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 hydraulicallycontrolled 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.

The thermopneumatic elements, which monitor the temperature of the magazine and activate the sprinkler system, generate a pneumatic signal in response to thermal action. The pneumatic signal can be either a sudden increase or decrease in air pressure, which will actuate the sprinkler system.

The automatic control system consists of fixed-temperature units (FTUs), heat-actuated devices (HADs) heat-sensing devices (HSDs), transmission lines (RockbestosTM-covered copper tubing), circle seal check valves, and a pneumatically released pilot (PRP) valve. Manual control valves located at separate local and remote control stations are used to activate the system manually.

Wet-Type Sprinkler System

A wet-type sprinkler system is one in which the piping between the outlet side of the main sprinkler valve and the sprinkler heads is charged with fresh water. Once the system is activated, the fresh water is immediately discharged and replaced by salt water. Although wet-type sprinkler systems do contain quite a few more components than dry-type systems, they function on similar principles. The main advantage of wet systems is a very rapid response time. Sprinkling starts approximately 1 second after activation.

For technical operating information on both types of sprinkler systems, refer to the instruction book, NAVSEA 0348-LP-078-1000, Magazine Sprinkler System.

Q8. What are the five major types of shipboard magazines?

Q9. What type of ammunition stowage spaces are frequently located on ship's weather decks? QIO. What alarm circuit is known as the "high-temperature alarm"?

QI1. What alarm circuit is known as the "magazine sprinkler alarm"?

Q12. Under normal conditions, how often should you take magazine temperature readings?

Q13. How should magazine temperatures that are in excess of 100 F be recorded in the permanent temperature log?

Q14. What does an "AMMUNITION FAR SIDE" sign look like?

QI5. What are the two basic types of hydraulically-controlled sprinkler systems?

Q16. Which type of sprinkler system uses fresh water to charge the piping between the outlet side of the main sprinkler valve and the sprinkler heads?

SUMMARY

You have an important responsibility to handle, ship, and stow ammunition and explosives safely. Remember, the safety precautions and instructions pertaining to the safe operation and use of ammunition and explosives handling equipment must be strictly observed by all naval activities afloat and ashore. The task of ammunition and explosives handling is enormous and, by nature, inescapably hazardous. Mishaps arising in ammunition and explosives handling can kill and injure personnel, destroy essential supplies, and damage valuable equipment and property. Many of these mishaps are caused by carelessness or unfamiliarity with the use and limitations of handling equipment, as well as relaxation or failure to observe safety precautions, orders, and regulations pertaining to the handling and stowage of ammunition and explosives. You can prevent the mishaps that are caused by misuse of handling equipment if you take the time to understand the use and limitations of the handling equipment. Safety precautions and instructions are a vital element of safe ammunition and explosives handling operations. Give them careful and constant study.

ANSWERS TO CHAPTER QUESTIONS

AI.     To warn personnel of hazards that can cause personal injury.

A2. To draw attention to situations that may be potentially damaging to equipment.

A3. To ensure that each person is qualified and certified before performing any task involving explosives.

A4.     The type commander.

A5.     For a maximum of 12 months, unless it is revoked for cause.

A6.     A logistics movement.

A7. NAVSEA SWO20-AC-SAF-010, Volume I and Volume 2, Transportation and Storage Data for Ammunition, Explosives and Related Hazardous Materials.

A8. Primary magazines, missile magazines, ready-service magazines, lockers and chemical magazines.

A9. Lockers.

A10. The F alarm circuit. All. The FH alarm circuit.

A12. Once a day.

A13. In a conspicuous manner (red ink).

A14.    The sign is a yellow rectangle, 5 inches high by 9 inches wide. Painted on the sign are black slanted lines, 118-inch thick and one-inch long, on 3/4-inch centers along the top and bottom edges, with lines slanting from top right to bottom left. The letters are I/8-inch thick and 3/4-inch high.

A15.    The dry-type and the wet-type.

A16.    The dry-type sprinkler system.