Hazard and Operability Analysis (HazOp)
HazOp is a structured and systematic technique for system examination and risk management, based on the theory that risk events are caused by deviations from the design of the operating intentions or limits.
HazOp uses brainstorming in order to be an effective qualitative risk assessment tool and provide an inductive risk assessment technique (bottom-up). It deals with the perspectives of design, physical constrains, operational factors and procedural issues.
HazOp is structures in by dividing the system into components parts (nodes). After each node a series of guidewords are applied to identify the consequences (if the guideword did not occur). Guidewords differ by industry and by process/ department, but as long as they are predefined and standardised, no problem exists.
The process comprises of 4 steps:
- Definition – Set objectives of the process, assign responsibilities, build the teams
- Preparation – Plan, collect data, set a timeframe and schedule the process
- Examination – Divide the system, identify deviations, identify consequences, identify significant problems, identify protections, create measures and repeat until all areas and components are covered
- Document and follow-up – close the process loop by recording the steps, producing and signing the report, reviewing and following-up of the progress and re-examining the process
- Helpful for hazards that are difficult to quantify
- Systematic and comprehensive
- Simple and intuitive process
- No means to assess hazards arising from interactions of different parts
- No risk ranking or prioritisation
- No means to asses effectiveness of controls