How should foam be applied according to the Sweep or Roll-on method?

Using the Sweep or Roll-on method, foam should be applied onto a pool of liquid on open ground because this approach allows the foam to effectively blanket the surface of the flammable liquid, creating a barrier that suppresses vapors and prevents ignition. The method emphasizes spreading the foam evenly over the surface, ensuring that it flows across the burning liquid and effectively smothers the flames.

When foam is applied correctly in this manner, it not only extinguishes the fire by displacing oxygen and cooling the surface but also prevents re-ignition by sealing off the liquid surface. This technique is particularly effective for combating fires involving flammable liquids where a pool fire is present, making it a critical practice in firefighting foam application.

In contrast, applying foam directly onto the flames, using high-pressure nozzles, or handheld extinguishers is less effective as these methods do not promote proper foam spread or may even disturb the burning liquid, worsening the situation.