A verification is a snapshot. Plants change: throughput rises, devices are replaced with other models, test intervals drift with turnaround schedules. A periodic review keeps the SIF and its documents aligned with reality.
Review checklist
- Demands on the SIF in the period versus the demand rate assumed in LOPA.
- Dangerous failures found at proof tests versus the failure rates used.
- Proof tests done on time, with the coverage assumed?
- Bypass hours and spurious trips.
- Device changes, setpoint changes, logic changes since the last review.
- Changes in the process or in occupancy that affect the consequence or tolerable frequency.
Triggers for re-verification
- A device replaced with a different model (new failure rates, SC, type).
- A test interval extended.
- A setpoint or logic change.
- New hazard study findings.
- Field data that contradicts the assumed failure rates.
In First Out AI
Open the saved project, update the inputs and recalculate; the report and SRS draft regenerate with the new date and engine version. Save it as a new project version on the server (paid plans).
Written for First Out AI as engineering guidance. It supports engineering work and does not replace it; check every value against your standards, certificates and company rules with a competent functional safety engineer.