In Fire Extinguishers, Fire Safety, Fire Suppression, News

Fighting fires with the appropriate foam allows firefighters to do their job more effectively, efficiently and safely.  The foam acts as a fire suppressant by cooling and coating the fire to prevent contact with oxygen.  There are many types of firefighting foams for different types of fires.

Class A Foams

Class A firefighting foams combine water and foaming detergent surfactants for fighting wildfires and structure fires.  When a surface is treated with the foam, it is more difficult for fuels to ignite because their level of hydration has been raised.

Class B Foams

Class B firefighting foams are designed for flammable liquid fires.  They can contain the explosive vapors produced by flammable liquids.  There are two major subtypes.

Synthetic foams – based on synthetic surfactants. They are toxic groundwater contaminants that provide better flow and spreading over the surface of hydrocarbon-based liquids resulting in a faster knockdown of flames.

  • Aqueous film forming foams (AFFF) – are water based and are used mainly for jet fuel spills.
  • Alcohol-resistant aqueous film-forming foams (AR-AFFF) – are resistant to the action of alcohols and can form a protective film. It is suitable for burning alcohols and must be used in areas where gasolines are blended with oxygenates, since the alcohols prevent the formation of the film between the FFFP foam and the gasoline, breaking down the foam and rendering the FFFP foam virtually useless.

Protein foams – contain natural proteins as the foaming agents.  They are biodegradable with a slower spread and flow.  The foam blanket formed is more heat-resistant and more durable.

  • Regular protein foam (RP) – produces a homogeneous, stable foam blanket that has excellent heat resistance, and drainage characteristics.
  • Fluoroprotein foam (FP) – provides fast fire knockdown, better resistance to fuel pick-up and greater compatibility when used in conjunction with dry-chemical extinguishing agents. It should not be used on fires involving ethanol-gasoline blends containing more than 10 percent ethanol.
  • Film-forming fluoroprotein foam (FFFP) – releases an aqueous film on the surface of the hydrocarbon fuel that prevents volatile vapors from escaping the liquid.
  • Alcohol-resistant fluoroprotein foam (AR-FP) – used in fires involving all types of hydrocarbon or solvent fuels.
  • Alcohol-resistant film-forming fluoroprotein foam (AR-FFFP) – creates a tough membrane, which separates the foam from the fuel and prevents the destruction of the foam blanket.

Call Fire Control Systems to determine which type of foam extinguisher is best for you.

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