Title 49, § 571.106
Brake Hoses
S1. Scope. This standard specifies labeling and performance requirements
for motor vehicle brake hose, brake hose assemblies, and brake hose
end fittings.
S2. Purpose. The purpose of this standard is to reduce deaths and
injuries occurring as a result of brake system failure from pressure
or vacuum loss due to hose or hose assembly rupture.
S3. Application. This standard applies to passenger cars, multipurpose
passenger vehicles, trucks, buses, trailers, and motorcycles, and
to hydraulic, air, and vacuum brake hose, brake hose assemblies,
and brake hose end fittings for use in those vehicles.
S4. Definitions.
Armor means protective material installed on a brake hose to increase
the resistance of the hose or hose assembly to abrasion or impact
damage.
Brake hose means a flexible conduit, other than a vacuum tubing
connector, manufactured for use in a brake system to transmit or
contain the fluid pressure or vacuum used to apply force to a vehicle's
brakes. For hose, a dimensional description such as ``\1/4\-inch
hose'' refers to the nominal inside diameter. For tubing, a dimensional
description such as ``\1/4\-in tubing'' refers to the nominal outside
diameter.
Brake hose assembly means a brake hose, with or without armor,
equipped with end fittings for use in a brake system, but does not
include an air or vacuum assembly prepared by the owner or operator
of a used vehicle, by his employee, or by a repair facility, for
installation in that used vehicle.
Brake hose end fitting means a coupler, other than a clamp, designed
for attachment to the end of a brake hose.
Free length means the linear measurement of hose exposed between
the end fittings of a hose assembly in a straight position.
Permanently attached end fitting means an end fitting that is attached
by deformation of the fitting about the hose by crimping or swaging,
or an end fitting that is attached by use of a sacrificial sleeve
or ferrule that requires replacement each time a hose assembly is
rebuilt.
Rupture means any failure that results in separation of a brake
hose from its end fitting or in leakage.
Vacuum tubing connector means a flexible conduit of vacuum that
(i) connects metal tubing to metal tubing in a brake system,
(ii) is attached without end fittings, and
(iii) when installed, has an unsupported length less than the total
length of those portions that cover the metal tubing.
S5. Requirements--hydraulic brake hose, brake hose assemblies,
and brake hose end fittings.
S5.1 Construction.
(a) Each hydraulic brake hose assembly shall have permanently attached
brake hose end fittings which are attached by deformation of the
fitting about the hose by crimping or swaging.
(b) Each hydraulic brake hose assembly that is equipped with a
permanent supplemental support integrally attached to the assembly
and is manufactured as a replacement for use on a vehicle not equipped,
as an integral part of the vehicle's original design, with a means
of attaching the support to the vehicle shall be equipped with a
bracket that is integrally attached to the supplemental support
and that adapts the vehicle to properly accept this type of brake
hose assembly.
S5.2 Labeling.
S5.2.1 Each hydraulic brake hose, except hose sold as part of a
motor vehicle, shall have at least two clearly identifiable stripes
of at least one-sixteenth of an inch in width, placed on opposite
sides of the brake hose parallel to its longitudinal axis. One stripe
may be interrupted by the information required by S5.2.2, and the
other stripe may be interrupted by additional information at the
manufacturer's option. However, hydraulic brake hose manufactured
for use only in an assembly whose end fittings prevent its installation
in a twisted orientation in either side of the vehicle, need not
meet the requirements of S5.2.1.
S5.2.2 Each hydraulic brake hose shall be labeled, or cut from
bulk hose 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 hose
that is sold as part of a brake hose assembly or 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 hose,
which shall be filed in writing with: Office of Crash Avoidance
Standards, Vehicle Dynamics Division, National Highway Traffic Safety
Administration, 400 Seventh Street, SW., Washington, DC 20590. The
marking may consist of a designation other than block capital letters
required by S5.2.2.
(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 inside diameter of the hose expressed in inches
or fractions of inches, or in millimeters followed by the abbreviation
``mm.''
(e) Either ``HR'' to indicate that the hose is regular expansion
hydraulic hose or ``HL'' to indicate that the hose is low expansion
hydraulic hose.
S5.2.3 Package labeling for brake hose assemblies designed to be
used with a supplemental support.
(a) Each hydraulic brake hose assembly that is equipped with a
permanent supplemental support integrally attached to the assembly
and is manufactured as a replacement assembly for a vehicle equipped,
as an integral part of the vehicle's original design, with a means
of attaching the support to the vehicle shall be sold in a package
that is marked or labeled as follows: ``FOR USE ON [insert Manufacturer,
Model Name] ONLY'';
(b) Each hydraulic brake hose assembly that is equipped with a
permanent supplemental support integrally attached to the assembly
and is manufactured as a replacement for use on a vehicle not equipped,
as an integral part of the vehicle's original design, with a means
of attaching the support to the vehicle shall comply with paragraphs
(a) (1) and (2) of this section:
(1) Be sold in a package that is marked or labeled as follows:
``FOR USE ONLY WITH A SUPPLEMENTAL SUPPORT.''
(2) Be accompanied by clear, detailed instructions explaining the
proper installation of the brake hose and the supplemental support
bracket to the vehicle and the consequences of not attaching the
supplemental support bracket to the vehicle. The instructions shall
be printed on or included in the package specified in paragraph
(a)(1) of this section.
