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Unlike water, these fire fighting agents are non-conductive and non-corrosive, making them safe to use on and around live electrical equipment. There is no residue to cleanup, no lingering materials to slowly degrade equipment, and no need for an expensive "Disaster Recovery" process. Operations are brought back online and productive in a very short time. .
Most agents are also safe to use in occupied areas. These agents have undergone extensive toxicity testing to prove they are compatible with people. While NFPA recommends always exiting the hazard in the event of a fire, it is important that people not be harmed by the extinguishing system. .
One emerging technology in the fire suppression industry is the use of water mist systems. Interest in water mist technology has heightened over the past two years. There are several manufacturers with developed products on the market, and more entering the market. Two major conferences were held in 1993 on the topic, and the National Fire Protection Association (NFPA) has formed a committee to write an installation standard for water mist systems. The NFPA 750 Committee "Standard for the Installation of Water Mist Fire Suppression Systems," has formed a task group to summarize the data on water mist fire suppression. An international literature search was conducted, and based on the results of the search and input from the main committee, eight topic areas were identified.
The water mist system works by using three basic types of nozzles to create a fine water spray: high pressure single orafice nozzles, low pressure single fluid nozzles, and air atomization nozzles. The high pressure nozzles usually operate at pressures of 10MPa and up, producing droplets whose mean diameters are in the range of 30 to 100 pm. Low pressure single fluid nozzles usually operate at pressures of .6 Mpa to 1 Mpa. These low pressure nozzles produce a larger drop diameter than their high pressure counterparts.