How do you manage SIS component obsolescence while maintaining SIL compliance?

SIS obsolescence management: establish component monitoring program (manufacturer notifications, industry alerts), maintain lifecycle data for all SIS components, plan replacements before end-of-support, evaluate replacement options (like-for-like, upgrade to better technology, system replacement), assess functional equivalence (safety manual data, response time, diagnostics), verify replacement meets original design requirements (recalculate PFDavg if needed), implement as formal modification (MOC process), update all documentation (SRS, drawings, procedures), and retrain personnel. Challenges: newer devices may have different failure characteristics, testing interfaces may change. Consider technology refresh projects during planned turnarounds. Document obsolescence risk in asset management system.