[Federal Register Volume 68, Number 94 (Thursday, May 15, 2003)]
[Proposed Rules]
[Pages 26384-26424]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-11292]



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Part II





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; Proposed Rule

  Federal Register / Vol. 68, No. 94 / Thursday, May 15, 2003 / 
Proposed Rules  

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. 03-14483, No. 1]
RIN 2127-AH79


Federal Motor Vehicle Safety Standards; Brake Hoses

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

ACTION: Notice of proposed rulemaking.

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SUMMARY: Pursuant to the agency's grant of a joint petition from Elf 
Atochem North America, Inc., Mark IV Industrial/Dayco Eastman, and 
Parker Hannifin Corporation, NHTSA proposes to update 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, and plastic air brake tubing.

DATES: Comments must be received on or before July 14, 2003.

ADDRESSES: Comments should refer to the docket number above and be 
submitted to: Docket Section, National Highway Traffic Safety 
Administration, 400 Seventh Street, SW, Washington, DC 20590. 
Alternatively, you may submit your comments electronically by logging 
onto the Docket Management System (DMS) Web site at http://dms.dot.gov. 
Click on ``Help & Information'' or ``Help/Info'' to view instructions 
for filing your comments electronically. Regardless of how you submit 
your comments, you should mention the docket number of this document.
    You may call the Docket at 202-366-9324. Docket hours are 9:30 a.m. 
to 4 p.m., Monday through Friday.

FOR FURTHER INFORMATION CONTACT: For non-legal issues, Mr. Jeffrey 
Woods, Vehicle Dynamics Division, Office of Vehicle Safety Standards 
(Telephone: 202-366-6206) (Fax: 202-366-4921). Mr. Woods' mailing 
address is National Highway Traffic Safety Administration/DOT, NPS-22, 
400 Seventh St., SW., Washington, DC 20590.
    For legal issues, Mr. George Feygin, Office of the Chief Counsel 
(Telephone: 202-366-2992) (Fax: 202-366-3820). Mr. Feygin's mailing 
address is National Highway Traffic Safety Administration, NCC-20, 400 
Seventh St., SW., Washington, DC 20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Background
II. Joint Petition for Rulemaking
III. Summary of Response to Petition
IV. NHTSA's Proposed Revisions to FMVSS No. 106
    A. Hydraulic Brake Hoses
    1. Pressure Test
    2. Constriction
    3. Volumetric Expansion
    4. Whip Resistance Test
    5. Tensile Strength
    6. Water Absorption and Pressure Test, Tensile Strength, and 
Whip Resistance
    7. Low temperature Resistance Test
    8. Brake Fluid Compatibility, Constriction, and Burst Strength
    9. Ozone Resistance
    10. End Fitting Corrosion Resistance
    11. High Temperature Impulse Test
    B. Air Brake Hoses
    1. Dimensional Requirements
    2. Construction and Labeling
    3. Manufacturer Identification
    4. Constriction
    5. High Temperature Resistance
    6. Low Temperature Resistance
    7. Oil Resistance
    8. Ozone Resistance
    9. Length Change
    10. Adhesion
    11. Air Pressure (leakage)
    12. Burst Strength
    13. Tensile Strength
    14. Water Absorption and Tensile Strength
    15. Zinc Chloride Resistance
    16. End Fitting Corrosion Resistance
    17. Minimum Bend Radius
    C. Vacuum Brake Hoses
    1. Constriction
    2. High Temperature Resistance
    3. Low Temperature Resistance
    4. Ozone Resistance
    5. Burst Strength
    6. Vacuum Deformation
    7. Bend Test
    8. Swell (Fuel Resistance)
    9. Adhesion
    10. Deformation
    11. End Fitting Corrosion Resistance
    D. Plastic Air Brake Tubing
    1. Classification
    2. Dimensions and Tolerances
    3. One Hundred Percent Leak Test
    4. Burst Test
    5. Moisture Absorption
    6. Ultraviolet Resistance
    7. Cold temperature Flexibility
    8. Heat Aging
    9. Zinc Chloride Resistance
    10. Methyl Alcohol Resistance
    11. Stiffness
    12. Boiling Water Stabilization and Burst Test
    13. Cold Temperature Impact
    14. Adhesion
    15. Heat Aging and Adhesion Test
    16. Collapse Resistance
    17. Oil Resistance
    18. Ozone Resistance
    E. Plastic Air Brake Tubing Assemblies and End Fittings
    1. Tensile Strength
    2. Hot Tensile Strength
    3. Conditioned Pull Test
    4. Vibration Leak Test
    5. Proof and Burst Test
    6. Serviceability Test
    7. Fitting Compatibility Test
    8. Constriction
    9. End Fitting Dimensional Requirements
10. End Fitting Corrosion Resistance
V. 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 (RIN)
    K. Comments

I. Background

    This document responds to a joint petition for rulemaking filed on 
October 30, 1998, by Elf Atochem North America, Inc., Mark IV 
Industrial/Dayco Eastman, and Parker Hannifin Corporation, three brake 
hose manufacturers. The petitioners request 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 currently administered by the National Highway Traffic Safety 
Administration (``NHTSA'' or the ``agency''). Specifically, the 
petitioners request incorporation of the requirements in Sec.  393.45 
(Brake tubing and hose, adequacy) and Sec.  393.46 (Brake tubing and 
hose connections) of the Federal Motor Carrier Safety Regulations 
(FMCSR) into Sec.  571.106 (Brake hoses) of the Federal motor vehicle 
safety standards (``FMVSS'').
    Sections 393.45 and 393.46 of the FMCSRs require that brake hose, 
tubing, and fittings on ``commercial motor vehicles'' be maintained 
according to certain specifications adopted by the Society of 
Automotive Engineers (``SAE''). A ``commercial motor vehicle'' is 
defined, in Sec.  393.5 of the FMCSRs, as

 any self-propelled or towed motor vehicle used on a highway in 
interstate commerce to transport passengers or property when the 
vehicle--

    (1) Has a gross vehicle weight rating or gross combination 
weight rating, or gross vehicle weight or gross combination weight, 
of 4,537 kg (10,001 lbs.) or more; whichever is greater; or
    (2) Is designed or used to transport more than 8 passengers 
(including the driver) for compensation; or
    (3) Is designed or used to transport more than 15 passengers, 
including the driver, and is not used to transport passengers for 
compensation; or

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    (4) Is used in transporting material found by the Secretary of 
Transportation to be hazardous under 49 U.S.C. 5103 and transported 
in a quantity requiring placarding under regulations prescribed by 
the Secretary under 49 CFR, subtitle B, chapter I, subchapter C.\1\
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    \1\ The FMCSRs contain two different definitions of ``commercial 
motor vehicle': one in Sec.  393.5 and another in section 382.107. 
The latter definition is narrower than the former. We note that all 
references throughout this document to ``commercial motor vehicle'' 
are to the broader definition found in section 393.5.

    Pursuant to Sec.  393.45, brake tubing and hose on commercial motor 
vehicles must conform to the following SAE specifications: SAE 
Recommended Practice J1149 (Metallic Air Brake System Tubing and Pipe--
July 1976); SAE Recommended Practice J844 (Nonmetallic Air Brake System 
Type B--October 1980); SAE Recommended Practice J1402 (Automotive Air 
Brake Hose and Hose Assemblies--June 1985); SAE Recommended Practice 
J1401 (Road Vehicle Hydraulic Brake Hose Assemblies for Use with Non 
Petroleum Base Hydraulic Fluid--June 1985); and SAE Recommended 
Practice J1403 (Vacuum Brake Hose--June 1985). Under section 393.46, 
tube fittings on commercial motor vehicles must conform to the 
requirements of either SAE Standard J512 (Automotive Tube Fittings--
October 1980) or SAE J246 (Spherical and Flanged Sleeve (Compression) 
Tube Fittings--March 1981).
    The Federal Highway Administration (``FHWA''), which was 
responsible for administering the FMCSRs prior to the formation of the 
Federal Motor Carrier Safety Administration, issued a Notice of 
Proposed Rulemaking on April 14, 1997 (62 FR 18170). The FHWA proposed 
amending part 393 of the FMSCRs to, among other things, remove obsolete 
and redundant regulations and resolve inconsistencies between part 393 
and NHTSA's FMVSS. 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 
with FMVSS No. 106.
    Accordingly, FHWA's NPRM included a proposal to delete from 
Sec. Sec.  393.45 and 393.46 all but one of the references to SAE 
specifications applicable to metallic brake tubing, nonmetallic brake 
tubing, air brake hose, hydraulic brake hose, vacuum brake hose, air 
brake tube fittings, and spherical and flanged sleeve tube fittings. In 
place of the SAE specifications, FHWA proposed that Sec.  393.45 state 
that all brake hose and tubing, brake hose assemblies, and fittings 
must meet the applicable requirements of FMVSS No. 106. The proposal 
included retaining one reference to SAE J844 in Sec.  393.45 for coiled 
nylon brake hose and hose assemblies. Presently, FMVSS No. 106 excludes 
coiled nylon brake hose/assemblies that comply with FMCSR Sec.  393.45 
from certain requirements, namely S7.3.6 (length change), S7.3.10 
(tensile strength), and S7.3.11 (tensile strength of an assembly after 
immersion in water).
    FHWA's NPRM aroused concerns. Several brake hose manufacturers and 
one engineering consultant submitted comments objecting to the proposed 
deletion of all but one reference to the SAE specifications from 
Sec. Sec.  393.45 and 393.46 of the FMCSRs. In addition, a letter 
signed by 44 Members of Congress was sent to the Secretary of 
Transportation on November 3, 1997, expressing their concern over 
FHWA's proposal to repeal its safety standards for commercial motor 
vehicle brake hose, brake tubing, and fittings.
    In response to these concerns, the Department of Transportation 
held a public meeting on March 24, 1998. In attendance were 
representatives from FHWA and NHTSA, several brake hose/tubing/fitting 
manufacturers, a truck manufacturer, a truck manufacturers association, 
an explosives manufacturer, a truck users association, and United 
States Congressman Thomas Sawyer (D-Ohio).
    At the public meeting, 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 
for the FMCSRs be incorporated into FMVSS No. 106.

II. Joint Petition for Rulemaking

    On October 30, 1998, Elf Atochem North America, Inc., Mark IV 
Industrial/Dayco Eastman, and Parker Hannifin Corporation jointly 
submitted a petition for rulemaking asking the agency to incorporate 
into FMVSS No. 106 the SAE specifications for brake hose, brake tubing, 
and fittings that FHWA proposed deleting from Sec. Sec.  393.45 and 
393.46 of the FMCSRs. The petition 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 lbs. 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.

III. NHTSA's Response to the Joint Petition

    NHTSA has decided to grant the joint petition for rulemaking. The 
agency agrees with the petitioners that there is a safety need to 
transfer the brake hose, tubing, and fitting requirements currently 
contained in Sec. Sec.  393.45 and 393.46 of the FMCSRs to FMVSS No. 
106, before those requirements are deleted. NHTSA tentatively concludes 
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 as noted. This would involve, among other changes, 
establishing a new category in the standard for plastic air brake 
tubing, end fittings, and tubing assemblies.
    NHTSA's decision to grant the joint petition is also based on the 
fact that FMVSS No. 106 has not been substantially updated in many 
years. Revisions over the past 20 years have primarily addressed 
labeling issues, inclusion of metric-sized brake hoses, updating test 
fluids to match advances in industry, and minor regulatory revisions to 
individual test conditions such as the whip test and the adhesion test. 
The agency notes that most of the substantive requirements currently in 
Standard 106, other than the labeling requirements, 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 Standard No. 106 would take into account the substantial 
technological developments that have occurred and align the

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standard's requirements with standard industry practices. Incorporating 
many of the SAE standard's 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 Public Law 104-113, the ``National 
Technology Transfer and Advancement Act of 1995.''
    The agency's proposal differs in a number of respects, however, 
from that requested by the petitioners--
    First, as explained in greater detail below, instead of simply 
incorporating complete SAE standards by reference as the FMCSRs 
currently do, NHTSA proposes to incorporate only the specific 
requirements/specifications of the SAE standards that are either more 
rigorous than those in Standard No. 106 or are not present at all in 
FMVSS No. 106.
    Second, the agency does not propose to limit the application of 
those SAE requirements/specifications to brake hose, tubing, and 
fittings used on commercial motor vehicles. NHTSA tentatively concludes 
that all brake hose, tubing, and fittings can and should meet the 
requirements/specifications, regardless of their end use.
    Third, although NHTSA agrees 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 notes that a number of SAE's standards have been updated 
since the joint petition was filed. Accordingly, NHTSA proposes to rely 
on the most recent versions of the SAE standards.
    Fourth, the agency does not propose to incorporate SAE standards 
relating to copper tubing, galvanized steel pipe, or end fittings used 
with metallic or non-metallic tubing because these materials are 
occasionally used in chassis plumbing and these products are not 
considered to be brake hoses, thus it would not be appropriate to 
include them in FMVSS No. 106.
    Fifth, NHTSA is not proposing 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 
concludes that incorporating those material specifications would be 
design-restrictive.
    Sixth, NHTSA does 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 concludes that the manufacturer identification requirements 
already present in FMVSS No. 106 are sufficient.

IV. Proposed Revisions to FMVSS No. 106

    The following sections describe the changes NHTSA proposes to make 
to Standard 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. Each section contains a table 
comparing the performance requirements and test procedures of FMVSS No. 
106 to the relevant SAE Recommended Practice/Standard and a 
requirement-by-requirement/procedure-by-procedure explanation of the 
changes NHTSA is proposing. Generally speaking, whenever an SAE 
specification is more stringent than the corresponding FMVSS No. 106 
requirement/procedure, NHTSA proposes to incorporate the SAE 
specification.

A. Hydraulic Brake Hoses

    NHTSA's performance requirements and test procedures relating to 
hydraulic brake hoses are located in paragraph S5., Requirements--
Hydraulic brake hose, brake hose assemblies, and brake hose end 
fittings, and paragraph S6., Test procedures--Hydraulic brake hose, 
brake hose assemblies, and brake hose end fittings of FMVSS No. 106. 
The corresponding SAE specifications are contained in SAE Surface 
Vehicle Standard J1401, Hydraulic Brake Hose Assemblies for Use with 
Nonpetroleum-Base Hydraulic Fluids, Rev. September 1999 (SAE J1401).
    The performance requirements and test procedures for hydraulic 
brake hoses in FMVSS No. 106 and SAE J1401 are similar, but not 
identical. In many cases, the requirements and procedures in SAE J1401 
are more stringent than the corresponding requirements and procedures 
in paragraphs S5 and S6 of FMVSS No. 106. For example, in recognition 
of the fact that underhood temperatures have increased in modern 
passenger cars and, therefore, front brake hoses near the engine 
compartment are subjected to these higher temperatures, SAE J1401 
recommends subjecting hydraulic brake hose to a hot impulse test. In 
contrast, FMVSS No. 106 does not specify a hot impulse test because 
many of the specifications in the standard originated in the late 
1960s, when underhood temperatures were lower.
    Generally, in those instances in which the performance requirements 
and test procedures in SAE J1401 are more rigorous, as with the hot 
impulse test specification, NHTSA is proposing to incorporate the SAE 
J1401 requirement/procedure. Where the requirements and procedures of 
FMVSS No. 106 are either more stringent or are not addressed at all in 
SAE J1401, however, the agency is proposing to retain the FMVSS No. 106 
requirement/procedure.
    The agency notes that because the reach of Sec.  393.45 of the 
FMCSRs is limited to ``commercial motor vehicles,'' the performance 
requirements and test procedures in SAE J1401 are, at present, only 
being applied to hydraulic brake hose in use on those vehicles. In 
contrast, FMVSS No. 106's requirements/procedures apply to all 
hydraulic brake hoses, regardless of their end use. One question that 
arises in connection with NHTSA's proposal to incorporate many of SAE 
J1401's specifications, therefore, is whether to restrict application 
of those specifications to hydraulic brake hoses designed for use on 
commercial motor vehicles. NHTSA proposes to apply the specifications 
of SAE J1401 to all hydraulic brake hoses, regardless of the type of 
vehicle on which it is installed. The agency does not favor the 
creation of a separate category of, for example, ``commercial'' 
hydraulic brake hoses that would include the more severe test 
conditions only for those particular brake hoses because NHTSA 
tentatively concludes that all types of brake hoses can and should meet 
the current SAE J1401 specifications.
    Many light vehicles, including passenger cars, are currently 
manufactured using brake hoses that meet SAE J1401 specifications or 
other, proprietary standards that are more severe than Standard 106. 
Although it is not clear whether replacement brake hoses are also 
designed to meet these more rigorous specifications, NHTSA tentatively 
concludes that it is in the interest of safety to specify that they do 
so. From a safety standpoint, if a replacement brake hose which does 
not meet SAE J1401 specifications were to be installed on a vehicle 
originally outfitted with hose designed to meet the specifications of 
SAE J1401 (or another proprietary standard more stringent than FMVSS 
No. 106), the vehicle brake hose would be more prone to failure. 
Requiring all hydraulic brake hoses, both original equipment 
manufacturer (OEM) brake hoses and replacement brake hoses, to meet the 
current SAE J1401 requirements/specifications

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should substantially decrease the likelihood of brake hose failure. 
NHTSA welcomes comments, however, regarding the appropriateness of 
applying SAE J1401's requirements/specifications to all hydraulic brake 
hoses, regardless of their end use or whether they are OEM hoses or 
replacement hoses.
    A detailed discussion of the differences between the hydraulic 
brake hose performance requirements and test procedures in SAE J1401 
and FMVSS No. 106 follows, along with the agency's proposed resolution 
of those differences.
1. Pressure Test
    SAE J1401 specifies a test pressure of 1,500 psi minimum and 2,100 
psi maximum for inert gas or air tests and 3,000 psi minimum and 3,500 
psi maximum for water and brake fluid tests, with the hose assembly 
required to sustain these pressures for 10 to 20 seconds, as a 
preconditioning test for all samples of hose assemblies to be subjected 
to further test conditions. The burst test (following the expansion 
test; see S5.3.2) specifies a minimum requirement of 4,000 psi plus 
zero (0) minus 200 psi for 2 minutes, using water or brake fluid, 
followed by a pressure increase to the point of failure. The minimum 
failure for \1/8\ inch hose is 7,000 psi and for \3/16\ hose is 5,000 
psi. SAE J1401 does not specify test conditions for hose sizes other 
than \1/8\ or \3/16\ inch.
    In contrast, FMVSS No. 106 specifies a water pressure test of 4,000 
psi for 2 minutes and 5,000 psi minimum burst strength. The performance 
requirements and test procedures are similar to those in SAE J1401, 
although FMVSS No. 106 includes a lower pressure requirement for \1/8\ 
hose (5,000 psi) and includes requirements for hose with inside 
diameters of \1/4\ inch or larger.
    NHTSA tentatively concludes that a higher, 7,000 psi burst strength 
requirement should be adopted for \1/8\ inch and 3mm hydraulic brake 
hoses. NHTSA contacted Intertek Testing Services, a company that has 
performed compliance testing of brake hoses under contract to the 
agency, to determine if the 7,000-psi pressure has been sustained by 
brake hoses in past testing. Intertek indicated that it typically will 
test up to 10,000 psi for all sizes of hydraulic brake hose, and that 
the hose have consistently been able to sustain this much pressure 
without bursting. Therefore, NHTSA proposes that the 7,000 psi burst 
strength requirement from SAE J1401 be adopted into Standard No. 106 
for \1/8\ inch and 3 mm hydraulic brake hoses.
2. Constriction
    SAE J1401's constriction requirement is limited to hydraulic brake 
hose with an internal hose diameter of \1/8\ inch or \3/16\ inch. SAE 
J1401 specifies a minimum pass-through diameter of 64 percent of 
nominal internal hose diameter, which is determined by performing a 
plug gage test. FMVSS No. 106 contains the same 64 percent of nominal 
internal hose diameter requirement, but applies it to hose of all 
sizes, not just hose with an internal hose diameter of \1/8\ inch or 
\3/16\ inch. Unlike SAE J1401, however, FMVSS No. 106 does not specify 
a test for determining hose's minimum pass-through diameter. In 
addition, FMVSS No. 106 explicitly excludes those portions of end 
fittings that do not contain hose from the constriction test while SAE 
J1401 does not. NHTSA welcomes comments on the issue of whether the 
constriction exclusion for portions of end fittings that do not contain 
hose is still necessary, or if there have been any substantial changes 
to brake systems which preclude the use of intentionally-restrictive 
end fittings.
    NHTSA proposes retaining the existing constriction performance 
requirement in FMVSS No. 106 and adding a constriction test procedure. 
Two different constriction test procedures are available: the drop-ball 
test and the plug gauge test. In the drop-ball test, a steel ball with 
a diameter equal to the minimum constriction diameter for a particular 
hose size is dropped into one end of the hose at its fitting. Gravity 
is the only downward force acting on the ball, and friction between the 
hose and ball may not be sufficiently overcome in all tests.
    As noted above, SAE J1401 specifies use of a plug gauge test. In 
the plug gauge test, a cylindrical plug with a small rod handle is 
inserted into and removed from the hose. NHTSA proposes specifying a 
plug gauge test because the agency tentatively concludes that the 
additional weight of the plug gauge may make it less susceptible to 
friction than the ball used in the drop-ball test. The plug gauge test 
that NHTSA is proposing, the details of which are contained in 
paragraph S6.12 of the Proposed Regulatory Text, differs somewhat from 
the plug gauge test specified in SAE J1401 in two respects. First, the 
spherical end of the plug gauge must be able to enter the hose or end 
fitting by applying a force no greater than gravity. Second, the plug 
gauge must fall under the force of gravity within 3 seconds. The agency 
welcomes 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 is proposing.
3. Volumetric Expansion
    Both SAE J1401 and FMVSS No. 106 have similar requirements/
procedures; however, SAE J1401 does not specify tests for hoses other 
than \1/8\ or \3/16\ inch. FMVSS No. 106 includes requirements for 
hoses smaller than \1/8\ inch, larger than \1/4\ inch, and also for 
metric nominal hose sizes. NHTSA does not propose to make any changes 
to the volumetric expansion requirements/procedures in FMVSS No. 106.
4. Whip Resistance Test
    The whip resistance requirements/procedures for hydraulic brake 
hose in SAE J1401 and FMVSS No. 106 are similar. Both SAE J1401 and 
FMVSS No. 106 specify that a hydraulic brake hose assembly shall not 
rupture when run continuously on a flexing machine for 35 hours. The 
test procedures differ, however, regarding the level of water pressure 
to be exerted in conducting the whip resistance test. While FMVSS No. 
106 specifies a constant minimum water pressure of 235 psi during the 
test, SAE J1401 specifies a water pressure range of 225 to 250 psi. The 
agency does not propose any changes to Standard No. 106's existing test 
procedures for whip resistance because the existing specifications are 
so close to the upper pressure limit specified in SAE J1401.
5. Tensile Strength
    FMVSS No. 106 specifies that a hose assembly shall have a minimum 
tensile strength of 325 pounds when pulled at a rate of 1 inch per 
minute. SAE J1401 includes this same specification, but also specifies 
an additional tensile strength of 370 pounds when pulled at a faster, 2 
inches per minute, rate. Therefore, SAE J1401's test environment is 
more severe than that specified in FMVSS No. 106. NHTSA proposes that 
the SAE J1401 fast-pull test and 370 pound strength requirement be 
incorporated into FMVSS No. 106. The agency also proposes to update the 
ASTM reference for tension testing machines to the latest version of 
the standard practice.
6. Water Absorption and Pressure Test, Tensile Strength, and Whip 
Resistance
    Both SAE J1401 and FMVSS No. 106 have identical specifications for 
the conditioning of the hose assembly in water for 70 hours, but the 
subsequent test conditions (which are also used for non-water 
conditioned hose) vary, given the aforementioned differences between

