How Foam Extinguishes Fire
In chemical terms the combustion process is a fast running reaction between a flammable material and atmospheric oxygen induced by the ignition temperature. To extinguish a fire the burning material must be separated from the atmospheric oxygen or cooled down to below the combustion temperature. This is exactly what fire extinguishing foam does. The following fire extinguishing effects are utilised when using fire extinguishing foam:
The preventive application of foam onto spilled volatile products prevents emissions harmful to the environment. This also significantly reduces the danger of fire.
Flooding spaces, channels, plant parts, etc. with high or medium expansion foam represses the the atmospheric oxygen and flammable gases necessary for the combustion process.
The low thermal conductivity of the foam insulates flammable material which has not yet caught fire or has
already been extinguished against thermal radiation and ignition sources.