HAZOP technique

The HAZOP technique was originally developed almost 40 years ago and is now the most familiar method to identify and manage hazards on process plants worldwide. Even though hazard identification is the key focus, operability problems should be identified to understand if they have the possibility to result in process hazards.

HAZOP is applied to identify:

  • Hazards – the ways in which a system can fail leading to injury or damage
  • Operability – the ways in which a system can fail to perform its intended function

The success or failure of the HAZOP study depends on several factors:

HAZOP study emphases on specific sections of the process named “nodes”. Usually the nodes are identified from the P&ID of the process before the HAZOP commences. A process parameter is taken into consideration and an intention is generated for the associated node. Then a sequence of guidewords is used with the parameter to form a deviation. The procedure is repeated for the subsequent deviations and it continues untill the particular node is finished. The focus is then changed to the following node and the procedure is repeated.

Because of the very comprehensive and brain-storming approach, HAZOP study requires an extensive and dedicated team throughout the period of the study and the team should have representatives from multiple disciplines and Chaired by an experienced facilitator with thorough Process Safety knowledge. An ideal HAZOP team should include a third-party Process Safety Specialist since more hazards and operability issues are likely to be recognised while using an outsider’s perspective with no vested interest in the company’s operations or performances.


  • The entirety and accuracy of drawings and other data used for the study
  • The technical expertise and insights of the team
  • The skill of the team to visualise and predict deviations, causes, and consequences
  • The capability of the team to focus on the more severe hazards among the other hazards recognised

Our knowledge

The Process Safety experts of Sigma-HSE have impressive portfolio of successes in chairing HAZOP studies to clients worldwide. Sigma-HSE offers services by providing a Chair and a Scribe to involve with client’s team to carry out the HAZOP more proficiently.

Get in touch

Sigma-HSE have a dedicated and experienced team of process safety specialists wth a passion for safety. Please call on +44 (0)1962 840570 to discuss your process safety concerns with Mike Weaver our Technical Manager

Contact us