[[Page 26388]]

the pressure, tensile strength, and whip resistance requirements in SAE 
J1401 and FMVSS No. 106. NHTSA does not propose any changes to the 
existing water absorption requirements of FMVSS No. 106 but, as noted 
above, NHTSA does 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.
7. Low Temperature Resistance Test
    Both SAE J1401 and FMVSS No. 106 specify identical test procedures 
for bending brake hose around a test cylinder after conditioning at 
minus 40 degrees F. However, SAE J1401 does not include test cylinder 
dimensions for hoses with inside diameters other than \1/8\ inch or \3/
16\ inch, while FMVSS No. 106 includes test cylinder dimensions 
applicable to all sizes of brake hose. NHTSA does not propose any 
changes in Standard No. 106's low temperature resistance requirements/
procedures.
8. Brake Fluid Compatibility, Constriction, and Burst Strength
    FMVSS No. 106 specifies that the hose be conditioned with SAE RM-
66-05 Compatibility Fluid at 200 degrees F for 70 hours, and then 
subjected to constriction and burst strength tests. SAE J1401 specifies 
that the hose be conditioned using SAE RM-66-03 Compatibility Fluid at 
248 +9 -0 degrees F for 70 to 72 hours prior to the constriction and 
burst strength tests. Thus, when compared to the test procedures 
specified in Standard No. 106, the SAE J1401 test is run at a higher 
temperature and uses the older SAE compatibility fluid. Because the RM-
66-05 fluid has superceded the RM-66-03 fluid, NHTSA does not propose 
any change in the type of fluid specified for conditioning the hose. 
NHTSA does propose, however, to increase the conditioning temperature 
in FMVSS No. 106 to 248 degrees F.
9. Ozone Resistance
    The test cylinder dimensional specifications in SAE J1401 and FMVSS 
No. 106 are the same, although the test procedures in FMVSS No. 106 
account for hose that are not long enough to fit all the way around the 
test cylinder, while SAE J1401 provides test procedures for hose that 
exceed the test cylinder circumference and also for hose that collapse 
when subject to bending. SAE J1401 requires a higher concentration of 
ozone of 100 parts per million (ppm) compared to FMVSS No. 106, which 
requires a concentration of 50 ppm.
    Both SAE J1401 and FMVSS No. 106 specify a conditioning temperature 
of 104 degrees F. In addition, both SAE 1401 and FMVSS No. 106 specify 
that the hose be subjected to ozone for at least 70 hours after which 
no visible cracks in the hose may be apparent when examined under 7-
power magnification. Unlike FMVSS No. 106, however, SAE J1401 includes 
an additional dynamic ozone test, in which a cut length of hose is 
mounted in an environmental chamber, exposed to ozone at a 100 ppm 
concentration, and flexed on a specified apparatus through 3 inches of 
stroke at 0.3 Hz for 48 hours. SAE J1401 specifies that no cracking of 
the hose is permissible after 48 hours.
    NHTSA proposes to upgrade FMVSS No. 106's ozone resistance 
requirements to incorporate the 100-ppm ozone concentration in SAE 
J1401. The agency also proposes to incorporate the dynamic ozone test 
in SAE J1401 into Standard No. 106. NHTSA tentatively concludes that 
such an upgrade is appropriate given the well-documented increase in 
ground-layer ozone formation and concentration in U.S. cities that has 
occurred since FMVSS No. 106 was first proposed in 1967. Requiring 
hydraulic brake hose to sustain increased ozone concentrations should 
more accurately reflect the present-day operating environments of brake 
hose and may prevent premature failure of the hose due to ozone 
exposure.
10. End Fitting Corrosion Resistance
    Both SAE J1401 and FMVSS No. 106 specify exposing hydraulic brake 
hose end fittings to salt spray in a chamber for 24 hours. The salt 
spray chamber specified in FMVSS No. 106 is based on specifications 
outlined in ASTM B117-64, while the chamber specifications in SAE J1401 
are based on ASTM B 117 Appendix B. NHTSA tentatively concludes these 
are different versions of the same ASTM Standard Practice B117, which 
has been revised over time. Instead of referencing either ASTM B117-64 
or ASTM B 117 Appendix B, both of which are outdated, NHTSA proposes 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.
    Another difference between the end fitting corrosion resistance 
specifications in SAE J1401 and FMVSS No. 106 pertains to the mounting 
angle of the hose. SAE J1401 specifies that the hose shall be mounted 
at an angle between 15 and 30 degrees from vertical while FMVSS No. 106 
specifies an angle of 30 degrees. Most of the end fitting corrosion 
resistance performance requirements in SAE J1401 and FMVSS No. 106 are 
similar or identical, with SAE J1401 typically providing tolerances on 
all parameters. SAE J1401 excludes brass end fittings from testing 
because apparently SAE deems those end fittings to have adequate 
corrosion resistance. While the two sets of performance requirements 
are very similar, Standard No. 106's requirements are somewhat more 
rigorous and inclusive. Accordingly, with the exception of updating the 
reference to the most recent set of ASTM specifications for salt spray 
chambers, NHTSA proposes no changes to the end fitting corrosion 
resistance requirements/procedures in FMVSS No. 106.
11. High Temperature Impulse Test
    SAE J1401 specifies a hot impulse test in which a hose assembly is 
filled with brake fluid and subjected to 150 cycles of 1600 psi for one 
minute, then zero pressure for one minute, at an elevated temperature 
of 259 degrees F. After this test procedure, the hose assembly is 
cooled and subjected to a burst test with a specified minimum burst 
pressure of 5,000 psi. FMVSS No. 106 does not include a hot impulse 
test. Accordingly, NHTSA proposes incorporating the high temperature 
impulse test from SAE J1401 into FMVSS No. 106.
    The table below summarizes the differences between the hydraulic 
brake hose requirements/procedures of FMVSS No. 106 and SAE J1401 and 
indicates which requirements/procedures NHTSA proposes incorporating 
into the standard.

[[Page 26389]]



 Table 1.--Comparison of Hydraulic Brake Hose Requirements in FMVSS No.
                            106 and SAE J1401
------------------------------------------------------------------------
                                    Existing FMVSS
    Requirement/procedure              No. 106              SAE J1401
------------------------------------------------------------------------
                          Hydraulic Brake Hoses
``x'' Indicates Requirements/Procedures Proposed To Be Included in FMVSS
                                 No. 106
------------------------------------------------------------------------
Pressure Test...............  ...  5,000 psi burst   x   7,000 psi
                                    strength              specified for
                                    specification,        \1/8\ in.
                                    all hoses.            hose, same for
                                                          \3/16\ in.
                                                          hose.
Constriction................   1   Similar           1   Similar, does
                                    dimensional           not specify \1/
                                    specifications.       4\ in. hose
                                                          size.
Volumetric Expansion........   x   Same...........  ...  Same.
Whip Test...................   x   Same...........  ...  Same.
Tensile Strength............  ...  Slow pull rate    x   Includes slow
                                    test.                 plus fast pull
                                                          rate tests.
Water Absorption and           x   Similar, note    ...  Similar.
 Pressure Test.                     differences in
                                    pressure test.
Water Absorption and Tensile  ...  Similar, except   x   Similar, but
 Strength.                          fast pull rate        includes fast
                                    test not              pull rate.
                                    included.
Water Absorption and Whip      x   Similar........  ...  Similar.
 Resistance.
Low Temperature Resistance     x   Same...........  ...  Same, but does
 Test.                                                    not cover all
                                                          hose sizes.
Brake Fluid Compatibility,    ...  Lower             x   Higher
 Constriction, and Burst            conditioning          conditioning
 Strength.                          temperature.          temperature,
                                                          older version
                                                          of test fluid
                                                          (use RM-66-05
                                                          fluid).
Ozone Resistance............  ...  Similar, 50 ppm   x   Similar, 100
                                    ozone                 ppm ozone
                                    concentration.        concentration.
Dynamic Ozone Test..........  ...  Not included...   x   Flex hose in
                                                          ozone chamber
                                                          for 48 hours.
End Fitting Corrosion          x   Similar, 30      ...  Similar, 15-30
 Resistance.                        degree                degree
                                    mounting angle.       mounting
                                                          angle, brass
                                                          material
                                                          exempt.
High Temperature Impulse      ...  Not included...   x   Pressure
 Test.                                                    cycling at
                                                          elevated
                                                          temperature
                                                          followed by
                                                          burst test;
                                                          does not cover
                                                          \1/4\ in.
                                                          brake hose.
------------------------------------------------------------------------
Note 1: Use existing FMVSS No. 106 constriction requirement, propose
  that J1401 plug gauge test method be adopted in Test Procedure 106,
  add drop time.

B. Air Brake Hoses

    NHTSA's performance requirements and test procedures relating to 
air brake hose are located in paragraph S7, Requirements--Air brake 
hose, brake hose assemblies, and brake hose end fittings, and paragraph 
S8, Test procedures--Air brake hose, brake hose assemblies, and brake 
hose end fittings, of FMVSS No. 106. The corresponding SAE 
requirements/procedures are contained in SAE Surface Vehicle 
Recommended Practice J1402, Automotive Air Brake Hose and Hose 
Assemblies, Rev. June 1985 (SAE J1402).
    NHTSA proposes to update FMVSS No. 106 to include performance 
requirements from SAE Recommended Practice J1402 that are not presently 
contained in the standard. The agency notes that, as was the case for 
hydraulic and vacuum brake hoses, air brake hose requirements as 
originally incorporated in Standard 106 in November of 1973 (38 FR 
31302) were based on the substantive requirements in SAE J1402.
    NHTSA tentatively concludes that virtually all air-braked vehicles 
are currently equipped with air brake hoses that meet SAE J1402 because 
many of these vehicles are used in commercial operations, and therefore 
are subject to the current FMCSA regulations requiring use of air brake 
hoses that comply with SAE J1402. While some vehicles equipped with air 
brake systems may not be operated as commercial vehicles, such as 
heavy-duty motor homes, the agency tentatively concludes that such 
vehicle populations are small in comparison to the number of straight 
trucks, tractors, and air-braked buses. NHTSA tentatively concludes 
that it is likely that the air brake hose, assemblies, and fittings on 
these non-commercial vehicles are already compliant with SAE 1402's 
specifications, however, because SAE 1402-compliant air brake hose 
products are the most widely available in the United States. 
Nevertheless, the agency welcomes comments on whether air brake hoses 
currently in use on commercial and non-commercial vehicles are designed 
to meet the specifications in SAE J1402.
    A detailed discussion of the differences between the air brake 
hose, assemblies, and end fitting performance requirements and test 
procedures in SAE J1402 and FMVSS No. 106 follows, along with the 
agency's proposed resolution of those differences.
1. Dimensional Requirements
    FMVSS No. 106 requires that hose constructed of synthetic or 
natural elastomeric rubber and intended for use with reusable end 
fittings must conform to the dimensional requirements listed in Table 
III of paragraph S7.1, Construction. Standardized dimensional 
requirements for hose with reusable end fittings guard against the 
possibility that replacement hose will not properly fit the end 
fittings. Table III lists required inside diameter (ID) and outside 
diameter (OD) dimensions for Type AI and Type AII air brake hose 
manufactured in fractional-inch sizes.
    SAE J1402 includes the same dimensional requirements for AI and AII 
hose, but also includes dimensions for Type ``A'' hose. Type A air 
brake hose are primarily used with permanently attached end fittings, 
unlike Types AI and AII air brake hose, which are used with reusable 
end fittings. Some Type A hose, specifically \3/8\ inch, \7/16\ inch, 
and \1/2\ inch ``Special'' hose, may also be fitted with reusable end 
fittings. SAE J1402's dimensional requirements apply to all Type A 
hose, regardless of whether they are fitted with permanent or reusable 
end fittings. With respect to the Type A \3/8\-inch and Type A \1/2\-
inch ``Special'' hose, the agency notes that there are already 
corresponding dimensions included in Table III of FMVSS No. 106 with 
identical dimensions for both Type AI and Type AII hose. Under FMVSS 
No. 106, a \1/2\-Special or \3/8\ brake hose can be labeled to include 
the ``A,'' ``AI,'' and/or ``AII'' designations, or any combination 
thereof (e.g., ``AI-AII''), as the hose manufacturer deems appropriate.
    Although the petitioners did not specifically request the 
incorporation of SAE J1402's dimensional requirements for Type A air 
brake hose into FMVSS No. 106, the agency notes that it once considered 
whether to do so. In a June 28, 1974, final rule (39 FR 24012, Docket 
No. 1-5; Notice 11), the agency

[[Page 26390]]

decided against including dimensional requirements for Type A air hose 
in FMVSS No. 106. The agency stated that the primary purpose of the 
dimensional requirements was to prevent mismatch between reusable end 
fittings and replacement brake hose. At that time, hose used with 
permanent end fittings were generally assembled by high volume 
manufacturers rather than repair operations in the field. The agency 
did not believe that there was a safety need to provide dimensional 
requirements for hose assemblies manufactured in such a manner. 
Accordingly, NHTSA found that including dimensional requirements for 
air brake hose used with permanent end fittings would amount to ``a 
design restriction without corresponding safety benefit.''
    NHTSA no longer believes that only high-volume brake hose 
manufacturers are assembling air brake hoses with permanently attached 
fittings. A review of brake hose manufacturers that are registered with 
NHTSA indicates that many truck repair facilities are registered, and 
the agency tentatively concludes that many of these facilities may be 
capable of assembling brake hoses with permanently attached end 
fittings as replacement parts. NHTSA does not know the extent to which 
air brake hose that meets SAE J1402 dimensional requirements for Type A 
hose is used in such replacement assemblies, but tentatively concludes 
it is likely that most, if not all, such hose already comply with SAE 
J1402's dimensional requirements because Sec.  393.45 requires that 
hoses used on commercial motor vehicles comply with SAE 1402.
    NHTSA is not proposing to incorporate into FMVSS No. 106 the 
dimensional requirements for rubber hose used with permanently attached 
end fittings found in Table A of SAE J1402. In the case of \7/16\-inch 
hose, which is not currently listed in Table III of FMVSS No. 106, 
NHTSA proposes to add this hose size to the dimensional tables for Type 
I and Type II hose, which would have the effect that as indicated in 
SAE J1402, \7/16\-inch hose could be used with either permanent or 
reusable fittings, as is the case for \3/8\-inch and \1/2\-inch Special 
hose as currently included in Table III of FMVSS No. 106. Hose 
manufacturers would then be able to label \7/16\-inch hose with a 
designation of ``A,'' ``AI,'' and/or ``AII,'' as they deem appropriate. 
NHTSA welcomes public comments on this proposal, and also requests any 
dimensional and descriptive information for other sizes of air brake 
hose that manufacturers may be producing that is not covered under SAE 
J1402. NHTSA also welcomes public comments on whether FMVSS No. 106 
should include dimensional requirements for metric sized hose used with 
reusable end fittings as Standard No. 106 currently does not provide 
requirements for such hose. Note that Standard No. 106 does include 
references to metric sizes of air brake hose that presumably is used 
with permanently-attached end fittings.
2. Construction and Labeling
    Paragraphs S7.1, Construction, and S7.2, Labeling, both contain 
references to air brake hoses constructed of synthetic or natural 
elastomeric rubber to differentiate those hose types from air brake 
tubing constructed from nylon (plastic), with both rubber hose and 
nylon tubing currently regulated as air brake hoses under paragraphs S7 
and S8. The designation for synthetic or natural elastomeric rubber 
hoses was added to FMVSS No. 106 in a 1991 final rule (56 FR 7589) so 
that the dimensions for hoses used with reusable fittings in Table III 
would not apply to plastic tubing. NHTSA proposes, as discussed in 
another section below, 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 rubber hoses. 
Therefore, NHTSA proposes that any references to synthetic or natural 
elastomeric rubber be deleted from S7 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 this notice also removes references 
to ``outside diameter (OD)'' from S7 and S8 of FMVSS No. 106 since OD 
measurements are generally only applicable to tubing, which NHTSA 
proposes to address in the new section for plastic tubing.
    NHTSA also proposes to specify in S7.2.1(e) of FMVSS No. 106 the 
labeling scheme that is to be used for air brake hose that meet 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 inserting this 
language in FMVSS No. 106 would serve to minimize confusion on this 
issue. The proposed text also states 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 for their hoses to be used, 
and would not require them to label hoses for multiple end fitting 
designations unless they so desire.
3. Manufacturer Identification
    While the labeling requirements in FMVSS No. 106 and SAE J1402 
differ somewhat, both can be accommodated on a single brake hose. SAE 
J1402 requires each manufacturer to register the identification of its 
yarn scheme in accordance with SAE J1401, Appendix B and to label each 
hose with its manufacturer's identification number. Similarly, FMVSS 
No. 106 requires that hose manufacturers register with NHTSA and 
imprint their name or symbol on subject hoses and/or fittings. The 
agency does not propose to change FMVSS No. 106's manufacturer 
identification or labeling requirements.
4. Constriction
    The constriction requirements relating to air brake hose are found 
in paragraph S7.3.1 of FMVSS No. 106. Standard No. 106 requires that 
every inside diameter of any section of each air brake hose assembly 
shall be not less than 66 percent of the nominal inside diameter of the 
hose, except for those portions of end fittings that do not contain 
hose. SAE J1402 also requires air brake hose assembly to meet a 66 
percent of nominal inside diameter requirement but, unlike FMVSS No. 
106, it does not exclude the portions of end fittings not containing 
hose. NHTSA proposes to eliminate the exclusion in S7.3.1 for those 
portions of end fittings which do not contain hose, as the agency does 
not believe that end fittings for air brake hose include restrictions 
designed into the fittings, nor are there complex shapes for end 
fittings as found with some hydraulic brake hoses. NHTSA welcomes 
public comments on this proposal. NHTSA also proposes that the same 
test method proposed for testing hydraulic brake hoses for constriction 
be specified for testing air brake hoses. In addition, noting that the 
title of paragraph S7.3.1 contains a typographical error, NHTSA 
proposes to change the title of S7.3.1 from ``Construction'' to 
``Constriction.''
5. High Temperature Resistance
    FMVSS No. 106 includes a test in which the hose is bent around a 
test cylinder, conditioned at 212 degrees F for 70 hours, then cooled 
and straightened. No charring, disintegration, or cracks are permitted. 
The high temperature test specifications for air brake hose contained 
in SAE J1402 are similar, but not identical, to those in FMVSS. First, 
the radii of the test cylinders specified for each hose size are 
significantly smaller in SAE J1402 than in FMVSS No. 106. Second, 
unlike FMVSS No. 106, SAE J1402 does

