Carbon dioxide extinguishers are generally used for

• A. Class A fires
• B. Class B and C fires
• C. Class D fires
• D. Class K fires

Answer: (B)

Carbon dioxide extinguishers work mainly by displacing the air around the fire and forming a dense blanket that smothers the flame. This makes them well suited for fires where the fuel is a flammable liquid or where electrical equipment is involved. Since CO2 does not conduct electricity and leaves no residue, it's a practical choice for small electrical fires and for spills of flammable liquids near electrical gear.

They’re not as effective for ordinary combustibles like wood or paper because CO2 doesn’t cool the material, and the fire can re-ignite once the gas dissipates. They also aren’t appropriate for metal fires or for kitchen oil fires, which require different extinguishing agents. So the best fit is fires involving flammable liquids and electrical equipment.