Designed to provide emergency relief from excessive pressure in refrigerant-containing vessels, they are built in strict conformance with ASME Boiler and Pressure Vessel Code requirements for safety relief devices. Each valve bears the ASME code symbol of certification (UV). Their capacities are rated by the National Board of Boiler and Pressure Vessel Inspectors. These tamperresistant valves are accurately set and sealed by qualified technicians at the factory.