The periodic verification of the relief system design and design basis is good practice, but does not mean an operator must re-perform the Pressure Relief Analysis (PRA) at each cycle.  Similar to the verification of Process Hazard Analyses, a streamlined approach to verification of the PRA is advocated when an operator has put processes in place to maintain the relief system design basis in response both to changes within the facility as well as to internal and external learnings.  This Revalidation encompasses three main elements of evaluation:  Baseline, Capability, and Effectiveness.  The objective of the baseline assessment is to identify the potential for systemic weaknesses in the PRA that may pose significant risks to operations yet may not be revealed as part of the evergreening process evaluation, while the capability and effectiveness assessments are geared towards evaluating those evergreening processes.  By having an appropriate program in place, the PRA Revalidation can be a cost effective solution to the periodic verification of the relief system design and design basis, while still driving continual improvement in both the relief system design itself and the processes used to maintain that design basis.

Read more in our white paper Pressure Relief Design Basis Revalidation, which contains not only the details for implementing the Revalidation process, but also a case study illustrating lessons learned.