S5.2.4 Each hydraulic brake hose assembly, except those sold as
part of a motor vehicle, shall be labeled by means of a band around
the brake hose assembly as specified in this paragraph or, at the
option of the manufacturer, by means of labeling as specified in
S5.2.4.1. 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 hose assembler
that the hose 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 Crash
Avoidance Standards, Vehicle Dynamics Division, National Highway
Traffic Safety Administration, 400 Seventh Street SW., Washington,
DC 20590. The designation may consist of block capital letters,
numerals or a symbol.
S5.2.4.1 At least one end fitting of a hydraulic brake hose assembly
shall be etched, stamped or embossed with a designation at least
one-sixteenth of an inch high that identifies the manufacturer of
the hose assembly and is filed in accordance with S5.2.4(b).
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
S11 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
S5.3.11.
S5.3.1 Constriction. Except for that part of an end fitting which
does not contain hose, every inside diameter of any section of a
hydraulic brake hose assembly shall be not less than 64 percent
of the nominal inside diameter of the brake hose.
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 5,000
psi (S6.2).
Table 1--Maximum Expansion of Free Length
Brake Hose, cc/ft
|
|
Test Pressure
|
|
1,000 psi
|
1,500 psi
|
Hydraulic brake hose, inside diameter |
Regular Expansion Hose |
Low Expansion Hose |
Regular Expansion Hose |
Low Expansion Hose |
1/8 inch or 3 mm or less |
0.66
|
0.33
|
0.79
|
0.42
|
3/16 inch or 4 to 5 mm |
.86
|
.55
|
1.02
|
.72
|
1/4 inch or 6 mm or more |
1.04
|
.82
|
1.30
|
1.17
|
S5.3.3 Whip resistance. A hydraulic brake hose assembly shall not
rupture when run continuously on a flexing machine for 35 hours
(S6.3).
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 (S6.4).
S5.3.5 Water absorption and burst strength. A hydraulic brake hose
assembly, after immersion in water for 70 hours (S6.5), shall withstand
water pressure of 4,000 psi for 2 minutes, and then shall not rupture
at less than 5,000 psi (S6.2).
S5.3.6 Water absorption and tensile strength. A hydraulic brake
hose assembly, after immersion in water for 70 hours (S6.5), shall
withstand a pull of 325 pounds without separation of the hose from
its end fittings (S6.4).
S5.3.7 Water absorption and whip resistance. A hydraulic brake
hose assembly, after immersion in water for 70 hours (S6.5), shall
not rupture when run continuously on a flexing machine for 35 hours
(S6.3).
S.5.3.8 Low-temperature resistance. A hydraulic brake hose conditioned
at minus 40 deg.F. for 70 hours shall not show cracks visible without
magnification when bent around a cylinder as specified in S6.6.
(S6.6)
S5.3.9 Brake fluid compatibility, constriction, and burst strength.
Except for brake hose assemblies designed for use with mineral or
petroleum-based brake fluids, a hydraulic brake hose assembly shall
meet the constriction requirement of S5.3.1 after having been subjected
to a temperature of 200 deg.F for 70 hours while filled with SAE
RM-66-04 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). (SAE RM-66-03 Compatibility
Fluid, as described in appendix A of SAE Standard J1703 NOV83, ``Motor
Vehicle Brake Fluid,'' November 1983, may be used in place of SAE
RM-66-04 until January 1, 1995.)
S5.3.10 Ozone resistance. A hydraulic brake hose shall not show
cracks visible under 7-power magnification after exposure to ozone
for 70 hours at 104 deg.F. (S6.8). S5.3.11 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.
(S6.9)
S6. Test procedures--Hydraulic brake hose, brake hose assemblies,
and brake hose end fittings.
S6.1. Expansion test.
S6.1.1 Apparatus. Utilize a test apparatus (as shown in Figure
1) which consists of:
(a) Source for required fluid pressure;
(b) Test fluid of water without any additives and free of gases;
(c) Reservoir for test fluid;
(d) Pressure gauges;
(e) Brake hose end fittings in which to mount the hose vertically;
and
(f) Graduate burette with 0.05 cc increments.
[GRAPHIC] [TIFF OMITTED]
TC01AU91.006 Fig. 1. Expansion Test Apparatus
S6.1.2 Preparation.
(a) Measure the free length of the hose assembly.
(b) Mount the hose so that it is in a vertical straight position
without tension when pressure is applied.
(c) Fill the hose with test fluid and bleed all gases from the
system.
(d) Close the valve to the burette and apply 1,500 psi for 10 seconds;
then release pressure. S6.1.3 Calculation of expansion at 1,000
and 1,500 psi.
(a) Adjust the fluid level in the burette to zero.
(b) Close the valve to the burette, apply pressure at the rate
of 15,000 psi per minute, and seal 1,000 psi in the hose (1,500
psi in second series).
(c) After 3 seconds open the valve to the burette for 10 seconds
and allow the fluid in the expanded hose to rise into the burette.
(d) Repeat the procedure in steps (b) and (c) twice. Measure the
amount of test fluid which has accumulated in the burette as a result
of the three applications of pressure.
(e) Calculate the volumetric expansion per foot by dividing the
total accumulated test fluid by 3 and further dividing by the free
length of the hose in feet.
S6.2 Burst strength test.
(a) Connect the brake hose to a pressure system and fill it completely
with water, allowing all gases to escape.
