Roll on method involves which action?

• A. Directing the foam stream on the ground near the front edge of a burning liquid spill, allowing the foam to roll across the surface.
• B. Directing the foam stream onto a vertical surface and allowing it to run down, then spreading across the pooled fuel.
• C. Directing foam stream into the air above the fire to gently fall on the fuel.
• D. Directing foam at a 45-degree angle to create a fan pattern.

Answer: (A)

The roll-on method is a foam application technique used on burning liquid spills. You direct the foam stream on the ground near the front edge of the spill so the foam rolls across the surface, forming a continuous blanket. This rolling foam blanket cools the fuel and separates it from the air, helping to smother the fire and prevent reignition. It’s especially effective for hydrocarbon spills on the ground because it covers the surface evenly and stays in contact with the fuel. Directing foam onto a vertical surface, streaming foam into the air, or trying to create a fan pattern won’t establish the same blanket across the liquid surface, so they’re not suitable for achieving the same extinguishing effect.