What must you do when using the bank down method for foam application?

The bank down method for foam application is focused on effectively suppressing flammable liquid fires, particularly in situations where there are pools of burning fuel. Ensuring that the tank wall is intact is crucial because any breach could lead to a rapid drainage of the flammable liquid, making firefighting efforts more challenging. An intact tank wall helps maintain the containment of the fuel, allowing the foam to effectively blanket the fuel surface and suppress the fire.

When the tank is compromised, the foam may not provide effective coverage or stay in place long enough to suppress the flames, reducing the overall effectiveness of the firefighting efforts. Therefore, confirming the structural integrity of the tank is a necessary first step when employing this method.

While options such as applying foam only after ignition or directing foam toward the sides of the pool may refer to specific techniques, they do not address the critical factor of containment that affects the success of the foam application. Additionally, using water ahead of foam application could introduce complications rather than provide support under certain fire conditions.