vessel's  complete  allowance  of  ammunition  for peacetime   operation. READY-SERVICE MAGAZINES.—Ready- service magazines are spaces physically convenient to the weapons they serve. They provide permanent stowage for part of the ammunition allowance. They are normally  equipped  with  insulation,  ventilation,  and ammunition sprinkler systems, and should be secured by locking. The combined capacities of primary and ready-service  magazines  are  normally  sufficient  to  stow properly  the  allowance  for  war  and  emergencies. READY-SERVICE STOWAGE.—Ready-service stowages are those ammunition stowage facilities in the immediate  vicinity  of  the  weapon  served.  They  include weather deck lockers, bulwark (gun shield) racks, and 5-inch  upper  handling  rooms.  This  stowage  normally  is filled only when the weapon is to be fired. There is little security for ammunition in such stowage, and it provides the  least  favorable  protection  from  the  elements. Magazine  Sprinkler  Systems As a member of a magazine crew, you may be trained to operate the magazine sprinkler systems protecting your magazine. You must be PQS qualified to operate any sprinkler system. Do not tamper with any sprinkler  system  controls  unless  you  have  been thoroughly trained, certified, and instructed to do so by competent   authority   according   to   your   ship's instructions. Sprinkler systems are used for emergency cooling of,  and  firefighting  in,  magazines,  ready-service  rooms, ammunition, and missile-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 firemain. The pipes are fitted with spray heads or sprinkler head valves that are  arranged  so  that  the  water  forced  through  them showers all parts of the magazine or ammunition and missile handling areas. A modern sprinkler system can wet down all exposed bulkheads at the rate of 2 gallons per  minute  per  square  foot  and  can  sprinkle  the  deck  area at the rate of 4 gallons per minute per square foot. Magazine sprinkler systems are designed so that they are capable of completely flooding their designated spaces within an hour. To prevent unnecessary flooding of adjacent areas, all compartments equipped with sprinkler systems are watertight. Upper deck handling and ready-service rooms are equipped with drains that limit  the  maximum  water  level  to  a  few  inches. Magazines  are  completely  enclosed;  if  flooded,  they would be exposed to the full firemain pressure. The firemain pressure on most ships is considerably higher than the pressure that magazine bulkheads could withstand;  therefore,  magazines  are  equipped  with exhaust ventilators, which are 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). Since the diameter of the pipe is large enough to allow water to flow out as fast as it flows in, no excess pressure can build up in the magazine compartment. Magazines are also equipped with small, capped drainpipes located in the bulkhead near the deck The caps may be removed in the adjacent compartment to drain  flooded  magazines. The sprinkler system control valve and associated components vary in complexity with the type of ship, type of stowage, and type of ammunition or missile stowed  in  the  magazine. PYROTECHNICS L E A R N I N G     O B J E C T I V E :     D e f i n e pyrotechnic. List and explain the different types of pyrotechnics pistols and pyrotechnics used aboard ship. Explain the storage and handling procedures  for  pyrotechnics. Pyrotechnic is the Greek word for fireworks. The Navy  uses  fireworks  not  for  celebration  but  for illumination, marking, and signaling. An example is the illuminating  projectile,  or  star  shell,  used  to  illuminate targets for gunfire. A star shell actually is a pyrotechnic device, although it is encased in a projectile body of standard external shape and is fired from a standard rifled gun. In the following sections, we discuss the common pyrotechnic devices currently in use on modern Navy surface ships. For further information on these and other pyrotechnic  devices  used  by  the  Navy,  refer  to Pyrotechnic,  Screening,  Marking,  and  Countermeasure Devices,  NAVSEA  SW050-AB-MMA-010.  All  the pyrotechnics we study here are intended for signaling and marking. We discuss the following: Marine  location  markers Marine illumination signals and the pyrotechnic pistols and projectiles used in firing them 6-8