May need to move the hose line or use multiple lines to cover the material Use only on a pool of flammable product on open ground.ĭirect the foam stream onto the ground in front of the product involved. Methods differ from when applying Class A foam There are 2 main application techniques of applying foam onto a fire, recognized by the European (EN1568) and international (ISO7203) standards: AR-AFFF must be used in areas where gasoline is blended with oxygenates, since the alcohols prevent the formation of the film between the FFFP foam and the gasoline, breaking down the foam, and rendering the FFFP foam virtually useless. The most flexibility is achieved by AR-AFFF or AR-FFFP. High-performing FFF are viable alternatives to AFFF and AFFF-AR for various applications. AFFF is the best for spills of jet fuels, FFFP is better for cases where the burning fuel can form deeper pools, and AR-AFFF is suitable for burning alcohols. Low-expansion foams are used on burning spills. High-expansion foams are used when an enclosed space, such as a basement or hangar, must be quickly filled. Protein foams include regular protein foam (P), fluoroprotein foam (FP), film-forming fluoroprotein (FFFP), alcohol-resistant fluoroprotein foam (AR-FP), and alcohol-resistant film-forming fluoroprotein (AR-FFFP).Įvery type of foam has its application. They flow and spread slower, but provide a foam blanket that is more heat-resistant and more durable. Unlike synthetic foams, protein foams are bio-degradable. Protein foams contain natural proteins as the foaming agents. Fluorine-free foams (FFF, also called F3) are mostly based on hydrocarbon surfactants and is free of any fluorosurfactant.Alcohol-resistant aqueous film-forming foams (AR-AFFF) are foams resistant to the action of alcohols and can form a protective film.Aqueous film forming foams (AFFF) are water-based and frequently contain hydrocarbon-based surfactants such as sodium alkyl sulfate, and fluorosurfactants, such as fluorotelomers, perfluorooctanoic acid (PFOA), or perfluorooctanesulfonic acid (PFOS).They have limited post-fire security and are toxic groundwater contaminants. They provide better flow and spreading over the surface of hydrocarbon-based liquids, for faster knockdown of flames. Synthetic foams are based on synthetic surfactants. The use of class A foam on a class B fire may yield unexpected results, as class A foams are not designed to contain the explosive vapours produced by flammable liquids. Class B foams Ĭlass B foams are designed for class B fires-flammable liquids. Favourable experiences led to its acceptance for fighting other types of class A fires, including structure fires. This aids fire suppression and can prevent reignition. It penetrates and extinguishes embers at depth. Class A foams lower the surface tension of the water, which assists in the wetting and saturation of Class A fuels with water. methyl tert-butyl ether (MTBE), or fires of liquids based on or containing polar solvents.Ī fire truck demonstrating Class A foam in a CAFS systemĬlass A foams were developed in the mid-1980s for fighting wildfires. Alcohol-resistant foams are used in fighting fires of fuels containing oxygenates, e.g. Alcohol-resistant foams contain a polymer that forms a protective layer between the burning surface and the foam, preventing foam breakdown by alcohols in the burning fuel. High-expansion foams have an expansion ratio over 200–1000 and are suitable for enclosed spaces such as hangars, where quick filling is needed.Medium-expansion foams have an expansion ratio of 20–100.Low-expansion foams, such as aqueous film forming foams (AFFFs), have an expansion ratio of less than 20, are low-viscosity, mobile, and can quickly cover large areas.Other components of fire-retardant foams are organic solvents (e.g., trimethyl- trimethylene glycol and hexylene glycol), foam stabilizers (e.g., lauryl alcohol), and corrosion inhibitors. The surfactants used must produce foam in concentrations of less than 1%. Firefighting foam was invented by the Russian engineer and chemist Aleksandr Loran in 1902. Its role is to cool the fire and to coat the fuel, preventing its contact with oxygen, thus achieving suppression of the combustion. Firefighters sprayed foam on structures in the Mammoth Hot Springs complex on 10 September 1988 during the Yellowstone Firesįirefighting foam is a foam used for fire suppression.
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