Suppression gas actuation can be achieved by manual, hydraulic or electrical means.
Any method of actuation is acceptable within the standards, however we come across installations where little care is taken over this leading to systems that may never actuate at all defeating the whole purpose of why the gas system was installed in the first place.
A common problem encountered is multiple actuators on the same circuit, little thought given to the current draw of these actuators, some are known to draw more than one amp on firing and the gas control unit fuse being rated at one amp.
The distributor information pamphlet should be studied to determine what the current draw of the actuator in use is and then calculate if several of these actuators can be operated at the same time.
One must know:
- The current draw of the actuator.
- The capacity of the power supply installed.
- The value of the fuse in the gas control unit.
- The value of the fuse in the fire control panel.
- The stand by time of the batteries.
- The capability of any interface unit that is installed. It was recently discovered that an interface module commonly used in the market, designed for connection to detonator type actuators was being used for solenoid actuation.
- The operation of a detonator is a pulse of current and solenoids require constant power application. These banks of cylinders would not have been discharged.
Some contractors use separate power supplies for the gas actuator which is acceptable if:
- The current draw of the actuator can be supplied by the PSU installed.
- The current draw of the actuator does not blow the fuse in this unit.
- The unit has a charger and batteries installed.
- The batteries can operate for 24 hours under power fail conditions (keeping in mind the current required for the actuator).
- The power supply is monitored by the main gas control panel and reports power fail faults.
- Mains power must be derived from a dedicated labelled circuit breaker.