(b) Apply water pressure of 4,000 psi at a rate of 15,000 psi per
minute.
(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.
S6.3 Whip resistance test.
S6.3.1 Apparatus. Utilize test apparatus that is dynamically balanced
and includes:
(a) A movable header consisting of a horizontal bar equipped with
capped end fittings and mounted through bearings at each end to
points 4 inches from the center of two vertically rotating disks
whose edges are in the same vertical plane;
(b) An adjustable stationary header parallel to the movable header
in the same horizontal plane as the centers of the disks, and fitted
with open end fittings;
(c) An elapsed time indicator; and
(d) A source of water pressure connected to the open end fittings.
S6.3.2 Preparation.
(a) Except for the supplemental support specified in S6.3.2(d),
remove all external appendages including, but not limited to, hose
armor, chafing collars, mounting brackets, date band and spring
guards.
(b) Measure the hose free length.
(c) Mount the hose in the whip test machine, introducing slack
as specified in Table II for the size hose tested, measuring the
projected length parallel to the axis of the rotating disks. The
manufacturer may, at his option, adapt the fitting attachment points
to permit mounting hose assemblies equipped with angled or other
special fittings in the same orientation as hose assemblies equipped
with straight fittings.
(d) In the case of a brake hose assembly equipped with a permanent
supplemental support integrally attached to the assembly, the assembly
may be mounted using the supplemental support and associated means
of simulating its attachment to the vehicle. Mount the supplemental
support in the same vertical and horizontal planes as the stationary
header end of the whip test fixture described in S6.3.1(b). Mount
or attach the supplemental support so that it is positioned in accordance
with the recommendation of the assembly manufacturer for attaching
the supplemental support on a vehicle.
Table II -- Hose Lengths
|
Free length between end fittings (inches)
|
Slack (inches)
|
|
1/8 inch or 3mm hose or less
|
more than 1/8 inch or 3mm hose |
8 to 15 1/2, inclusive
|
1.750
|
|
10 to 15 1/2, inclusive
|
|
1,000
|
Over 15 1/2 to 19 inclusive
|
1.250
|
|
Over 19 to 24, inclusive
|
0.750
|
|
S6.3.3 Operation.
(a) Apply 235 psi water pressure and bleed all gases from the
system.
(b) Drive the movable head at 800 rpm.
S6.4 Tensile strength test. Utilize a tension testing machine conforming
to the requirements of the methods of Verification of Testing Machines
(1964 American Society for Testing and Materials, Designation E4),
and provided with a recording device to give the total pull in pounds.
S6.4.1 Preparation. Mount the hose assembly to ensure straight,
evenly distributed machine pull.
S6.4.2 Operation. Apply tension at a rate of 1 inch per minute
travel of the moving head until separation occurs. S6.5 Water absorption
sequence tests.
S6.5.1 Preparation. Prepare three hose assemblies as follows:
(a) Remove 1\1/8\ inches of hose cover, if any, from the center
of the hose assemblies without injury to any reinforcing material
or elongation of the hose assemblies.
(b) Measure the free length of the hose assemblies. S.6.5.2 Immersion
and sequence testing.
(a) Immerse the hose assemblies in distilled water for 70 hours.
(b) Thirty minutes after removal from water, conduct tests S6.2,
S6.3, and S6.4, using a different hose for each sequence. S6.6 Low
temperature resistance test.
S6.6.1 Preparation.
(a) Remove hose armor, if any, and condition a hose in a straight
position in air at minus 40 deg.F. for 70 hours.
(b) Condition a cylinder in air at minus 40 deg.F for 70 hours,
using a cylinder of 2\1/2\ inches diameter for test of hose less
than \1/8\ inch or 3 mm 3 inches for tests of \1/8\ inch or 3mm
hose, 3\1/2\ inches for tests of \3/16\ and \1/4\ inch hose or of
4 to 6 mm hose, and 4 inches for tests of hose greater than \1/4\
inch or 6 mm in diameter.
S6.6.2 Flexibility testing. Bend the conditioned hose 180 degrees
around the conditioned cylinder at a steady rate in a period of
3 to 5 seconds. Examine without magnification for cracks. S6.7 Brake
fluid compatibility test.
S6.7.1 Preparation.
(a) Attach a hose assembly below a 1-pint reservoir filled with
100 ml. of SAE RM-66-04 Compatibility Fluid as shown in Figure 2.
(SAE RM-66-03 Compatibility Fluid, as described in appendix A of
SAE Standard J1703 NOV83, ``Motor Vehicle Brake Fluid,'' November
1983, may be used in place of SAE RM-66-04 until January 1, 1995.)
(b) Fill the hose assembly with brake fluid, seal the lower end,
and place the test assembly in an oven in a vertical position.
[GRAPHIC] [TIFF OMITTED] TC01AU91.007
S6.7.2 Oven treatment.
(a) Condition the hose assembly at 200 deg.F. for 70 hours.
(b) Cool the hose assembly at room temperature for 30 minutes.
(c) Drain the brake hose assembly, immediately determine that
every inside diameter of any section of the hose assembly, except
for that part of an end fitting which does not contain hose, is
not less than 64 percent of the nominal inside diameter of the hose,
and conduct the test specified in
S6.2. S6.8 Ozone resistance test. Utilize a cylinder with a diameter
eight times the nominal outside diameter of the brake hose excluding
armor.
