PSV and PRV having many differences between each other in terms of functionality, working, uses, and Purposes. Differences with respect to each parameter will be described step by step in the following sections:

Operation: In normal operations, PRV remains closed and no fluid passes through it. When Pressure rises and exceeds the limit valve opens to protect the system. If PRV fails to reduce excess pressure then PSV pop-up for releasing pressure.

Functionality: When pressure exceeds the set limit pressure, PSV opens suddenly and releases pressure. While PRV passes fluid gradually as per the increase of pressure in the system. PRV does not open suddenly.

Fluid Type: PSV is used to install in the piping system where fluid is compressible, eg: Gases. While PRV is designed to relieve the pressure of the incompressible fluid flow.

Uses: A pressure safety valve is used in Separator, Heater, Scrubber, and filter vessels while a Pressure relief valve is installed to release the pressure of Storage tanks.

Set Pressure: PSV is designed to actuate automatically to release excess pressure while PRV is designed to limit the pressure in a system within a specific set limit.

Set Point: The setpoint of PRV is usually set at 10% above the working pressure limit while in the case of PSV, it is set 3% above the working pressure.

Types: PRVs are divided into pop-type, direct-operated, pilot-operated, and internal relief valves while the pressure safety valve is divided into a wide range according to application and performance.