Missile  magazines  contain  special  features  to combat  the  effects  of  accidentally  ignited  rocket motors.  Restraining  latches  (e.g.,  cell  latches)  keep each missile from moving in the magazine. Blowout hatches, relief ports, and plenum exhaust vents pass rocket motor gases to the atmosphere. This prevents internal  magazine  pressures  from  building  to dangerous levels. Missile  magazines  are  normally  equipped  with special  combustion  detection  devices  and  contain automatic  sprinkler  systems,  with  remote  and  local activation capabilities. Missile magazines also have a water  injection  or  booster  suppression  system.  A carbon  dioxide  system  may  be  installed  in  some magazines,  especially  in  unmanned  spaces.  Missile magazines  are  insulated,  have  temperature  control systems,  and  must  be  closed  and  locked  when unattended. Ready-Service Magazines Ready-service  magazines  are  located  near  the missile launcher they serve. They provide permanent stowage for part of the ship’s ammunition allowance, especially   gun-type   ammunition.   Generally, ready-service  magazines  have  many  of  the  same characteristics  as  primary  magazines.  They  are insulated,  ventilated,  and  have  manually  activated sprinkler systems. Missile  magazines,  although  in  a  class  by themselves,   are   sometimes   considered   as ready-service  magazines.  Ready-service  magazines must be closed and locked when unattended. Lockers A  locker  can  be  a  small  compartment  or  space. More  often  though,  a  locker  is  a  metal  box-like structure. In either case, a locker provides stowage for special  types  of  ammunition  such  as  detonators  and pyrotechnic devices. Lockers are frequently located on a ship’s weather deck. They will be close to the weapon or area they are intended to serve. A label installed on the outside of each  locker  clearly  identifies  the  type  of  explosives contained within the locker. The contents of a locker must be arranged in a neat and orderly manner. When the locker’s lid or door is closed,  it  cannot  contact  (or  jam)  any  part  of  the ammunition. Securing and safety latches, hinges, and other hardware must be well-maintained and in good working condition. Sometimes, lockers are equipped with a sprinkler or flooding system. If such a system is installed, clear and legible operating instructions must be prominently displayed. Lockers must be kept closed and locked when unattended. ENVIRONMENTAL CONTROLS Magazines   are   fitted   with   appropriate environmental  control  and  safety  features  to  protect their  ammunition  from  excessive  temperatures  and humidity. Most  magazines  are  equipped  with  mechanical cooling or ventilation systems. However, there are a few magazines that do not have either of these features. If a magazine without controls shows a heat gain in excess of 100 F, portable ventilation systems are used to prevent overheating or condensation of moisture. Supply and Exhaust Ventilation Ventilation ducts and exhaust ventilation outlets to and from magazines provide forced-air ventilation. Air is forced through the ducts by electric fans installed within  the  ducting.  Standard  covers  maintain water-tightness keep flames caused by hits on the ship during  combat  from  entering  the  magazines.  These covers must always be closed during combat (general quarters)  conditions  unless  there  are  imperative reasons for doing otherwise. Certain types of ammunition may produce fumes that, if inhaled, may have a slightly intoxicating effect. However,  this  should  not  appreciably  reduce individuals’  work  efficiency.  Generally,  there  is sufficient  air  volume  in  large  sealed  magazines  and handling rooms to provide a safe working atmosphere. Frequently,  in  hot  climates,  magazines  can  be maintained at a lower average temperature by closing off  the  supply  of  air  during  the  heat  of  the  day  and running the blowers only at night when cool air can be forced in. During the day the magazine will heat slowly by conduction rather than rapidly by the introduction of heated air. Magazine Vent Check Valves It may be necessary to operate the sprinkler system in magazines while the ventilation valves are secured. During these times; the magazine must be vented by an air  escape  to  ensure  that  the  pressure  within  the magazine  will  not  build  up  beyond  the  allowed pressure limits of the watertight boundaries. Magazine 5-12