It is difficult to learn effectively from projects for many reasons. Despite these difficulties we have learned a great deal in the area of process safety over the past few years as a result of more intense focus on safety both in design and in operation. An example of the increased focus on safety is the increased use of HAZOPs. Almost all process designs are now subjected to one or more HAZOP studies over the course of the project. A HAZOP is a structured method for identifying process design flaws. No such method could ever be perfect. Some design errors will be missed; some problems identified may not be effectively corrected; and some problem "corrections" create new, sometimes worse problems.

This paper applies a structured method to identify cognitive, social and organizational factors which limit the effectiveness of HAZOPs. It is important to consider behavior at these three levels to get a complete picture. At the cognitive level we are interested in why individuals make mistakes and why they resist efforts of others to correct those mistakes (defensiveness). At the social level we need to consider how social interactions, especially those within a design team, impact design effectiveness and defensiveness. Impacts at the organizational level are more subtle and less well understood. The overall organization of a large project will include the operating company, partners, design contractors, construction and installation contractors, vendors, government agencies and others. The processes, procedures, standards and cultures of each of these groups and the interfaces between these groups will impact design decisions and the ability of the design teams to implement changes.

Studying the HAZOP process via a structured method yields new insights into the causes of limited learning in HAZOPs. These insights provide ideas for improving the HAZOP process.

HAZOPs are the last and best line of defense we have for catching design errors and omissions. A significant improvement in the process could provide a step change in the safety performance of process designs.

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