Carbon dioxide (CO2) is a colorless, odorless, and chemically inert gas that is both readily available and electrically non-conductive. It extinguishes fire primarily by lowering the level of oxygen that supports combustion in a protected area. This mechanism of fire suppression makes CO2 suppression systems highly effective, requiring minimal clean-up, but should be used in normally unoccupied hazard locations or otherwise avoided by personnel when discharged. CO2 suppression systems may utilize the gas through a total flooding approach but carbon dioxide is also the only gaseous agent that may be utilized through local application. Carbon dioxide may be stored in either high pressure spun steel cylinders (HPCO2 suppression systems) or low pressure light wall refrigerated tanks (LPCO2 suppression systems).
NOTE: Both HPCO2 and LPCO2 systems are equally effective at fighting fires. Neither one is better than the other in terms of extinguishment.