Safety Integrity Level
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.
Bundle → Layer → Finding → Questions Filled
4 bundles · 8 layers · 8 findings · 16 questions
Understand What SIL is.
Definition
Definition and levels.
Definition
Definition.
- What is a Safety Integrity Level, and what do the four levels require? definition
- Is the question about SIL, ASIL, performance level or another rating? boundary
Metrics
Target failure measures.
Metrics
Metrics.
- What are PFD, PFH, hardware fault tolerance and systematic capability? definition
- Which entry fits the specific metric? action
Apply Assignment and achievement.
Assignment
Assigning SIL.
Assignment
Assignment.
- How is SIL assigned through risk graphs, LOPA and other methods, in general terms? provenance
- Is the user asking about a specific safety system, which needs qualified functional safety engineering? boundary
Achievement
Achieving SIL.
Achievement
Achievement.
- How are SIL targets achieved and verified through design, testing and lifecycle management? provenance
- Which references are standard? provenance
Sectors Sectors and certification.
Sectors
Sector standards.
Sectors
Sectors.
- How do process, rail, nuclear and machinery sectors apply SIL or analogues? provenance
- Which entry fits the specific sector standard? action
Certification
Certification.
Certification
Certification.
- How are products and systems certified to SIL, and what do certificates mean? provenance
- Which sources are cited? provenance
Context History and debate.
History
History.
History
History.
- How did SIL develop from early safety standards to IEC 61508? provenance
- Which entry fits functional safety? action
Debate
Critiques.
Debate
Debate.
- What critiques of SIL and probabilistic safety targets exist, with positions attributed? provenance
- Is the presentation neutral? boundary
Classifiers Filled
- Family
- Thing Registry
- Category
- Cross-cutting context
- Entry kind
- thing
- Plane
- XCT
- Domain
- XCT.QTY
What it is Filled
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.
Why it exists Filled
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.
Distinguishing features Filled
- Four levels
- Probabilistic targets
- Systematic capability requirements
- Lifecycle approach
What robots and AI may and may not do Filled
Must not
- 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.
Only with a human decision
- Approving a safety function's SIL or any change to it.
- Returning a plant to operation with a safety function bypassed.
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.
Moral aspects Filled
- Safety functions protect workers and the public from fires, explosions and toxic releases.
- Overstated integrity gives false confidence where lives depend on it.
Who is affected
- Plant workers
- Nearby communities
- Operators and engineers
Owners Filled
Steward
The owner and operator of the safety system, under its functional safety management.
Links to other meta-models Filled
parent
- Q7336288 - registry parent class
related
- risk metric - in registry terms
- IEC 61508 - the base standard
- safety instrumented system - in process plants
- ASIL - the automotive scheme
What else AI and robots need to interact with it Filled
Identity and identifiers required Filled
- 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
Direct properties not applicable Not applicable
- SIL 1 PFD range: 0.1 to 0.01 probability - low demand
- SIL 4 PFD range: 0.0001 to 0.00001 probability - low demand
Plane XCT: no invented physical properties.
Recognition optional Filled
- 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 and actions required Filled
- explain the levels and metrics
- relay standards and assignment
- describe sector variants
- distinguish from other ratings
Hazards and failure modes required Filled
- Misusing SIL as a product label without context
- Incorrect risk assessment
- Confusing SIL with other ratings
- Agents giving safety-critical engineering advice
Standards and interfaces required Filled
- IEC 61508 and sector standards
- Certification schemes by bodies such as TUV and exida
- Regulatory expectations in process, rail and nuclear sectors
Context of use required Filled
- 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 Filled
- Wikidata item Q595445: Safety Integrity Level - identity and sense of the item
- Wikipedia: Safety integrity level - general description of the item
Open questions
- Should safety instrumented system be the primary linked entry?
- How should standards be linked?
- How should sector variants be recorded?
Machine files
Provenance
thing registry research (pass 2) · unreviewed
Built from: models/things/publications/thing-q595445/spec.json