pump room safeties or alarms

As per IACS requirements:

Where alarms are fitted to caution of the release of the fire extinguishing medium into the pump-rooms, they may be of the pneumatic type or electric type.

1. Pneumatically operated alarms: In cases where the periodic testing of such alarms is required, CO2 operated alarms should not be used owing to the possibility of the generation of static electricity in the co2 cloud. Air operated alarms may be used provided the air supply is clean and dry.
2. Electrically operated alarms: When electrically operated alarms are used, the arrangements are to be such that the electric actuating mechanism is located outside the pump-room except where the alarms are certified to be intrinsically safe.