Safety, Fire & Survival · Fire — Dry Chemical
A dry chemical extinguisher puts out fire primarily by:
- AAdding oxygen
- BCooling the fuel below freezing
- CChemically interrupting the combustion chain reaction✓ Correct
- DSealing the fuel with water
Explanation
Dry chemical agents interrupt the chemical chain reaction of combustion (the fourth side of the fire tetrahedron), giving rapid knockdown of flammable-liquid and some electrical fires. They provide little cooling, so re-ignition from hot surfaces remains a risk if the fuel is not also cooled.
Authority: NFPA; firefighting references
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