Fire Extinguishing Equipment

There are two main types of fire extinguishers, these are stored pressure and cartridge-operated. In stored pressure units, the expellant is stored in the same chamber as the firefighting agent itself. Depending on the agent used, different propellants are used. With dry chemical extinguishers, nitrogen is used, whereas water and foam extinguishers use air. The most common type of fire extinguisher is the stored kind. Cartridge operated extinguishers contain the expellant gas in a separate cartridge that is punctured prior to discharge, exposing the propellant to the extinguishing agent. This type is not common and is used primarily in areas such as industrial environments where they receive higher than average use. They have the advantage of simple but prompt recharge, allowing the user to recharge it and return to the fire in a reasonable amount of time. Unlike stored pressure units these extinguishers use compressed carbon dioxide instead of nitrogen.