The Safety Selector Valve is designed specifically to function as an effective ‘switch-over’ device that permits routine or emergency servicing of redundant pressure relief devices with no process interruption, providing continuous system over-pressure protection.
Until recently, bulky and expensive piping fabrications or total shutdown were the only methods for safely
servicing the pressure relief devices. These systems required either two separate vessel penetrations with
mechanically linked block valves or a 3-way block valve that commonly resulted in high inlet pressure loss, excessive turbulence to the active pressure relief device and multiple leak points. The Safety Selector Valve solves these problems. It is easy to install, requiring only one vessel penetration in the same size as the pressure relief valve inlet. The unique design provides less than 3% pressure drop to the active pressure relief valve inlet when used with the largest API orifice available in a given valve size, in accordance with API RP520, Part II and ASME Section VIII guidelines.