text: * 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.
  * Medium-expansion foams have an expansion ratio of 20–200.
  * High-expansion foams have an expansion ratio over 200–1000 and 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 are used in fighting fires of fuels containing oxygenates, e.g. methyl tert-butyl ether (MTBE), or fires of liquids based on or containing polar solvents.