What is indicated by the "B" rating on a fire extinguisher?

The "B" rating on a fire extinguisher indicates that the extinguisher is effective on Class B fires, which involve flammable liquids such as gasoline, oil, and other similar substances. This rating signifies that the extinguisher has been tested and proven capable of suppressing fires fueled by these types of materials.

Class B fires are distinct from those involving solid combustibles (Class A), electrical equipment (Class C), or metals (Class D), which require different fire suppression methods and extinguishing agents. The classification system helps in selecting the appropriate extinguisher for the specific type of fire one might encounter, ensuring effective response and safety. Understanding the ratings on fire extinguishers is crucial for both compliance and safety measures in various environments where fire hazards may be present.