Which type of fire extinguisher is suitable for Class B fires?

The AFFF (Aqueous Film-Forming Foam) extinguisher is specifically designed to combat Class B fires, which involve flammable liquids such as gasoline, oil, and fat. AFFF works by creating a film that suppresses the release of flammable vapors and smothers the fire, effectively cutting off the oxygen supply. This film also helps to cool the surface and prevents re-ignition.

In contrast, water extinguishers are ineffective against Class B fires because applying water can spread the burning liquid due to its lower density. Diatomaceous Earth extinguishers are not standard and typically do not serve as a primary method for extinguishing Class B fires. CO2 extinguishers can be effective for Class B fires, as they displace oxygen, but they do not provide cooling and can allow for re-ignition, which limits their utility compared to AFFF. Thus, the AFFF extinguisher is highly regarded for its effectiveness and dual-action capabilities in extinguishing Class B fires.