Pressure Relief Valves
are designed to protect a pressure system against excessive normal or subnormal pressure in the event of positive or negative excursion of the system pressure. They are required to open at a predetermined system pressure, to discharge or let enter a specied amount of uid so as to prevent the system pressure from exceeding a specied normal or subnormal pressure limit, and to reclose after the normal system pressure has been restored.
Pressure relief valves must also be self-actuated for maximum reliability except where premitted by the applicable Code of Practice for specic applications.
