What is the primary content of an A-B-C (Dry Chemical) extinguisher?

The correct answer is that the primary content of an A-B-C (Dry Chemical) extinguisher is ammonium phosphate. This chemical compound is effective in fighting a range of fires, including those involving ordinary combustibles (class A), flammable liquids (class B), and energized electrical equipment (class C). Ammonium phosphate acts by interrupting the chemical reaction of fire, which is essential for extinguishing flames.

Understanding the classifications of fire extinguishers is crucial for effective fire safety practices. Class A fires primarily involve solids like wood and paper, while Class B fires involve liquids and gases, and Class C fires involve electrical equipment. The versatility of ammonium phosphate allows the A-B-C extinguisher to be used across these different types of fires, making it a common choice for both residential and commercial settings.