Fire extinguisher CO types have the test information stamped on the cylinder, all other types get a sticker on the back of the cylinder. Once dry, the units are recharged. Unlike the UK, the US does not rebuild extinguishers and replace valves at specific intervals unless parts are found to be defective, with the exception of halon. Halon types are often given new o-rings and valve stems at every internal maintenance to minimize any leakage potential. OEM equipment must be used for replacement parts for the extinguisher to maintain its UL rating. If parts are unavailable, replacement is recommended, keep in mind
Fire extinguisher of fire extinguishers: 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 typically used; water and foam extinguishers typically use air. Stored pressure fire extinguishers are the most common type. 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 as common, used primarily in areas such as industrial facilities, where they receive higher-than-average use. They have