What is the most common type of fire extinguisher used for ordinary combustibles?

The Class A fire extinguisher is specifically designed to combat fires involving ordinary combustibles such as wood, paper, and textiles. These materials burn in a manner that generates embers and ash, making it essential to use an extinguisher that effectively cools the burning material. Class A extinguishers typically contain water or foam agents, which are capable of directly addressing the heat of the fire to extinguish it efficiently.

The other classes of extinguishers address different types of fires. Class B extinguishers are for flammable liquids and gases, while Class C extinguishers are meant for electrical fires. Class D extinguishers are specifically for combustible metals. Thus, the Class A fire extinguisher is the most appropriate choice for dealing with ordinary combustible materials.