CO2 (Carbon Dioxide) fire extinguishers are the only fire
extinguishers recommended for fires involving electrical equipment.
CO2 is safe to use on and around electrical equipment, as the gas
itself is non-conductive, and once used, there is no sticky foam or
messy powder left behind. They are also effective on Class B fires
Carbon dioxide fire extinguishers are painted bright red with a
black panel above the operating instructions. They have a
distinctive horn-shaped nozzle at the side on the smaller models
with 5 kgs and above having a hose and horn. CO2 fire extinguishers
should not be used on Class D fires, involving flammable metals.
The CO2 gas can react with some volatile metals, and as with other
non-D rated extinguishers, can also blow burning metal over a wide
area, making the situation worse. CO2 extinguishers are the most
popular with film units, due to the low secondary damage caused
when used. If paired with a foam extinguisher, 4 out of 5 fire
categories are covered.