Pressure Relief Valves

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 tamper-resistant valves are accurately set and sealed by qualified technicians at the factory. POP-EYE will be standard on all H56xx series valves beginning with the H56xx”R” series in July 2019. All other H56xx series valves will become standard with POP-EYE by August 2019.

Hansen pressure-relief valves help meet the requirements of ANSI/ASHRAE 15 Safety Standard for Refrigeration Systems as well as other worldwide codes. This standard requires pressure vessels of all refrigeration systems to be protected by a pressure-relief device or other approved means to safely relieve pressure in the event of fire or other abnormal conditions. Once installed, a properly selected Hansen pressure-relief valve is ready to vent to atmosphere any temporary excessive overpressure inside of a vessel. After discharge, these valves will attempt to reseat to minimize loss of refrigerant. However, once any relief valve has discharged, it must be replaced as soon as possible because debris may have settled on the seat during discharge. Hansen pressure-relief valves should be connected to the vapor space of refrigerant vessels, heat exchangers, oil pots, oil stills, pilot receivers, and elsewhere as may be required by various codes. Where dual pressure-relief valves are required, Hansen offers the three-way valves and other components necessary for assembly; see page 4. Rupture disc assemblies are required when using Hansen pressurerelief valves for halocarbon applications because the high cost of such refrigerants demands extreme tightness, see bulletin K209. Also, see Bulletin K129 for information on the EZ-SRV Relief Valves. These pressure-relief valves offer a cartridge style design for ease of replacement without disturbing the piping. EZ-SRV pressure-relief valves are available in pressure ratings to 600 psi (matching the H5600 “R” series capacities through 400 psi). Liquid relief valves are also available in the EZ-SRV series. EZLQ relief valves are designed and rated for liquid applications.