Gas extinguish systems have gas stored in self contained bottles, and when activated the gas reduces the oxygen levels to below the percentage needed for combustion or create a chemical reaction to break the “fire triangle” (heat, fuel, oxygen).
Gas extinguish systems are not as common as fire sprinkler systems. They are used in areas where water damage must be avoided, for example in rooms where lots of electric panels, servers and computers, laboratories and archives are present.
The system is also called Clean Agent Fire suppression. Such a system typically consists of the agent (gas), agent storage containers, agent release valves, fire detectors, fire detection system (wiring control panel, actuation signalling), agent delivery piping, and agent dispersion nozzles.
The gasses used are mainly environmental safe, and have 3 ways to suffocate the Fire:
· Reduction of heat. Here the HFC-family gasses (Heptaflouropropane) are typically used.
· Reduction of oxygen. Here argon, argonite and carbon dioxide are typically used.
· Inhibitors of heat and oxygen. Typically used are Halon, Pentaflourethane (global warming potential)
There are two ways of applying the gas – either flooding the concealed space totally or local application direct onto a fire.
There is a high risk to people of suffocation when using gas in enclosed spaces, so life safety systems need to be installed to warn people, enabling them to escape the room.