[Federal Register Volume 69, Number 243 (Monday, December 20, 2004)]
[Rules and Regulations]
[Pages 76298-76337]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-27088]



[[Page 76297]]

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Part IV





Department of Transportation





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National Highway and Traffic Safety Administration



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49 CFR Part 571



Federal Motor Vehicle Safety Standards; Brake Hoses; Final Rule

  Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / 
Rules and Regulations  

[[Page 76298]]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. NHTSA-2003-14483]
RIN 2127-AH79


Federal Motor Vehicle Safety Standards; Brake Hoses

AGENCY: National Highway Traffic Safety Administration (NHTSA), 
Department of Transportation (DOT).

ACTION: Final rule.

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SUMMARY: This rule updates the Federal motor vehicle safety standard on 
brake hoses to incorporate the substantive specifications of several 
Society of Automotive Engineers (SAE) Recommended Practices relating to 
hydraulic brake hoses, vacuum brake hoses, air brake hoses, plastic air 
brake tubing, and end fittings. The agency initiated this rulemaking in 
response to a joint petition from several brake hose and tubing 
manufacturers.

DATES: This final rule becomes effective December 20, 2006. The 
incorporation by reference of certain publications listed in the 
regulations is approved by the Director of the Federal Register as of 
December 20, 2006.
    Optional early compliance is permitted as of February 18, 2005.
    Any petitions for reconsideration of today's final rule must be 
received by NHTSA not later than February 3, 2005.

ADDRESSES: Petitions for reconsideration should refer to the docket 
number for this action and be submitted to: Administrator, National 
Highway Traffic Safety Administration, 400 Seventh Street, SW., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT:
    For non-legal issues, Mr. Jeff Woods, Vehicle Dynamics Division, 
Office of Vehicle Safety Standards (Telephone: (202) 366-6206) (Fax: 
(202) 366-4921).
    For legal issues, Ms. Dorothy Nakama, Office of the Chief Counsel 
(Telephone: (202) 366-2992) (Fax: (202) 366-3820).
    You may send mail to both of these officials at: National Highway 
Traffic Safety Administration, 400 Seventh St., SW., Washington, DC 
20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Background
II. Notice of Proposed Rulemaking
III. Summary of Comments
IV. Agency Decision to Issue a Final Rule
V. Issues Raised by Commenters and NHTSA's Responses
    A. Issues Relating to All Types of Brake Hose
    1. Use of the term ``burst''
    2. Use of the term ``any''
    3. Constriction test method
    4. Specification of ozone concentration
    B. Hydraulic Brake Hoses
    1. General hydraulic brake hose comments in response to the NPRM
    2. Hydraulic brake hose manufacturer identification requirements
    3. Expansion and burst strength (volumetric expansion) test
    4. Tensile strength
    5. Water absorption and pressure test, tensile strength, and 
whip resistance
    6. Low temperature resistance test
    7. Brake fluid compatibility, constriction, and burst strength
    8. End fitting corrosion resistance
    9. High temperature impulse test
    C. Air Brake Hoses
    1. Construction and labeling
    2. High temperature resistance
    3. Low temperature resistance
    4. Ozone resistance
    5. Adhesion
    6. Air pressure (leakage)
    7. Tensile strength
    8. Minimum bend radius
    D. Vacuum Brake Hoses
    1. Swell (fuel resistance)
    E. Plastic Air Brake Tubing
    1. General comments
    2. Construction
    3. Labeling
    4. Dimensions and tolerances
    5. One hundred percent leak test
    6. Burst test
    7. Moisture absorption
    8. Ultraviolet resistance
    9. Resistance to zinc chloride and methyl alcohol
    10. Stiffness
    11. Heat aging adhesion
    12. Collapse resistance
    13. Oil resistance
    14. Ozone resistance
    F. Plastic Air Brake Tubing Assemblies and End Fittings
    1. General comments
    2. Tensile strength
    3. Hot tensile strength
    4. Vibration leak test
    5. Proof and burst test (end fitting retention)
    6. Serviceability test
    7. End fitting dimensional requirements
    8. End fitting corrosion resistance
    G. New Types of Brake Hose
    H. Metallic Tubing and Pipe
    VI. Statutory Bases for the Final Rule
    VII. Effective Date
    VIII. Rulemaking Analyses and Notices
    A. Executive Order 12866 and DOT Regulatory Policies and 
Procedures
    B. Regulatory Flexibility Act
    C. National Environmental Policy Act
    D. Executive Order 13132 (Federalism)
    E. Civil Justice Reform
    F. Paperwork Reduction Act
    G. National Technology Transfer and Advancement Act
    H. Unfunded Mandates Reform Act
    I. Plain Language
    J. Regulation Identifier Number
    Final Rule Regulatory Text

I. Background

    On October 30, 1998, three brake hose manufacturers, Elf Atochem 
North America, Inc., Mark IV Industrial/Dayco Eastman, and Parker 
Hannifin Corporation,\1\ filed a joint petition for rulemaking with 
NHTSA. The petitioners requested that certain requirements relating to 
brake hoses, brake hose tubing, and brake hose end fittings that are 
presently administered by the Federal Motor Carrier Safety 
Administration (FMCSA) be incorporated into the brake hose standard 
that is administered by NHTSA. The Federal Motor Carrier Safety 
Regulations (FMCSR) requirements for brake hoses at 49 CFR 393.45 
(Brake tubing and hose, adequacy) and 49 CFR 393.46 (Brake tubing and 
hose connections) reference several Society of Automotive Engineers 
(SAE) standards that describe the dimensions and performance 
requirements for brake hoses and end fittings for hydraulic, vacuum, 
and air brake hoses, and also metal and plastic tubing and end fittings 
used in brake systems. Specifically, the petitioners requested that the 
SAE standards referenced in the FMCSRs be incorporated into 49 CFR 
571.106 (Brake hoses) of the Federal Motor Vehicle Safety Standards 
(FMVSS) that are administered by NHTSA.
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    \1\ Since the petition was filed, mark IV Industrial/Dayco 
Eastman has been acqired by Parker Hannifin Corporation. Elf Atochem 
North American, Inc. was integrted into Atofina Chemical, Inc. The 
successor petitioning companies are referred to as Parker/Atofina.
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    The petitioners requested that the application of these SAE 
specifications be limited to hose, tubing, and fittings used on trucks, 
truck-trailer combinations, and buses with either a GVWR greater than 
10,000 pounds or which are designed to transport 16 or more people, 
including the driver. In addition, the petitioners requested that the 
current versions of the SAE specifications be adopted instead of the 
older versions cited in the FMCSRs.
    The joint petition was submitted in light of a 1997 proposal by the 
Federal Highway Administration (FHWA), which then administered the 
FMCSRs, to delete these provisions. The FHWA stated that because it has 
no statutory authority to regulate vehicle manufacturers or 
manufacturers of brake hose, tubing, or fittings, all such regulations 
should be included in NHTSA's FMVSS rather than in the FMCSRs. The FHWA 
proposed adopting a requirement that commercial motor vehicles be 
maintained in compliance

[[Page 76299]]

with FMVSS No. 106. However, many of the provisions included in the 
FMCSRs in this subject area were not included in FMVSS No. 106.
    In a 1998 public meeting on the subject, representatives from NHTSA 
and FHWA said that they favored consolidating all requirements for 
brake hose, brake tubing, and fittings in FMVSS No. 106, instead of 
maintaining separate requirements under the jurisdiction of two 
different agencies. They explained that consolidation of the 
requirements would, among other things, make them more enforceable. 
Some of the brake component manufacturers stated their opposition to 
deleting the SAE specifications for their products. FHWA and NHTSA 
indicated that anyone opposed to FHWA's proposal was welcome to file a 
petition for rulemaking requesting that the SAE specifications proposed 
for deletion from the FMCSRs be incorporated into FMVSS No. 106.
    For details about FMCSR's brake hose requirements and additional 
background behind the joint petitions, please see NHTSA's notice of 
proposed rulemaking (NPRM) of May 15, 2003 (68 FR 26384, at pages 26384 
to 26385).

II. Notice of Proposed Rulemaking

    In an NPRM published on May 15, 2003 (68 FR 26384) [DOT Docket No. 
03-14483] NHTSA announced that it had granted the joint petition for 
rulemaking to amend FMVSS No. 106. The agency agreed with the 
petitioners that there was a safety need to transfer the brake hose, 
tubing, and fitting requirements in Sections 393.45 and 393.46 of the 
FMCSRs to FMVSS No. 106, before those requirements were removed. NHTSA 
tentatively concluded that to ensure the continued safety of commercial 
motor vehicle braking systems, the substantive specifications of the 
SAE Recommended Practices should be incorporated into FMVSS No. 106, 
with a few exceptions. This would involve, among other changes, 
establishing a new category in FMVSS No. 106 for plastic air brake 
tubing, end fittings, and tubing assemblies.
    NHTSA's decision to grant the petition was also based on the fact 
that FMVSS No. 106 had not been substantially updated in many years. 
The agency noted that most of the substantive requirements currently in 
FMVSS No. 106 were originally based on SAE standards and American 
Society for Testing and Materials (ASTM) standards referenced therein. 
While the SAE and ASTM standards have been modified over time to keep 
pace with technological developments in the industry, the substantive 
requirements of FMVSS No. 106 have remained relatively unchanged. 
Therefore, NHTSA's proposed changes to FMVSS No. 106 took into account 
the substantial technological developments that have occurred and 
sought to align the standard's requirements with standard industry 
practices. Incorporating many of the SAE standards' performance 
requirements is consistent with Office of Management and Budget (OMB) 
Circular A-119, which directs federal agencies to use and/or develop 
voluntary consensus industry standards, in accordance with Pub. L. 104-
113, the ``National Technology Transfer and Advancement Act of 1995.''
    The agency's proposal differed as follows from the petition:
    First, instead of simply incorporating complete SAE standards by 
reference as the FMCSRs currently do, NHTSA proposed to incorporate 
only the specific requirements/specifications of the SAE standards that 
are either more rigorous than those in FMVSS No. 106 or are not present 
at all in FMVSS No. 106.
    Second, the agency did not propose to limit the application of 
those SAE requirements/specifications to brake hose, tubing, and 
fittings used on commercial motor vehicles. NHTSA tentatively concluded 
that all brake hose, tubing, and fittings can and should meet the SAE 
requirements/specifications, regardless of their end use.
    Third, although NHTSA agreed with the petitioners that proposed 
changes to FMVSS No. 106 should be based on the most recent versions of 
the SAE standards instead of the older versions cited in the FMCSRs, 
the agency noted that a number of SAE's standards had been updated 
since the joint petition was filed. Accordingly, NHTSA proposed to rely 
on the most recent versions of the SAE standards.
    Fourth, the agency did not propose to incorporate SAE standards 
relating to copper tubing, galvanized steel pipe, or end fittings used 
with metallic or non-metallic tubing. These materials are occasionally 
used in chassis plumbing and since these products are not considered to 
be brake hoses, NHTSA stated its belief that they are inappropriate for 
inclusion in FMVSS No. 106.
    Fifth, NHTSA did not propose to incorporate the material and 
construction specifications for Type A and Type B tubing contained in 
SAE J844, Nonmetallic Air Brake System Tubing, and SAE J1394, Metric 
Nonmetallic Air Brake System Tubing because the agency tentatively 
concluded that incorporating those material specifications would be 
design-restrictive.
    Sixth, NHTSA did not propose to incorporate the manufacturer 
identification requirements in SAE J1401, Hydraulic Brake Hose 
Assemblies for Use with Nonpetroleum-Base Hydraulic Fluids, because it 
tentatively concluded that the manufacturer identification requirements 
already present in FMVSS No. 106 are sufficient.

III. Summary of Comments

    In response to the May 15, 2003 NPRM, NHTSA received comments from 
the following eleven organizations and companies: SAE International 
(SAE) and ASTM International (ASTM), which are automotive and 
industrial standards organizations; Intertek Testing Services 
(Intertek), a company that tests brake hoses and other products; and 
the following manufacturers of brake hose products; Goodyear Engineered 
Products (Goodyear), Dana Coupled Products (Dana), Saint-Gobain 
Performance Plastics (SGPPL), Degussa High Performance Polymers (HPP), 
Parker Hanifin Corporation and Atofina Chemical, Inc. (Parker/Atofina), 
SMC Corporation of America (SMC), and DuPont Engineered Polymers 
(DuPont).
    Parker/Atofina submitted joint comments to the NPRM and are the 
successor companies to the parties to the joint petition for rulemaking 
submitted to NHTSA in 1998. Intertek Testing Services conducts 
laboratory testing of various products, including brake hoses, and also 
contracts with NHTSA to perform compliance testing of brake hoses. 
DuPont submitted comments on June 16, 2004, after the NPRM's comment 
closing date of July 14, 2003. However, NHTSA has fully considered 
DuPont's comments.
    The commenters generally supported NHTSA's proposal to amend FMVSS 
No. 106 to include the latest requirements in the SAE brake hose 
standards for hydraulic, vacuum, and air brake hose and tubing. The 
commenters raised numerous technical issues, however. For many of 
proposed tests, commenters provided detailed information on test 
methods and procedures. The comments also generally supported NHTSA's 
proposal to specify requirements for plastic brake tubing, and plastic 
air brake tubing assemblies and end fittings.

IV. Agency Decision To Issue a Final Rule

    In this document, NHTSA announces that it has decided to issue a 
final rule. We have made this decision after we

[[Page 76300]]

have thoroughly reviewed the public comments. We have made a number of 
changes in response to the comments. In the few instances where we did 
not adopt a comment, we explain why, in light of the need for safety.
    We believe that the updated brake hose standard, which combines the 
most rigorous requirements of the latest SAE standards, and of FMVSS 
No. 106, meets the need for safety. Significant changes have been made 
to existing brake hose standards, with the effect of upgrading the 
performance requirements and test procedures relating to: (a) Hydraulic 
brake hose; (b) air brake hose; and (c) vacuum brake hose. In addition, 
we are establishing requirements more specifically tailored for plastic 
air brake tubing, plastic air brake tubing assemblies and end fittings. 
NHTSA seeks to ensure safe plastic air brake tubing, and plastic air 
brake tubing assemblies and end fittings.
    In the following sections, we discuss the public comments to the 
NPRM, our response to the comments, and how (if this is the case) the 
proposed language in the NPRM has been amended in response to the 
comments.

V. Issues Raised by Commenters and NHTSA's Responses

A. Issues Relating to All Types of Brake Hose

1. Use of the Term ``Burst''
    Intertek stated that several proposed requirements in the NPRM 
referred to the word ``burst'' and noted that ``burst'' was not defined 
in the proposed regulatory text. Intertek cited SAE J1401, stating that 
leaks or burst is ``loss of test fluid from the brake hose assembly 
other than by designated inlet(s) and outlet(s).'' NHTSA notes that in 
S4 of FMVSS No. 106, ``rupture'' is defined as any failure that results 
in separation of a brake hose from its end fitting or in leakage. In 
this final rule, NHTSA retains ``burst'' as a term that is presently 
used in FMVSS No. 106 to describe a required test or test pressures (as 
in, for example, a table of burst pressures). Whenever the performance 
requirement of a brake hose is specified, the word ``rupture'' has been 
substituted. This is consistent with existing FMVSS No. 106 text and 
avoids the need to add a definition of ``burst'' to S4.
2. Use of the Term ``Any''
    SMC Corporation commented that S11.3 Test requirements (for plastic 
air brake tubing, plastic air brake tubing assemblies, and plastic air 
brake tubing end fittings) stating ``* * * capable of meeting any of 
the requirements'' should be changed to ``all of the requirements.'' 
[Emphasis added.] NHTSA is not making this recommended change. The term 
``any'' has a very specific meaning in the Federal motor vehicle safety 
standards, including FMVSS No. 106. 49 CFR Part 571.4 specifies that 
``(t)he word any, used in connection with a range of values or set of 
items in the requirements, conditions, and procedures of the standards 
or regulations in this chapter, means generally the totality of the 
items or values, any of which may be selected by the Administration for 
testing. * * * Thus, use of the term ``any'' has the effect of 
including all of the requirements.
3. Constriction Test Method
    The constriction test is conducted to ensure the opening in the 
brake hose is large enough for the medium (i.e., brake fluid or air) to 
flow through unimpeded. In the NPRM, NHTSA noted that while the 
existing FMVSS No. 106 includes constriction requirements, i.e., 
requirements for minimum pass-through diameter, it does not specify a 
test procedure. The agency noted that two different constriction test 
procedures are available: A drop-ball test and a plug gauge test. The 
agency proposed to use a plug gauge method, similar to that in SAE 
J1401, that consists of a spherical end (sized at 64 percent of the 
brake hose nominal inside diameter for hydraulic brake hose and 66 
percent of nominal inside diameter for air brake hose) with a shank and 
handle that can be inserted into the brake hose end fitting. The weight 
of the gauge is specified as two ounces, and this weight assists the 
passage of the spherical end through the fitting. The agency stated 
that it welcomed comments both on its proposal to specify a plug gauge 
test instead of a drop-ball test and on the differences between the 
plug gauge test specified in SAE J1401 and the one the agency proposed.
    Goodyear commented on the proposed constriction test method for air 
brake hoses, and Dana similarly commented on the constriction testing 
for hydraulic brake hoses.
    Goodyear stated that air brake hose manufacturing may result in 
curvature in the hose that could impede the gauge from fully entering 
the brake hose. The agency notes that the proposed regulatory text at 
S6.12 provided that the brake hose is held in a straight position to 
overcome such a problem. Holding the brake hose in a straight position 
allows the gauge to fully enter the brake hose. Goodyear stated that 
the general practice is to use the rolling ball test (also described in 
the NPRM, but not proposed as a test method), and recommended that the 
constriction test method be left to the discretion of the hose/assembly 
manufacturer. NHTSA notes that the rolling ball test is similar but not 
identical to the drop ball test. The drop ball test relies on the force 
of gravity for the ball to drop vertically through the hose; the 
rolling ball test relies on a side-to-side motion by the tester to go 
through the hose.
    Dana agreed with the plug gauge test but recommended including the 
option of a drop ball test or an extended plug gauge for hose assembly 
end fittings that by design do not offer a passage through which a plug 
gauge can be readily inserted. Dana stated that either the extended 
plug gauge or the rolling ball would permit constriction inspection 
without cutting the hose.
    In response to the comments about the drop ball test vs. the 
extended plug gauge test, NHTSA begins by noting that S5.3 Test 
requirements in both the existing FMVSS No. 106 and proposed regulatory 
text for FMVSS No. 106 indicate that a hydraulic brake hose is only 
subjected to one of the test conditions in S5.3.2 through S5.3.11 
(existing text) or through S5.3.13 (proposed text) after having met the 
constriction test requirement in S5.3.1. There is a similar provision 
for air brake hoses in S7.3 Test requirements. Thus, each brake hose 
tested to any of the conditions in FMVSS No. 106 would first be 
inspected for constriction test compliance. If the end fittings or 
other features of the brake hose do not permit the plug gauge to be 
used, or would require cutting of the brake hose or end fitting to do 
so, then constriction testing cannot be conducted prior to one of the 
other performance tests. Therefore, NHTSA is including the drop ball 
test in the final rule to provide NHTSA and the manufacturers an 
alternative to the plug gauge test. In addition, the use of an extended 
length plug gauge is also included for similar reasons. This will 
provide some flexibility in the constriction test method for the 
variety of end fittings likely to be encountered in compliance testing. 
None of these provisions would preclude a brake manufacturer or 
assembler from using other means to perform constriction testing, since 
the purpose of the constriction test is to verify the final inside 
diameter of a brake hose assembly in a pass-fail manner.
4. Specification of Ozone Concentration
    Many commenters noted an incorrect specification of ozone 
concentration in the preamble to the NPRM, where the

[[Page 76301]]

units ``parts per million'' were stated, rather than the correct 
``parts per hundred million.'' The agency agrees that this was an 
oversight, and notes that a change to the regulatory text is not 
needed, as the proposed text specified the correct units.

B. Hydraulic Brake Hoses

1. General Hydraulic Brake Hose Comments in Response to the NPRM
    In general, the commenters agreed with the agency's proposal to 
upgrade the hydraulic brake hose requirements in FMVSS No. 106 to those 
requirements in SAE J1401. In the NPRM, the agency proposed to keep all 
hydraulic brake hose requirements in one section, rather than creating 
separate categories of brake hoses for commercial vehicles and non-
commercial vehicles. Dana stated that it agrees with this position, and 
does not see this as burdensome to the industry as a whole, as most 
brake hose manufacturers and light vehicle original equipment 
manufacturers (OEM) requirements currently exceed the SAE 
specifications. Goodyear stated that it currently brands, tests, and 
certifies its brake hoses to both FMVSS No. 106 and SAE requirements.
    Parker/Atofina was the only commenter to oppose the upgrade in 
performance standards for all hydraulic brake hoses, stating that 
hydraulic brake hoses used on recreational boat trailers, motorcycles, 
all-terrain vehicles (ATVs), snowmobiles, and off-road tractors/
trailers and farm implements do not require the same level of severe 
service performance requirements. NHTSA notes that of the vehicle types 
listed by Parker/Atofina, the upgraded requirements would only apply to 
``motor vehicles,'' (i.e., boat trailers and on-road motorcycles). The 
other vehicle types are not ``motor vehicles'' regulated by NHTSA. 
Parker/Atofina also asserted that the FMVSS No. 106 upgrade for all 
hydraulic brake hoses is unnecessarily cost prohibitive, but provided 
no cost data for the agency to evaluate.
    NHTSA is not adopting Parker/Atofina's recommendation because NHTSA 
does not wish to create separate categories of hydraulic brake hose 
(e.g., ``commercial'' and ``non-commercial.'') To avoid brake system 
failures caused by brake hose ruptures, we believe there is a safety 
need for all motor vehicle brake hose to meet rigorous performance 
requirements.
2. Hydraulic Brake Hose Manufacturer Identification Requirements
    Parker/Atofina requested that the agency incorporate into FMVSS No. 
106 the full manufacturer identification requirements as provided in 
SAE J1401. Parker/Atofina states that the agency may not realize that 
hydraulic brake hoses as defined in SAE J1401 more clearly describe the 
performance, markings, and requirements for hydraulic brake hose 
compared with those currently existing in FMVSS No. 106.
    In response, NHTSA notes that the requirements for hose 
manufacturer identification in SAE J1401 are that the hose shall be 
either embossed or imprinted (three-dimensional) on the brake hose 
cover with the manufacturer's name, or employ the market yarn color 
scheme (Appendix A) as registered with the Rubber Manufacturers 
Association. In addition, the marker yarn color scheme or name 
trademark on the brake hose cover shall be registered with the SAE. SAE 
J1401 does not include any provision for a brake hose assembler to add 
identifying markings to the end fittings or by means of a band placed 
around the brake hose assembly; only requirements for the manufacturer 
of the brake hose material are specified.
    NHTSA further notes that the FMVSS No. 106 requirements for 
hydraulic brake hose manufacturer or assembler identification are 
specified in S5.2 Labeling. The brake hose manufacturer's designation 
(symbol, text, etc.) is registered with NHTSA and labeled on the 
outside of the hose. The brake hose assembler's designation is included 
on a band placed around the brake hose assembly, or may be stamped into 
an end fitting. Labeling exceptions are provided for brake hose 
assemblies included as part of a newly-manufactured vehicle. For these 
reasons, NHTSA determines that the current labeling requirements fully 
meet the agency's needs for identifying the manufacturers of brake hose 
or brake hose assemblers. Therefore, in this final rule, NHTSA will not 
require any additional labeling or manufacturer identification 
requirements for hydraulic brake hoses.
3. Expansion and Burst Strength (Volumetric Expansion) Test
    NPRM--The expansion test is conducted at test pressures of 1,000 
psi and 1,500 psi and is followed by a burst strength test. NHTSA 
proposed to add language to S5.3.2 specifying that after the hydraulic 
brake hose assembly withstands water pressure of 4,000 psi for two 
minutes without rupture, it must ``not rupture at less than 7,000 psi 
for 1/8 inch, 3 mm, or smaller diameter hose, or at less than 5,000 psi 
for a hose with a diameter larger than 1/8 inch or 3mm (S6.).''
    Public Comments and NHTSA Response--Goodyear indicated that in 
addition to the expansion test pressures of 1,000 psi and 1,500 psi, 
SAE J1401 includes a third test at a higher pressure of 2,900 psi, and 
recommended that it be added to FMVSS No. 106.
    In considering this issue, we note that it was an oversight not to 
include the third pressure in the NPRM. We did, however, explain that 
we were generally proposing to incorporate those SAE J1401 requirements 
that are more rigorous than FMVSS No. 106. We therefore believe it is 
reasonable to add this pressure for the final rule. We are therefore 
adding the third test at 2,900 psi to S5.3.2 and to Table 1.
    We note, however, that SAE J1401 does not include any expansion 
requirements for the larger, \1/4\ inch and 6 mm brake hose sizes that 
are included in FMVSS No. 106. Further, the agency is not able to 
extrapolate the existing values in FMVSS No. 106, Table 1, Maximum 
Expansion of Free Length Brake Hose, to determine what expansion limits 
would be appropriate for the larger brake hose sizes tested at the 
2,900 psi expansion test. We are therefore not including at this time 
expansion requirements for the larger brake hose sizes tested at the 
2,900 psi expansion test.
    Intertek stated that for the final burst strength requirement in 
the expansion and burst strength tests, the proposed regulatory text 
included a 7,000 psi burst strength for \1/8\ inch, 3 mm or smaller 
diameter brake hoses, and a 5,000 psi burst strength for \3/16\ inch, 4 
mm, or larger diameter brake hoses. Intertek noted that this does not 
include a defined specification for those brake hoses with diameters 
falling between \1/8\ inch and \3/16\ inch, or between 3 mm and 4 mm. 
To clarify this issue, in the final rule, the agency has changed the 
regulatory text to state that brake hoses with diameters greater than 
\1/8\ inch or 3 mm shall not rupture at less than 5,000 psi.
4. Tensile Strength
    NPRM--NHTSA proposed that the SAE J1401 fast-pull test and 370 
pound strength requirement be incorporated into FMVSS No. 106. The 
agency also proposed to update the ASTM reference for tension testing 
machines to the latest version of the standard practice.
    The agency notes that in the NPRM, the water absorption and tensile 
strength requirements were labeled as S5.3.5. However, S5.3.5 as 
currently specified in FMVSS No. 106 are the water absorption and burst 
strength

[[Page 76302]]

requirement test. In this final rule, NHTSA corrects the error. The 
water absorption and tensile strength requirements are at S5.3.6.
    Public Comment and NHTSA's Response--At S6.4 of FMVSS No. 106, the 
tensile strength test procedures are specified. ASTM commented that the 
latest version of ASTM standard E 4 Standard Practices for Force 
Verification of Testing Machines was E 4-02. In preparing this final 
rule, NHTSA determined that E 4 has been revised to E 4-03. NHTSA is 
therefore incorporating by reference ASTM standard E 4-03 into FMVSS 
No. 106 at S6.4.
5. Water Absorption and Pressure Test, Tensile Strength, and Whip 
Resistance
    NPRM--NHTSA did not propose any changes to the existing water 
absorption requirements of FMVSS No. 106 but did propose to incorporate 
SAE J1401's fast-pull test and 370-pound strength requirement into 
Standard No. 106's tensile strength test procedure. Accordingly, after 
being conditioned in water for 70 hours, hydraulic brake hose assembly 
would be required to meet these heightened tensile strength 
requirements.
    The agency stated that the immersion of the brake hose in water for 
70 hours as specified in S6.5 of FMVSS No. 106 is the same as that 
specified in SAE J1401. However, while the time specification of 70 
hours is the same, the preparation of the brake hose specimen and the 
water soak method are different between the two standards. The 
preparation in FMVSS No. 106 specifies removal of 1 \1/8\ inches of 
outer brake hose cover (if present) at the center of the brake hose, 
without damage to any reinforcing material. Brake hoses tested to SAE 
J1401 do not have any cutting of the hose. Another difference between 
SAE J1401 and FMVSS No. 106 is that FMVSS No. 106 specifies soaking the 
brake hose in distilled water at room temperature (75 degrees 
Fahrenheit) while J1401 specifies an elevated water temperature of 185 
degrees Fahrenheit.
    Public Comments and NHTSA Response--Intertek commented that water 
temperature is not a great factor regarding the degradation of brake 
hoses, but that removal of the outer cover may influence the test 
results because of the possibility of damage to the reinforcing braid 
when the cover is cut. Goodyear stated that the SAE J1401 procedure was 
developed to eliminate the potential of yarn damage that may occur when 
the outer cover of the brake hose is removed by cutting. Goodyear 
recommended that the water soak procedure in SAE J1401 be used in FMVSS 
No. 106. Dana noted the discrepancies in the two standards, and stated 
that it prefers the SAE procedure because it is easier for the 
technician to perform and has less risk of inadvertent damage to the 
brake hose. Further, Dana stated its belief that the results of the SAE 
J1401 and FMVSS No. 106 test methods are similar although the 
comparison data is about a decade old.
    NHTSA agrees with the commenters that by using the SAE J1401 water 
soak procedure, the likelihood of unintended damage to the brake hose 
during the process of removing the cover will be eliminated. Thus, in 
the final regulatory text, NHTSA adopts the water soak procedure in SAE 
J1401.
6. Low Temperature Resistance Test
    NPRM--NHTSA did not propose any changes in Standard No. 106's low 
temperature resistance requirements/procedures.
    Public Comments and NHTSA's Response--Dana and Goodyear stated that 
while FMVSS No. 106 specifies a temperature of minus 40 degrees 
Celsius, SAE J1401 specifies a lower temperature range of minus 45 
degrees Celsius to minus 48 degrees Celsius. Both Dana and Goodyear 
recommended the use of the lower test temperature as better reflecting 
the capabilities of the materials used in current day brake hoses.
    In the final rule, NHTSA adopts the lower temperature specification 
recommended by Dana and Goodyear and as provided in SAE J1401.
7. Brake Fluid Compatibility, Constriction, and Burst Strength
    NPRM--In the NPRM, NHTSA proposed to use the latest SAE reference 
RM brake fluid for the brake fluid compatibility test. Because the RM-
66-05 fluid has superseded the RM-66-03 fluid, NHTSA did not propose 
any change in the type of fluid specified for conditioning the hose. 
NHTSA proposed, however, to increase the conditioning temperature in 
FMVSS No. 106 to 248 degrees Fahrenheit.
    Public Comments and NHTSA's Responses--Goodyear indicated in its 
comments that the NPRM language regarding compatibility fluid was 
incorrect with respect to the version of the SAE compatibility fluid 
referenced in the existing FMVSS No. 106 and SAE J1401. NHTSA notes 
that SAE RM-66-04 is currently referenced in FMVSS No. 106, and SAE RM-
66-05 is referenced in SAE J1401 (June 2003). The agency correctly 
identified the compatibility fluid in the proposed regulatory text as 
SAE RM-66-05 and therefore will make no change in the final rule.
    Goodyear recommended that FMVSS No. 106 reference the latest or 
current SAE fluid and not cite the specific version (e.g., -04 or -05). 
NHTSA will not adopt this recommendation. NHTSA will maintain the 
current system of referencing a specific version of the compatibility 
fluid, and perform periodic rulemaking as new versions of the test 
fluid are developed. In this way, the public will have an opportunity 
to comment on new versions of the compatibility fluid before it is 
incorporated by reference into FMVSS No. 106.
8. End Fitting Corrosion Resistance
    NPRM--Instead of referencing either ASTM B117-64 or ASTM B 117 
Appendix B, both of which are outdated, NHTSA proposed to change the 
reference in FMVSS No. 106 to the most recent set of ASTM 
specifications for salt spray chambers, which are found in ASTM B117-
97. NHTSA did not propose any other changes to the end fitting 
corrosion resistance requirements/procedures in FMVSS No. 106.
    Public Comment and NHTSA Response--ASTM commented that the latest 
revision of ASTM standard B 117 Standard Practice for Operating Salt 
Spray (Fog) Apparatus is B 117-02. In preparing this final rule, the 
agency determined that B 117 has been revised to B 117-03, and is 
incorporating B 117-03 in FMVSS No. 106 at a new S6.11, End fitting 
corrosion test. There are no substantive differences between B 117-02 
and B 117-03.
9. High Temperature Impulse Test
    NPRM--NHTSA proposed incorporating the high temperature impulse 
test from SAE J1401 into FMVSS No. 106.
    Public Comment and NHTSA Response--Goodyear noted that in the 
NPRM's preamble, the text incorrectly stated that the impulse test is 
conducted in an air chamber at 259 degrees Fahrenheit, while the 
correct specification is 295 degrees Fahrenheit. No change is needed to 
the final rule regulatory text, as the correct temperature was 
specified in the NPRM's draft regulatory text.

