Top ten tips for an effective HAZOP (part two)

Simon Burwood gives his tips for an effective HAZOP

Simon Burwood

Following my recent blog, Top ten tips for an effective HAZOP (part one), here are my remaining five tips for an Effective HAZOP.   I’ve accrued these tips during my years at Engineering Safety Consultants (ESC) as a HAZOP chair on what makes a good (and not so good!) HAZOP.  Do you have any other tips to add?


Be clear on what the objectives of the HAZOP review are. It is not a design review. The objective of a HAZOP is to identify hazard and operability issues.

Whatever the issues the team members present, trying to redesign the plant during the meeting due to personal agendas should not be allowed. It’s the responsibility of the Chair to prevent this from occurring.


An experienced scribe allows the Chair to focus on the HAZOP without having to worry over the accuracy of the information being documented. The perfect scribe is able to record what’s being discussed in the room without having to be dictated to. They can aid the Chair by noting suggestions and deferred problems and bringing them up at a more convenient time. We realise that everyone has to start somewhere, but with experience comes perfection! An inexperienced scribe may not reflect what the HAZOP team has agreed, points may be lost and inaccuracies reported. Another important point to be aware of is that the scribe should be familiar with the software being used; if they aren’t, then things go swiftly wrong. Although generally the responsibility of the HAZOP Chair to overview what’s being recorded, continually supervising a scribe could ultimately lead to focus being lost.


For anyone who endures the commute at the end of a long day, or has been stationed in the direct firing line of an over-zealous air-con unit, they can attest to a comfortable environment being a very relevant factor in productivity. HAZOPs can last for months. Disruptive factors can be as simple as the acoustics in the room or the visibility of the worksheets. There needs to be adequate space, a comfortable temperature and noise levels from adjacent rooms considered.


Don’t overdo it! IChemE recommends no longer than six hours a day with regular breaks[1]. They also state that ‘the ideal arrangement is to have no more than three of four sessions a week, each limited to half a day’. Unfortunately, this is often an impractical ideal. Things get missed when fatigue sets in and people generally need to clear their heads or attend to day-to-day work issues which may be distracting them. By providing regular breaks (set within a daily schedule) it allows focus to be kept on the workshop. It’s beneficial to keep people in the room by providing lunch, but of course this is not always practical.  Again, an experienced chair will identify when a HAZOP team is flagging and spot when a dose of caffeine and a stretch of the legs is overdue!


Whilst a word processing package provides a perfectly acceptable means of recording a HAZOP workshop, the benefits of a dedicated software package can provide premium benefits. Although word processing tools allow easy sharing of worksheets, the boon of a dedicated software package (such as – plug alert! – ESC’s ProSET® package), enables easier action tracking, straightforward access to other parts of the HAZOP worksheet, risk ranking and is simple to export into a report.


Once the HAZOP workshop is complete, we can all go home and forget about it.  WRONG!  It’s now time to close out the (sometimes numerous) actions.  The most important thing here is to make sure the action response is adequate and acceptable to the team.  Has the action been assigned to the right person (ideally a HAZOP team member)? Is the justification for closing the action sufficient?  Are the appropriate calculations, models and documents referenced?

Equally important is management of change.  There should be a system in place to make sure any post-HAZOP design modifications are minimized and controlled; do they affect the safety of the plant? Is a follow-up HAZOP required?

To keep the number of final actions down, at ESC we often suggest a “parking lot” list of short-term, often administrative actions that can be closed and incorporated before the end of the study.


If you have any further tips to add, or any comments on my top 10 tips, please feel free comment.

ESC is able to offer Hazard and Operability (HAZOP) and Process Hazard Analysis (PHA) studies as part of the risk analysis process detailed in IEC 61508 / 61511 (Phase 1).

ESC can provide:

  • A HAZOP workshop, led by the HAZOP Chair, providing a highly structured and systematic HAZOP study
  • Use of HAZOP guidewords suitable to the requirements and relevance of the HAZOP study
  • Use of ESC’s bespoke software package, ProSET® PHAComp, offering both accuracy and consistency throughout the HAZOP / PHA process
  • Facilitation of a robust consensus-based decision-making process within the HAZOP Study team, ensuring the important and relevant points are captured
  • A record of the HAZOP study, through the production of a HAZOP report and/or Actions report, detailing the HAZOP study and any requirements taken away from the HAZOP

We offer HAZOP chairs with approval from (not exhaustive): BP, Shell, Chevron, Maersk Oil, Saudi Aramco, BG Group, SEE and more.

[1] Ref. IChemE HAZOP Guide to Best Practice ISBN 978-0-85295-525-3