Foam extinguishes fires primarily through which method?

Foam extinguishes fires primarily through the method of smothering. This occurs because foam blankets the fuel surface, creating a barrier that prevents oxygen from reaching the fuel. By limiting the available oxygen, which is a critical component of the fire triangle, the foam effectively starves the fire, extinguishing it.

Additionally, the physical properties of foam contribute to its smothering capabilities. Foam consists of air-filled bubbles that, when applied to a fire, create a layer that isolates the fuel from the surrounding environment. This layer not only limits oxygen supply but also inhibits the release of flammable vapors from the liquid fuel, further enhancing the extinguishing process.

The other methods listed, such as cooling, displacement, and neutralization, do not accurately describe the primary function of foam in extinguishing fires. While some firefighting agents do operate through cooling (removing heat) or displacement (reducing oxygen concentration), foam specifically performs its most effective action by smothering the fire.