MIL-DTL-83054C
4.6.18.3 Immersion at 160°F. The baffle material shall be immersed in pure distilled water at 160°
+5°F (71.1° +2.8°C). Types I, II, and III baffle material shall be immersed for 6 weeks (or failure) and
testing frequency shall be at 2 week intervals until failure. Types IV and V baffle material shall be
immersed for 24 weeks (or failure) and testing frequency shall be a 4 week intervals until failure. Three
specimens shall be tested for each sampling frequency. Testing shall be conducted in loosely capped
jars using 900 +25 mls of water for each nine tension specimens.
4.6.18.4 Dry heat exposure. The baffle material shall be exposed to dry heat at 250° +5°F (121.1°
+2.8°C). Baffle material shall be exposed for 8 weeks and testing frequency shall be at 2 week
intervals. A minimum of two tension specimens shall be tested for each sampling frequency.
4.6.19 Flame arrestor tests. The flame arrestor characteristics of the baffle material shall be defined
using a small scale flame tube type apparatus having a minimum total volume of 5 cubic feet and a 100
square inch cross sectional area. The following parameters shall be satisfied in all the testing:
a. Stoichiometric propane/air mixture (4.5 to 5.2 volume percent propane) verified by bomb
sampling.
b. Spark ignition source having a minimum of 0.25 millijoules energy
c. Dry arrestor material
d. Minimum instrumentation shall include: pressure rise, combustion temperature indication, and
visual, photographic, or photocell indication of flame penetration downstream of arrestor.
e. Combustion relief area shall be 80% of cross-sectional area or greater. The material used for
the testing shall be taken from a given bun which has been sufficiently tested to establish its air
pressure drop (porosity) characteristics. The material shall always be oriented in the test apparatus
to permit flame penetration in the direction of porosity testing (direction of rise or bun height).
If possible, baffle material used shall be in the lower half of the air pressure drop range. For example
type I: 0.190 to 0.235; type II: 0.140 to 0.185; type III: 0.250 to 0.290; type IV: 0.140 to 0.185;
type V: 0.250 to 0.290 inch of water.
4.6.20 Material oversize. The material shall always be slightly oversized, 2% maximum when installed
and restraints used to avoid arrestor movement during testing. The combustible mixture on each test
shall be verified by bomb sampling and shall meet the minimum criteria for pressure rise, see figure 3.
4.6.21 Testing. The following testing shall be conducted and all data results shall be reported for each
test condition (see figure3 for typical flame arrestor apparatus):
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