motors burn, they rapidly produce large volumes of
smoke and gas. To avoid spreading smoke and gas to
other areas of the ship if a missile motor in a magazine
accidentally ignites, the exhaust ducts are vented to the
atmosphere. The area on the weather deck in the
vicinity of an exhaust vent is potentially hazardous, and
it is marked to warn personnel not to loiter (hang
around) in this area.
SPRINKLER AND ALARM SYSTEMS
handling rooms and most ready-service magazines are
fitted with sprinkler systems. Sprinkler systems consist
of spray heads or sprinkler-head valves arranged to
dash water directly on the munitions and completely
cover the magazine's interior. Sprinkler systems for
spaces located below the damage control deck (second
deck on aircraft carriers) are arranged for local control
at the valve and for remote control from the damage
control deck. On aircraft carriers, the remote controls
are normally divided into two groupsforward
sprinkler control board and aft sprinkler control board.
The forward magazine group and the aft magazine
group sprinklers can be remotely activated from the two
control boards. Sprinkler systems for spaces located on
and above the damage control deck are arranged for
local control only from a position outside the access
entrance to the space.
NOTE: Some magazines are designed without
ammunition can be stowed in them. For
example, Mk 58 marine location markers
cannot be stowed in magazines that can be
20-mm and 40-mm ready-service rooms do not
require sprinkler systems.
Sprinkler systems are classified by the type or
location of the control exercised over the valves that
restrain the flow of water. These valves may be
operated manually or by remote control (manually or
automatically). There are three types of remote
Manual, by operating gears
Hydraulic, by means of control cocks and
water from the fire system or control cocks and
oil pressure supplied by hand pumps
Automatic, by means of a rate of rise or
combined rate of rise and fixed temperature
thermopneumatic control system
The rate of rise is indicated in a magazine when the
temperature increases rapidly (such as from a fire). The
rapid temperature increase activates the sprinkler-alarm
device (FH circuit), which, in turn, automatically
activates the sprinkler system control valve.
There are three alarms that are commonly
associated with all magazine sprinkler systemsa
sprinkling (FH circuit) alarm, a flooding (FD circuit)
alarm, and a high-temperature (F circuit) alarm.
High-temperature alarm systems (F circuit) are
installed in all of the following magazines or
Ammunition and propellant stowage areas
Ammunition handling spaces
Cargo ammunition holds to provide a means of
determining high temperatures
Don't confuse the F circuit with the FH circuit. The
F circuit detects a slow rise in temperature while the FH
circuit detects a rapid rise in temperature.
Install a minimum of two thermostats in each
space. Install a minimum of one thermostat for each
250 square feet of deck area, or fraction of a deck area.
If high temperatures occur in any of the spaces
containing thermostats, the high-temperature that
occurrence is indicated on an alarm switchboard
installed in an area continuously manned when the ship
is underway. Usually, this is damage control central.
Audible alarm systems are also installed in the
pilothouse, officer-of-the-deck (OOD) area, secondary
communications room. The audible alarm systems
work in conjunction with the F and FH circuits.
Tests and maintenance of the magazine sprinkler
systems are performed periodically according to
NAVSEA and applicable preventive maintenance
system (PMS) instructions.
MAGAZINE INTERNAL ARRANGEMENT
The internal arrangement of each magazine may
vary considerably. The arrangement depends on the