



Class B foam concentrates are designed to extinguish class B flammable liquids. There are two types of class B flammable liquids. The first type is a non-polar flammable liquid which is immiscible in water. Non-polar flammable liquids include gasoline, heptane and crude oil. The second type of flammable liquid is a polar flammable liquid which is miscible in water. Polar solvent liquids include isopropanol, methyl ethyl ketone (MEK) and methyl tertiary butyl ether (MTBE). Generally all foams are designed to be used on non-polar solvents but only polar solvent or alcohol resistant concentrates are effective on polar solvents.
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Standard AFFF (Aqueous Film-Forming Foam) is typically available in 1%, 3% and 6% nominal concentrations. AFFF concentrate is a synthetic foam made with fluorinated surfactants and can produce an air-excluding foam blanket. In addition, AFFF foam solutions provide a vapor sealing film on non-polar flammable liquids. 3/6% AR-AFFF for use at 3% on non-polar solvents and 6% on polar solvents Fluoroprotein foam is typically available in 3% and 6% nominal concentrations. Fluoroprotein foams use protein and fluorochemical surfactants. |
High expansion foam concentrate is a mixture of surface-active agents and synthetic foaming agents. This foam solution must be applied with high expansion foam generating equipment, which produces a foam with an expansion ratio of approximately 500 to 1. High expansion foam extinguishes a fire by cooling the fire and excluding oxygen from the fire. High expansion foam can be used on class A, non-polar class B and polar Class B fires.
Class A foam concentrates are typically used at concentrations from 0.1% to 1% in water. By adding class A foam concentrate to water, the resulting foam spreads over the class A fuel and slowly releases water to cool the fire. The foam concentrate also reduces the surface tension of the water enabling it to better penetrate the fuel.

