What is HAZID
HAZID is a workshop based qualitative risk analysis technique commonly used for the identification of potential hazards and threats in a process. To conduct a successful HAZID workshop, it is important to involve a multi-disciplinary team familiar with the process and its operation.
The study should be led by an experienced chair, with a scribe to record all identified hazardous scenarios, likely consequences, safeguards, and actions. The effectiveness of the HAZID relies heavily on the experience of the workshop team to ensure that relevant foreseeable scenarios are captured.
Objectives
The objectives of a HAZID are to:
- Review the process at an early stage with a view to ensuring that the process design accounts for credible hazardous scenarios
- Review safeguards included in the design of the process which are designed to mitigate the relevant risk for the identified hazardous scenarios.
Methodology
The HAZID technique, accepted jointly as the most effective techniques for distinctive potential hazards and operability issues, involves the following:
During the hazard identification stage, the criteria used for the screening of the hazards will be established and possible hazards and accidents will be reviewed. For this purpose, the facility will be divided into several sections. Furthermore, the identified hazards will be classified into critical and non-critical hazards. It is of great importance that the hazards considered non-critical are clearly documented to demonstrate that the events in question could be safely disregarded.
This failure case selection will be executed by generating check lists, accident and failure statistics, hazard, and operability Studies (HAZOPs) or by comparison with detailed studies and experience from previous projects.
The HAZID Study team shall neither be over nor undersized. Ideally the study is carried out by a team of 3 to 5 people plus facilitator and secretary. The team should be composed of the following participants:
– the design engineer in charge for the respective facility
– project manager (for new installations)
– plant engineer in charge
– maintenance engineer
– foreman/technician
– facilitator and minute taker
- Execution of the HAZID Sessions
Prior to the HAZID session itself the facility in question will be divided into manageable, logical sections (systems or units). Section limits can be identified for example where there is a significant change in the process conditions, a change in location or in material phase and composition. Sections will preferably be identified in a way that one section contains either gas or liquid, not at the same time. Reasonable divisions of a complex facility can be processing units and less comprehensive facilities could also be sub-divided into functional groups.