[[Page 26391]]

not include test cylinder radii specifications for \1/8\-inch ID hose. 
Third, SAE J1402 does not provide specifications for metric sized hose. 
Instead, the SAE specification provides only metric conversions for 
inch sizes of hose. Fourth, unlike FMVSS No. 106, SAE J1402 excludes 
hose with fabric covering from external inspection for cracks, stating 
that visual inspection is not practical.
    NHTSA proposes 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 proposes 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 proposes 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 disagrees that external inspection of such hose is impractical 
and, therefore, does not propose to incorporate SAE J1402's exclusion.
6. Low Temperature Resistance
    FMVSS No. 106 specifies that the hose and test cylinder be 
conditioned at minus 40 degrees F for 70 hours, followed by bending the 
hose 180 degrees around the test cylinder. No cracks may be visible on 
the outside cover of the hose after performing this test. The test 
procedure in SAE J1402 is similar, including the radii of the test 
cylinders, except that it does not specify test cylinder radii for \1/
8\ inch or 3mm hose. SAE J1402 also prohibits cracks on the inside of 
the hose and, in this respect, the SAE test is more severe than the one 
specified by FMVSS No. 106. Unlike FMVSS No. 106, however, SAE J1402 
excludes the exterior surface of hoses covered with fabric from 
external inspection.
    The agency indicated in a February 26, 1974 final rule (39 FR 7425, 
Docket No. 1-5, Notice 10) amending FMVSS No. 106 that it would 
consider specifying inspection of the inner layer of an air brake hose 
subjected to the low-temperature resistance test at a future date. In 
addition, the agency notes that the test procedure for Standard No. 
106, TP-106, specifies that the same test procedure be used for air 
brake hose as for hydraulic brake hose, using the test cylinders sized 
for air brake hose, and does include internal inspection of both types 
of hoses. NHTSA is now proposing that the internal surface inspection 
of air brake hose, as specified in SAE J1402, be incorporated into 
FMVSS No. 106. The agency does not propose, however, to incorporate SAE 
J1402's exclusion of fabric-covered air brake hose from external 
inspection.
7. Oil Resistance
    Paragraphs S7.3.4, Oil resistance, and S8.3, Oil resistance test, 
of FMVSS No. 106 specify that specimens prepared from the inner tube 
and outer cover of the subject brake hose, when immersed in American 
Society of Testing and Materials (ASTM) No. 3 oil for 70 hours at 212 
degrees F, shall not increase in volume by more than 100 percent. SAE 
J1402 contains an identical test procedure. As indicated in ASTM D147-
98e1, Standard Test Method for Rubber Property--Effect of Liquids, ASTM 
No. 3 oil is no longer commercially available and has been superseded 
by IRM 903 oil. Accordingly, NHTSA proposes that all references in 
S7.3.4 and S8.3 to ASTM No. 3 oil be changed to specify IRM 903 oil. 
The agency does not propose any additional changes to FMVSS No. 106's 
oil resistance requirements/specifications.
8. Ozone Resistance
    FMVSS No. 106's ozone resistance requirements/specifications for 
air brake hose are the same as those specified for hydraulic brake 
hose. Standard No. 106 specifies that air brake hose be conditioned in 
an ozone chamber for 70 hours at 104 degrees F while the hose is 
secured around a test cylinder. Because the test procedure for air 
brake hose, S8.4 (Ozone resistance test), specifies that the same test 
procedure for a hydraulic brake hose ozone resistance test be utilized, 
and because NHTSA is proposing that the ozone concentration for 
hydraulic brake hose be changed from 50 ppm to 100 ppm, NHTSA proposes 
to specify the higher ozone concentration (100 ppm) for air brake hose 
as well. The agency tentatively concludes it is appropriate to specify 
the same concentration of ozone for testing all types of brake hoses 
and welcomes public comments on this issue.
9. Length Change
    Paragraph S7.3.6, Length change, of FMVSS No. 106 requires that air 
brake hose, when subjected to 200 psi of air pressure, shall not 
contract more than 7 percent nor elongate more than 5 percent over the 
length of the hose. The associated test procedure, found in paragraph 
S8.5, Length change test, specifies that the initial length of the hose 
be measured at a pressure of 10 psi. Coiled nylon tube may 
alternatively comply with requirements in FMCSR 393.45 (which 
references J844 for nylon air brake tubing). SAE J1402's length change 
requirements/procedures are identical to those in FMVSS No. 106. 
Considering that FMCSA and NHTSA are proposing to consolidate all 
federal brake hose requirements/procedures into FMVSS No. 106 and 
because NHTSA is proposing specific requirements/procedures for plastic 
air brake tubing, the agency proposes to delete the option for coiled 
nylon tube to comply with FMCSR 393.45 from Standard No. 106. Aside 
from deleting this reference, the agency does not propose any 
additional changes to the length change requirements/procedures in 
FMVSS No. 106.
10. Adhesion
    FMVSS No. 106 requires a minimum separation strength of 8 pounds 
per linear inch for each layer in an air brake hose, except for hose 
reinforced by wire. SAE J1402 has a similar requirement for non-wire 
reinforced hose, and a separate test procedure for wire reinforced 
hose, in which a steel ball is placed inside the hose sample, one end 
is capped and the other connected to a vacuum source, and the hose is 
bent 180 degrees around a test cylinder in one direction and then the 
opposite direction. While still under vacuum, the hose is straightened 
and the steel ball must be able to roll from one end of the hose to the 
other. NHTSA proposes 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.
    The table of steel ball sizes for this test procedure in SAE J1402 
indicates that for all but the \13/32\-inch hose sizes, the ball 
diameter is equal to 75 percent of the nominal hose ID. For the \13/
32\-inch hose size, the specified ball diameter is 73 percent of the 
nominal hose ID. It appears that the reason for this one difference is 
that the ball sizes in the table are standard size steel balls measured 
in 64ths of an inch, thus 75 percent of \13/32\-inch is slightly larger 
than \19/64\-inch and 73 percent of \13/32\ equals \19/64\-inch. The 
table in SAE J1402 also does not provide corresponding steel ball sizes 
for metric sized hose. Accordingly, to incorporate SAE J1402's 
specifications into FMVSS No. 106, NHTSA proposes that rather than 
specifying steel ball diameters for each hose size, the steel ball 
should be

[[Page 26392]]

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. NHTSA welcomes public comments on this issue.
    The agency notes that it is proposing 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 proposes to 
specify the use of a steel ball to test air brake hose for adhesion. 
Finally, the agency proposes 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.
11. Air Pressure (Leakage)
    FMVSS No. 106 specifies that an air brake hose assembly be 
subjected to a 200-psi pressure test. Once the target pressure is 
reached, the hose is sealed and the pressure drop over a five-minute 
period may not exceed 5 psi.
    SAE J1402 has two test procedures to evaluate the leakage from air 
hose assemblies. In the first test, two hose assemblies are tested as 
follows. One hose assembly is subjected to the high temperature 
resistance test described above, and is then subjected to a 300-psi 
pressure test using air or nitrogen, under water, with no visible 
leakage for 30 seconds. The second hose assembly is subjected to the 
low temperature resistance test described above, and is then subjected 
to a 300-psi pressure test using air or nitrogen, under water, with no 
visible leakage for 30 seconds.
    In the second test, a flexure test is performed as follows. A test 
hose assembly is prepared to the length shown in Figure 2 of that 
standard. The hose is preconditioned by exposure to a salt spray for 24 
hours with the ends sealed, followed by high-temperature aging at 212 
degrees F for 70 hours with the ends open and, within 168 hours of 
completion of the preconditioning, the hose is subjected to the flex 
test. The hose is mounted on the flex test fixture as described in 
Figure 2, with the hose being subjected to a 6-inch stroke while the 
air pressure in the hose is cycled between 0 psi for one minute and 150 
psi for one minute. With the flexure machine stroking at 100 cycles per 
minute, the hose is subjected to 1 million stroke cycles. Upon 
completion of the 1 million cycles, the hose must be capable of 
maintaining 150-psi +/-10 psi when air is supplied through a \1/16\-
inch diameter orifice.
    The SAE J1402 specifications for hose leakage are more severe than 
those presently in FMVSS No. 106, and NHTSA proposes incorporating them 
into Standard 106, with the following modifications. SAE J1402 
specifies that upon completion of the high-temperature aging test, the 
hose assembly must be flex tested within 168 hours. NHTSA tentatively 
concludes there could be variability introduced in the test results if, 
for example, the hose was immediately flex tested after the high-
temperature test, or if the hose were allowed to cool before being flex 
tested. Therefore, NHTSA proposes that upon completion of the high-
temperature aging test, the hose assembly be cooled at room temperature 
for two hours, and the flex test then be initiated within 166 hours 
from that time.
    NHTSA also proposes to modify SAE J1402's testing procedures by 
specifying the thickness of the orifice during the final leak check 
because 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. 
This would be critical if a small amount of hose leakage is present 
during the final leakage test. NHTSA proposes specifying an orifice 
thickness of 0.032 inches (\1/32\-inch), which is the same thickness 
specified for the orifice in FMVSS No. 121 S5.3.5, Control signal 
pressure differential for converter dollies and trailers designed to 
tow another vehicle equipped with air brakes. NHTSA tentatively 
concludes 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. NHTSA welcomes 
comments on this proposal.
    With respect to the amount of leakage that is permitted after the 
flex test is conducted, SAE J1402 is not absolutely specific. SAE J1402 
defines failure as the hose's inability to be repressurized to 150-psi 
+/-10 psi, supplied through the 0.062-inch orifice, within 2 minutes. 
SAE J1402 specifies that the supply air pressure to the orifice is 150 
psi +/-10 psi. Accordingly, a hose supplied with up to 160-psi supply 
air pressure and resulting in 140-psi pressure in the hose assembly 
could conceivably be construed as passing the test. On the other hand, 
the specifications could be construed as permitting no leakage, that 
the pressure in the hose assembly must equal the supply pressure, 
within a range of 140 psi to 160 psi. If that were the case, however, 
there would be no need for an orifice to be included in the test 
apparatus.
    NHTSA proposes to specify a supply pressure of 150 psi and to 
further specify that the pressure in the hose assembly must reach 140 
psi within 2 minutes. NHTSA notes that this is consistent with the 
existing requirements in FMVSS No. 106, S7.3.8 Air pressure, which 
permits a small amount of leakage in an air brake hose assembly, albeit 
without prior conditioning. NHTSA welcomes comments on these proposed 
leakage specifications.
12. Burst Strength
    FMVSS No. 106 requires that an air brake hose assembly shall not 
rupture when subjected to a hydrostatic pressure of 800 psi. SAE J1402 
specifies that a hose assembly be first subjected to a 24-hour salt 
spray test, with no resulting corrosion other than as permitted by that 
standard, and then shall not burst or separate from an end fitting at a 
hydrostatic pressure of 900 psi. SAE J1402's burst strength 
specifications/requirements are more severe than those in FMVSS No. 
106. NHTSA proposes to incorporate SAE J1402's burst strength 
specifications/requirements into Standard No. 106.
13. Tensile Strength
    FMVSS No. 106 specifies that a hose assembly for use between either 
the frame and the axle or between a towed and towing vehicle meet a 
longitudinal pull test, at a 1 inch per minute force application rate, 
and not separate from its end fittings at the following force levels: 
250 pounds for \1/4\ inch or less, or 6mm or less, nominal ID; 325 
pounds for more than \1/4\ inch or 6mm nominal ID. A hose assembly used 
in any other application must withstand force levels of: 50 pounds for 
\1/4\ in or less (or 6 mm or less) nominal ID; 150 pounds for \3/8\ 
inch, \1/2\ inch, or 10 mm to 12 mm, nominal ID; and 325 pounds if the 
hose assembly is larger than \1/2\ inch (or 12 mm) nominal ID. A coiled 
nylon tube assembly can either meet these requirements or, 
alternatively, can meet the requirements in FMCSR Sec.  393.45.
    The distinction between a brake hose used between a frame and axle 
or between a towed and towing unit, and hose used for other purposes, 
was added to Standard No. 106 on February 26, 1974 (39 FR 7425), in 
response to petitions for reconsideration of certain brake hose 
requirements. This distinction was introduced in response to the 
inclusion of plastic tubing as an air brake hose, and permitted lower 
tensile strength requirements for plastic tubing used in chassis 
applications.

[[Page 26393]]

Because the agency is now proposing separate requirements for plastic 
tubing in a new section of FMVSS No. 106, NHTSA proposes to delete the 
lower tensile strength limits for hose that are used for purposes other 
than connections between a frame and axle or between a towed and towing 
unit.
    The agency proposes that all rubber brake hose meet the 
requirements for hose that is used between a frame and axle or between 
a towed and towing unit. NHTSA tentatively concludes 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. An 
example of a chassis plumbing use for rubber hose is to connect an air 
dryer to the wet tank, although here again many vehicles use plastic 
tubing in this application. NHTSA tentatively concludes that these 
rubber hoses are of sufficient diameter to have the mechanical strength 
to meet the higher, frame-to-axle tensile strength requirements. These 
requirements are similar to the ones originally proposed for FMVSS No. 
106 prior to the accommodation of plastic tubing strength requirements. 
In addition, these tensile strength requirements are currently 
specified in SAE J1402, which does not distinguish based on the 
application of the hose and includes the higher force specification. 
SAE J1402 does not specify a stand-alone tensile strength test, but 
does specify a water absorption test followed by a tensile strength 
test, described below. NHTSA welcomes comments on the proposed tensile 
strength requirements and information on any alternate tensile strength 
requirements that might be appropriate for rubber hose.
    NHTSA also proposes to delete the reference to FMCSR Sec.  393.45 
in paragraph S7.3.10 because NHTSA is proposing to incorporate into 
FMVSS No. 106 many of the SAE requirements referenced in Sec.  393.45 
for plastic air brake tubing.
14. Water Absorption and Tensile Strength
    FMVSS No. 106 specifies that a hose assembly be immersed in 
distilled water for 70 hours at room temperature and, within 30 minutes 
of being removed from the water, be subjected to the tensile strength 
test and requirements described above. A coiled nylon tube assembly can 
either meet these specifications/requirements or, alternatively, the 
requirements in FMCSR Sec.  393.45.
    SAE J1402 specifies bending a hose assembly around a test cylinder 
and, with its ends capped, immersed in tap water at room temperature 
for 168 hours. Following this, the hose assembly is subjected to a 
tensile pull test, with the following force levels specified to be 
achieved without separation or rupture: 250 pounds for hose of \1/4\ 
inch, or 6.4 mm, or less, nominal ID; 325 pounds for hose larger than 
\1/4\ inch or 6.4 mm. Thus, the tensile strength required in SAE J1402 
is similar to that in FMVSS No. 106 for a hose used between a frame and 
axle, or between a towed and towing vehicle. SAE J1402 does not, 
however, include lower tensile strength values for hoses that are used 
between components that do not experience substantial relative motion 
and it also does not address plastic tubing.
    Although the SAE J1402 test specifies a longer water conditioning 
period than FMVSS No. 106, which would make those specifications more 
severe, FMVSS No. 106 specifies that the ends of the hose assembly be 
left open thereby exposing the inside of the hose to water. SAE J1402 
also specifies that tap water rather than distilled water (as specified 
in FMVSS No. 106) be used in this test, which could introduce 
variability in test results depending on compounds that are in the tap 
water at any particular location. On balance, it would be difficult to 
state which test condition is more severe, but NHTSA proposes that the 
current requirements in paragraph S7.3.11, Water absorption and tensile 
strength, be retained, except as modified by proposed changes to the 
stand-alone tensile strength requirements discussed above. NHTSA also 
proposes to delete the reference to FMCSR Sec.  393.45 in S7.3.11.
15. Zinc Chloride Resistance
    Paragraph S7.3.12, Zinc chloride resistance, of FMVSS No. 106 
requires that a hose assembly be immersed in a 50 percent zinc chloride 
aqueous solution for 200 hours, with no visible cracks permitted when 
viewed with 7 power magnification. SAE J1402 does not include a similar 
requirement. NHTSA does not propose any changes in Standard No. 106's 
zinc chloride resistance requirements.
16. End Fitting Corrosion Resistance
    FMVSS No. 106 requires that air brake hose end fittings meet the 
same requirements as those specified for hydraulic brake hose end 
fittings. As is the case for hydraulic brake hoses per SAE J1401, SAE 
J1402 references the ASTM B117 Method of Salt Spray (Fog) Testing while 
FMVSS No. 106 references ASTM B117-64. Unlike SAE J1401, SAE J1402 does 
not exclude brass end fittings from this requirement. While SAE J1402 
does not specify the attitude of the brake hose assembly in the 
chamber, FMVSS No. 106 specifies a 30-degree from vertical angle. 
Because FMVSS No. 106's end fitting corrosion resistance requirements 
appear to be more rigorous, NHTSA does not propose any changes to these 
requirements.
17. Minimum Bend Radius
    SAE J1402 specifies minimum bend radius requirements for hose as 
installed on a vehicle. NHTSA tentatively concludes it would not be 
appropriate to add these requirements to FMVSS No. 106 because FMVSS 
No. 106 regulates the properties of brake hoses as stand-alone motor 
vehicle equipment rather than use requirements.
    The table below summarizes the differences between the air brake 
hose requirements/procedures of FMVSS No. 106 and SAE J1402 and 
indicates which requirements/procedures NHTSA proposes incorporating 
into the standard.

 Table 2.--Comparison of Air Brake Hose Requirements/Procedures in FMVSS
                          No. 106 and SAE J1402
------------------------------------------------------------------------
                                    Existing FMVSS
    Requirement/procedure              No. 106              SAE J1402
------------------------------------------------------------------------
                             Air Brake Hoses
``x'' Indicates Requirements/Procedures Proposed To Be Included in FMVSS
                                 No. 106
------------------------------------------------------------------------
Dimensional Specifications..   x   Similar, does    ...  Similar, but
                                    not include           includes Type
                                    Type A hose.          A hose.
Constriction................   x   Similar,         ...  Similar but
                                    includes end          does not
                                    fittings.             include end
                                                          fittings.
High Temperature Resistance.  ...  Similar, but      x   Similar, but
                                    larger test           smaller test
                                    cylinder radii.       cylinder
                                                          radii.

[[Page 26394]]

 
Low Temperature Resistance..   1   Similar,          1   Similar,
                                    excludes              requires
                                    interior of           internal
                                    hose from             inspection,
                                    inspection.           excludes
                                                          fabric covered
                                                          hose exterior
                                                          inspection.
Oil Resistance..............   x   Same...........  ...  Same.
Length Change...............   x   Same; coiled     ...  Same.
                                    nylon can meet
                                    FMCSR Sec.
                                    393.45.
Adhesion....................  ...  Same except for   x   Same but
                                    wire                  includes
                                    reinforced            specific test
                                    hose.                 for wire
                                                          reinforced
                                                          hose.
Air Pressure (Leakage)......  ...  200 psi leak      x   More test
                                    test.                 specifications
                                                          including
                                                          dynamic flex
                                                          test.
Burst Strength..............  ...  800 psi           x   Salt spray test
                                    hydrostatic           followed by
                                    test.                 900 psi
                                                          hydrostatic
                                                          test.
Tensile Strength............   x   Specifies        ...  No
                                    longitudinal          corresponding,
                                    pull test.            stand-alone
                                                          test.
                                                          Specifications
                                                          are in Water
                                                          Absorption
                                                          test.
Water Absorption and Tensile   x   70 hour water    ...  168 hour water
 Strength.                          immersion             immersion
                                    followed by           followed by
                                    pull test;            pull test.
                                    coiled.
Tensile Strength............  ...  Nylon can meet   ...  Followed by
                                    FMCSR 393.45.         pull test.
Zinc Chloride Resistance....   x   200 hour         ...  No
                                    immersion in          corresponding
                                    zinc chloride.        test.
End Fitting Corrosion          x   Similar,         ...  Similar, does
 Resistance.                        specifies             not specify
                                    angle of hose         angle of hose
                                    in test               in test
                                    chamber.              chamber.
Ozone Test..................  ...  No ozone test..   2   Hose bent
                                                          around test
                                                          cylinder
                                                          exposed to 50
                                                          ppm ozone for
                                                          70 hours.
Minimum Bend Radius.........  ...  None...........   3   Specifies
                                                          minimum bend
                                                          radii for hose
                                                          as installed
                                                          on a vehicle.
------------------------------------------------------------------------
Note 1: for low temperature resistance, use the most severe requirements
  from each standard.
Note 2: propose J1402 test, except with 100-ppm ozone concentration.
Note 3: would not be appropriate for FMVSS No. 106.

C. Vacuum Brake Hoses

    NHTSA's performance requirements and test procedures relating to 
vacuum brake hoses are located in paragraph S9., Requirements--Vacuum 
brake hose, brake hose assemblies, and brake hose end fittings, and 
paragraph S10., Test procedures--Vacuum brake hose, brake hose 
assemblies, and brake hose end fittings, of FMVSS No. 106. The 
corresponding SAE requirements are contained in SAE Highway Vehicle 
Standard J1403, Vacuum Brake Hose, Rev. July 1989.
    When requirements for vacuum brake hoses were originally added to 
FMVSS No. 106 in November of 1973 (38 FR 31302), the substantive 
requirements of SAE J1403 were adopted. NHTSA proposes to update FMVSS 
No. 106 to include performance requirements from the most recent 
version of SAE J1403 that are not presently contained in the standard.
    Again, as with hydraulic brake hoses, the agency tentatively 
concludes that many light vehicle manufacturers already voluntarily 
equip their vehicles with vacuum hoses that meet the current version of 
SAE J1403. Accordingly, NHTSA proposes applying the SAE specifications 
to all types of vacuum hoses and not just those used on commercial 
vehicles. The proposed amendments to FMVSS No. 106 represent 
incrementally more severe performance requirements that the industry 
has adopted over the past 20 years.
    The petitioners requested that the requirements of SAE J1403 be 
added to FMVSS No. 106 to upgrade the performance requirements for 
vacuum brake hose. The use of vacuum brake hose in automotive 
applications is generally for the vacuum hose connecting the power 
brake booster to the engine manifold, and although there may be other 
applications for vacuum brake hose, the agency tentatively concludes 
that vacuum-operated braking systems are no longer being used in the 
U.S. Although the use of this type of brake hose may be far more 
limited than it was 40 or 50 years ago, NHTSA tentatively concludes 
that upgrading the requirements for vacuum brake hose is still 
warranted given that use of such hose is still widespread.
    A detailed discussion of the differences between the vacuum brake 
hose performance requirements and test procedures in SAE J1403 and 
FMVSS No. 106 follows, along with the agency's proposed resolution of 
those differences.
1. Constriction
    Paragraph S9.2.1, Constriction, of FMVSS No. 106 requires the 
inside diameter of a heavy duty vacuum hose assembly to be at least 75 
percent of the hose's nominal inside diameter. The inside diameter of a 
light duty vacuum hose assembly is required, by S9.2.1, to be at least 
70 percent of the hose's nominal inside diameter. FMVSS No. 106 
excludes from these performance requirements those portions of the 
hose's end fittings that do not contain hose. Constriction testing, as 
outlined in Testing Procedure 106-08 (TP-106-08), is performed using 
plug gauges with diameters as specified in TP-106-08.
    SAE J1403 does not contain a corresponding set of constriction test 
requirements/procedures. Accordingly, NHTSA does not propose any 
changes to Standard No. 106's constriction requirements/procedures for 
vacuum brake hose. NHTSA does seek public comments, however, on whether 
to continue to exclude those portions of end fittings that do not 
contain hose from the standard's constriction requirements.
2. High Temperature Resistance
    Paragraph S9.2.2, High temperature resistance, of FMVSS No. 106 
specifies bending a length of hose around a cylinder of specified 
diameter and exposing it to air at a temperature of 212 degrees F for 
70 hours. After conditioning the hose in this manner, Standard No. 106 
specifies that the hose be straightened and cut longitudinally and 
visually inspected. No visible cracking, charring, or disintegration on 
the exterior or interior of the hose is permitted.

