The numerical rating for Class B portable fire extinguishers is based on what?

The numerical rating for Class B portable fire extinguishers specifically reflects the amount of flammable liquid fire that the extinguisher can effectively extinguish. This rating indicates the square footage that an operator can approximately cover for extinguishing a fire involving flammable liquids, such as gasoline or oil. For example, a Class B extinguisher rated at 10 means that it is capable of putting out a fire that covers an area of 10 square feet.

Understanding this rating is crucial for firefighters and operators because it informs them about the effectiveness and suitability of an extinguisher for various fire situations. This emphasizes the importance of having the right type and rating of extinguisher available for specific fire hazards, enhancing safety and effectiveness in emergency response.