Why is carbon dioxide preferred in fire extinguishers?

Carbon dioxide is preferred in fire extinguishers primarily because it is denser than air. When carbon dioxide is released from the extinguisher, it sinks and displaces oxygen in the air. Since fire requires oxygen to burn, displacing the oxygen effectively suffocates the flames and extinguishes the fire. This mechanism is particularly effective for certain types of fires, especially those involving flammable liquids and electrical equipment, as using water in those situations may not be safe.

The density of carbon dioxide also contributes to its effectiveness; being heavier than air allows it to form a blanket over the fire, further preventing oxygen from reaching it and allowing the flammable materials to cool down.

While there are other types of extinguishing agents, such as water or foam, they may not be suitable in all firefighting situations, making carbon dioxide a versatile and efficient choice for many fire scenarios.