In which method of foam application is a bank of foam formed on the ground in front of the flammable liquid pool and pushed over the pool?

The Roll-in method of foam application involves creating a bank of foam on the ground in front of a flammable liquid pool and then pushing that foam over the surface of the liquid. This technique is particularly effective for establishing a protective barrier that smothers the flames and prevents the ignition of vapors. By rolling the foam into the fire, it maximizes coverage and minimizes the risk of re-ignition.

In contrast, the other methods have different applications and effectiveness scenarios. The Rain-down method involves applying foam from above, typically from a wide-angle nozzle, which might not create a sufficient barrier over a volatile surface. The Bounce-off method requires the foam to strike a surface and then spread out, which can be less efficient for pooling liquids. The Foam blanket method creates a persistent layer of foam from the outset, but it does not involve the active pushing or rolling of foam over the liquid, which is a defining feature of the Roll-in technique. Each method has unique advantages, but the Roll-in method is specifically designed for the situation described in the question.