Which statement about the application of dry chemical on a Class B fire is false?

• A. The use of dry chemical agents reduces the chance of flashback
• B. Dry chemical can be effective on Class B fires
• C. Dry chemical creates a film on the surface
• D. Dry chemical should be applied from a safe distance

Answer: (A)

Dry chemical extinguishing agents work on Class B fires mainly by interrupting the flame’s chemical reactions and by coating the liquid surface. The powder helps stop the flame chemistry and blankets the fuel, creating a barrier that slows vapor release and helps prevent reignition. This makes them effective for hydrocarbon fires, and you should apply them from a safe distance to thoroughly cover the liquid.

The statement about reducing the chance of flashback isn’t reliable. Flashback involves vapors traveling back to the ignition source, and while dry chemical can suppress the flame and blanket the fuel, it doesn’t guarantee prevention of flashback. Controlling the fuel source and using proper extinguishing technique are the primary protections against flashback.