[[Page 26395]]

    SAE J1403 has a different test procedure in which a straight length 
of hose is subjected to a vacuum and conditioned at 257 degrees F for 
96 hours. After temperature conditioning, the hose is cooled and bent 
around a test cylinder, then visibly inspected for degradation. The 
hose is then subjected to a proof pressure test of 175 psi for one 
minute. Required performance measures include: not more than 10 percent 
collapse of the outside diameter (OD) for heavy-wall hose and not more 
than 15 percent collapse of the OD for light-wall hose after the hot 
aging test; no visible internal or external embrittlement or 
degradation; and no leakage during the high-pressure test.
    While FMVSS No. 106 specifies test cylinder radii for given sizes 
of hose (Table V), SAE J1403 simply specifies a test cylinder that is 
five times the OD of the hose. These test cylinder dimensions cannot be 
compared based on information in the standards because FMVSS No. 106 
does not indicate the OD of the hose.
    Nevertheless, the high temperature resistance requirements in SAE 
J1403 appear to be more rigorous than those in FMVSS No. 106 given that 
standard's post-test dimensional and burst test specifications. 
Accordingly, NHTSA proposes to incorporate SAE J1403's high temperature 
resistance requirements/specifications for vacuum brake hose into FMVSS 
No. 106.
3. Low Temperature Resistance
    Paragraph S9.2.3, Low temperature resistance, of FMVSS No. 106 
specifies conditioning vacuum brake hose, in a straight configuration, 
at minus 40 degrees F for 70 hours and then, while still cold, bending 
the hose 180 degrees around a test cylinder with a radius specified in 
Table V. After performing this test, S9.2.3 specifies visual inspection 
of the hose. No visible cracks on the hose are permitted. SAE J1403 has 
similar provisions, except that after the cold bending test is 
performed, SAE J1403 specifies subjecting the hose to a 175-psi 
pressure test at room temperature with no leakage permitted. SAE 
J1403's low temperature resistance requirements are more rigorous due 
to the addition of this pressure test. Accordingly, NHTSA proposes to 
incorporate SAE J1403's pressure test procedure into FMVSS No. 106.
4. Ozone Resistance
    Paragraph S9.2.4, Ozone resistance, of FMVSS No. 106 specifies 
subjecting vacuum brake hose to an ozone concentration of 50 ppm for 70 
hours. After performing the test, the hose, when visually inspected 
under 7 power magnification, must reveal no visible cracks. The ozone 
resistance specifications in SAE J1403 are similar but SAE J1403 
specifies an ozone concentration of 100 ppm rather than 50 ppm. The 
agency tentatively concludes it is appropriate to update the ozone 
resistance specifications for vacuum brake hose, as it proposes to do 
for other types of brake hoses. Accordingly, NHTSA proposes to 
incorporate SAE J1403's 100-ppm ozone concentration specification into 
FMVSS No. 106.
5. Burst Strength
    The burst strength requirements in FMVSS No. 106 and SAE J1403 are 
nearly identical. Both standards specify a hydrostatic burst test at 
350 psi with no hose rupturing allowed under FMVSS No. 106 and no 
leakage or bursting allowed under SAE J1403. Given the similarities in 
the two standards, NHTSA does not propose any changes to the vacuum 
brake hose burst strength requirements/procedures in FMVSS No. 106.
6. Vacuum Deformation
    Paragraph S9.2.6, Vacuum, of FMVSS No. 106 requires that a vacuum 
brake hose, when subjected to 26 inches of Hg. for 5 minutes, not 
collapse more than \1/16\-inch as measured on the hose's outside 
diameter. SAE J1403 does not contain a corresponding, stand-alone test 
specification, although the collapse of hose as a percentage of OD is 
measured after performing the high temperature vacuum aging test 
described above. NHTSA does not propose any changes to the vacuum 
deformation requirements/procedures in FMVSS No. 106.
7. Bend Test
    FMVSS No. 106 requires that a specified length of hose be bent 
until the ends are touching, with a maximum permissible outside 
diameter (OD) collapse specified in fractional inches. SAE J1403 has a 
similar requirement, although the maximum permissible collapse is 
specified as a percentage of the un-bent OD (e.g., 20 percent, 30 
percent). It is difficult to compare the two requirements/procedures 
because the values presented in Standard No. 106 are not expressed in 
terms of OD measurement and, therefore, a percentage calculation cannot 
be made. One difference between the two standards is that SAE J1403 
excludes preformed hoses molded to fit specific applications in which 
no significant additional bending occurs when the hose is installed on 
a vehicle. Based on the information provided in each standard, it does 
not appear that either set of requirements/procedures is more stringent 
than the other. Accordingly, NHTSA does not propose any changes to the 
bending requirements/procedures in FMVSS No. 106. The agency does 
propose, however, to incorporate SAE J1403's exclusion of preformed 
hose and welcomes public comments on this issue.
8. Swell (Fuel Resistance)
    FMVSS No. 106 specifies that a brake hose specimen be filled with 
ASTM Reference Fuel A and conditioned for 48 hours, after which the 
inside diameter (ID) of the hose is required to be at least 75 percent 
of nominal ID for heavy-duty hose and 70 percent of nominal ID for 
light-duty hose. Standard No. 106 specifies use of a plug gauge to 
measure the hose's inside diameter. Following the swell test, FMVSS No. 
106 specifies subjecting the hose to 26 inches of Hg for ten minutes. 
The hose must then be examined to determine that no leakage or 
separation of the inner tube from the fabric reinforcement of the hose 
has occurred.
    SAE J1403's swell test requirements/procedures are similar, but not 
identical. First, SAE J1403 specifies use of Reference Fuel B rather 
than Reference Fuel A. Second, SAE J1403 specifies that the hose's 
inside diameter be measured with a drop ball rather than a plug gauge. 
Third, SAE J1403 specifies a 10-minute vacuum test, followed by a layer 
adhesion test with an 8 pounds-per-inch minimum separation 
specification. In contrast, FMVSS No. 106 specifies that the hose show 
no leakage or separation of the inner tube from the fabric 
reinforcement of the hose while the 10-minute vacuum test is being 
performed.
    With respect to the difference in specified fuels, as described in 
ASTM D471-98e1, Standard Test Method for Rubber Property--Effect of 
Liquids, Reference Fuel A is composed of 100 percent isooctane and 
Reference Fuel B is composed of 70 percent isooctane and 30 percent 
toluene by volume. Note 2 in the test method states that:

    The ASTM reference fuels in Table 3 have been selected to 
provide the maximum and minimum swelling effects produced by 
commercial gasolines. Reference Fuel A has a mild action on rubber 
vulcanizates and produces results of the same order as low swelling 
gasolines of the highly paraffinic, straight run type. Reference 
Fuels B, C [isooctance 50 percent, toluene 50 percent], and D 
[isooctane 60 percent, toluene 40 percent] simulate the swelling 
behaviour of the majority of commercial gasolines, with Reference 
Fuel C producing the highest swelling which is typical of highly 
aromatic premium grades of automotive gasoline.


[[Page 26396]]


    NHTSA proposes that Reference Fuel B as specified in SAE J1403 be 
used for the swell test in FMVSS No. 106. While this fuel would 
increase the severity of the test, it would not be so severe as using 
one of the other reference fuels that contain higher concentrations of 
toluene, nor as severe as some of the other reference fuels that 
represent ethanol or methanol blends of gasoline (gasohol).
    With respect to the difference in measuring instruments used to 
determine the hose's inside diameter, NHTSA favors use of a plug gauge 
because plug gauges are somewhat less susceptible to friction than 
steel drop-balls. Accordingly, NHTSA proposes that the plug gauge 
method be kept in place in TP-106 for swell testing of vacuum brake 
hoses, but welcomes comments on the merits of each constriction test 
procedure as it applies to vacuum brake hose.
    Regarding the differences in adhesion testing between the NHTSA and 
SAE standards during or after the vacuum test, NHTSA tentatively 
concludes that each standard has its benefits and drawbacks. While the 
visual check for hose collapse in FMVSS No. 106 is valid for cases in 
which the entire hose integrity has been compromised during the fuel 
soak, it is not clear that this visual check would be able to detect 
separation of multi-layer hose materials if collapse occurs only on the 
inside tube or layer. On the other hand, the SAE J1403 layer adhesion 
test does not include a specification that the hose not visibly 
collapse during the vacuum test. Visible collapse of the hose during 
the vacuum test indicates a loss of hose integrity, even if the hose 
layers remain well bonded.
    NHTSA proposes that the specifications of these two standards 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 proposes that this adhesion test only be applied to multi-layer 
hoses for two reasons. First, the agency tentatively concludes that 
single layer hose cannot be tested easily. Second, NHTSA tentatively 
concludes 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.
    In addition to the foregoing changes to FMVSS No. 106's swell test 
requirements/procedures, NHTSA also proposes to update the ASTM test 
procedure referenced in S10.7 for the swell test to the current 
revision, D471-98e1.
9. Adhesion
    FMVSS No. 106 requires that vacuum brake hose, other than wire-
reinforced hose, have a minimum layer separation strength of 8 pounds 
per inch. There are no specifications for wire-reinforced hose. There 
is a similar, 8-pound-per-inch adhesion requirement in SAE J1403, 
although the SAE standard specifically identifies the layers as ``the 
tube from the plies'' and ``the cover from the plies.'' NHTSA 
tentatively concludes that there are no substantial differences between 
these two standards. Because NHTSA is proposing to combine the adhesion 
test with the swell test, however, the agency proposes to delete the 
stand-alone adhesion test specifications for vacuum brake hose from 
FMVSS No. 106.
10. Deformation
    Paragraph S9.2.10, Deformation, of FMVSS No. 106 specifies testing 
short lengths of hose by compressing (flattening or collapsing) the 
hose to a specified dimension and then releasing the compression force. 
After five cycles, the minimum outside diameter (OD) of the hose must 
be at least a specified percentage of the original OD. SAE J1403 does 
not contain a similar set of deformation testing specifications. NHTSA 
does not propose any changes to the vacuum brake hose deformation 
requirements/specifications in FMVSS No. 106.
11. End Fitting Corrosion Resistance
    Paragraph S9.2.11, End fitting corrosion resistance, of FMVSS No. 
106 requires that vacuum brake hose end fittings show no surface base 
metal corrosion after being exposed to salt spray for 24 hours. 
Standard No. 106 provides an exception for that portion of the end 
fitting where crimping or the application of labeling information has 
caused displacement of the end fitting's protective coating. SAE J1403 
does not contain any corresponding requirements. NHTSA does not propose 
any changes to Standard No. 106's end fitting corrosion resistance 
requirements.
    The table below summarizes the differences between the vacuum brake 
hose requirements/procedures of FMVSS No. 106 and SAE J1403 and 
indicates which requirements/procedures NHTSA proposes incorporating 
into the standard.

  Table 3.--Comparison of Vacuum Brake Hose Requirements/Procedures in
                       FMVSS No. 106 and SAE J1403
------------------------------------------------------------------------
                                    Existing FMVSS
    Requirement/Procedure              No. 106              SAE J1403
------------------------------------------------------------------------
                           Vacuum Brake Hoses
``x'' Indicates Requirements/Procedures Proposed To Be Included in FMVSS
                                 No. 106
------------------------------------------------------------------------
Constriction Test...........   x   Specifications   ...  No
                                    for                   corresponding
                                    constriction          specifications
                                    at end
                                    fittings.
High Temperature Resistance.  ...  Hose bent and     x   High
                                    exposed to            temperature
                                    elevated              conditioning,
                                    temperature,          bend test,
                                    less severe           pressure test
                                    than J1403.
Low Temperature Resistance..  ...  Similar, but      x   Similar, but
                                    does not              also specifies
                                    include               175 psi
                                    pressure test.        pressure test
Ozone Resistance............  ...  Similar, 50 ppm   x   Similar, 100
                                    ozone                 ppm ozone
                                    concentration.        concentration
Burst Strength..............   x   Same...........  ...  Same
Vacuum Deformation..........   x   Limit 1/16 in.   ...  No
                                    collapse of           corresponding,
                                    hose OD under         stand-alone
                                    vacuum.               specification;
                                                          high
                                                          temperature
                                                          test has
                                                          specifications
Bend Test...................   x   Similar test,    ...  Similar test,
                                    different             different
                                    measurement.          measurement
Swell (Fuel Resistance).....   1   Similar test,     1   Similar test,
                                    Reference Fuel        Reference Fuel
                                    A, no collapse        B, layer
                                    or leakage            adhesion test
                                    permitted.            specified
Adhesion....................  ...  Similar, but is   x   Similar, but is
                                    a stand-alone         conducted
                                    test.                 after swell
                                                          test fuel soak

[[Page 26397]]

 
Deformation.................   x   Compression      ...  No
                                    test.                 corresponding
                                                          test
End Fitting Corrosion          x   Same as for      ...  No
 Resistance hose end                hydraulic             corresponding
 fittings.                          brake hose end        test
                                    fittings.
------------------------------------------------------------------------
Note 1: NHTSA proposes performing layer adhesion test once vacuum hose
  has been conditioned during swell test. NHTSA considers a stand-alone
  adhesion test unnecessary.

    The agency notes that plastic vacuum brake tubing is being used in 
automotive applications, as it has been requested to issue legal 
interpretations on the application of requirements in Standard No. 106 
to this type of material. This may lead to a situation similar to that 
for air brake hose, for which both rubber hose and plastic tubing are 
widely used and the agency is now proposing to create separate 
requirements for each type of hose. The agency is not aware of an SAE 
or other industry standard for plastic vacuum brake hose and therefore 
is not currently proposing any separate requirements for this material. 
If a suitable industry standard is developed for plastic vacuum brake 
tubing, the agency may consider adopting those requirements into 
Standard No. 106 as appropriate, as part of a future rulemaking 
activity.

D. Plastic Air Brake Tubing

    NHTSA's performance requirements and test procedures relating to 
plastic air brake tubing are located in paragraph S7., Requirements--
Air brake hose, brake hose assemblies, and brake hose end fittings, and 
paragraph S8., Test procedures--Air brake hose, brake hose assemblies, 
and brake hose end fittings. The corresponding SAE requirements/
procedures are contained in SAE Surface Vehicle Standard J844, 
Nonmetallic Air Brake System Tubing, Rev. June 1988 (SAE J844).
    Standard No. 106's requirements for plastic air brake tubing are 
the same as those for rubber air brake tubing. NHTSA tentatively 
concludes that FMVSS No. 106 does not adequately address the 
performance requirements for plastic air brake tubing because of the 
significant difference in the materials, construction, and end fittings 
of plastic air brake tubing compared with rubber air brake hose. The 
agency tentatively concludes that due to the current requirements in 
the FMCSRs, plastic air brake tubing as widely used on air-braked 
vehicles has been, up until this time, compliant with SAE J844. 
Therefore, if SAE J844 compliance is no longer required by the FMCSRs, 
as has been proposed by the FHWA, then the potential exists that the 
requirements currently in Standard No. 106 will not adequately ensure 
the continued safe performance of plastic air brake tubing.
    NHTSA proposes that the substantive requirements/procedures in SAE 
J844 be incorporated into FMVSS No. 106, including dimensional 
specifications, classifications, burst test, moisture absorption test, 
ultraviolet resistance test, cold temperature flexibility test, heat 
aging test, resistance to zinc chloride and methyl alcohol tests, 
boiling water stabilization and burst tests, cold temperature impact 
test, collapse resistance test, and hot tensile strength test. NHTSA 
proposes that two performance requirements currently in Standard No. 
106 for air brake hoses, ozone resistance and oil resistance, continue 
to be required for plastic tubing. However, for the oil resistance 
test, NHTSA proposes a new test procedure consisting of oil 
conditioning followed by a burst test, rather than the volumetric 
expansion specification currently in Standard No. 106, as a test 
condition more appropriate for plastic tubing.
    The agency also proposes incorporating the classifications and 
dimensional specifications from SAE Surface Vehicle Standard J1394, 
Metric Nonmetallic Air Brake System Tubing, Rev. April 1991, into FMVSS 
No. 106. Although not referenced by the petitioners, this standard 
contains requirements for plastic air brake tubing manufactured in 
metric sizes. NHTSA tentatively concludes that it is appropriate to 
include requirements for both metric and inch sizes of plastic air 
brake tubing.
    Plastic air brake tubing is typically sold separately from the end 
fittings and therefore it is generally not sold or supplied as an air 
brake hose assembly, with the exception of coiled hoses used between 
tractors and trailers which are often pre-assembled using permanently-
attached end fittings. In light of this, the SAE has developed separate 
standards for plastic air brake tubing and plastic air brake tubing 
assemblies and end fittings. SAE J844 contains performance requirements 
for plastic air brake tubing, while SAE Surface Vehicle Standard J1131, 
Performance Requirements for SAE J844 Nonmetallic Tubing and Fitting 
Assemblies Used in Automotive Air Brake Systems, contains performance 
requirements for plastic air brake tubing assemblies and end fittings.
    The requirements in S7 of FMVSS No. 106 were developed for rubber 
air brake hose that is sized according to internal diameter (ID). 
Paragraph S7 contains few references to plastic/nylon tubing that, 
unlike rubber air brake hose, is sized according to outside diameter 
(OD) and is a significantly different product than rubber hose. Plastic 
tubing is generally manufactured from nylon but the generic term 
plastic is used in this notice to account for other types of plastic 
that may be used for this application. As previously discussed, the 
applicability of Table III in Standard 106 was amended so that it would 
only be applicable to brake hoses made from synthetic or natural 
elastomeric rubber, thus there are no dimensional requirements for 
plastic tubing in FMVSS No. 106. NHTSA proposes that new dimensional 
requirements for plastic air brake tubing be included in Standard No. 
106 based on the dimensions currently used in SAE J844 (inch units) and 
SAE J1394 (metric units).
    Non-coiled plastic tubing is used for air system plumbing to 
connect components that maintain a basically fixed relationship during 
vehicle operation. Coiled plastic tubing is generally used in flexible 
connections such as between a tractor and a semi-trailer. By coiling a 
long length of relatively stiff plastic tubing, a flexible coiled 
arrangement is obtained. Non-coiled tubing differs from conventional 
rubber hose in that it would not be used between components that 
experience relative motion, although it would still be subjected to 
vibration and other loads.
1. Classification
    FMVSS No. 106 references Type I and Type II air brake hose and 
reusable end fittings which are required to be labeled as either ``AI'' 
or ``AII.'' SAE J844 and SAE J1394 classify plastic tubing as ``A''

[[Page 26398]]

for smaller diameter, non-reinforced tubing made from one layer of 
material, or ``B'' for larger diameter tubing made from two layers of 
material with a reinforcement braid located at the layer interface. 
Tubing is sized by the nominal OD of the tubing either in fractions of 
an inch or in millimeters. These designations are appropriate for 
plastic tubing but FMVSS No. 106 does not currently contain any 
references to Type A and B tubing or any dimensional requirements for 
plastic tubing.
    It should be noted that FMCSR Sec.  393.45(b)(ii) specifies that, 
for plastic tubing used on commercial motor vehicles, the reference to 
SAE J844 only includes Type B tubing. NHTSA proposes to update FMVSS 
No. 106 to include requirements for both Types A and B plastic tubing.
2. Dimensions and Tolerances
    SAE J844 includes a table (Table 1) that prescribes, for each 
nominal size of tubing, the ID, OD, minimum wall thickness, and 
tolerances on the ID and OD. There are no corresponding dimensions in 
FMVSS No. 106. These dimensions are safety-critical because they ensure 
that the tubing is compatible with the fittings designed for that 
tubing. Incompatibility between tubing and end fittings can, among 
other things, cause the inside diameter of the tubing to collapse. 
NHTSA agrees with the petitioners that, if there are no requirements 
for these dimensions, there is the possibility that tubing of improper 
dimensions could pull out of the end fittings or otherwise prematurely 
fail at the connections, leak because of improper sealing due to 
dimensional incompatibility with fittings, or loosen due to thermal 
expansion and contraction. Accordingly, NHTSA proposes to incorporate 
into Standard No. 106 the dimension and tolerance requirements 
contained in SAE J844.
3. One Hundred Percent Leak Test
    SAE J844 requires tubing manufacturers to subject all air brake 
tubing to a 200-psi leak test. The specific testing methods, including 
test media, rate of application, and required performance measures, are 
not specified in SAE J844 and are, therefore, determined by the tubing 
manufacturer.
    FMVSS No. 106 does not address the quality control methods that 
hose manufacturers use to ensure that all hoses installed on motor 
vehicles will meet the standard. Rather, the manufacturers of such 
components are required to certify compliance, and each brake hose or 
assembly is required to meet the standard. NHTSA tentatively concludes 
that plastic air brake tubing manufacturers will continue to perform 
quality control tests on their products, but that such requirements 
should not be included in FMVSS No. 106.
4. Burst Test
    SAE J844 specifies that tubing be stabilized at 75 degrees F for a 
period of 30 minutes to 3 hours. Pressure (of an unidentified medium, 
assumed to be air) in the tube is increased at a constant rate to reach 
a specified minimum burst pressure (specified in Table 2) within a time 
period of 3 to 15 seconds. The tubing must sustain the specified 
pressure without bursting. FMVSS No. 106 specifies using water as the 
test media, with a pressure increase rate of approximately 1,000 psi 
per minute, to a pressure of 800 psi. The specified pressures in Table 
2 of SAE J844 range from 1000 to 1200 psi for Type A tubing and 800 psi 
to 1400 psi for Type B tubing (each size of tubing has one specific 
burst pressure). Therefore, the pressure requirements in SAE J844 are 
equal to or higher than those in FMVSS No. 106. While the performance 
differences of the different test media have not been measured, it 
would appear that using air would be more appropriate for air brake 
tubing than using water. NHTSA welcomes comments on the use of air 
versus water as the test medium.
    In NHTSA' judgment, the greater pressure requirements in SAE J844 
are more rigorous than existing requirements in FMVSS No. 106. NHTSA 
proposes 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 proposes 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. NHTSA welcomes comments on the use of air versus water as the test 
medium.
5. Moisture Absorption
    SAE J844 specifies that a tubing specimen be conditioned for 24 
hours at 230 degrees F, immediately weighed, and then subjected to 100 
percent relative humidity for 100 hours at 75 degrees F. Within five 
minutes of removal from the humidity chamber, surface moisture is wiped 
from all surfaces of the tubing and the tubing is weighed. The moisture 
absorption shall not exceed 2 percent by weight. FMVSS No. 106 does not 
have a corresponding test. NHTSA proposes incorporating the moisture 
absorption specification from SAE J844 into FMVSS No. 106.
6. Ultraviolet Resistance
    SAE J844 specifies that the tubing be placed in a Q-Panel QUV test 
apparatus equipped with Philips Type UVS-340 bulbs. If the test 
apparatus is equipped with a ``Solar Eye,'' the bulbs need not be 
rotated and the irradiance should be set at 0.85; however, all bulbs 
should be discarded after 4800 hours maximum or if they fall below the 
0.85 irradiance level, whichever occurs first. If the test apparatus is 
not equipped with a ``Solar Eye,'' the bulbs must be rotated every 400 
hours maximum, per the apparatus manufacturer and ASTM G 53. Bulbs used 
in such an apparatus must be discarded after 1600 hours of use.
    The samples are placed in the sample racks of the test apparatus 
and are exposed for 300 hours at a temperature of 113 degrees F, with 
the surface of the specimen mounting plate located no more than 2 
inches from the bulbs. The samples are rotated according to ASTM D 4329 
except the rotation is each 96 hours rather than weekly. No humidity 
other than ambient is introduced. Immediately after the samples are 
removed from the ultraviolet light test apparatus, they are subjected 
to an impact test using a device depicted in Figure 1 of SAE J844. The 
tubing samples are then cooled to 75 degrees F and subjected to a burst 
test, with a minimum burst pressure that is at least 80 percent of the 
value assigned to the tubing based on the tubing's outside diameter as 
indicated in Figure 2 of SAE J844.
    NHTSA notes that in November 1973 (38 FR 31302), NHTSA deleted the 
ultraviolet light resistance tests for air brake hoses in Standard No. 
106, stating that sufficient data had not been generated to support a 
minimum performance requirement. However, NHTSA tentatively concludes 
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 also notes 
that air brake tubing is installed on heavy vehicles in locations that 
are exposed to naturally-occurring ultraviolet light. Therefore, NHTSA 
proposes to incorporate SAE J844's ultraviolet resistance test into 
FMVSS No. 106, although the agency proposes to reference the apparatus 
specified in ASTM G154-00, Standard Practice for Operating Fluorescent 
Light Apparatus for UV Exposure of Nonmetallic

