How do multi-class dry chemical fire extinguishers work?
In order to put out any fire you need to remove one of the three elements; either, the fuel, heat or oxygen. Dry chemical fire extinguishers are by far the most common fire extinguishers in the home. They can handle all three types of potential fires found in a kitchen or workshop: combustible solids like wood or paper, combustible liquids like gasoline or grease, and electrical fires. The idea behind a dry chemical fire extinguisher is to blanket the fuel with an inert solid (similar to dirt or sand). A dry chemical extinguisher sprays a very fine power of sodium bicarbonate (normal baking soda), potassium bicarbonate (nearly identical to baking soda), or ammonium phosphate. These solids coat the fuel and smother the fire.
