Compressed Air Foam System

A compressed air foam system (CAFS) is used in firefighting to deliver fire retardant foam for the purpose of extinguishing a fire or protecting unburned areas.

Typical components include a water source, a centrifugal pump, foam concentrate tanks, a direct-injection foam proportioning system on the discharge side of the pump, a mixing chamber or device, a rotary air compressor, and control systems to ensure the correct mixes of concentrate, water, and air.

A compressed air foam system is defined as a standard water pumping system that has an entry point where compressed air can be added to a foam solution to generate foam. The air compressor also provides energy, which, gallon for gallon, propels compressed air foam farther than aspirated or standard water nozzles.

It is proven that CAFS attacks all three sides of the fire triangle simultaneously. The foam blankets the fuel, thereby reducing the fuel’s capacity to seek out a source of oxygen. The CAFS solution adheres to ceilings and walls, more readily aiding in rapid reduction in heat. Also, the opaque surfaces of the foam, as it adheres to walls and ceilings, shield the fuel source from radiant energy. (Brooks, 2005; Brooks, 2006)

CAFS may also refer to any pressurized water style extinguisher that is charged with foam and pressurized with compressed air.

The idea that water is not a perfect tool for fire extinguishment has been long noted, as by W. E. Clark (1991), "The process of extinguishing fire by water is cumbersome and generally costly … the cost of installing water mains large enough for required flow, the installation and maintenance of fire hydrants, and the acquisition and maintenance of fire department pumpers, fire hose, and nozzles, make water a fairly expensive extinguishing agent … the use of water is hardly the ideal way to extinguish fire … there must be a better method waiting to be discovered." (p. 75)

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