A carbon dioxide extinguisher used on electrical installation fires should not be used in a confined space as the user could be overcome and be asphyxiated deprived of air. D - flammable metals. Guide To Which Fire Extinguisher To Use Fire Class A B Abc K Fuel Sources Extinguisher Fire Extinguisher Portable Fire Extinguisher A dry chemical fire extinguisher might be the best choice for confined spaces. . A - wood paper trash. Do not use CO 2 extinguishers for Class A fires because the fire may continue to smolder and re-ignite after the CO 2 disperses. CO2 fire extinguishers are not safe in confined spaces as they displace oxygen. A - wood paper trash. The main fire extinguishers to avoid when in a confined space are CO 2 and dry powder extinguishers. Water water mist water spray foam dry powder standard dry powder specialist carbon dioxide CO2 and wet chemical. What fire extinguishers shouldnt be used in ...