Water represents the ideal extinguishing agent for most fires. Fire sprinklers utilize water by direct application onto flames and heat. This action cools the combustion process and prevents ignition of adjacent combustibles.
Sprinkler systems are a series of water pipes which are supplied by a reliable water supply. At selected intervals along these pipes are independent, heat activated valves known as sprinkler heads. It is the sprinkler head which is responsible for water distribution onto the fire. Most sprinkler systems also include an alarm to alert occupants when a fire occurs.
During the incipient fire stage, heat output is relatively low and unable to cause sprinkler operation. As the fire intensity increases, however, the sprinkler’s sensing elements become exposed to elevated temperatures and they begin to deform. Assuming temperatures remain high, as they would during an increasing fire, the element will fatigue after an approximate 30 second to 4 minute period. This will release the sprinkler’s seals allowing water to discharge onto the fire. In most situations less than 2 sprinklers are needed to suppress the fire. In fast growing fire scenarios such as a flammable liquid spill, up to 12 sprinklers may be required for control.
Additional actions may occur when sprinkler activation happens. These include initiation of building and/or fire department alarms, operation of supplemental water supply systems, shutdown of selected electrical and mechanical equipment closing of fire doors and dampers, and suspension of processes.