Which foam application method is well suited for a flammable liquid spill near the exterior wall of a building?

• A. Bank-Down Method
• B. Direct Application
• C. Fog Blanket From A Distance
• D. Ring-Fog Method

Answer: (A)

When dealing with a flammable liquid spill near a vertical surface, the goal is to create a stable, continuous barrier of foam that blankets the liquid and protects the wall from ignition and vapors. The bank-down method builds a foam bank along the spill that climbs up the wall and forms a solid protective layer. This directional application confines the liquid, cools it, and reduces vapor release, which is crucial when a building’s exterior wall is in close proximity. The foam bank acts as a barrier to prevent the liquid from spreading toward the wall or running down toward foundations, while firefighters stay protected behind the foam as it anchors to the surface.

Direct application can cover the spill but may not establish a persistent barrier against the wall or wind. A fog blanket from a distance covers more area but risks drifting away and not maintaining a robust protective layer against the vertical surface. The ring-fog method concentrates on creating a vapor-suppressing ring around the spill but may leave the wall area exposed and is less effective at forming a continuous barrier along the exterior structure.