MIL-DTL-13531J
4.8 Methods of inspection.
4.8.1 Test methods. The following identified tests and test methods assure hose and hose assembly
integrity within typical operating conditions and applications. Alternate commercial industry standard test
methods are allowed; however when an alternate method is used, documented approval must be
obtained from the qualifying activity prior to the performance of the test. The test methods described
herein are proven methods and shall be the referee method in case of dispute.
verify that the design, construction and physical dimensions are in accordance with the applicable
requirements.
4.8.3 Resistance to impulse pressure (see 3.6.1). Hose assemblies when tested in accordance with
SAE-AS603 shall meet the requirements of 3.6.1. The following details shall apply:
a. Test specimens shall consist of two hose assemblies, each with a free length between fittings
b. To determine conformance to 3.6.1, test each specimen as specified:
(1) 3/4 inch (.75 inch) (19.05 mm) inside diameter or less shall be mounted on the impulse
test machine in a "U" shape with a bend radius as specified in table table III.
(2) Each hose assembly of 7/8 inch (.875 inch) (22.23 mm) inside diameter or larger shall be
straight when mounted on the impulse test machine.
c. One end of each test specimen shall be connected to a rigid support and the other end to a
non-rigid support to allow for specimen contraction in length.
d. Hydraulic fluid conforming to MIL-PRF-5606, MIL-PRF-6083 or MIL-PRF-83282, maintained at
a temperature of + 120°F ±10°F (49°C ± 5.56°C) shall be used as the impulse medium and
shall circulate through the hose during the test.
e. Each impulse cycle shall consist of:
(1) Pressure rises from 0 to a peak of 125% ± 5% of the working pressures listed in table II
then levels off to 100%. Hoses larger than one inch ID type I hoses shall be 100% of the
working pressure specified in table II.
(2) Followed by a pressure drop to 0 psi in accordance with SAE-AS603.
(3) Tolerance plus 150 psi, minus 0 psi (+10 bar, -0 bar).
f. The working pressures for each respective hose sizes are specified in table II except the
maximum impulse pressure shall not exceed 3,750 psi (258.55 bar) for type I or 5000 psi
(344.74 bar) for type II or III. The shape of the pressure-time curve shall fall within the shaded
area shown on figure 1.
g. Cycles shall occur at the rate of 35 ± 5 cycles per minute.
h. The number of impulse cycles shall be 150,000 for type I hoses and 200,000 for type II and III
hoses.
i. Nonconformance to 3.6.1 shall constitute failure of this test.
4.8.4 Length change (see 3.6.2). Hose assemblies when subjected to the length change test in
accordance with ASTM D380 shall meet the requirements of 3.6.2. The following details shall apply:
a. Test specimens shall consist of three hose assemblies, each not less than 12 inches
(304.8 mm) between fittings.
b. Final pressure shall be the working pressure specified in table II for the type and size hose
tested.
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