SPRINKLER SYSTEMS

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 breeze.” 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 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 ship’s 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 watertight. 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 flooded magazine. There are two basic types of hydraulically- controlled sprinkler systems; the dry-type and the wet-type. 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. 5-16 YELLOW BLACK 1 IN. 9 IN. 5 IN. FAR SIDE 1/8 IN. 3/4 IN. AMMUNITION FCf05007 Figure 5-7.— AMMUNITION FAR SIDE, sign or label (example).