating, and Air-   
                          Conditioning Engineers, Inc., 1791 Tullie     
                          Circle, N.E., Atlanta, GA 3 0329-2305.        
RS-5...................  ASTM E 779-87, Standard Test Method for        
                          Determining Air Leakage Rate by Fan           
                          Pressurization, American Society for Testing  
                          and Materials, 1916 Race Street, Philadelphia,
                          PA 19103.                                     
RS-6...................  1992 ASHRAE HVAC Systems and Equipment         
                          Handbook, American Society of Heating,        
                          Refrigerating, and Air-Conditioning Engineers,
                          Inc., 1791 Tullie Circle, N.E., Atlanta, GA   
                          30329-2305.                                   
RS-7...................  ASHRAE, Energy Calculations I: Procedures for  
                          Determining Heating and Cooling Loads for     
                          Computerizing Energy Calculations, Algorithms 
                          for Building Heat Transfer Subsystems, 1975,  
                          American Society of Heating, Refrigerating,   
                          and Air-Conditioning Engineers, Inc., 1791    
                          Tullie Circle, N.E., Atlanta, GA 30329-2305.  
RS-8...................  BuilderGuide Energy Analysis Software for      
                          Homebuilders, Passive Solar Industries        
                          Council, Passive Solar Industries Council,    
                          1511 K. Street N.W., Suite 600, Washington, DC
                          20005.                                        
RS-9...................  ASTM C 177-85, Standard Test Method for Steady-
                          State Heat Flux Measurements and Thermal      
                          Transmission Properties by Means of the       
                          Guarded-Hot-Plate Apparatus, American Society 
                          for Testing and Materials, 1916 Race Street,  
                          Philadelphia, PA 19103.                       
RS-10..................  ASTM C 518-91, Standard Test Method for Steady-
                          State Heat Flux Measurements and Thermal      
                          Transmission Properties by Means of the Heat  
                          Flow Meter Apparatus, American Society for    
                          Testing and Materials, 1916 Race Street,      
                          Philadelphia, PA 19103.                       
RS-11..................  ASTM C 236-89, Standard Test Method for Steady-
                          State Thermal Performance of Building         
                          Assemblies by Means of a Guarded-Hot-Box,     
                          American Society for Testing and Materials,   
                          1916 Race Street, Philadelphia, PA 19103.     
RS-12..................  ASTM C 976-90, Standard Test Method for Thermal
                          Performance of Building Assemblies by Means of
                          a Calibrated Hot Box, American Society for    
                          Testing and Materials, 1916 Race Street,      
                          Philadelphia, PA 19103.                       
RS-13..................  1988 Builder's Foundation Handbook. U.S.       
                          Department of Energy, Office of Scientific and
                          Technical Information, P.O. Box 62, Oak Ridge 
                          TN 37831-9939.                                
RS-14..................  ASTM E 96-94, Standard Test Methods for Water  
                          Vapor Transmission of Materials, American     
                          Society for Testing and Materials, 1916 Race  
                          Street, Philadelphia, PA 19103.               
RS-15..................  ASTM E 283-91, Standard Test Method for        
                          Determining the Rate of Air Leakage Through   
                          Exterior Windows, Curtain Walls and Doors     
                          Under Specified Pressure Differences Across   
                          the Specimen, American Society for Testing and
                          Materials, 1916 Race Street, Philadelphia, PA 
                          19103.                                        
RS-16..................  ANSI/NWWDA I.S.2-87, Industry Standard for Wood
                          Window Units, National Wood Window and Door   
                          Association, 1400 Touhy Ave., Des Plaines, IL 
                          60018.                                        
RS-17..................  ANSI/AAMA 101-93, Voluntary Specifications for 
                          Aluminum and Poly (Vinyl Chloride) (PVC) Prime
                          Windows and Glass Doors, American             
                          Architectural Manufacturers Association, Des  
                          Plaines, IL 60018.                            
RS-18..................  ASTM D 4099-93, Standard Specification for PVC 
                          Prime Windows/Sliding Glass Doors, American   
                          Society for Testing and Materials 1916 Race   
                          Street, Philadelphia, PA 19103.               
RS-19..................  NWWDA I.S.3-88, Industry Standard for Wood     
                          Sliding Patio Doors, National Wood Window and 
                          Door Association, 1400 Touhy Ave., Des        
                          Plaines, IL 60018.                            
RS-20..................  Energy Code for Commercial and High-Rise       
                          Residential Buildings--Codification of ASHRAE/
                          IESNA 90.1-1989, Energy Efficient Design of   
                          New Buildings Except Low-Rise Residential     
                          Buildings, American Society of Heating,       
                          Refrigerating, and Air-Conditioning Engineers,
                          Inc., 1791 Tullie Circle, N.E., Atlanta, GA   
                          30329-2305.                                   
RS-21..................  SMACNA, Installation Standards for Residential 
                          Heating and Air Conditioning Systems, Sixth   
                          Edition, 1988, Sheet Metal and Air            
                          Conditioning Contractors Nat'l Assoc., 4201   
                          Lafayette Center, Dr., Chantilly, VA 22021-   
                          1209.                                         
RS-22..................  SMACNA, HVAC Duct Construction Standards--Metal
                          and Flexible, First Edition, 1985, Sheet Metal
                          and Air Conditioning Contractors Nat'l Assoc.,
                          4201 Lafayette Center, Dr., Chantilly, VA     
                          22021-1209.                                   
RS-23..................  SMACNA Fibrous Glass Duct Construction         
                          Standards, 6th Edition, Washington, D.C.,     
                          1992, Sheet Metal and Air Conditioning        
                          Contractors Nat'l Assoc. 4201 Lafayette       
                          Center, Dr., Chantilly, VA 22021-1209.        
RS-24..................  NAIMA Fibrous Glass Duct Construction          
                          Standards, 1989 Edition, North American       
                          Insulation Manufacturers Assoc., 44 Canal     
                          Center Plaza, Suite 310, Alexandria, VA 22314.
RS-25..................  CGSB, The Spillage Test. CAN/CGSB-51.71-94,    
                          Canadian General Standards Board, 222 Queen   
                          Street, Suite 1402, Ottawa, Ontario, Canada   
                          K1A 1G6.                                      
RS-26..................  EPA 402-R-92-003, Protocol for Radon & Radon   
                          Decay Product Measurements in Homes, United   
                          States Environmental Protection Agency,       
                          Washington, DC 20460.                         
RS-27..................  EPA 402-R-93-078, Radon Mitigation Standards,  
                          United States Environmental Protection Agency,
                          Washington, DC 20460.                         
RS-28..................  ACI Standard 302.1R-89, Guide for Concrete     
                          Floor and Slab Construction, American Concrete
                          Institute, P.O. Box 19150, Redford Station,   
                          Detroit, MI 48219.                            

