Fuel
Systems
Appendix A — Fuel System Standard
16.0 — Lab Examination No. 12
Fuel Tank Shock Test cont'd
16.3 Test
16.3.1 This procedure shall
be used to shock test metallic and non-metallic fuel tanks
of any size and capacity. Fuel tanks which have a capacity
of 25-gal. (94.6 l) or larger shall not be tested.
Verify the applicability of this procedure to
the tank being tested before proceeding by filling the tank
to its maximum capacity.
16.3.2 Visually inspect the
fuel tank. Review the results of the Receiving Inspection
(Data Form No. 1) and verify that the component is acceptable
and ready for testing. Tanks that obviously would leak and
have failed the pressure test, or those that do not have a
proper label shall be rejected.
16.3.3 Verify that the fuel
tank to be tested has successfully completed the static pressure
test. If it has not been accomplished, the pressure test shall
be completed at this time. Record whether the pressure was
accomplished previously or is being completed at this time.
16.3.4 Non-metallic fuel tanks
shall be filled to capacity with a gasoline that has at least
a 50% aromatic content. ASTM Reference Fuel C meets this requirement.
There shall be no evidence that the fuel tank has been adversely
affected by the gasoline after 30 days at ambient pressure
and temperature, but in no case less than a temperature of
70°F (21°C).
FIGURE:
Shock Test — Typical Layout for Flat-Bottomed Tank
Test Schematic Procedure
FIGURE:
Shock Test — Typical Layout for Non-Flat-Bottomed Tank
Test Schematic Procedure
16.3.5 Flush or purge the fuel
tank with water and/or GN2 after the 30-day pre-conditioning
test has been completed.
16.3.6 Verify that the shock
machine to be used in this test has been calibrated to the
specified g load and duration using a dummy load similar to
the fuel tank to be tested.
16.3.7 Mount and secure the
fuel tank to the platform of the impact test machine similar
to an actual installation or similar to one of the following
typical installations. Do not remove any attachments or fittings
from the tank. Flat-bottomed tanks shall be mounted on a flat
platform. Tanks with other than flat bottoms shall be mounted
on chocks cut to fit under the ends of the tank and under
the baffles, if any. See the Test Schematic for typical installations.
16.3.8 Fill in the tank with
water to at least rated capacity. Cap and/or plug the fuel
tank fill pipe and the fuel feed adapter. If a gasoline gauge
is not installed, cap this opening. Leave the fuel tank vent
pipe open to the atmosphere.
16.3.9 Fuel tanks installed
in the forward half-length of the boat or labeled or intended
for use in the forward half-length of the boat shall be subjected
to 1000 cycles of 25 g vertical shock. Fuel tanks installed
in the aft half-length of the boat or labeled or intended
for use in the aft half-length of the boat shall be subjected
to 1000 cycles of 15 g vertical shock. When in doubt about
a fuel tank’s installation or usage, subject the tank
to 1000 cycles of 25 g vertical shock. The duration of the
shock pulse, measured at the base of the shock envelope, shall
be 10 ±4 milliseconds. The shock shall be applied at
a rate of 80 cycles or less per minute. The test parameters
shall be monitored by suitable instrumentation mounted as
near to the center of gravity of the fuel tank as possible.
16.3.10 The fuel tank shall
be visually inspected after wach shock test has been applied.
If any obvious failure has occurred, the fuel tank shall be
rejected.
16.3.11 If the tank shows no
indication of any leakage after 1000 shock applications, remove
the tank from the shock machine and secure the system.
16.3.12 Perform the pressure
test on the fuel tank and verify that the tank does not leak.
If leakage is found during the test, the tank shall be rejected.
If the tank successfully completes the pressure test, the
tank shall be deemed acceptable according to the requirements
of this procedure.
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