Isolated Relief Valve


Over pressure in an isolated PSV or downstream pipework:

A short case study looking at the potential to create an over pressure scenario in the relief valve or downstream piping of an isolated dual system PSV.  (3 min video below)

I am very grateful that the original author of the case study Robin Smith has taken the time to review the video and provided corrections, comments and recommended the addition of a further graph.

Please leave a comment below, I would appreciate as much feedback as possible.

About: Brett Mahar is Owner and Director of Process Safety Verification. His passionate about producing the highest quality training content for process safety and over pressure protection. He is the developer and presenter of the online training course “How Teams Can Avert High Potential Hazardous Incidents (Over Pressure Protection)”. Brett sends out regular videos looking at different aspects of over pressure protections, if you would like to subscribe then click here



3 Responses to Isolated Relief Valve

  1. Robin Smith says:

    Did you say “Let’s take a closer time”? How about “a closer look”?
    The chart of pressure drop across the PSV is only right in the flowing case where downstream is not blocked. Then, the pressure rises back to the same as upstream, showing why the problem is more acute than it seems in the video. Maybe you could adapt it to show this accurately?

  2. Robin Smith says:

    The valves are dual, not duel – check the first paragraph text.
    You state the pressure as locked in upstream, but it is downstream of the PSV and its spec change that the problem occurs, not upstream, where the rating is adequate.

  3. admin says:

    Robin, as the original author of the case study thank you for taking the time to review this training video. I will of course re-record with the corrections/changes you have mentioned.
    Thanks again. Brett Mahar

Comments are closed.