Carbon Dioxide (CO2) is used on Class B (flammable liquid) fires. CO2 is safe to be used on live electrical fires. CO2 fire extinguishers are available in a variety of sizes with light weight aluminium cylinders.
Advantages: Carbon Dioxide leaves no residue, is safe for use on fires involving energized electrical equipment, and is effective on fires in locations such as semi-sealed enclosures, which cannot be readily penetrated by non-gaseous extinguishants. It is the preferred extinguishant for use for in electronic environments.
Disadvantages: Carbon Dioxide has very poor ‘knock-down’, short discharge range and is almost totally ineffective in the presence of significant air movements. Because it displaces oxygen, atmospheres containing enough carbon dioxide to extinguish a fire do not contain enough oxygen to support life and could kill by asphyxiation. The carbon dioxide fire extinguisher discharges forming a cloud of very cold gas and some solids (dry ice). It produces a loud noise during discharge that may startle inexperienced operators.