Safety in the Plant
Stage 1 – Understanding. Hazard analysis reports such as HAZID and HAZOP reports must be reviewed to identify major accidents and the required barriers. From this, a range of high-
risk scenarios for the detailed Deep Dive audit can be established. A broad range of event types need to be selected to enable the assessment of different types of prevention, control and mitigation barriers.
Stage 2 – Verification and field visit. Verification is then sought for the effective functioning of each scenario and its associated barriers. There are three foci to this stage: barrier verifications; processes; and the people operating them. Experience has shown that the best
results can be obtained by deploying two process safety specialists as assessors; one with a PSM systems and operations background and the other with a plant engineering and asset integrity management background. It’s also important to tap into
the knowledge of on-site process engineers, operating managers and maintenance engineers. This helps with the understanding of major accident scenarios and ensures that the audit team can efficiently locate key information. An essential part of this process is conducting a field visit that focuses on verifying specific barriers. To start, the barriers are visually checked to ensure that they are in good condition and have been installed as per design. ABB finds that photos of any deficiencies are an excellent way of providing high-impact evidence to site management. Following on from this are discussions
about the barriers with operators and maintenance technicians. This tests their understanding of the potential for major accidents on the site and their role in maintaining the barriers. It can be an indication of complacency when it emerges that operators are unaware of the emergency procedures necessary for preventing the escalation of incidents.
management is to prevent process incidents from occurring.
A
Stage 3 – Reporting. The audit report provides details of the assessment for each barrier, along with a decision on whether the barrier is working effectively or whether a related weakness needs to be addressed. This could relate to the plant, processes or people involved.
Conclusion A prime concern in process safety management is to prevent process incidents from occurring. Therefore it makes sense to devote some assurance effort directly to the scenarios themselves, focusing on the specific risks and layers of protection.
T
he Deep Dive audit takes the process safety management to the next level. It involves making major accident scenarios and their associated barriers the sole focus of the audit.
A Deep Dive audit of key process incident scenarios can be a very direct and cost-effective way to provide assurance that process safety is being managed appropriately. It complements audit-based assurance processes and enhances an organisation’s PSM audit and review programme. That is not to suggest that auditing of the PSM system is not a necessary or effective tool. It just needs to be accompanied by an approach that takes process safety even further and provides operators with a high degree of confidence that barriers are working effectively. n
Conrad Ellison, principal safety consultant, ABB Consulting UK
prime concern in process safety
Conrad Ellison is principal safety consultant at ABB Consulting UK, based in Teeside, UK.
www.abb.co.uk/consulting
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