A human-made classification system that quantifies the reliability of safety-related control systems, assigning discrete integrity levels (SIL 1 through SIL 4) based on probabilistic failure criteria. Each level specifies a range of probability of dangerous failure per hour (PFH) for random hardware faults, with SIL 4 being the most stringent. The system is defined by IEC 61508 and sector-specific standards (e.g. IEC 61511 for process industry), persisting through international standardization bodies, regulatory mandates, and industry certification regimes. A SIL assignment dictates the required architecture, diagnostics, and verification rigor of the safety instrumented function it governs — higher SIL demands redundant channels, diverse implementations, and more thorough validation.\n\n[formal: safety_integralis_gradus | substrate: mind | horizon: generations | explicit: yes | epoch: 0.01]
Accepted ontology entry
safety-integrity-level
A human-made classification system that quantifies the reliability of safety-related control systems, assigning discrete integrity levels (SIL 1 through SIL 4) based on probabilistic failure criteria. Each level specifies a range of probab…
Definition
Why it is in scope
A human-made classification system that quantifies the reliability of safety-related control systems, assigning discrete integrity levels (SIL 1-4) based on probabilistic failure criteria. Built by IEC 61508/61511 standards to provide measurable targets for safety system design and verification.
Names and aliases
- safety-integrity-levelen · CANONICAL
Relations from this entry
- cms8plcb701p373fkx9us3cymSERVES →
safety-integrity-level is a classification system created and maintained for the sake of functional-safety. SIL levels (1-4) are the core quantitative mechanism by which functional-safety standards (IEC 61508/61511) specify, design, and verify safety requirements. Law 8d: for whose sake? SIL exists to make functional-safety engineering possible — it is the metric that functional-safety works around.
- cms8n88bw01gh73fkl86xl2mnSERVES →
Safety integrity levels are classification metrics built for the sake of safety-assessment: they quantify the reliability requirements of safety functions, providing the numerical basis for assessing risk reduction needs.
Relations to this entry
No accepted relations in this direction.
Record identity
- Created
- Jul 31, 2026, 9:13 AM UTC
- Content hash
- af084b2fdea7eeca364b9270666c176eb21d7275fc9916a8bde17aaa206cca7f