Concept Design Phase Safety Review Focus Areas

The concept design phase is the earliest point at which an organization can influence the inherent safety, operability, and lifecycle risk profile of a facility. Decisions made here process route selection, inventory sizing, plot layout, utility philosophy, and technology choice often determine whether downstream safeguards will be robust and cost-effective or reactive and expensive. A concept design safety review is therefore not a “paper exercise”; it is an intentional, structured effort to embed process safety management expectations into the design basis, identify major accident hazards while the design is still flexible, and establish a credible path for risk management throughout the project lifecycle. In practice, this phase should set the foundation for disciplined risk assessment, including early HAZID screening and the framing assumptions that will later govern HAZOP studies, quantitative risk evaluations, and layer-of-protection decisions.

Read: What is Process Safety Management

Focus Area 1: Define the Safety Basis and Performance Expectations

Before risks can be evaluated, the project must establish what “safe enough” means in operational and regulatory terms. This includes defining applicable codes and standards, corporate risk criteria, and tolerability thresholds for people, environment, assets, and reputation. Confirm the project’s process safety objectives, escalation rules, and decision rights (who can accept risk, who must approve deviations). Capture these in the design basis so later engineering phases cannot inadvertently dilute requirements. A strong safety basis also clarifies expectations for inherently safer design, independent protection layers, and the minimum barrier philosophy for major hazard scenarios.

Focus Area 2: Early Hazard Identification (HAZID) of Major Accident Hazards

Concept design reviews benefit from HAZID workshops because they are broad, fast, and oriented toward “what could go catastrophically wrong.” The emphasis should be on credible, high-consequence events: loss of containment, toxic exposure, overpressure, runaway reactions, fire and explosion, domino effects, and external hazards. The outputs should not be vague lists; they should be structured scenarios with initiating events, potential consequences, existing assumptions, and early recommendations that can still influence process route choice, equipment selection, and layout. A well-run HAZID also flags where specialist studies are needed later (e.g., dispersion modelling, explosion assessment, firewater demand).

Focus Area 3: Process Route and Chemistry Risk Screening

At the concept stage, changing chemistry or process route may be easier than adding layers of protection later. Screen for reactive hazards, incompatible materials, polymerisation, decomposition, dust explosion potential, and thermal stability concerns. Confirm preliminary reaction calorimetry needs and define safe operating envelopes in principle (temperature, pressure, concentration). Inventory minimisation, dilution strategies, substitution of less hazardous materials, and elimination of unnecessary intermediate storage are classic inherently safer approaches that are most feasible during concept selection.

Focus Area 4: Preliminary Risk Assessment and Risk Register Discipline

A concept review should establish a project risk register that is more than a tracker it must be a governance tool for risk management. Rank scenarios by consequence and likelihood using the organisation’s criteria, identify top risks, and define owner/accountability for closure. Ensure each risk has a clear path: eliminate, reduce, control, or justify/accept with documented rationale. This is the bridge between early risk assessment and the project’s ongoing process safety management obligations. It also prevents “recommendation drift” by locking actions to deliverables, due dates, and stage-gate approvals.

Focus Area 5: Safeguarding Philosophy and Future HAZOP Readiness

Concept design is not the time to perform a full HAZOP, but it is the time to make sure a future HAZOP will be meaningful. Confirm the intended control and shutdown philosophy, utilities reliability assumptions, and the boundaries of safety instrumented functions. Identify where independent protection layers are expected, where relief and disposal systems may be required, and what data must be developed before detailed studies (PFD/P&ID maturity, process control narratives, cause-and-effect logic). Poor early definition leads to HAZOP rework and inconsistent safeguards; good early definition enables decisive outcomes.

Focus Area 6: Layout, Separation, and Escalation Control

Plot plan choices can either prevent escalation or hard-code vulnerability. Evaluate separation distances, hazardous area classification assumptions, occupied building siting, access/egress routes, muster point placement, and drainage/containment philosophy. Consider blast and fire exposure, vehicle impact, and critical utility routing. Early layout reviews should aim to reduce the potential for single events to cascade across units, particularly where inventories are large or materials are toxic or highly flammable.

Conclusion

A concept design phase safety review is most effective when it is treated as a strategic risk intervention, not a compliance milestone. By setting a clear safety basis, executing structured HAZID, initiating disciplined risk assessment, and establishing enforceable risk management actions, the project embeds strong process safety management expectations into the design foundation. This approach improves decision quality, reduces late-stage redesign, and ensures that subsequent studies, especially HAZOP, can focus on refining safeguards rather than discovering preventable hazards after key choices have already been locked in.

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