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 extinguishers have a projected service life of about 25–35 years, although many are of such quality that they can outlast this, but realize that science is ever-changing, and something that was the best available 30 years ago may not be acceptable for modern fire protection needs. Fire extinguishers are sometimes a target of vandalism in schools and other open spaces. Extinguishers are occasionally partially, or fully discharged by a vandal, impairing the extinguisher's actual fire-fighting abilities. In open public spaces, extinguishers are ideally kept inside cabinets that have glass that must be broken to access the extinguisher, or which emit