S6.8.1 Preparation. After removing any armor, bind a hydraulic
brake hose 360 deg. around the cylinder. In the case of hose shorter
than the circumference of the cylinder, bend the hose so that as
much of its length as possible is in contact. S6.8.2 Exposure to
ozone.
(a) Condition the hose on the cylinder in air at room temperature
for 24 hours.
(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 50 parts of ozone per 100 million parts of
air by volume.
(c) Examine the hose for cracks under 7-power magnification, ignoring
areas immediately adjacent to or within the area covered by binding.
S6.9 End fitting corrosion resistance test. Utilize the apparatus
described in ASTM B117-64, ``Salt Spray (Fog) Testing''.
S6.9.1 Construction. Construct the salt spray chamber so that:
(a) The construction material does not affect the corrosiveness
of the fog.
(b) The hose assembly is supported or suspended 30 deg. from the
vertical and parallel to the principal direction of the horizontal
flow of fog through the chamber.
(c) The hose assembly does not contact any metallic material or
any material capable of acting as a wick.
(d) Condensation which falls from the assembly does not return
to the solution reservoir for respraying.
(e) Condensation from any source does not fall on the brake hose
assemblies or the solution collectors.
(f) Spray from the nozzles is not directed onto the hose assembly.
S6.9.2 Preparation.
(a) Plug each end of the hose assembly.
(b) Mix a salt solution five parts by weight of sodium chloride
to 95 parts of distilled water, using sodium chloride substantially
free of nickel and copper, and containing on a dry basis not more
than 0.1 percent of sodium iodide and not more than 0.3 percent
total impurities. Ensure that the solution is free of suspended
solids before the solution is atomized.
(c) After atomization at 95 deg.F. ensure that the collected solution
is in the PH range of 6.5 to 7.2. Make the PH measurements at 77
deg.F.
(d) Maintain a compressed air supply to the nozzle or nozzles free
of oil and dirt and between 10 and 25 psi.
S6.9.3 Operation. Subject the brake hose assembly to the salt spray
continuously for 24 hours.
(a) Regulate the mixture so that each collector will collect from
1 to 2 ml. of solution per hour for each 80 square centimeters of
horizontal collecting area.
(b) Maintain exposure zone temperature at 95 deg.F.
(c) Upon completion, remove the salt deposit from the surface of
the hoses by washing gently or dipping in clean running water not
warmer than 100 deg.F. and then drying immediately.
S7. Requirements--Air brake hose, brake hose assemblies, and brake
hose end fittings.
S7.1 Construction. Each air brake hose assembly shall be equipped
with permanently attached brake hose end fittings or reusable brake
hose end fittings. Each air brake hose constructed of synthetic
or natural elastomeric rubber intended for use with reusable end
fittings shall conform to the dimensional requirements specified
in Table III.
Table III -- Air Brake Hose Dimensions for
Reusable Assemblies
|
Size (inches)
|
Inside diameter tolerance, inches
|
Type 1 outside diameter (inches)
|
Type 2 outside diameter (inches)
|
3/16
|
+0.026
-0.000
|
0.472
|
0.510
|
0.500
|
0.539
|
1/4
|
+0.031
-0.000
|
0.535
|
0.573
|
0.562
|
0.602
|
5/16
|
+0.031
-0.000
|
0.598
|
0.636
|
0.656
|
0.695
|
3/8
|
[plusmn] 0.023
|
0.719
|
0.781
|
0.719
|
0.781
|
13/32
|
+0.039
-0.000
|
0.714
|
0.760
|
0.742
|
0.789
|
1/2
|
+0.039
-0.000
|
0.808
|
0.854
|
0.898
|
0.945
|
5/8
|
+0.042
-0.000
|
0.933
|
0.979
|
1.054
|
1.101
|
1/2 special
|
[pulsmn] 0.031
|
0.844
|
.906
|
0.844
|
0.906
|
S7.2 Labeling
S7.2.1 Hose. Each air brake hose shall be labeled, or cut from
bulk hose 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 hose
that is sold as part of a brake hose assembly or 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 hose,
which shall be filed in writing with: Office of Crash Avoidance
Standards, Vehicle Dynamics Division, National Highway Traffic Safety
Administration, 400 Seventh Street SW., Washington, DC 20590. The
designation may consist of block capital letters, numerals, or a
symbol.
(c) The month, day, and year, or the month and year, of manufacture,
expressed in numerals. For example, 10/1/96 means October 1, 1996.
(d) The nominal inside diameter of the hose expressed in inches
or fractions of inches or in millimeters, or the nominal outside
diameter of plastic tubing expressed in inches or fractions of inches
or in millimeters followed by the letters OD. The abbreviation ``mm''
shall follow hose sizes that are expressed in millimeters. (Examples
of inside diameter: \1/8\, \1/2\ (\1/2\SP in the case of \1/2\ inch
special air brake hose), 4 mm, 6 mm. Examples of outside diameter:
\1/4\ OD, 12 mm OD.)
(e) The letter ``A'' shall indicate intended use in air brake
systems. In the case of a hose constructed of synthetic or natural
elastomeric rubber 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.
S7.2.2 End fittings. Except for an end fitting that is attached
by deformation of the fitting about a hose by crimping or swaging,
at least one component of each air brake hose 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
Crash Avoidance Standards, Vehicle Dynamics Division, National Highway
Traffic Safety Administration, 400 Seventh Street SW., Washington,
DC 20590. The designation may consist of block capital letters,
numerals, or a symbol.
