What is the foam application method used for an ignited pool of liquid fuel on open ground?

The roll-on method is the appropriate foam application technique for an ignited pool of liquid fuel on open ground. This method involves rolling the foam over the fire, allowing it to flow across the surface of the burning liquid fuel. The foam forms a blanket that effectively smothers the flames and prevents re-ignition by separating the fuel from the air.

This approach is particularly useful in situations where a quick and effective suppression of a liquid fuel fire is needed, as it not only covers the flames but also spreads over the surface of the fuel, creating a barrier to further combustion. The roll-on method is best suited for scenarios involving large pools of flammable liquids, where direct application could disturb the fuel and exacerbate the situation.

The other foam application methods—such as the wet application method, poured method, and spray application method—are not as effective in this context. While they can be useful for different types of fires or in specific situations, for a large pool fire, the roll-on method provides a more effective way to control the fire rapidly and minimize the risk of flashback or flare-ups.