The Comparison of CAF with air aspirated and unexpanded foam water solutions

Air aspirated foam is created close to or in the nozzle by entraining air with a water jet and impacting on one or more obstacles. Some of the energy of the stream is used to agitate the mixture and foam is produced. 'Foam-water' refers to a foam solution of water and foam concentrate that has not been expanded by air. Compressed-air foam (CAF) has been proven to be an effective fire suppression material for both Class A and B fires, however, the effectiveness of CAF compared to air-aspirated systems and foam water systems has not yet been quantified. While air-aspirated foam systems have been around for many years the development of high quality Aqueous Film-Forming Foam (AFFF) concentrates have allowed foam systems with little or no air expansion to be used in controlling large flammable liquid fuel fires. To effectively compare these systems a series of 22 full scale fire tests were conducted with CAF, air-aspirated foam and foam water solution using 4.64 m2 pool fire. This paper describes a series of 22 full scale Class B fire tests designed to compare CAF, air-aspirated, and foam water solution in extinguishing a 4.64 m2 pool fire in accordance with the CAN/ULC-S560-98 Standard for Category 3 Aqueous Film-Forming Foam (AFFF) Liquid Concentrates [1]. In addition to visual observations, radiant heat flux was also measured at a point 1.83 m from the edge of the fuel pan and 1.5 m off the ground.
8th Fire Suppression and Detection Research Application Symposium: 21 January 2004, Orlando, Florida