A recent false gas dump was brought to the attention of the FSIB and interesting facts emerged.
One afternoon in November an employee of an insurance company needed to enter a server room protected with an automatic gas extinguishing system. On approaching the area operation protocols required her to isolate the gas system by switching the gas system control from “automatic” to “manual”.
When she touched the key switch a spark jumped from her finger to the metal key switch and an immediate Shhhhhh noise was heard.
The FM 200 modular gas extinguishing cylinder had actuated and dumped the gas into the room. A senior engineer of the insurance company was summoned who in turn contacted the original installation contractor. The contractor promptly arrived to inspect the system. He downloaded the log from the addressable fire panel to discover that nothing untoward was recorded. The detectors, nor the warning alarms, operated but the gas had discharged.
The contractor called a subsequent meeting with the owner and the product manufacturer to investigate the problem further. The technicians conducted several tests and took many measurements.
All components of the system were undamaged and found fully functional, readings indicated correct voltages and no damage of any nature was found.
It must be noted that the separate addressable gas control unit was mounted on a partition wall and the area around the gas control unit was carpeted. It was then determined that static electricity had been the cause of the gas discharge. Static electricity had gone through the key switch looking for a path to earth and must have triggered some component within the Gas Control Unit to send the voltage required to discharge the gas...
The GCU mounted on the partition wall was found not to be earthed. The housing was not earthed and with static created by walking on the carpet it had to find a path out.
The question has to be raised as to how many other false gas discharges have happened due to static through un- earthed housings? Many GCU’s are connected to steel conduit which being earthed eliminate this problem. Others are not.
The FSIB issue a word of advice to all service technicians –