I noticed something very strange with a new fire suppression system. There were no valve controls on the system, of the four bottles, only one was controlled. I had to look further into this.
One of the sites I work on had installed an Intergen Fire Suppression system. The basic idea is that in the event of a fire, enough oxygen is displaced from the room, that a fire cannot be sustained, but humans will remain conscious.
When I looked at the system I was mighty confused. Four high pressure cylinders indicate a high pressure non-liquefied gas. Makes sense when you look at the mix – Nitrogen, Argon, CO2 – not likely to liquefy under pressure at room temperature. A large diameter medium pressure line led to the room with no valves on it. This line was open at the room end with a simple nozzle, no valves along the way.
There was a valve on each cylinder, but no controls to any but the first one.
The first cylinder below has a both an electrical and manual release attached – but what about the other three bottles?
The control valve on each slave cylinder is the interesting bit. When pressure is sensed in the line, it opens the bottle, and remains open until the bottle is empty. Basically it’s a pneumatically operated slave. The pressure in the line is created by the first bottle’s discharge, triggered electrically, and the restriction of the line and nozzles.
And yes, they installed vents in the room to let out the extra air. When you add another 50% of gas to a room, the displaced gas has to go somewhere, or develop an unlikely amount of pressure. They would not be the first to forget the vent.