Which foam application technique involves directing the foam stream onto an elevated object and allowing it to run down on the surface of a leaking fuel?

• A. Roll-on method
• B. Indirect method
• C. Rain-down method
• D. Bank-down method

Answer: (D)

This technique relies on using gravity to lay down a protective foam blanket over a hydrocarbon spill. By directing the foam stream at an elevated object, the foam cascades down onto the surface of the leaking fuel, spreading across it as it flows. This downward run creates a continuous foam layer that cools the fuel, separates it from the air, and helps prevent ignition or reignition by smothering the surface.

This approach is especially effective when you want rapid, blanket coverage of a spill from a higher point, leveraging gravity to distribute the foam evenly across the surface. Other methods either pour foam directly onto the surface from a lower point (not using an elevated target), or rely on foam landing as a rain-like shower or being applied around the fire rather than forming that downward, surface-wide blanket.