Quantcast HSDs

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The HSDs are connected to the manifold of the PRP valve. In the event of a rapid rise in temperature, the air within the HSD expands and transmits a pressure to the rear of the PRP valve release diaphragm. In the event of a smoldering fire, a fusible link on the end of the HSD parts when the temperature in the space reaches 160F, 3F When the link parts, a spring-loaded bellows is released. The rapid compression of the bellows transmits a pressure to the rear of the PRP valve release diaphragm. In both instances a differential pressure is created to trip the PRP valve.

A differential pressure of at least 8 ounces psi across the release diaphragm is necessary to trip the PRP valve.


The gauge mounted on the front of the PRP valve indicates the pressure within the entire system-not the differential pressure. At times the gauge may indicate a positive pressure within the system. This pressure is a normal condition caused by expansion of air within the system as a result of increased ambient temperature. The pressure indicated on the gauge exists on both sides of the PRP valve release diaphragm.

For a complete operating description of all the different magazine sprinkler system configurations, refer to Magazine Sprinkler Systems, NAVSEA S9522-AA-HBK-010.


Several types of warning devices or systems are used on board ship. One of them is the alarm system activated by the water switch (fig. 2-24) on the dry side of the sprinkler system main (group) control valves. This alarm is designated FH and indicates by sound or by light when the main control valve is open or leaking. Another type of alarm is the flooding alarm, designated FD, that incorporates a float switch located near the deck. As water accumulates on the deck, the float rises, making a set of contacts and sounding an alarm. It is worth considering that, in the event the sprinkler system is actually activated, both alarms would sound within seconds of each other. Remembering this fact will help

Figure 2-24.-FH alarm sensor.

you react appropriately when you receive notification that an alarm has been triggered.

Another type of alarm system used is actuated by heat, designated F alarm. This alarm sounds when the temperature in an ammunition stowage area rises to 105F. With this warning, the temperature can be reduced before sprinkling becomes necessary,


LEARNING OBJECTIVES Identify the equipment and requirements for the safe handling and stowage of Navy ammunition. Recall the Qual/Cart program and its associated training.

The safe handling and stowage of Navy ammunition requires a high degree of knowledge and skill on the part of all involved. You will be expected to operate heavy equipment and configure ammunition for underway replenishment. You will also be responsible for training and supervising individuals serving as members of ammunition-handling work parties. In this section we will discuss the loading/offloading plan and describe some of the common handling equipment and ammunition-handling training programs. We will also identify some ammunition safety requirement publications that you should use for further study.

Before you handle any ordnance, a plan must be formulated and implemented to ensure maximum efficiency and, most importantly, the safety of the evolution. Normally, the basic guidelines for various handling operations may be found in the unit Standard Organization and Regulation Manual (SORM). However, the individual plan for each evolution should be issued as a weapons (or combat systems) department notice or instruction based on the type of operation to be performed


Before or upon arrival of a Navy ship at an explosives pier for loading or offloading of ammunition or other hazardous material, a conference should be held to coordinate safety procedures on the pier and on board ship. The commanding officer or authorized representative of the ammunition activity and the commanding officer of the ship, with other designated ships personnel, should attend the conference.


Before loading or offloading any ammunition (other than the small amounts which will be handled by qualified weapons personnel), you should outline and promulgate a workable ammunition-handling plan in the form of a weapons department notice. The ships organization manual may include a standard loading plan. If not, you can probably find a previously used plan in your weapons department files of instructions and notices. This plan can be used as a guideline but will very likely have to be altered to meet present circumstances.

Your loading plan should include the following information

1. A sketch or drawing showing the positions of all stations where ammunition will be taken aboard; and, if the ship is to be at an anchorage, the positions that all barges, camels, cranes, and associated equipment will take alongside the ship.

2. The types and amounts of ammunition to be taken aboard at each station.

3. A clear description of the route that each type of ammunition will take from the onload station to the magazine.

4. A list of personnel assigned to each station, providing for rotation, chow relief, and change of station upon completion of comparatively short assignments.

5. A list of the ammunition-handling equipment to be supplied at each station by the ship. This equipment should be thoroughly inspected before the operation.

6. A list of the ammunition-handling equipment to be supplied by the ammunition or other facility, and where the equipment will be required. This list will include such equipment as cranes, conveyor belts, bomb trucks, and electric forklifts.

7. A definition of smoking areas (if any).

8. A list of all pertinent safety precautions.

9. A list of the types and amounts of ammunition to be loaded into each separate magazine. (A loading plan for each magazine should be given to the officer or petty officer in charge of its stowing.)

Depending on the circumstances, you may find other important items to add to your loading plan. An offloading plan includes much of the same information as the loading plan, except, of course, that routings and participants might be different.

All persons in a supervisory capacity should receive a copy of this plan. If at all possible, supervising petty officers should be assigned to stations where personnel of their own division are working. This assignment will prove especially helpful should it become necessary to shift large groups to another station during the operation.


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