How Does a Fire Extinguisher Work?

Different extinguisher types target fires in different ways. Water extinguishers cool the burning material below its ignition point (removing heat). CO₂ extinguishers displace oxygen around the fire and cool it simultaneously. Dry-chemical extinguishers (ABC powder) release monoammonium phosphate, which melts and coats fuel surfaces to cut off oxygen and interrupt the chemical chain reaction. Foam extinguishers blanket liquid fuel fires with a film that smothers flames and prevents re-ignition. Inside the cylinder, the agent is stored under nitrogen or CO₂ pressure — typically around 12–14 bar — which propels it out when the valve is opened.