Certain kinds of facilities and operations present unique fire protection challenges. Facilities like telecommunication and data centers, process control rooms, high-value medical facilities, and museums and libraries, to name a few, require not only rapid extinguishment of a fire, but also the use of suppression agents that are nonconductive, do not pose cleanup difficulties, and are not hazardous to personnel. Since the phaseout of halogenated agents was initiated in 1994 due to the detrimental effect of halons on the environment, clean agent fire suppression systems have been used to meet the fire protection needs for many of the above types of applications.
Clean agents are nonconducting fire extinguishants that vaporize readily and do not leave a residue upon evaporation. Clean agents consist of halocarbons or inert gases, and are subject to specific evaluation with regard to their hazards to personnel and their effect on the environment prior to being officially classified as a clean agent. Halocarbons serve to extinguish fire primarily by cooling, whereas inert gases serve to extinguish fire by diluting the concentration of oxygen in the vicinity of the combustion reaction zone. Clean agents are normally stored under high pressure as a liquid and readily vaporize when released to the atmosphere upon discharge from a properly designed system.