What is a HazOp?

What is a HazOp (Hazard and Operability Study)?

A HazOp is a tried and tested technique for reviewing a process design to identify what hazards might be present (sometimes hidden) in the design.

A HazOp Chair and team

A HazOp would normally be chaired by an experienced chair who is an expert in the application of the technique. The HazOp also relies on the experience and expertise of others present in the meeting – and the success of the HazOp relies heavily on the team assembled to work through the process, under the guidance of the HazOp chair. In large meetings, a HazOp scribe may also be appointed to record the decisions and reasoning behind them – as it can be difficult for the HazOp chair to run the meeting and also keep the notes, hence the need for the scribe.

The HazOp approach

A HazOp will be based on a particular approach (normally agreed in advance of the meeting and recorded and approved in the “Terms of Reference”) which would typically be by analysing a series of “Deviations” from the design intent, to establish the hazards that the process might present. The “Deviations” that are considered are generated by combining process parameters with a series of guide words that ensure the meeting considers a broad range of scenarios – and in so doing would be expected to identify the majority of hazards that arise from certain scenarios.

Identifying the likelihood of hazards

Once the hazards are identified, they can be analysed (and ranked) to establish what the consequences and likelihood of each hazard scenario might be. This information can then be used to establish which hazard scenarios need to be analysed in more detail – typically by way of a Layer of Protection Analysis (LOPA).

The first stage of the Functional Safety lifecycle

While HazOp may be considered to be part of the “Process Safety” of a particular application, it would normally form the first stage of the Functional Safety Lifecycle (as defined by IEC 61511), so the approach to HazOp must recognise the need for verification, functional safety assessment and traceability to later lifecycle phases. The HazOp must be structured so as to allow for (and facilitate) these elements. The HazOp is not an end itself, but part of a broader approach and this must be recognised in the design and documentation of the HazOp.

HazOp Consultancy

=Method can provide expert HazOp chairs and scribes, who will use our tools and templates to deliver a HazOp that is effective, efficient and (as far as is possible) enjoyable. Our approach ensures that the tasks that follow the HazOp (the verification, the functional safety assessment and allocation of safety functions to protection layers) are recognised and supported. =Method can also deliver those follow on tasks if required.

Or if you wish to develop your own expertise in this area, =Method can train and coach you to take on roles in the HazOp yourself.

Contact Method Process Safety

If you have any enquiries about our Process Safety Consultancy services please call us on 01462 713313 or contact us online.

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