C. Air Brake Hoses

1. Construction and Labeling
    NPRM--NHTSA proposed that plastic air brake tubing be regulated in 
its own section in FMVSS No. 106 since it differs significantly in 
construction and material properties from elastomeric

[[Page 76303]]

rubber hoses. Therefore, NHTSA proposed that any references to 
synthetic or natural elastomeric rubber be deleted from S7 
Requirements--Air brake hose, brake hose assemblies, and brake hose end 
fittings of FMVSS No. 106 since it will no longer be necessary to 
differentiate rubber hoses from plastic tubing in S7 and S8. The 
proposed text in the NPRM also removed references to ``outside diameter 
(OD)'' from S7 and S8 of FMVSS No. 106 since OD measurements are 
generally only applicable to tubing, which NHTSA proposed to address in 
the new section for plastic tubing.
    NHTSA also proposed to specify in S7.2.1(e) of FMVSS No. 106 the 
labeling scheme that is to be used for air brake hose that meets the 
dimensional requirements of more than one type of end fitting (A, AI, 
or AII). The proper labeling of such hose has been addressed in several 
of the agency's legal interpretation letters, and including this 
language in FMVSS No. 106 would serve to minimize confusion on this 
issue. The proposed text also stated that a hose intended for use with 
more than one type of end fitting may be labeled as such, but is not 
required to be so labeled. This provides flexibility for hose 
manufacturers to determine how they intend their hoses to be used, and 
would not require them to label hoses for multiple end fitting 
designations unless they so desire.
    Public Comments and NHTSA's Response--The SAE and Parker/Atofina 
stated that it is necessary to keep the references to synthetic or 
natural rubber in order to clearly indicate that the fittings intended 
for use with rubber air brake hose are not to be used with any type of 
plastic hose (which is similar to plastic tubing but is sized by inside 
diameter rather than outside diameter). Based upon the comments 
received, the agency determines that retaining the references to rubber 
provides beneficial information regarding the use of these brake hoses, 
and is retaining the existing FMVSS No. 106 language in the final rule.
    Comments from the SAE and Parker/Atofina describe the differences 
in the three types of air brake hose designated as Type A, Type AI, and 
Type AII. The SAE suggested notes for Table III describing the 
application of reusable and permanent crimped fittings to each type of 
hose. The SAE also recommended that the dimensional requirements for 
Type A hose for use with both reusable and permanent fittings be 
included in Table III. Parker/Atofina also recommended that the correct 
dimensions for Type A, AI, and AII hose be included in FMVSS No. 106, 
and that FMVSS No. 106 should conform to the specifications in SAE 
J1402 for these dimensions.
    Historically, NHTSA has declined to specify dimensions of end 
fittings, as there are too many different end fitting thicknesses and 
too many different types. NHTSA notes that the industry has 
standardized brake hose end fittings. Therefore, on the issue of 
dimensional requirements for air brake hose intended for use with 
permanently attached fittings, NHTSA has stated its belief in the May 
15, 2003 NPRM and in other rulemaking documents that it was not 
necessary to include those dimensional requirements in FMVSS No. 106. 
In the May 15, 2003 NPRM, NHTSA also stated that it believes that many 
of the brake hose assemblers are truck repair facilities that may be 
assembling brake hoses with permanently attached end fittings. It 
follows that these truck repair facilities must pay attention to the 
type of air brake hose being assembled, to ensure that the hose and end 
fitting are compatible. In the NPRM, NHTSA stated that it believes that 
air brake hose conforming to SAE J1402 is presently in use because of 
FMCSR requirements at 49 CFR 393.45.
    Regarding metric sizes of air brake hose, in the NPRM, NHTSA noted 
that dimensions for metric air brake hoses are not included in FMVSS 
No. 106, and solicited comments on the dimensions for metric air brake 
hose (for use with permanently attached, or reusable end fittings) that 
may be appropriate to include in FMVSS No. 106. Since it received no 
comments on this subject, NHTSA will not include metric air brake hoses 
in Table III.
    In the final rule, the agency is adopting the dimensional 
requirements for Type A air brake hose in Table III, as recommended by 
the SAE and Parker/Atofina, and is including the suggested notes for 
Table III. Table III's title, and its reference in S7.1, Construction, 
are changed to no longer reference ``reusable'' end fittings because, 
as the SAE indicates, the air brake hose in the table may be used with 
either reusable or permanent fittings. The agency concludes that it is 
also appropriate to slightly revise the regulatory text for S7.2.1(e) 
in Labeling to indicate that the markings on the air brake hose 
directly relate to its type as specified in Table III. As metric air 
brake hose is not included in Table III, the agency is specifying that 
it continue to be designated with the letter ``A.''
    NHTSA proposed in the brake hose labeling requirements in 
S7.2.1(e), a labeling provision for brake hoses manufactured for use 
with more than one type of end fitting, e.g., AI and AII. Upon further 
review and in light of the comments from the SAE and Parker/Atofina, 
NHTSA now believes that no such applications exist, because of the 
large differences in outside diameters between, for example, Type AI 
and Type AII brake hose. For these reasons, the multiple labeling 
provisions proposed in the NPRM are removed in the final rule.
2. High Temperature Resistance
    NPRM--The high temperature resistance test for air brake hose 
ensures that there are no cracks or disintegration due to proximity to 
high temperatures of vehicle components such as engines and 
transmissions. NHTSA proposed that FMVSS No. 106 adopt the smaller 
radii test cylinders from SAE J1402 and, for \1/8\ inch and 3 mm, 4 mm, 
and 5 mm hose, NHTSA proposed that the test cylinder radius of 1 inch 
as specified in SAE J1402 for \3/16\ inch hose also be used for these 
hose sizes. As currently indicated in Table IV of FMVSS No. 106, the 
larger metric sizes of hose (6 mm and above) numerically correspond 
closely to inch sizes of hose, for example, 6 mm (0.236 inch) is very 
close to \1/4\ inch (0.250 inch). Accordingly, NHTSA proposed to apply 
the test cylinder values from SAE J1402 to metric sizes of hose as 
currently specified in Table IV of FMVSS No. 106. As to SAE J1402's 
exclusion of fabric-covered air brake hose from the external inspection 
requirement, NHTSA disagreed that external inspection of such hose is 
impractical and, therefore, did not propose to incorporate SAE J1402's 
exclusion.
    Public Comments and NHTSA's Response--The SAE and Parker/Atofina 
provided similar comments regarding the proposed test cylinder radii 
that NHTSA raised in the NPRM. The test cylinder radii were proposed to 
be decreased from the current values in FMVSS No. 106, Table IV, to 
smaller values from SAE J1402, Table 4--Radius for High Temperature 
Resistance Test (small radius). For example, the test cylinder radius 
for a \3/8\-inch air brake hose in existing FMVSS No. 106 is 3\1/2\ 
inches while the test cylinder radius in SAE J1401 for the high 
temperature resistance test is 1\3/4\ inches, or one-half the size.
    The SAE and Parker/Atofina stated that SAE J1402 is going to be 
revised to remove the small radius test cylinders from the high 
temperature resistance test. However, in this final rule, the agency is 
making FMVSS No. 106 consistent with the current version of SAE J1402, 
but will be willing to

[[Page 76304]]

consider future alignments between the two standards in future 
rulemaking.
    The agency also notes that in the NPRM, the incorrect value of 3 
inches for the large test cylinder was specified for \3/8\ inch hose. 
NHTSA has corrected the value to 3\1/2\ inches in this final rule.
    NHTSA notes that in the NPRM, incorrect test cylinders were 
included in the proposed Table IV for the adhesion test of wire-
reinforced hose. The agency stated that the values from SAE J1402, 
Table 4, should be used (small radius), while in fact SAE J1402 
references the radii in Table 1 for this test (large radius). In the 
final rule, NHTSA retains the correct test cylinder values without 
change.
    Comments from the SAE and Parker/Atofina note that the \1/8\ inch 
size of air brake hose is not produced, therefore, the test cylinder 
specification for that size hose is not needed in Table IV of FMVSS No. 
106. The agency agrees and in the final rule, removes references to \1/
8\ inch size of air brake hose from Table IV.
    As currently stated in FMVSS No. 106, the required performance of a 
brake hose after being subjected to the test requirements in the high 
temperature test is that the brake hose shall not show external or 
internal cracks, charring, or disintegration visible without 
magnification. Under the high temperature resistance requirements in 
SAE J1402, the external surface of fabric-covered hoses is excluded 
from this inspection, stating that visual inspection is not practical. 
The agency proposed in the NPRM to keep the requirements in FMVSS No. 
106 for external inspection and not include the SAE J1402 exclusion. 
Both the SAE and Parker/Atofina commented that the SAE J1402 exclusion 
be kept in place. SAE commented that for hoses covered with a textile 
braid (fabric-covered), this braid does not show cracks from exposure 
to ozone nor does it crack due to the high temperature test.
    NHTSA does not understand the need to exclude external inspection 
of the hose if, as Parker/Atofina and the SAE comments indicate, those 
hoses with textile braid covering will not crack. The inspection is 
visual, and does not require special equipment or magnification, nor 
does it require removal of the fabric covering to inspect the hose 
beneath it. By having such an exclusion, conceivably, a fabric-covered 
brake hose that did show external cracks would be considered to have 
passed the test. NHTSA does not believe there is any reason to add the 
exclusion for external inspection. Further, the agency is specifying 
only the larger test cylinder sizes for this test, and this should 
further minimize the likelihood of failure compared to the requirements 
currently in SAE J1402.
3. Low Temperature Resistance
    NPRM--NHTSA proposed that the internal surface inspection of air 
brake hose, as specified in SAE J1402, be incorporated into FMVSS No. 
106. However, the agency did not propose to incorporate SAE J1402's 
exclusion of fabric-covered air brake hose from external inspection.
    Public Comments and NHTSA's Response--The SAE and Parker/Atofina 
commented that the \1/8\ inch size of brake hose does not need to be 
included in Table IV of FMVSS No. 106. NHTSA agrees and has removed the 
\1/8\ inch size of brake hose from Table IV in the final rule. Both SAE 
and Parker/Atofina also asked that the external inspection of the hose 
for cracks excluded fabric-covered hoses, but for the same reasons as 
described in the discussion on high temperature test requirements, 
NHTSA does not include this exemption in the final rule.
4. Ozone Resistance
    NPRM--Since NHTSA proposed that the ozone concentration for 
hydraulic brake hose be changed from 50 pphm to 100 pphm, NHTSA 
proposed to specify the higher ozone concentration (100 pphm) for air 
brake hose as well. The agency tentatively concluded it is appropriate 
to specify the same concentration of ozone for testing all types of 
brake hoses.
    Public Comments and NHTSA's Response--SAE, Parker/Atofina, and 
Goodyear correctly indicated that the proposed ozone concentration 
should be specified as 100 parts per hundred million, not by parts per 
million. The correct concentration (100 parts per hundred million) is 
specified in this final rule.
    NHTSA notes that in the NPRM, the ozone test for air brake hose was 
incorrectly identified as S8.14. A new section of FMVSS No. 106 for the 
ozone resistance test is not needed since the ozone test is already 
included in S8.4. In this final rule, the ozone test is correctly 
identified as S8.4. Thus, the constriction requirements that were 
proposed to be in S8.15 are now in S8.14.
5. Adhesion
    NPRM--NHTSA proposed to incorporate the SAE J1402 adhesion test for 
wire-reinforced air brake hose into FMVSS No. 106, with the exception 
of the steel ball sizes as discussed below. Also, to incorporate SAE 
J1402's specifications into FMVSS No. 106, NHTSA proposed that rather 
than specifying steel ball diameters for each hose size, the steel ball 
should be specified as having a diameter that is 75 percent of the 
nominal inside diameter of the hose. This would allow for testing of 
any and all sizes of hose.
    The agency also proposed to specify use of a plug gauge rather than 
a steel ball for constriction testing of other types of hose to which 
FMVSS No. 106 applies. For the adhesion test, however, it would not be 
possible to use a plug gauge because the hose is closed off at both 
ends during the test. Accordingly, NHTSA proposed to specify the use of 
a steel ball to test air brake hose for adhesion. Finally, the agency 
proposed to update the ASTM tension testing machine reference in S8.9 
from the 1964 version currently in FMVSS No. 106 to the latest revision 
of that standard, Standard Practices for Force Verification of Testing 
Machines, Designation E4-99.
    Public Comments and NHTSA's Response--The SAE and Parker/Atofina 
commented that they prefer the 73 percent of nominal inside diameter 
specification, which would allow the use of standard size test balls. 
Also, the size difference between a 73 and 75 percent ball size is 
small (0.008 inches for a \13/32\-inch brake hose). NHTSA agrees that 
the difference is not significant and adopts the 73 percent requirement 
in the final rule.
    NHTSA also notes that the incorrect test cylinder radii were 
proposed for the adhesion test of wire-reinforced air brake hose. The 
small test cylinders from SAE J1402 Table 4 were proposed in the NPRM, 
but the correct radii from SAE J1402 Table 1 are included in this final 
rule.
6. Air Pressure (Leakage)
    NPRM--The SAE J1402 specifications for hose leakage are more severe 
than those presently in FMVSS No. 106. NHTSA proposed incorporating the 
flexure/pressure test from SAE J1402 into FMVSS No. 106, with some 
modifications. NHTSA noted that the test procedure in SAE J1402 
includes tolerances on the pressure requirements for determining 
whether the hose leakage rate is acceptable upon completion of the 
flexure test. The agency described how, if these tolerances were 
applied in various manners, it may not be possible to determine the 
pass/fail performance of a brake hose during a test.
    Therefore, in the NPRM, we proposed an alternative, to modify the 
requirements to ensure there would be a pass or fail criterion. NHTSA 
also proposed to modify SAE J1402's test

[[Page 76305]]

procedures by specifying the thickness of the orifice during the final 
leak check. The thickness of the orifice, and not only the diameter of 
the orifice, affects the rate at which air can be supplied to the hose. 
The rate at which air is supplied to the hose would be critical if a 
small amount of hose leakage is present during the final leakage test. 
NHTSA proposed specifying an orifice thickness of 0.032 inches (\1/32\ 
inch), which is the same thickness specified for the orifice in FMVSS 
No. 121 at S5.3.5, Control signal pressure differential for converter 
dollies and trailers designed to tow another vehicle equipped with air 
brakes. NHTSA tentatively concluded that this proposed orifice 
dimension would supply air at a greater rate than any thicker orifice 
while still providing sufficient mechanical strength to withstand the 
test conditions.
    The agency proposed to adopt the lowest test pressure (140 psi) in 
the brake hose during the leakage test from the range provided in SAE 
J1402 (140 to 160 psi). The applied supply pressure to a restrictive 
orifice was proposed to be at the midpoint of the pressure range, 150 
psi. Thus, the supply pressure exceeds the required pressure that is to 
be maintained in the brake hose, allowing a small amount of leakage to 
be present, but not permitting excessive leakage to be present.
    Public Comments and NHTSA's Responses--The SAE and Parker/Atofina 
both stated that the agency is proposing to change the SAE test, 
creating a new requirement. The commenters stated that it does not 
reflect good test methodology to require 150 psi supply pressure with 
no tolerance, or 140 psi with no tolerance in the brake hose within the 
two minute period. However, neither commenter recommended an 
alternative to NHTSA's proposal, other than to adopt the exact 
procedure in SAE J1402. Both commenters stated that the agency's 
proposal to adopt a thickness requirement for the orifice has some 
technical value.
    While the agency has considered the comments, the commenters did 
not provide recommendations as to test pressures that the agency could 
adopt in the final rule. The agency believes that by specifying the 
minimum required pressure of 140 psi in the brake hose, while supplying 
air at the mid-point pressure of 150 psi through an orifice of minimal 
thickness that is least restrictive to air flow, a reasonable balance 
in test conditions is achieved. Therefore, NHTSA is making final the 
air pressure (leakage) test that it proposed in the NPRM.
    NHTSA believes that measuring the leakage using a mass flow meter, 
as is done for test leaks of plastic air brake tubing, may be 
preferable to the method in this final rule. NHTSA may consider raising 
this issue in a future rulemaking.
7. Tensile Strength
    NPRM--As currently in effect, FMVSS No. 106 includes different 
tensile strength requirements for air brake hoses if those hoses are 
used: (a) Between the vehicle frame and axle, or between a towing and 
towed unit; or (b) in any other application. The tensile strength 
requirements for brake hose assemblies in the former case are 
significantly higher than those requirements in the latter case. 
Because the agency proposed separate requirements for plastic tubing in 
a new section of FMVSS No. 106, NHTSA proposed to delete the lower 
tensile strength limits for hoses that are used for purposes other than 
connections between a frame and axle or between a towed and towing 
unit, and require the higher tensile strength requirements for all 
brake hoses. SAE J1402 only includes the higher tensile strength 
requirements.
    The agency proposed that all rubber brake hoses meet the 
requirements for a hose that is used between a frame and an axle or 
between a towed and a towing unit. NHTSA tentatively concluded that 
rubber hoses are no longer used extensively for other purposes on heavy 
vehicles, as plastic tubing is used for most chassis plumbing of air 
systems. NHTSA tentatively concluded that these rubber hoses are of 
sufficient diameter to have the mechanical strength to meet the higher, 
frame-to-axle tensile strength requirements. NHTSA also solicited 
comments on any alternate tensile strength requirements that might be 
appropriate for rubber hoses.
    Public Comments and NHTSA's Response--The SAE recommended that the 
SAE J1402 tensile strength testing be adopted. SAE did not elaborate on 
its recommendation. Parker/Atofina recommended keeping the current 
FMVSS No. 106 requirements with the high and low tensile strength 
requirements depending on application of the hose assembly. Parker/
Atofina stated that the lower tensile strength requirements are still 
used in applications other than connections between a towed and a 
towing unit, and to raise these requirements to the higher tensile 
strength would add significantly to hose cost. No cost data was 
provided for the agency to evaluate.
    In evaluating the tensile strength test requirements, NHTSA notes 
that it proposed different tensile strength requirements for plastic 
air brake tubing depending on the application of the product (e.g., 
between towing and towed unit, or in chassis plumbing applications), 
based on the current tensile strength requirements for air brake hoses 
in S7.3.10 of FMVSS No. 106. The reason for the different strength 
requirements is to accommodate different styles of end fittings. Thus, 
the end fittings for a brake hose or plastic tubing used between a 
towing and towed vehicle provide the highest tensile strength possible 
to prevent separation of the end fittings. In other applications, such 
as chassis plumbing, lower tensile strength requirements apply that 
permit the use of fittings designed for ease of assembly on chassis 
plumbing (such as push-to-connect fittings used with plastic tubing).
    NHTSA did not believe that air brake hose is for chassis plumbing 
(having been replaced by plastic tubing) and therefore proposed to 
delete the lower tensile strength requirements for this type of brake 
hose. Parker/Atofina however, states that this is not the case, and the 
agency believes that Parker/Atofina is referring to the higher cost of 
high-strength end fittings and/or the longer assembly time required for 
these fittings. Therefore, in this final rule, the agency is not 
deleting the lower tensile strength requirements for end fitting 
retention for air brake hose, to avoid changes to vehicle manufacturing 
in situations where this type of air brake hose is used for chassis 
plumbing. The end fitting tensile strength requirements will therefore 
be similar for air brake hose and plastic air brake tubing.
8. Minimum Bend Radius
    NPRM--NHTSA tentatively concluded it would not be appropriate to 
add SAE J1402 requirements for minimum bend radius to FMVSS No. 106 
because FMVSS No. 106 regulates the properties of brake hoses as stand-
alone motor vehicle equipment rather than use requirements. NHTSA did 
not propose to include a reference to the minimum bend radii from Table 
1 in SAE J1402 as the minimum installation bend radii for brake hose as 
installed on vehicles.
    Public Comments and NHTSA's Response--Both the SAE and Parker/
Atofina asked that the minimum bend radii from Table 1 in SAE J1402 as 
the minimum installation bend radii for brake hose installed on 
vehicles be included to benefit users (installers) of the brake hose. 
The agency notes that in Section 3.3.1 of J1402, smaller installation 
radii may be appropriate for

[[Page 76306]]

some brake hoses. Therefore, in the final rule, NHTSA is not specifying 
installation bend radii. NHTSA believes individual brake hose 
manufacturers are in the best position to determine minimum bend radii 
for hose to be installed in motor vehicles.

D. Vacuum Brake Hoses

1. Swell (Fuel Resistance)
    NPRM--NHTSA proposed that Reference Fuel B as specified in SAE 
J1403 be used for the swell test in FMVSS No. 106. NHTSA also proposed 
that the plug gauge method (in lieu of the steel drop-ball method) be 
kept in place in TP-106 for swell testing of vacuum brake hoses.
    NHTSA proposed that the specifications of FMVSS No. 106 and SAE 
J1403 be combined as follows. Following the fuel conditioning using 
Reference Fuel B and the constriction test, each vacuum hose would be 
subjected to a vacuum of 26 inches of Hg for ten minutes, with no 
visible collapse or leakage of the hose permitted (as currently 
specified by FMVSS No. 106). Then, for hoses constructed of two layers 
or more, a layer adhesion test would be conducted with a specified 
performance of 8 pounds-per-inch minimum separation force (as specified 
by SAE J1403). NHTSA proposed that this adhesion test only be applied 
to multi-layer hoses for two reasons. First, the agency tentatively 
concluded that single layer hose cannot be tested easily. Second, NHTSA 
tentatively concluded that single layer hose that have lost mechanical 
integrity would not be able to pass the visual collapse or no leakage 
specification during the vacuum test and, as such, failure would 
already be detected prior to completion of the vacuum test.
    NHTSA also proposed to update the ASTM test procedure referenced in 
S10.7 for the swell test to the current revision, D471-98e1.
    Public Comments and NHTSA's Response--Goodyear supported the 
current SAE J1403 test sequence consisting of fuel soak, restriction 
(constriction) ball test, vacuum collapse test, and layer adhesion test 
with a minimum separation strength of 6 pounds per inch. Goodyear 
commented that the agency's proposed plug gauge for constriction 
testing, shown as Figure 4, has only three inches of length and would 
not be able to pass through a test sample of vacuum hose that is 12 
inches in length. Further, the vacuum brake hose may have some 
curvature that would not permit a straight gauge to pass through it. 
For these reasons, Goodyear recommended that a rolling ball be used to 
verify the internal dimensions of vacuum brake hose during the swell 
test.
    In responding, the agency begins by noting that pre-formed vacuum 
brake hoses would have significant curvature molded into them, and 
standard vacuum brake hose may also have some natural curvature as 
described by Goodyear. NHTSA also notes that in the existing and 
proposed FMVSS No. 106 regulatory text, the method of verifying the 
inside diameter of the vacuum brake hose is not provided. As noted in 
the NPRM, the method is identified as a plug gauge in the agency's 
current test procedure, TP-106. For the final rule, the agency has 
decided to provide the option of using a drop ball for both 
constriction tests and verification of the inside diameter during the 
swell test, and to also permit the use of a standard plug gauge or an 
extended length plug gauge. The fact that several options are provided 
to brake hose manufacturers is consistent with constriction testing for 
other types of brake hoses in FMVSS No. 106, where more than one method 
may be employed (by NHTSA and brake hose manufacturers) due to the 
variety of end fitting designs that may preclude the use of the plug 
gauge. In this final rule, NHTSA is incorporating into FMVSS No. 106 
the three constriction test methods to be used in the swell test.
    In the NPRM, NHTSA proposed an adhesion strength test requirement 
of 8 pounds per inch. Goodyear stated that the value should be 6 pounds 
per inch, as stated in SAE J1403. The correct value of 6 pounds per 
inch adhesion strength requirement is in this final rule.

E. Plastic Air Brake Tubing

1. General Comments
    In the NPRM, NHTSA stated that plastic air brake tubing is 
generally manufactured from nylon but the generic term, ``plastic'' is 
used to account for other types of plastic that may be used for air 
brake tubing. The comments on the proposal for requirements for plastic 
air brake tubing, plastic air brake tubing assemblies, and plastic air 
brake tubing end fittings fell into two groups: (a) Manufacturers 
currently manufacturing air brake tubing from polyamide (nylon) 
requesting that this material specification be included in FMVSS No. 
106; and (b) manufacturers that may be considering manufacturing air 
brake tubing from materials other than nylon, that did not support 
including this material specification (plastic) in FMVSS No. 106.
    Parker/Atofina stated that by not including additional material 
property tests into FMVSS No. 106, there would be insufficient 
safeguards for the performance of alternate tubing made from unproven 
and unspecified polymers that would create a significant product design 
risk. It also stated that the material specification of generic nylon 
is not design restrictive, but offers thermoplastic tubing 
manufacturers great latitude in product design options.
    SMC stated that not including the material specification in FMVSS 
No. 106 leads to an issue that is being addressed in the SAE committee 
that is responsible for SAE J2547, Alternate Nonmetallic Air Brake 
System Tubing. Namely, the test should be application specific and not 
a material validation test like the burst pressure test in SAE J844. 
Different tube material may affect the retention of the tubing in the 
fitting per the SAE J1131 requirements. Until further evaluation is 
conducted on the new tubing materials with all fitting supplied in the 
industry, leaving the material open to the tubing manufacturers' 
discretion may lead to problems with the tube connection.
    HPP stated that SAE J844 takes into account that the materials are 
polyamides. To exclude this requirement, additional tests would need to 
be introduced to ensure that long-term properties of tubing made from 
other materials meet the in-use requirements. HPP cited, for example, 
that there is no requirement for a high-temperature burst test at 
elevated pressures, while polyamides are known to possess the long-term 
properties for this requirement.
    DuPont stated that the agency correctly points out in the NPRM that 
a material and construction specification is design restrictive. It 
notes that while polyamides used under SAE J844 have performed with an 
admirable safety record, it has a negative impact on innovation and 
commerce. DuPont also encouraged the elimination of any reference to 
specific types of construction, specifically regarding Type A 
(unreinforced) and Type B (reinforced) tubing. DuPont stated that any 
style of construction that passes the rigorous test procedures and 
dimensional requirements set forth in the proposal should be 
permissible.
    In this final rule, NHTSA has decided to keep the generic 
terminology of plastic air brake tubing, rather than adopt the 
specification for nylon (polyamide) material. Regarding concerns that 
materials other than nylon might be inferior when used in air brake 
tubing, NHTSA notes that it proposed 24 performance test requirements

[[Page 76307]]

