3. Protect electrodes from ice. If ice formation is a serious problem, turn off current and remove and store the electrodes during the freezing season. Tank protection will continue for about 3 weeks after the unit is out of operation. Reinstall the electrodes at the end of the freezing season.

Nonfreeze Systems

No special testing of nonfreeze systems is required, other than an annual check of the specific gravity of the non freeze solution. If the specific gravity indicates a need for replenishing the nonfreeze agent, be sure to add the same agent as was previously used.

High-Speed Suppression Systems

Full operational testing of high-speed suppression systems is conducted at intervals not to exceed 3 years except when mission requirements justify change. A detector or a manual release station must be actuated. Check to be certain that all nozzles are operating. Then, follow these steps to reset the system:

1. Replace pre-prime caps and/or rupture disks.

2. Refill piping with water.

3. If the system uses an explosive valve, replace the firing squib and the squib holder.

MAINTENANCE REQUIREMENTS

The need for maintenance is shown by periodic inspections. It should include replacement of worn or broken components and cleaning and flushing of systems. A regular schedule of maintenance requirements should be devised. Logs recording accomplished tasks should be maintained as a record of the system's history. Be sure to include manufacturers' manuals for the system components and consult them when making repairs and adjusting or troubleshooting the system.

GASEOUS EXTINGUISHING SYSTEMS

Gaseous extinguishing systems are generally found in areas where equipment is installed that would be highly vulnerable to destruction from water or dry chemical extinguishing agents. Computer rooms, electronic gear such as radio receiving and transmitting equipment, and power generating facilities are examples of areas where gaseous extinguishing system installation would be desirable. In the Navy today, the Utilitiesman will come in contact with two commonly used systems. These are the carbon dioxide and the halogenated gas systems. Each of these systems is discussed in this section.

Gaseous extinguishing systems can be divided into three general categories: local application, total flooding, and hose line systems. Local application systerms discharge agent onto the burning material and are commonly used for protection of paint dip tanks, restaurant range hoods, and special motors. Total flooding systems discharge agent into and fill enclosed space. They are commonly found in flammable liquid storage rooms, computer installations, and transformer vaults containing oil-filled equipment. Hose line systems discharge extinguishing agent through manually operated nozzles connected to a fixed supply by piping and/or hoses. At present, carbon dioxide is the only gaseous agent approved for manual hose line systems.

CARBON DIOXIDE SYSTEMS

Here are two general methods of applying carbon dioxide to extinguish a fire. One method creates an inert atmosphere in the enclosure or room where the fire is located for a prolonged period of time. This method is called total flooding. The second method is to discharge carbon dioxide to the surface of liquids or noncombustible surfaces coated with liquid flammables. This method is known as local application.

Carbon dioxide is electrically nonconductive. It is used extensively for the protection of

Figure 8-30. - Typical cylinder arrangement for high-pressure CO2 system.