Hazard identification is the first and most critical step in risk management. You cannot control a hazard you have not identified. HAZID (Hazard Identification) and HAZOP (Hazard and Operability Study) are structured, team-based techniques for systematically identifying hazards and operability problems before they result in incidents.
Why This Exists
Unidentified hazards cannot be mitigated. HAZID and HAZOP provide structured methodologies that use team expertise and guidewords to surface hazards that might be missed by individuals working alone. The structured record produced by a HAZID/HAZOP study provides documented evidence of the risk assessment process.
Who This Is For
- Safety engineers facilitating or contributing to HAZID/HAZOP studies
- Operations managers commissioning and reviewing hazard studies
- Project engineers providing technical input to hazard identification
- Auditors reviewing the completeness of risk assessment processes
HAZID: Hazard Identification
Purpose
HAZID is a high-level, broad-scope study performed early in a project to identify all significant hazards associated with an operation, facility, or system. HAZID produces a register of hazards that is then carried forward into more detailed risk assessment.
Process
- Assemble the team — Multi-disciplinary team with relevant expertise (operations, engineering, safety, environment)
- Define the scope — What operation, system, or facility is being studied?
- Apply guidewords — Systematically work through hazard categories (e.g., fire, explosion, toxic release, struck by, loss of buoyancy)
- Identify causes and consequences — For each hazard, what could cause it and what are the consequences?
- Assess initial risk — Estimate likelihood and severity without controls
- Identify existing controls — What safeguards are already in place?
- Assess residual risk — Risk with existing controls applied
- Identify actions — What additional controls or studies are required?
- Record findings — Capture all findings in the hazard register
HAZID Guidewords for Subsea/Diving Operations
Personnel hazards:
- Drowning / entrapment
- Struck by (dropped objects, vessel, equipment)
- Caught in (entanglement, rotating machinery)
- Decompression sickness
- Gas toxicity
- Thermal stress (hypothermia, heat stress)
Equipment hazards:
- Loss of pressure integrity (vessel, chamber, umbilical)
- Loss of lifting equipment integrity
- Fire / explosion
- Electrical hazard
Environmental hazards:
- Adverse weather / sea state
- Strong currents
- Poor visibility
- Marine life (stinging, biting, entanglement)
HAZOP: Hazard and Operability Study
Purpose
HAZOP is a more detailed, systematic technique applied to specific processes, procedures, or systems. It uses structured guidewords applied to process parameters to identify deviations from design intent and their potential consequences.
Process
HAZOP applies guidewords to process parameters at defined nodes (specific points in the process or system):
| Guideword | Meaning |
|---|---|
| No / None | Complete negation of design intent |
| More | Quantitative increase |
| Less | Quantitative decrease |
| As well as | Qualitative increase (additional component) |
| Part of | Qualitative decrease |
| Reverse | Logical opposite |
| Other than | Complete substitution |
Application to Diving Operations
For a surface-supplied diving operation, a HAZOP might examine:
- Gas supply node: No flow (supply failure), more flow (regulator failure), wrong gas (incorrect mixture connected)
- Umbilical: Loss of integrity, entanglement, excess tension
- Communication: No communication, degraded communication, communication to wrong diver
- Depth/pressure: Greater than planned depth, less than planned depth, rapid pressure change
Documentation Requirements
Hazard Register
The output of a HAZID/HAZOP study is a hazard register containing:
- Hazard number and description
- Causes
- Potential consequences (severity, affected parties)
- Existing controls
- Risk rating (with and without controls)
- Additional actions required
- Action owner and target date
- Close-out status
Traceability
All hazard identification studies must be traceable:
- Document who participated, when, and what scope was covered
- Studies must be reviewed and updated when operations change significantly
- Actions must be tracked to close-out with evidence
Integration with Risk Management
HAZID/HAZOP outputs feed into:
- Operational Risk Models — Hazards are inputs to formal risk models
- ALARP Principles — Controls identified must be assessed for ALARP
- Dive Planning & Risk Assessment — Operation-specific hazard assessment