Another type of alarm is the flooding alarm, designated
FD, that incorporates a float switch located near the
deck. As water accumulates on the deck, the float rises,
making a set of contacts and sounding an alarm. If the
sprinkler system is actually activated, both alarms
should sound within seconds of each other.
Another type of alarm system, designated the F
alarm, is actuated by heat. This alarm sounds when the
temperature in an ammunition stowage area rises to
105F. The sounding of this alarm allows the
temperature to be reduced before sprinkling becomes
necessary.
Figure 1-13.--Test casting installed in a magazine sprinkler
control valve.
SYSTEM TESTING
The test casting is simply a bypass attachment that
Each sprinkling system must be tested regularly to
allows system water to flow out of the bottom of the
be sure that it operates properly. During the test, all
components that should operate during an actual use are
control valve, rather than through its normal exit port.
tested. This is a major test that, if not conducted
Before the control valve is tested, the bottom cap of the
properly, could cause damage to both equipment and
valve is removed and the test casting is screwed, hand
careers. Therefore, if you participate in a sprinkling
tight, into the bottom of the valve seat, as shown in
system test, follow the approved testing procedures
figure 1-13. As long as the test casting is properly
exactly. The proper officials (weapons Officer, DC
installed, no water will flow into the magazine during
Central, OOD, etc.) should have been notified, and the
the system test.
appropriate tag out procedures should have been
completed. We will not discuss the specific procedures,
If you are assigned to install a test casting, be sure to
but we do need to briefly discuss the use of the test
install the correct casting. Your ship will have the same
casting.
number of test castings as it does sprinkler system
Look back at the magazine sprinkler control valve
control valves because each valve comes from the
in figure 1-4. If the system is tested without somehow
manufacturer with its own test casting. Test castings are
blocking the flow of water through the valve, firemain
not interchangeable. When a valve is received on board
water will flow rapidly into the magazine distribution
a ship, the valve and its test casting are both stamped
piping and will probably damage the stores in the
with the same, unique number. Be sure the test casting
magazine. To allow the valve to be tested without
you install has the same identification number as the
wetting the magazine, the manufacturers of the control
valve you plan to test.
valve developed a special plug, called the test casting.
1-13