(proposed S11.3.1 through proposed S11.3.24), and is adopting twenty-
two of those requirements in the final rule. NHTSA believes that these 
extensive requirements will ensure that alternative air brake tubing 
materials are subjected to rigorous testing to provide safe service in 
air brake systems.
    HPP stated that if the requirements in SAE J844 are performed on 
air brake tubing made from materials other than nylon, additional tests 
might be appropriate, such as a high-temperature burst test. However, 
HPP did not provide any test parameters that the agency could evaluate. 
NHTSA notes in the section below that high-temperature conditioning 
requirements for plastic air brake tubing have been included for 
adoption in FMVSS No. 106.
    With regard to the agency's statements in the NPRM that air brake 
tubing must be either Type A, single layer, unreinforced construction, 
or Type B, two layer, reinforced construction, the agency has reviewed 
the comments on this subject and has decided not to adopt these 
requirements in the final rule. Additional details that formed the 
agency's decision on this subject are included in the sections below.
2. Construction
    NPRM--The NPRM solicited comments on whether air brake tubing 
should be designated as Type A--a non-reinforced, single-layer tubing 
(designated for small diameter tubing in SAE J844), or as Type B--
constructed from two layers of material with a reinforcing braid at the 
interface of the two layers (designated for large diameter tubing in 
SAE J844).
    Public Comments and NHTSA's Response--SMC cited the SAE J2547 as a 
standard currently in draft that will not restrict the tubing to have 
either a single wall or two walls with a reinforcement braid, but SMC 
did not provide any additional details on the SAE effort that the 
agency could consider regarding the final rule. SMC stated that Europe 
is currently using single wall tubing for all sizes used in the 
trucking industry. SGPPL proposed that if references to nylon are not 
included for air brake tubing, one solution would be to also eliminate 
references to reinforced, unreinforced, and single- or multi-layer 
tubing construction, but retain dimensional values including inside 
diameter, outside diameter and/or wall thickness.
    HPP stated that single layer tubing with an outside diameter of 10, 
12 and 16 millimeters, or \3/8\, \1/2\, \5/8\ and \3/4\ inches, can 
meet SAE J844 requirements and should be permitted in FMVSS No. 106. 
HPP stated that from technical and safety standpoints, there is no need 
for reinforced tubing for the larger diameter applications.
    As earlier noted, DuPont believed that there was no need to include 
references to specific types of construction in FMVSS No. 106, because 
any style of construction that passes the rigorous test procedures and 
dimensional requirements as described in the NPRM should be 
permissible.
    The agency agrees with the comments from SMC, SGPPL, HPP, and 
DuPont that construction and reinforcement requirements do not need to 
be included in FMVSS No. 106. NHTSA believes that the safety of plastic 
air brake tubing will be ensured by the 22 tests specified in this 
final rule.
    Parker/Atofina stated that the NHTSA proposal not to include the 
construction and material specifications for Type A and Type B tubing 
as specified in SAE J844 is inappropriate and potentially unsafe to 
users. It stated that by not including additional material property 
tests into FMVSS No. 106 to safeguard the performance of alternate 
tubing made from unproven and unspecified polymers creates a 
significant product design risk. It suggested including test 
requirements for battery acid resistance, high temperature burst, high 
temperature heat aging, and moisture absorption to help prevent the use 
of unsuitable materials. HPP made similar comments regarding the need 
for additional tests such as an elevated temperature burst test if 
nylon is not specified as the tubing material. HPP stated that air 
brake tubing can be exposed to temperatures in the 80 to 100 degree 
Celsius (176 to 212 degrees Fahrenheit) range.
    NHTSA notes that the NPRM proposed to amend FMVSS No. 106 by 
including, for plastic air brake tubing, tests for moisture absorption, 
high temperature resistance, high temperature conditioning with low 
temperature impact resistance, boiling water conditioning with low 
temperature impact resistance, and high temperature conditioning and 
collapse resistance. All of these test requirements have been 
incorporated into the final rule. Parker/Atofina did not identify the 
parameters of the suggested battery resistance test, nor did they 
indicate why the test conditions proposed in NPRM involving, for 
example, high temperature conditioning of plastic air brake tubing, are 
insufficient for materials other than nylon. HPP indicated that 
temperatures up to 100 degrees Celsius (212 degrees Fahrenheit) can be 
experienced by plastic air brake tubing in use, and the agency has 
included high temperature conditioning tests for tubing in the 100 to 
110 degrees Celsius (212 to 230 degrees Fahrenheit) temperature range.
    NHTSA believes that the extensive series of test requirements that 
it is adopting in the final rule will be sufficient to ensure the safe 
performance of plastic air brake tubing made from materials other than 
nylon, and, as discussed in the section below on zinc chloride and 
methyl alcohol resistance, the agency may consider additional chemical 
resistance tests for plastic air brake tubing in the future. For 
example, DuPont cited the use of copolyester elastomer in air brake 
tubing. Therefore, in this final rule, the agency is not specifying 
that air brake tubing must be manufactured from nylon.
    NHTSA believes that although materials other than nylon, possibly 
constructed as unreinforced, single-layer tubing, have been developed 
and used (for example, in Europe), it does not automatically mean that 
these other materials or constructions (such as alternate plastic/non-
nylon tubing) can be applied to FMVVSS No. 106 without careful 
consideration. One of the main purposes of the agency's undertaking 
rulemaking on FMVSS No. 106 is to implement dimensional specifications 
for air brake tubing that currently do not exist in the standard, to 
preclude the sale or use of tubing that is not compatible with existing 
SAE J844 (or SAE J1394) tubing and end fittings used extensively in the 
United States. Alternate air brake tubing products that are developed 
will have to meet the extensive performance requirements for air brake 
tubing that are included in this final rule, and will also have to do 
so within the dimensional specifications that are also being adopted. 
NHTSA does not expect that inferior products of any type or size will 
meet these extensive requirements.
3. Labeling
    NPRM--NHTSA proposed to require air brake tubing to be labeled with 
the manufacturer identifying information at intervals of not more than 
6 inches, from the end of one legend to the beginning of the next. This 
represented no change from the FMVSS No. 106 labeling method already 
specified for brake tubing.
    Public Comments and NHTSA's Response--Parker/Atofina commented that 
based on their experience, the vast majority of plastic air brake 
tubing assembly lengths are greater than 15 inches. The tubing would be 
sufficiently marked for product tracking if the text marking repeat 
interval is not more than 15 inches. NHTSA believes that to facilitate 
identification of the hose

[[Page 76308]]

manufacturer, all brake hoses must be labeled to identify the 
manufacturer. To increase the labeling interval to 15 inches may 
increase the likelihood that a particular brake hose may not include 
the labeling information. Therefore, NHTSA will not adopt the 
suggestion of a 15-inch repeat interval for brake hose labeling.
    Parker/Atofina commented that the agency's proposal is too 
restrictive on manufacturers in order to maintain complete marking 
context and text liability on small diameter plastic tubing. 
Presumably, Parker/Atofina is referring to the requirement that the 
height of the labeling information be at least one-eighth of an inch. 
NHTSA notes the one-eighth inch height requirement has been in FMVSS 
No. 106 for many years. Further, Parker/Atofina did not suggest an 
appropriate lettering height for small diameters of air brake tubing. 
NHTSA is not changing the lettering height requirements in this final 
rule.
4. Dimensions and Tolerances
    NPRM--NHTSA proposed to incorporate into FMVSS No. 106 the 
dimension and tolerance requirements contained in SAE J844, and also 
SAE J1394 covering metric sizes of tubing, as Table VII of FMVSS No. 
106.
    Public Comments and NHTSA's Response--Parker/Atofina provided 
several recommendations for changes to Table VII, stating that for 
example, the tolerance for wall thickness should be similar for metric 
tubing that is close in size to that of an inch-sized tubing. The 
recommended changes are for the dimensional specifications of 10, 12, 
and 16 millimeter brake tubing. Parker/Atofina stated that these 
revisions are currently in process by the SAE under project S4-J844-01-
01. The agency has reviewed the recommended changes and notes in 
general that they serve to tighten the tolerances, compared to the 
values published in the NPRM. The agency is adopting Parker/Atofina's 
recommended changes.
    Parker/Atofina also noted that in Table VII, the outside diameter 
of the 3/8-inch brake tubing is specified as 9.69 millimeters, but the 
value should be 9.63 millimeters (as it appears in SAE J844). The 
agency notes this correction and includes it in the final rule.
5. One Hundred Percent Leak Test
    NPRM--NHTSA did not propose to incorporate the requirement in SAE 
J844 that requires tubing manufacturers to subject all air brake tubing 
to a 200-psi leak test. The agency stated its belief that this is a 
quality control test and not a measure appropriate to include in FMVSS 
No. 106.
    Public Comments and NHTSA's Response--Parker/Atofina commented that 
it believes that unless this requirement is mandated in FMVSS No. 106, 
manufacturers will not continue to perform the current quality 
inspections and controls, since the procedures represent added cost and 
require additional resources. NHTSA does not agree with this view. 
Manufacturers are required to take whatever steps are necessary to 
ensure that all of their plastic air brake tubing meets the full burst 
strength requirements in the standard ranging from 800 to 1,400 psi. 
NHTSA sees no additional safety need is met by requiring a 200 psi leak 
test in addition to a full strength burst test.
6. Burst Test
    NPRM--NHTSA noted that in the existing FMVSS No. 106 test 
procedures, water is specified as a test medium, but that SAE J844 does 
not specify a medium. NHTSA considered air to be the more appropriate 
test medium for plastic air brake tubing rather than water. NHTSA 
proposed changing the burst strength requirements in FMVSS No. 106 to 
the higher values in SAE J844, and specifying air as the test medium 
rather than water. NHTSA proposed that the pressure in the tubing be 
increased in a period of 5 seconds because using the range of 3 to 15 
seconds in SAE J844 would specify testing at both 3 and 15 seconds and 
therefore would be too broad of a specification for use in FMVSS No. 
106.
    Public Comments and NHTSA's Response--HPP, SMC, Parker/Atofina and 
SGPPL all recommended water (HPP recommended water or oil) as the 
preferred test medium because of concerns for the safety for the person 
conducting the test and cost factors. After considering this concern, 
NHTSA has decided to specify water as a test medium in all burst tests 
in this final rule, except for one test where oil is specified due to 
very low test temperatures.
    SGPPL believes that FMVSS No. 106 should include a provision to 
prevent any conditioning of the air brake tubing sample prior to 
testing. SGPPL stated that polyamide material is hygroscopic and over 
time, will absorb water that will decrease the burst strength of the 
tubing. SGPPL recommended that the samples of tubing for the burst test 
be conducted on tubing as it is extruded from the production line.
    NHTSA does not agree that samples of tubing should be tested to 
burst strength requirement only at the point of production. Typically, 
the agency or test laboratories contracted to do testing for the agency 
will purchase samples of brake hose at a retail point of sale and those 
samples are required to meet the requirements in FMVSS No. 106. This is 
also reflective of the condition of brake hose when it is sold to and 
used by the public. The agency notes that this may require some 
diligence by the brake hose manufacturer to ensure that the 
manufacturer's distribution methods do not permit excessive degradation 
of brake hose products between manufacture and retail sale. NHTSA 
retains the existing FMVSS No. 106 requirement under S11 Test 
conditions (S13 in the NPRM) that brake hoses and brake hose assemblies 
must be at least 24 hours old, and unused.
    In the NPRM, NHTSA proposed to apply the test pressure in the brake 
tubing in 5 seconds during a burst test, instead of within the range of 
3 to 15 seconds as specified in SAE J844. NHTSA stated that if it were 
to adopt such a range, when NHTSA conducts the testing, the brake 
tubing would be required to meet the burst test at 3 seconds, at 15 
seconds, and at any point in between 3 and 15 seconds. NHTSA stated 
that the specification ``would be too broad of a specification for use 
in FMVSS No. 106.'' (See May 15, 2003 NPRM at page 26,398.) SGPPL 
stated that it does not exactly understand the agency's reasoning, but 
finds a range of 10 to 12 seconds to yield reliable, consistent 
results. SMC stated that instead of a timing requirement, a fixed flow 
rate should be specified rather than a time constraint, so that 
variable flow rates would not have to be used. However, SMC did not 
provide any details on what a suitable flow rate might be. Parker/
Atofina stated that thermoplastic tubing possesses strain rate 
dependent properties such that if a tubing burst pressure is achieved 
under 3 seconds, a higher burst strength without failure can be 
achieved. It further stated that there is no one standard burst test 
apparatus that manufacturers could use, and specifying an exact 5 
second timing requirement would require most costly and higher 
precision test equipment.
    NHTSA believes that based on the comments, it may be difficult to 
achieve the 5-second timing with the existing test equipment in use. 
The agency notes that in the case of the burst strength test for a 
hydraulic brake hose as specified in FMVSS No. 106 at S6.2, the 
pressure in the brake hose is increased at a constant rate of 15,000 
psi per minute. The precedent here is that a constant pressure increase 
rate is specified. Due to the costs and difficulty of achieving

[[Page 76309]]

the 5-second timing, in this final rule, NHTSA is going from a time 
increment to a pressure rate specification, as follows.
    The burst strength pressures proposed for plastic air brake tubing 
are specified in Table VIII, and the specified burst strength pressures 
range from a low of 800 psi for \3/4\3/4 -inch outside diameter tubing, 
to a high of 1,400 psi for 3/8-inch outside diameter tubing. To achieve 
an 800 psi pressure in 15 seconds, the application rate would be 3,200 
psi per minute. To achieve a 1,400 psi pressure in 15 seconds, the 
application rate would be 5,600 psi per minute. NHTSA agrees with 
Parker/Atofina's comment that faster pressure application rates can 
affect the outcome of the test results. Therefore, in the final rule, 
the agency is adopting a test pressure application rate of 3,000 psi 
per minute (3,200 psi per minute rounded down to 3,000 psi). The test 
pressure application rate of 3,000 psi per minute is consistent with 
SMC's stated preference for a fixed flow rate, and should not result in 
manufacturers' having to purchase new test equipment, as 3,000 psi per 
minute is a relatively slow pressure increase rate.
7. Moisture Absorption
    NPRM--NHTSA proposed incorporating the moisture absorption 
specification from SAE J844 into FMVSS No. 106. SAE J844 specifies a 
sample of air brake tubing is conditioned in a humidity chamber for 100 
hours, and the required performance is that the sample cannot exceed a 
two percent weight gain of absorbed moisture.
    Public Comments and NHTSA's Response--SGPPL stated that it believes 
the moisture absorption test is designed around polyamide (nylon) 
material and is design restrictive. SGPPL stated that the moisture 
absorption test is not performance-based and does not indicate failure. 
SGPPL also believed that the heat aging test, cold impact test, boiling 
water stabilization and burst tests would be satisfactory for 
evaluating the effects of moisture exposure on the properties of 
tubing. DuPont stated that although it has no objections to the 
moisture absorption test, it believed that it may be redundant to both 
the heat aged burst pressure test and the dimensional specifications 
test (boiling water conditioning and dimensional stability).
    Based on the information it received, NHTSA does not agree that 
this proposed requirement is design restrictive in favor of nylon 
tubing. NHTSA agrees, however, that as SGPPL states, failure of the 
moisture absorption test (excessive weight gain) does not directly 
indicate that the tubing has failed (e.g., ruptured). In its prior 
comments regarding burst strength testing, SGPPL indicated that 
moisture absorption can affect burst strength. While DuPont believes 
that the moisture absorption test is redundant to other proposed test 
requirements, NHTSA notes that these tests involve soaking the tubing 
in boiling water for 2 hours, whereas the moisture absorption test 
involves a humidity soak of 100 hours. The outcome of these soakings 
would be affected if there were a difference in the water or moisture 
absorption rate of different materials.
    NHTSA notes that in FMVSS No. 106 for hydraulic brakes, there are 
three performance requirements for hydraulic brake hose related to 
water absorption. After the hose is immersed in hot water for 70 hours 
(as specified in this final rule), brake hoses must pass a burst 
strength test, a tensile strength test, and a whip resistance test 
(separate tests, not conducted on the same hose).
    If a sample of plastic air brake tubing were to fail the proposed 
moisture absorption test, the agency would then be able to show how 
that failure relates to a lessening of motor vehicle safety. If the 
agency could demonstrate a corresponding reduction in one or more 
mechanical properties of the tubing, NHTSA would be better able to 
demonstrate a relationship to motor vehicle safety. Therefore, in this 
final rule, NHTSA adopts a burst pressure strength requirement, rather 
than a weight gain limit, as the required performance criteria for this 
test requirement. NHTSA is using the same burst pressure requirement as 
for other tests that involve conditioning of the tubing, which is 80 
percent of the burst strength in Table VIII.
8. Ultraviolet Resistance
    NPRM--NHTSA tentatively concluded that the plastic material used in 
nylon air brake tubing is significantly different from the materials 
used in rubber air brake hoses, and that plastic is susceptible to 
deterioration that can cause embrittlement due to exposure to 
ultraviolet light. NHTSA proposed to incorporate SAE J844's ultraviolet 
resistance test into FMVSS No. 106. SAE J844 includes an ultraviolet 
(UV) resistance test using an accelerated weathering device specified 
as the Q-Panel QUV test apparatus equipped with Phillips lamps, type 
UVS-340. NHTSA did not refer to any brand name of equipment in the 
proposed regulatory text of FMVSS No. 106. Presumably this test 
equipment, except for the special UV lamps, can be custom manufactured 
or purchased from a company such as Q-Panel.
    The agency proposed to reference the apparatus specified in ASTM 
G154-00, Standard Practice for Operating Fluorescent Light Apparatus 
for UV Exposure of Nonmetallic Materials, rather than the one specified 
in ASTM G53 because ASTM G154-00 is an updated version of ASTM G53. 
NHTSA also proposed to reference two additional ASTM standards: ASTM 
D4329-99, Standard Practice for Fluorescent UV Exposure of Plastics, 
which is currently referenced in SAE J844, and ASTM G151-97, Standard 
Practice for Exposing Nonmetallic Materials in Accelerated Test Devices 
that Use Laboratory Light Sources, which is not currently referenced in 
SAE J844, but may provide useful guidance for conducting UV testing.
    Public Comments and NHTSA's Response--SMC stated that the cost of 
purchasing a new system and performing the validation test on all sizes 
and configurations will need to be considered. SMC did not specify 
whether it has an older system that would need to be updated, or 
whether it has UV testing equipment. Parker/Atofina stated that the 
agency's proposal to require ASTM G-154-00 equipment will mandate that 
manufacturers will have to purchase a Q-Panel test apparatus with the 
Solar Eye irradiance measurement device. Parker/Atofina stated that 
this optional measurement device is not significantly relevant to the 
outcome or testing procedures required in the UV test for plastic 
tubing. Parker/Atofina stated that the alternate procedures in ASTM G53 
and in SAE J844 are sufficient to display compliance with the current 
SAE J844 specification.
    NHTSA disagrees that manufacturers will have to purchase new 
equipment that has the automatic irradiance control device. The 
requirement for the automatic irradiance control device is added to 
FMVSS No. 106 because the agency believes the device will provide the 
best available control of the UV irradiance level during the testing 
and reduce the likelihood of overexposure to UV light, compared to the 
alternate method of not using automatic irradiance control and rotating 
the lamps every 400 hours, discarding them after 1600 hours, and the 
other specified steps. NHTSA believes inclusion of automatic irradiance 
control will reduce variability in test results.
    NHTSA believes that air brake tubing manufacturers will be able to 
use their existing UV test equipment if they are able to maintain the 
minimum specified irradiance level of 0.85 watts per square

[[Page 76310]]

meter. It is possible that equipment without irradiance measurement and 
control would result in higher irradiance levels and thus be more 
severe than the agency's required UV exposure requirement.
    SMC commented that in the NPRM's section on Rulemaking Analyses and 
Notices, the capital cost to purchase a new ultraviolet test apparatus 
should be taken into consideration. SMC cited Executive Order 12866 for 
its position. In the NPRM, NHTSA discussed the cost issues resulting 
from the brake hose rulemaking and estimated the cost of upgrading 
brake hoses to meet with proposals in the NPRM to be in the range of 
zero dollars to $1.6 million annually. Further, the agency stated that 
it did not believe that the rulemaking would have a significant 
economic impact on a substantial number of small entities. Regarding 
SMC's comments on the cost of purchasing new test equipment, NHTSA 
believes that the cost of such equipment may be on the order of $5,000 
to $10,000, a sum that would not have a significant effect on NHTSA's 
estimated cost of this rulemaking.
    Parker/Atofina stated that it believes NHTSA's proposed inclusion 
of ASTM D4329-99 and G 151-97 offer education to the reader, but do not 
add significantly to the testing procedure or to the requirements 
specified in SAE J844. Parker/Atofina recommended that references to 
ASTM G 53, as referenced in SAE J844, are sufficient. As NHTSA noted in 
the NPRM, G 53 has been replaced by G 154. NHTSA believes that it 
should reference the most current of these two ASTM standards, since a 
goal of the agency's rulemaking is to update FMVSS No. 106 and remove 
obsolete references.
    The NPRM referred to three ASTM standards: G 154-00, which provides 
information on the spectral output of the UVA-340 lamps; G 151-97, 
which provides practices to maintain control of irradiance within a 
test device; and D 4329-99, which provides guidance on preparation of 
test samples, positioning in the test device, and interpreting test 
results. NHTSA believes that because these three ASTM standards are 
interrelated, they should all be included in FMVSS No. 106. Therefore, 
in the final rule, the agency is keeping references to all three ASTM 
standards.
    ASTM commented that the latest revision of ASTM standard G 151 
Standard Practice for Exposing Nonmetallic Materials in Accelerated 
Test Devices that Use Laboratory Light Sources was G 151-00. NHTSA 
agrees that ASTM G 151-00 is the latest revision and probatively tests 
plastic tubing for ultraviolet resistance. In this final rule, NHTSA is 
incorporating ASTM G 151-00 in S12.7 Ultraviolet light resistance test.
9. Resistance to Zinc Chloride and Methyl Alcohol
    NPRM--NHTSA proposed to incorporate the zinc chloride and methyl 
alcohol resistance requirements and test procedures from SAE J844 into 
FMVSS No. 106.
    Public Comments and NHTSA's Response--DuPont stated that the 
agency's proposed test proposal was marginally adequate for FMVSS No. 
106. It suggested considering adopting the requirements of ISO 7628 at 
S7.9.2, that includes resistance testing to zinc chloride, copper 
chloride, sodium chloride, and potassium chloride. In addition, testing 
discrete samples of brake tubing may be appropriate to evaluate all 
layers of the tubing, as may be found with cut ends of tubing or if an 
outer layer of the tubing is compromised. SGPPL also referenced the 
test in ISO 7628 and suggested that the agency may wish to review the 
test requirements. SGPPL stated that SAE is currently reviewing the ISO 
7628 requirements and the ISO 7628 test may be needed, given the 
various chemicals used on roads today.
    SGPPL requested a clarification that in the agency's proposed zinc 
chloride test, only the outside of the tubing is to be exposed during 
the test. SGPPL stated that the outside is the only part of the tubing 
that is exposed to zinc chloride while in operation on a motor vehicle. 
NHTSA agrees with this comment, and provides additional text in the 
final rule to clarify that the zinc chloride test is only conducted on 
the exterior of the tubing.
    Regarding the incorporation of additional chemical resistance tests 
into FMVSS No. 106, the agency does not have sufficient information to 
include such incorporation in the final rule. NHTSA would also provide 
the public with an opportunity for comment before adopting additional 
chemical resistance tests.
    HPP stated that the bend radius for the zinc chloride and methyl 
alcohol resistance tests (and also the high temperature flexibility 
tests) should be the test bend radius as specified in Table 2 of SAE 
J844, rather than two times the nominal outside diameter of the tubing 
as specified in the NPRM. This was also noted by Parker/Atofina. NHTSA 
has concluded that the commenters are correct and for the zinc 
chloride, methyl alcohol resistance, and high temperature flexibility 
tests, is referencing the bend radii from FMVSS No. 106's Table VIII in 
the final rule.
10. Stiffness
    NPRM--Because FMVSS No. 106 does not contain a similar set of 
procedures/requirements, NHTSA proposed to incorporate the stiffness 
procedures/requirements from SAE J844 into FMVSS No. 106. The stiffness 
test requires that a section of tubing is conditioned in a straight 
position at 230 degrees Fahrenheit for 24 hours, and after cooling and 
by using a special test fixture, the force required to deflect the 
tubing 2 inches at its ends is measured. The resulting force may not 
exceed a specified amount that ranges between one pound and 80 pounds 
depending on the diameter of the tubing. In the NPRM, the agency stated 
its belief that this test would ensure that the flexibility of the 
tubing is not reduced when the tubing is subjected to elevated 
temperatures.
    Public Comments and NHTSA Response--SGPPL commented that it sees 
reasons to both include and exclude this test requirement from FMVSS 
No. 106. It believes that the stiffness test is not a true performance 
criterion for the tubing, and that stiffness is not linked to any 
failure mode. Stiffness also does not gauge form, fit, or function of 
the product. Historically, thermoplastic air brake tubing has replaced 
traditional steel and copper tubing air lines, and although much less 
stiff, plastic tubing stiffness does not affect the end functionality 
of the tubing. SGPPL stated that this test could be considered design 
restrictive and written around the use of plasticized polyamide 
material. SGPPL stated that the stiffness test does serve a purpose 
from the perspective of a truck original equipment manufacturer (OEM) 
in that overly stiff tubing would be too difficult to route during 
truck assembly.
    SGPPL noted that the stiffness test as proposed in the NPRM did not 
include a pull rate specification that can affect the results of the 
test. It stated that it consistently uses a pull rate of one inch per 
minute.
    NHTSA has considered SPPL's comments and agrees that it would be 
difficult to identify how failures of the stiffness test would be 
detrimental to motor vehicle safety. The agency agrees that the 
stiffness test may serve a purpose for vehicle manufacturers that 
desire to specify a particular stiffness in their specifications for 
its airbrake tubing. NHTSA also believes that specific stiffness 
characteristics may be desirable for tubing used in applications such 
as when long runs of tubing are used on semitrailers versus tubing used

[[Page 76311]]

to plumb tractors. Therefore, NHTSA is not including the stiffness test 
in this final rule. In lieu of the stiffness test, NHTSA specifies a 
test for collapse resistance as a measure of brake tubing performance 
when subjected to elevated temperatures.
11. Heat Aging Adhesion
    NPRM--NHTSA proposed to incorporate the heat aging adhesion test 
procedures from SAE J844. NHTSA also proposed that the minimum adhesion 
performance requirement for Type B tubing be changed from the SAE 
requirement of ``no separation'' to 25 pounds per linear inch. NHTSA 
described several problems in directly applying the SAE J844 
requirements. Foremost is that during the adhesion test, in which air 
brake tubing made of two layers is separated at the layer interface by 
cutting it apart and then subject to being pulled apart at this 
juncture, SAE J844 states that no separation at the layer interface is 
permitted. NHTSA pointed out that this could not be adopted because the 
tubing will ultimately fail at some point during the test. NHTSA 
proposed a metric of 25 pounds minimum separation force per linear 
inch, based in part on a similar test that is contained in FMVSS No. 
106 to measure the layer separation performance of elastomeric air 
brake hoses.
    The agency proposed that rather than having a stand-alone adhesion 
test, the adhesion test would only be performed as specified in SAE 
J844 that includes a heat aging conditioning test. This would eliminate 
the need to run an adhesion test, and also a heat aging and adhesion 
test.
    The agency also deviated from SAE J844 in that rather than 
preparing a test sample from a helical section of hose, with the cut 
line following one of the reinforcing braids in the tubing, NHTSA 
proposed that the sample be prepared from an inch-long sample of tubing 
cut through one side along its longitudinal centerline.
    Public Comments and NHTSA's Response--SMC commented that the 
agency's proposal to include a process that generates numerical data is 
superior to what it used in SAE J844. SAE noted that the separation 
requirement for elastomeric air brake hose is 8 pounds per linear inch, 
and stated that the separation requirement in SAE J2547 (a draft 
document in committee) is 4.4 pounds per linear inch. SMC stated that 
the reason that air brake tubing layers would separate would be 
relative motion between the connections (end fittings). NHTSA notes 
that plastic air brake tubing is used in applications that involve 
relative motion between components (e.g., the connections between 
tractors and trailers), but in those applications the tubing is in 
coiled form that generally distributes torsional and bending stresses 
over a great length of tubing. SMC also stated that the method of 
performing adhesion testing in SAE J2547 is still being drafted, and it 
did not provide any details as to what it might include.
    DuPont stated that it agrees with the agency's proposed adhesion 
strength of 25 pounds per linear inch. It also stated that it believed 
the adhesion test to be potentially redundant since the performance in 
both the low temperature impact and heat age burst pressure tests would 
presuppose adequate bond strength.
    SGPPL wrote in favor of adopting the 25 pounds per linear inch bond 
strength. It noted the difference between the sample preparation in SAE 
J844 which requires the cutting of a strip of tubing into a 6 
millimeter wide helical coil (and other requirements) versus the NPRM 
proposal to cut a one-inch length of tubing cut lengthwise and cutting 
two flaps of material using a sharp knife to permit the test sample to 
be clamped in a tensile testing machine. SGPPL noted that if what is 
now a Type B tubing consisting of two layers were made as a single 
layer tubing, the bond strength test might not be needed. In addition, 
it posed the questions that if tubing were to be manufactured from 
several layers of different material bonded together, how would the 
adhesion levels be evaluated, and would it only be required at the bond 
interface of reinforcing material? SGPPL stated that it would be even 
more difficult to test between unreinforced layers of plastic than 
between a reinforced inner and outer layer.
    HPP stated that there is no technical reason for a higher 
requirement for plastic tubing compared to elastomeric hoses. HPP has 
developed a method to determine the adhesion between layers of tubing, 
and references a ballot version of SAE J2260. However, HPP did not 
describe their test method, nor did it provide any further information 
about SAE J2260 that the agency could evaluate.
    Parker/Atofina stated that the performance strength of Type B 
tubing is historically predicated on maintaining an inseparable bond 
between polymer layers across the yarn reinforcement interstitial areas 
within the tubing. Permitted separation between these tube and cover 
layers at the bond interface will result in tubing which kinks easily 
under mechanical stress. It states that the agency's proposal of 25 
pounds per linear inch is insufficient to ensure consistent plastic 
tubing and assembly performance. According to Parker/Atofina, the SAE 
J844-mandated inseparable bond test is intended to evaluate the 
integrity and manufactured quality of the Type B thermoplastic air 
brake tubing construction.
    Regarding the agency's proposed test sample preparation method, 
Parker/Atofina stated that the preparation of an inch-long specimen is 
impractical and impossible with properly manufactured and inseparably 
bonded Type B tubing. It stated that the test sample must be cut 
through the entire tubing wall in a helical path nearly parallel to the 
reinforcement yarn lay pattern in order to gain access to the layer 
interface and allow physical and visual evaluation of the bond between 
the polyamide layers in the interstitial areas formed away from where 
the yarn lay patterns cross. The agency notes by examination of a 
typical \1/2\ inch O.D. Type B air brake tube, the sample size defined 
in SAE J844 for this size tubing would be 0.25 inches by 7.85 inches. 
The agency does not know if this sample size would be large enough to 
mount in a tensile testing machine for evaluation. Under the agency's 
NPRM, the sample size would be approximately 1 inch by 1\1/2\ inches 
for \1/2\ inch O.D. air brake tubing.
    Parker/Atofina stated that the SAE J844 adhesion test does not 
require a force measurement because the criterion for passing is an 
intimate bond as if the two layers were one. The need to specify a load 
is replaced by the visual examination between the two layers of 
contrasting colors.
    The agency has reviewed all of the comments regarding adhesion 
testing and decided not to include the heat aging and adhesion test 
requirement in the final rule. It appears that the actual strength of 
the bond between layers of plastic tubing falls somewhere between 4.4 
pounds per linear inch and something larger than 25 pounds per linear 
inch. The agency's proposed test method seemed acceptable to some 
commenters, but there were wide ranging viewpoints on what the 
acceptable adhesion strength should be. The SAE J844 test method 
appears unenforceable to NHTSA because it does not have any objective 
pass/fail metrics, such as a pounds force per linear inch strength 
requirement. The ``no separation'' specification in SAE J844, confirmed 
by visual inspection and not by a force measurement, does not seem to 
be a useful metric to determine the strength of the bond between tubing 
layers. In addition, as noted by SGPPL, alternate methods for

