{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.safety-integrity-level","code":"thing-q595445","url":"https://ver.cy/models/thing/q595445/","name":"Safety Integrity Level","alternateNames":[],"kind":"thing","status":"published","version":"0.2.0-wave.3","language":"en","classifiers":{"family":"Thing Registry","category":"Cross-cutting context","entryKind":"thing","plane":"XCT","domain":["XCT.QTY"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A discrete level, from 1 to 4, specifying the required reliability of a safety function performed by an electrical, electronic or programmable system, defined in IEC 61508 and sector standards such as IEC 61511 for process industries, with higher levels demanding lower probability of failure on demand and more rigorous development processes; SIL is assigned through risk assessment and verified through design, testing and management measures, and related schemes include automotive ASIL and railway SIL.","purpose":"Let an agent explain Safety Integrity Levels and how they are assigned and achieved, relay the standards and target failure measures, describe sector variants, and distinguish SIL from other safety ratings.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Four levels","Probabilistic targets","Systematic capability requirements","Lifecycle approach"],"structure":{"bundles":[{"id":"understand","name":"Understand","description":"What SIL is.","layers":[{"id":"definition","name":"Definition","description":"Definition and levels.","findings":[{"id":"definition-finding","name":"Definition","description":"Definition.","questions":[{"text":"What is a Safety Integrity Level, and what do the four levels require?","kind":"definition"},{"text":"Is the question about SIL, ASIL, performance level or another rating?","kind":"boundary"}]}]},{"id":"metrics","name":"Metrics","description":"Target failure measures.","findings":[{"id":"metrics-finding","name":"Metrics","description":"Metrics.","questions":[{"text":"What are PFD, PFH, hardware fault tolerance and systematic capability?","kind":"definition"},{"text":"Which entry fits the specific metric?","kind":"action"}]}]}]},{"id":"apply","name":"Apply","description":"Assignment and achievement.","layers":[{"id":"assignment","name":"Assignment","description":"Assigning SIL.","findings":[{"id":"assignment-finding","name":"Assignment","description":"Assignment.","questions":[{"text":"How is SIL assigned through risk graphs, LOPA and other methods, in general terms?","kind":"provenance"},{"text":"Is the user asking about a specific safety system, which needs qualified functional safety engineering?","kind":"boundary"}]}]},{"id":"achievement","name":"Achievement","description":"Achieving SIL.","findings":[{"id":"achievement-finding","name":"Achievement","description":"Achievement.","questions":[{"text":"How are SIL targets achieved and verified through design, testing and lifecycle management?","kind":"provenance"},{"text":"Which references are standard?","kind":"provenance"}]}]}]},{"id":"sectors","name":"Sectors","description":"Sectors and certification.","layers":[{"id":"sectors","name":"Sectors","description":"Sector standards.","findings":[{"id":"sectors-finding","name":"Sectors","description":"Sectors.","questions":[{"text":"How do process, rail, nuclear and machinery sectors apply SIL or analogues?","kind":"provenance"},{"text":"Which entry fits the specific sector standard?","kind":"action"}]}]},{"id":"certification","name":"Certification","description":"Certification.","findings":[{"id":"certification-finding","name":"Certification","description":"Certification.","questions":[{"text":"How are products and systems certified to SIL, and what do certificates mean?","kind":"provenance"},{"text":"Which sources are cited?","kind":"provenance"}]}]}]},{"id":"context","name":"Context","description":"History and debate.","layers":[{"id":"history","name":"History","description":"History.","findings":[{"id":"history-finding","name":"History","description":"History.","questions":[{"text":"How did SIL develop from early safety standards to IEC 61508?","kind":"provenance"},{"text":"Which entry fits functional safety?","kind":"action"}]}]},{"id":"debate","name":"Debate","description":"Critiques.","findings":[{"id":"debate-finding","name":"Debate","description":"Debate.","questions":[{"text":"What critiques of SIL and probabilistic safety targets exist, with positions attributed?","kind":"provenance"},{"text":"Is the presentation neutral?","kind":"boundary"}]}]}]}]},"agentConduct":{"may":["Explain Safety Integrity Levels and what they require, citing the standard used.","Check documentation that a safety function's claimed level is supported by an assessment."],"mustNot":["Claim or assign a SIL to a safety function without a proper assessment.","Weaken, bypass or disable a safety function in operation.","Change software or hardware in a safety function without managed change control.","Mix the levels of different standards, such as SIL and ASIL, as if equal."],"requiresHuman":["Approving a safety function's SIL or any change to it.","Returning a plant to operation with a safety function bypassed."]},"ethics":{"considerations":["Safety functions protect workers and the public from fires, explosions and toxic releases.","Overstated integrity gives false confidence where lives depend on it."],"affectedParties":["Plant workers","Nearby communities","Operators and engineers"]},"owners":{"steward":"The owner and operator of the safety system, under its functional safety management.","roles":[],"masterSystems":[]},"relations":[{"target":"Q7336288","type":"parent","note":"registry parent class"},{"target":"risk metric","type":"related","note":"in registry terms"},{"target":"IEC 61508","type":"related","note":"the base standard"},{"target":"safety instrumented system","type":"related","note":"in process plants"},{"target":"ASIL","type":"related","note":"the automotive scheme"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.safety-integrity-level","Wikidata: Q595445 (https://www.wikidata.org/wiki/Q595445)","IEC 61508: functional safety standard","IEC 61511: process industry standard"]},"properties":{"applicability":"not-applicable","items":["SIL 1 PFD range: 0.1 to 0.01 probability - low demand","SIL 4 PFD range: 0.0001 to 0.00001 probability - low demand"]},"recognition":{"applicability":"optional","items":["Reliability level of a safety function","SIL 1 to 4 under IEC 61508 and IEC 61511","ASIL applies to automotive; performance levels apply under ISO 13849; a SIL rating is not a product safety mark alone","Not a visible object; a rating in safety documentation and product certificates."]},"capabilities":{"applicability":"required","items":["explain the levels and metrics","relay standards and assignment","describe sector variants","distinguish from other ratings"]},"hazards":{"applicability":"required","items":["Misusing SIL as a product label without context","Incorrect risk assessment","Confusing SIL with other ratings","Agents giving safety-critical engineering advice"]},"interfaces":{"applicability":"required","items":["IEC 61508 and sector standards","Certification schemes by bodies such as TUV and exida","Regulatory expectations in process, rail and nuclear sectors"]},"context":{"applicability":"required","items":["Specifying required safety system reliability.","SIL under IEC 61508","SIL in process industries under IEC 61511","railway SIL under EN 50126 series","automotive ASIL under ISO 26262 as an analogue","machinery performance levels under ISO 13849 as an analogue"]}},"sources":[{"title":"Wikidata item Q595445: Safety Integrity Level","url":"https://www.wikidata.org/wiki/Q595445","note":"identity and sense of the item"},{"title":"Wikipedia: Safety integrity level","url":"https://en.wikipedia.org/wiki/Safety_integrity_level","note":"general description of the item"}],"openQuestions":["Should safety instrumented system be the primary linked entry?","How should standards be linked?","How should sector variants be recorded?"],"resources":{"spec":"/models/things/publications/thing-q595445/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q595445/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-13T01:57:22Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"not-applicable","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-06T19:52:01+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass","interaction.properties":"Plane XCT: no invented physical properties."},"score":1.0}}