Which of the following best describes the function of foam in fire suppression?

The function of foam in fire suppression primarily revolves around its ability to smother flames by forming a blanket over the burning material or liquid. When foam is applied to a fire, especially those involving flammable liquids, it creates a barrier that prevents the release of flammable vapors into the atmosphere. This suffocation effect significantly reduces the oxygen available for combustion, thereby extinguishing the fire effectively.

Foam serves not only to extinguish flames but also to prevent re-ignition of flammable surfaces, making it particularly valuable in firefighting operations involving liquids where other methods may not be as effective. The physical properties of foam allow it to adhere to surfaces and maintain coverage, creating an insulating layer that both cools and smothers. Thus, this capability to float on and cover burning liquids while inhibiting flammable vapor release is a key aspect of its role in firefighting.