[[Page 76312]]

producing air brake tubing may include significantly different 
construction methods (more than two layers, or constructed without 
reinforcing braid) that would not be able to be easily tested to the 
procedure in SAE J844. It appears to NHTSA that the SAE committee 
working on SAE J2547 may be able to develop an alternate adhesion test 
method that the agency may be able to consider using in future 
rulemaking.
12. Collapse Resistance
    NPRM--NHTSA proposed to incorporate the collapse resistance test 
procedures/performance requirements from SAE J844 into FMVSS No. 106, 
with two changes. First, the length of the pins that are used to attach 
the tubing in a bent position to the test fixture were specified as 1-
inch or 50 millimeters in length, rather than left unspecified as in 
SAE J844. Second, the bend radii from Table 2 of SAE J844 were proposed 
to be adopted rather than the bend radii from SAE J844 Table 3, in 
order to have just one table of bend radii in FMVSS No. 106. The 
differences in the radii tables are slight, for example, for a \1/2\ 
inch O.D. tube, Table 2 specified 2.00 inches versus 2.50 inches in 
Table 3, although for some other sizes of tubing, the radii in the two 
tables are the same. This made the proposal in FMVSS No. 106 slightly 
more rigorous than SAE J844, because in the collapse resistance test 
the tubing is bent without being supported by a test cylinder, and the 
bend radii in Table 2 are for bends that use a test cylinder for 
support as the tubing is bent around the cylinder.
    Public Comments and NHTSA's Response--SMC stated that it find the 
agency's proposal acceptable. Parker/Atofina stated that the tubing 
sample length formulas specified in FMVSS No. 106 at S12.17(b) are less 
severe than in SAE J844. The diameter measurements in SAE J844 to 
validate the collapse resistance of tubing have been replaced with 
nominal diameters, lessening the severity of the bend test. NHTSA has 
carefully compared the requirements in SAE J844 with the NPRM, and 
cannot verify Parker/Atofina's statements. The diameter collapse 
measurement procedures proposed in Standard No. 106 at S12.15(c) 
Calculation are in fact the same calculation as used in SAE J844 at 
S9.14.5, and do not refer to a nominal diameter specification. The 
tubing samples specified in FMVSS No. 106 at S12.15(b) are the same as 
those in SAE J844. However, in FMVSS No. 106, the length of the 
supporting pins is specified while in SAE J844, the length of the 
supporting pins is not specified. For both FMVSS No. 106 and SAE J844, 
the length of the supporting pins is considered in the length of the 
prepared tubing sample. NHTSA used different wording in the NPRM to 
amend FMVSS No. 106 than in SAE J844, partly to better describe the 
test procedure, and to avoid having to adopt Figures 3 and 4 from SAE 
J844 into FMVSS No. 106. NHTSA determined only that the collapse 
resistance proposed in FMVSS No. 106 is slightly more rigorous than in 
SAE J844 because of minor reductions in the bend radii used during the 
evaluation of collapse resistance for a few particular sizes of tubing.
    Parker/Atofina also commented that the minimum kink radii from 
Table 3 of SAE J844 should be used for the collapse resistance test, 
and that Table VIII should be labeled ``minimum kink radius'' rather 
than ``bend radius'' as proposed in the NPRM.
    For this final rule, after reviewing the proposed collapse 
resistance test and the comments provided, NHTSA has decided to amend 
the requirements from those proposed in the NPRM. Table VIII has been 
modified to include both sets of bend radii from SAE J844 (Table 2, 
Mechanical Properties, Test Bend Radius adopted into Table VIII of 
FMVSS No. 106 as ``Supported Bend Radius,'' and Table 3, Minimum Kink 
Radius adopted into Table VIII of FMVSS as ``Unsupported Bend 
Radius.''). The supported bend radius values for metric sizes of brake 
tubing in Table VIII are taken directly from Table 2 in SAE J1394, but 
there are no values provided for Minimum Kink Radius in SAE J1394 that 
can be used for unsupported bend radius values in Table VIII in FMVSS 
No. 106.
    NHTSA used the following approach to determine the unsupported bend 
radius values for metric sizes of air brake tubing for Table VIII:
    1. The nominal diameter of 6 mm tubing is 0.236 inches, and is 
closer to \1/4\ inch tubing (0.250 inches), so the 1.00 inch 
unsupported bend radius for \1/4\ inch tubing was adopted.
    2. The nominal diameter of 8 mm O.D. tubing is 0.315 inches, and is 
close to \5/16\ inch tubing (0.313 inches), so the 1.50 inch 
unsupported bend radius for \5/16\ inch tubing was adopted.
    3. The nominal diameter of 10 mm O.D. tubing is 0.393 inches, and 
is close to \3/8\ inch tubing (0.375 inches), so the 1.50 inch 
unsupported bend radius for \3/8\ inch tubing was adopted.
    4. The nominal diameter of 12 mm O.D. tubing is 0.472 inches, and 
is close to \1/2\ inch tubing (0.500 inches), so the 2.5 inch 
unsupported bend radius for \1/2\ inch tubing was adopted.
    5. The nominal diameter of 16 mm O.D. tubing is 0.629 inches, and 
is close to \5/8\ inch tubing (0.625 inches), so the 3.00 inch 
unsupported bend radius for \5/8\ inch tubing was adopted.
    The agency adopts the term ``unsupported bend radius'' rather than 
Parker/Atofina's recommended ``minimum kink radius'' because during the 
collapse resistance test, the tubing is not permitted to kink. To use 
the term ``kink'' in FMVSS No. 106 may prove to be confusing.
    The regulatory text of the test procedure in S12.15 has been 
modified in three respects from that proposed in the NPRM. First, the 
two supporting pins of the test fixture are not required to be 
adjustable, since pins only need to be set at a specified spacing as 
shown in Figure 5--Bend Test Fixture of SAE J844. The pin spacing 
requirement is now defined as twice the unsupported bend radius plus 
the nominal O.D. of the tubing, consistent with what is depicted in 
Figure 5 of SAE J844. In the NPRM, the pins were to be adjusted until 
the approximate bend radius was achieved on the brake tubing. The 
language in the final rule is simpler and has less opportunity for 
introducing variability. Second, a provision is added that the tubing 
should be bent in the direction of its natural curvature, consistent 
with SAE J844. Third, the term ``elliptical minor diameter'' is used 
rather than ``minor diameter'' to better indicate in geometric 
terminology where the initial and final diameter measurements of the 
tubing are to be taken.
13. Oil resistance
    NPRM--NHTSA tentatively concluded that in the case of plastic air 
brake tubing, it would be more appropriate to evaluate a mechanical 
property of the tubing such as the ability to pass a burst test after 
conditioning in oil. NHTSA also concluded it is critical that plastic 
air brake tubing be resistant to oil exposure. Therefore, NHTSA 
proposed a test procedure for plastic tubing that combines existing 
FMVSS No. 106 oil conditioning criteria with the burst strength 
requirements of SAE J844. The proposed test procedure involved 
preparation of a tubing assembly, conditioning it in ASTM IRM 903 oil 
(which supercedes ASTM No. 3 oil as described in ASTM D471-98e1, 
Standard Test Method for Rubber Property-Effect of Liquids), and then 
subjecting the tubing to the burst test specified in SAE J844. NHTSA 
proposed that the tubing not burst at less than 80 percent of the burst 
pressure listed in Table 2 of SAE J844.
    Public Comments and NHTSA's Response--HPP stated that the proposed 
oil resistance test should apply to

[[Page 76313]]

elatostomeric brake hoses in addition to air brake tubing. SMC stated 
that the burst pressure of SAE J844 is more suited to testing tubing, 
and that the oil needs to be changed to stay consistent with the ASTM 
changes. SGPPL agreed that it is critical that plastic air brake tubing 
is resistant to oil, but stated that it has not performed any such 
testing as proposed in the NPRM. SGPPL asked if both the inner diameter 
and the outer diameter of the tubing were to be submerged in oil, and 
questioned whether the oil resistance requirements would be more 
suitable to brake hose assemblies as described in Section E, Plastic 
Air Brake Tubing Assemblies and End Fittings, of the NPRM. It stated 
that as proposed in the NPRM, it is a tubing material test, rather than 
a test for the mechanical properties of end fittings.
    DuPont agreed with the addition of an oil resistance test to FMVSS 
No. 106. Parker/Atofina asked that its previous comments relating to 
the burst test (water used as the test medium and timing of pressure 
rise be measured) be considered for the oil resistance test as well.
    After reviewing the comments, NHTSA also reviewed the proposed 
requirements for the end fitting retention test in S11.3.23, which was 
adopted from SAE J1131. This test evaluates the retention of end 
fittings that are used with plastic air brake tubing. A sample air 
brake tubing assembly is prepared, filled with hydraulic fluid and then 
pressurized to 50 percent of the burst strength pressure. This pressure 
is held for 30 seconds, and then the pressure is increased to 100 
percent of the burst strength pressure. No leakage or separation is 
permitted.
    The agency also reviewed the proposed thermal conditioning and end 
fitting retention test in S11.3.24 that was proposed to be adopted from 
SAE J1131. In this test, an air brake tubing assembly is prepared with 
end fittings, filled with hydraulic oil, and connected to a source of 
hydraulic pressure. The assembly is then conditioned in air at 200 
degrees Fahrenheit for 25 hours with atmospheric pressure inside the 
tubing. The pressure is then increased to 450 psi while still at the 
elevated temperature, and held for five minutes. The pressure is 
reduced to atmospheric and the temperature reduced to 75 degrees 
Fahrenheit for one hour, and then the temperature is decreased to minus 
40 degrees Fahrenheit for 24 hours. While at that temperature, the 
pressure is increased to 450 psi and held for five minutes, and the 
required performance is that no leakage or separation from the end 
fittings is permitted.
    Parker/Atofina's only recommendation for the thermal conditioning 
and end fitting retention test was to increase the pressure within 5 to 
30 seconds during the pressure cycles to not hydraulically shock the 
system.
    NHTSA evaluated all of the comments, reviewed the proposed test 
requirements, and reached the following conclusions. NHTSA has 
determined that the oil resistance test is intended to evaluate the 
properties of the tubing (S11.3.18 specifies that the air brake tubing 
shall not rupture or burst) although it may also evaluate the oil 
resistance properties of the end fittings, since end fittings must be 
installed to attach the tubing to the pressure test machine. Whether 
those end fittings are the same as the end fittings used on a vehicle, 
or are fittings designed to adapt the tubing to the pressure test 
device, is a decision to be made by the test sponsor. Both oil and 
water are non-compressible and will provide the same measure of 
performance. Therefore, the oil resistance test will be made final in 
this rule, but the pressure test medium (after the conditioning by 
soaking in oil) can be either water as suggested by Parker/Atofina for 
the final burst test, or oil at the manufacturer's option if cross-
contamination of the water pressure source for the burst testing 
specified in S12.5 is a concern of the manufacturer.
    The thermal conditioning and end fitting retention test is kept in 
the final rule for the purpose of evaluating end fitting retention when 
subject to thermal and pressure cycling. Water cannot be used in the 
thermal conditioning and end fitting retention test because of the low 
temperatures (minus 40 degrees Fahrenheit (minus 40 degrees Celsius)) 
involved. NHTSA noted in the NPRM that the hydraulic fluid in SAE J1131 
did not have any particular specifications. NHTSA believes that if it 
changed the specification in the thermal conditioning and end fitting 
retention test to the ASTM IRM 903 oil, the test would be more suited 
towards ensuring that the end fitting retention test also provides a 
measure of oil resistance as well. The conditioning at 200 degrees 
Fahrenheit for 70 hours is similar to the requirements proposed for the 
oil resistance test except that a slightly higher oil soak temperature 
of 212 degrees Fahrenheit was proposed for the oil resistance test.
    NHTSA adopts a constant pressure application and reduction rate of 
3,000 psi per minute for all burst tests and pressure increases or 
decreases, to eliminate variability in the time of the pressure 
application. NHTSA believes it has thus addressed Parker/Atofina's 
suggestion of a longer time limit for the pressure increases in the 
thermal conditioning and end fitting retention test.
    NHTSA believes that with these changes, the plastic air brake 
tubing material and the end fittings of tubing assemblies will be able 
to be evaluated for oil resistance. NHTSA believes that both the 
outside and inside sections of brake hose tubing should be oil 
resistant, and includes this requirement in the oil resistance test. 
The thermal conditioning and end fitting test will only evaluate the 
oil resistance of those portions of the end fittings that are exposed 
to internal pressure in the tubing.
    Finally, NHTSA notes that it may revisit the issue of the oil 
resistance test in a future rulemaking if this should become necessary.
    NHTSA proposed that ASTM IRM 903 be the test medium for gauging air 
brake tubing and assemblies for oil resistance properties. NHTSA has 
reviewed the oil compatibility test in S3.7 of SAE J2494-3 Performance 
Requirements for SAE J844 Non-Metallic Air Brake Tubing and Push-to-
Connect Tube Fittings, with SAE J844 Air Brake Tubing as Used in 
Vehicular Air Brake Systems, (described in more detail below), and 
notes that it is conducted using a mixture of 11 parts SAE 15W40CD type 
oil and one part SOFTC-2A contaminant. No commenter made note of this 
different reference oil specification. NHTSA is therefore keeping the 
ASTM oil specification in this final rule.
    Regarding the end fitting retention test that was proposed as 
S12.24 in the NPRM (designated as S12.22 in this final rule), NHTSA is 
adopting Parker/Atofina's suggestion that water be used as the test 
medium rather than oil. Parker/Atofina stated that water is a cleaner 
test medium than hydraulic oil, and the agency believes that there are 
no special temperature requirements that preclude the use of water in 
this test. The pressure increase rate is being specified as 3,000 psi 
per minute as it is for all other test requirements relating to 
pressure tests for air brake tubing.
    NHTSA is not adopting HPP's suggestion to subject elastomeric air 
brake hoses to the oil resistance test in this final rule. NHTSA notes 
that these types of brake hoses are subjected to a different type of 
oil resistance performance test that appears to be effective in 
ensuring adequate safety of these brake hoses.

[[Page 76314]]

14. Ozone resistance
    NPRM--NHTSA proposed an ozone test for plastic air brake tubing in 
which a sample of tubing is bent around a test cylinder and exposed to 
ozone at a concentration of 100 parts ozone per hundred million parts 
of air, for 70 hours at a temperature of 104 degrees Fahrenheit. The 
required performance is that no cracks are visible when the tubing is 
viewed under 7x magnification.
    Public Comments and NHTSA's Response--Parker/Atofina stated that 
thermoplastic air brake tubing does not require ozone testing because 
polyamide nylon is not affected by ozone. HPP stated that it supports 
the ozone test for plastic tubing, but it recommended that for tubing 
used with barbed end fittings, a test of the tubing with the end 
fittings attached should be conducted with a longer exposure time of 
500 hours. DuPont acknowledged the importance of having an ozone 
resistance test in FMVSS No. 106. Several commenters noted that the 
agency had incorrectly stated the proposed ozone concentration in parts 
per million rather than parts per hundred million (pphm). The correct 
ozone concentration level of 100 pphm is included in this final rule.
    NHTSA notes that for all types of brake hoses in FMVSS No. 106, the 
ozone concentration is being increased from 50 to 100 pphm in 
accordance with the latest SAE standards. As such, this represents an 
increase in the severity of the test condition. NHTSA does not believe 
that it would be appropriate to increase the exposure time from 70 to 
500 hours at this time, as recommended by HPP. NHTSA believes that 
there is little or no use of barbed hose fittings on air braked 
vehicles in the United States, as the most common styles are push-to-
connect and flanged sleeve compression fittings.

F. Plastic Air Brake Tubing Assemblies and End Fittings

1. General Comments
    In the NPRM, NHTSA proposed to incorporate the substantive 
requirements of SAE J1131 Performance Requirements for SAE J844 
Nonmetallic Tubing and Fitting Assemblies Used in Automotive Air Brake 
Systems into FMVSS No. 106. NHTSA noted that the petitioners did not 
ask NHTSA to adopt the requirements of this SAE standard into FMVSS No. 
106. The petitioners had instead asked that NHTSA adopt the 
requirements of SAE J512 Automotive Tube Fittings and SAE J246 
Spherical and Flanged Sleeve (Compression) Tube Fittings. These two 
latter standards include specific dimensional requirements for the end 
fittings and components of fittings. The agency tentatively determined 
that rather than specifying the dimensions of the fittings, it would be 
more appropriate to specify the performance of the fittings per SAE 
J1131, to assure that the end fittings used along with air brake tubing 
work properly as an assembly.
    Parker/Atofina stated that it believes that end fitting 
dimensional, material, performance and safety requirements referenced 
in SAE J246 and SAE J512 specifications should be retained, so that the 
components of end fittings from different manufacturers would continue 
to be compatible. As stated in the NPRM, the agency does not desire to 
include these dimensional specifications (which are in effect design 
specifications), but proposed instead to adopt the performance 
requirements for these fittings when used with plastic air brake 
tubing.
    SMC, SGPPL, and Parker/Atofina made reference to three SAE 
Standards: J2494-1 Push-to-Connect Tube Fittings for Use in the Piping 
of Vehicular Air Brake, Rev. May 2000; J2494-2 Dimensional 
Specifications for Non-Metallic Body Push-to-Connect Fittings Used on a 
Vehicular Air Brake System, Rev. October 2002; and J2494-3 Performance 
Requirements for SAE J844 Non-Metallic Air Brake Tubing and Push-to-
Connect Fitting Assemblies Used in Vehicular Air Brake Systems, Rev. 
July 2002. SMC stated that incorporation of SAE J2494-3 would benefit 
the evaluation of the FMVSS No. 106 revision. SGPPL stated that since 
push-to-connect fittings are widely used in both preformed air brake 
tubing assemblies and in routing bulk air brake tubing lines in trucks, 
NHTSA should consider the use of both push-to-connect and compression 
fittings. Parker/Atofina recommended that FMVSS No. 106 include the 
sample size requirements of SAE J2494-3 and the performance 
requirements of SAE J1131. Regarding Parker/Atofina's issue with sample 
sizes for testing, the agency has already described that sampling as an 
issue for manufacturers to use for quality control methods, but that 
every brake hose that is DOT certified must meet the requirements of 
FMVSS No. 106.
    The agency was not aware of the SAE J2494 series of standards for 
push-to-connect fittings when it published its NPRM. After reviewing 
these standards, NHTSA believes that adding the substantive end fitting 
performance requirements of SAE J2494-3 to FMVSS No. 106 would help 
ensure safety. However, NHTSA notes that incorporating SAE J2494-3 
requirements into FMVSS would encompass an extensive series of test 
procedures including a tensile test (with high temperature, boiling 
water, and water absorption conditioning); thermal and pressure cycling 
and air leakage; vibration test; fitting pressure test; frozen water 
retention test; reassembly test; oil compatibility test; corrosion 
resistance test; side load leakage; moisture absorption; ultraviolet 
light resistance; zinc chloride and methyl alcohol resistance; and cold 
temperature impact. NHTSA would not issue a final rule amending FMVSS 
No. 106 by incorporating these tests without first putting forth a 
notice soliciting public comments on its proposal to include the tests. 
Some of the performance requirements included in the NPRM and this 
final rule provide similar coverage of the SAE J2494 requirements. 
Therefore, NHTSA will first complete its May 15, 2003 proposed 
rulemaking by issuing this final rule. At future date, NHTSA may 
consider proposing to add the outstanding requirements from SAE J2494.
2. Tensile Strength
    NPRM--NHTSA proposed adopting similar tensile strength requirements 
for plastic air brake tubing as FMVSS No. 106 currently specifies for 
elastomeric air brake hose. The NPRM included slight reductions in 
tensile strength for the smallest sizes of plastic air brake tubing, 
proposing 35 pounds for \1/8\ inch and 40 pounds for \5/32\ inch 
tubing, in applications that are not between the frame and axle of a 
vehicle or between a towing and towed vehicle. The lowest specification 
for elastomeric brake hoses in the same application is 50 pounds if it 
is \1/4\ inch or less nominal inside diameter.
    NHTSA developed its proposed requirements for small diameters of 
plastic air brake tubing based in part on a comparison of brake hose 
and tubing. Air brake tubing is sized by outside diameter rather than 
inside diameter (as brake hose is sized), and therefore, the sizes are 
not directly comparable. A \1/4\ inch outside diameter brake tube would 
be smaller than a \1/4\ inch inside diameter brake hose, and therefore 
would not be expected to have the same tensile strength.
    NHTSA noted that in the text on page 26403 of the NPRM that it 
correctly stated its intentions of a 35-pound strength for \1/8\ inch 
tubing and 40 pounds for \3/32\ inch tubing. However, Table VIII on 
page 26417 included incorrect values of 15 pounds for \1/8\ inch tubing 
(which should have been 35

[[Page 76315]]

pounds) and of 40 pounds for \3/16\ inch tubing (it should have been 50 
pounds). These are corrected in the final rule. The values in Table 
VIII for \3/32\ inch tubing were correct in the NPRM.
    Public Comments and NHTSA's Response--SGPPL stated in its comments 
that it agrees with NHTSA's proposed reduction in tensile strength for 
\1/8\ inch and \5/32\ inch tubing. SGPPL stated that the 50-pound value 
used by SAE for \1/8\ inch tubing and \5/32\ inch tubing are not 
achievable using current products in the market place, as the tubing 
yields and breaks before a 50-pound value is attained in testing. SGPPL 
stated that the proposed values of 35 pounds and 40 pounds respectively 
are achievable using current tubing constructions.
    SMC stated that the values in SAE J1131 (15 pounds for \1/8\ inch, 
40 pounds for \5/32\ inch) reflect the tensile strength of current 
tubing material, and that higher values in SAE J2494 (50 pounds for \3/
32\ through \1/4\ inch) is intended to meet the requirements are 
currently stated in FMVSS No. 106 and may be higher than the 
application requires and also may be design restrictive. SMC stated 
that the agency's proposal for reduced tensile strength requirements 
reflects the current capability of nylon tubing. However, NHTSA notes 
that SMC shows in its table of tensile strength the incorrect values 
that were included in the NPRM (15 pounds for \1/8\ inch and 40 pounds 
for \3/16\ inch). SMC also noted another error in Table VIII of the 
NPRM, where the correct tensile strength values for \3/8\ inch tubing 
should be 667 N or 150 pounds. The correct values are stated in the 
final rule.
    Parker/Atofina stated that the present plastic tubing sizes and 
constructions specified in SAE J844 can meet the tensile strength 
requirements in FMVSS No. 106 and it did not see a basis for lowering 
these requirements. Parker/Atofina also asserted that the agency 
provided no engineering basis for its decision. NHTSA notes that it 
described in detail the reasons for lowering the tensile strength 
requirements for small diameters of tubing, including the fact that 
small diameters of air brake tubing are smaller than equivalent sizes 
of elastomeric air brake hose. Parker/Atofina did not describe how it 
views the requirements in SAE J1131, where the tensile strength 
requirements are specified for tubing assemblies that are lower than 
the values that NHTSA proposed in the preamble of the NPRM.
    Based on the available information and comments received, NHTSA 
believes that the proposed tensile strength values for small diameters 
of plastic air brake tubing are attainable by current plastic air brake 
tubing and therefore will incorporate these tensile strength values in 
this final rule.
    Several commenters indicated that the proposed regulatory text for 
the plastic air brake tubing in S12.20 incorrectly referred to the 
procedure in S6.9 Dynamic Ozone Test instead of S6.4 Tensile Strength 
Test. The correct procedure is referred to in this final rule, except 
that the tensile strength test procedure for air brake hoses in S8.9 is 
referenced (S6.4 is for testing hydraulic brake hose) since it only 
includes a slow-pull test. SMC commented that the fixtures for holding 
the test specimen should be arranged so that the tubing and fittings 
have a straight centerline corresponding to the direction of the 
machine pull, and that the fitting should be mounted in the test 
machine using the same method as is used to mount the fitting on a 
vehicle. SMC suggested that non-threaded fittings would need further 
evaluation. NHTSA is adding a provision to S8.9 to include that a 
tubing assembly (or air brake hose) is to be arranged in a straight 
line when installed on the tension testing machine.
    Parker/Atofina stated that it would be difficult to conduct the 
tensile test on coiled air brake tubing with the fixtures and 
procedures specified in SAE J1131 and proposed for FMVSS No. 106. 
Parker/Atofina requested that coiled air brake tubing be exempted from 
tensile testing requirements. As NHTSA stated in the NPRM, coiled air 
lines are commonly used for the connections between tractors and 
trailers, and normally function so that tensile loads on them are 
spread out over the long length of the coiled tubing. However, these 
coiled lines can get tangled among themselves, among various components 
(springs and poles) that are used to support the lines above the truck 
frame, or with the electrical cable. Further, NHTSA noted that these 
air lines are completely exposed to the elements, are frequently 
connected and disconnected, and may be subjected to various amounts of 
stretching depending on the physical dimensions of the trailers that 
are towed. The agency does not believe therefore that these air brake 
tubing assemblies should be exempted from tensile strength 
requirements. The tensile tests evaluate the connection of the plastic 
air brake tubing to the end fitting, and these portions of a coiled 
assembly can be evaluated by cutting off each end to a short length and 
testing each of these samples to the tensile strength requirements. 
Also, FMVSS No. 106 allows test samples to be made for such 
evaluations, by using the actual end fittings from the coiled assembly 
coupled to a straight section of air brake tubing if a coiled section 
of tubing cannot be easily straightened to fit on the test machine. The 
end fittings are to be attached according to the end fitting 
manufacturer's instructions. NHTSA assumes that both coiled and 
straight air brake tubing have the same dimensional specifications and 
would perform similarly at the point of connection to the end fittings.
3. Hot tensile strength
    NPRM--NHTSA proposed that the hot tensile strength requirement from 
SAE J1131 be incorporated into FMVSS No. 106. Considering that SAE 
J1131 does not include tensile loads for metric sized plastic brake 
tubing, however, the agency proposed to specify tensile load values for 
metric sized plastic brake tubing.
    Public Comments and NHTSA's Response--Many of the comments 
regarding unconditioned tensile strength discussed in the above section 
``Tensile Strength,'' also apply to this test requirement. The agency 
is adopting the corrected, proposed tensile strength requirements in 
Table VIII of FMVSS No. 106 in this final rule.
    SMC commented that a straight pull should be indicated as in the 
section on ``Tensile Strength.'' NHTSA agrees. In this final rule, 
NHTSA adds the provision on straight pull to the regulatory text.
    SGPPL stated that the test conditions in SAE J1131, upon which the 
agency based its proposal, may be inadequately defined. SGPPL stated 
that variations in hot tensile test results may be introduced by the 
vessel size and rate of boiling water evaporation, and the agency 
should consider more stringently-specified variables such as air flow 
over the exposed length of tubing. Further, it would want to review any 
proposed values for metric-sized plastic tubing before they are 
incorporated into FMVSS No. 106. The agency agrees that there could be 
very slight variations since the heat application rate, type of vessel, 
and other variables are not specified, but in general NHTSA believes 
the variables would not affect the test results since water will boil 
at 212 degrees Fahrenheit (100 degrees Celsius) at standard atmospheric 
pressure, and cannot get hotter. NHTSA believes that as a minimum 
performance test, the vessel must be large enough so that at all times, 
four inches of tubing is submerged, as the water is brought to a boil 
and during the five minutes of conditioning at the boiling point. As to 
the rate of heating the water, the agency believes that the amount of 
heat and the

