How should bypasses and overrides be managed in SIS?

Bypass and override management: minimize bypasses by design (avoid need through robust SIF design), provide physical indication (key switches, illuminated status), limit bypass duration (automatic reset timers where possible), maintain bypass log (who, what, when, why), implement compensating measures during bypass (increased operator vigilance, backup protection), restrict bypass authorization (management approval required), and include bypass status in control room displays prominently. IEC 61511 requires bypass consideration in PFDavg calculations if routine. For testing bypasses, use written procedures with verification steps. Distinguish between maintenance bypasses (planned) and operational overrides (emergency response).