A Prudent Approach to Revalidating Process Hazard Analysis

The Chemical Process Industry (CPI) has long recognized the necessity of periodically revalidating Process Hazard Analyses (PHAs), such as Hazard and Operability Studies and What-if analyses. CCPS has published a book which describes this work process titled Revalidating Process Hazard Analyses. However there is limited guidance for revalidating supplemental risk analyses. The objectives of performing periodic revalidations are to address the cumulative changes in risk that occur over time and to continuously improve our understanding of that risk. The ultimate goal of any Process Hazard Analysis is to avoid incidents.

 The purpose of Process Hazards Analysis (PHA) is to identify and understand the hazards associated with the process being reviewed, to understand the potential resultant hazardous events, and to prevent those events by identifying all the potential routes to those events and ensuring that adequate safeguards are in place to mitigate their risk. The application of a suitable hazards evaluation methodology (e.g., Hazard and Operability [HAZOP], Failure Mode and Effect Analysis [FMEA], What If, Checklist) is a core process of the PHA. All of the most-used methodologies are ultimately just different ways of asking “What If” questions. The key to success is asking (and, of course, correctly answering) the “right” What If questions. This paper will look at how a variation on an old theme can significantly improve the likelihood of asking all of the right questions, in a way that capitalizes on the strengths of some of the other approaches while avoiding their weaknesses. The work process mentioned in this paper will be illustrated with actual field examples and case studies.

This paper will guide PSM managers, Health and Safety (HS) managers, Process Hazard Analysis team leaders in effective preparation before and during a PHA meeting and thereby can reduce the total PHA resources hours required. The work process furnishes a company with an effective tool for revalidating a Process Hazard Analysis that will not only be in compliance with regulation, but will provide a basis for maintaining process, production and facility equipments in a reliable and safe operating condition.