What is necessary when applying fire fighting foam?

• A. Intermittent application
• B. Continued, uninterrupted application until extinguishment
• C. Short bursts
• D. Pause for cooling

Answer: (B)

Foam works by forming a continuous blanket on the fuel surface, which cools the liquid, separates the fuel from the air, and suppresses vapors that can cause reignition. Because flammable liquids keep releasing vapors while heat is present, maintaining that foam barrier until the fire is completely extinguished is essential. Any interruption—whether in bursts, pauses for cooling, or stopping and starting again—can let the foam layer break or retreat, re-expose the fuel, and risk reignition. Therefore, apply foam continuously and evenly until the fire is out and the surface has cooled enough to prevent reflash.