If you plan to fit carbon dioxide Category B fire extinguishers in your home, you should be aware of the hazards posed by these extinguishers. Carbon dioxide fire extinguisher hazards are twofold; first, higher levels of carbon dioxide are toxic to humans and can cause death, and second, pressurised carbon dioxide forms dry ice, which can cause damage to skin on contact.
Carbon dioxide fire extinguishers should never be operated in enclosed areas without the use of breathing apparatus. Discharging a carbon dioxide extinguisher in an enclosed area will displace the oxygen, causing a build-up of carbon dioxide. Atmospheric levels of carbon dioxide ranging from 7 per cent upward are toxic to the human body. It may only be a matter of moments before a user becomes unconscious. It is advisable to place breathing apparatus close by carbon dioxide fire extinguishers to use in the event of emergency.
Carbon dioxide under pressure forms dry ice. When using a carbon dioxide fire extinguisher, you should be aware that the plastic horn of the extinguisher will be extremely cold and could freeze your hand, causing damage to your skin. The dry ice is beneficial in firefighting situations, as it will have a cooling effect on the heat of the fire.
Carbon Dioxide Fire Extinguishers
Carbon dioxide fire extinguishers are classified as Category B and can be used on flammable liquid fires, or electrical fires. Carbon dioxide extinguishers are not recommended for combustible material fires such as paper, wood or fabrics. Flammable liquid fires could be fires fuelled by solvents, paints, gasoline, oils or lacquers. Carbon dioxide extinguishers work by taking away the oxygen element that is fuelling the fire.
If you are confronted with an emergency fire situation, your first action should be to ensure the safety of yourself and any other individuals in the vicinity. Only tackle a fire if it is small enough to handle. Portable fire extinguishers are only suitable for use when a fire has just started, as there is insufficient extinguishing agent to tackle large fires. Do not attempt to fight a fire if you are unsure about how to use a fire extinguisher and do not know the basic rules of firefighting or the best way to use a fire extinguisher.
- U.S. Environmental Protection Agency; Carbon Dioxide as a Fire Suppressant, Examining the Risks; Aug. 2010
- U.S. Dept of Labor, Occupational Safety & Health Administration: Extinguishers Basics
- Ohio State University Extension; Portable Fire Extinguishers for Trainers & Supervisors; 2006
- Alabama Cooperative Extension System; Knowing How & When to Use a Fire Extinguisher Could Save Your Life & Property; Nov. 2003