FUNCTIONAL SAFETY SERVICES
HAZOP / HAZID
STUDIES
Identify hazards early. Strengthen your design before risk becomes operational reality.
Every high-consequence industrial facility, process system, or packaged unit starts with one practical question: what could go wrong, and what does it take to prevent it?
That question is more complex today than it was a decade ago. Process plants, energy systems, and manufacturing environments now operate with digital control architectures, SCADA systems, and networked PLCs at their core. A hazard scenario that once stopped at the valve or sensor boundary can now propagate through a control system, travel across a network segment, or interact with a cybersecurity vulnerability in ways that traditional HAZOP teams were not structured to evaluate.
HAZID and HAZOP are structured, engineering-led studies that help your team answer the hazard question before it becomes an incident, a rework cycle, a schedule delay, or a compliance gap. Arista Cyber supports organizations in identifying and evaluating process hazards, including loss of containment, overpressure, temperature excursions, flow deviations, utility failures, control system anomalies, human and operational errors, and credible escalation paths.
Whether you are designing a new plant, upgrading an existing unit, integrating a new package system, or planning a turnaround modification, these studies provide a disciplined way to challenge assumptions and confirm that safeguards are sufficient across both the physical and digital layers of your operation.
HAZID (Hazard Identification)
A HAZID study is a high-level hazard review used early in the project lifecycle. It is most effective during concept selection and early design, when changes are less expensive, and decisions are still flexible. HAZID surfaces major hazards, risk drivers, and operational concerns before design intent hardens and before digital control architecture choices become locked.
HAZID typically addresses:
- Major process hazards and potential accident scenarios
- Site and layout-related hazards, including interfaces, access, congestion, and siting
- Utilities and infrastructure dependencies, including digital communications and control power
- Human factors and operational constraints at a high level
- Control system and instrumentation interfaces where cyber-physical risk intersects
- Key recommendations that feed into later HAZOP and SIL determination activities
HAZOP (Hazard and Operability Study)
A HAZOP study goes deeper. It uses a structured guideword method to identify deviations from design intent and evaluate their causes, consequences, existing safeguards, and required actions. It is typically performed when the design is mature enough to be challenged meaningfully, often at the PFD or P&ID stage, and it is a core activity in process safety management under IEC 61511 and IEC 61508.
HAZOP typically addresses:
- Deviations such as No Flow, More Pressure, Reverse Flow, and Less Temperature
- Credible causes include equipment failure, control loop faults, human error, utility loss, and instrumented system failure
- Consequences covering process upset, release, escalation, equipment damage, and safety impact
- Existing safeguards, including instrumented functions, alarms, relief devices, and operating procedures
- Recommendations and actions with owners, priority levels, and rationale for closure
- Control system and software-related deviations where applicable, including spurious operation and loss of signal integrity
Our HAZOP and HAZID studies are structured to align with and support compliance activities under:
- IEC 61511 – Functional safety: Safety instrumented systems for the process industry sector
- IEC 61508 – Functional safety of electrical, electronic, and programmable electronic safety-related systems
- ISO 26262 – Road vehicles functional safety (where applicable for automotive and mobility clients)
- ISA/IEC 62443 – Industrial automation and control systems security (informing cyber-physical hazard identification)
Where outcomes feed into SIL determination or LOPA, study documentation is structured to support those downstream activities without rework.
A practical rule: run HAZID early to shape the project, and HAZOP when the design can be meaningfully challenged.
Common triggers include:
- New facility design, brownfield expansion, or major process change
- Packaged equipment integration where interfaces and control intent require scrutiny
- P&ID freeze and pre-commissioning preparation
- Turnaround modifications, tie-ins, and control system changes
- Digital transformation projects introducing new networked OT components or remote access capability
- Incident learnings that require a systematic review of hazard scenarios
- Regulatory or internal assurance requirements under IEC 61511 or equivalent
We treat HAZOP and HAZID as a genuine risk-reduction exercise, not a documentation formality. That means focused preparation, disciplined facilitation, and outputs that engineering and operations teams can act on.
Preparation and Scope Definition
We confirm the scope, nodes, boundaries, and engineering basis. This includes reviewing available design documents, aligning on operating modes and interfaces, and identifying where digital control architecture intersects with the physical hazard boundary.
Structured Workshop Facilitation
We run focused sessions with the right discipline mix. Depending on the study, this includes process engineering, operations, instrumentation and controls, mechanical, electrical, maintenance, HSE, and project leadership. Where control system or OT network components are in scope, we bring the technical context to interpret deviations accurately. Sessions stay disciplined, evidence-led, and aligned to design intent.
Practical Documentation and Action Management
We capture deviations, causes, consequences, safeguards, and recommendations clearly. Actions are written in operational terms with ownership and priority so they can be tracked through closure and audited with confidence.
Integration With the Safety Lifecycle
Where required, outcomes are structured to support later activities, including SIL determination, LOPA, Safety Requirement Specification (SRS) development, commissioning checks, and ongoing functional safety management. This avoids duplication and keeps the safety case coherent across lifecycle phases.
- Early identification of process and operational hazards before they become design defects or operational surprises
- Better design decisions through structured challenge of assumptions, interfaces, and control system boundaries
- Reduced rework and stronger project execution by resolving risk issues while changes are still manageable
- Improved safeguard clarity across alarms, interlocks, relief systems, procedures, and operator response expectations
- Clear input for SIL determination, LOPA, and SRS development through structured hazard scenarios and safeguard context
- Audit-ready documentation that supports compliance with IEC 61511, IEC 61508, and internal governance requirements
- A disciplined record of hazard decisions that supports ongoing safety management and future modifications
- HAZID or HAZOP report with a clear structure and full traceability
- Node list and methodology summary
- Deviation register with causes, consequences, safeguards, and recommendations
- Action list with owner, priority, rationale, and suggested closure approach
- Summary of high-consequence scenarios and critical safeguards
- Inputs structured for SIL determination and LOPA, where applicable
- Integration notes for SRS development and commissioning verification
Most functional safety teams approach HAZOP as a process safety exercise. We approach it as a process safety and cyber-physical risk exercise. That distinction matters in industrial environments where PLCs, DCS platforms, safety instrumented systems, and OT networks are part of the hazard boundary.
- Dual competence in functional safety and OT/ICS security: our team understands both what IEC 61511 requires and how digital control systems fail in practice
- Strong facilitation that keeps sessions focused on risk, not debate, with a clear rationale behind every recommendation
- Practical outputs that respect operability constraints and site realities, not just textbook compliance positions
- Lifecycle thinking: every study is documented to support what comes next, whether that is SIL assessment, SRS development, or FSA preparation
- Deep operational experience across high-consequence sectors, including oil and gas, energy, pharmaceuticals, and process manufacturing
Ready to Start Your HAZOP or HAZID Study?
We do more than document hazards. We help teams understand what matters most, where safeguards are weak, and which actions reduce risk in a meaningful way.
Reach out to our functional safety team. We will confirm the scope, lifecycle stage, workshop plan, and the outputs your stakeholders need for confident, defensible risk decisions.