[[Page 26399]]

Materials, rather than the one specified in ASTM G53 because ASTM G154-
00 is an updated version of ASTM G53. NHTSA also proposes 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.
7. Cold Temperature Flexibility
    SAE J844 specifies tubing to be conditioned at 230 degrees F for 24 
hours. Within 30 minutes of removal from the oven, the tubing is placed 
in a cold chamber at minus 40 degrees F and conditioned for 4 hours. A 
test cylinder with a radius equal to 6 times the nominal OD of the 
tubing is also conditioned at minus 40 degrees F for 4 hours. The 
tubing and test cylinder are removed from the cold chamber and the 
tubing is bent 180 degrees around the test cylinder within a period of 
4 to 8 seconds. The tubing must show no signs of fracture.
    FMVSS No. 106 also contains a low temperature resistance test 
procedure. The FMVSS No. 106 procedure differs in that the hose is bent 
around the test cylinder prior to being conditioned in the cold 
chamber; the cold conditioning is for 70 hours; and there is no high-
temperature preconditioning. The table in paragraph S7 (Table IV) 
includes dimensions for the test cylinder radius for each nominal size 
of hose. Table IV references hose size by nominal diameter, and does 
not differentiate between hose, which is sized by inside diameter, and 
tubing, which is sized by outside diameter. Applying the test cylinder 
radii in Table IV to the nominal outside diameter of tubing, and then 
comparing these values to the test cylinder radii in SAE J844, reveals 
that the test cylinder radii in SAE J844 are smaller and, therefore, 
SAE J844 provides a more stringent test condition in terms of bend 
radius than does FMVSS No. 106.
    The test conditions of ``cold temperature flexibility'' in SAE J844 
do not correspond to the ``low temperature resistance'' test in FMVSS 
No. 106. SAE J844 is a test to evaluate the crack resistance of tubing, 
subjected to bending while in a cold state, while the FMVSS No. 106 
test condition is an evaluation of pre-bent tubing's resistance to 
cracking when subjected to cold temperatures. Because SAE J844 is more 
rigorous, NHTSA proposes substituting it for the current test in FMVSS 
No. 106. NHTSA tentatively concludes that the time period of 4 to 8 
seconds to accomplish the bending of the tubing is appropriate for this 
test because the bending is done by hand and is therefore subject to 
some variability. Specifying the 4 to 8 second time period will 
preclude the need for specialized bending apparatus that can meet a 
specific timing specification.
8. Heat Aging
    SAE J844 includes three different heat aging tests, which specify 
use of three separate samples of the same tubing. A tubing sample is 
subjected to one of the aging tests described below, then subjected to 
the burst test at room temperature, with a minimum burst strength of 80 
percent of a specified value.
    The first test is to bend a section of tubing 180 degrees around a 
test cylinder with a diameter equal to two times the tubing's minimum 
bend radius, as specified in the standard. The tubing and test cylinder 
are conditioned for 72 hours at 230 degrees F and then removed to cool 
at 75 degrees F. Within 30 minutes after stabilizing at 75 degrees F, 
the tubing is straightened within a time period of four seconds. The 
tubing is then bent 180 degrees in the opposite direction within a time 
period of 4 to 8 seconds.
    The second test is to condition the tubing at 230 degrees F for 72 
hours, then remove and cool the tubing to 75 degrees F. Within 30 
minutes after stabilizing at 75 degrees F, the tubing is subjected to 
an impact test as specified in the standard.
    The third test involves conditioning the tubing by immersing it in 
boiling water for 2 hours, then removing and cooling it to 75 degrees 
F. Within 30 minutes after stabilizing at 75 degrees F, the tubing is 
subjected to an impact test as specified in the standard.
    FMVSS No. 106 does not have corresponding test procedures. The high 
temperature resistance test (S8.1) evaluates a hose for resistance to 
visible cracking after being conditioned at 212 degrees F for 70 hours 
and then straightened. There is no burst (pressure) strength 
requirement. NHTSA proposes incorporating the SAE J844 test procedures 
for plastic air brake tubing into FMVSS No. 106.
9. Zinc Chloride Resistance
    SAE J844 specifies that tubing be bent around a test cylinder and 
immersed in a 50 percent by weight (specific gravity of 1.576 or a 
Baume rating of 53 degrees at 60 degrees F) aqueous solution of zinc 
chloride for 200 hours at 75 degrees F. After removal from the 
solution, the tubing must show no evidence of cracking on the outside 
diameter. FMVSS No. 106 specifies that a hose assembly be immersed in a 
50 percent zinc chloride aqueous solution for 200 hours, with no 
visible cracks permitted when viewed with 7-power magnification. SAE 
J844's zinc chloride test procedures are more rigorous due to the 
bending of the tubing during the conditioning. Accordingly, NHTSA 
proposes to incorporate the zinc chloride resistance performance 
requirements and test procedures from SAE J844 into FMVSS No. 106.
10. Resistance to Methyl Alcohol Resistance
    SAE J844 specifies that the tubing be bent around a test cylinder 
and then immersed in 95 percent methyl alcohol for 200 hours at 75 
degrees F. After removal from the solution, the tubing must show no 
evidence of cracking. This test ensures that air brake tubing is not 
susceptible to damage from alcohol that is sometimes introduced into 
air brake systems during extreme cold weather conditions, or from 
windshield washer fluid containing alcohol that may spill onto brake 
tubing. There is no corresponding test procedure/performance 
requirement in FMVSS No. 106, and NHTSA proposes to incorporate the one 
specified in SAE J844. NHTSA also welcomes comments on the suitability 
of adopting this test procedure/performance requirement for rubber air 
brake hoses, since they are also susceptible to alcohol exposure for 
the same reasons.
11. Stiffness
    SAE J844 specifies that an 11-inch long sample of tubing be slipped 
over a rod to maintain the hose in a straight position within plus or 
minus \1/8\ inch. The tubing and rod are conditioned at 230 degrees F 
for 24 hours, then removed and cooled to 75 degrees F. Within 30 
minutes after stabilizing at 75 degrees F, the rod is removed and 
tubing is subjected to a stiffness test as outlined in the standard. 
The tubing must require no more that the specified amount of force to 
deflect 2 inches. This test ensures that the flexibility of the tubing 
is not reduced when the tubing is subjected to elevated temperatures. 
An increase in stiffness after exposure to elevated temperatures 
indicates that the tubing is susceptible to kinking or embrittlement 
under this condition. Because Standard No. 106 does not contain a 
similar set of procedures/requirements, NHTSA proposes to incorporate 
the stiffness procedures/

[[Page 26400]]

requirements from SAE J844 into FMVSS No. 106.
12. Boiling Water Stabilization and Burst Test
    SAE J844 specifies that the tubing be immersed in boiling water for 
2 hours. The tubing is then removed from the water and subjected to a 
burst test at room temperature. The standard specifies a minimum burst 
strength of 80 percent of the value assigned to the tubing based on the 
tubing's nominal outside diameter. NHTSA tentatively concludes that 
this test condition is redundant because a similar boiling water 
conditioning test, followed by impact and burst tests, is already 
specified by the third heat aging test, as described above. FMVSS No. 
106 has no corresponding test procedure. Because NHTSA is already 
proposing to incorporate the heat aging test from SAE J844, the agency 
does not propose to also incorporate SAE J844's stand-alone boiling 
water stabilization and burst test.
13. Cold Temperature Impact
    SAE J844's cold temperature impact test specifies the use of 10 
separate samples of air brake tubing. Five samples are conditioned for 
24 hours at 230 degrees F, and the other five are conditioned in 
boiling water for 2 hours. All samples and the impact test apparatus 
are then conditioned at minus 40 degrees F for 4 hours. Each sample is 
then subjected to the impact test per Figure 1, with no visible cracks 
permitted. Each sample is then warmed to 75 degrees F and, within 30 
minutes of stabilization at this temperature, a burst test conducted. 
Each tubing sample must withstand 80 percent of the specified burst 
strength. If any one of the samples fails these tests, the entire test 
sequence is repeated using twenty samples. If any one of these twenty 
samples fails, then the entire manufacturing lot is to be rejected. 
This test evaluates the resistance of the tubing to cold temperature 
fracturing. FMVSS No. 106 does not have corresponding test procedures/
performance requirements.
    In an August 1970 notice of proposed amendment to FMVSS No. 106 (35 
FR 13738), NHTSA's predecessor agency, the National Highway Safety 
Bureau, addressed the issue of a sampling approach in testing 
standards. That notice indicated that the SAE approach, which includes 
testing of several samples and then retesting additional samples if 
initial failures are found, is not an essential methodology to 
demonstrate non-compliance. Rather, the agency indicated that it 
favored testing one brake hose sample to determine compliance. 
Manufacturers, on the other hand, should or may conduct testing on 
multiple samples as part of their quality control procedures to 
determine whether continued failures exist such as to demand rejection 
of an entire manufacturing lot. NHTSA tentatively concludes that it is 
still preferable to subject only one sample to a particular set of 
testing procedures for compliance purposes. Accordingly, the agency 
proposes that only one plastic brake tubing sample be subjected to the 
cold impact test procedures contained in SAE J844. With this one 
modification, NHTSA proposes to incorporate the cold impact test 
procedures/performance requirements from SAE J844 into FMVSS No. 106.
14. Adhesion Test
    SAE J844 specifies that Type B, reinforced tubing, be subjected to 
an adhesion test. A helical sample \1/4\ inch wide and with a length 
equal to five times the circumference of the tubing is cut from the 
tubing. With the tubing sample at a temperature of 75 degrees F, a 
knife blade is used to initiate separation at the braid interface. 
Further attempts to separate the sample must result in no separation 
over the entire length of the test sample other than at points at which 
the braid is present. SAE J844 does not include any specifications for 
Type A, non-reinforced tubing because this type of hose is only 
manufactured from one layer. Standard No. 106 presently requires that 
hose have a minimum adhesion strength of 8 pounds per linear inch of 
hose.
    NHTSA tentatively concludes that the ``no separation'' performance 
requirement in SAE J844 would be unenforceable because during a 
destructive test the tubing will ultimately fail at some point during 
the test. NHTSA tentatively concludes that the existing Standard No. 
106 minimum adhesion requirement of 8 pounds per linear inch is 
suitable for rubber air brake hose. Given the SAE J844 ``no 
separation'' specification for Type B plastic tubing, however, NHTSA 
proposes that a higher minimum adhesion requirement is appropriate for 
that type of tubing. NHTSA therefore proposes a minimum separation 
value of 25 pounds per linear inch for Type B plastic tubing, which the 
agency tentatively concludes is severe enough to ensure that an 
adequate bond exists between the tubing layers but not so high as to 
present enforcement concerns. Accordingly, NHTSA proposes that the 
adhesion test procedures/performance requirements for Type B tubing in 
SAE J844 be incorporated into FMVSS No. 106, with a minimum separation 
strength of 25 pounds per linear inch. Rather than specifying a stand-
alone adhesion test, however, NHTSA is proposing to incorporate SAE 
J844's heat aging adhesion test, which is described below. With respect 
to Type A tubing, because such tubing is typically manufactured from a 
single extrusion of nylon with no internal layers, the agency does not 
believe it is necessary to specify an adhesion test for that type of 
tubing.
    NHTSA proposes to deviate from SAE J844's test procedure because it 
appears that it would be difficult to mount the test specimen in a 
tension testing machine if the specimen is cut from a \1/4\-inch wide 
helical section of tubing. NHTSA proposes that a 1-inch length of 
tubing be cut lengthwise and two flaps of material be cut using a sharp 
knife so that the test sample can be clamped in the machine. The 
adhesion test for air brake hose that uses a rotating mandrel to 
support the inner layers of the hose was considered for tubing but does 
not appear to be practical for tubing since it would be difficult to 
separate (cut) the outer layer of the tubing from the inner layer with 
the inner layer of the tubing in an intact, round shape. NHTSA welcomes 
comments on the proposed adhesion test procedures/performance 
requirements.
15. Heat Aging and Adhesion Test
    SAE J844 specifies that a Type B tubing sample be conditioned in 
the first heat aging test (bend tubing, heat conditioning, and re-bend 
tubing after cooling) and then subjected to the adhesion test, detailed 
above. Type A tubing is not subjected to this test. FMVSS No. 106 does 
not have a corresponding set of test procedures/performance 
requirements. NHTSA proposes to incorporate the heat aging adhesion 
test procedures from SAE J844, but that the minimum adhesion 
performance requirement for Type B tubing be raised from 8 pounds per 
linear inch to 25 pounds per linear inch.
16. Collapse Resistance
    SAE J844 specifies that three test samples of specified length be 
prepared and the minor outside diameter (OD) be measured. The minor OD 
is the smallest outside diameter of the tubing measured at the center 
of the sample, typically located 90 degrees from the natural lay line 
of the tubing. The samples are installed on a specified bend test 
fixture and, following the natural bend of the tubing, each tube is 
bent 180 degrees to the minimum kink radius listed in the standard. The 
samples are conditioned

[[Page 26401]]

at 200 degrees F for 24 hours and then cooled to room temperature (75 
degrees F) and, while still installed on the bend fixture, the minor OD 
is measured. The minor OD collapse of the heat-conditioned samples must 
not exceed 20 percent of the initial minor OD. FMVSS No. 106 does not 
contain corresponding test procedures/performance requirements.
    NHTSA proposes to incorporate the collapse resistance test 
procedures/performance requirements from SAE J844 into FMVSS No. 106, 
with two changes. First, the agency proposes to specify that only one 
sample be tested rather than three. Second, NHTSA notes that the 
minimum kink radii in Table 3 of SAE J844 represents the minimum 
unsupported bend radii for tubing as installed on a vehicle while the 
test bend radii in Table 2 of that standard represent the minimum bend 
radii for supported tubing during applicable test procedures. NHTSA 
tentatively concludes that because heavy vehicle manufacturers are 
aware that such installation criteria are included in SAE J844 there is 
no need to incorporate them into FMVSS No. 106. NHTSA welcomes public 
comments on both of these proposed modifications.
17. Oil Resistance
    SAE J844 does not include an oil resistance test as specified by 
FMVSS No. 106. The oil test is used to measure the volumetric expansion 
of specimens prepared from the inner and outer layers of a hose, after 
immersion in ASTM No. 3 oil at 212 degrees F for 70 hours, with a 
maximum permissible volumetric expansion of 100 percent. While such a 
test is appropriate for the type of materials used in elastomeric, 
synthetic rubber air brake hoses, NHTSA tentatively concludes 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 is aware of a problem that was encountered several years ago 
with pre-assembled air brake tubing assemblies used for tractor-trailer 
connections supplied by one manufacturer. This particular product, when 
subjected to conditioning in oil, would undergo material property 
changes that resulted in failure (dissolution) of the tubing. The 
manufacturer of the tubing assemblies petitioned NHTSA to request that 
coiled air brake tubing assemblies be exempt from the oil resistance 
requirements in Standard No. 106. NHTSA ultimately denied this request 
and stated in the denial (58 FR 38346) that coiled air brake tubing 
assemblies are subjected to elevated temperatures and exposed to oil. 
The agency notes that this particular product was not compliant with 
SAE J844.
    NHTSA tentatively concludes it is critical that plastic air brake 
tubing be resistant to oil exposure. Oil can be introduced into air 
brake systems due to air compressor leakage, and exposed portions of 
tubing are subject to oil and grease contamination from sources such as 
hydraulic work equipment mounted on vocational trucks, axle lubricant 
leakage, and fifth wheel lubrication. Therefore, NHTSA proposes 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 involves 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 proposes that the tubing 
not burst at less than 80 percent of the burst pressure listed in Table 
2 of SAE J844. This required performance is the same as that specified 
in SAE J844 for the boiling water stabilization and burst test. NHTSA 
tentatively concludes that using an 80 percent value for the oil test 
is appropriate given that the tubing is pre-conditioned in oil, similar 
to the preconditioning of the boiling water test, and notes that the 
tubing would not be required to have the 100 percent burst strength 
required for non-conditioned tubing tested at room temperature. NHTSA 
welcomes comments on this proposed test procedure in lieu of the 
existing Standard No. 106 requirement that limits volumetric expansion 
of the material during oil conditioning.
18. Ozone Resistance
    SAE J844 does not include an ozone resistance test as specified by 
FMVSS No. 106. Standard No. 106 specifies bending a hose around a test 
cylinder and conditioning it in a test chamber at 50-ppm ozone 
concentration at 104 degrees F for 70 hours. After performing this 
test, no visible cracks may be detected when viewed under 7-power 
magnification. The agency notes that the ozone test for hydraulic brake 
hose in SAE J1401 specifies an ozone concentration of 100 ppm and that, 
as noted above, NHTSA is proposing to increase the ozone concentration 
requirements for all types of brake hose covered by FMVSS No. 106. 
Accordingly, NHTSA proposes that the ozone test that is currently 
specified in Standard No. 106 continue to be applied to plastic air 
brake tubing at the higher ozone concentration level of 100 ppm.
    The table below summarizes the differences between the plastic air 
brake tubing requirements/procedures of FMVSS No. 106 and SAE J844 and 
indicates which requirements/procedures NHTSA proposes incorporating 
into the standard.

 Table 4.--Comparison of Nylon Air Brake Tubing Requirements/Procedures
                      in FMVSS No. 106 and SAE J844
------------------------------------------------------------------------
                                    Existing FMVSS
    Requirement/Procedure              No. 106               SAE J844
------------------------------------------------------------------------
                        Plastic Air Brake Tubing
``x'' Indicates Requirements/Procedures Proposed to be Included in FMVSS
No. 106. A new section would be added with performance requirements/test
  procedures for plastic air brake tubing. Some existing requirements/
             procedures for air brake hose would also apply.
------------------------------------------------------------------------
100 Percent Leak Test.......   x   Not Specified..  ...  Each lot to be
                                                          tested.
Classification..............  ...  Type AI or AII    x   Type A or B
                                    air hose.             plastic air
                                                          brake tubing.
Dimensional Specifications..  ...  None...........   x   J844 (inch) and
                                                          J1394 (metric)
                                                          dimensions for
                                                          plastic
                                                          tubing.
Burst Test..................  ...  800 psi           x    Strength based
                                    requirement.          on tubing size
                                                          and type,
                                                          minimum is 800
                                                          psi.
Moisture Absorption.........  ...  None...........   x   Not to exceed 2
                                                          percent.
Ultraviolet Resistance......  ...  None...........   x   300 hour
                                                          exposure
                                                          followed by
                                                          impact test.

[[Page 26402]]

 
Cold Temperature Flexibility  ...  Low temperature   x   Cold
                                    resistance but        conditioning
                                    not                   followed by
                                    flexibility.          bending around
                                                          test cylinder.
Heat Aging..................  ...  Does not          x   Three separate
                                    include burst         test
                                    test.                 procedures
                                                          followed by
                                                          burst test.
Zinc Chloride Resistance....  ...  Similar but       x   Similar, tubing
                                    tubing is not         is conditioned
                                    bent during           while bent
                                    test.                 around test
                                                          cylinder.
Methyl Alcohol Resistance...  ...  None...........   x   Tubing bent
                                                          around test
                                                          cylinder and
                                                          conditioned in
                                                          alcohol for
                                                          200 hours.
Stiffness...................  ...  None...........   x   Stiffness of
                                                          tubing after
                                                          conditioning
                                                          at elevated
                                                          temperature.
Boiling Water Stablization    ...  None...........  ...  Considered
 and Burst Test.                                          redundant
                                                          since more
                                                          severe test
                                                          condition
                                                          included in
                                                          heat aging
                                                          test.
Cold Temperature Impact.....  ...  None...........   x   Cold
                                                          conditioning,
                                                          impact test,
                                                          and burst
                                                          test.
Adhesion Test...............  ...  8 lbs. per        1   Type B tubing
                                    linear inch,          only, no
                                    for any air           separation
                                    brake hose.           permitted.
Heat Aging Adhesion Test....  ...  None...........   1   Type B tubing
                                                          only, heat
                                                          aging and
                                                          adhesion test.
                                                          No separation
                                                          permitted.
Collapse Resistance.........  ...  None...........   x   Max. 20 percent
                                                          collapse after
                                                          high temp.
                                                          conditioning
                                                          bent around
                                                          test cylinder.
Ozone Resistance............   2   Same as air      ...  None.
                                    brake hose, 50
                                    ppm.
Oil Resistance..............   3   Same as air      ...  None.
                                    brake hose.
------------------------------------------------------------------------
Note 1: NHTSA proposes a 25 lbs. per inch adhesion strength instead of
  ``no separation.''
Note 2: NHTSA proposes 100 ppm ozone concentration.
Note 3: NHTSA proposes an oil soak and burst test for plastic tubing.

