This classification of fire involves ordinary combustible material.

This classification of fire involves ordinary combustible material.

• A. Class A
• B. Class B
• C. Class C
• D. Class D

Answer: (A)

Fires involving ordinary combustibles are grouped together because these materials—like wood, paper, cloth, and trash—burn by oxidizing and typically leave behind ash. They’re characterized by their ability to be cooled; water effectively removes heat, stopping the flames from continuing. That heat-absorption property is why water-based extinguishing agents are especially suited for this class. In contrast, other classes cover different fuels: flammable liquids burn in Class B and are tackled by smothering or eliminating vapors; energized electrical equipment is Class C and requires non-conductive extinguishing methods or de-energizing the source; reactive metals are Class D and need specialized powders that interrupt the chemical reactions. So, the classification that includes ordinary combustible materials like wood, paper, and cloth is the one tied to those common everyday fuels.

Fires involving ordinary combustibles are grouped together because these materials—like wood, paper, cloth, and trash—burn by oxidizing and typically leave behind ash. They’re characterized by their ability to be cooled; water effectively removes heat, stopping the flames from continuing. That heat-absorption property is why water-based extinguishing agents are especially suited for this class. In contrast, other classes cover different fuels: flammable liquids burn in Class B and are tackled by smothering or eliminating vapors; energized electrical equipment is Class C and requires non-conductive extinguishing methods or de-energizing the source; reactive metals are Class D and need specialized powders that interrupt the chemical reactions. So, the classification that includes ordinary combustible materials like wood, paper, and cloth is the one tied to those common everyday fuels.