Which of the following is the best extinguisher choice for a Class B fire in a Main Space?

• A. PKP
• B. ABC
• C. CO2
• D. Water

Answer: (A)

For a Class B fire involving flammable liquids, you want an extinguisher that quickly knocks down the flame and prevents vapor from feeding the fire. PKP, a dry chemical powder, does this effectively by interrupting the flame’s chemical reactions and coating the liquid surface to form a crust that helps prevent reignition. It responders fast in a Main Space, where quick action is essential, and its reach and impact make it well-suited for hydrocarbon fires.

ABC powder can extinguish but isn’t as fast or targeted for hydrocarbon fuels, and it leaves residue that can hamper equipment and ventilation. CO2 is good for small, contained or electrical fires but is less reliable for larger liquid fires and can displace oxygen in enclosed spaces. Water is inappropriate for Class B fires because it spreads the flammable liquid and spreads the fire.

So PKP is the best choice because it delivers rapid, effective knockdown of flammable-liquid fires in the Main Space.