Firefighter II Certification Practice Exam 2025 – Ontario OFM Complete Prep Guide

Class B fire extinguishers are specifically designed to combat fires that involve flammable liquids, such as gasoline, oil, and paints. These extinguishers contain agents that can effectively suppress flames generated by these types of materials, often using foam, carbon dioxide (CO2), or dry chemical agents that form a barrier between the fuel and the oxygen needed to sustain the fire.

Water fire extinguishers are not suitable for Class B fires because water can spread the flammable liquid, exacerbating the fire. Similarly, Class A fire extinguishers are intended for ordinary combustibles like wood and paper and are ineffective against flammable liquid fires. Class C extinguishers are designed for live electrical fires and use non-conductive agents, making them inappropriate for flammable liquids as well.

Therefore, a Class B fire extinguisher is the most suitable choice for addressing fires caused by flammable liquids, as it employs methods and materials that specifically address the unique hazards presented by this type of fire.