What are the phases of the Safety Lifecycle per IEC 61511?

IEC 61511 Safety Lifecycle phases: Analysis phase - hazard and risk assessment, SIL allocation, safety requirements specification (SRS); Realization phase - SIS design, application programming, integration, SIS verification; Operation phase - installation, commissioning, validation, operation and maintenance, modifications, decommissioning. Each phase has defined activities, verification requirements, and documentation. The lifecycle is iterative - changes require re-assessment. Key documents: SRS (what SIS must do), safety manual (manufacturer data), proof test procedures, and validation report. Competent personnel required at each phase.