Superimposed Backpressure
Superimposed backpressure is the pressure that is on the discharge side of a pressure relief valve (PRV) when the device is required to operate. It is a result of pressure in the discharge system coming from another source. This pressure may be constant or variable. It could be pressure caused by another PRV that is relieving at a lower pressure if the PRV is discharging into a common relief system.
Tags: Valves