MIL-DTL-17902G(SH)
4.5.3 Resistance to vacuum (type NC only).
4.5.3.1 Initial. Each of the sample hose assemblies selected in accordance with table X shall be subjected to a
vacuum equivalent to a 22-inch height of Hg for a period of not less than 5 minutes. The hose shall not collapse or
otherwise deform more than 15 percent of original diameter. The decreases in diameter of the hose where
deformation occurs shall be measured in accordance with ASTM D380.
4.5.3.2 After holding test fluid. A 5-foot length shall be cut from the sample hose assembly submitted in
accordance with table X, note 2a. One end shall be plugged and the hose filled with Reference Fuel B of
ASTM D471. The other end shall then be closed and the hose let stand for 46 hours at a temperature of 70 to
80 degrees Fahrenheit (°F). At the end of this period, the fluid shall be drained from the hose. Within 5 minutes
after removal of the fluid, the hose length shall be bent to a radius of 15 inches for the 1½-inch id hose, or 18 inches
for the 2½-inch id hose. The bent hose length shall then be subjected to a vacuum equivalent to a 22-inch height of
Hg for a period of not less than 15 minutes. The decrease in diameter of the hose where deformation occurs shall be
measured. After release of the vacuum, the hose shall be dissected longitudinally and examined for evidence of
failure by ply separation, blistering, collapse, or other damage.
4.5.4 Resistance to proof pressure. Each length of hose selected in accordance with 4.3.1 and previously used
for the vacuum test (see 4.5.3) shall be measured for length and circumference as specified in ASTM D380. Each
hose shall then be subjected to a hydrostatic test to the proof pressure in accordance with table VI for a period of not
less than 10 minutes. At the end of this period, while the hose is still under pressure, its length and circumference
shall again be measured, it shall be examined for leakage or other signs of weakness, and the contact assembly shall
be checked electrically to assure that there is no electrical contact between the couplings and intercontrol cable.
4.5.5 Resistance to burst. A 3-foot length shall be cut from the sample hose selected in accordance with
table X, note 2a. Couplings shall be attached to the 3-foot length and the ends blanked off. The hose shall then be
subjected to increasing hydrostatic pressure to the pressure stated in table VI with the rate of pressure rise not
exceeding 100 psi per minute. The pressure at which leakage occurs shall be noted.
4.5.6 Low temperature flexibility. A 4-foot length shall be cut from the sample hose submitted in accordance
with table X. One end shall be plugged and the length filled with Reference Fuel B of ASTM D471. The other end
of hose shall then be plugged, and the hose exposed to a temperature of -22±2 °F for 24 hours while held straight.
At the end of this period and while at -22 °F, the hose shall be bent 90 degrees around a mandrel 30 inches in
diameter within 4 seconds. The fluid shall be drained from the hose, and the hose cut in half longitudinally. The
tube and cover shall be examined for cracks or other damage.
4.5.7 Cleanliness test.
4.5.7.1 Specimen. A 4-foot length shall be cut from the sample hose submitted in accordance with table X.
Extraneous dust or other contaminants shall not enter the hose tube. The hose shall be closed with clean plugs at
each end. Each plug shall have an outlet hole connected via a pipe nipple to a valve. The interiors of the pipe
nipples and valves shall be carefully cleaned prior to use.
4.5.7.2 Apparatus. A machine is required that will impart a rotary motion in a vertical plane to a rigid bar that
is attached at its center to a horizontal axle driven at 12±1 revolutions per minute (rpm). Four adjustable band
clamps shall be attached symmetrically to the rigid bar to hold the specimen firmly.
4.5.7.3 Procedure. The specimen, having been sealed at one end by a prepared plug, shall be filled with
Reference Fuel B of ASTM D471 and hung vertically for 16 to 24 hours. The fluid shall then be drained from the
specimen and 2 liters of fresh medium number 6 added, and the open end plugged. The specimen shall then be
clamped securely to the rotating bar so that the ends are spaced evenly from its center. After 120 minutes of rotary
motion at 12 rpm at 70 to 80 °F, the first liter of the fluid shall be withdrawn for analysis. The amount of sediment
shall be determined in milligrams per liter in accordance with ASTM D2276 using a 0.8-micrometer pore filter. The
tests shall be performed in duplicate and the results averaged. A control analysis shall determine the amount of
contaminant present per liter in the medium number 6 used for the test. The average amount of sediment found i n
the specimen shall be reduced by the amount found present in the control, and the difference recorded as the amount
of particulate contaminant in the hose.
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