E. Plastic Air Brake Tubing Assemblies and End Fittings

    NHTSA's performance requirements and test procedures relating to 
plastic air brake tubing assemblies and end fittings are located in 
paragraph S7., Requirements--Air brake hose, brake hose assemblies, and 
brake hose end fittings, and paragraph S8., Test procedures--Air brake 
hose, brake hose assemblies, and brake hose end fittings, of FMVSS No. 
106. The corresponding SAE performance requirements/test procedures are 
contained in SAE Surface Vehicle Standard J1131, Performance 
Requirements for SAE J844 Nonmetallic Tubing and Fitting Assemblies 
Used in Automotive Air Brake Systems, Rev. August 1998 (SAE J1131). 
SAE's end fitting performance requirements/test procedures are located 
in SAE Surface Vehicle Standard J512, Automotive Tube Fittings Rev. 
October 1980 (SAE J512) and SAE Surface Vehicle Standard J246, 
Spherical and Flanged Sleeve (Compression) Tube Fittings Rev. March 
1981 (SAE J246).
    This section addresses performance requirements and test procedures 
for plastic air brake tubing assemblies and end fittings. The previous 
section compared FMVSS No. 106 to SAE J844 and only addressed the 
properties of the tubing and not the properties of tubing assemblies or 
end fittings. SAE J1131 evaluates the performance of SAE J844 tubing 
when used in an assembly with either permanently-attached or reusable 
end fittings.
    NHTSA proposes to incorporate the following end fitting performance 
requirements/test procedures from SAE J1131 into Standard No. 106: the 
hot tensile strength test, the conditioned pull test, the vibration 
leak test, the proof and burst test, the fitting compatibility test, 
and the serviceability test. The serviceability test specifies that an 
end fitting, after five assembly and disassembly cycles, not leak more 
than 25 cm3/min. and NHTSA proposes that this test will only 
apply to fittings that use a threaded retention nut. Push-to-connect 
fittings are often believed to result in damage to the tubing upon 
disassembly and therefore may not be able to meet this specification. 
When such fittings are disassembled, the end of the tubing can be cut 
off if there is enough slack in the assembly, or a new section of 
tubing will need to be fitted for reinstallation.
    The agency also proposes specifying constriction testing for 
plastic air brake tubing assemblies as such testing is already 
specified for air brake hose assemblies under Standard No. 106.
    NHTSA proposes including the current corrosion resistance test in 
FMVSS No. 106, as applied to all types of brake hose fittings (i.e., 
hydraulic, vacuum, air), for fittings used with plastic air brake 
tubing. End fitting corrosion specifications are included in SAE J246 
and SAE J512 rather than SAE J1131, and these specifications are 
different than those currently in FMVSS No. 106, with the SAE test 
procedures including longer exposure to salt spray but less severe 
performance requirements for permissible corrosion.
    A detailed discussion of the differences between the performance 
requirements/test procedures of SAE J1131, SAE J246, SAE J512, and 
FMVSS No. 106 as they relate to plastic air brake tubing assemblies and 
end fittings follows, along with the agency's proposed resolution of 
those differences.
1. Tensile Strength
    FMVSS No. 106 specifies that an air brake hose assembly for use 
between either the frame and the axle, or a towing and towed vehicle, 
meet a longitudinal pull test, at a 1 inch per minute force application 
rate without separating from its end fittings at the following force 
levels: 250 pounds for \1/4\ inch or less, or 6mm or less, nominal ID; 
325 pounds for more than \1/4\ inch or 6mm nominal ID. A hose assembly 
used in any other application must withstand force levels of: 50 pounds 
for \1/4\ in or less, or 6 mm or less, nominal ID; 150 pounds for \3/8\ 
inch, \1/2\ inch, or 10 mm to 12 mm, nominal ID; and 325 pounds if the 
hose assembly is larger than \1/2\ inch or 12 mm nominal ID. A coiled 
nylon tube assembly may either meet these requirements or, 
alternatively,

[[Page 26403]]

may meet the requirements in FMCSR 393.45.
    While FMVSS No. 106's air brake hose performance requirements and 
test procedures are currently presented in terms of nominal inside 
diameter, the agency notes that plastic air brake tubing is sized 
according to nominal outside diameter. In an August 7, 1974, amendment 
to FMVSS No. 106 (39 FR 28436), NHTSA responded to a petition from 
Samuel Moore Company in which the petitioner contended that it was 
appropriate to base Standard No. 106's tensile strength requirements on 
the nominal inside diameter of the tubing rather than on the tubing's 
nominal outside diameter. The petitioner argued that because \3/8\-inch 
nominal OD plastic tubing has an inside diameter of \1/4\-inch and 
provides the same air flow capability as a \1/4\-inch nominal ID rubber 
hose, they should be subject to the same tensile strength requirements. 
In response to the petition, NHTSA decided to base the tensile strength 
requirements on the nominal inside diameter of the hose or tubing. 
Because plastic air brake tubing is labeled according to its nominal 
outside diameter, however, NHTSA now proposes to specify tensile 
strength requirements in the same manner to minimize confusion.
    Unlike FMVSS No. 106, SAE J1131 does not contain a stand-alone 
tensile strength test for air brake tubing assemblies. Instead, SAE 
J1131 specifies tensile strength testing after an air brake tubing 
assembly has been assembled and pre-conditioned in some manner. The SAE 
tensile strength performance requirements for pre-conditioned tubing 
assemblies are not as rigorous as NHTSA's stand-alone requirements. 
Although the agency proposes to incorporate SAE J1131's tensile 
strength requirements, NHTSA also proposes to retain the stand-alone 
tensile strength requirements already present in FMVSS No. 106, with 
the modifications discussed below.
    Standard No. 106's tensile strength requirements provide an 
alternative set of requirements for coiled nylon tubing. Coiled nylon 
tubing may either meet the tensile strength requirements in FMVSS No. 
106 or, alternatively, may meet the requirements in section 393.45 of 
the FMCSRs. FMCSR Sec.  393.45, in turn, references the tensile 
strength requirements of SAE J844. The agency notes, however, that SAE 
J844 does not contain tensile strength requirements for end fitting 
retention. The end fitting retention requirements are contained in SAE 
J1131, which is not referenced in FMCSR Sec.  393.45.
    Coiled nylon tubing assemblies, by design, provide that tensile 
loads on these assemblies are spread out over the long length of the 
hose in its coiled form, and thus large amounts of relative motion, 
such as between a tractor and a semi-trailer, are not expected to 
result in significant tensile load on the end fittings that would pull 
the tubing out of the fitting. Nevertheless, NHTSA tentatively 
concludes that the potential exists for the supply and control air 
lines connecting tractors and semi-trailers to 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 
cord. The agency also notes that these air lines are completely exposed 
to the elements, are frequently connected and disconnected, and may be 
subject to various amounts of stretching depending on the physical 
dimensions of the trailers that are towed.
    Despite these potential hazards in the operating environment of 
coiled nylon tubing, however, FMVSS No. 106, as presently constituted, 
provides no tensile strength requirements for coiled nylon tubing 
assemblies if the optional compliance with SAE J844 as referenced in 
Sec.  393.45 is exercised. In contrast, small, \1/8\-inch air brake 
tubing is essentially prohibited from use in air brake systems because 
of its inability to meet Standard No. 106's 50-pound tensile strength 
requirement, even though the application of this tubing would typically 
be inside the truck cab and routed to protect it from damage. As 
discussed below, NHTSA proposes to correct this disparity in treatment 
by requiring coiled nylon tubing to meet SAE J1131's end fitting 
retention requirements and by lowering the tensile strength 
requirements for tubing with relatively small nominal outside 
diameters. The agency proposes to lower the tensile strength 
requirement for \1/8\-inch nominal OD tubing from 50 pounds to 35 
pounds and, for \5/32\-inch OD tubing, from 50 pounds to 40 pounds.
    The agency proposes to retain the existing FMVSS No. 106 tensile 
strength requirements for air brake tubing assemblies used between a 
frame and an axle, or between a towed and a towing vehicle, of 250 
pounds for a \3/8\-inch or less, or 10 mm or less, in nominal outside 
diameter, and 325 pounds for a tubing assembly larger than \3/8\-inch 
or 10 mm in nominal outside diameter. With respect to plastic air brake 
tubing assemblies used for any other purpose, the agency proposes to 
require a tensile strength of: 35 pounds for tubing with a nominal 
outside diameter of \1/8\ inch or less (3 mm or less); 40 pounds for 
tubing with a nominal outside diameter of \5/32\ inch (4 mm); 50 pounds 
for tubing with a nominal outside diameter between \3/16\-inch and \3/
8\-inch (between 5 mm and 10 mm); 150 pounds for tubing with a nominal 
outside diameter between \1/2\-inch and \5/8\-inch (between 11 mm and 
16 mm); and 325 pounds for tubing with a nominal outside diameter 
larger than \5/8\-inch (16 mm).
2. Hot Tensile Strength
    SAE J1131 specifies that a 6-inch long tubing assembly be placed in 
a tensile testing machine, with the lower 4 inches of the assembly 
submerged in boiling water for 5 minutes. The assembly is then pulled 
at a rate of 1 inch per minute. The required performance is either 50 
percent elongation of the hose without end fitting separation or the 
assembly must sustain a specified tensile load. Standard No. 106 does 
not have a corresponding test condition. Compared to the tensile 
strength requirements in FMVSS No. 106, the end fitting separation 
strength requirements in SAE J1131 are lower, but Standard No. 106's 
requirements are for non-conditioned tubing assemblies. NHTSA proposes 
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 proposes to specify tensile load values for metric sized 
plastic brake tubing.
3. Conditioned Pull Test
    SAE J1131 specifies that a tubing assembly undergo four temperature 
cycles of a minus 40 degree F cold soak for 30 minutes, normalizing at 
75 degrees F, immersion in boiling water for 15 minutes and normalizing 
at 75 degrees F. After four complete cycles of temperature 
conditioning, the tubing assembly is subjected to a tensile test. The 
required performance is the same as for the hot tensile strength test 
above. This test evaluates the tubing's resistance to pulling out of 
its end fittings when subjected to thermal cycling. Equivalent 
performance requirements/test procedures are not included in FMVSS No. 
106. NHTSA proposes that these performance requirements/test procedures 
be incorporated into Standard No. 106.
4. Vibration Leak Test
    SAE J1131 specifies that an 18-inch long hose assembly be subjected 
to one million cycles on a vibration machine with one end of the hose 
fixed and the other end stroked 0.5 inches

[[Page 26404]]

perpendicularly to the hose centerline at a rate of 600 cycles per 
minute, with \1/2\ inch of slack in the hose. The hose is subjected to 
120-psi air pressure during the test, and the test chamber temperature 
is initially 220 degrees F. After 250,000 cycles, the temperature is 
decreased to minus 40 degrees F. This temperature cycle is repeated 
after 500,000 cycles. The hose assembly is instrumented to measure 
leakage during the test. There are two performance requirements. First, 
the assembly must not leak at a rate greater than 50 cm\3\ per minute 
at minus 40 degrees F or greater than 25 cm\3\ per minute at 75 degrees 
F. Second, the attaching nut at each fitting cannot move when 20 
percent of the original tightening torque is re-applied to the nut. 
FMVSS No. 106 has a leak test (S8.7), but it does not specify 
preconditioning of the hose by vibration, temperature, or other means, 
nor does it address fitting tightness after such conditioning. End 
fitting nut tightness is applicable to end fittings that can be 
disassembled such that new sections of tubing can be used with the 
existing fitting components, other than the compression sleeve and the 
tube support that are renewed when new tubing is installed. Swaged or 
crimped, permanently-attached fittings which cannot be disassembled for 
reuse, and push-to-connect fittings which can be reused but do not use 
a nut to secure the hose or tubing, are exempt from the nut tightness 
requirement.
    The SAE J1131 performance requirements/test procedures ensure 
adequate end fitting performance to resist vibration and temperature 
cycling. NHTSA proposes that most of these performance requirements/
test procedures be incorporated into FMVSS No. 106.
5. Proof and Burst Test
    SAE J1131 specifies proof and burst tests to evaluate end fitting 
retention. The test apparatus includes a suitable hydraulic pressure 
source of an unspecified medium. Tubing samples are prepared with 12 
inches of free hose length along with the fittings to be evaluated. One 
end of the assembly is plugged and the other end is attached to the 
pressure source. At a temperature of 75 degrees F, the pressure is 
increased to proof pressure and held for 30 seconds. The proof pressure 
is defined as one-half of the burst pressure specified in SAE J844. 
Pressure is then increased at a rate such that the specified burst 
pressure is achieved within 3 to 15 seconds. The fittings must not 
separate from the tubing and no visible leaks are permitted at less 
than the specified burst pressure. While FMVSS No. 106 contains leakage 
and burst performance requirements/test procedures, as detailed above, 
the burst pressures specified are lower than those in SAE J844 or SAE 
J1131. NHTSA proposes 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 proposes 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.
6. Serviceability Test
    SAE J1131 specifies a serviceability test to evaluate end fitting 
performance for reusable fittings after repeated assembly and 
disassembly. Tubing samples are prepared with 12 inches of free hose 
length, following the fitting manufacturer's recommendations for 
assembly of the end fittings. The fittings are then disassembled and 
reassembled a minimum of five times. The tubing assembly is then 
subjected to 120 psi of air at 75 degrees F, with resulting leakage not 
greater than 25 cm\3\ per minute.
    When flanged-sleeve fittings have been fitted in a plastic tubing 
assembly that requires replacement, the old tubing is removed by 
loosening the retaining nut on the fitting. A new section of tubing is 
cut from a bulk supply of tubing, new ferrules (compression sleeves 
that fit on the outside of the tubing) and tube supports (internal 
sleeves that fit inside the tubing) are installed at each end of the 
replacement tubing, and the new tubing is installed. The other 
components of the end fittings can be reused. For other types of 
repairs, such as replacement of a valve to which the tubing is 
connected, the tubing is disconnected in the same way. The portion of 
the fitting that threads into the valve can be removed and reinstalled 
on the replacement valve, and the tubing can then be reinstalled on the 
new valve using the existing ferrule that remains permanently attached 
to the tubing. The serviceability performance requirements/test 
procedures in SAE J1131 are a measure of the fitting's suitability for 
repeated assembly and disassembly similar to the example of valve 
replacement when all parts of the end fitting are reused.
    Another type of end fitting is the push-to-connect fitting, which 
when used in an assembly, the end of the tubing is simply pushed into 
the fitting. To remove the tubing for repair purposes, a ring on the 
fitting around the outside of the tubing is raised to release the 
tubing, which can then be pulled out of the fitting. All information 
the agency has collected on this type of fitting indicates that the 
tubing may or may not be damaged upon removal from the fitting, 
depending on such factors as how much air pressure and pulling force 
the assembly has been subjected to during its use. If the tubing is 
damaged, a small section cut off for subsequent reassembly if there is 
a sufficient slack available in the assembly. If there is not enough 
tubing length to cut the end off for reassembly, then a new section of 
tubing will need to be installed. If the O-ring in the push-to-connect 
fitting is also damaged, it may be serviced or the entire fitting will 
need to be replaced. This would have to be detected by the technician 
checking for leakage after reassembly.
    NHTSA proposes that the serviceability test be included in Standard 
No. 106 for those fittings that use a threaded retaining nut. This will 
ensure that the fittings can be separated and reused during servicing 
of brake system components with minimal likelihood of leakage upon 
reassembly. NTHSA does not believe the serviceability test could be 
consistently applied to push-to-connect fittings and therefore does not 
propose to include them in this test.
7. Fitting Compatibility Test
    SAE J1131 specifies that test specimens be prepared according to 
the fitting manufacturer's recommendations, with 12 inches of free hose 
length. The assembly is filled with hydraulic fluid at atmospheric 
pressure and conditioned at 200 degrees F for 24 hours. The pressure is 
then increased to 450 psi for 5 minutes after which time the pressure 
is reduced to atmospheric levels and the assembly is cooled to 75 
degrees F. Following this, the tubing assembly is cooled to minus 40 
degrees F with the fluid at atmospheric pressure for 24 hours after 
which time the pressure is increased to 450 psi for 5 minutes. The 
tubing must not rupture or disconnect from the fittings. Standard No. 
106 does not have a corresponding set of test procedures/performance 
requirements. Accordingly, NHTSA proposes to incorporate the fitting 
compatibility test and performance requirements from SAE J1131 into 
FMVSS No. 106.
8. Constriction
    FMVSS No. 106 requires that each air brake hose assembly shall be 
not less than 66 percent of the nominal ID of the hose, except for 
those portions of end fittings that do not contain hose. SAE J1131 does 
not contain a corresponding requirement. As discussed in greater

[[Page 26405]]

detail above, NHTSA is proposing to require that all portions of air 
brake assemblies, including those portions of end fittings that do not 
contain hose, meet this requirement. NHTSA proposes to apply the same 
66 percent of nominal ID constriction requirement to plastic air brake 
tubing assemblies. The agency proposes to apply this requirement based 
on the tubing's nominal inside diameter even though, as noted above, 
NHTSA is proposing that other requirements relating to air brake tubing 
be expressed in terms of the tubing's nominal outside diameter.
9. End Fitting Dimensional Requirements
    FMVSS No. 106 does not presently contain end fitting dimensional 
requirements. The petitioners, however, requested incorporation of the 
requirements of FMCSR Sec.  393.46, which references two SAE standards 
containing such requirements. FMCSR Sec.  393.46 provides that splices 
in tubing installed on a vehicle after March 7, 1989, must use fittings 
that meet the requirements of SAE J512, Automotive Tube Fittings Rev. 
October 1980 (SAE J512) or, for air brake systems, SAE J246, Spherical 
and Flanged Sleeve (Compression) Tube Fittings Rev. March 1981 (SAE 
J246).
    SAE J512 provides general and dimensional specifications for the 
various types of tube fittings intended for general application in the 
automotive, appliance, and allied fields, and includes the following 
categories of fittings: flare type fittings, inverted flare type 
fittings, and tapered sleeve compression type fittings intended for use 
with annealed copper alloy tubing. SAE J512 states that the spherical 
sleeve compression fitting components in SAE J246 are not to be 
intermixed with tapered sleeve compression type fitting components in 
SAE J512. The dimensions of single and double 45 degree flares on 
tubing used in conjunction with flared and inverted flared fittings in 
SAE J512 are provided in a different SAE standard, SAE J533.
    The application of SAE J512 fittings in automotive braking systems 
as used in the U.S. is believed to be most commonly associated with 
inverted double flare hydraulic brake tubing connections, and also for 
metal tubing that may be used for connecting vacuum booster lines to 
engine manifolds. NHTSA does not believe that copper tubing is widely 
used in vehicle braking applications anymore. The agency also does not 
believe that SAE J512 fittings would be appropriate for use with 
plastic tubing.
    Both SAE J246 and SAE J512 include dimensional requirements for 
fitting length, concentricity, pipe threads, wrench hexes, ferrule 
seats, tube support sleeves in the case of plastic tubing fittings, and 
material properties of brass stock used in fittings and stainless steel 
stock used in plastic tubing support sleeves. The standards also permit 
steel to be used if requested by the purchaser.
    As already noted above, FMVSS No. 106 does not include any 
dimensional or material properties specifications for fittings used 
with brake hose or tubing. NHTSA does not agree with the petitioners 
that the substantive dimensional and material requirements of SAE J246 
and SAE J512 are needed in FMVSS No. 106 for a number of reasons. 
First, the agency tentatively concludes that fittings that have 
demonstrated their compatibility with plastic air brake tubing through 
the testing required by SAE J1131. Second, NHTSA does not favor 
incorporating the SAE requirements because neither SAE J246 nor SAE 
J512 provides fitting standards for metric sized plastic tubing. Third, 
although FMVSS No. 106 does not provide any dimensional specifications 
for any types of fittings used with other types of brake hose or 
tubing, the agency is not aware of any field problems associated with 
these brake products. Fourth, even if FMVSS were to incorporate the 
dimensional specifications from the SAE standards, at least one of 
those standards, SAE J246, explicitly states that the standard is not 
intended to restrict or preclude other designs of a tube fitting for 
use with SAE J844 air brake tubing.
    NHTSA tentatively concludes that the automotive industry generally 
standardizes, on a voluntary basis, such fittings for compatibility and 
repair purposes, and has no reason to believe that this will not 
continue to be the case for plastic air brake tubing fittings. Standard 
No. 106 currently permits specialized fittings as long as they can meet 
the specified performance requirements. In a November 13, 1973, final 
rule (38 FR 31302, Docket No. 1-5; Notice 8), NHTSA declined to adopt 
any specific standard for end fittings. For the reasons outlined above, 
NHTSA does not propose to include any dimensional or material 
properties specifications for end fittings at this time.
10. End Fitting Corrosion Resistance
    SAE J246 and SAE J512 specify that the external surfaces and 
threads of carbon steel fittings be subjected to a 72 hour salt spray 
test per ASTM B117, with no appearance of red rust permitted except 
for: Internal portions of fittings; edges such as hex points, 
serrations, or thread crests where there may be mechanical deformation 
of the plating or coating of mass-produced parts or shipping effects; 
areas where the plating or coating is subjected to mechanical 
deformation due to crimping, flaring, bending, or other post plate 
metal forming operations; or areas where the parts are suspended or 
affixed in the test chamber where condensate can accumulate. Both 
standards specify that after January 1, 1997, no parts shall be cadmium 
plated due to environmental concerns relating to that process.
    FMVSS No. 106 specifies that the fittings as installed on a brake 
hose assembly be subjected to a 24-hour salt spray test, the same test 
that is specified for hydraulic brake hose, as detailed above. The end 
fittings must 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. Standard No. 106 specifies 
that all fittings meet the corrosion test, and does not provide 
different specifications based on the end fitting's composition (steel, 
stainless steel, or brass).
    The duration of the salt spray test is longer in the SAE standards 
than in FMVSS No. 106 (72 hours versus 24 hours), but the specified 
corrosion performance is more rigorous in FMVSS No. 106. The SAE 
standards specify testing of fittings without any hose attached, while 
FMVSS No. 106 specifies that the fittings be mounted to a hose for 
testing. NHTSA tentatively concludes 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. Accordingly, the agency does not propose to change Standard 
No. 106's corrosion resistance requirements at this time. Nevertheless, 
NHTSA welcomes comments on the suitability and need to increase the 
duration of the salt spray test from the current 24 hours to the 72 
hours specified in the SAE standards.
    The table below summarizes the differences between the plastic air 
brake tubing assembly and end fitting performance requirements/test 
procedures of FMVSS No. 106 and SAE J1131 and indicates which 
requirements/procedures NHTSA proposes incorporating into the standard.

