Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · Verification and validation

SIL verification

Also known as: SIL calculation, SIL verification calculation

German: SIL-Verifikation

In functional safety, SIL verification is the demonstration that a designed safety function meets its required safety integrity level, covering the failure measure (PFDavg or PFH), the architectural constraints such as hardware fault tolerance, and the systematic capability of its elements.

  • Verification
  • Functional safety

In one sentence

SIL verification demonstrates that a designed safety function meets its required SIL in failure measure, architecture and systematic capability.

Example

The SIL verification for a SIL 2 trip combines failure rates of the transmitter, logic solver and valve with a 12-month proof-test interval and confirms that PFDavg is within the SIL 2 range.

How it applies

  • Calculation: The failure measure is computed from component failure rates, diagnostic coverage, common-cause factors, proof-test interval and coverage, and mean repair time. Tools support this, but the input data remain the engineer's responsibility.
  • Architecture and systematic capability: A good number alone is not enough. The Hardware fault tolerance (HFT) and the systematic capability of each element must also fit the required SIL.
  • Change: Any change to devices, voting, test intervals or operating mode requires repeating the verification.
  • Documentation: Keep the calculation with its sources of failure data and the conditions from each device's safety manual. The documentation team should carry these conditions, such as test intervals and replacement periods, into maintenance documentation.

SIL verification vs. SIL validation

Verification is done on the design and on the results of each phase. SIL validation tests the installed system against the safety requirements specification. Both are required; neither replaces the other.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: AI TechDoc Knowledge editorial definition, based on IEC 61508:2010 and IEC 61511-1:2016

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

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