Replace frangible disks on the storage tanks once every 5 years. Maintain refrigeration equipment according to the manufacturer's instructions.

Halogenated Systems

Follow these procedures to test halogenated systems. Weekly: check to see that all nozzles are clear, positioned properly, and all operating controls are set properly. Semiannually: check weight and pressure containers. (See procedures for verifying CO 2 cylinders.) If the container has a loss in net weight of more than 5 percent or a loss in pressure (after adjusting for temperature) of more than 10 percent, you must either refill or replace the container. When a factory-charged nonrefillable container does not have a pressure indicator that shows a loss in net weight of more than 5 percent, you must replace the container. Annually: test all actuating and operating devices. Use a cylinder containing carbon dioxide in the place of a halon cylinder or perform a simulated test of pressure-operated devices. If release devices or aux Alarm Systems You should perform tests and maintenance of detectors, circuits, control units, annunciators, relays, and power supplies, as described in Maintenance of Fire Protection Systems, NAVFAC MO-117, chapter 3,. Some additional steps are required to test cross-zoned detectors, electrically operated releases for gaseous agents, and an abort feature.

Release Devices and Auxiliary Functions

Test electrically operated release devices for gaseous extinguishing systems annually. Combine this test with tests of detectors and the total alarm system. If you cannot perform an actual discharge test, be sure to prevent gas discharge and computer power shutdown, if provided, while observing electrical functions. This may require valve closure or partial disassembly of diaphragm piercing, solenoid plunger-type valves, and manual override of the computer shutdown feature. Refer to system instructions from the equipment manufacturer or installing company. The same method, once determined, is normally used for testing manual devices connected electrically to cause direct actuation of gas release devices. After taking necessary steps to prevent gaseous discharge, you should cause the necessary alarm conditions to activate the extinguishing system by actuating the detectors or manual initiating devices. At the end of the time delay intend, release device actuation should be evident. Verify that relays for auxiliary functions actuate. Take notes on which event relays actuate at the first cross-zoned detector alarm, second cross-zoned detector alarm, and at the end of the timer intend. Note the amount of time delay between the second detector actuation and the delayed functions.

If release devices or auxiliary functions fail, you should replace the control unit in the alarm condition and check appropriate output voltages at the control unit and at the failed device. If voltages are improper, troubleshoot the control unit or circuit as indicated. Cross-zoned systems require an alarm condition on both initiating circuits to actuate release devices and some auxiliary functions. If a timed fiction fails, check input voltage to the timer and the delayed output voltage from the timer with a voltmeter. Replace the timer if input is proper but output is not. If voltages are proper, check solenoid and relay coil continuities with one side of their respective energizing circuits open to the control unit. (See testing and maintenance for foam systems, Maintenance of Fire Protection systems, NAVFAC MO-117, section 7.3.1.) Replace defective devices and/or wiring.

Abort Feature

In gaseous extinguishing systems with an abort feature, test the feature annually along with the other elements of the system. To test the abort feature, first determine the timer setting from prior test records or installation data. Then cause first and second cross-zoned detect or alarms. The second detector alarm starts the timed period during which the gaseous agent release and other abortable functions may be activated. Operate the abort switch approximately in the middle of the time interval. Perform this test with the agent release and computer shutdown features disabled. At the end of the time interval, confirm that the aborted functions do not occur. Possible causes of abort failure are as follows:

a defective abort switch,