check valves allow air and water to escape from the
magazine into one of the ventilation ducts or through
an independent air escape.
Most magazines, particularly missile magazines,
are vented to the atmosphere. When missile motors
burn, they rapidly produce large volumes of smoke and
gas. If a missile motor should accidentally ignite in a
magazine, the smoke and gas will be vented directly to
the atmosphere, rather than to other areas of the ship.
The area on the weather deck in the vicinity of an
exhaust vent is potentially hazardous and is marked to
warn personnel not to loiter in the area.
Magazines are equipped with various alarm and
sensing devices. When activated, they provide audible
and visual warnings that something is wrong. An alarm
may mean that an actual problem exists or that a
problem is developing. Designated personnel should
investigate any activated alarm immediately. The
following paragraphs discuss three common alarms.
FH ALARM CIRCUIT.The FH alarm circuit
is used with a magazines sprinkler system to indicate
two system problems: leakage and activation. Leakage
indicates that a problem is developing. Actuation
means that water is flowing and the ammunition is
getting sprayed. Actual sprinkling can result from a
real fire or a high heat buildup in the magazine. It also
can result from a gross sprinkler system malfunction.
In any case, appropriate action must be taken
F ALARM CIRCUIT.The F alarm circuit is
also known as the high-temperature alarm circuit. It
sounds an alarm when magazine space temperature
reaches a dangerous level. If the F alarm sounds, you
should investigate the problem immediately! If you
react quickly enough, you may be able to take
measures to reduce the temperature. This may prevent
the sprinkler system from activating.
DETECTOR.Some magazines may contain a
combustion gas and smoke detector. This detector is
another early warning device similar to a smoke
detector in a house. It detects the presence of
combustion gases and smoke particles in the air formed
in all types of fires and in smoldering or overheated
materials. These particles are so small that they are
invisible to the human eye; however, they are present
before there is any evidence of flame.
Aboard ship, magazine inspections are mandatory
and are an integral part of the ships PMS. These
inspections must be conducted by qualified personnel
using a check sheet (maintenance requirement card) to
ensure that a hazard or abnormal condition is not
It is not within the scope of this manual to discuss
in detail the criteria of all required magazine
inspections. However, we can provide a brief
description of daily magazine inspection
Daily Visual Inspections
The daily visual inspection of magazines generally
consists of checking for improperly secured stowage,
unsatisfactory protective packaging, unusual fumes or
odors, magazine cleanliness, and any other abnormal
Abnormal conditions in a ships magazine or
ammunition stowage space include evidence of
tampering to gain access (broken, damaged, or missing
locks), evidence of theft, and the presence of
unauthorized materials. Abnormal conditions also
include evidence of localized overheating from
adjacent compartments on decks, bulkheads, and
overheads; indications of leaks from sprinkler or flood
pipes, nozzles, or control valves and regulators; and
inoperable or damaged reachrods, linkages, automatic
fire alarm devices, and other similar equipment.
Another important requirement of the daily
inspection is to observe, record, and report maximum
and minimum temperature conditions.
Temperature is the most important factor that
affects powder and propellant stability. This is why its
important to monitor temperature conditions.
Temperature readings are normally taken once a
day. The exact time may vary, but most ships take the
readings in the morning (around 0800 for example),
using a special maximum and minimum thermometer
(sometimes called a high-low thermometer). Figure
5-5 illustrates a typical maximum and minimum