MIL-PRF-87961 Hose And Hose Assemblies, Air Duct, Air Breathing, Oxygen SystemThis specification covers the requirements for hose and hose assemblies \(see 6.9\) which supply breathing oxygen to aircrews during the operation of high performance aircraft.

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MIL-PRF-87961B

4.6.5 Delamination. With one end of the hose capped, a vacuum equivalent to 16 inches

of mercury shall be applied to the hose for 10 minutes. After this period and while the vacuum is

maintained, the inner layer of the hose shall show no evidence of delamination (see 6.8).

4.6.6 Elongation. The hose shall be suspended vertically by one end and a 10 pound

load shall be applied for 30 seconds. The hose elongation shall be between 3% and 10% of the

original length. Two minutes after removal of the load, the hose shall have no permanent set in

excess of 5% of the original length.

4.6.7 Leakage. The hose shall be pressurized to 10 psig for 1 minute and then the

pressure shall be maintained at 5 psig for 5 minutes. During this time, the hose shall not leak in

excess of 0.25 cm3 per minute per foot of hose.

4.6.8 Tensile load. With a MS22058 connector attached to one end of the hose assembly

with a NAS397 clamp, a tensile load 0f 40 pounds shall be applied to the other end cover for 1

minute. The hose, end cover, or MS22058 connector shall not separate.

4.6.9 Static load. A static load of 125 pounds shall be applied for 30 seconds to a 4 inch

section of the reinforced portion of the hose, and this load shall be normal to the longitudinal

axis. With the load applied, the outside diameter shall not be reduced more than 15 percent. Two

minutes after the load is removed, the permanent set of the outside diameter shall be no more

than 5 percent.

4.6.10 High temperature. The hose shall be exposed to 160o +5oF for 48 hours. While at

160oF, the hose shall be subjected to the flexibility test. After returning to room temperature, the

hose shall be subjected to the odor, delamination, elongation, and leakage tests.

4.6.11 Low temperature. The hose shall be exposed to -40o +5oF for 30 minutes, and

then subjected to 5 cycles of the flexibility endurance test. After returning to room temperature,

the hose shall be subjected to delamination, and leakage tests.

4.6.12 Abrasion test. Two samples of the reinforced section of the hose shall be

subjected to the test in FED-STD-191, Method 5308, dry conditions. The abradant shall conform

to PIA-C-419, Type I, hard texture duck No. 10. A minimum 1 pound load shall be maintained

between the abradant and hose throughout the test. The reinforced section of the hose shall be

subjected to 10,000 horizontal motions along the longitudinal hose axis without exposing the

hose reinforcement.

4.6.13 Flexibility endurance. The hose shall be subjected to 500 cycles of being coiled

and released around a 1.75 inch diameter rod. Then with one end of the hose fixed, the other

hose end shall be subjected to 500 cycles of being twisted 270o in both directions. The hose shall

then be subjected to the delamination and leakage tests.

4.6.14 Burst pressure. The hose shall be subjected to an internal pressure of 20 psi for 5

minutes. The hose shall then be subjected to the flexibility, delamination, and leakage tests.