Bank down method involves which action?

• A. Foam is directed onto the vertical surface and allowed to run down, then spread across the pooled fuel.
• B. Foam is sprayed across the surface from a distance away.
• C. Foam is directed onto the ground away from the spill.
• D. Foam is applied directly on top of the fuel surface.

Answer: (A)

The bank down method relies on creating a foam blanket by directing foam onto a vertical or near-vertical edge of the spill and letting it flow downward into the pooled fuel. Gravity carries the foam across the surface, forming a continuous layer that cools the fuel and blankets the spill, helping to suppress vapors and prevent reignition. This approach uses the downward flow to quickly cover the surface, unlike methods that spray foam from a distance, place foam on the ground away from the spill, or apply foam directly on top of the fuel surface, which don’t establish that flowing, edge-to-surface blanket critical for large hydrocarbon spills.