What is the key characteristic of Class B fires?

Class B fires are primarily characterized by their involvement of flammable liquids. These can include substances such as gasoline, oil, paint, and solvents. This classification is crucial for understanding how to effectively fight such fires, as they require specific extinguishing agents that can effectively smother or cool the burning liquid.

Using water on a Class B fire can be dangerous, as it may cause the flaming liquid to spread. Instead, firefighters use foam, dry chemical extinguishers, or CO2 extinguishers, which are designed to displace oxygen and reduce vapor production from the burning liquid. This understanding is not only vital for the safety of firefighters but also for effectively protecting property and controlling the fire.

Other classifications, such as those involving electrical equipment, ordinary combustibles, or combustible metals, pertain to different types of fires that require distinct approaches for extinguishment and have their unique hazards.