The HAZID sessions are commenced by an explanation of the intended goal for running the HAZID workshop. This is followed by an overview and description, by the designer, of the system to be considered, which must describe the purpose of a system and an outline of its intended operation.
The HAZID workshop thereafter becomes an open session and starts by examining the information in a logical and comprehensive manner, using checklist prompts.
The objectives of the HAZID study are:
- Identify Major Accident Events (MAE) capable of posing a serious and immediate risk to health and safety, including flammable releases, toxic releases, non-process incidents, etc
- Identify the hazards that cause or contribute to causing those MAEs, e.g. process upset, equipment failure, maintenance
- Identify existing engineering or operational controls and measures that are included in the design for prevention or mitigation
- Identify those controls that are safety critical to the identified MAE
- Where appropriate, identify additional prevention and/ or mitigation risk reducing measures (RRMs) for improvement to meet the ALARP Concept
The HAZID should apply the checklist prompts to the various elements within the study to discuss and characterise generic categories of hazard and, if appropriate, define more specific hazard classes. At least the following information should be recorded for each hazard or hazardous activity:
- the potential consequences (e.g. damage, injury/ fatality, physical effects)
- the control and recovery measures in place
- an indication of criticality or severity
- a qualitative assessment of frequency or risk
The same process is repeated for each appropriate hazard category.