What is the best extinguishing agent for a chimney fire?

• A. Water Fog
• B. Dry Chemical
• C. Foam
• D. CO₂

Answer: (B)

Chimney fires burn creosote deposits in the flue, so the goal is to knock down the flame quickly and prevent reignition by stopping the chemical reactions happening in the flame. Dry chemical powder does this best because it blankets the hot creosote and interrupts the flame reactions, providing fast knockdown and a lasting effect. Water can cool, but it often can’t reach all deposits inside a narrow flue and can create steam, structural damage, or push burning embers into the building. Foam isn’t well suited to creosote fires, since these aren’t a surface liquid fuel that foam can spread effectively, and CO2 displaces oxygen without delivering the rapid, heat-absorbing knockdown that dry chemical offers. So dry chemical powder is the most effective option for extinguishing a chimney fire.