Safety in the Plant
When a robust Process Safety Management (PSM) audit programme finds no issues, it does not always mean that improvements cannot be made. Conrad Ellison explains.
Wenn ein robustes Prozesssicher-
heitsmanagement (PSM)- Prüfprogramm keine Probleme findet, heißt das nicht immer, dass keine Verbesserungen erfolgen können. Conrad Ellison erklärt.
Lorsqu’un programme robuste de gestion de la sécurité des processus (PSM) ne détecte aucun problème, ceci ne signifie pas toujours qu’aucune amélioration ne peut être apportée. Conrad Ellison nous explique.
Deep in thought T
he purpose of a Process Safety Management (PSM) system is to provide a framework of high level procedures (or risk
control systems), to maintain protective equipment and operations in a healthy state. So, on face value, a PSM audit that
shows year-on-year improvement can be cause for celebration. But what if it is just an indication that performance has reached a plateau? A serious accident could be just around the corner. There are always more improvements that operators could be making to improve process safety performance even further. Often, little thought is given as to
whether the issues explored as part of the audit year after year are even the right ones. If not, you will not see improvements in the number of process safety incidents (PSIs). You are likely to find that leading process safety performance indicators are not consistent with the audit performance, and the lagging indicators are showing a worrying trend with the number of process safety incidents remaining the same or even increasing. One limitation of PSM audits is that
The main differences between the two types of safety audit.
Factor Scope
Objective Focus of audit Method
they are constructed around distinct generic elements, which are audited in turn without considering how they interact with each other. This potential interaction between barriers is often not visible at the PSM audit level. It’s
Regular PSM audit
All PSM system elements
Achieve best practice for individual elements
Suitability of and adherence to written procedures
Check completeness of documents and test experience with system owner and users
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www.engineerlive.com Deep Dive Audit
Major accident hazard scenarios
Ensure specific risk control barriers are working effectively
Weaknesses in plant, process or people aspects of barriers
Verify effectiveness of barriers based on plant records, understanding of staff and field observations
likely that interactions are missed in accordance with the ‘Swiss Cheese Model’ of accident causation. This illustrates that although many layers or barriers of defence lie between hazards and accidents, there can be flaws in each layer that, when aligned, can allow accidents to occur.
Why dive deeper? With this in mind, auditing PSM system elements may not actually identify the potential for a process safety incident. Instead an assessment of specific accident scenarios and verification of specific barriers is required. It’s for this reason that ABB Consulting advises opting for a Deep Dive audit as it can provide assurance that process safety is being managed appropriately. This type of audit does not aim to
replace conventional PSM audits but complement them. PSM audits are still needed to illustrate that the overall systems are being well managed. The Deep Dive audit just takes the process to the next level. It involves making major accident scenarios and their associated barriers the sole focus of the audit. This type of audit is designed to:
n Establish all major accident scenarios n Confirm the basis of safety (BoS) is robust
n Check that the design of barriers allows for the required risk reduction and that they are installed correctly
n Ensure barriers are appropriately maintained and tested
n Confirm workforce competency with barrier management
A Deep Dive audit therefore provides
rigorous assurance that each identified scenario has sufficient barriers that are working effectively. Essentially, it provides an overview of the process safety ‘vital signs’ and ensures that best practice in management systems is being achieved. What does a Deep Dive audit entail?
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