[[Page 76316]]

method of applying the heat must be considered so that the water is 
brought to a boil without excessively heating the end fitting of the 
brake tubing assembly placed in the vessel. Therefore, in the final 
rule, when NHTSA performs the test, it will bring the water to a boil 
without the brake hose in place. The hose is placed after the water 
comes to a boil.
    NHTSA reviewed the changes between the March 1997 and August 1998 
revisions of SAE J1131 and notes that in the March 1997 revision, the 
water is brought to a boil and then allowed to continue boiling for 
five minutes. In the August 1998 revision, it is stated that the tubing 
is placed in the boiling water for 5 minutes. In the final rule, NHTSA 
is changing the regulatory text so that the water is first brought to a 
boil and then the tubing assembly is placed in it. Placing the tubing 
assembly after the water is brought to a boil will minimize the heating 
of the end fitting during the time the water is brought up to boil, but 
will require a rapid method of connecting the brake tubing assembly to 
the tensile testing machine while the water is boiling. Presumably, 
this would not be too difficult. The heat input required, mass of the 
vessel, and other variables must be at a minimum sufficient to keep the 
water boiling as the tubing assembly is placed in the water, and as it 
is conditioned for five minutes in the water.
    Parker/Atofina stated that the hot tensile strength requirements 
for metric plastic air brake tubing must be consistent with those 
proposed by SAE in revisions of SAE J1394. However, Parker/Atofina does 
not indicate what those values are, as the agency finds that the 
tensile strength requirements are in SAE J1131 and not SAE J1394 or SAE 
J844. SAE J1131 does not include metric sizes of air brake tubing and 
therefore there is no specified tensile strength for these sizes. In a 
previous comment, Parker/Atofina stated, concerning tensile strength 
requirements, that the present plastic tubing sizes specified in SAE 
J844 and SAE J1394 can meet the tensile strength requirements specified 
in FMVSS No. 106. In the absence of any information to the contrary, in 
this final rule, NHTSA is keeping the proposed tensile strength values 
in FMVSS No. 106 Table VIII.
    Parker/Atofina stated that the correct column heading for the 
tensile strength values should be ``conditioned tensile load'' to 
prevent confusion with the tensile strength requirements in S11.3.19. 
NHTSA agrees, and has made this change in the final rule.
    NHTSA's proposed description of measuring free length at the end 
fittings for air brake tubing assemblies (in several tests for air 
brake tubing) was: ``The free length is measured from the innermost 
crimp, ferrule, taper, or other mechanical joint that secures the 
fitting to the tubing and spring guards and other appurtenances are 
disregarded for measurement purposes.''
    Parker/Atofina recommended that ``free length'' be defined simply 
as the exposed tubing between two end fittings. NHTSA has considered 
this change and agrees that the simpler definition would suffice. This 
final rule includes the simplified definition in the regulatory text of 
FMVSS No. 106 for all free length measurements of plastic air brake 
tubing assemblies.
4. Vibration Leak Test
    NPRM--NHTSA stated its belief that the SAE J1131 performance 
requirements/test procedures ensure adequate end fitting performance to 
resist vibration and temperature cycling. NHTSA proposed to adopt the 
requirements from SAE J1131 in which an 18-inch long brake hose 
assembly is subjected to 1,000,000 vibration cycles while being 
thermally cycled between 220 degrees Fahrenheit and minus 40 degrees 
Fahrenheit. The low temperature leakage rate just prior to completion 
of the test is not to exceed 50 cubic centimeters per minute, and at 
room temperature, the leakage is not to exceed 25 cubic centimeters per 
minute.
    Public Comments and NHTSA's Response--SGPPL commented that similar 
testing is in SAE J2494 covering push-to-connect fittings and may 
warrant review. SMC commented that the leakage rate in SAE J2494-3 is 7 
cubic centimeters per minute at minus 40 degrees Celsius and 5 cubic 
centimeters per minute at 24 degrees Celsius, and that the vehicle 
manufacturers requested a lower leakage rate to reduce overall system 
leakage.
    NHTSA agrees that while a lower leakage rate would be better for 
air leak reduction on vehicles, it was not aware of the SAE activity on 
J2494. Before adopting lower leakage values, the agency would first 
need to publish them for public comment. Therefore, in this final rule, 
NHTSA is adopting the values as proposed in the NPRM. In the future, 
NHTSA may propose adopting the lower leakage rates, and solicit public 
comment on the lower rates.
5. Proof and Burst Test (End Fitting Retention)
    NPRM--NHTSA proposed to incorporate the proof and burst test from 
SAE J1131 into FMVSS No. 106 so that there will be a specific test to 
evaluate the performance of end fittings used with plastic tubing. 
NHTSA proposed that this test be conducted using water, as this is the 
test fluid used for the burst strength test for air hoses in FMVSS No. 
106. The tubing assembly is pressurized to one-half of burst strength 
pressure and held at that pressure at 30 seconds, and then the pressure 
is increased to burst pressure. The end fitting is not permitted to 
leak or separate from the tubing.
    Public Comments and NHTSA's Response--SGPPL and Parker/Atofina 
noted some discrepancies between the preambular language in the NPRM 
and the proposed regulatory text. These problems have been corrected in 
the final rule, as they have for other burst tests in FMVSS No. 106. 
Water is specified as the test medium, and the regulatory text is 
changed to a constant 3,000 psi per minute pressure increase rate at 
each stage of pressure increase in the test.
    Parker/Atofina notes that a visual inspection for leakage is only 
to be conducted at the one-half burst pressure point as it would not be 
safe to visually inspect the tubing assembly at the full burst 
pressure. Parker/Atofina states that visual inspection of the assembly 
at full burst pressure should not be conducted. In the final rule, 
NHTSA is removing references to visual inspection for the proof and 
burst test and also the thermal conditioning and end fitting retention 
test. The required performance specification continues to remain that 
the assembly shall not rupture.
    SMC stated that common practice is for the proof pressure to be 50 
percent of the burst pressure or 375 psi for end fittings, and the 
agency notes that this is covered in the first pressure hold of the 
proposed proof and burst test. SMC stated that the failure mode of end 
fitting tests is typically in the tubing. An additional test of the 
fitting can be conducted by plugging the tube end and then pressurizing 
the threaded connection to failure or 1,500 psi. However, NHTSA is most 
concerned about the performance of end fittings when they are connected 
to the brake tubing. NHTSA may consider stand-alone pressure tests of 
end fittings in a future rulemaking.
6. Serviceability Test
    NPRM--NHTSA proposed that the serviceability test be included in 
Standard No. 106 for those fittings that use a threaded retaining nut. 
NHTSA proposed to adopt the serviceability test from SAE J1131 in which 
the fitting is assembled and dissembled four times. After a fifth 
reassembly, the fitting is subjected to a 120 psi pressure test. The 
permitted leakage is not to exceed 25

[[Page 76317]]

cubic centimeters per minute when measured with a mass flow meter.
    NHTSA stated its belief that the serviceability test will ensure 
that the fittings can be separated and reused during servicing of brake 
system components with minimal likelihood of leakage upon reassembly. 
NHTSA stated it did not believe the serviceability test could be 
consistently applied to push-to-connect fittings and therefore did not 
propose to include them in the serviceability test.
    Public Comments and NHTSA's Response--SGPPL referenced SAE J2494-3 
requirements for a similar reassembly test for push-to-connect fittings 
contained in S3.6 of that standard. Under those requirements, a push-
to-connect fitting is connected to a section of air brake tubing, and 
then pressurized to 120 psi and held at that pressure for five minutes. 
The assembly is depressurized and disconnected, and the sequence 
repeated. After the sixth assembly and pressurization, the leakage is 
measured with a mass flow meter and is not permitted to exceed 5 cubic 
centimeters per minute. No trimming of the tubing end is permitted 
during the test sequence.
    Parker/Atofina correctly stated that in the NPRM, the test method 
was identified as 12.26, but that the corresponding test requirements 
were not included in S11. The agency notes that although not included 
in S11, the preamble on page 26,404 presented and discussed the 
proposed test requirements that would be adopted from SAE J1131.
    In this final rule, the agency is adopting its original proposal to 
include this test for threaded fittings only. As stated in the NPRM, 
the serviceability test is used to evaluate end fitting performance for 
reusable fittings after repeated assembly and disassembly. No 
specifications for push-to-connect fittings will be specified in the 
serviceability test. The agency believes that push-to-connect fittings 
should be included, but the test procedure for them in SAE J2494 is 
different from the agency's proposal because the tubing assembly is 
pressurized and then depressurized during each reassembly cycle. 
Further, the leakage rates in SAE J2494 are significantly lower than 
those proposed to be adopted from SAE J1131, and NHTSA believes that an 
opportunity for public comment would be needed before adopting the more 
stringent requirement. NHTSA may revisit these issues in a future 
rulemaking.
    No comments were received on the proposed pressure increase time in 
S12.26(c) in which the tubing assembly is pressured to 120 psi in a 
period of two seconds. In the final rule, the agency is specifying the 
pressure increase as 3,000 psi per minute in order to be consistent 
with other performance requirements involving pressure increases for 
air brake tubing. This would yield an elapsed time of 2.4 seconds from 
zero to 120 psi and this is consistent with the 2-second time interval 
that was proposed in the NPRM.
7. End Fitting Dimensional Requirements
    NPRM--NHTSA provided an extensive discussion of why it did not 
propose to incorporate the dimensional requirements for end fittings as 
specified in SAE J246 and SAE J512 into FMVSS No. 106. For example, SAE 
J246 and SAE J512 do not include any metric-sized tubing end fittings 
that the agency could adopt into FMVSS No. 106. Other types of brake 
hoses, including hydraulic, vacuum, and air, do not have end fitting 
dimensional requirements in FMVSS No. 106 and these brake hoses have 
not shown any field problems due to the end fitting dimensional 
specifications. There is also an SAE J246 provision stating that it is 
not intended to restrict or preclude other designs of a tube fitting 
for use with SAE J844 brake tubing. NHTSA tentatively concluded that 
the performance tests for end fittings as specified in SAE J1131 were 
appropriate to adopt into FMVSS No. 106, as various end fittings can be 
used in meeting these requirements.
    Public Comments and NHTSA's Response--Parker/Atofina, whose 
predecessor companies were parties to the petition for rulemaking to 
include these requirements in FMVSS No. 106, stated that the agency's 
proposal not to retain end fitting specifications from SAE J246 and SAE 
J512 creates significant safety issues related to form, fit, function 
and component assembly compatibility. Parker/Atofina stated that 
without the dimensional and geometric requirements defined in those SAE 
standards, end fitting components from one manufacturer will not 
connect, fit and function properly when mated together.
    NHTSA believes that end fitting manufacturers will continue to use 
the SAE standards for end fittings, but is not convinced of the need to 
incorporate them into FMVSS No. 106. NHTSA believes that the minimum 
need to ensure the safety of air brake tubing and assemblies is met 
through adopting the proposed performance specifications and 
dimensional requirements for the tubing so that replacement tubing will 
be compatible with the end fittings. This is what has been done for 
many years for air brake hose. NHTSA is not aware of noted safety 
problems resulting from this practice.
8. End Fitting Corrosion Resistance
    NPRM--NHTSA tentatively concluded that the existing corrosion 
resistance requirements in FMVSS No. 106 assure adequate integrity of 
end fittings, and in one respect is more strenuous than the SAE 
standards. NHTSA proposed to use the existing end-fitting corrosion 
resistance tests in FMVSS No. 106 that includes a 24-hour exposure to 
salt spray in the new section for plastic air brake tubing assemblies. 
NHTSA noted that SAE J246 and SAE J512 specify a longer, 72-hour 
exposure to salt spray for end fittings made from carbon steel, but the 
corrosion resistance test is performed on an end-fitting without 
attaching it to a brake hose. NHTSA proposed to keep the existing 24-
hour exposure and test end fittings as they are attached to the brake 
hose, that is representative of how brake hose assemblies are installed 
on motor vehicles.
    Public Comments and NHTSA's Response--Parker/Atofina stated that it 
agreed with NHTSA's proposal to include the 72-hour duration for the 
salt spray exposure. NHTSA in fact had asked for comments on increasing 
the exposure to 72 hours, but proposed that 24 hours of exposure be 
kept in FMVSS No. 106. Parker/Atofina provided no additional discussion 
on this subject.
    SMC recommended that the corrosion resistance test also apply to 
plastic tubing in addition to the end fitting. NHTSA noted in the 
section discussing zinc chloride and methyl alcohol resistance that it 
may consider additional chemical resistance tests for air brake tubing, 
but it would first need to gather more information in this subject. 
After reviewing the comments, NHTSA is adopting the end fitting 
corrosion resistance test as proposed in the NPRM.

G. New Types of Brake Hose

    The commenters brought to NHTSA's attention the following new types 
of brake hose. New hydraulic brake hose configurations have been 
developed in recent years that deviate from the conventional 
configuration of a length of hose with a fitting at each end. Intertek 
indicated that many brake hose assemblies are made of multiple-part 
sections (e.g., three sections of hose and two sections of metal 
tubing), that make determination of free hose length and conducting the 
whip test difficult. Dana indicated that wire-reinforced hydraulic

[[Page 76318]]

brake hose is being used on leisure vehicles, motorcycles, and as a 
performance option for light vehicles and as an aftermarket product, 
and stated that it might be best to provide a separate section in FMVSS 
No. 106 for wire-reinforced hydraulic brake hose. Intertek noted that 
stainless steel braided brake hoses have properties that differ 
significantly from traditional synthetic rubber brake hoses. HPP 
indicated that plastic vacuum brake booster lines are being used, in 
lieu of traditional rubber vacuum brake hose, and recommended that a 
suitable industry standard be developed in cooperation with end users 
and tubing suppliers.
    NHTSA agrees that new developments in brake hoses may warrant 
additional consideration for FMVSS No. 106 rulemaking. However, NHTSA 
believes it is appropriate to first complete the initial updating of 
FMVSS No. 106 before considering further upgrades.

H. Metallic Tubing and Pipe

    Parker/Atofina recommended that requirements be adopted for 
metallic brake tubing and pipe as specified in SAE J1149 June 1991 
Metallic Air Brake System Tubing and Pipe. It disagreed with NHTSA's 
NPRM statement that such materials were no longer widely used in air 
brake systems. However, as NHTSA noted in the NPRM (68 FR 26386), it 
did not propose to adopt SAE standards relating to copper tubing, 
galvanized steel pipe, or end fittings used with metallic tubing 
because even though these materials are occasionally used in chassis 
plumbing, they are not considered to be brake hoses. It would therefore 
not be appropriate to incorporate the substantial requirements of SAE 
J1149 into FMVSS No. 106. There were no other comments on this issue, 
and in this final rule, NHTSA is not including requirements for metal 
air brake tubing and pipe into FMVSS No. 106.

VI. Statutory Bases for the Final Rule

    We have issued this final rule pursuant to our statutory authority. 
Under 49 U.S.C. Chapter 301, Motor Vehicle Safety (49 U.S.C. 30101 et 
seq.), the Secretary of Transportation is responsible for prescribing 
motor vehicle safety standards that are practicable, meet the need for 
motor vehicle safety, and are stated in objective terms. 49 U.S.C. 
30111(a). When prescribing such standards, the Secretary must consider 
all relevant, available motor vehicle safety information. 49 U.S.C. 
30111(b). The Secretary must also consider whether a proposed standard 
is reasonable, practicable, and appropriate for the type of motor 
vehicle or motor vehicle equipment for which it is prescribed and the 
extent to which the standard will further the statutory purpose of 
reducing traffic accidents and deaths and injuries resulting from 
traffic accidents. Id. Responsibility for promulgation of Federal motor 
vehicle safety standards was subsequently delegated to NHTSA. 49 U.S.C. 
105 and 322; delegation of authority at 49 CFR 1.50.
    As a Federal agency, before promulgating changes to a Federal motor 
vehicle safety standard, NHTSA also has a statutory responsibility to 
follow the informal rulemaking procedures mandated in the 
Administrative Procedure Act at 5 U.S.C. 553. Among these requirements 
are Federal Register publication of a general notice of proposed 
rulemaking, and giving interested persons an opportunity to participate 
in the rulemaking through submission of written data, views or 
arguments. After consideration of the public comments, we must 
incorporate into the rules adopted, a concise general statement of the 
rule's basis and purpose.
    The agency has carefully considered these statutory requirements in 
promulgating this final rule to amend FMVSS No. 106. As previously 
discussed in detail, we have solicited public comment in an NPRM and 
have carefully considered the public comments before issuing this final 
rule. As a result, we believe that this final rule reflects 
consideration of all relevant available motor vehicle safety 
information. Consideration of all these statutory factors has resulted 
in the following decisions in this final rule.
    This rulemaking began with NHTSA's proposal to adopt certain 
requirements relating to brake hoses, brake hose tubing, and brake hose 
fittings that are presently administered by the Federal Motor Carrier 
Safety Administration (FMCSA) into FMVSS No. 106. Since FMCSA proposed 
to remove brake hose provisions from its regulations, NHTSA believed it 
would meet the need for safety to incorporate the FMCSA requirements 
into FMVSS No. 106. In this way, NHTSA could continue to ensure the 
safety of commercial motor vehicle braking systems. NHTSA responded to 
an industry petition to include the FMCSA provisions into the FMVSSs.
    In the NPRM, NHTSA also sought to update FMVSS No. 106, which has 
not been substantially updated in many years. Thus, in the NPRM, NHTSA 
compared SAE standards with FMVSS No. 106 provisions, and proposed to 
include the provisions that it believed were the more rigorous. When 
SAE standards are used, NHTSA proposed to use the most current SAE 
standards. NHTSA also believed that it would better meet the need for 
safety to require that all brake hoses, not only those to be used on 
commercial vehicles, meet the new, upgraded FMVSS No. 106 requirements.
    Using this reasoning, NHTSA proposed to amend FMVSS No. 106's 
performance requirements and test procedures relating to: (a) Hydraulic 
brake hose; (b) air brake hose; (c) vacuum brake hose; (d) plastic air 
brake tubing; and (e) plastic air brake tubing assemblies and end 
fittings.
    In response to the NPRM, NHTSA received public comments from 11 
organizations and companies. The public commenters generally supported 
NHTSA's proposal to amend FMVSS No. 106 to include the latest 
requirements in the SAE brake hose standards. For many of the test 
conditions, the commenters provided detailed information on test 
methods and procedures.
    We have thoroughly reviewed the public comments and amended the 
final rule to reflect the comments. In a few instances where we did not 
adopt a comment, we explain why we believed it would not meet the need 
for safety to adopt the comment. We believe that this final rule, which 
combines the most rigorous requirements of the latest SAE standards, 
and of FMVSS No. 106, meets the need for safety.

VII. Effective Date

    In the NPRM, the agency proposed an effective date of two years 
after publication of a final rule (68 FR 35354). NHTSA received one 
comment on the effective date issue. SGPPL stated that it believes that 
two years to meet with the published changes would be sufficient. 
Accordingly, as proposed in the NPRM, this final rule will take effect 
two years after publication in today's edition of the Federal Register. 
At each manufacturer's discretion, optional early compliance will be 
permitted 60 days from the date this final rule is published in the 
Federal Register.

VIII. Rulemaking Analyses and Notices

A. Executive Order 12866 and DOT Regulatory Policies and Procedures

    Executive Order 12866, ``Regulatory Planning and Review'' (58 FR 
51735, October 4, 1993), provides for making determinations whether a 
regulatory action is ``significant'' and therefore subject to Office of 
Management and

[[Page 76319]]

Budget (OMB) review and to the requirements of the Executive Order. The 
Order defines a ``significant regulatory action'' as one that is likely 
to result in a rule that may:
    (1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local, or Tribal governments or 
communities;
    (2) Create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlements, grants, 
user fees, or loan programs or the rights and obligations or recipients 
thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    This notice was not reviewed under Executive Order 12866. Further, 
this notice was determined not to be significant within the meaning of 
the DOT Regulatory Policies and Procedures.
    In this document, NHTSA incorporates performance requirements and 
test procedures that are currently contained and/or referenced in the 
Federal Motor Carrier Safety Regulations. Those performance 
requirements/test procedures are based on voluntary standards adopted 
by the Society of Automotive Engineers. Although NHTSA incorporates the 
most recent versions of these SAE requirements/procedures and to apply 
them to brake hoses, tubing, and fittings for all motor vehicles, not 
just commercial motor vehicles, the agency concludes that most, if not 
all, such hoses, tubing, and fittings are already designed to meet the 
SAE requirements/procedures. However, in the event that there are some 
brake hose products that would need to be modified to comply with the 
proposed regulations, the agency (1) estimates that it is a small 
proportion of brake hose products that would need modification, as most 
are believed to already comply; and (2) concludes that the 
manufacturers of the components used in producing such products are not 
small businesses.
    For air brake hoses, both rubber hose and plastic tubing products, 
and hydraulic and vacuum brake hoses installed on vehicles that are 
typically used as commercial motor vehicles such as medium duty trucks, 
the agency concludes that all of the brake hose products already comply 
with the proposed regulations. The largest effect of the proposed 
regulations would be on the light vehicle sector including passenger 
cars and light trucks, of which approximately 16 million vehicles are 
produced each year. As the typical light vehicle is equipped with three 
to four brake hoses, 48 to 64 million hydraulic brake hose assemblies 
as installed in new vehicles would be affected, as well as an unknown 
quantity of replacement brake hoses for light vehicles, but probably a 
few million. In addition, the agency estimates that approximately 15.5 
million vacuum brake hoses and/or assemblies are installed on these 
vehicles.
    Since large quantities of brake hose material are needed to 
manufacture these brake hoses, the agency believes that there are large 
manufacturers that produce both hydraulic and vacuum brake hoses in 
such large quantities. There are many small companies that use the 
brake hose material and end fitting components to produce brake hose 
assemblies, but NHTSA does not anticipate that they would be affected 
by the proposed changes because they simply assemble already-compliant 
components supplied by the large manufacturers.
    The agency does not have data on the number of hydraulic and vacuum 
brake hose assemblies that must be modified to meet the final rule. 
Based on an informal survey of available hydraulic and vacuum brake 
hose assemblies, the agency estimates that perhaps as many as 20 
percent may need to be modified in some manner to comply with the final 
rule. Likewise, the agency does not know the cost to modify the 
manufacturing processes of the brake hose materials to comply with the 
final rule, but can assume that it would be for improved additives to 
elastomeric compounds or improved synthetic fibers used as reinforcing 
materials. Again, the agency does not have any data on the cost of 
manufacturing such materials, but estimates that the modification of 
such manufacturing processes would add not more than ten cents to the 
cost of each brake hose assembly.
    The highest-cost estimate of the final rule is based on production 
of 64 million new and replacement hydraulic brake hose assemblies, plus 
16 million new and replacement vacuum brake hoses/assemblies, for a 
total of 80 million total affected brake hoses. If 20 percent of these 
need to be modified to meet the final rule, at a cost of ten cents per 
hose, the total cost would be $1.6M.
    In response to the NPRM, a brake hose manufacturer commented on the 
cost of purchasing new test equipment for the ultraviolet resistance 
test for plastic air brake tubing. NHTSA believes that if it is 
necessary to purchase new test equipment (which NHTSA questions), the 
cost of such equipment may be on the order of $5,000 to $10,000, a sum 
that would not have a significant effect on NHTSA's estimated cost of 
this rulemaking.
    Therefore, the agency estimates the cost of complying with the 
changes resulting from the final rule to amend FMVSS No. 106 to be 
between zero and $1.6 million. This potential additional cost would 
not, however, be expected to have any impact on small businesses, but 
only on large manufacturers of brake hose materials that are produced 
in large quantities. Accordingly, the agency does not believe that this 
final rule would have any significant economic effects.
    The DOT's regulatory policies and procedures require the 
preparation of a full regulatory evaluation, unless the agency finds 
that the impacts of a rulemaking are so minimal as not to warrant the 
preparation of a full regulatory evaluation. Since anecdotal evidence 
suggests that most, if not all, of these hose, tubing, and fittings are 
already compliant with the minimum performance requirements that the 
agency is applying in this final rule, the agency believes that the 
impacts of this rulemaking would be minimal. Thus, it has not prepared 
a full regulatory evaluation.

B. Regulatory Flexibility Act

    Pursuant to the Regulatory Flexibility Act (5 U.S.C. 601 et seq., 
as amended by the Small Business Regulatory Enforcement Fairness Act 
(SBREFA) of 1996), whenever an agency is required to publish a notice 
of rulemaking for any proposed or final rule, it must prepare and make 
available for public comment a regulatory flexibility analysis that 
describes the effect of the rule on small entities (i.e., small 
businesses, small organizations, and small governmental jurisdictions). 
The Small Business Administration's regulations at 13 CFR Part 121 
define a small business, in part, as a business entity ``which operates 
primarily within the United States.'' (13 CFR Sec.  121.105(a)). No 
regulatory flexibility analysis is required if the head of an agency 
certifies that the rule will not have a significant economic impact on 
a substantial number of small entities. The SBREFA amended the 
Regulatory Flexibility Act to require Federal agencies to provide a 
statement of the factual basis for certifying that a rule will not have 
a significant economic impact on a substantial number of small 
entities.

[[Page 76320]]

    NHTSA has considered the effects of this rulemaking action under 
the Regulatory Flexibility Act. As explained above, NHTSA is 
incorporating performance requirements and test procedures that are 
currently contained or referenced in the Federal Motor Carrier Safety 
Regulations. Those performance requirements/test procedures are based 
on voluntary standards adopted by the Society of Automotive Engineers. 
Although NHTSA incorporates the most recent versions of these SAE 
requirements/procedures and to apply them to brake hoses, tubing, and 
fittings for all motor vehicles, not just commercial motor vehicles, 
the agency believes that most, if not all, such hoses, tubing, and 
fittings are already designed to meet the most recent SAE requirements/
procedures.
    For the remaining hoses, tubing, and fittings, estimated at up to 
20 percent of all hydraulic and vacuum brake hoses manufactured each 
year, the agency estimates the cost of complying with these 
requirements to be $1.6 million. Considering that the total number of 
hydraulic brake hose assemblies and vacuum brake hose/assemblies that 
would be subject to the requirements in this final rule is estimated to 
be approximately 80 million units annually, the agency estimates that 
the total annual effect of this final rule would be between zero and 
$1.6 million. Accordingly, I hereby certify that this final rule will 
not have a significant economic impact on a substantial number of small 
entities.

C. National Environmental Policy Act

    NHTSA has analyzed this rulemaking action for the purposes of the 
National Environmental Policy Act. The agency has determined that 
implementation of this action would not have any significant impact on 
the quality of the human environment.

D. Executive Order 13132 (Federalism)

    Executive Order 13132 requires NHTSA to develop an accountable 
process to ensure ``meaningful and timely input by State and local 
officials in the development of regulatory policies that have 
federalism implications.'' The Executive Order defines ``policies that 
have federalism implications'' to include regulations that have 
``substantial direct effects on the States, on the relationship between 
the national government and the States, or on the distribution of power 
and responsibilities among the various levels of government.'' Under 
Executive Order 13132, NHTSA may not issue a regulation with Federalism 
implications, that imposes substantial direct compliance costs, and 
that is not required by statute, unless the Federal government provides 
the funds necessary to pay the direct compliance costs incurred by 
State and local governments, the agency consults with State and local 
governments, or the agency consults with State and local officials 
early in the process of developing the proposed regulation. NHTSA also 
may not issue a regulation with Federalism implications and that 
preempts State law unless the agency consults with State and local 
officials early in the process of developing the proposed regulation.
    NHTSA has analyzed this rulemaking action in accordance with the 
principles and criteria set forth in Executive Order 13132. The agency 
has determined that this final rule will not have sufficient federalism 
implications to warrant consultation with State and local officials or 
the preparation of a federalism summary impact statement. The final 
rule will not have any substantial effects on the States, or on the 
current Federal-State relationship, or on the current distribution of 
power and responsibilities among the various local officials.

E. Civil Justice Reform

    This final rule will not have any retroactive effect. Under 49 
U.S.C. 30103, whenever a Federal motor vehicle safety standard is in 
effect, a State may not adopt or maintain a safety standard applicable 
to the same aspect of performance which is not identical to the Federal 
standard, except to the extent that the state requirement imposes a 
higher level of performance and applies only to vehicles procured for 
the State's use. 49 U.S.C. 30161 sets forth a procedure for judicial 
review of final rules establishing, amending, or revoking Federal motor 
vehicle safety standards. That section does not require submission of a 
petition for reconsideration or other administrative proceedings before 
parties may file suit in court.

F. Paperwork Reduction Act

    Under the Paperwork Reduction Act of 1995, a person is not required 
to respond to a collection of information by a Federal agency unless 
the collection displays a valid Office of Management and Budget (OMB) 
control number. This final rule includes no new ``collections of 
information'' as that term is defined by the OMB in 5 CFR Part 1320.

G. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272) 
directs NHTSA to use voluntary consensus standards in its regulatory 
activities unless doing so would be inconsistent with applicable law or 
otherwise impractical. Voluntary consensus standards are technical 
standards (e.g., materials specifications, test methods, sampling 
procedures, and business practices) that are developed or adopted by 
voluntary consensus standards bodies, such as the Society of Automotive 
Engineers (SAE). The NTTAA directs the agency to provide Congress, 
through the OMB, explanations when we decide not to use available and 
applicable voluntary consensus standards.
    The changes that NHTSA makes in this final rule are, for the most 
part, based on voluntary consensus standards adopted by the Society of 
Automotive Engineers. Accordingly, this final rule is in compliance 
with Section 12(d) of NTTAA.

H. Unfunded Mandates Reform Act

    Section 202 of the Unfunded Mandates Reform Act of 1995 (UMRA) 
requires Federal agencies to prepare a written assessment of the costs, 
benefits, and other effects of proposed or final rules that include a 
Federal mandate likely to result in the expenditure by State, local or 
tribal governments, in the aggregate, or by the private sector, of more 
than $100 million in any one year (adjusted for inflation with base 
year of 1995). Before promulgating a rule for which a written statement 
is needed, section 205 of the UMRA generally requires NHTSA to identify 
and consider a reasonable number of regulatory alternatives and adopt 
the least costly, most cost-effective, or least burdensome alternative 
that achieves the objectives of the rule. The provisions of section 205 
do not apply when they are inconsistent with applicable law. Moreover, 
section 205 allows NHTSA to adopt an alternative other than the least 
costly, most cost-effective or least burdensome alternative if the 
agency publishes with the final rule an explanation why that 
alternative was not adopted.
    This final rule would not result in the expenditure by State, 
local, or tribal governments, in the aggregate, or by the private 
sector of more than $100 million annually. The cost of complying with 
the requirements in this final rule is estimated to be between zero and 
$1.6M

[[Page 76321]]

annually. Accordingly, the agency has not prepared an Unfunded Mandates 
assessment.

I. Plain Language

    Executive Order 12866 requires each agency to write all rules in 
plain language. Application of the principles of plain language 
includes consideration of the following questions:

--Have we organized the material to suit the public's needs?
--Are the requirements in the rule clearly stated?
--Does the rule contain technical language or jargon that is not clear?
--Would a different format (grouping and order of sections, use of 
headings, paragraphing) make the rule easier to understand?
--Would more (but shorter) sections be better?
--Could we improve clarity by adding tables, lists, or diagrams?
--What else could we do to make this rulemaking easier to understand?

    If you have any responses to these questions, please include them 
in your comments to the agency.

J. Regulation Identifier Number (RIN)

    The Department of Transportation assigns a regulation identifier 
number (RIN) to each regulatory action listed in the Unified Agenda of 
Federal Regulations. The Regulatory Information Service Center 
publishes the Unified Agenda in April and October of each year. You may 
use the RIN contained in the heading at the beginning of this document 
to find this action in the Unified Agenda.

List of Subjects in 49 CFR Part 571

    Imports, Incorporation by Reference, Motor vehicle safety, Motor 
vehicles, Rubber and rubber products, and Tires.

0
In consideration of the foregoing, NHTSA amends 49 CFR part 571 as 
follows:

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

0
1. The authority for part 571 continues to read as follows:

    Authority: 49 U.S.C. 322, 30111, 30115, 30166, and 30177; 
delegation of authority at 49 CFR 1.50.

