What is the primary method used to extinguish Class B fires?

The primary method used to extinguish Class B fires, which involve flammable liquids such as gasoline, oil, and paints, is smothering. This method works by cutting off the fire's supply of oxygen, which is essential for combustion. By effectively covering the burning material with a non-flammable substance, such as foam or a blanket, the oxygen is deprived, causing the flames to be extinguished.

It's important to note that cooling with water is not suitable for Class B fires, as water can spread the burning liquid or cause violent reactions with certain flammable substances. Flushing with foam is employed as a secondary method, as foam can simultaneously smother and cool the fire, but it's not the primary approach. Displacement of oxygen is a more general strategy used for various fire classes and is not typically a standalone method for extinguishing Class B fires. Therefore, smothering remains the most effective and widely practiced method for addressing such fires.