Which type of extinguishers does not require a "verification of service" collar?

The type of extinguishers that does not require a "verification of service" collar is the cartridge-operated dry chemical extinguisher. This type of extinguisher operates using a separate cartridge that contains the expellant gas, which means that, unlike stored pressure extinguishers, the pressure is not maintained within the body of the cylinder. As a result, these extinguishers don’t rely on continuous pressure and do not require the same verification service requirements, such as the installation of a service collar that is typically seen on other types of extinguishers.

Understanding the need for a verification of service collar is crucial in ensuring that improperly maintained extinguishers or those in need of inspection are identified. Other types of extinguishers, especially those that maintain internal pressure, must adhere to more stringent maintenance protocols to ensure functionality, safety, and compliance with regulations set forth in NFPA 10.