The PSV That Did Not Fail—Misconceptions About PSVs


  • This article was originally presented at the 8th Global Congress on Process Safety, Houston, TX, April 1–4, 2012 (for correspondence)


Pressure relief devices generally represent the last line of defense for a pressure vessel in a chemical plant during abnormal situations. The article title comes from the numerous times the author heard that “a pressure safety device had failed” when the person making this statement was in essence thinking that “the pressure safety device had opened.” The use of the term “failure” conveys the impression that something was wrong about this safety device, when in fact it had done exactly what it was supposed to do. And although the consequences of the device activation may cause an undesirable event such as plant shutdown, it is not a relief system failure. Some misconceptions are so widely spread among plant engineers that it is very hard (especially for young engineers) to challenge and deviate from that common “knowledge.” It is not the goal of this article to provide in-depth design considerations for pressure safety devices. The objective of this article is to present some key points that “every plant engineer should know” about the pressure safety valve lifecycle, from design to installation and maintenance. © 2013 American Institute of Chemical Engineers Process Saf Prog 32: 84–89, 2013