(c) The letter ``A'' shall indicate intended use in air brake
systems. In the case of an end fitting intended for use in a reusable
assembly with brake hose subject to Table III, ``AI'' or ``AII''
shall indicate use with Type I or Type II hose, respectively.
(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, or the 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
(See examples in S7.2.1(d)). The abbreviations ``mm'' shall follow
hose sizes that are expressed in millimeters.
S7.2.3 Assemblies. Each air brake hose 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 hose assembly as specified in this paragraph or, at the option
of the manufacturer, by means of labeling as specified in S7.2.3.1.
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 hose assembler
that the hose 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 Crash
Avoidance Standards, Vehicle Dynamics Division, National Highway
Traffic Safety Administration, 400 Seventh Street SW., Washington,
DC 20590. The designation may consist of block capital letters,
numerals or a symbol.
S7.2.3.1 At least one end fitting of an air brake hose 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 hose assembly and is filed in accordance with S7.2.3(b).
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
S11 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 S7.3.13.
S7.3.1 Construction. Except for that part of an end fitting which
does not contain hose, every inside diameter of any section of an
air brake hose assembly shall be not less than 66 percent of the
nominal inside diameter of the brake hose.
S7.3.2 High temperature resistance. An air brake hose shall not
show external or internal cracks, charring, or disintegration visible
without magnification when straightened after being bent for 70
hours at 212 deg.F. over a cylinder having the radius specified
in Table IV for the size of hose tested (S8.1)
. S7.3.3 Low temperature resistance. The outer cover of an air
brake hose shall not show cracks visible without magnification 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)* |
1/8 |
3/16 |
1/4 |
5/16 |
3/8, 13/32 |
7/16, 1/2 |
5/8 |
Nominal hose diameter (milimeters)* |
3 |
4,5 |
6 |
8 |
10 |
12 |
16 |
Radius of test cylinder (inches) |
1 1/2 |
2 |
2 1/2 |
3 |
3 1/2 |
4 |
4 1/2 |
*These sizes are listed to provide test values for brake hoses
manufactured in these sizes. They do not represent conversions.
S7.3.4 Oil resistance. After immersion in ASTM No. 3 oil for 70
hours at 212 deg.F. the volume of a specimen prepared from the inner
tube and cover of an air brake hose shall not increase more than
100 percent (S8.3).
S7.3.5 Ozone resistance. The outer cover of an air brake hose shall
not show cracks visible under 7-power magnification after exposure
to ozone for 70 hours at 104 deg.F. (S8.4).
S7.3.6 Length change. An airbrake hose (other than a coiled nylon
tube for use in an assembly that meets the requirements of Sec.
393.45 of this title) 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. Except for hose reinforced by wire, an airbrake
hose shall withstand a tensile force of 8 pounds per inch of length
before separation of adjacent layers (S8.6).
S7.3.8 Air pressure. An air brake hose assembly shall contain air
pressure of 200 psi for 5 minutes without loss of more than 5 psi
(S8.7).
S7.3.9 Burst strength. An air brake hose assembly shall not rupture
when exposed to hydrostatic pressure of 800 psi (S8.8).
S7.3.10 Tensile strength. An air brake hose assembly (other than
a coiled nylon tube assembly which meets the requirements of Sec.
393.45 of this title) designed for use between frame and axle or
between a towed and a towing vehicle shall withstand, without separation
of the hose from its end fittings, a pull of 250 pounds if it is
\1/4\ inch or less or 6 mm or less in nominal internal diameter,
or a pull of 325 pounds if it is larger than \1/4\ inch or 6 mm
in nominal internal diameter. An air brake hose assembly designed
for use in any other application shall withstand, without separation
of the hose from its end fitting, a pull of 50 pounds if it is \1/4\
inch or 6 mm or less in nominal internal diameter, 150 pounds if
it is \3/8\ or \1/2\ inch or 10 mm to 12 mm in nominal internal
diameter, or 325 pounds if it is larger than \1/2\ inch or 12 mm
in nominal internal 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
(other than a coiled tube assembly which meets the requirements
of Sec. 393.45 of this title) designed for use between frame and
axle or between a towed and a towing vehicle shall withstand without
separation of the hose from its end fittings a pull of 250 pounds
if it is \1/4\ inch or 6 mm or less in nominal internal diameter,
or a pull of 325 pounds if it is larger than \1/4\ inch or 6 mm
in nominal internal diameter. After immersion in distilled water
for 70 hours (S8.10), an air brake hose assembly designed for use
in any other application shall withstand without separation of the
hose from its end fitting a pull of 50 pounds if it is \1/4\ inch
or 6 mm or less in nominal internal diameter, 150 pounds if it is
\3/8\ inch or \1/2\ inch or 10 to 12 mm in nominal internal diameter,
or 325 pounds if it is larger than \1/2\ inch or 12 mm in nominal
internal diameter (S8.9).
S7.3.12 Zinc chloride resistance. The outer cover of an air brake
hose shall not show cracks visible under 7-power magnification after
immersion in a 50 percent zinc chloride aqueous solution for 200
hours (S8.11).
S7.3.13 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.
S8. Test procedures--Air brake hose, brake hose assemblies, and
brake hose end fittings
S8.1 High temperature resistance test.
(a) Utilize a cylinder having the radius indicated in Table IV
for the size of hose tested.
