A Hazard Identification Study (HAZID) is most useful when it does more than produce a long list of generic hazards. A good HAZID helps a project team recognise credible threats early, understand how those threats could develop into major consequences, identify existing safeguards and decide what further work is required before the design progresses. For related engineering support, see our HAZID study facilitation.
Guidewords and checklists are valuable because they give the workshop structure without restricting the team to a rigid list. The facilitator uses them as prompts to make sure important hazard categories are considered, while the multidisciplinary team applies project knowledge to decide which scenarios are actually credible.
What is a HAZID study?
A HAZID study is a structured hazard identification workshop commonly used during concept selection, front-end engineering and other early project phases. It can also be used for brownfield modifications, new facilities, major changes, operations reviews and other situations where the team needs a broad view of hazards before more detailed studies are completed.
Unlike a detailed HAZOP, which normally examines process deviations node by node using design information such as P&IDs, HAZID is broader. It may consider process hazards, external events, construction activities, simultaneous operations, environmental conditions, layout, human factors and emergency response. This makes HAZID particularly useful when the design is not yet mature enough for a full HAZOP study.
Common HAZID guidewords
There is no single universal guideword list that suits every project. The facilitator should tailor the prompts to the facility, phase and industry. A practical HAZID guideword set for process and energy projects often includes the following areas.
Loss of containment
Consider leaks or ruptures from vessels, piping, hoses, flanges, seals, drains, vents, temporary connections and loading or unloading systems. The team should think about credible causes such as corrosion, erosion, overpressure, vibration, impact, incorrect assembly, material failure and human error.
Fire and explosion
Review flammable inventories, ignition sources, congestion, confinement, gas accumulation, escalation potential, firewater availability, passive fire protection and separation distances. A HAZID should identify scenarios that may later require detailed fire and explosion analysis, dispersion modelling or quantitative risk assessment.
Toxic or asphyxiant exposure
Where toxic materials, hydrogen sulphide, carbon dioxide, nitrogen or other hazardous atmospheres may be present, consider release locations, occupancy, ventilation, detection, escape and rescue. The team should distinguish between routine exposure risks and major accident scenarios.
High and low temperature
Credible causes of excessive temperature or low-temperature exposure should be identified, including depressurisation, flashing, refrigeration effects, blocked-in liquid expansion, hot surfaces and process upsets. Materials of construction and minimum design temperature can become important follow-up items.
High pressure, vacuum and stored energy
Consider overpressure, vacuum collapse, hydraulic energy, pneumatic energy, rotating equipment, suspended loads and other stored-energy hazards. These scenarios may lead to later work involving relief system design, shutdown philosophy or LOPA.
External events
Typical prompts include vehicle impact, dropped objects, crane operations, bushfire, flood, lightning, extreme weather, nearby facilities, third-party activities and loss of utilities. External events are sometimes underrepresented if the HAZID focuses only on process equipment.
Operations, maintenance and human factors
Review start-up, shutdown, isolation, draining, purging, sampling, maintenance access, lifting, confined spaces, manual handling, temporary equipment and foreseeable operator error. The design should support safe operation rather than rely excessively on administrative controls.
A practical HAZID checklist
A checklist can be used before and during the workshop to confirm that the necessary information and disciplines are available. The following questions provide a useful starting point:
- What hazardous materials and energy sources are present?
- What are the largest credible inventories and release points?
- What operating modes exist, including start-up, shutdown and abnormal operation?
- What external events could affect the facility?
- Are occupied buildings, public areas or neighbouring assets exposed?
- Could one event escalate to adjacent equipment?
- Are emergency access, escape and muster arrangements adequate?
- Are temporary operations, maintenance and construction activities represented?
- What assumptions are being made because the design is not yet complete?
- Which scenarios require follow-up through HAZOP, LOPA, SIL assessment, dispersion modelling or another study?
How should a HAZID worksheet be structured?
A clear worksheet normally records the hazard or initiating event, potential causes, consequences, existing safeguards, risk ranking and recommendations. Some organisations also record affected receptors, major accident event references, responsible action owners and target dates.
The important point is traceability. A reader should be able to understand what the team considered and why a recommendation was raised. Vague entries such as “gas leak” or “fire risk” are less useful than a defined scenario describing where the release occurs, what could cause it and what consequence is being assessed.
HAZID versus HAZOP and LOPA
HAZID, HAZOP and LOPA are complementary rather than competing techniques. HAZID is generally broader and earlier. HAZOP is more detailed and examines deviations from design intent. LOPA is used when the team needs to test whether independent protection layers provide enough risk reduction for a defined scenario.
For a concise comparison, see HAZID vs HAZOP vs LOPA: When to Use Each Study. Where a HAZOP identifies a high-consequence scenario requiring further risk assessment, the next step may be a LOPA study or a functional safety assessment such as SIL assessment and classification.
What makes a HAZID workshop effective?
The quality of the workshop depends heavily on preparation and participation. The facilitator should review the project scope, drawings, design basis and previous hazard studies before the session. The right disciplines should be present, including process, operations, mechanical, electrical, instrumentation, project engineering and other specialists relevant to the facility.
The workshop should also remain focused on credible scenarios. Recording every theoretical possibility can dilute attention from the hazards that matter. Conversely, prematurely dismissing a scenario because a safeguard exists can prevent the team from understanding whether that safeguard is reliable, independent and suitable for the risk.
Using HAZID results through the project lifecycle
HAZID recommendations should feed into the design and later risk studies. Actions may influence layout, equipment selection, isolation philosophy, emergency systems, control philosophy, relief design and functional safety requirements. The HAZID should therefore be treated as an input to the project safety lifecycle rather than a one-off workshop record.
For complex projects, early identification of risk can also reduce rework. Resolving a layout issue or adding a design feature during concept or FEED is usually more efficient than discovering the same issue during detailed design or commissioning.
HAZID facilitation and process safety support
Pro Engineers provides HAZID, HAZOP, LOPA, process safety and functional safety support for projects and operating facilities in Australia. Our approach is to keep workshops technically rigorous, practical and aligned with the maturity of the design.
If you are planning a hazard study or need support defining the appropriate study sequence for a project, contact Pro Engineers to discuss the scope.