Author IEC 61511 Cl.10-compliant SRS — functional + integrity requirements per SIF
Phase 3 produces the Safety Requirements Specification — the design-grade document that translates Phase 2 SIL allocations into functional and integrity requirements that the FSE team can engineer. Per IEC 61511 Cl.10, the SRS covers process safety time, demand mode, safe state, response time, environmental conditions, and proof-test interval.
A complete SRS catches design ambiguities before they become commissioning rework. Sites with rigorous SRS practice see 50% lower SIS commissioning issues and substantially fewer FSA Stage 2 audit findings.
Phase 3 is the formal hand-off from process safety (Phases 1-2) to functional safety engineering (Phases 4+). The SRS is the contract between hazard study and design.
A focused 6-step methodology calibrated to deliver safety requirements specification (srs) as a working capability — not a documented compliance artefact.
Receive SIL allocation register; baseline SIF inventory with SIL targets, demand mode, and PHA traceability.
Author per Cl.10.3 — measurement parameter, trip setpoint, voting, time-to-action, final-element action, reset philosophy.
Specify PFD/PFH allocation, HFT, SFF, diagnostic coverage, common-cause factor per Cl.10.3.14-18.
Calculate PST from process upset to dangerous consequence; budget response time per SIF with sensor / logic / final-element shares.
Process + instrumentation + operations + HSE review per Cl.10.3; capture deviations and resolution.
Issue baselined SRS; hand to Phase 4 SIS design; integrate with MOC for any subsequent change.
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.