Water/Juice can only be used on which class of fires?

• A. Class B
• B. Class A
• C. All classes
• D. Class C

Answer: (B)

Water is effective for fires that involve ordinary combustibles—materials like wood, paper, cloth, and textiles. The key reason is cooling: water absorbs a large amount of heat as it heats up and turns to steam, lowering the fuel’s temperature below its ignition point and stopping the combustion process. That cooling effect is what makes water the best choice for these kinds of fires.

Water is not suitable for fires involving flammable liquids because it can spread the liquid across surfaces and worsen the fire. It also isn’t used for electrical fires, since water conducts electricity and can create shock hazards or spread flames along conductive paths. In aviation practice, you reserve water-based extinguishing for the ordinary combustible fires and use other agents for liquid fires or electrical fires.