What foam application method should be used on open-top storage tank fires?

• A. Direct application
• B. Fog blanket
• C. Bounce-down
• D. Roll-on

Answer: (C)

When fighting open-top storage tank fires, the goal is to blanket the liquid surface with foam to cool and smother the fuel. The bounce-down method achieves this best by delivering foam from above with a steep angle so the foam strikes the surface and then cascades downward, spreading across the top and down the tank sides. This creates a thick, continuous foam blanket quickly over a large, flat surface, which is ideal for open-top tanks and helps prevent reignition by covering the fuel and cooling it.

Direct application focuses foam onto the flame or a small area, which may cause splashing and uneven surface coverage. A fog blanket can be blown away by wind and may not provide the stable blanket needed for open-top tanks. Roll-on delivers foam from the edge across the surface, but bounce-down is the most efficient for quickly forming a full-surface foam layer in open-top tank scenarios.