properly set on watertight closures and that the space is
locked with an adequate locking device.
Only authorized personnel are be permitted in a
magazine and then only when they have business there.
A magazine is no place in which to sit and shoot the
Some ammunition and explosive items such as
small arms ammunition, small arms, and pyrotechnics
are considered to be highly pilferable and must be
stowed only in high-security stowage spaces.
Additional information on magazine security is
contained in OPNAVINST 5530.13, Physical Security
Instructions for Sensitive Conventional Arms,
Ammunition, and Explosives.
There is one more aspect of ammunition stowage
that we need to discuss. This is the magazine sprinkler
systems used for emergency cooling and fire fighting
on board ship.
Sprinkler systems provide emergency cooling and
fire fighting capability in magazines, ready-service
rooms, and ammunition handling areas. A magazine
sprinkler system consists of a network of pipes secured
to the overhead and connected by a sprinkler system
control valve to the ships saltwater fire main. The
pipes are fitted with spray heads or sprinkler head
valves arranged so that the water forced through them
showers all parts of the magazine or ammunition
handling area. Magazine sprinkler systems are capable
of completely flooding their designated spaces. To
prevent unnecessary flooding of adjacent areas, all
compartments equipped with sprinkler systems are
The fire main pressure on most ships is
considerably higher than the pressure that magazine
bulkheads can withstand; therefore, magazines are
equipped with exhaust ventilators located in the
bulkhead near the overhead. An exhaust ventilator is a
pipe with a check valve that permits pressure release
(usually to the topside). The diameter of the pipe is
large enough to allow water to flow out as fast as it
flows in. This prevents excess pressure from building
up in the magazine compartment. On newer ships,
magazines are also equipped with capped drainpipes
located in the bulkhead near the deck. The caps may be
removed in the adjacent compartment to drain the
There are two basic types of hydraulically-
controlled sprinkler systems; the dry-type and the
Dry-Type Sprinkler System
A dry-type sprinkler system is one in which the
piping from the outlet side of the main sprinkler
control valve up to the sprinkler heads contains no
water in a normal or ready state. This piping remains
dry until the system is activated. The sprinkler
system may be activated automatically or manually.
An automatic system is designed to actuate the
magazine sprinkler in response to either a rapid rise in
temperature or a slow rise to a fixed temperature.
Figure 5-7. AMMUNITION FAR SIDE, sign or label (example).