[[Page 24196]]

                                                                        
RS-29..................  ASTM C 920-94, Standard Specification for      
                          Elastomeric Joint Sealant, American Society   
                          for Testing and Materials, 1916 Race Street,  
                          Philadelphia, PA 19103.                       
RS-30..................  ASTM C 1193-91, Standard Guide for Use of Joint
                          Sealants, American Society for Testing and    
                          Materials, 1916 Race Street, Philadelphia, PA 
                          19103.                                        
RS-31..................  Permanent Wood Foundation Design and           
                          Construction Guide, Southern Pine Council,    
                          Southern Pine Council, P.O. Box 641700,       
                          Kenner, LA 70064.                             
RS-32..................  ASTM D 2665-94, Standard Specification for PVC 
                          Plastic Drain, Waste, and Vent Pipe and       
                          Fittings, American Society for Testing and    
                          Materials, 1916 Race Street, Philadelphia, PA 
                          19103.                                        
RS-33..................  ASTM D 2661-94A, Standard Specification for ABS
                          Plastic Drain, waste, and Vent Pipe and       
                          Fittings, American Society for Testing and    
                          Materials, 1916 Race Street, Philadelphia, PA 
                          19103.                                        
RS-34..................  Analysis of Options for EPA's Model Standards  
                          for Controlling Radon in New Homes, United    
                          States Environmental Protection Agency,       
                          Washington, DC 20460.                         
------------------------------------------------------------------------

Sec. 435.802  Abbreviations and acronyms used in reference standards.

AAMA  American Architectural Manufacturers Association
ACI  American Concrete Institute
ACCA  Air Conditioning Contractors of America
ANSI  American National Standards Institute, Inc.
ARI  Air Conditioning and Refrigeration Institute
ASHRAE  American Society of Heating, Refrigerating, and Air-
Conditioning Engineers, Inc.
ASTM  American Society for Testing and Materials
CABO  Council of American Building Officials
CGSB  Canadian General Standards Board
OSTI  U.S. Department of Energy
EPA  United States Environmental Protection Agency
NWWDA  National Wood Window and Door Association
NAIMA  North American Insulation Manufacturers Assoc.
NFRC  National Fenestration Ratings Council
PSIC  Passive Solar Industries Council
SMACNA  Sheet Metal and Air Conditioning Contractors Nat'l Assoc.
SPC  Southern Pine Council

BILLING CODE 6450-01-P

[[Page 24197]]

Appendix to Part 435--Figures and Tables
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[FR Doc. 97-10922 Filed 4-29-97; 8:45 am]
BILLING CODE 6450-01-C