1.0 SCOPE / OVERVIEW
HAZOP and HAZID are qualitative assessment methods to assess and evaluate potential hazards. Whereas a HAZOP (Hazard Operation) review primarily focuses on operational issues, HAZID (Hazard Identification) focuses on identifications of hazards especially with respect to Major Accident Hazards (MAH):
This narrative presents a method in which a hazard Identification (HAZID) review can be performed in a consistent and comprehensive manner.
It is recommended to conduct a HAZID on any project that deals toxic, combustible or flammable material that may cause a potential hazard to the environment or human life.
Items to be evaluated during a HAZID are:
- Layout and segregation/separation with respect to the hazards
- Controls and safeguards to prevent or limit the occurrence of the MAHs
- Mitigating measures to reduce adverse effects of potential of MAHs
- Recovery and emergency response with respect to MAHs
- Escape for credible accident scenarios.
- HAZID - Hazard Identification
- ESD - Emergency shutdown
- PFD - Process Flow Diagram
- P&ID - Piping and Instrument Diagram
- UFD - Utility Flow Diagram
3.0 ROLES & RESPONSIBILITIES
The composition of the HAZID review team is the same as for conducting a HAZOP and consists of:
- Chairman or facilitator - The HAZID chairman (also referred to as HAZID facilitator) should be an independent party with no direct involvement with the project execution. The client must be satisfied that he has the appropriate level of experience in conducting HAZID or HAZOP reviews of similar facilities. The HAZID chairman is to prepare the HAZID report.
- Custodian - The custodian of the HAZID should be a senior/lead engineer. His responsibility to ensure that the HAZID is performed to the applicable standards and good engineering review practices. The custodian is to ensure that the administrative tasks, necessary to perform the HAZID, are being performed e.g., organizing the team, distributing the documentation, bookings and confirming the venue, etc.
- Secretary or scribe - The Secretary should have an appropriate level of experience or training for acting as a HAZID secretary . The Secretary is to attend and minute the HAZID review sessions.
- Follow up coordinator - The Follow-up coordinator, if appointed, can act on behalf of the custodian to facilitate, monitor, and expedite the close-out of recommendations raised during the HAZID review.
- Discipline engineer - The engineer who provides the specialist knowledge and expertise that are essential for a comprehensive conduct of the HAZID review.
- Safety engineer - The safety engineer provides input on safety related issues. Because of his specialist background he also may perform the role of custodian, secretary or follow-up coordinator.
Close out of the HAZID action items requires approval from an appropriate authority (e.g. department head/manager or project manager)
An HAZID team, should comprise between eight to fifteen active attendees, including the chairman, secretary and custodian. With more attendees the meeting may tend to proceed too slowly, with any less, the required expertise may not be at hand. The required expertise (specialist engineers) is to be determined by the HAZID custodian and chairman prior to the HAZID session. It must be communicated and agreed with, by the key team members. For ensuring that the resources are available, the HAZID team may include full and part time members.
Full-time members should include:
- The HAZID chairman
- HAZID custodian
- A process engineer
- An instrument engineer
- Safety engineer
- An operation representative
- Discipline engineers as appropriate
4.1 HAZID Schedule & Information Requirements
The scheduling of an HAZID will depend on the nature of a project and shall be arranged by the Project Engineering Manager and Technical Safety Lead Engineer.
The HAZID review requires the following information to be made available, as a minimum:
- Basis of Design;
- System Design Philosophies;
- Plot Plans, General Arrangements;
- Process flow diagrams (PFD);
- Utility flow diagrams (UFD);
- Procedures relevant the objective of the HAZID.
4.2 HAZID review methodology
The objective is to identify any hazard that could result in the loss of containment, injury to persons or damage to equipment/ structures; assess the conditions which may cause a hazardous situation during normal operation and maintenance, and assess the probability and possibility of equipment failure and the consequential effects on environment, human life and production, and loss of capital.
Findings of the HAZID review meeting, recommendations, and actions should be recorded. Attachment 4.1 HAZID worksheet can be used as a model.
The HAZID meeting will commence with the custodian presenting the objectives of the HAZID, an overview of the systems being under review, and identification of the boundaries of the HAZID. The HAZID will follow a standard approach utilising guidewords. Example HAZID guidewords are presented in Table 4.1; Table 4.2 Can be used as a guide for hazard identification.
The guide word and the event, prompted by the HAZID Chairman, is to be considered by the team to identify:
- Potential hazards associated with the guide word
- Potential risks and consequences associated with the hazard
- Elements of the design, safeguards, or (maintenance/shut down) procedures which prevent or can control the event.
- Actions for mitigating hazards associated with the events if or when they occur.
- Actions needed for safeguarding against consequences of the deviation where no safeguards exist or are considered inadequate
- Parties responsible to complete the actions.
Possible causes include single events, simultaneously occurring events arising from common causation, and events arising from latent (or potential) or un-revealed system or equipment failures.
Causes arising from simultaneous unrelated failures shall be termed "double jeopardy and assumed to occur at such low frequencies that they are not considered "possible” unless detailed frequency analysis or experience dictates otherwise.
All comments made during the review of each node will be recorded by the HAZID Secretary on the HAZID worksheet (e.g. Excel Spread sheet. Refer to Attachment 4.1) These worksheets shall be projected onto a screen, visible to all HAZID participants. A record of the review findings shall be presented in the HAZID notes. All guidewords, events, hazards and risks actually examined (even if subsequently found to be "not a concern") should be recorded. Events, which are improbable or had insignificant potential, may be discarded and identified as “Not a concern”.
4.3 Follow-Up & Close Out
Upon completion of the HAZID, the Chairman will present the findings of the study to a group of Project Representatives selected by the Custodian. The presentation should highlight the recommendations, which in the chairman's opinion; have the potential to impact on safety, operability, cost and/or schedule.
Proposed recommendations are recorded in the HAZID register. It is important to gain agreement during the meeting of the recommendations and also to assign the HAZID actions to someone who can be accountable for the action to be taken.
A report outlining attendees, agreed recommendations and ranked risks is to be issued to the review team. This will enable the review team to gain an understanding of what sort of actions are required and to be taken. The HAZID register to be updated at relevant times during the project lifecycle.
A template for a HAZID is presented as Attachment 4.2