In a Class B extinguisher, what does the number indicate?

The number in a Class B extinguisher signifies the coverage area in square feet that the extinguisher can effectively protect. Class B extinguishers are designed to combat fires involving flammable liquids and gases such as gasoline, oil, and paint. The numeral rating indicates the approximate number of square feet that the extinguisher can cover, allowing users to assess whether it is suitable for the size and type of risk they face.

For example, if a Class B extinguisher has a rating of 10, it can effectively cover a fire involving flammable liquids in an area of about 10 square feet. This system helps individuals choose the right extinguisher based on the specific fire hazards present in their environment, ensuring they have adequate protection against flammable liquid fires.