(b) Bind the hose around the cylinder and condition it in an air
oven for 70 hours at 212 deg.F.
(c) Cool the hose to room temperature, remove it from the cylinder
and straighten it.
(d) Without magnification, examine the hose externally and cut
the hose lengthwise and examine the inner tube.
S8.2 Low temperature resistance test.
(a) Utilize a cylinder having the radius indicated in Table IV
for the size of hose tested.
(b) Condition the cylinder and the brake hose, in a straight position,
in a cold box at minus 40 deg.F. for 70 hours.
(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.
S8.3 Oil resistance test. Utilize three test specimens and average
the results.
S8.3.1 Preparation. Fashion a test specimen by cutting a rectangular
block 2 inches long and not less than one-third of an inch in width,
having a thickness of not more than one-sixteenth inch, from the
brake hose and buff the specimen on both faces to ensure smooth
surfaces.
S8.3.2 Measurement.
(a) Weigh each specimen to the nearest milligram in air (W1) and
in distilled water (W2) at room temperature. If wetting is necessary
to remove air bubbles, dip the specimen in acetone and thoroughly
rinse it with distilled water.
(b) Immerse each specimen in ASTM No. 3 oil for 70 hours at 212
deg.F. and then cool in ASTM No. 3 oil at room temperature for 30
to 60 minutes.
(c) Dip the specimen quickly in acetone and blot it lightly with
filter paper.
(d) Weigh each specimen in a tared weighing bottle (W3) and in
distilled water (W4) within five minutes of removal from the cooling
liquid.
(e) Calculate the percentage increase in volume follows:
Percent of increase=
[(W3-W4)-(W1-W2)]/ (W1-W2) x 100
S8.4 Ozone resistance test. Conduct the test specified in S6.8
using air brake hose.
S8.5 Length change test.
(a) Position a test hose in a straight, horizontal position, and
apply air pressure of 10 psi thereto.
(b) Measure the hose to determine original free length.
(c) Without releasing the 10 psi, raise the air pressure to the
test hose to 200 psi.
(d) Measure the hose under 200 psi to determine final free length.
An elongation or contraction is an increase or decrease, respectively,
in the final free length from the original free length of the hose.
S8.6 Adhesion test.
S8.6.1 Apparatus. A tension testing machine that is power-driven
and that applies a constant rate of extension is used for measuring
the force required to separate the layers of the test specimen.
The apparatus is constructed so that:
(a) The recording head includes a freely rotating form with an
outside diameter substantially the same as the inside diameter of
the hose specimen to be placed on it.
(b) The freely rotating form is mounted so that its axis of rotation
is in the plane of the ply being separated from the specimen and
so that the applied force is perpendicular to the tangent of the
specimen circumference at the line of separation.
(c) The rate of travel of the power-actuated grip is a uniform
one inch per minute and the capacity of the machine is such that
maximum applied tension during the test is not more than 85 percent
nor less than 15 percent of the machine's rated capacity.
(d) The machine produces a chart with separation as one coordinate
and applied tension as the other.
S8.6.2 Preparation.
(a) Cut a test specimen of 1 inch or more in length from the hose
to be tested and cut the layer to be tested of that test specimen
longitudinally along its entire length to the level of contact with
the adjacent layer.
(b) Peel the layer to be tested from the adjacent layer to create
a flap large enough to permit attachment of the power-actuated clamp
of the apparatus.
(c) Mount the test specimen on the freely rotating form with the
separated layer attached to the power-actuated clamp.
S8.6.3 [Reserved]
S8.6.4 Calculations.
(a) The adhesion value shall be the minimum force recorded on the
chart excluding that portion of the chart which corresponds to the
initial and final 20 percent portion along the displacement axis.
(b) Express the force in pounds per inch of length.
S8.7 Air pressure test.
(a) Connect the air brake hose assembly to a source of air pressure.
(b) Apply 200 psi air pressure to the hose and seal the hose from
the source of air pressure.
(c) After 5 minutes, determine the air pressure remaining in the
test specimen.
S8.8 Burst strength test.
(a) Utilize an air brake 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 the Methods of Verification of Testing Machines
(1964 American Society for Testing and Materials, Designation E4),
and provided with a recording device to register total pull in pounds.
(a) Attach an air brake hose assembly to the testing machine to
permit straight, even, machine-pull on the hose.
(b) Apply tension at a rate of 1 inch per minute travel of the
moving head until separation occurs. S8.10 Water Absorption and
tensile strength test. Immerse an air brake hose assembly in distilled
water at room temperature for 70 hours. Thirty minutes after removal
from the water, conduct the test specified in
S8.9. S8.11 Zinc chloride resistance test. Immerse an air brake
hose in a 50 percent zinc chloride aqueous solution at room temperature
for 200 hours. Remove it from the solution and examine it under
7-power magnification for cracks.
S8.12 End fitting corrosion resistance test. Conduct the test specified
in S6.9 using an air brake hose assembly.
S9. Requirements--vacuum brake hose, brake hose assemblies, and
brake hose end fittings.
S9.1 Labeling.
S9.1.1 Hose. Each vacuum brake hose shall be labeled, or cut from
bulk hose 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 hose
that is sold as part of a brake hose assembly or 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 hose,
which shall be filed in writing with: Office of Crash Avoidance
Standards, Vehicle Dynamics Division, National Highway Traffic Safety
Administration, 400 Seventh Street, SW., Washington, DC 20590. The
designation may consist of block capital letters, numerals or a
symbol.
