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Firefighting foam is a foam used for fire suppression. Its role is to cool the fire and to coat the fuel, preventing its contact with oxygen, resulting in suppression of the combustion. Fire-fighting foam was invented by the Russian engineer and chemist Aleksandr Loran in 1902.〔(Loran and the fire extinguisher ) at p-lab.org 〕 The surfactants used must produce foam in concentration of less than 1%. 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. Low-expansion foams have an expansion rate less than 20 times. Low-expansion foams such as AFFF are low-viscosity, mobile, and able to quickly cover large areas. Medium-expansion foams have an expansion ratio of 20–100. High-expansion foams have an expansion ratio over 200–1000. They are suitable for enclosed spaces such as hangars, where quick filling is needed. 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. Alcohol-resistant foams should be used in fighting fires of fuels containing oxygenates, e.g. MTBE, or fires of liquids based on or containing polar solvents. ==Class A foams== Class A foams were developed in mid-1980s for fighting wildfires. Class A foams lower the surface tension of the water, which assists in the wetting and saturation of Class A fuels with water. This aids fire suppression and can prevent reignition.〔 〕 Favorable experiences led to its acceptance for fighting other types of class A fires, including structure fires. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Firefighting foam」の詳細全文を読む スポンサード リンク
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