Question 789 Deck Safety

The correct answer is C) completely covers the top of the burning liquid. Firefighting foam is effective when it forms a continuous blanket or layer over the surface of the burning liquid. This blanket or layer cuts off the fuel's supply of oxygen, smothering the fire. The foam must completely cover the top of the burning liquid to effectively smother the flames and prevent re-ignition. The other options are incorrect because: A) Penetrating to the bottom is not necessary for the foam to be effective. B) Keeping the foam saturated with water is not the primary mechanism for its effectiveness. D) Mixing with the burning fuel oil would actually decrease the foam's ability to smother the fire.