Operation and Maintenance
We manage proof testing, repair, demand response and bypass control to IEC 61511 clause 16
What this element is and why it matters
Phase 6 covers the operational life of the safety instrumented system through proof testing that verifies continued integrity of each function, repair when failures are detected, response to actual demand events and disciplined control of bypasses and overrides. Clause 16 also asks for a documented safety manual that your operating teams reference every day.
Individual significance for organisations
Phase 6 is where the safety instrumented system either earns or loses the integrity it claims. Facilities with disciplined proof testing hold their safety integrity level claims across a 20 year life, while sites without it accumulate undetected failures that only surface during a real demand, and we keep your facility firmly in the first group.
Contribution to Functional Safety Lifecycle Implementation
Phase 6 generates the operational reliability data that feeds back into Phase 4 for re verification when components change and informs the modification triggers of Phase 7. It also produces the Stage 4 functional safety assessment evidence that proves your safety integrity level claims remain valid.
What compliant execution looks like
How we implement this element
A focused six step methodology calibrated to deliver operation and maintenance as a working capability rather than a documented compliance artefact.
We author a procedure for each function covering the sensor stimulus, the logic verification and the final element actuation, and we specify the proof test coverage from the coverage analysis.
We execute at the calculated interval derived from the probability of failure on demand, document the as found and as left condition, and trigger repair if any failure is found.
To clause 16.4 we track mean time to repair, establish the root cause for revealed failures and notify the functional safety engineer of any systematic pattern.
To clause 16.5 we analyse each demand response, verify that the function acted successfully and identify any systematic issue.
To clause 16.2 we set the authorisation hierarchy, the time limits, the compensating measures and the audit log, and we align with management of change for any extended bypass.
Every three to five years to paragraph o of OSHA PSM and IEC 61511 we review the proof test records, the demand responses and the modifications.
Element implementation flow chart
A decision gated workflow that shows the actual sequence of activities from initiation through steady state operation, with key decision points highlighted.
What we produce
- A proof test programme for each function
- A repair and failure tracking database
- A Stage 4 operational assessment pack
- As found and as left proof test records with the coverage basis
- A bypass and override log with compensating measures and time limits
- A reliability data reconciliation comparing the field failure rate against the assumed average probability of failure
Where execution fails
- Proof test coverage claimed higher than what is actually achievable
- Bypasses authorised by operators without any compensating measures
- Demand responses that are never formally analysed
- A proof test interval that is never shortened even when as found failures exceed the assumptions
Codes this element is built on
Explore related elements in this framework
Functional Safety Lifecycle Implementation full element index
Talk to us about implementing Operation and Maintenance
We can scope this element implementation against your facility, regulatory context, and existing management system maturity, then integrate it with the other Functional Safety Lifecycle Implementation elements you already operate.