(c) The month, day, and year, or the month and year, of manufacture,
expressed in numerals. For example, 10/1/96 means October 1, 1996.
(d) The nominal inside diameter of the hose expressed in inches
or fractions of inches or in millimeters, or the nominal outside
diameter of plastic tubing expressed in inches or fractions of inches
or in millimeters followed by the letters OD. The abbreviation ``mm''
shall follow hose sizes that are expressed in millimeters. (Example
of inside diameter: \7/32\, \1/4\, 4 mm. Example of outside diameter:
\1/4\ OD, 12 mm OD.)
(e) The letters ``VL'' or ``VH'' shall indicate that the component
is a light-duty vacuum brake hose or heavy-duty vacuum brake hose,
respectively.
S9.1.2 End fittings. Except for an end fitting that is attached
by heat striking or by interference fit with plastic vacuum hose
or that is attached by deformation of the fitting about a hose by
crimping or swaging, at least one component of each vacuum brake
hose 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
Crash Avoidance Standards, Vehicle Dynamics Division, National Highway
Traffic Safety Administration, 400 Seventh Street, SW., Washington,
DC 20590. The designation may consist of block capital letters,
numerals or a symbol.
(c) The letters ``VL'' or ``VH'' shall indicate that the end fitting
is intended for use in a light-duty or heavy-duty vacuum brake system,
respectively.
(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, or the outside diameter of the plastic tubing
to which the fitting is properly attached expressed in inches or
fraction of inches or in millimeters followed by the letter OD (See
examples in S9.1.1(d)). The abbreviation ``mm'' shall follow hose
sizes that are expressed in millimeters.
S9.1.3 Assemblies. Each vacuum brake hose assembly made with end
fittings that are attached by crimping or swaging and each plastic
tube assembly made with end fittings that are attached by heat shrinking
or dimensional interference fit, except those sold as part of a
motor vehicle, shall be labeled by means of a band around the brake
hose assembly as specified in this paragraph or, at the option of
the manufacturer, by means of labeling as specified in S9.1.3.1.
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 hose assembler
that the hose 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 Crash
Avoidance Standards, Vehicle Dynamics Division, National Highway
Traffic Safety Administration, 400 Seventh Street SW., Washington,
DC 20590. The designation may consist of block capital letters,
numerals or a symbol.
S9.1.3.1 At least one end fitting of a vacuum brake hose assembly
made with end fittings that are attached by crimping or swaging,
or of a plastic tubing assembly made with end fittings that are
attached by heat shrinking or dimensional interference fit shall
be etched, stamped or embossed with a designation at least one-sixteenth
of an inch high that identifies the manufacturer of the hose assembly
and is filed in accordance with S9.1.3(b).
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
S11. and the applicable procedures of S10. However, a particular
hose assembly or appropriate part thereof need not meet further
requirements after having met the construction requirement (S9.2.1)
and then having been subjected to any one of the requirements specified
in S9.2.2 through S9.2.11.
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 the hose if for light
duty.
S9.2.2 High temperature resistance. A vacuum brake hose shall
not show external or internal cracks, charring, or disintegration
visible without magnification when straightened after being bent
for 70 hours at 212 deg.F. over a cylinder having the radius specified
in Table V for the size of hose tested (S10.1).
S9.2.3 Low temperature resistance. A vacuum brake hose shall 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 (S10.2).
S9.2.4 Ozone resistance. A vacuum brake hose shall not show cracks
visible under 7-power magnification after exposure to ozone for
70 hours (S10.3).
S9.2.5 Burst strength. A vacuum brake hose shall not rupture under
hydrostatic pressure of 350 psi (S10.4).
S9.2.6 Vacuum. The collapse of the outside diameter of a vacuum
brake hose under internal vacuum of 26 inches of Hg. for five minutes
shall not exceed one-sixteenth of an inch (S10.5).
S9.2.7 Bend. The collapse of the outside diameter of a 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).
Table V--Vacuum Brake Hose Test Requirements
|
|
|
Hose inside diameter*
|
High temperature resistance
|
Low temperature resistance
|
Bend
|
|
Inches
|
Millimeters
|
Hose length (inches)
|
Radius of cylinder (inches)
|
Hose length (inches)
|
Radius of cylinder (inches)
|
Hose length (inches)
|
Maximum collapse of outside diameter (inches)
|
Deformation--collapsed inside diameter (inches)
|
7/32
|
5
|
8
|
1 1/2
|
17 1/2
|
3
|
7
|
11/64
|
3/64
|
1/4
|
6
|
9
|
1 1/2
|
17 1/2
|
3
|
8
|
3/32
|
1/16
|
9/32
|
|
9
|
1 3/4
|
19
|
3 1/2
|
9
|
12/64
|
4/64
|
11/32
|
8
|
9
|
1 3/4
|
19
|
3 1/2
|
11
|
13/64
|
5/64
|
3/8
|
10
|
10
|
1 3/4
|
19
|
3 1/2
|
12
|
5/32
|
3/32
|
7/16
|
|
11
|
2
|
20 1/2
|
4
|
14
|
17/64
|
5/64
|
15/32
|
|
11
|
2
|
20 1/2
|
4
|
14
|
17/64
|
5/64
|
1/2
|
12
|
11
|
2
|
20 1/2
|
4
|
16
|
7/32
|
1/8
|
5/8
|
16
|
12
|
2 1/4
|
22
|
4 1/2
|
22
|
7/32
|
5/32
|
3/4
|
|
14
|
2 1/2
|
24
|
5
|
28
|
7/32
|
3/16
|
1
|
|
16
|
3 1/4
|
28 1/2
|
6 1/2
|
36
|
9/32
|
1/4
|
*These sizes are listed to provide test values for brake hoses
manufactured in these sizes. They do not represent conversions.
