What is sodium bicarbonate primarily used for in fire extinguishers?

Sodium bicarbonate is primarily used in Class B fire extinguishers, which are designed for flammable liquids such as gasoline, paint, or solvents. When sodium bicarbonate is used in a fire extinguisher, it works as a dry chemical agent that helps suppress fires by releasing carbon dioxide when it decomposes upon heating. This action helps to smother the flames and interrupt the chemical reactions that sustain combustion in flammable liquid fires.

Class B fire extinguishers are specifically tailored for situations involving flammable liquids, making them the suitable choice for sodium bicarbonate's properties. Other classes of extinguishers, such as Class A, Class C, and Class K, address different types of fires, such as ordinary combustibles, electrical fires, and cooking oils or fats, respectively. Therefore, the application of sodium bicarbonate is most appropriate for Class B situations, highlighting its efficacy in managing fires caused by flammable liquids.