Initial H&RA identifying hazardous events and required risk reduction per IEC 61511-1 Cl.8
Phase 1 of the IEC 61511 lifecycle is the Hazard and Risk Assessment — the systematic identification of hazardous events and the determination of required risk reduction. It uses HAZOP, LOPA, fault trees, and event trees to establish a defensible scenario set and risk profile before any SIS allocation decisions are made.
Without rigorous Phase 1, all downstream SIL allocations rest on incomplete hazard understanding. Sites that invest in deep H&RA catch the credible-worst-case scenarios that drive SIF design.
Phase 1 produces the hazard register that Phase 2 (Allocation) consumes. It also feeds back to Process Safety Information (PSI) and connects to the broader PHA cycle through 5-year revalidation triggers.
A focused 6-step methodology calibrated to deliver hazard and risk assessment as a working capability — not a documented compliance artefact.
Define unit boundary and gather PSI per OSHA 1910.119(d); align with operating envelope and PHA records.
Run HAZOP per IEC 61882; supplement with What-If / Checklist where appropriate; document hazardous events.
Quantify consequence severity per safety / environment / asset tolerable thresholds; align with corporate risk matrix.
Estimate frequency-consequence pairs; identify scenarios requiring further risk reduction beyond existing IPLs.
Compare residual risk against site-specific tolerable frequency; identify SIF candidates per Cl.9 allocation.
Issue H&RA report with hazard register, required risk reduction, and inputs for Phase 2 SIF allocation.
Decision-gated workflow showing the actual sequence of activities — from initiation through steady-state operation — with key decision points highlighted.
We can scope this element implementation against your facility, regulatory context, and existing management-system maturity — and integrate it with the other Functional Safety Lifecycle Implementation elements you already operate.