S9.2.8 Swell. Following exposure to Reference Fuel A, every inside
diameter of any section of a vacuum brake hose shall not be less
than 75 percent of the nominal inside 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 and there
shall be no separation of the inner tube from the fabric reinforcement
of the hose in a vacuum test of 26 inches of Hg for 10 minutes (S10.7).
S9.2.9 Adhesion. Except for hose reinforced by wire, a vacuum brake
hose shall withstand a force of 8 pounds per inch of length before
separation of adjacent layers (S10.8).
S9.2.10 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 lightduty 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).
S9.2.11 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. Conduct the test specified
in S8.1 using vacuum brake hose with the cylinder radius specified
in Table V for the size of hose tested.
S10.2 Low temperature resistance test. 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.
S10.3 Ozone resistance test. Conduct the test specified in S6.8
using vacuum brake hose.
S10.4 Burst strength test. Conduct the test specified in S8.8 using
vacuum brake hose.
S10.5 Vacuum test. Utilize a 12-inch vacuum brake hose assembly
sealed at one end.
(a) Measure the hose outside diameter.
(b) Attach the hose to a source of vacuum and subject it to a vacuum
of 26 inches of Hg for 5 minutes.
(c) Measure the hose to determine the minimum outside diameter
while the hose is still subject to vacuum.
S10.6 Bend test.
(a) Bend a vacuum brake hose, of the length prescribed in Table
V, in the direction of its normal curvature until the ends just
touch as shown in Figure 3.
(b) Measure the outside diameter of the specimen at point A before
and after bending.
(c) The difference between the two measurements is the collapse
of the hose outside diameter on bending.
[GRAPHIC] [TIFF OMITTED] TC01AU91.008 Fig. 3--Bend Test of Vacuum
Brake Hose.
S10.7 Swell test.
(a) Fill a specimen of vacuum brake hose 12 inches long with Reference
Fuel A as described in the Method of Test for Change in Properties
of Elastomeric Vulcanizers Resulting From Immersion in Liquids (1964
American Society for Testing and Materials, designation D471).
(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) Subject the hose specimen to a vacuum of 26 inches of Hg for
10 minutes.
S10.8 Adhesion test. Conduct the test specified in S8.6 using vacuum
brake hose.
S10.9 Deformation test. Table VI specifies the test specimen dimensions.
S10.9.1 Apparatus. Utilize a compression device, equipped to measure
force of at least 100 pounds, and feeler gages of sufficient length
to be passed completely through the test specimen.
S10.9.2 Operation.
(a) Position the test specimen longitudinally in the compression
device with the fabric laps not in the line of the applied pressure.
Table VI--Dimensions of Test Specimen and Feeler
Gage for Deformation Test |
Hose inside diameter* |
Specimen dimensions |
Feeler gage dimensions |
In |
Mm |
Depth (inches) |
Length (inches) |
Width (inches) |
Thickness (inches) |
7/32 |
5 |
3/64 |
1 |
1/8 |
3/64 |
1/4 |
6 |
1/16 |
1 |
1/8 |
1/16 |
9/32 |
|
1/16 |
1 |
1/8 |
1/16 |
11/32 |
8 |
5/64 |
1 |
3/16 |
5/64 |
3/8 |
10 |
3/32 |
1 |
3/16 |
3/32 |
7/16 |
|
5/64 |
1 |
1/4 |
5/64 |
15/32 |
|
5/64 |
1 |
1/4 |
5/64 |
1/2 |
12 |
1/8 |
1 |
1/4 |
1/8 |
5/8 |
16 |
5/32 |
1 |
1/4 |
5/32 |
3/4 |
|
3/16 |
1 |
1/4 |
3/16 |
1 |
|
1/4 |
1 |
1/4 |
1/4 |
*These sizes are listed to provide test values for brake hoses
manufactured in these sizes. They do not represent conversions.
(b) Apply gradually increasing force to the test specimen to compress
its inside diameter to that specified in Table VI (dimension D of
figure 4) for the size of hose tested. [GRAPHIC] [TIFF OMITTED]
TC01AU91.009 Fig. 4. Deformed Specimen of Vacuum Brake Hose
(c) After 5 seconds release the force and record the peak load
applied.
(d) Repeat the procedure four times permitting a 10-second recovery
period between load applications.
S10.10 End fitting corrosion resistance test. Conduct the test
specified in S6.9 using a vacuum brake hose assembly.
S11. Test conditions. Each hose assembly or appropriate part thereof
shall be able to meet the requirements of S5., S7., and S9. under
the following conditions.
S11.1 The temperature of the testing room is 75 deg.F.
S11.2 Except for S6.6, S8.2, and S10.2, the test samples are stabilized
at test room temperature prior to testing. S11.3 The brake hoses
and brake hose assemblies are at least 24 hours old, and unused.
|