TM 5-822-5/AFM 88-7, Chap. 1
APPENDIX C
METHOD OF TEST FOR PREFORMED POLYCHLOROPRENE
ELASTOMERIC JOINT SEAL JET-FUEL-RESISTANCE
of test fuel. Several specimens of the same material
C-1 Scope.
may be immersed in the same container provided
This test method provides a procedure for
each test specimen is separated from any adjacent
evaluating the ability of preformed polychloroprene
test specimen and container walls by a minimum of
elastomeric (PPE) joint seals to withstand the
6 millimeter and the minimum fuel cover is
effects of jet fuel. The effect of fuel is determined
maintained. A constant temperature water bath shall
by noting the change in weight of the seal before
be used to maintain the test fuel and specimens at
the 491ECelsius (120EFahrenheit) for 24 hours.
and after immersion in a test fuel.
Immediately after the 24 hour fuel immersion, the
specimens shall be removed from the test fuel and
C-2. Preparation of Specimens.
dried in a forced draft oven at 701ECelsius
(1582EFahrenheit for 240.25 hours. The forced
Compliance with the change in weight requirement
shall be determined by tests conducted in ac-
air shall be maintained at an air velocity of 150 to
cordance with the methods specified using speci-
500 feet per minute. After oven drying, the speci-
mens cut from manufactured seals. Three specimens
men shall be allowed to cool for 30 minutes at room
shall be tested for each lot of batch or seal
temperature and than weighed to the nearest 0.01
submitted for testing. Each specimen shall be rec-
gram.
tangular having dimensions of 60+1 millimeter by
20+1millimeter by 2+0.1 millimeter. Specimens
C-4. Calculations
shall be the thickness of the seal as received when
they are less than 2 millimeter thick; otherwise the
The change in weight shall be calculated as fol-
specimens shall be buffed to a thickness of 2+0.1
lows--
millimeter.
W1 & W2
Change in weight, percent '
100
W1K
C-3. Test Procedures.
Each test specimen shall be weighed to the nearest
0.01 gram and then immersed for 24+0.25 hours in
where
clean test fuel maintained at 49ECelsius
W1 = initial specimen weight
(1202EFahrenheit). The specimens shall be sus-
W2 = final weight after immersion and oven drying
pended in the test fuel so that the bottoms of the
test specimen are a minimum of 12 millimeter above
The average of three specimens shall be reported as
the container bottom, and there is a minimum of 12
the percent change in weight.
millimeter of test fuel over the tops of the
specimens. The container for the test fuel and
C-5. Requirement.
specimens shall be semiclosed to reduce fuel evap-
oration and eliminate pressure buildup. The overall
When tested as specified herein, the PPE joint seal
dimension of the container shall be deep enough to
material shall have an average change in weight on
allow the test specimens to be suspended by wire or
exposure to fuel of 25 percent or less.
string and covered with not less than 12 millimeter
C-1
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