0
2. Section 571.106 is amended by:
0
a. Adding in S4 the definition of ``Preformed'' in the appropriate 
alphabetical order;
0
b. Revising the first sentence of paragraph (b) of S5.2.2;
0
c. Revising the first sentence of paragraph (b) of S5.2.4;
0
d. Revising S5.3 through S5.3.2;
0
e. Revising Table I;
0
f. Revising S5.3.4;
0
g. Revising S5.3.6;
0
h. Revising S5.3.8 and S5.3.9;
0
i. Revising S5.3.11;
0
j. Adding S5.3.12 and S5.3.13;
0
k. Revising paragraph (b) of S6.1.3;
0
l. Revising paragraph (c) of S6.2;
0
m. Revising S6.4;
0
n. Revising S6.4.2;
0
o. Revising S6.5;
0
p. Removing S6.5.1 and S6.5.2;
0
q. Revising paragraphs (a) and (b) of S6.6.1;
0
r. Revising paragraph (b) of S6.8.2;
0
s. Revising S6.9;
0
t. Revising paragraphs (a) and (b) in S6.9.1;
0
u. Removing S6.9.1(c) through (f);
0
v. Adding Figure 3 following S6.9.1(b);
0
w. Revising S6.9.2;
0
x. Removing S6.9.3;
0
y. Adding S6.10 through S6.12;
0
z. Adding Figure 4 following S6.12.2;
0
aa. Revising S7.1;
0
bb. Revising the first sentence in paragraph (b), and paragraphs (d), 
and (e) of S7.2.1;
0
cc. Revising Table III;
0
dd. Revising the first sentence in paragraph (b) and paragraph (d) of 
S7.2.2;
0
ee. Revising S7.3, S7.3.1, S7.3.2, and S7.3.3;
0
ff. Revising Table IV;
0
gg. Revising S7.3.5 through S7.3.11;
0
hh. Revising paragraphs (a) and (b) of S8.1;
0
ii. Revising paragraphs (a) and (c) in S8.2;
0
jj. Adding paragraph (d) in S8.2;
0
kk. Revising paragraph (b) in S8.3.2;
0
ll. Revising S8.4;
0
mm. Revising the heading of S8.6;
0
nn. Revising S8.7;
0
oo. Adding S8.7.1 and S8.7.2;
0
pp. Adding Figure 5 and the table accompanying Figure 5, following 
S8.7.1;
0
qq. Revising S8.8;
0
rr. Revising in S8.9 the introductory sentence and paragraph (a);
0
ss. Adding S8.13 and S8.14;
0
tt. Revising S9.2 and S9.2.1 through S9.2.3;
0
uu. Revising S9.2.7 through S9.2.10;
0
vv. Removing S9.2.11;
0
ww. Revising S10.1 and S10.2;
0
xx. Revising paragraph (a) of S10.6;
0
yy. Redesignating Figure 3 as Figure 6, following S10.6;
0
zz. Revising S10.7;
0
aaa. Removing and reserving S10.8;
0
bbb. Revising paragraph (b) in S10.9.2;
0
ccc. Redesignating Figure 4 as Figure 7, following S10.9.2(b);
0
ddd. Revising S10.10;
0
eee. Revising S11 and S11.1;
0
fff. Adding Table VII, following S11.1;
0
ggg. Revising S11.2;
0
hhh. Adding S11.2.1 through S11.2.3.1;
0
iii. Revising S11.3;
0
jjj. Adding S11.3.1 through S11.3.5;
0
kkk. Adding Table VIII, following S11.3.5;
0
lll. Adding S11.3.6 through S11.3.24;
0
mmm. Adding S12;
0
nnn. Adding S12.1 through S12.7;
0
ooo. Adding Figure 8, and the table accompanying Figure 8, following 
S12.7;
0
ppp. Adding S12.8 through S12.25;
0
qqq. Adding S13; and
0
rrr. Adding S13.1 through S13.3.
    The additions and revisions read as follows:


Sec.  571.106  Standard No. 106; Brake hoses.

* * * * *
    S4. Definitions.
* * * * *
    Preformed means a brake hose that is manufactured with permanent 
bends and is shaped to fit a specific vehicle without further bending.
* * * * *
    S5. Requirements--Hydraulic brake hose, brake hose assemblies, and 
brake hose end fittings.
* * * * *
    S5.2.2 * * *
* * * * *
    (b) A designation that identifies the manufacturer of the hose, 
which shall be filed in writing with: Office of Vehicle Safety 
Compliance, Equipment Division NVS-222, National Highway Traffic Safety 
Administration, 400 Seventh St. SW., Washington, DC 20590.* * *
* * * * *
    S5.2.4 * * *
* * * * *
    (b) A designation that identifies the manufacturer of the hose 
assembly, which shall be filed in writing with: Office of Vehicle 
Safety Compliance, Equipment Division NVS-222, National Highway Traffic 
Safety Administration, 400 Seventh St. SW., Washington, DC 20590. * * *
* * * * *
    S5.3 Test requirements. A hydraulic brake hose assembly or 
appropriate part thereof shall be capable of meeting any of the 
requirements set forth under this heading, when tested under the 
conditions of S13 and the applicable procedures of S6. However, a 
particular hose assembly or appropriate part thereof need not meet 
further requirements after having been subjected to and having met the 
constriction requirement (S5.3.1) and any one of the requirements 
specified in S5.3.2 through S5.3.13.

[[Page 76322]]

    S5.3.1 Constriction. Except for that part of an end fitting which 
does not contain hose, every inside diameter of any section of a 
hydraulic brake hose assembly shall be not less than 64 percent of the 
nominal inside diameter of the brake hose (S6.12).
    S5.3.2 Expansion and burst strength. The maximum expansion of a 
hydraulic brake hose assembly at 1,000 psi, 1,500 psi and 2,900 psi 
shall not exceed the values specified in Table I (S6.1), except that a 
brake hose larger than \3/16\ inch or 5 mm is not subject to the 2,900 
psi expansion test requirements. The hydraulic brake hose assembly 
shall then withstand water pressure of 4,000 psi for 2 minutes without 
rupture, and then shall not rupture at less than 7,000 psi for a \1/8\ 
inch, 3 mm, or smaller diameter hose, or at less than 5,000 psi for a 
hose with a diameter larger than \1/8\ inch or 3 mm (S6.2).

                          Table I.--Maximum Expansion of Free Length Brake Hose, CC/FT
----------------------------------------------------------------------------------------------------------------
                                                                    Test pressure
                                   -----------------------------------------------------------------------------
                                            1,000 psi                 1,500 psi                 2,900 psi
   Hydraulic brake hose, inside    -----------------------------------------------------------------------------
             diameter                 Regular        Low        Regular        Low        Regular        Low
                                     expansion    expansion    expansion    expansion    expansion    expansion
                                        hose         hose         hose         hose         hose         hose
----------------------------------------------------------------------------------------------------------------
\1/8\ inch, or 3 mm, or less......         0.66         0.33         0.79         0.42         1.21         0.61
\3/16\ inch, or 4 to 5 mm.........         0.86         0.55         1.02         0.72         1.67         0.91
\1/4\ inch, or 6 mm, or more......         1.04         0.82         1.30         1.17            *           *
----------------------------------------------------------------------------------------------------------------
*Not applicable.

* * * * *
    S5.3.4 Tensile strength. A hydraulic brake hose assembly shall 
withstand a pull of 325 pounds without separation of the hose from its 
end fittings during a slow pull test, and shall withstand a pull of 370 
pounds without separation of the hose from its end fittings during a 
fast pull test (S6.4).
* * * * *
    S5.3.6 Water absorption and tensile strength. A hydraulic brake 
hose assembly, after immersion in water for 70 hours (S6.5), shall 
withstand a pull of 325 pounds without separation of the hose from its 
end fittings during a slow pull test, and shall withstand a pull of 370 
pounds without separation of the hose from its end fittings during a 
fast pull test (S6.4).
* * * * *
    S5.3.8 Low-temperature resistance. A hydraulic brake hose 
conditioned at a temperature between minus 49 degrees Fahrenheit (minus 
45 degrees Celsius) and minus 54 degrees Fahrenheit (minus 48 degrees 
Celsius) for 70 hours shall not show cracks visible without 
magnification when bent around a cylinder as specified in S6.6 (S6.6).
    S5.3.9 Brake fluid compatibility, constriction, and burst strength. 
Except for brake hose assemblies designed for use with mineral or 
petroleum-based brake fluids, a hydraulic brake hose assembly shall 
meet the constriction requirement of S5.3.1 after having been subjected 
to a temperature of 248 degrees Fahrenheit (120 degrees Celsius) for 70 
hours while filled with SAE RM-66-04 ``Compatibility Fluid,'' as 
described in Appendix B of SAE Standard J1703, revised JAN 1995, 
``Motor Vehicle Brake Fluid.'' This incorporation by reference was 
approved by the Director of the Federal Register in accordance with 5 
U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from the 
Society of Automotive Engineers, Inc., 400 Commonwealth Drive, 
Warrendale, PA 15096-0001. Copies may be inspected at the National 
Highway Traffic Safety Administration, Technical Information Services, 
400 Seventh Street, SW., Plaza Level, Room 403, Washington, DC 20590, 
or at the National Archives and Records Administration (NARA). For 
information on the availability of this material at NARA, call 202-741-
6030, or go to: http://www.archives.gov/federal_register/code_of_federal regulations/ibr--locations.html. It shall then withstand water 
pressure of 4,000 psi for 2 minutes and thereafter shall not rupture at 
less than 5,000 psi (S6.2 except all sizes of hose are tested at 5,000 
psi).
* * * * *
    S5.3.11 Dynamic ozone test. A hydraulic brake hose shall not show 
cracks visible without magnification after having been subjected to a 
48-hour dynamic ozone test (S6.9).
    S5.3.12 High temperature impulse test. A brake hose assembly tested 
under the conditions in S6.10:
    (a) Shall withstand pressure cycling for 150 cycles, at 295 degrees 
Fahrenheit (146 degrees Celsius) without leakage;
    (b) Shall not rupture during a 2-minute, 4,000 psi pressure hold 
test, and;
    (c) Shall not burst at a pressure less than 5,000 psi.
    S5.3.13 End fitting corrosion resistance. After 24 hours of 
exposure to salt spray, a hydraulic brake hose end fitting shall show 
no base metal corrosion on the end fitting surface except where 
crimping or the application of labeling information has caused 
displacement of the protective coating (S6.11).
    S6. Test procedures--Hydraulic brake hose, brake hose assemblies, 
and brake hose end fittings.
* * * * *
    S6.1.3 Calculation of expansion at 1,000 psi, 1,500 psi and 2,900 
psi.
* * * * *
    (b) Close the valve to the burette, apply pressure at the rate of 
1,500 psi per minute, and seal 1,000 psi in the hose (1,500 in second 
series, and 2,900 psi in third series).
* * * * *
    S6.2 Burst strength test.
* * * * *
    (c) After 2 minutes at 4,000 psi, increase the pressure at the rate 
of 15,000 psi per minute until the pressure exceeds 5,000 psi for a 
brake hose larger than \1/8\ inch or 3 mm diameter, or until the 
pressure exceeds 7,000 psi for a brake hose of \1/8\ inch, 3 mm, or 
smaller diameter.
* * * * *
    S6.4 Tensile strength test. Utilize a tension testing machine 
conforming to the requirements of American Society for Testing and 
Materials (ASTM) E4-03, ``Standard Practices for Force Verification of 
Testing Machines,'' and provided with a recording device to measure the 
force applied. This incorporation by reference was approved by the 
Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 
1 CFR Part 51. Copies may be obtained from the American Society for 
Testing and Materials (ASTM) International, 100 Barr Harbor Drive,

[[Page 76323]]

P.O. Box C700, West Conshohocken, PA 19428-2959. Copies may be 
inspected at the National Highway Traffic Safety Administration, 
Technical Information Services, 400 Seventh St., S.W., Plaza Level, 
Room 403, Washington, D.C. 20590, or at the National Archives and 
Records Administration (NARA). For information on the availability of 
this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal regulations/ibr--
locations.html.
* * * * *
    S6.4.2 Operation. (a) Conduct the slow pull test by applying 
tension at a rate of 1 inch per minute travel of the moving head until 
separation occurs.
    (b) Conduct the fast pull test by applying tension at a rate of 2 
inches per minute travel of the moving head until separation occurs.
* * * * *
    S6.5 Water absorption sequence tests. (a) Prepare three brake hose 
assemblies and measure the free length of the hose assemblies.
    (b) Immerse the brake hose assemblies in distilled water at 185 
degrees Fahrenheit (85 degrees Celsius) for 70 hours. Remove the brake 
hose assemblies from the water and condition in air at room temperature 
for 30 minutes.
    (c) Conduct the tests in S6.2, S6.3, and S6.4, using a different 
hose for each sequence.
    S6.6 Low temperature resistance test.
    S6.6.1 Preparation. (a) Remove hose armor, if any, and condition 
the hose in a straight position in air at a temperature between minus 
49 degrees Fahrenheit and minus 54 degrees Fahrenheit (minus 45 degrees 
Celsius and minus 48 degrees Celsius) for 70 hours.
    (b) Condition a cylinder in air at a temperature between minus 49 
degrees Fahrenheit and minus 54 degrees Fahrenheit (minus 45 degrees 
Celsius and minus 48 degrees Celsius) for 70 hours, using a cylinder of 
2\1/2\ inches in diameter for tests of hose less than \1/8\ inch or 
3mm, 3 inches in diameter for tests of \1/8\ inch or 3 mm hose, 3\1/2\ 
inches in diameter for tests of \3/16\ to \1/4\ inch hose or 4 mm to 6 
mm hose, and 4 inches in diameter for tests of hose greater than \1/4\ 
inch or 6 mm in diameter.
* * * * *
    S6.8.2 Exposure to ozone.
* * * * *
    (b) Immediately thereafter, condition the hose on the cylinder for 
70 hours in an exposure chamber having an ambient air temperature of 
104 degrees Fahrenheit (40 degrees Celsius) during the test and 
containing air mixed with ozone in the proportion of 100 parts of ozone 
per 100 million parts of air by volume.
* * * * *
    S6.9 Dynamic ozone test.
    S6.9.1 Apparatus. Utilize a test apparatus shown in Figure 3 which 
is constructed so that:
    (a) It has a fixed pin with a vertical orientation over which one 
end of the brake hose is installed.
    (b) It has a movable pin that is oriented 30 degrees from vertical, 
with the top of the movable pin angled towards the fixed pin. The 
moveable pin maintains its orientation to the fixed pin throughout its 
travel in the horizontal plane. The other end of the brake hose is 
installed on the movable pin.
BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TR20DE04.004


[[Page 76324]]


    S6.9.2 Preparation. (a) Precondition the hose assembly by laying it 
on a flat surface in an unstressed condition, at room temperature, for 
24 hours.
    (b) Cut the brake hose assembly to a length of 8.6 inches (218 mm), 
such that no end fittings remain on the cut hose.
    (c) Mount the brake hose onto the test fixture by fully inserting 
the fixture pins into each end of the hose. Secure the hose to the 
fixture pins using a band clamp at each end of the hose.
    (d) Place the test fixture into an ozone chamber
    (e) Stabilize the atmosphere in the ozone chamber so that the 
ambient temperature is 104 [deg]F (40 degrees Celsius) and the air 
mixture contains air mixed with ozone in the proportion of 100 parts of 
ozone per 100 million parts of air by volume. This atmosphere is to 
remain stable throughout the remainder of the test.
    (f) Begin cycling the movable pin at a rate of 0.3 Hz. Continue the 
cycling for 48 hours.
    (g) At the completion of 48 hours of cycling, remove the test 
fixture from the ozone chamber. Without removing the hose from the test 
fixture, visually examine the hose for cracks without magnification, 
ignoring areas immediately adjacent to or within the area covered by 
the band clamps. Examine the hose with the movable pin at any point 
along its travel.
    S6.10 High temperature impulse test.
    S6.10.1 Apparatus. (a) A pressure cycling machine to which one end 
of the brake hose assembly can be attached, with the entire hose 
assembly installed vertically inside of a circulating air oven. The 
machine shall be capable of increasing the pressure in the hose from 
zero psi to 1600 psi, and decreasing the pressure in the hose from 1600 
psi to zero psi, within 2 seconds.
    (b) A circulating air oven that can reach a temperature of 295 
degrees Fahrenheit (146 degrees Celsius) within 30 minutes, and that 
can maintain a constant 295 degrees F (146 degrees Celsius) thereafter, 
with the brake hose assembly inside of the oven and attached to the 
pressure cycling machine.
    (c) A burst test apparatus to conduct testing specified in S6.2
    S6.10.2 Preparation. (a) Connect one end of the hose assembly to 
the pressure cycling machine and plug the other end of the hose. Fill 
the pressure cycling machine and hose assembly with SAE RM-66-04 
``Compatibility Fluid,'' as described in Appendix B of SAE Standard 
J1703, revised JAN 1995 ``Motor Vehicle Brake Fluid,'' and bleed all 
gases from the system.
    (b) Place the brake hose assembly inside of the circulating air 
oven in a vertical position. Increase the oven temperature to 295 
degrees F (146 degrees Celsius) and maintain this temperature 
throughout the pressure cycling test.
    (c) During each pressure cycle, the pressure in the hose is 
increased from zero psi to 1600 psi and held constant for 1 minute, 
then the pressure is decreased from 1600 psi to zero psi and held 
constant for 1 minute. Perform 150 pressure cycles on the brake hose 
assembly.
    (d) Remove the brake hose assembly from the oven, disconnect it 
from the pressure cycling machine, and drain the fluid from the hose. 
Cool the brake hose assembly at room temperature for 45 minutes.
    (e) Wipe the brake hose using acetone to remove residual 
Compatibility Fluid. Conduct the burst strength test in S6.2, except 
all sizes of hose are tested at 5,000 psi.
    S6.11 End fitting corrosion test. Utilize the apparatus described 
in ASTM B117-03, ``Standard Practice for Operating Salt Spray (Fog) 
Apparatus''. This incorporation by reference was approved by the 
Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 
1 CFR Part 51. Copies may be obtained from the American Society for 
Testing and Materials (ASTM) International, 100 Barr Harbor Drive, P.O. 
Box C700, West Conshohocken, PA 19428-2959. Copies may be inspected at 
the National Highway Traffic Safety Administration, Technical 
Information Services, 400 Seventh St., SW., Plaza Level, Room 403, 
Washington, DC 20590, or at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal regulations/ibr--
locations.html.
    S6.11.1 Construction. Construct the salt spray chamber so that:
    (a) The construction material does not affect the corrosiveness of 
the fog.
    (b) The hose assembly is supported or suspended 30 degrees from the 
vertical and parallel to the principal direction of the horizontal flow 
of fog through the chamber.
    (c) The hose assembly does not contact any metallic material or any 
material capable of acting as a wick
    (d) Condensation which falls from the assembly does not return to 
the solution reservoir for respraying.
    (e) Condensation from any source does not fall on the brake hose 
assemblies or the solution collectors.
    (f) Spray from the nozzles is not directed onto the hose assembly.
    S6.11.2 Preparation. (a) Plug each end of the hose assembly.
    (b) Mix a salt solution five parts by weight of sodium chloride to 
95 parts of distilled water, using sodium chloride substantially free 
of nickel and copper, and containing on a dry basis not more than 0.1 
percent of sodium iodide and not more than 0.3 percent total 
impurities. Ensure that the solution is free of suspended solids before 
the solution is atomized.
    (c) After atomization at 95 degrees Fahrenheit (35 degrees 
Celsius), ensure that the collected solution is in the PH range of 6.5 
to 7.2. Make the PH measurements at 77 degrees Fahrenheit (28 degrees 
Celsius).
    (d) Maintain a compressed air supply to the nozzle or nozzles free 
of oil and dirt and between 10 and 25 psi.
    S6.11.3 Operation. Subject the brake hose assembly to the salt 
spray continuously for 24 hours.
    (a) Regulate the mixture so that each collector will collect from 1 
to 2 milliliters of solution per hour for each 80 square centimeters of 
horizontal collecting area.
    (b) Maintain exposure zone temperature at 95 degrees Fahrenheit (35 
degrees Celsius).
    (c) Upon completion, remove the salt deposit from the surface of 
the hose by washing gently or dipping in clean running water not warmer 
than 100 degrees Fahrenheit (38 degrees Celsius) and then drying 
immediately.
    S6.12  Constriction test. Brake hose constriction test requirements 
shall be met using at least one of the methods specified in S6.12.1, 
S6.12.2, or S6.12.3.
    S6.12.1 Plug gauge. (a) Utilize a plug gauge as shown in Figure 4. 
Diameter ``A'' is equal to 64 percent of the nominal inside diameter of 
the hydraulic brake hose being tested.
    (b) Brake hose assemblies that are to be used for additional 
testing have constriction testing only at each end fitting. Other brake 
hose assemblies may be cut into 3-inch lengths to permit constriction 
testing of the entire assembly. Hose assemblies with end fittings that 
do not permit entry of the gauge (e.g., restrictive orifice or banjo 
fitting) are cut 3 inches from the point at which the hose terminates 
in the end fitting and then tested from the cut end.
    (c) Hold the brake hose in a straight position and vertical 
orientation.
    (d) Place the spherical end of the plug gauge just inside the hose 
or end fitting. If the spherical end will not enter the hose or end 
fitting using no more force than gravity acting on the plug gauge,

[[Page 76325]]

this constitutes failure of the constriction test.
    (e) Release the plug gauge. Within 3 seconds, the plug gauge shall 
fall under the force of gravity alone up to the handle of the gauge. If 
the plug gauge does not fully enter the hose up to the handle of the 
gauge within three seconds, this constitutes failure of the 
constriction test.
    S6.12.2 Extended plug gauge. (a) The test in 6.12.1 may be 
conducted with an extended plug gauge to enable testing of the entire 
brake hose from one end fitting, without cutting the brake hose. The 
extended plug gauge weight and spherical diameter specifications are as 
shown in Figure 4, but the handle portion of the gauge may be deleted 
and the gauge length may be greater than 3 inches.
    (b) The required performance of the extended plug gauge in 
S6.12.1(e) is that after the plug gauge is released, the extended plug 
gauge shall fall under the force of gravity alone at an average rate of 
1 inch per second until the spherical diameter of the extended gauge 
passes through all portions of the brake hose assembly containing hose. 
If the extended plug gauge does not pass through all portions of the 
brake hose assembly containing hose at an average rate of 1 inch per 
second, this constitutes failure of the constriction test.
BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TR20DE04.005

    S6.12.3 Drop ball test. (a) Utilize a rigid spherical ball with a 
diameter equal to 64 percent of the nominal inside diameter of the 
hydraulic brake hose being tested. The weight of the spherical ball 
shall not exceed 2 ounces (57 grams).
    (b) Hold the brake hose in a straight position and vertical 
orientation.
    (c) Hold the ball just above the end fitting.
    (d) Release the ball. The ball shall fall under the force of 
gravity alone completely through all portions of the brake hose 
assembly containing hose, at an average rate of 1 inch per second. 
Failure of the ball to pass completely through all portions of the 
brake hose assembly containing hose, at an average rate of 1 inch per 
second, constitutes failure of the constriction test.
* * * * *
    S7.1 Construction. Each air brake hose assembly shall be equipped 
with permanently attached brake hose end fittings or reusable brake 
hose end fittings. Each air brake hose constructed of synthetic or 
natural elastomeric rubber shall conform to the dimensional 
requirements specified in Table III, except for brake hose manufactured 
in metric sizes.
* * * * *
    S7.2.1 Hose. * * *
* * * * *
    (b) A designation that identifies the manufacturer of the hose, 
which shall be filed in writing with: Office of Vehicle Safety 
Compliance, Equipment Division NVS-222, National Highway Traffic Safety 
Administration, 400 Seventh St. SW., Washington, DC 20590.* * *
* * * * *
    (d) The nominal inside diameter of the hose expressed in inches or 
fractions of inches or in millimeters. The abbreviation ``mm'' shall 
follow hose sizes that are expressed in millimeters. (Examples: \3/8\, 
\1/2\ (\1/2\SP in the case of \1/2\ inch special air brake hose), 4mm, 
6mm.)
    (e) The type designation corresponding to the brake hose dimensions 
in Table III. Type A shall be labeled with the letter ``A'', Type AI 
shall be labeled with the letters ``AI'', and type AII shall be labeled 
with the letters ``AII''. Metric air brake hose shall be labeled with 
the letter ``A.''

[[Page 76326]]



   Table III.--Air Brake Hose Dimensions. Inside Diameter (ID) and Outside Diameter (OD) Dimensions in Inches
                                                  (Millimeters)
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
                                   TYPE A--HOSE SIZE--NOMINAL INSIDE DIAMETER
----------------------------------------------------------------------------------------------------------------
                                                   \1/4\     \5/16\        \3/        \7/      \1/2\      \5/8\
                                                                       8\\(1)\   16\\(1)\    SP\(1)\
-----------------------------------------------
Min...........................................     0.277      0.289      0.352      0.407      0.469      0.594
I.D...........................................     (5.8)      (7.3)      (8.9)     (10.3)     (11.9)     (15.1)
Max...........................................     0.273      0.335      0.398      0.469      0.531      0.656
I.D...........................................     (6.9)      (8.5)     (10.1)     (11.9)     (13.5)     (16.7)
Min...........................................     0.594      0.656      0.719      0.781      0.844      1.031
O.D...........................................    (15.1)     (16.7)     (18.3)     (19.8)     (21.4)     (26.2)
Max...........................................     0.656      0.719      0.781      0.843      0.906      1.094
O.D...........................................    (16.7)     (18.3)     (19.8)     (21.4)     (23.0)     (27.8)
-----------------------------------------------
                                TYPE AI\(2)\--HOSE SIZE--NOMINAL INSIDE DIAMETER
----------------------------------------------------------------------------------------------------------------
                                                  \3/16\      \1/4\     \5/16\    \13/32\      \1/2\      \5/8\
-----------------------------------------------
Min...........................................     0.188      0.250      0.312      0.406      0.500      0.625
I.D...........................................     (4.8)      (6.4)      (7.9)     (10.3)     (12.7)     (15.9)
Max...........................................     0.214      0.281      0.343      0.437      0.539      0.667
I.D...........................................     (5.4)      (7.1)      (8.7)     (11.1)     (13.7)     (16.9)
Min...........................................     0.472      0.535      0.598      0.714      0.808      0.933
O.D...........................................    (12.0)     (13.6)     (15.1)     (18.1)     (20.5)     (23.7)
Max...........................................     0.510      0.573      0.636      0.760      0.854      0.979
O.D...........................................    (13.0)     (14.6)     (16.2)     (19.3)     (21.7)     (24.9)
-----------------------------------------------
                                TYPE AII\(2)\--HOSE SIZE--NOMINAL INSIDE DIAMETER
----------------------------------------------------------------------------------------------------------------
                                                  \3/16\      \1/4\     \5/16\    \13/32\      \1/2\      \5/8\
-----------------------------------------------
Min...........................................     0.188      0.250      0.312      0.406      0.500      0.625
I.D...........................................     (4.8)      (6.4)      (7.9)     (10.3)     (12.7)     (15.9)
Max...........................................     0.214      0.281      0.343      0.437      0.539      0.667
I.D...........................................     (5.4)      (7.1)      (8.7)     (11.1)     (13.7)     (16.9)
Min...........................................     0.500      0.562      0.656      0.742      0.898      1.054
O.D...........................................    (12.7)     (14.3)     (16.7)     (18.8)     (22.8)     (26.8)
Max...........................................     0.539      0.602      0.695      0.789      0.945      1.101
O.D...........................................    (13.7)     (15.3)     (17.7)     (20.1)     (24.0)    (27.9)
----------------------------------------------------------------------------------------------------------------
Notes:
\(1)\ Type A, sizes \3/8\, \7/16\, and \1/2\ Special can be assembled with reusable end fittings. All sizes can
  be assembled using permanently-attached (crimped) end fittings.
\(2)\ Types AI and AII, all sizes, can be assembled with reusable or permanently-attached (crimped) end
  fittings.

    S7.2.2 End fittings. * * *
* * * * *
    (b) A designation that identifies the manufacturer of that 
component of the fitting, which shall be filed in writing with: Office 
of Vehicle Safety Compliance, Equipment Division NVS-222, National 
Highway Traffic Safety Administration, 400 Seventh St. S.W., 
Washington, DC 20590. * * *
* * * * *
    (d) The nominal inside diameter of the hose to which the fitting is 
properly attached expressed in inches or fractions of inches or in 
millimeters. (See examples in S7.2.1 (d).) The abbreviation ``mm'' 
shall follow hose sizes that are expressed in millimeters.
* * * * *
    S7.3 Test requirements. Each air brake hose assembly or appropriate 
part thereof shall be capable of meeting any of the requirements set 
forth under this heading, when tested under the conditions of S13 and 
the applicable procedures of S8. However, a particular hose assembly or 
appropriate part thereof need not meet further requirements after 
having met the constriction requirement (S7.3.1) and then having been 
subjected to any one of the requirements specified in S7.3.2 through 
S7.3.14.
    S7.3.1 Constriction. Every inside diameter of any section of an air 
brake hose assembly shall not be less than 66 percent of the nominal 
inside diameter of the brake hose. (S8.14)
    S7.3.2 High temperature resistance. An air brake hose shall not 
show external or internal cracks, charring, or disintegration visible 
without magnification when straightened after being bent for 70 hours 
at 212 degrees Fahrenheit (100 degrees Celsius) over a small test 
cylinder having the radius specified in Table IV for the size of hose 
tested. (S8.1)
    S7.3.3 Low temperature resistance. The inside and outside surfaces 
of an air brake hose shall not show cracks as a result of conditioning 
at minus 40 degrees Fahrenheit (minus 40 degrees Celsius) for 70 hours 
when bent around a large test cylinder having the radius specified in 
Table IV for the size of hose tested (S8.2).

                           Table IV.--Air Brake Hose Diameters and Test Cylinder Radii
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
Nominal hose inside diameter, inches\1\...    \3/16\     \1/4\    \5/16\     \3/8\   \13/32\   \7/16\,     \5/8\
                                                                                                 \1/2\
Nominal hose inside diameter,                   4, 5         6         8  ........        10        12        16
 millimeters\1\...........................
Small test cylinder, radius in inches         1 (25)    1\1/2\    1\3/4\    1\3/4\    1\7/8\    2 (51)    2\1/2\
 (millimeters)\2\.........................                (38)      (45)      (45)      (48)                (64)

[[Page 76327]]

 
Large test cylinder, radius in inches         2 (51)    2\1/2\    3 (76)    3\1/2\    3\1/2\   4 (102)    4\1/2\
 (millimeters)\3\.........................                (64)                (89)      (89)              (114)
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ These sizes are listed to provide test cylinder radii for brake hoses manufactured in these sizes. They do
  not represent conversions.
\2\ Small test cylinders are used for the high temperature resistance test.
\3\ Large test cylinders are used for the low temperature resistance, ozone resistance, and adhesion of wire-
  reinforced hose tests.

