HAZOP Revalidations
When it comes to revalidating HAZOPs, there are usually a lot of questions. Why does the HAZOP need to be revalidated even if there are no changes made to the process? When is the right time to do a revalidation? How do you execute a HAZOP revalidation efficiently?
All of these are great questions, and it's important to know that even if nothing in the process has changed, HAZOP revalidations are important to carry out over the lifecycle of an asset. In fact, even if HAZOPs are performed with every Management of Change that is implemented to manage the risk, HAZOP revalidations are still necessary. Depending on the process safety maturity of a company, there may have been undocumented changes that would change the risks identified in the initial HAZOP and introduce new hazards. Additionally, the collective of all process changes since the initial HAZOP could introduce new hazards that were not identified or considered credible during the evaluation of a single MOC. Finally, certain countries even have regulatory requirements to perform a revalidation HAZOP within a specified timeframe.
There are a number of other reasons why a revalidation HAZOP is valuable, including:
The quality of the previous HAZOP is not up to standard due to lack of knowledge or experience of the initial HAZOP team
The increased knowledge and experience from an operations background may bring new information from additional years of operation such as any incidents that have occurred that may make certain scenarios more likely
Confirmation of completion of previous HAZOP recommendations
Changes in regulatory and company requirements that were not considered in the initial HAZOP
Decommissioning of process equipment that may introduce new hazards that were not present during normal operation
Staffing changes that may impact the occupancy of the facility and the response time for alarms
Changes to the company PHA standards or risk matrix
Although this is not an exhaustive list, there are many contributing factors as to why a revalidation HAZOP is valuable.
There are also several approaches to conducting a revalidation HAZOP. Determining which method to choose depends on the quality of the initial HAZOP, the effectiveness of the Management of Change system and the level of involvement of company employees.
Updating: Requires a high quality initial HAZOP and a strong MOC system. The initial HAZOP will be updated to incorporate any changes made to the process and any incidents that have occurred
Evergreen: Requires a high quality initial HAZOP, a strong MOC system and continuous updating of the HAZOP. The initial HAZOP is continuously updated with each MOC to create a real-time HAZOP. During each revalidation, a team will ensure that no changes were missed and evaluate the effects of the combined changes
Redo: Completing the revalidation HAZOP as an initial HAZOP. This is typically done if the quality of the initial HAZOP was poor or extensive changes (to the process, regulatory requirements or company policies) would be difficult to capture through the updating method.
The on-going requirement for HAZOP revalidations underscores the importance of ensuring a high quality initial HAZOP and a strong MOC process to minimize the effort and the amount of redo approaches that are needed for revalidations.