[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]
[[Page 26383]]
-----------------------------------------------------------------------
Part II
Department of Transportation
-----------------------------------------------------------------------
National Highway and Traffic Safety Administration
-----------------------------------------------------------------------
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
[[Page 26384]]
-----------------------------------------------------------------------
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.
-----------------------------------------------------------------------
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
[[Page 26385]]
(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\
---------------------------------------------------------------------------
\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
[[Page 26386]]
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
[[Page 26387]]
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