* * * * *
    S7.3.5 Ozone resistance. An air brake hose assembly shall not show 
cracks visible under 7-power magnification after exposure to ozone for 
70 hours at 104 degrees Fahrenheit (49 degrees Celsius) when bent 
around a test cylinder of the radius specified in Table IV for the size 
of hose tested (S8.4).
    S7.3.6 Length change. An air brake hose shall not contract in 
length more than 7 percent nor elongate more than 5 percent when 
subjected to air pressure of 200 psi (S8.5).
    S7.3.7 Adhesion. (a) Except for hose reinforced by wire, an air 
brake hose shall withstand a tensile force of 8 pounds per inch of 
length before separation of adjacent layers (S8.6).
    (b) An air brake hose reinforced by wire shall permit a steel ball 
to roll freely along the entire length of the inside of the hose when 
the hose is subjected to a vacuum of 25 inches of Hg and bent around a 
test cylinder (S8.13).
    S7.3.8 Flex strength and air pressure leakage. An air brake hose 
assembly of the length specified in the table accompanying Figure 5, 
when subjected to a flex test and internal pressure cycling, shall be 
capable of having its internal pressure increased from zero to 140 psi 
within 2 minutes with pressurized air supplied through an orifice 
(S8.7).
    S7.3.9 Corrosion resistance and burst strength. An air brake hose 
assembly exposed to salt spray shall not rupture when exposed to 
hydrostatic pressure of 900 psi (S8.8).
    S7.3.10 Tensile strength. An air brake hose assembly designed for 
use between a frame and axle or between a towed and towing vehicle 
shall withstand, without separation of the hose from its end fittings, 
a pull of 250 pounds if it is \1/4\ inch, 6 mm, or less in nominal 
inside diameter, or a pull of 325 pounds if it is larger than \1/4\ 
inch or 6 mm in nominal inside diameter. An air brake hose assembly 
designed for use in any other application shall withstand, without 
separation of the hose from its end fittings, a pull of 50 pounds if it 
is \1/4\ inch, 6 mm, or less in nominal inside diameter, 150 pounds if 
it is larger than \1/4\\ inch or 6 mm and equal to or smaller than \1/
2\ inch or 12 mm in nominal inside diameter, or 325 pounds if it is 
larger than \1/2\ inch or 12 mm in nominal inside diameter (S8.9).
    S7.3.11 Water absorption and tensile strength. After immersion in 
distilled water for 70 hours, an air brake hose assembly designed for 
use between a frame and axle or between a towed and a towing vehicle 
shall withstand, without separation of the hose from its end fittings, 
a pull of 250 pounds if it is \1/4\ inch or less or 6 mm or less in 
nominal inside diameter, or a pull of 325 pounds if it is larger than 
\1/4\ inch or 6 mm in nominal inside diameter. After immersion in 
distilled water for 70 hours, an air brake hose assembly designed for 
use in any other application shall withstand, without separation of the 
hose from its end fittings, a pull of 50 pounds if it is \1/4\ inch or 
6 mm or less in nominal inside diameter, 150 pounds if it is larger 
than \1/4\ inch or 6 mm and equal to or smaller than \1/2\ inch or 12 
mm in nominal inside diameter, or 325 pounds if it is larger than \1/2\ 
inch or 12 mm in nominal inside diameter. (S8.10)
* * * * *
    S8.1 High temperature resistance test.
    (a) Utilize a small test cylinder with a radius specified in Table 
IV for the size of hose tested.
    (b) Bind the hose around the cylinder and condition it in an air 
oven for 70 hours at 212 degrees Fahrenheit (100 degrees Celsius).
* * * * *
    S8.2 Low temperature resistance test. (a) Utilize a large test 
cylinder with a radius specified in Table IV for the size of hose 
tested.
* * * * *
    (c) With the hose and cylinder at minus 40 degrees Fahrenheit 
(minus 40 degrees Celsius), bend the hose 180 degrees around the 
cylinder at a steady rate in a period of 3 to 5 seconds. Remove the 
hose from the test cylinder and visibly examine the exterior of the 
hose for cracks without magnification.
    (d) Allow the hose to warm at room temperature for 2 hours. All 
reusable end fittings are removed from the hose. All permanently-
attached end fittings are cut away from the hose. Cut through one wall 
of the hose longitudinally along its entire length. Unfold the hose to 
permit examination of the interior surface. Visibly examine the 
interior of the hose for cracks without magnification.
* * * * *
    S8.3.2 Measurement.
* * * * *
    (b) Immerse each specimen in ASTM IRM 903 oil for 70 hours at 212 
degrees Fahrenheit (100 degrees Celsius) and then cool in ASTM IRM 903 
oil at room temperature for 30 to 60 minutes.
* * * * *
    S8.4 Ozone resistance test. Conduct the test specified in S6.8, 
using air brake hose, except use the large test cylinder specified in 
Table IV for the size of hose tested.
* * * * *
    S8.6 Adhesion test for air brake hose not reinforced by wire.
* * * * *
    S8.7 Flex strength and air pressure test.
    S8.7.1 Apparatus. A flex testing machine with a fixed hose assembly 
attachment point and a movable hose assembly attachment point, which 
meets the dimensional requirements of Figure 5 for the size of hose 
being tested. The attachment points connect to the end fittings on the 
hose assembly without leakage and, after the hose assembly has been 
installed for the flex test, are restrained from rotation. The movable 
end has a linear travel of 6 inches and a cycle rate of 100 cycles per 
minute. The machine is capable of increasing the air pressure in the 
hose assembly from zero to 150 psi within 2 seconds, and decreasing the 
air pressure in the hose assembly from 150 to zero psi within 2 
seconds.
BILLING CODE 4910-59-P

[[Page 76328]]

[GRAPHIC] [TIFF OMITTED] TR20DE04.006


                        Table Accompanying Figure 5.--Dimensions in Inches (Millimeters)
----------------------------------------------------------------------------------------------------------------
                                                                            Dimensions
                                                 ---------------------------------------------------------------
       Free hose length           Nominal hose            Position ``1''                  Position ``2''
                                 inside diameter ---------------------------------------------------------------
                                                     A       B       C     R (1)     A       B       C     R (1)
----------------------------------------------------------------------------------------------------------------
10.00 (254)...................  \3/16\, \1/4\...    3.00    2.75    3.75    1.40    3.00    2.75    3.75    1.20
                                                    (76)    (70)    (95)    (34)    (76)    (70)    (95)    (30)
11.00 (279)...................  \5/16\, \3/8\,      3.00    3.50    4.50    1.70    3.00    3.50    4.50    1.30
                                 \13/32\.           (76)    (89)   (114)    (43)    (76)    (89)   (114)    (33)
14.00 (355)...................  \7/16\, \1/2\,      3.00    4.00    5.00    2.20    3.00    4.00    5.00    1.80
                                 \5/8\.             (76)   (102)   (127)    (56)    (76)   (102)   (102)   (46)
----------------------------------------------------------------------------------------------------------------
Note (1) This is an approximate average radius.

    S8.7.2 Preparation. (a) Lay the hose material on a flat surface in 
an unstressed condition. Apply a permanent marking line along the 
centerline of the hose on the uppermost surface.
    (b) Prepare the hose assembly with a free length as shown in the 
table accompanying Figure 5. The end fittings shall be attached 
according to the end fitting manufacturer's instructions.
    (c) Plug the ends of the hose assembly and conduct the salt spray 
test in S6.11 using an air brake hose assembly. Remove the plugs from 
the end fittings.
    (d) Within 168 hours of completion of the salt spray test, expose 
the hose assembly to an air temperature of 212 degrees Fahrenheit (100 
degrees Celsius) for 70 hours, with the hose in a straight position. 
Remove the hose and cool it at room temperature for 2 hours. Within 166 
hours, subject the hose to the flexure test in S8.7.2(e).
    (e) Install the hose assembly on the flex testing machine as 
follows. With the movable hose attachment point at the mid point of its 
travel, attach one end of the hose to the movable attachment point with 
the marked line on the hose in the uppermost position. Attach the other 
end of the hose to the fixed attachment point allowing the hose to 
follow its natural curvature.
    (f) Cycle the air pressure in the hose by increasing the pressure 
in the hose from zero psi to 150 psi and holding constant for one 
minute, then decreasing the pressure from 150 psi to zero psi and 
holding constant for one minute. Continue the pressure cycling for the 
duration of the flex testing. Begin the flex testing by cycling the 
movable attachment point through 6 inches of travel at a rate of 100 
cycles per minute. Stop the flex testing and pressure cycling after one 
million flex cycles have been completed.
    (g) Install an orifice with a hole diameter of 0.0625 inches and a 
thickness of 0.032 inches in the air pressure supply line to the hose 
assembly. Provide a gauge or other means to measure air pressure in the 
hose assembly. Regulate the supply air pressure to the orifice to 150 
psi.
    (h) Apply 150 psi air pressure to the orifice. After 2 minutes have 
elapsed, measure the air pressure in the brake hose assembly, while 
pressurized air

[[Page 76329]]

continues to be supplied through the orifice.
    S8.8 Corrosion resistance and burst strength test. (a) Conduct the 
test specified in S6.11 using an air brake hose assembly. Remove the 
plugs from the ends of the hose assembly.
    (b) Fill the hose assembly with water, allowing all gases to 
escape. Apply water pressure at a uniform rate of increase of 
approximately 1,000 psi per minute until the hose ruptures.
    S8.9 Tensile strength test. Utilize a tension testing machine 
conforming to the requirements of American Society for Testing and 
Materials (ASTM) E4-03 ``Standard Practices for Force Verification of 
Testing Machines,'' and provided with a recording device to measure the 
force applied.
    (a) Attach an air brake hose assembly to the testing machine to 
permit straight, even, machine pull on the hose. Use adapters to mount 
hose assemblies equipped with angled end fittings so that the hose is 
in a straight position when installed on the machine.
* * * * *
    S8.13 Adhesion test for air brake hose reinforced by wire. (a) 
Place a steel ball with a diameter equal to 73 percent of the nominal 
inside diameter of the hose being tested inside of the hose. Plug one 
end of the hose. Attach the other end of the hose to a source of 
vacuum.
    (b) Subject the hose to a vacuum of 25 inches of Hg for five 
minutes. With the vacuum still applied to the hose, bend the hose 180 
degrees around a large test cylinder with a radius specified in Table 
IV for the size of hose tested. At the location of this bend, bend the 
hose 180 degrees around the test cylinder in the opposite direction.
    (c) With the vacuum still applied to the hose, return the hose to a 
straight position. Attempt to roll the ball inside the hose using 
gravity from one end of the hose to the other end.
    S8.14 Constriction test. Perform the constriction test in S6.12 
using an air brake hose, except that the spherical diameter ``A'' of 
the plug gauge in Figure 4, or the diameter of the rigid spherical ball 
in S6.12.3(a), shall be 66 percent of the nominal inside diameter of 
the air brake hose being tested.
* * * * *
    S9.2 Test requirements. Each vacuum brake hose assembly or 
appropriate part thereof shall be capable of meeting any of the 
requirements set forth under this heading, when tested under the 
conditions of S13 and the applicable procedures of S10. However, a 
particular hose assembly or appropriate part thereof need not meet 
further requirements after having met the constriction requirement 
(S9.2.1) and then having been subjected to any one of the requirements 
specified in S9.2.2 through S9.2.10.
    S9.2.1 Constriction. Except for that part of an end fitting which 
does not contain hose, every inside diameter of any section of a vacuum 
brake hose assembly shall be not less than 75 percent of the nominal 
inside diameter of the hose if for heavy duty, or 70 percent of the 
nominal inside diameter of hose if for light duty (S10.10).
    S9.2.2 High temperature resistance. A vacuum brake hose tested 
under the conditions specified in S10.1:
    (a) Shall not have collapse of the outside diameter exceeding 10 
percent of the initial outside diameter for a heavy-duty vacuum brake 
hose, or exceeding 15 percent of the initial outside diameter for a 
light-duty vacuum brake hose;
    (b) Shall not show external cracks, charring, or disintegration 
visible without magnification, and;
    (c) Shall not leak when subjected to a hydrostatic pressure test.
    S9.2.3 Low temperature resistance. A vacuum brake hose tested under 
the conditions specified in S10.2 shall:
    (a) Not show cracks visible without magnification after 
conditioning at minus 40 degrees Fahrenheit (minus 40 degrees Celsius) 
for 70 hours when bent around a cylinder having the radius specified in 
Table V for the size hose tested; and
    (b) Not leak when subjected to a hydrostatic pressure test (S10.6).
* * * * *
    S9.2.7 Bend. The collapse of the outside diameter of a vacuum brake 
hose, other than a preformed vacuum brake hose, at the middle point of 
the test length when bent until the ends touch shall not exceed the 
values given in Table V for the size of hose tested (S10.6).
    S9.2.8 Swell and adhesion. Following exposure to Reference Fuel B, 
every inside diameter of any section of a vacuum brake hose shall not 
be less than 75 percent of the nominal inside diameter of the hose if 
for heavy duty, or 70 percent of the nominal inside diameter of the 
hose if for light duty. The vacuum brake hose shall show no leakage in 
a vacuum test of 26 inches of Hg for 10 minutes. A vacuum hose that is 
constructed of two or more layers shall withstand a force of 6 pounds 
per inch of length before separation of adjacent layers. (S10.7).
    S9.2.9 Deformation. A vacuum brake hose shall return to 90 percent 
of its original outside diameter within 60 seconds after five 
applications of force as specified in S10.8, except that a wire-
reinforced hose need only return to 85 percent of its original outside 
diameter. In the case of a heavy duty hose, the first application of 
force shall not exceed a peak value of 70 pounds, and the fifth 
application of force shall reach a peak value of at least 40 pounds. In 
the case of light duty hose the first application of force shall not 
exceed a peak value of 50 pounds, and the fifth application of force 
shall reach a peak value of at least 20 pounds (S10.9).
    S9.2.10 End fitting corrosion resistance. After 24 hours of 
exposure to salt spray, vacuum brake hose end fittings shall show no 
base metal corrosion of the end fitting surface except where crimping 
or the application of labeling information has caused displacement of 
the protective coating. (S10.10).
* * * * *
    S10. Test procedures--Vacuum brake hose, brake hose assemblies, and 
brake hose end fittings.
    S10.1 High temperature resistance test. (a) Measure the initial 
outside diameter of the hose.
    (b) Subject the hose to an internal vacuum of 26 inches of Hg at an 
ambient temperature of 257 degrees Fahrenheit (125 degrees Celsius) for 
a period of 96 hours. Remove the hose to room temperature and 
atmospheric pressure.
    (c) Within 5 minutes of completion of the conditioning in S10.1(b), 
measure the outside diameter at the point of greatest collapse and 
calculate the percentage collapse based on the initial outside 
diameter.
    (d) Cool the hose at room temperature for 5 hours. Bend the hose 
around a mandrel with a diameter equal to five times the initial 
outside diameter of the hose. Examine the exterior of the hose for 
cracks, charring, or disintegration visible without magnification. 
Remove the hose from the mandrel.
    (e) Fill the hose assembly with water, allowing all gases to 
escape. Apply water pressure in the hose of 175 psi within 10 seconds. 
Maintain an internal hydrostatic pressure of 175 psi for one minute and 
examine the hose for visible leakage.
    S10.2 Low temperature resistance test. (a) Conduct the test 
specified in S8.2(a) through (c) using vacuum brake hose with the 
cylinder radius specified in Table V for the size of hose tested.
    (b) Remove the hose from the test cylinder, warm the hose at room 
temperature for 5 hours, and conduct the hydrostatic pressure test in 
S10.1(e).
* * * * *

[[Page 76330]]

    S10.6 Bend test. (a) Bend a vacuum brake hose, of the length 
prescribed in Table V, in the direction of its normal curvature until 
the ends just touch as shown in Figure 6.
* * * * *
    S10.7 Swell and adhesion test. (a) Fill a specimen of vacuum brake 
hose 12 inches long with ASTM Reference Fuel B as described in ASTM 
D471-98 [egr]\1\ Standard Test Method for Rubber Property--
Effect of Liquids. This incorporation by reference was approved by the 
Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 
1 CFR part 51. Copies may be obtained from the American Society for 
Testing and Materials (ASTM) International, 100 Barr Harbor Drive, P.O. 
Box C700, West Conshohocken, PA 19428-2959. Copies may be inspected at 
the National Highway Traffic Safety Administration, Technical 
Information Services, 400 Seventh St., SW., Plaza Level, Room 403, 
Washington, DC 20590, or at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federalregulations/ibr_locations.html.
    (b) Maintain reference fuel in the hose under atmospheric pressure 
at room temperature for 48 hours.
    (c) Remove fuel and conduct the constriction test in S10.10.
    (d) Attach the hose to a source of vacuum and subject it to a 
vacuum of 26 inches of Hg for 10 minutes. Remove the hose from the 
vacuum source.
    (e) For a vacuum brake hose constructed of two or more layers, 
conduct the test specified in S8.6 using the vacuum brake hose.
    S10.8 [Reserved]
* * * * *
    S10.9.2 Operation.
* * * * *
    (b) Apply gradually increasing force to the test specimen to 
compress its inside diameter to that specified in Table VI (dimension D 
of Figure 7) for the size of hose tested.
* * * * *
    S10.10 Constriction test. Perform the constriction test in S6.12 
using a vacuum brake hose, except that the spherical diameter ``A'' of 
the plug gauge in Figure 4, or the diameter of the rigid spherical ball 
in S6.12.3(a), shall be 75 percent of the nominal inside diameter of 
the vacuum brake hose if it is heavy duty, or 70 percent of the nominal 
inside diameter of the vacuum brake hose if it is light duty.
    S11. Requirements--Plastic air brake tubing, plastic air brake 
tubing assemblies, and plastic air brake tubing end fittings.
    11.1 Construction. Each plastic air brake tubing assembly shall be 
equipped with permanently attached end fittings or reusable end 
fittings. Plastic air brake tubing shall conform to the dimensional 
requirements specified in Table VII. (S12.1)

                                                     Table VII.--Plastic Air Brake Tubing Dimensions
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Maximum outside   Minimum outside   Nominal inside     Nominal wall     Wall thickness
                                                                    diameter          diameter          diameter          thickness         tolerance
                Nominal tubing outside diameter                -----------------------------------------------------------------------------------------
                                                                   mm     inches     mm     inches     mm     inches     mm     inches     mm     inches
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1/8\ inch....................................................     3.25    0.128     3.10    0.122     2.01    0.079     0.58    0.023     0.08    0.003
\5/32\ inch...................................................     4.04    0.159     3.89    0.153     2.34    0.092     0.81    0.032     0.08    0.003
\3/16\ inch...................................................     4.83    0.190     4.67    0.184     2.97    0.117     0.89    0.035     0.08    0.003
\1/4\ inch....................................................     6.43    0.253     6.27    0.247     4.32    0.170     1.02    0.040     0.08    0.003
\5/16\ inch...................................................     8.03    0.316     7.82    0.308     5.89    0.232     1.02    0.040     0.10    0.004
\3/8\ inch....................................................     9.63    0.379     9.42    0.371     6.38    0.251     1.57    0.062     0.10    0.004
\1/2\ inch....................................................    12.83    0.505    12.57    0.495     9.55    0.376     1.57    0.062     0.10    0.004
\5/8\ inch....................................................    16.00    0.630    15.75    0.620    11.20    0.441     2.34    0.092     0.13    0.005
\3/4\ inch....................................................    19.18    0.755    18.92    0.745    14.38    0.566     2.34    0.092     0.13    0.005
6 mm..........................................................     6.10    0.240     5.90    0.232     4.00    0.157     1.00    0.039     0.10    0.004
8 mm..........................................................     8.10    0.319     7.90    0.311     6.00    0.236     1.00    0.039     0.10    0.004
10 mm.........................................................    10.13    0.399     9.87    0.389     7.00    0.276     1.50    0.059     0.10    0.004
12 mm.........................................................    12.13    0.478    11.87    0.467     9.00    0.354     1.50    0.059     0.10    0.004
16 mm.........................................................    16.13    0.635    15.87    0.625    12.00    0.472     2.00    0.079     0.13    0.005
--------------------------------------------------------------------------------------------------------------------------------------------------------

    S11.2 Labeling.
    S11.2.1 Plastic air brake tubing. Plastic air brake tubing shall be 
labeled, or cut from bulk tubing that is labeled, at intervals of not 
more than 6 inches, measured from the end of one legend to the 
beginning of the next, in block capital letters and numerals at least 
one-eighth of an inch high, with the information listed in paragraphs 
(a) through (e) of this section. The information need not be present on 
tubing that is sold as part of a motor vehicle.
    (a) The symbol DOT, constituting a certification by the hose 
manufacturer that the hose conforms to all applicable motor vehicle 
safety standards.
    (b) A designation that identifies the manufacturer of the tubing, 
which shall be filed in writing with: Office of Vehicle Safety 
Compliance, Equipment Division NVS-222, National Highway Traffic Safety 
Administration, 400 Seventh St. SW., Washington, DC 20590. The 
designation may consist of block capital letters, numerals, or a 
symbol.
    (c) The month, day, and year, or the month and year, of 
manufacture, expressed in numerals. For example, 10/1/96 means October 
1, 1996.
    (d) The nominal outside diameter expressed in inches or fractions 
of inches or in millimeters followed by the letters OD. The 
abbreviation ``mm'' shall follow tubing sizes that are expressed in 
millimeters. (Examples: \3/8\ OD, 6 mm OD.)
    (e) The letter ``A'' shall indicate intended use in air brake 
systems.
    S11.2.2 End fittings. Except for an end fitting that is attached by 
deformation of the fitting about the tubing by crimping or swaging, at 
least one component of each plastic air brake tubing end fitting shall 
be etched, embossed, or stamped in block capital letters and numerals 
at least one-sixteenth of an inch high with the following information:
    (a) The symbol DOT, constituting a certification by the 
manufacturer that the end fitting conforms to all applicable motor 
vehicle safety standards.
    (b) A designation that identifies the manufacturer of the end 
fitting, which shall be filed in writing with: Office of

[[Page 76331]]

Vehicle Safety Compliance, Equipment Division NVS-222, National Highway 
Traffic Safety Administration, 400 Seventh St. SW., Washington, DC 
20590. The designation may consist of block capital letters, numerals, 
or a symbol.
    (c) The letter ``A'' shall indicate intended use in air brake 
systems.
    (d) The nominal outside diameter of the plastic tubing to which the 
fitting is properly attached expressed in inches or fractions of inches 
or in millimeters followed by the letters OD. The abbreviation ``mm'' 
shall follow tubing sizes that are expressed in millimeters. (Examples: 
\3/8\ OD, 6 mm OD)
    S11.2.3. Assemblies. Each plastic air brake tubing assembly made 
with end fittings that are attached by crimping or swaging, except 
those sold as part of a motor vehicle, shall be labeled by means of a 
band around the brake tubing assembly as specified in this paragraph 
or, at the option of the manufacturer, by means of labeling as 
specified in S11.2.3.1. The band may at the manufacturer's option be 
attached so as to move freely along the length of the assembly, as long 
as it is retained by the end fittings. The band shall be etched, 
embossed, or stamped in block capital letters, numerals or symbols at 
least one-eighth of an inch high, with the following information:
    (a) The symbol DOT, constituting certification by the tubing 
assembler that the tubing assembly conforms to all applicable motor 
vehicle safety standards.
    (b) A designation that identifies the manufacturer of the hose 
assembly, which shall be filed in writing with: Office of Vehicle 
Safety Compliance, Equipment Division NVS-222, National Highway Traffic 
Safety Administration, 400 Seventh St. SW., Washington, DC 20590. The 
designation may consist of block capital letters, numerals, or a 
symbol.
    S11.2.3.1 At least one end fitting of a plastic air brake tubing 
assembly made with end fittings that are attached by crimping or 
swaging shall be etched, stamped, or embossed with a designation at 
least one-sixteenth of an inch high that identifies the manufacturer of 
the tubing assembly and is filed in accordance with S11.2.3(b).
    S11.3 Test requirements. Each plastic air brake tubing assembly or 
appropriate part thereof shall be capable of meeting any of the 
requirements set forth under this heading, when tested under the 
conditions of S13 and the applicable procedures of S12. However, a 
particular tubing assembly or appropriate part thereof need not meet 
further requirements after having met the constriction requirement 
(S11.3.1) and then having been subjected to any one of the requirements 
specified in S11.3.2 through S11.3.22. Unless otherwise specified, 
testing is conducted on a sample of tubing 12 inches in length.
    S11.3.1 Constriction. Every inside diameter of any section of a 
plastic air brake tubing assembly shall not be less than 66 percent of 
the nominal inside diameter of the brake tubing. (S12.2)
    S11.3.2 High temperature conditioning and dimensional stability. 
Plastic air brake tubing shall conform to the dimensions in Table VII 
after conditioning in air at 230 degrees Fahrenheit (110 degrees 
Celsius) for four hours. (S12.3)
    S11.3.3 Boiling water conditioning and dimensional stability. 
Plastic air brake tubing shall conform to the dimensions in Table VII 
after conditioning in boiling water for two hours. (S12.4)
    S11.3.4 Burst Strength. Plastic air brake tubing shall not rupture 
when subjected to the burst strength pressure in Table VIII for the 
size of tubing being tested. (S12.5)
    S11.3.5 Moisture absorption and burst strength. Plastic air brake 
tubing shall not rupture when subjected to 80 percent of the burst 
strength pressure in Table VIII, after the tubing has been dried in an 
oven and then conditioned in a 100 percent relative humidity atmosphere 
at 75 degrees Fahrenheit (24 degrees Celsius) for 100 hours. (S12.6)

                           Table VIII.--Plastic Air Brake Tubing Mechanical Properties
----------------------------------------------------------------------------------------------------------------
                                           Burst strength    Supported bend   Unsupported bend     Conditioned
                                              pressure         radius \1\        radius \2\       tensile load
            Nominal tubing OD            -----------------------------------------------------------------------
                                            kPa      Psi       Mm     inches     mm     inches     N       lbf
----------------------------------------------------------------------------------------------------------------
\1/8\ inch..............................     6900     1000      9.4     0.37      9.4     0.37      156       35
\5/32\ inch.............................     8300     1200     12.7     0.50     12.7     0.50      178       40
\3/16\ inch.............................     8300     1200     19.1     0.75     19.1     0.75      222       50
\1/4\ inch..............................     8300     1200     25.4     1.00     25.4     1.00      222       50
\5/16\ inch.............................     6900     1000     31.8     1.25     38.1     1.50      334       75
\3/8\ inch..............................     9700     1400     38.1     1.50     38.1     1.50      667      150
\1/2\ inch..............................     6600      950     50.8     2.00     63.5     2.50      890      200
\5/8\ inch..............................     6200      900     63.5     2.50     76.2     3.00     1446      325
\3/4\ inch..............................     5500      800     76.2     3.00     88.9     3.50     1557      350
6 mm....................................     7600     1100     20.0     0.75     25.4     1.00      222       50
8 mm....................................     6200      900     31.8     1.25     38.1     1.50      334       75
10 mm...................................     8200     1200     38.1     1.50     38.1     1.50      667      150
12 mm...................................     6900     1000     44.5     1.75     63.5     2.50      890      200
16 mm...................................     6000      875     69.9     2.75     76.2     3.00     1446     325
----------------------------------------------------------------------------------------------------------------
Notes: (1) Supported bend radius for tests specifying cylinders around which the tubing is bent. (2) Unsupported
  bend radius for the collapse resistance test in which the tubing is not supported by a cylinder during
  bending.

