Safety, Fire & Survival · Fire — Extinguishing Mechanism
Carbon dioxide extinguishes a fire primarily by:
- ACooling the fuel below its ignition point
- BSmothering — displacing oxygen / reducing it below the level supporting combustion✓ Correct
- CChemically inhibiting the chain reaction
- DCoating the fuel with foam
Explanation
CO2 works mainly by displacing oxygen (smothering) with some cooling effect. Foam smothers and cools liquid fires; dry chemical interrupts the chain reaction; water cools. Matching mechanism to fuel is essential.
Authority: NFPA 12; fire theory
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