(57c) The Study of HAZOP Revalidation Approach

HAZOP evaluation method is used to analyze the risk of the process by the worldwide chemical enterprises and design units. However, Standard Specification for many countries stipulate the enterprise needs to carry on the process hazard analysis once again (revalidating) in several years later. The goal of periodic revalidation is to identify the cumulative changes of risk over time and to improve understanding of risk. The ultimate goal is to avoid accidents. But there is no systematic approach to guide the HAZOP revalidation at present. If we redo HAZOP blindly (performing a new HAZOP similar to the initial one) will only be time-consuming. This paper introduces the concept of HAZOP revalidation which is based on the analysis of the initial HAZOP and discusses many of the factors that need to be considered for the revalidation such as the change management, accident analysis and HAZOP report quality. At the same time，the specific procedure and approach of the HAZOP revalidation are proposed. The panel of experts scoring method is used to determine the revalidating approach and then decides whether to redo or update the initial HAZOP. If the scoring results suggest redo the HAZOP, and then conduct the Hazard and Operability Analysis in accordance with the complete HAZOP procedures; if the scoring results suggest update the initial HAZOP and then modify and supplement previous HAZOP analysis results to meet enterprise current status. This approach is not only time-saving and more targeted which can guide enterprises to conduct better and faster HAZOP revalidation.