Question 335Safety & Environmental - Assistant Engineer

The correct answer is C) smothering the fire. For a Class B fire, which involves flammable liquids and gases, the fire is extinguished by using foam to smother the fire and cut off the oxygen supply. Foam blankets the surface of the flammable liquid, preventing the release of flammable vapors that feed the fire. This smothering action is the primary mechanism by which foam extinguishes Class B fires, rather than cooling the surface or replacing the fuel source. The other answer choices are incorrect because they do not accurately describe the primary extinguishing mechanism for a Class B fire using foam. Replacing the fuel (A) and cooling the surface (B) are not the main ways foam extinguishes these types of fires.