Question 792 Deck Safety

The correct answer is D) Foam sets up a vapor barrier over a flammable liquid preventing flammable gases from rising. This is the correct answer because foam works by forming a blanket over the surface of a flammable liquid, which prevents the release of flammable vapors that can fuel the fire. The foam creates a vapor barrier that cuts off the fire's supply of oxygen and smothers the flames. The other options are incorrect because: A) Foam is not effective for controlling gases from compressed gas cylinders, which require different firefighting methods. B) The air bubbles in foam do not act as an insulator for class C (electrical) fires. C) The effectiveness of foam actually decreases as the liquid temperature increases, as the foam becomes less stable.