DCP fire extinguisher generally cover class ABC Fires. CO2 extinguishers are more effective and specifically designed for indoor use on electrical fires class C fires. Foam extinguishers are most effective on Flammable liquids class B fires. All fire equipment must be serviced annually. DCP extinguishers to be pressure tested every 5 years. CO2 extinguishers are pressure tested every 10 years. Portable fire extinguishers can also be identified by their respective instruction labels they are colour coded.