Inspectioneering Journal

Risk Based Method to Establish Inspection Intervals for Pressure Relief Devices

By Philip A. Henry, Principal Engineer II, Risk-Based Inspection & Process Technology Team Leader at The Equity Engineering Group, Inc., Valerie Magyari, Principal Engineer at The Equity Engineering Group, Inc., and D. Baham, Mechanical Engineering and Inspection Superintendent at ConocoPhillips. This article appears in the May/June 2010 issue of Inspectioneering Journal.


This paper describes the API Risk-Based Inspection (RBI) methodology for pressure relieving devices (PRDs) as detailed in the soon to be released 2nd edition of API 581 “Base Resource Document On Risk-Based Inspection.” This methodology has been successfully used at several petrochemical facilities to establish risk-based inspection intervals for PRDs.

The API PRD RBI technology provides a system approach (includes the damage state of the pressure vessels, piping and heat exchangers protected by the PRDs) and evaluates the probability (reliability) and the consequence (criticality) of pressure relief valve failure and sets the appropriate inspection frequency based on risk. Results of recent studies have demonstrated the benefits of the new approach. Compared to a typical API 510 (3) approach, the risk based plan can significantly reduce the overall risk in the plant and at the same time, may provide a significant reduction in inspection costs.

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Comments and Discussion

Posted by Cesar Espinoza on June 7, 2016
Is there a reason for which you are not... Log in or register to read the rest of this comment.

Is the inspection frequency given by RBI valid... Log in or register to read the rest of this comment.

Posted by Valerie Magyari on June 10, 2018
Probability of Leaking was considered:... Log in or register to read the rest of this comment.

Posted by Muhammad Irfan Sultan on August 27, 2019
Thanks for such detailed and well explained... Log in or register to read the rest of this comment.

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