[[Page 26406]]



    Table 5.--Comparison of Plastic Air Brake Tubing Assembly and End
   Fitting Requirements/Procedures in FMVSS No. 106 and SAE J1131, SAE
                           J246, and SAE J512
------------------------------------------------------------------------
                                    Existing FMVSS
    Requirement/Procedure              No. 106              SAE J1131
------------------------------------------------------------------------
                   Fittings for Nylon Air Brake Tubing
``x'' indicates requirements/procedures proposed to be included in FMVSS
   No. 106. A new section would be added for the performance of these
  fittings. Existing FMVSS No. 106 requirements/procedures for fittings
                            would also apply.
------------------------------------------------------------------------
Tensile Strength............   x   Same as for air  ...  No tensile test
                                    brake hose            at ambient
                                    assemblies.           conditions.
Hot Tensile Strength........  ...  Only at ambient   x   Immersion in
                                    temperature,          boiling water
                                    higher                followed by
                                    strength              pull test.
                                    specifications.
Conditioned Pull Test.......  ...  Only at ambient   x   Four cold soak
                                    temperature,          cycles
                                    higher                followed by
                                    strength              boiling water,
                                    specifications.       then pull
                                                          test.
Vibration Leak Test.........  ...  None...........   x   Leakage
                                                          specification
                                                          after
                                                          vibration
                                                          conditioning.
Proof and Burst Test........  ...  Burst test,       x   No fitting
                                    does not              separation
                                    specify               during proof
                                    failure mode.         and burst
                                                          tests.
Serviceability Test.........  ...  None...........   x   Leakage
                                                          specifications
                                                          for flanged-
                                                          sleeve
                                                          fittings after
                                                          five assembly
                                                          cycles.
Fitting Compatibility Test..  ...  None...........   x   Pressure and
                                                          temperature
                                                          cycling to
                                                          evaluate
                                                          fitting
                                                          retention.
Constriction................   x   66 percent of    ...  None.
                                    nominal inside
                                    diameter.
End Fitting Dimensional        x   None...........  ...  Specified in
 Requirements.                                            SAE J246 and
                                                          SAE J512--
                                                          variations
                                                          permitted.
End Fitting Corrosion          x   Same as for      ...  Specified in
 Resistance.                        hydraulic             SAE J246 and
                                    brake hose end        SAE J512--
                                    fittings.             similar,
                                                          exemption for
                                                          brass
                                                          fittings.
------------------------------------------------------------------------

V. 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 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 is proposing to incorporate 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 proposes to incorporate 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 tentatively 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) tentatively 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 tentatively 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 how many hydraulic and vacuum 
brake hose assemblies would need to be modified to meet the proposed 
changes. 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 
proposed requirements. Likewise, the agency does not know the cost to 
modify the manufacturing processes of the brake

[[Page 26407]]

hose materials to comply with the proposed changes, 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 proposed regulations 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 proposed changes, at a 
cost of ten cents per hose, the total cost would be $1.6M Therefore, 
the agency estimates the cost of complying with the proposed changes to 
FMVSS No. 106 to be between zero and $1.6 M. 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 proposal would have any significant economic effects. 
Nevertheless, the agency welcomes comments on the cost of compliance 
with the proposed requirements.
    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 proposing to apply, 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 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.
    NHTSA has considered the effects of this rulemaking action under 
the Regulatory Flexibility Act. As explained above, NHTSA is proposing 
to incorporate 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 proposes to incorporate 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 $1.6M. Considering that the total number of 
hydraulic brake hose assemblies and vacuum brake hose/assemblies that 
would be subject to the proposed requirements is estimated to be 
approximately 80 million units annually, the agency estimates that the 
total annual effect of this proposed rule would be between zero and 
$1.6M. Accordingly, I hereby certify that it would 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 proposed rule would not have sufficient 
federalism implications to warrant consultation with State and local 
officials or the preparation of a federalism summary impact statement. 
The proposal would 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 proposed amendment would 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

[[Page 26408]]

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 proposed rule would not require any collections of 
information as 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 proposed changes that NHTSA is proposing are based on voluntary 
consensus standards adopted by the Society of Automotive Engineers. 
Accordingly, this proposed 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 proposed 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 estimated cost of 
complying with the proposed requirements is estimated to be between 
zero and $1.6M 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 on this NPRM.

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.

K. Comments

How Do I Prepare and Submit Comments?
    Your comments must be written and in English. To ensure that your 
comments are correctly filed in the Docket, please include the docket 
number of this document in your comments.
    Your comments must not be more than 15 pages long. (49 CFR 553.21). 
We established this limit to encourage you to write your primary 
comments in a concise fashion. However, you may attach necessary 
additional documents to your comments. There is no limit on the length 
of the attachments.
    Please submit two copies of your comments, including the 
attachments, to Docket Management at the address given above under 
ADDRESSES.
    You may also submit your comments to the docket electronically by 
logging onto the Dockets Management System Web site at http://dms.dot.gov. Click on ``Help & Information'' or ``Help/Info'' to obtain 
instructions for filing the document electronically.
How Can I Be Sure That My Comments Were Received?
    If you wish Docket Management to notify you upon its receipt of 
your comments, enclose a self-addressed, stamped postcard in the 
envelope containing your comments. Upon receiving your comments, Docket 
Management will return the postcard by mail.
How Do I Submit Confidential Business Information?
    If you wish to submit any information under a claim of 
confidentiality, you should submit three copies of your complete 
submission, including the information you claim to be confidential 
business information, to the Chief Counsel, NHTSA, at the address given 
above under FOR FURTHER INFORMATION CONTACT. In addition, you should 
submit two copies, from which you have deleted the claimed confidential 
business information, to Docket Management at the address given above 
under ADDRESSES. When you send a comment containing information claimed 
to be confidential business information, you should include a cover 
letter setting forth the information specified in our confidential 
business information regulation. (49 CFR part 512)
Will the Agency Consider Late Comments?
    We will consider all comments that Docket Management receives 
before the close of business on the comment closing date indicated 
above under DATES. To the extent possible, we will also consider 
comments that Docket Management receives after that date. If Docket 
Management receives a comment too late for us to consider it in 
developing a final rule (assuming that one is issued), we will consider 
that comment as an informal suggestion for future rulemaking action.

[[Page 26409]]

How Can I Read the Comments Submitted by Other People?
    You may read the comments received by Docket Management at the 
address given above under ADDRESSES. The hours of the Docket are 
indicated above in the same location.
    You may also see the comments on the Internet. To read the comments 
on the Internet, take the following steps:
    1. Go to the Docket Management System (DMS) Web page of the 
Department of Transportation (http://dms.dot.gov/)
    2. On that page, click on ``search.''
    3. On the next page (http://dms.dot.gov/search/), type in the four-
digit docket number shown at the beginning of this document. Example: 
If the docket number were ``NHTSA-1998-1234'', you would type ``1234''. 
After typing the docket number, click on ``search.''
    4. On the next page, which contains docket summary information for 
the docket you selected, click on the desired comments. You may 
download the comments. Although the comments are imaged documents, 
instead of word processing documents, the ``pdf'' versions of the 
documents are word searchable.
    Please note that even after the comment closing date, we will 
continue to file relevant information in the Docket as it becomes 
available. Further, some people may submit late comments. Accordingly, 
we recommend that you periodically check the Docket for new material.

List of Subjects in 49 CFR Part 571

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

    In consideration of the foregoing, NHTSA proposes to amend 49 CFR 
part 571 as follows:

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

    1. The authority for part 571 would continue to read as follows:

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

    2. Section 571.106 would be amended by:
    a. Adding a new definition to paragraph S4,
    b. Revising paragraph (b) of S5.2.2,
    c. Revising paragraph (b) of S5.2.4,
    d. Revising paragraphs S5.3 through S5.3.5,
    e. Revising paragraphs S5.3.9 and S5.3.11,
    f. Adding paragraphs S5.3.12 and S5.3.13,
    g. Revising paragraph (c) of S6.2,
    h. Revising paragraphs S6.4 and S6.4.2,
    i. Revising paragraph (b) of S6.8.2,
    j. Redesignating paragraphs S6.9, S6.9.1, S6.9.2, and S6.9.3 as 
paragraphs S6.11, S6.11.1, S6.11.2, and S6.11.3 and revising 
redesignated paragraph S6.11 and paragraph (c) of redesignated S6.11.3,
    k. Adding paragraphs S6.9 through S6.9.2,
    l. Adding paragraphs S6.10 through S6.10.2,
    m. Adding paragraph S6.12,
    n. Revising paragraphs (b), (d), and (e) of S7.2.1,
    o. Revising Table III,
    p. Revising paragraphs (b) and (d) of S7.2.2,
    q. Revising paragraphs S7.3 and S7.3.1,
    r. Revising paragraph S7.3.3,
    s. Revising Table IV,
    t. Revising paragraphs S7.3.6 through S7.3.11,
    u. Adding paragraph S7.3.14,
    v. Revising paragraphs (c) and (d) of S8.2,
    w. Revising paragraph (b) of S8.3.2,
    x. Revising the heading of paragraph S8.6,
    y. Revising paragraph S8.7,
    z. Adding paragraphs S8.7.1 and S8.7.2,
    aa. Revising paragraph S8.8,
    bb. Revising paragraph S8.9, introductory text,
    cc. Adding paragraphs S8.13 through S8.15,
    dd. Revising paragraphs S9.2 through S9.2.3,
    ee. Revising paragraphs S9.2.7 and S9.2.8,
    ff. Removing paragraph S9.2.9,
    gg. Redesignating paragraphs S9.2.10 and S9.2.11 as paragraphs 
S9.2.9 and S9.2.10,
    hh. Revising paragraphs S10.1 and S10.2,
    ii. Revising paragraphs S10.6(a) and S10.7,
    jj. Redesignating Figure 3 as Figure 6,
    kk. Removing paragraph S10.8,
    ll. Redesignating paragraphs S10.9, S10.9.1, S10.9.2, and S10.10 as 
paragraphs S10.8, S10.8.1, S10.8.2, and S10.9,
    mm. Revising paragraph (b) of newly redesignated paragraph S10.8.2,
    nn. Redesignating Figure 4 as Figure 7 and adding it at the end of 
paragraph S10.8.2(b),
    oo. Adding Figure 4,
    pp. Adding Figure 5,
    qq. Adding Figure 8,
    rr. Adding Figure 9,
    ss. Adding paragraph S10.10,
    tt. Redesignating paragraphs S11, S11.1, S11.2, and S11.3 as 
paragraphs S13, S13.1, S13.2, and S13.3,
    uu. Adding paragraphs S11 through S11.3.24,
    vv. Adding paragraphs S12 through S12.27,
    ww. Revising newly redesignated paragraphs S13 and S13.2, and
    xx. Adding paragraph S13.4.
    The additions and revisions to Sec.  571.106 would 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. S.W., Washington, DC 20590. The marking 
may consist of a designation other than block capital letters required 
by S5.2.2.
* * * * *
    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. S.W., Washington, DC 20590. The 
designation may consist of block capital letters, numerals, or a 
symbol.
* * * * *
    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.
    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

[[Page 26410]]

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 and 1,500 psi shall not 
exceed the values specified in Table I (S6.1). The hydraulic brake hose 
assembly shall then withstand water pressure of 4,000 psi for 2 minutes 
without rupture, and 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 \3/16\ inch, 4 mm, or larger diameter hose (S6.2).
* * * * *
    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).
    S5.3.5 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).
* * * * *
    S5.3.9 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 [deg]F for 70 hours while filled with SAE RM-
66-05 Compatibility Fluid, as described in Appendix B of SAE Standard 
J1703 JAN 1995, ``Motor Vehicle Brake Fluid.'' 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).
* * * * *
    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 [deg]F 
without leakage;
    (b) shall not leak 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.
* * * * *
    S6.2 Burst strength test. (a) * * *
    (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 
hose of \3/16\, 4 mm, or larger diameter, or 7,000 psi for a 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) Standard Practices for Force Verification of Testing 
Machines, Designation E4-99, and provided with a recording device to 
give the total pull in pounds.
* * * * *
    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.
* * * * *
    S6.8.2 Exposure to ozone. (a) * * *
    (b) Immediately thereafter, condition the hose on the cylinder for 
70 hours in an exposure chamber having an ambient air temperature of 
104 [deg]F 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.

Figure 3. Dynamic Ozone Test Apparatus

[[Page 26411]]

[GRAPHIC] [TIFF OMITTED] TP15MY03.018

    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 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 is 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 
[deg]F within 30 minutes, and that can maintain a constant 295 [deg]F 
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-66-05 Compatibility Fluid, as 
described in Appendix B of SAE Standard J1703 JAN 1995, 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 
[deg]F 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.
    S6.11 End fitting corrosion test. Utilize the apparatus described 
in ASTM B117-97, ``Standard Practice for Operating Salt Spray (Fog) 
Apparatus''.
* * * * *
    S6.11.3 Operation. * * *
* * * * *
    (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 [deg]F and then drying immediately.
* * * * *
    S6.12 Constriction Test.
    (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 three 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 three inches from the point at which 
the hose terminates in the end fitting and then tested from the cut 
end.

[[Page 26412]]

    (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, this 
constitutes failure of the constriction test.
    (e) Release the plug gauge. Within three 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.

Figure 4. Constriction Test Plug Gauge
[GRAPHIC] [TIFF OMITTED] TP15MY03.019

    S7. Requirements--Air brake hose, brake hose assemblies, and brake 
hose end fittings.
* * * * *
    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. The 
designation may consist of block capital letters, numerals, or a 
symbol.
* * * * *
    (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 letter ``A'' shall indicate intended use in air brake 
systems. In the case of a hose intended for use in a reusable assembly, 
``AI'' or ``AII'' shall indicate Type I or Type II dimensional 
characteristics of the hose as described in Table III. A hose that is 
intended to be used with more than one type of end fitting may be 
labeled with multiple designations. (Examples: AI-AII, AI & AII.)

                          Table III.--Air Brake Hose Dimensions for Reusable Assemblies
----------------------------------------------------------------------------------------------------------------
                                                    Inside    Type I outside diameter,       Type II outside
                                                   diameter            inches               diameter, inches
                  Size, inches                    tolerance, ---------------------------------------------------
                                                    inches      Minimum      Maximum      Minimum      Maximum
----------------------------------------------------------------------------------------------------------------
\3/16\.........................................       +0.026        0.472        0.510        0.500        0.539
                                                      -0.000
\1/4\..........................................       +0.031        0.535        0.573        0.562        0.602
                                                      -0.000
\5/16\.........................................       +0.031        0.598        0.636        0.656        0.695
                                                      -0.000
\3/8\..........................................     +/-0.023        0.719        0.781        0.719        0.781
\7/16\.........................................     +/-0.031        0.781        0.843        0.781        0.843
\13/32\........................................       +0.031        0.714        0.760        0.742        0.789
                                                      -0.000
\1/2\..........................................       +0.039        0.808        0.854        0.898        0.945
                                                      -0.000
\5/8\..........................................       +0.042        0.933        0.979        1.054        1.101
                                                      -0.000
\1/2\ special..................................     +/-0.031        0.844        0.906        0.844        0.906
----------------------------------------------------------------------------------------------------------------


[[Page 26413]]

    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. SW., Washington, 
DC 20590. The designation may consist of block capital letters, 
numerals, or a symbol.
* * * * *
    (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. (S8.15)
* * * * *
    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 [deg]F for 70 hours when bent around a 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 diameter, inches \1\.......   \1/8\   \3/16\    \1/4\   \5/16\    \3/8\   \13/32\  \7/16,\   \5/8\
                                                                                                 \1/2\
Nominal hose diameter, millimeters \1\..       3     4, 5        6        8   .......      10       12       16
Test cylinder radius for high                  1        1   1\1/2\   1\3/4\   1\3/4\   1\7/8\        2   2\1/2\
 temperature resistance test and             (25)     (25)     (38)     (44)     (44)     (48)     (51)     (64)
 adhesion test for wire reinforced hose,
 inches (mm)............................
Test cylinder radius for low temperature  1\1/2\        2   2\1/2\        3    3 (89)  3\1/2\        4   4\1/2\
 resistance test and ozone test, inches      (38)     (51)     (64)     (76)              (89)    (102)    (114) 
 (mm)...................................
----------------------------------------------------------------------------------------------------------------
\1\ These sizes are listed to provide test values for brake hose manufactured in these sizes. They do not
  represent conversions.

* * * * *
    S7.3.6 Length Change. An airbrake 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 Table 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 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 (S8.9).
    S7.3.11 Water absorption and tensile strength. After immersion in 
distilled water for 70 hours (S8.10), an air brake hose assembly 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 (S8.9).
* * * * *
    S7.3.14 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 [deg]F when bent around a test cylinder of the radius 
specified in Table IV for the size of hose tested (S8.14).
    S8. Test procedures--Air brake hose, brake hose assemblies, and 
brake hose end fittings.
* * * * *
    S8.2 Low temperature resistance test.
* * * * *
    (c) With the hose and cylinder at minus 40 [deg]F, 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 
[deg]F. and then cool in ASTM IRM 903 oil at room temperature for 30 to 
60 minutes.
* * * * *
    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

[[Page 26414]]

in the hose assembly from 150 to zero psi within 2 seconds.

Figure 5. Flex Test Apparatus
[GRAPHIC] [TIFF OMITTED] TP15MY03.020


                                                                                   Table Accompanying Figure 5
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                    Dimensions
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
  Free hose length 27 (1.6mm)     Hose I.D., in                               Position ``1''                                                          Position ``2''
                                      (mm)       -----------------------------------------------------------------------------------------------------------------------------------------------
                                                        ``A''             ``B''             ``C''            ``R'' a            ``A''             ``B''             ``C''            ``R'' a
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
10 in (254 mm)................  \3/16\ (4.8 );    3 in (76 mm)....  2.75 in (70 mm).  3.75 in (95 mm).  1.4 in (34 mm)..  3 in (76 mm)....  2.75 in (70 mm).  3.75 in (95 mm).  1.2 in 30 mm).
                                 \1/4\ (6.3).
11 in (279 mm)................  \5/16\ (7.9); \3/ 3 in (76 mm)....  3.5 in (8.9 mm).  \4/5\ in (114     1.7 in (43 mm)..  3 in (76 mm)....  3.5 in (89 mm)..  4.5 in (114 mm).  1.3 in (33 mm).
                                 8\ (9.7); \13/                                        mm).
                                 32\ (10.4).
14 in (355 mm)................  \7/16\ (11.2);    3 in (76 mm)....  4 in (102 mm)...  4 in (127 mm)...  2.2 in (56 mm)..  3 in (76 mm)....  4 in (102 mm)...  5 in (127 mm)...  1.8 in (46 mm).
                                 \1/2\ (12.7;
                                 (\5/8\ (16.0).
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
a This is an approximate average radius.

    8.7.2 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 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 S6.9 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 [deg]F 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 (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 1 
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 continues to be supplied through the orifice.
    S8.8 Corrosion resistance and burst strength test. (a) Conduct the 
test specified in S6.9 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) Standard Practices for Force Verification of Testing 
Machines, Designation E4-99, and provided with a recording device to 
register total pull in pounds.
* * * * *
    S8.13 Adhesion test for air brake hose reinforced by wire. (a) 
Place a steel ball with a diameter equal to 75 percent of the nominal 
inside diameter of the hose being tested inside of the hose. Plug one 
end of the hose. Attach the

[[Page 26415]]

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 test cylinder of the size specified in Table IV for 
the hose being 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 Ozone test. Conduct the test in S6.8 on an air brake hose 
assembly except use the test cylinder radius specified in Table IV for 
the size of hose tested.
    S8.15 Constriction test.
    (a) Utilize a plug gauge as shown in Figure 4. Diameter ``A'' shall 
be equal to 66 percent of the nominal inside diameter of the air brake 
hose being tested.
    (b) Air brake hose assemblies that are to be used for additional 
testing have constriction testing only at each end fitting. Other hose 
assemblies may be cut into three inch lengths to permit constriction 
testing of the entire assembly.
    (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, this 
constitutes failure of the constriction test.
    (e) Release the plug gauge. Within three 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.
    S9. Requirements--Vacuum brake hose, brake hose assemblies, and 
brake hose end fittings.
* * * * *
    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 [deg]F 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.
* * * * *
    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 8 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 S10.9, except that a wire-
reinforced hose need only return to 85 percent of its original outside 
diameter. In the case of 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. 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 [deg]F for a period of 96 hours. Remove the 
hose to room temperature and atmospheric pressure.
    (c) Within 5 minutes of completion of the test in (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 using vacuum brake hose with 
the cylinder radius specified in Table V for the size of hose tested. 
Visually inspect the exterior of the hose for cracks without 
magnification.
    (b) Remove the hose from the test cylinder, warm the hose at room 
temperature for 5 hours, and conduct the hydrostatic pressure test in 
10.1(e).
* * * * *
    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

[[Page 26416]]

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 D471-98e1 Standard Test Method 
for Rubber Property B Effect of Liquids.
    (b) Maintain reference fuel in the hose under atmospheric pressure 
at room temperature for 48 hours.
    (c) Remove fuel and determine that every inside diameter of any 
section of the brake hose is not less than 75 percent of the nominal 
inside diameter of the hose for heavy-duty hose and 70 percent of the 
nominal inside diameter of the hose for light-duty hose.
    (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.
* * * * *
    S10.8.2 * * *
* * * * *
    (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.
    (a) Utilize a plug gauge is shown in Figure 4. Diameter AA'' shall 
be equal to 75 percent of the nominal inside diameter of the vacuum 
brake hose being tested if it is heavy duty, or 70 percent of the 
nominal inside diameter of the vacuum brake hose being tested if it is 
light duty.
    (b) Vacuum brake hose assemblies that are to be used for additional 
testing have constriction testing only at each end fitting. Other hose 
assemblies may be cut into three 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) are cut 
three inches from the point at which the hose terminates in the end 
fitting and then tested from the cut end.
    (c) Hold the vacuum 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, this 
constitutes failure of the constriction test.
    (e) Release the plug gauge. Within three 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.
    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 brake hose end fittings or reusable 
brake hose end fittings. Plastic air brake tubing that is constructed 
of one layer of material shall be designated as Type A tubing and 
plastic air brake tubing that is constructed of two layers of material 
with a reinforcing braid between the layers shall be designated as Type 
B tubing. 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
           Type                   Nominal tubing OD        ---------------------------------------------------------------------------------------------
                                                               mm      inch      mm      inch      mm      inch      mm      inch       mm        inch
--------------------------------------------------------------------------------------------------------------------------------------------------------
A........................  \1/8\ inch.....................     3.25    0.128     3.10    0.122     2.01    0.079     0.58    0.023    +/-0.08   +/-0.003
A........................  \5/32\ inch....................     4.04    0.159     3.89    0.153     2.34    0.092     0.81    0.032    +/-0.08   +/-0.003
A........................  \3/16\ inch....................     4.83    0.190     4.67    0.184     2.97    0.117     0.89    0.035    +/-0.08   +/-0.003
A........................  \1/4\ inch.....................     6.43    0.253     6.27    0.247     4.32    0.170     1.02    0.040    +/-0.08   +/-0.003
A........................  \5/16\ inch....................     8.03    0.316     7.82    0.308     5.89    0.232     1.02    0.040    +/-0.10   +/-0.004
B........................  \3/8\ inch.....................     9.69    0.379     9.42    0.371     6.38    0.251     1.57    0.062    +/-0.10   +/-0.004
B........................  \1/2\ inch.....................    12.83    0.505    12.57    0.495     9.55    0.376     1.57    0.062    +/-0.10   +/-0.004
B........................  \5/8\ inch.....................    16.00    0.630    15.75    0.620    11.20    0.441     2.34    0.092    +/-0.13   +/-0.005
B........................  \3/4\ inch.....................    19.18    0.755    18.92    0.745    14.38    0.566     2.34    0.092    +/-0.13   +/-0.005
A........................  6 mm...........................     6.10    0.240     5.90    0.232     4.00    0.157     1.00    0.039    +/-0.10   +/-0.004
A........................  8 mm...........................     8.10    0.319     7.90    0.311     6.00    0.236     1.00    0.039    +/-0.10   +/-0.004
B........................  10 mm..........................    10.15    0.399     9.85    0.387     7.00    0.275     1.50    0.059    +/-0.15   +/-0.006
B........................  12 mm..........................    12.15    0.478    11.85    0.466     9.00    0.354     1.50    0.059    +/-0.15   +/-0.006
B........................  16 mm..........................    16.15    0.635    15.85    0.623    12.00    0.472     2.00    0.079    +/-0.15   +/-0.006
--------------------------------------------------------------------------------------------------------------------------------------------------------