    S11.3.6 Ultraviolet light resistance. Plastic air brake tubing 
shall not rupture when subjected to 80 percent of the burst strength 
pressure in Table VIII for the size of tubing being tested, after being 
exposed to ultraviolet light for 300 hours and then impacted with a one 
pound weight dropped from a height of 12 inches. (S12.7)
    S11.3.7 Low temperature flexibility. The outer surface of plastic 
air brake tubing shall not show cracks visible without magnification as 
a result of conditioning in air at 230 degrees Fahrenheit (110 degrees 
Celsius) for 24 hours, and then conditioning in air at minus 40 degrees 
Fahrenheit (minus 40 degrees Celsius) for four hours, and then bending 
the tubing 180 degrees around a test cylinder having a radius equal to 
six times the nominal outside diameter of the tubing. (S12.8)

[[Page 76332]]

    S11.3.8 High temperature flexibility. Plastic air brake tubing 
shall not rupture or burst when subjected to 80 percent of the burst 
strength pressure in Table VIII for the size of tubing being tested, 
after the tubing has been:
    (a) Conditioned in air at 230 degrees Fahrenheit (110 degrees 
Celsius) for 72 hours while bent 180 degrees around a cylinder having a 
radius equal to the supported bend radius in Table VIII for the size of 
tubing being tested; and
    (b) Cooled to room temperature while remaining on the cylinder, 
then straightened; and
    (c) Bent 180 degrees around the cylinder in the opposite direction 
of the first bending. (S12.9)
    S11.3.9 High temperature resistance. Plastic air brake tubing shall 
not rupture or burst when subjected to 80 percent of the burst strength 
pressure in Table VIII for the size of tubing being tested, after the 
tubing has been conditioned in air at 230 degrees Fahrenheit (110 
degrees Celsius) for 72 hours. (S12.10)
    S11.3.10 High temperature conditioning, low temperature impact 
resistance. Plastic air brake tubing shall not rupture or burst when 
subjected to 80 percent of the burst strength pressure in Table VIII 
for the size of tubing being tested, after the tubing has been 
conditioned in air at 230 degrees Fahrenheit (110 degrees Celsius) for 
24 hours, then conditioned in air at minus 40 degrees Fahrenheit (minus 
40 degrees Celsius) for 4 hours and impacted with a one pound weight 
dropped from a height of 12 inches. (S12.11)
    S11.3.11 Boiling water conditioning, low temperature impact 
resistance. Plastic air brake tubing shall not rupture when subjected 
to 80 percent of the burst strength pressure in Table VIII for the size 
of tubing being tested, after the tubing has been conditioned in 
boiling water for two hours, then conditioned in air at minus 40 
degrees Fahrenheit (minus 40 degrees Celsius) for 4 hours, and then 
impacted with a one pound weight dropped from a height of 12 inches. 
(S12.12)
    S11.3.12 Zinc chloride resistance. The outer surface of plastic air 
brake tubing shall not show cracks visible under 7-power magnification 
after immersion in a 50 percent zinc chloride aqueous solution for 200 
hours while bent around a cylinder having a radius equal to the 
supported bend radius in Table VIII for the size of tubing tested. 
(S12.13)
    S11.3.13 Methyl alcohol resistance. The outer surface of plastic 
air brake tubing shall not show cracks visible under 7-power 
magnification after immersion in a 95 percent methyl alcohol aqueous 
solution for 200 hours while bent around a cylinder having a radius 
equal to the supported bend radius in Table VIII for the size of tubing 
tested. (S12.14)
    S11.3.14 High temperature conditioning and collapse resistance. The 
collapse of the outside diameter of plastic air brake tubing shall not 
exceed twenty percent of the original outside diameter when bent 180 
degrees on a holding fixture to the unsupported bend radius specified 
in Table VIII and conditioned in air at 200 degrees Fahrenheit (93 
degrees Celsius) for 24 hours. (S12.15)
    S11.3.15 Ozone resistance. The outer surface of plastic air brake 
tubing shall not show cracks visible under 7-power magnification after 
exposure to ozone for 70 hours at 104 degrees Fahrenheit (40 degrees 
Celsius). (S12.16)
    S11.3.16 Oil resistance. Plastic air brake tubing shall not rupture 
when subjected to 80 percent of the burst strength pressure in Table 
VIII for the size of tubing being tested, after the tubing has been 
conditioned in ASTM IRM 903 oil at 212 degrees Fahrenheit (100 degrees 
Celsius) for 70 hours. (S12.17)
    S11.3.17 Tensile strength. A plastic air brake tubing assembly 
designed for use between frame and axle or between a towed and a towing 
vehicle shall withstand, without separation of the tubing from its end 
fittings, a pull of 250 pounds if it is \3/8\ inch, 10 mm, or less in 
nominal outside diameter, or a pull of 325 pounds if it is larger than 
\3/8\ inch or 10 mm in nominal outside diameter. A plastic air brake 
tubing assembly designed for use in any other application shall 
withstand, without separation of the hose from its end fittings, a pull 
of 35 pounds if it is \1/8\ inch, 3 mm, or less in nominal outside 
diameter, 40 pounds if it is \5/32\ inch or 4 mm in nominal outside 
diameter, 50 pounds if it is \3/16\ to \3/8\ inch or 5 mm to 10 mm in 
nominal outside diameter, 150 pounds if it is \1/2\ to \5/8\ inch or 11 
mm to 16 mm in nominal outside diameter, or 325 pounds if it is larger 
than \5/8\ inch or 16 mm in nominal outside diameter. (S12.18)
    S11.3.18 Boiling water conditioning and tensile strength. A plastic 
air brake tubing assembly when subjected to a tensile pull test shall 
either elongate 50 percent or withstand the conditioned tensile load in 
Table VIII without separation from its end fittings, with one end of 
the assembly conditioned in boiling water for 5 minutes. (S12.19)
    S11.3.19 Thermal conditioning and tensile strength. A plastic air 
brake tubing assembly when subjected to a tensile pull test shall 
either elongate 50 percent or withstand the conditioned tensile load in 
Table VIII without separation from its end fittings after the assembly 
has been subjected to four cycles of conditioning in air at minus 40 
degrees Fahrenheit (minus 40 degrees Celsius) for thirty minutes, 
normalizing at room temperature, conditioning in boiling water for 15 
minutes, and normalizing at room temperature. (S12.20)
    S11.3.20 Vibration resistance. A plastic air brake tubing assembly 
with an internal air pressure of 120 psig shall not rupture or leak 
more than 50 cm3 per minute at a temperature of minus 40 
degrees Fahrenheit (minus 40 degrees Celsius) and 25 cm3 per 
minute at a temperature of 75 degrees Fahrenheit (24 degrees Celsius), 
after the assembly has been subjected to 1,000,000 cycles of vibration 
testing with one end of the assembly fixed and the other end stroked 
\1/2\-inch at 600 cycles per minute. In addition, end fittings that use 
a threaded retention nut shall retain at least 20 percent of the 
original retention nut tightening torque upon completion of the 
vibration testing. The vibration test shall be conducted in an 
environmental chamber and the air temperature shall be cycled between 
minus 40 degrees Fahrenheit (minus 40 degrees Celsius) and 220 degrees 
Fahrenheit (104 degrees Celsius) during the test. (S12.21)
    S11.3.21 End fitting retention. The end fittings of a plastic air 
brake tubing assembly shall not rupture when the assembly is filled 
with water and pressurized to the burst strength pressure in Table 
VIII. (S12.22)
    S11.3.22 Thermal conditioning and end fitting retention. The end 
fittings of a plastic air brake tubing assembly shall not rupture when 
the tubing assembly is filled with ASTM IRM 903 oil and:
    (a) Conditioning in air at 200 degrees Fahrenheit (93 degrees 
Celsius) for 24 hours with atmospheric pressure inside the tubing 
assembly; and
    (b) Increasing the pressure inside the tubing assembly to 450 psi, 
and holding this pressure for five minutes while maintaining an air 
temperature of 200 degrees Fahrenheit (93 degrees Celsius); and
    (c) Reducing the pressure inside the tubing assembly to atmospheric 
and permitting the tubing assembly to cool at 75 degrees Fahrenheit (24 
degrees Celsius) for 1 hour; and
    (d) Conditioning the tubing assembly in air at minus 40 degrees 
Fahrenheit (minus 40 degrees Celsius) for 24 hours with atmospheric 
pressure inside the tubing assembly; and

[[Page 76333]]

    (e) Increasing the pressure inside the tubing assembly to 450 psi, 
and holding this pressure for five minutes while maintaining an air 
temperature of minus 40 degrees Fahrenheit (minus 40 degrees Celsius). 
(S12.23)
    S11.3.23 End fitting serviceability. A plastic air brake end 
fitting that uses a threaded retention nut shall not rupture or leak 
more than 25 cm3 per minute when pressurized to 120 psi 
after five assembly cycles. (S12.24)
    S11.3.24 End fitting corrosion resistance. After 24 hours of 
exposure to salt spray, air brake hose end fittings shall show no base 
metal corrosion on the end fitting surface except where crimping or the 
application of labeling information causes a displacement of the 
protective coating. (S12.25)
    S12. Test procedures--Plastic air brake tubing, plastic air brake 
tubing assemblies, plastic air brake tubing end fittings.
    S12.1 Air brake tubing dimensions. Measure the tubing dimensions 
including wall thickness, inside diameter, and outside diameter, using 
appropriate metrology apparatus such as micrometers, dial indicators 
and gauges, or optical comparators. To account for slight out-of-round 
conditions, diameter measurements may be calculated using the average 
of the major and minor diameters.
    S12.2 Constriction test. Perform the constriction test in S6.12 
using an air brake tubing assembly, except that the spherical diameter 
``A'' of the plug gauge in Figure 4, or the diameter of the rigid 
spherical ball in S6.12.3(a), shall be 66 percent of the nominal inside 
diameter of the tubing as specified in Table VII.
    S12.3 High temperature conditioning and dimensional stability test. 
(a) Condition the tubing at 230 degrees Fahrenheit (110 degrees 
Celsius) for 4 hours in an air oven.
    (b) Remove the tubing from the oven and allow to cool at room 
temperature for 30 minutes.
    (c) Measure the dimensions of the tubing using the procedure in 
S12.1.
    S12.4 Boiling water conditioning and dimensional stability test. 
(a) Utilize a container constructed of a non-reactive material large 
enough so that the tubing to be tested does not touch any surface of 
the container. Fill container with distilled water.
    (b) Slip the tubing over a stainless steel wire for positioning it 
in the pot.
    (c) Bring the water to a boil. Place the tubing in the water and 
position it so that it does not touch the container. Boil the tubing 
for two hours. Replenish the water as necessary, adding it slowly so 
that the water in the pot boils continuously.
    (d) Remove the tubing from the water and allow to cool at room 
temperature for 30 minutes. Wipe off any water that remains on the 
tubing.
    (e) Measure the dimensions of the tubing using the procedure in 
S12.1.
    S12.5 Burst strength test. (a) Utilize an air brake tubing assembly 
or prepare a 12 inch length of tubing and install end fittings 
according to the end fitting manufacturer's instructions.
    (b) Plug one end of the assembly, fill it with water, and connect 
the other end to a source of water pressure. Bleed any air from the 
assembly and water pressure system.
    (c) Increase the water pressure inside the tubing assembly at a 
rate of 3,000 psi per minute to the burst strength pressure for the 
size of tubing being tested as specified in Table VIII.
    S12.6 Moisture absorption and burst strength. (a) Prepare a sample 
of tubing twelve inches in length.
    (b) Condition the tubing at 230 degrees Fahrenheit (110 degrees 
Celsius) for 24 hours in an air oven. Remove the tubing from the oven 
and within 30 seconds, and weigh it to establish the initial weight. 
The weight shall be measured with a resolution of 0.01 gram; if the 
scale has a higher resolution, then values of 0.005 gram and above 
shall be rounded to the nearest 0.01 gram and values below 0.005 gram 
shall be truncated.
    (c) Place the tubing in an environmental chamber and condition it 
for 100 hours at 100 percent relative humidity and a temperature of 75 
degrees Fahrenheit (24 degrees Celsius).
    (d) Remove the tubing from the chamber and within a period of 5 
minutes, remove all surface moisture from the tubing using cloth and 
weigh the tubing to establish the conditioned weight. Weight shall be 
measured to the nearest 0.01 gram as in S12.6(b).
    (e) Calculate percentage of moisture absorption as follows:

([Conditioned Weight-Initial Weight]) [Initial Weight] x 100

    (f) Install end fittings according to the end fitting manufacturers 
instructions.
    (g) Conduct the burst strength test in 12.5 except use 80 percent 
of the burst strength pressure for the size of tubing being tested as 
specified in Table VIII.
    S12.7 Ultraviolet light resistance test. (a) Apparatus. An 
accelerated weathering test machine for ultraviolet light conditioning 
of plastic air brake tubing. The machine shall be equipped with 
fluorescent UVA-340 light bulbs and automatic irradiance control. Also 
utilize an impact test apparatus as shown in Figure 8.
    (b) Test standards. The testing is in accordance with American 
Society for Testing and Materials (ASTM) G154-00 ``Standard Practice 
for Operating Fluorescent Light Apparatus for UV Exposure of 
Nonmetallic Materials;'' ASTM G151-97 ``Standard Practice for Exposing 
Nonmetallic Materials in Accelerated Test Devices that Use Laboratory 
Light Sources,'' and; ASTM D4329-99 ``Standard Practice for Fluorescent 
UV Exposure of Plastics.'' These incorporations by reference were 
approved by the Director of the Federal Register in accordance with 5 
U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from the 
American Society for Testing and Materials (ASTM) International, 100 
Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959. 
Copies may be inspected at the National Highway Traffic Safety 
Administration, Technical Information Services, 400 Seventh St., SW., 
Plaza Level, Room 403, Washington, DC 20590, or at the National 
Archives and Records Administration (NARA). For information on the 
availability of this material at NARA, call (202) 741-6030, or go to: 
http://www.archives.gov/federal_register/code_of_federal 
regulations/ibr--locations.html.
    (c) Preparation. (1) Utilize a 12 inch length of plastic air brake 
tubing. Mask 1 inch of each end of the tubing where end fittings will 
be attached using opaque tape.
    (2) Attach the tubing to the test rack of the machine, securing it 
at the ends along the masked sections. Wipe the outside surface of the 
tubing with acetone to remove any surface contaminants. Place the 
tubing and rack in the accelerated weathering test machine so that the 
center of the tubing assembly is approximately in the center of the UV 
light exposure area of the test machine. (If multiple plastic brake 
tubing assemblies are tested, then their position in the machine should 
be rotated according to ASTM D4329-99 S7.4.1, except the rotation shall 
be each 96 hours instead of weekly.) The distance from the light bulb 
to the tubing shall be approximately 2 inches. Set the UV irradiance to 
0.85 watts per square meter at 340 nm and maintain this level during 
the testing. Maintain a temperature inside the test chamber of 113 
degrees Fahrenheit (45 degrees Celsius), and use only atmospheric 
humidity. Expose the tubing at this UV irradiance level for 300 hours 
continuously. Remove the tubing from the test chamber.
    (3) Place the tubing inside the impact test apparatus, and drop the 
impacter onto the tubing from a height of 12 inches.

[[Page 76334]]

    (4) Remove the masking material from the ends of the tubing. 
Install end fittings according to the end fitting manufacturer's 
instructions. Conduct the burst strength test in S12.5 except use 80 
percent of the burst strength pressure for the size of tubing being 
tested as specified in Table VIII.
BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TR20DE04.007


                       Table Accompanying Figure 8
------------------------------------------------------------------------
                                                          Hole diameter
                                                              ``D''
            Nominal tubing outside diameter            -----------------
                                                           mm     Inches
------------------------------------------------------------------------
\1/8\ inch............................................     3.96    0.156
\5/32\ inch...........................................     4.75    0.187
\3/16\ inch...........................................     5.54    0.218
\1/4\ inch............................................     7.14    0.281
\5/16\ inch...........................................     8.71    0.343
\3/8\ inch............................................    10.31    0.406
\1/2\ inch............................................    13.49    0.531
\5/8\ inch............................................    16.66    0.656
\3/4\ inch............................................    20.32    0.800
6 mm..................................................     6.80    0.268
8 mm..................................................     8.80    0.346
10 mm.................................................    10.80    0.425
12 mm.................................................    12.80    0.504
16 mm.................................................    16.80    0.661
------------------------------------------------------------------------

    S12.8 Low temperature flexibility test. (a) Utilize a cylinder 
having a radius of six times the nominal outside diameter of the 
tubing.
    (b) Condition the tubing in an air oven at 230 degrees Fahrenheit 
(110 degrees Celsius) for 24 hours. Remove from the oven and cool at 
room temperature for 30 minutes.
    (c) Condition the cylinder and the tubing in an environmental 
chamber at minus 40 degrees Fahrenheit (minus 40 degrees Celsius) for 
four hours.
    (d) With the tubing and test cylinder at minus 40 degrees 
Fahrenheit (minus 40 degrees Celsius), bend the tubing 180 degrees 
around the cylinder at a steady rate in a period of 4 to 8 seconds.
    S12.9 High temperature flexibility test. (a) Utilize a cylinder 
having a radius equal to the supported bend radius in Table VIII for 
the size of tubing being tested.

[[Page 76335]]

    (b) Bend the tubing 180 degrees around the cylinder and hold in 
place with a clamp or other suitable support, applying only enough 
force on the tubing to hold it in position.
    (c) Condition the tubing and cylinder in an air oven at 230 degrees 
Fahrenheit (110 degrees Celsius) for 72 hours. Remove the tubing and 
cylinder from the oven and cool at room temperature for two hours.
    (d) Remove the clamps or supports from the tubing and straighten 
the tubing at a steady rate in a period of 4 to 8 seconds.
    (e) Rebend the tubing 180 degrees around the cylinder, at the same 
point but in the opposite direction of the bending in S12.9(b), at a 
steady rate in a period of 4 to 8 seconds.
    (f) Conduct the burst strength test in S12.5 except use 80 percent 
of the burst strength pressure for the size of tubing being tested as 
specified in Table VIII.
    S12.10 High temperature resistance test. Condition the tubing in an 
air oven at 230 degrees Fahrenheit for 72 hours. Remove the tubing and 
allow to cool at room temperature for 30 minutes. Conduct the burst 
strength test in S12.5 except use 80 percent of the burst strength 
pressure for the size of tubing being tested as specified in Table 
VIII.
    S12.11 High temperature conditioning, low temperature impact 
resistance test. (a) Apparatus. Utilize an impact test apparatus as 
shown in Figure 8.
    (b) Condition the tubing in an air oven at 230 degrees Fahrenheit 
(110 degrees Celsius) for 72 hours. Remove the tubing and allow to cool 
at room temperature for 30 minutes.
    (c) Condition the tubing and the impact test apparatus in an 
environmental chamber at minus 40 degrees Fahrenheit (minus 40 degrees 
Celsius) for 4 hours.
    (d) With the tubing and impact test apparatus at minus 40 degrees 
Fahrenheit (minus 40 degrees Celsius), place the tubing inside the 
apparatus and drop the impacter onto the tubing from a height of 12 
inches. Remove the tubing from the chamber and allow to warm at room 
temperature for one hour.
    (e) Conduct the burst strength test in S12.5 except use 80 percent 
of the burst strength pressure for the size of tubing being tested as 
specified in Table VIII.
    S12.12 Boiling water conditioning, low temperature impact 
resistance test. (a) Apparatus. Utilize an impact test apparatus as 
shown in Figure 8.
    (b) Condition the tubing in boiling water using the test in S12.4 
(a) through (d), except that the length of tubing shall be 12 inches.
    (c) Condition the tubing and the impact test apparatus in an 
environmental chamber at minus 40 degrees Fahrenheit (minus 40 degrees 
Celsius) for 4 hours.
    (d) With the tubing and impact test apparatus at minus 40 degrees 
Fahrenheit (minus 40 degrees Celsius), place the tubing inside the 
apparatus and drop the impacter onto the tubing from a height of 12 
inches. Remove the tubing from the chamber and allow to warm at room 
temperature for one hour.
    (e) Conduct the burst strength test in S12.5 except use 80 percent 
of the burst strength pressure for the size of tubing being tested as 
specified in Table VIII.
    S12.13 Zinc chloride resistance test. (a) Utilize a cylinder having 
a radius equal to the supported bend radius in Table VIII for the size 
of tubing being tested. The cylinder is constructed of a non-reactive 
material or coated to prevent chemical reaction with zinc chloride. The 
length of the tubing sample is long enough so that its ends will not be 
submerged during the immersion in zinc chloride, or the ends of the 
tubing are plugged to keep the zinc chloride from entering the tubing.
    (b) Bend the tubing 180 degrees around the cylinder and hold in 
place with a clamp or other suitable support constructed of non-
reactive materials, applying only enough force on the tubing to hold it 
in position.
    (c) Immerse the tubing and cylinder in a 50 percent zinc chloride 
aqueous solution at room temperature for 200 hours.
    (d) Remove the tubing and cylinder from the solution. While still 
on the test cylinder, inspect the tubing under 7-power magnification 
for cracks.
    S12.14 Methyl alcohol resistance. (a) Utilize a cylinder having a 
radius equal to the supported bend radius in Table VIII for the size of 
tubing being tested. The cylinder is constructed of a non-reactive 
material or coated to prevent chemical reaction with methyl alcohol.
    (b) Bend the tubing 180 degrees around the cylinder and hold in 
place with a clamp or other suitable support constructed of non-
reactive materials, applying only enough force on the tubing to hold it 
in position. The ends of the tubing may be shortened so that they will 
be fully submerged in the methyl alcohol.
    (c) Immerse the tubing and cylinder in a 95 percent methyl alcohol 
aqueous solution at room temperature for 200 hours.
    (d) Remove the tubing and cylinder from the solution. While still 
on the test cylinder, inspect the tubing under 7-power magnification 
for cracks.
    S12.15 High temperature conditioning and collapse resistance test. 
(a) Apparatus. A holding device consisting of two vertical pins affixed 
to a flat, horizontal plate. Each pin projects 1 inch above the top 
surface of the plate. The diameter of each pin is approximately equal 
to the inside diameter of the tubing being tested. Using the 
unsupported bend radius for the size of tubing being tested from Table 
VIII, the distance between the pin centerlines is equal to:

[2 x unsupported bend radius] + [nominal OD of tubing]

    (b) Preparation. (1) Use the unsupported bend radius for the size 
of tubing being tested from Table VIII and cut the tubing to the 
following length:

[3.14 x [unsupported bend radius]] + [10 x [nominal tubing OD]] + 2 
inches

    or

[3.14 x [unsupported bend radius]] + [10 x [nominal tubing OD]] + 50 mm

    (2) Place a reference mark at the center of the sample. At this 
mark, measure the initial outside diameter of the tubing. If the tubing 
is slightly out-of-round, use the elliptical minor diameter as the 
initial outside diameter.
    (3) Install the tubing completely over the pins of the holding 
device so that the tubing is bent 180 degrees. If the tubing has a 
natural curvature, the tubing shall be bent in the direction of the 
natural curvature.
    (4) Condition the holding device and tubing in an air oven at 230 
degrees Fahrenheit (110 degrees Celsius) for 24 hours. Remove the 
holding device and tubing and allow to cool at room temperature for 
thirty minutes.
    (5) With the tubing still mounted to the holding device, measure 
the elliptical minor diameter of the tubing at the reference mark to 
determine the final outside diameter.
    (c) Calculation. Calculate the percentage collapse of the outside 
diameter of the tubing as follows:

([Initial Outside Diameter - Final Outside Diameter]) [Initial Outside 
Diameter] x 100

    S12.16 Ozone resistance test. Conduct the test specified in S6.8 
using plastic air brake tubing.
    S12.17 Oil resistance test. (a) Utilize a plastic air brake tubing 
assembly or prepare a 12 inch length of tubing and install end fittings 
according to the end fitting manufacturer's instructions.
    (b) Immerse the tubing assembly in ASTM 903 oil at 212 degrees 
Fahrenheit (100 degrees Celsius) for 70 hours. Remove and allow to cool 
at room temperature for 30 minutes. Wipe any excess oil from the tubing 
assembly.

[[Page 76336]]

    (c) Conduct the burst strength test in S12.5 except use 80 percent 
of the burst strength pressure for the size of tubing being tested as 
specified in Table VIII and, at the manufacturer's option, oil may be 
used as the test medium instead of water.
    S12.18 Tensile strength test. Conduct the test in S8.9 using a 
plastic air brake tubing assembly or an assembly prepared from a 12 
inch length of air brake tubing with end fittings installed according 
to the end fitting manufacturer's instructions.
    S12.19 Boiling water conditioning and tensile strength. (a) 
Apparatus. Use a tension testing machine as specified in S8.9. The 
lower attachment point of the machine is equipped with a heated, open-
top container that is water tight. The inside of the container (lower 
attachment point) and upper attachment point of the machine have 
provisions to quickly attach a brake hose assembly for tensile testing.
    (b) Preparation. Prepare an air brake tubing assembly with a free 
length of 6 inches (six inches of exposed tubing between the end 
fittings), with the end fittings installed in accordance with the end 
fitting manufacturer's instructions. If necessary install adapters on 
the end fittings to permit quick attachment to the machine, to keep 
water from entering the tubing assembly, and to ensure that the tubing 
assembly is in a straight position when installed on the machine. Fill 
the container with distilled water such that the lower 4 inches of 
exposed tubing will be submerged when the brake tubing assembly is 
installed on the machine. Heat the water until it boils. Then quickly 
install the plastic air brake tubing assembly on the machine with the 
lower end of the tubing assembly in the boiling water. After the water 
has boiled continuously for 5 minutes, apply tension to the tubing 
assembly at a rate of 1 inch per minute travel of the moving head until 
either the conditioned tensile load in Table VIII for the size of 
tubing being tested is reached or the free length of the tubing 
assembly reaches 9 inches, whichever occurs first.
    S12.20 Thermal conditioning and tensile strength. (a) Apparatus. 
Use a tension testing machine as specified in S8.9.
    (b) Preparation. Prepare an air brake tubing assembly with a free 
length of 6 inches (six inches of exposed tubing between the end 
fittings), with the end fittings installed in accordance with the end 
fitting manufacturer's instructions. If necessary install adapters on 
the end fittings to permit attachment to the machine, to keep water 
from entering the tubing assembly, and/or to ensure that the tubing 
assembly is in a straight position when installed on the machine. 
Subject the tubing assembly to four complete cycles of the following 
sequence:
    (1) Condition the tubing assembly in an environmental chamber at 
minus 40 degrees Fahrenheit (minus 40 degrees Celsius) for 30 minutes. 
Remove from the chamber and allow to warm at room temperature for 30 
minutes.
    (2) Condition the tubing assembly by submerging it in boiling water 
for 15 minutes. Remove and allow to cool at room temperature for 30 
minutes. Install the tubing assembly on the tension testing machine and 
apply tension to the tubing assembly at a rate of one inch per minute 
travel of the moving head until either the conditioned tensile load in 
Table VIII for the size of tubing being tested is reached or the free 
length of the tubing assembly reaches 9 inches, whichever occurs first.
    S12.21 Vibration resistance test. (a) Apparatus. A vibration 
testing machine that supports a brake tubing assembly by its end 
fittings in approximately a straight line and includes the following 
features:
    (1) One tubing assembly attachment point is fixed and the other 
moves in a plane perpendicular to a line projected between the 
attachment points. The movable attachment point moves in a linear 
direction and travels \1/2\ inch total and at its midpoint of travel 
falls on a line projected between the attachment points. The movable 
attachment point has a cycle rate of 600 cycles per minute.
    (2) The distance between the attachment points is adjustable to 
compensate for varying lengths of brake tubing assemblies.
    (3) The actuating mechanism for the movable attachment point is 
balanced to prevent introduction of machine vibration into the brake 
tubing assembly.
    (4) The machine has a compressed air supply system that pressurizes 
the air brake tubing assembly through one fitting while the other 
fitting is plugged. The machine's compressed air supply system includes 
a pressure gauge or monitoring system and an air flow meter.
    (5) The machine is constructed so that an air brake tubing assembly 
mounted on it can be conditioned in an environmental test chamber.
    (b) Preparation. (1) Prepare an air brake tubing assembly with a 
free length of 18 inches (18 inches of exposed tubing between the end 
fittings), with the end fittings installed in accordance with the end 
fitting manufacturer's instructions. Record the initial tightening 
torque for an end fitting that uses a threaded retaining nut.
    (2) Install the air brake tubing assembly on the vibration testing 
machine and, with the movable attachment point at the midpoint of its 
travel, adjust the distance between the attachment points so that they 
are \1/2\ inch closer together than the distance at which the tubing 
assembly is taut.
    (3) With the tubing assembly inside the environmental chamber, 
apply compressed air to the tubing assembly at a regulated pressure of 
120 psi and maintain the supply of air to the tubing assembly for the 
duration of the test. Set the temperature of the environmental chamber 
to 220 degrees Fahrenheit (104 degrees Celsius) and initiate cycling of 
the movable attachment point. After 250,000 cycles, set the temperature 
of the environmental chamber to minus 40 degrees Fahrenheit (minus 40 
degrees Celsius). After 500,000 cycles, set the temperature of the 
environmental chamber to 220 degrees Fahrenheit (104 degrees Celsius). 
After 750,000 cycles, set the temperature of the environmental chamber 
to minus 40 degrees Fahrenheit (minus 40 degrees Celsius). Measure the 
air flow rate just prior to 1,000,000 cycles and if the compressed air 
flow rate supplied to the air brake tubing assembly exceeds 50 cubic 
centimeters per minute this constitutes failure of the test. Stop the 
cycling at 1,000,000 cycles and set the environmental chamber 
temperature to 75 degrees Fahrenheit (24 degrees Celsius), while air 
pressure is still supplied to the air brake tubing assembly. After one 
hour, measure the compressed air flow rate supplied to the air brake 
tubing assembly and if the rate exceeds 25 cubic centimeters per minute 
this constitutes failure of the test.
    (4) For end fittings that use a threaded retaining nut, apply 20 
percent of the original tightening torque as recorded in S12.21(b)(1). 
If the retention nut visibly moves, this constitutes a failure of the 
test.
    S12.22 End fitting retention test. (a) Utilize an air brake tubing 
assembly or prepare a 12 inch length of tubing and install end fittings 
according to the end fitting manufacturer's instructions.
    (b) Plug one end of the assembly, fill it with water, and connect 
the other end to a source of water pressure. Bleed any air from the 
assembly and water pressure system.
    (c) Increase the pressure inside the tubing assembly at a rate of 
3,000 psi per minute to 50 percent of the burst strength pressure for 
the size of tubing being tested as specified in Table VIII.

[[Page 76337]]

Hold the pressure constant for 30 seconds.
    (d) Increase the pressure inside the tubing assembly at a rate of 
3,000 psi per minute to the burst strength pressure for the size of 
tubing being tested as specified in Table VIII.
    S12.23 Thermal conditioning and end fitting retention test. (a) 
Apparatus. A source of hydraulic pressure that includes a pressure 
gauge or monitoring system, uses ASTM IBM 903 oil, and is constructed 
so that an air brake tubing assembly mounted to it can be conditioned 
in an environmental test chamber.
    (b) Preparation. Utilize an air brake tubing assembly or prepare a 
12 inch length of tubing and install end fittings according to the end 
fitting manufacturer's instructions. Attach one end of the assembly to 
the hydraulic pressure supply and plug the other end of the assembly, 
fill the assembly with ASTM IRM 903 oil and bleed any air from the 
assembly, and place the tubing assembly inside an environmental 
chamber. Conduct the following tests:
    (1) With atmospheric pressure applied to the oil inside the tubing 
assembly, set the environmental chamber temperature to 200 degrees 
Fahrenheit (93 degrees Celsius) and condition the tubing assembly for 
24 hours.
    (2) With the temperature maintained at 200 degrees Fahrenheit (93 
degrees Celsius), increase the oil pressure inside the tubing assembly 
at a rate of 3,000 psi per minute to 450 psi, and hold this pressure 
for 5 minutes.
    (3) Decrease the oil pressure inside the tubing assembly at a rate 
of 3,000 psi per minute to atmospheric pressure and set the temperature 
of the environmental chamber to 75 degrees Fahrenheit (24 degrees 
Celsius). Condition the tubing assembly at this temperature for 1 hour.
    (4) Set the temperature of the environmental chamber to minus 40 
degrees Fahrenheit (minus 40 degrees Celsius) and condition the tubing 
assembly for 24 hours.
    (5) With the temperature maintained at minus 40 degrees Fahrenheit 
(minus 40 degrees Celsius), increase the hydraulic pressure inside the 
tubing assembly at a rate of 3,000 psi per minute to 450 psi, and hold 
this pressure for 5 minutes.
    S12.24 End fitting serviceability. (a) Apparatus. A source of air 
pressure that includes a pressure gauge or monitoring system and is 
equipped with a mass air flow meter.
    (b) Preparation. Prepare a 12-inch length of tubing and plug one 
end. Assemble the end fitting with the threaded retention nut on the 
other end of the tubing according to the end fitting manufacturer's 
instructions, then disassemble the fitting. Repeat the assembly and 
disassembly sequence three more times, and then reassemble the end 
fitting (five total assembly steps).
    (c) Attach the end fitting with the threaded retention nut to the 
source of air pressure. Pressurize the tubing at a rate of 3,000 psi 
per minute to a pressure of 120 psi. If the end fitting leaks, measure 
and record the leakage rate using the mass air flow meter.
    S12.25 End fitting corrosion resistance. Utilize an air brake 
tubing assembly or prepare a 12-inch length of tubing and install end 
fittings according to the end fitting manufacturer's instructions. 
Conduct the test specified in S6.11 using a plastic air brake tubing 
assembly.
    S13. Test Conditions. Each hose assembly or appropriate part 
thereof shall be able to meet the requirements of S5, S7, S9, and S11, 
under the following conditions.
    S13.1 The temperature of the testing room is 75 degrees Fahrenheit 
(24 degrees Celsius).
    S13.2 The brake hoses and brake hose assemblies are at least 24 
hours old, and unused.
    S13.3 Specified test pressures are gauge pressures (psig).

    Issued on: December 3, 2004.
Jeffrey W. Runge,
Administrator.
[FR Doc. 04-27088 Filed 12-17-04; 8:45 am]
BILLING CODE 4910-59-P