AFFF or Firefighting foam is a foam used for fire suppression. AFFF 1% A is an aqueous film forming foam concentrate (AFFF) consisting of fluorocarbon and hydrocarbon surfactants blended with various solvents, preservatives and stabilisers. Its role is to cool the fire and to coat the fuel, preventing its contact with oxygen, resulting in suppression of the combustion. Low-expansion foams such as AFFF, have an expansion rate less than 20 times are low-viscosity, mobile, and can quickly cover large areas. The foam blanket blocks oxygen supply to the fuel. The liquid drains from the foam blanket and forms an aqueous film that suppresses fuel vapour and seals the fuel surface.
The low surface tension of the water-foam solution enables the aqueous film, although heavier than the burning liquid, to float on top of the liquid surface. Aqueous film forming foam (AFFF) is a highly efficient type of fire suppressant agent, used by itself to attack flammable liquid pool fires