    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. S.W., 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

[[Page 26417]]

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 of that component that the component conforms to all 
applicable motor vehicle safety standards.
    (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. 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. (See 
examples in S11.2.1(d).)
    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. S.W., 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 S11.3.24.
    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 [deg]F 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 Moisture absorption. Plastic air brake tubing shall not 
absorb moisture in a quantity of more than 2 percent by weight after 
conditioning in air at 230 [deg]F for 24 hours and then conditioning in 
a 100 percent relative humidity atmosphere at 75 [deg]F for 100 hours. 
(S12.5)
    S11.3.5 Burst strength. Plastic air brake tubing shall not rupture 
or burst when subjected to the burst strength pressure in Table VIII 
for the size of tubing being tested, when tested at an ambient 
temperature of 75 [deg]F. (S12.6)

                           Table VIII.--Plastic Air Brake Tubing Mechanical Properties
----------------------------------------------------------------------------------------------------------------
                                    Burst strength      Stiffness force       Bend radius        Tensile load
                                       pressure      -----------------------------------------------------------
    Type       Nominal tubing OD --------------------
                                     kPa       psi        N        lbf       mm      inches       N        lbf
----------------------------------------------------------------------------------------------------------------
A...........  \1/8\ inch........      6900      1000       4.4       1.0       9.4      0.37        67        15
A...........  \5/32\ inch.......      8300      1200       4.4       1.0      12.7      0.50       178        40
A...........  \3/16\ inch.......      8300      1200       4.4       1.0      19.1      0.75       178        40
A...........  \1/4\ inch........      8300      1200       8.9       2.0      25.4      1.00       222        50
A...........  \5/16\ inch.......      6900      1000      27.0       6.0      31.8      1.25       334        75
B...........  \3/8\ inch........      9700      1400      36.0       8.0      38.1      1.50      6671        50
B...........  \1/2\ inch........      6600       950      89.0      20.0      50.8      2.00       890       200
B...........  \5/8\ inch........      6200       900     222.0      50.0      63.5      2.50      1446       325
B...........  \3/4\ inch........      5500       800     356.0      80.0      76.2      3.00      1557       350
A...........  6 mm..............      7600      1100       9.0       2.0      20.0      0.75       222        50
A...........  8 mm..............      6200       900      27.0       6.0      32.0      1.25       334        75
B...........  10 mm.............      8200      1200      36.0       8.0      38.0      1.50       667       150
B...........  12 mm.............      6900      1000      90.0      20.0      45.0      1.75       890       200
B...........  16 mm.............      6000       875     225.0      50.0      70.0      2.75      1446       325
----------------------------------------------------------------------------------------------------------------

    S11.3.6 Ultraviolet light 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 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 [deg]F for 24 hours, and then 
conditioning in air at minus 40 [deg]F for four hours, and then bending 
the tubing 180 degrees around a test cylinder having a radius equal to

[[Page 26418]]

six times the nominal outside diameter of the tubing. (S12.8)
    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 [deg]F for 72 hours while bent 180 
degrees around a cylinder having a radius of two times the nominal 
outside diameter of the tubing; 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 [deg]F 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 [deg]F for 24 hours, then conditioned in air 
at minus 40 [deg]F 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 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 boiling water for two hours, then conditioned in air at 
minus 40 [deg]F 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 of two times the 
nominal outside diameter of the tubing. (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 of 
two times the nominal outside diameter of the tubing (S12.14)
    S11.3.14 High temperature conditioning and stiffness. Plastic air 
brake tubing shall require not more than the stiffness force specified 
in Table VIII to deflect 2 inches, when tested using the apparatus in 
Figure 9, after conditioning in air at 230 [deg]F for 24 hours with the 
tubing supported in a straight position. (S12.15)
    S11.3.15 High temperature conditioning and adhesion. Type B plastic 
air brake tubing shall have a tensile strength of 25 pounds per linear 
inch, measured at the interface of the inner and outer layers, after 
conditioning as specified in S11.3.8(a) through (c). (S12.16)
    S11.3.16 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 bend radius specified in Table VIII 
and conditioned in air at 200 [deg]F for 24 hours. (S12.17)
    S11.3.17 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 [deg]F. (S12.18)
    S11.3.18 Oil 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 ASTM IRM 903 oil at 212 [deg]F for 70 hours. 
(S12.19)
    S11.3.19 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 or less or 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 or 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. (S12.20)
    S11.3.20 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 tensile load in Table VIII 
without separation from its end fittings, with one end of the assembly 
conditioned in boiling water for 5 minutes. (S12.21)
    S11.3.21 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 tensile strength 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 [deg]F 
for thirty minutes, normalizing at room temperature, conditioning in 
boiling water for 15 minutes, and normalizing at room temperature. 
(S12.22)
    S11.3.22 Vibration resistance. A plastic air brake tubing assembly 
with an internal air pressure of 120 psi shall not leak more than 50 
cm3 per minute at a temperature of minus 40 [deg]F and 25 
cm3 per minute at a temperature of 75 [deg]F, 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 [deg]F 
and 220 [deg]F during the test. (S12.23)
    S11.3.23 End fitting retention. The end fittings of a plastic air 
brake tubing assembly shall not separate from the tubing or leak when 
the assembly is filled with hydraulic fluid and pressurized to the 
burst strength pressure in Table VIII. (S12.24)
    S11.3.24 Thermal conditioning and end fitting retention. The end 
fittings of a plastic air brake tubing assembly shall not separate from 
the tubing or leak when filled with hydraulic fluid and:
    (a) conditioned in air at 200 [deg]F for 24 hours with atmospheric 
pressure inside the tubing assembly, and;
    (b) maintaining an air temperature of 200 [deg]F and increasing the 
pressure inside the tubing assembly to 450 psi, and holding this 
pressure for five minutes, and;
    (c) reducing the internal tubing assembly pressure to atmospheric 
and permitting the tubing assembly to cool at 75 NF for 1 hour, and;
    (d) conditioning the tubing assembly in air at minus 40 [deg]F for 
24 hours with atmospheric pressure inside the tubing assembly, and;
    (e) maintaining an air temperature of minus 40 [deg]F and 
increasing the pressure inside the tubing assembly to 450 psi,

[[Page 26419]]

and holding this pressure for five minutes. (S12.25)
    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. (S12.26)
    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 gauge blocks, 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.
    (a) Utilize a plug gauge as shown in Figure 4. Diameter ``A'' shall 
be equal to 66 percent of the nominal inside diameter of the plastic 
air brake tubing being tested.
    (b) Tubing assemblies that are to be used for additional testing 
shall have constriction testing only at each end fitting. Other tubing 
assemblies may be cut into three inch lengths to permit constriction 
testing of the entire assembly.
    (c) Hold the tubing in a straight position and vertical 
orientation.
    (d) Place the spherical end of the plug gauge just inside the 
tubing. If the spherical end will not enter the tubing or end fitting 
using no more force than gravity acting on the plug gauge, this 
constitutes failure of the constriction test.
    (e) Release the plug gauge. Within three 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 tubing up to the 
handle of the gauge within three seconds, this constitutes failure of 
the constriction test.
    S12.3 High temperature conditioning and dimensional stability test.
    (a) Condition the tubing at 230 [deg]F 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 pot constructed of a non-reactive material and fill 
with distilled water.
    (b) Cut the tubing to a length that will fit into the pot without 
touching any surface of the pot. 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 pot. 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 Moisture absorption test.
    (a) Prepare a sample of tubing twelve inches in length.
    (b) Condition the tubing at 230 [deg]F for 24 hours in an air oven. 
Remove the tubing from the oven and within 30 seconds, weigh it to 
establish the initial weight. The weight shall be measured with a 
resolution of 0.01g; if the scale has a higher resolution, then values 
of 0.005g and above shall be rounded to the nearest 0.01g and values 
below 0.005g 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 
[deg]F.
    (d) Remove the tubing from the chamber 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 0.01g as in (b) above.
    (e) Calculate percentage of moisture absorption as follows:

[Conditioned Weight-Initial Weight] / [Initial Weight] x 100

    S12.6 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) Connect one end of the tubing assembly to a source of air 
pressure and plug the other end.
    (c) Increase the pressure inside the tubing assembly at a constant 
rate to the burst strength pressure for the size of tubing being tested 
as specified in Table VIII within a period of 5 seconds.
    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 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.
    (c) Preparation.
    (i) 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.
    (ii) 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 and the longitudinal axis of 
the tubing is parallel to the fluorescent bulb. (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 is each 96 hours instead of weekly.) The distance from the 
light bulb to the tubing is approximately 2 inches. Set the UV 
irradiance to 0.85 W/m\2\ @ 340 nm and maintain this level during the 
testing. Maintain a temperature inside the test chamber of 113 [deg]F, 
and use only atmospheric humidity. Expose the tubing at this UV 
irradiance level for 300 hours continuously. Remove the tubing from the 
test chamber.
    (iii) Place the tubing inside the impact test apparatus, and drop 
the impacter onto the tubing from a height of 12 inches.
    (iv) 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 S12.6 using 80 percent 
of the burst strength pressure for the size of tubing being tested as 
specified in Table VIII.

Figure 8. Impact Test Apparatus

[[Page 26420]]

[GRAPHIC] [TIFF OMITTED] TP15MY03.021


                       Table Accompanying Figure 8
------------------------------------------------------------------------
                                                 Hole DIA D   Hole DIA D
               Nominal tube O.D.                    (mm)         (in)
------------------------------------------------------------------------
\1/8\ in......................................         3.96        0.156
\5/32\ in.....................................         4.75        0.187
\3/16\ in.....................................         5.54        0.218
\1/4\ in......................................         7.14        0.281
\5/16\ in.....................................         8.71        0.343
\3/8\ in......................................        10.31        0.406
\1/2\ in......................................        13.49        0.531
\5/8\ in......................................        16.66        0.656
\3/4\ in......................................        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 [deg]F 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 [deg]F for four hours.
    (d) With the tubing and test cylinder at minus 40 [deg]F, 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 of two times the nominal 
outside diameter of the tubing.
    (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 [deg]F 
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 mandrel, at the same 
point

[[Page 26421]]

but in the opposite direction of the bending in (b) above, at a steady 
rate in a period of 4 to 8 seconds.
    (f) Conduct the burst strength test in S12.6 using 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 [deg]F for 72 hours. Remove the tubing and allow to 
cool at room temperature for 30 minutes. Conduct the burst strength 
test in S12.6 using 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 [deg]F 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 [deg]F for 4 hours.
    (d) With the tubing and impact test apparatus at minus 40 [deg]F, 
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 S12.6 using 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).
    (c) Condition the tubing and the impact test apparatus in an 
environmental chamber at minus 40 [deg]F for 4 hours.
    (d) With the tubing and impact test apparatus at minus 40 [deg]F, 
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 S12.6 using 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 of two times the nominal 
outside diameter of the tubing. The cylinder is constructed of a non-
reactive material or coated to prevent chemical reaction with zinc 
chloride.
    (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 of two times the nominal 
outside diameter of the tubing. 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.
    (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 stiffness.
    (a) Apparatus. Use a flexibility test device shown in Figure 9 with 
a spring scale or force transducer to measure the force applied to the 
tubing during bending.
    (b) Prepare an 11-inch long length of tubing. Insert a metal rod 12 
inches long of suitable diameter to provide a slip fit inside the 
tubing, and insert it in the tubing to hold it in a straight position 
within \1/8\ inch of true straightness.
    (c) Condition the tubing in an air oven at 230 [deg]F for 24 hours. 
Remove the tubing and allow to cool at room temperature for two hours.
    (d) Remove the metal rod from the tubing and place the tubing in 
the flexibility test device, with the tubing centered on the device and 
clearance removed between tubing and the pins and cylinder of the test 
device.. Mark the location of each end of the tubing. Pull on the 
device until both ends of the tubing have deflected 2 inches from the 
original position. Record the force applied to the device and verify 
that it does not exceed the stiffness force in Table VII for the size 
of tubing being tested.

Figure 9. Stiffness Test Apparatus

[[Page 26422]]

[GRAPHIC] [TIFF OMITTED] TP15MY03.022

    S12.16 High temperature conditioning and adhesion test.
    S12.16.1 Apparatus. A tension testing machine that conforms to the 
requirements of American Society for Testing and Materials (ASTM) 
Standard Practices for Force Verification of Testing Machines, 
Designation E4-99. The machine shall have one movable and one fixed jaw 
suitable for clamping small sections of plastic air brake tubing 
material. The machine produces a chart or has a recording device 
providing displacement as one coordinate and tensile force as the 
other.
    S12.16.2 Preparation.
    (a) Subject the tubing to the bending and temperature conditioning 
tests specified in S12.9 (a) through (e).
    (b) Cut a test specimen of 1 inch in length from a section of 
tubing that was subjected to bending in (a).
    (c) Cut the specimen longitudinally along its entire length so that 
one wall of the tubing is completely cut through. Along one edge of the 
specimen resulting from this cut, use a sharp knife and cut the tubing 
at the interface of the inner and outer layers until two flaps of 
material are created that are large enough to be clamped in the tension 
testing machine. One flap consists of material from the inner layer and 
one flap consists of material from the outer layer.
    (d) Mount the specimen in the tension testing machine by clamping 
one flap in each jaw. Apply a tensile force of 25 pounds to the flaps 
of the specimen in a period of 5 seconds and maintain this force for 
the duration of the test. The specimen is permitted to separate a small 
amount until the inner and outer layer interface becomes fully engaged 
and a continuous line of reinforcing braid is not present at the layer 
interface. The layers of the specimen shall not separate thereafter.
    S12.17 High temperature conditioning and collapse resistance test.
    (a) Apparatus. A holding device with two vertical pins, the 
distance between which can be adjusted by moving one or both pins. The 
bottoms of the pins are attached to the device and remain in a 
horizontal plane. The diameter of the pins is approximately the same as 
the inside diameter of the size of tubing to be tested, and is 1 inch 
in length.

[[Page 26423]]

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

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

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

    (ii) 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 minor diameter as the initial outside 
diameter.
    (iii) Install the tubing completely over the pins of the holding 
device so that the tubing is bent 180 degrees. Adjust the distance 
between the pins until the bent radius of the tubing is approximately 
equal to the bend radius for the size of tubing being tested from Table 
VIII.
    (iv) Condition the holding device and tubing in an air oven at 230 
[deg]F for 24 hours. Remove the holding device and tubing and allow to 
cool at room temperature for thirty minutes.
    (v) With the tubing still mounted to the holding device, measure 
the 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

    S12.18 Ozone resistance test. Conduct the test specified in S6.8 
using plastic air brake tubing.
    S12.19 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 [deg]F for 
70 hours. Remove and allow to cool at room temperature for 30 minutes. 
Wipe any excess oil from the tubing assembly.
    (c) Connect one end of the tubing assembly to a source of air 
pressure and plug the other end.
    (d) Increase the pressure inside the tubing assembly at a constant 
rate to 80 percent of the burst strength pressure for the size of 
tubing being tested as specified in Table VIII within a period of 5 
seconds.
    S12.20 Tensile strength test. Conduct the test specified in S6.9 
using a plastic air brake tubing assembly or an assembly prepared from 
a 12 inch length of tubing with the end fittings according to the end 
fitting manufacturer's instructions.
    S12.21 Boiling water conditioning and tensile strength.
    (a) Apparatus. Use the tension testing machine specified in S8.9. 
Equip the lower attachment point of the machine with a heated, open-top 
container. The container acts as the lower attachment point for a brake 
tubing assembly, or it may have a hole in the bottom for the lower 
attachment point of the machine to pass through the container provided 
that the hole is sealed water-tight to the machine.
    (b) Preparation. Prepare an air brake tubing assembly with a free 
length of six inches in accordance with the end fitting manufacturer's 
instructions. 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. Install the tubing assembly on the tension 
testing machine with the lower fitting plugged to prevent water from 
entering the tubing. Fill the container with distilled water so that 4 
inches of exposed tubing is submerged. Heat the water until it boils. 
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 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.
    S12.22 Thermal conditioning and tensile strength.
    (a) Apparatus. Use the tension testing machine specified in S8.9.
    (b) Preparation. Prepare an air brake tubing assembly with a free 
length of six inches in accordance with the end fitting manufacturer's 
instructions. 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. Subject the tubing assembly to four complete 
cycles of the following sequence:
    (i) Condition the tubing assembly in an environmental chamber at 
minus 40 [deg]F for 30 minutes. Remove from the chamber and allow to 
warm at room temperature for 30 minutes.
    (ii) 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 1 inch per minute 
travel of the moving head until either the 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.
    S12.23 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:
    (i) 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.
    (i) The distance between the attachment points is adjustable to 
compensate for varying lengths of brake tubing assemblies.
    (ii) The actuating mechanism for the movable attachment point is 
balanced to prevent introduction of machine vibration into the brake 
tubing assembly.
    (iii) 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.
    (iv) The machine is constructed so that an air brake tubing 
assembly mounted on it can be conditioned in an environmental test 
chamber.
    (b) Preparation. (i) Prepare an air brake tubing assembly with a 
free length of eighteen inches in accordance with the end fitting 
manufacturer's instructions. 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.
    (ii) 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.
    (iii) With the tubing assembly inside the environmental chamber, 
supply compressed air to the tubing assembly at a pressure of 120 psig 
and maintain this supply pressure for the duration of the test. Set the 
temperature of the environmental chamber to 220 [deg]F and initiate 
cycling of the movable attachment point. After 250,000 cycles,

[[Page 26424]]

set the temperature of the environmental chamber to minus 40 [deg]F. 
After 500,000 cycles, set the temperature of the environmental chamber 
to 220 [deg]F. After 750,000 cycles, set the temperature of the 
environmental chamber to minus 40 [deg]F. 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 cm3 per 
minute this constitutes failure of the test. Stop the cycling at 
1,000,000 cycles and set the environmental chamber temperature to 75 
[deg]F, while air pressure is still supplied to the air brake tubing 
assembly. After 1 hour, measure the compressed air flow rate supplied 
to the air brake tubing assembly and if the rate exceeds 25 
cm3 per minute this constitutes failure of the test.
    (iv) For end fittings that use a threaded retaining nut, apply 20 
percent of the original tightening torque as measured in S11.3.22, in 
the direction of tightening. If the retention nut visibly moves, this 
constitutes a failure of the test.
    S12.24 End fitting retention test.
    (a) Apparatus. A source of hydraulic pressure that includes a 
pressure gauge or monitoring system, and uses a petroleum-based 
hydraulic fluid with a pour point of less than minus 40 [deg]F.
    (b) Preparation. Utilize an air brake tubing assembly or prepare an 
air brake tubing assembly with a free length of twelve inches in 
accordance with 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, and fill the assembly with hydraulic fluid and 
bleed any air from the assembly. Increase the hydraulic pressure inside 
the tubing assembly at a constant rate to 50 percent of the burst 
pressure for the size of tubing being tested as specified in Table VIII 
within a period of 5 seconds, and hold this pressure for 30 seconds. 
Then increase the hydraulic pressure inside the tubing assembly at a 
constant rate to the burst pressure for the size of tubing being tested 
as specified in Table VIII within a period of 5 seconds. Visually 
inspect the assembly for leakage or separation at the end fittings.
    S12.25 Thermal conditioning and end fitting retention test.
    (a) Apparatus. A source of hydraulic pressure that includes a 
pressure gauge or monitoring system, uses a petroleum-based hydraulic 
fluid with a pour point of less than minus 40 [deg]F, 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 an 
air brake tubing assembly with a free length of twelve inches in 
accordance with 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 hydraulic fluid and bleed 
any air from the assembly, and place the tubing assembly inside an 
environment chamber. Conduct the following tests:
    (i) With atmospheric pressure applied to the hydraulic fluid inside 
the tubing assembly, set the environmental chamber temperature to 200 
[deg]F and condition the tubing assembly for 24 hours.
    (ii) With the temperature maintained at 200 [deg]F, increase the 
hydraulic pressure inside the tubing assembly at a constant rate to 450 
psig within a period of 5 seconds, and hold this pressure for 5 
minutes.
    (iii) Decrease the pressure inside the tubing assembly to 
atmospheric and set the temperature of the environmental chamber to 75 
[deg]F. Condition the tubing assembly at this temperature for 1 hour.
    (iv) Set the temperature of the environmental chamber to minus 40 
[deg]F and condition the tubing assembly for 24 hours.
    (v) With the temperature maintained at minus 40 [deg]F, increase 
the hydraulic pressure inside the tubing assembly at a constant rate to 
450 psi within a period of 5 seconds, and hold this pressure for 5 
minutes. Visually inspect the assembly for leakage or separation at the 
end fittings.
    S12.26. End fitting serviceability.
    (a) Apparatus. A source of air pressure that includes a pressure 
gauge or monitoring system and is equipped with a mass flow meter.
    (b) Preparation. Prepare a 12 inch length of plastic air brake 
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, and 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 assembly to a pressure of 
120 psi in a period of two seconds. If the end fitting leaks, measure 
and record the leakage rate using the mass air flow meter.
    S12.27 End fitting corrosion resistance. Conduct the test specified 
in S6.9 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 [deg]F.

    S13.2 Unless otherwise indicated, the test samples are stabilized 
at test room temperature prior to testing.
    S13.3 The brake hoses and brake hose assemblies are at least 24 
hours old, and unused.
    S13.4. Specified test pressures are gauge pressures (psig).

    Issued: May 1, 2003.
Stephen R. Kratzke,
Associate Administrator for Rulemaking.
[FR Doc. 03-11292 Filed 5-14-03; 8:45 am]
BILLING CODE 4910-59-P