SILProof is an engineering-support workspace. Its outputs depend on the information and assumptions entered by the user. This page explains the current tool scope and gives a review path; it is not an independent validation of the calculation engine or an interpretation of a project’s compliance.
What the tools cover
| Tool | Current purpose | What it does not establish alone |
|---|---|---|
| Risk Analysis | Record a required SIL or risk-reduction basis using the available risk-analysis workflows. | That the selected method or criteria are approved for a specific project. |
| PFD calculator | Screen a low-demand 1oo1 PFDavg estimate from entered assumptions. | The performance, architecture or systematic capability of a complete SIF. |
| SFF / HFT calculator | Screen maximum architectural SIL capability for a selected route and inputs. | A quantitative PFDavg / PFH result or the achieved SIL of a complete SIF. |
| SIL Verification | Connect quantitative, architectural and systematic-capability information for a SIF. | Certification, independent assessment, validation or approval of the design. |
| SRS Builder | Structure and export a draft Safety Requirements Specification. | Approved or complete project requirements without responsible review. |
See the SIL Verification overview for the whole-SIF path and the calculator overview for screening boundaries.
Equations and model scope
The Formula Library in the Knowledge Hub separates equations identified as represented in SILProof’s current calculation engine from reference equations that may be useful in engineering work but are not necessarily implemented by the calculator. Follow that distinction when comparing a displayed equation with an output.
The PFDavg note describes the low-demand model scope and key inputs. The Route 1H and Route 2H / Table 6 notes describe the architectural routes presented by the site. Check the applicable standard edition and project interpretation before using a route result.
Inputs and evidence to confirm
- Demand mode and target: confirm the hazard-analysis basis, required SIL and the applicable probability metric.
- Failure data: record the source, units, device applicability and assumptions. Prefer project-approved vendor safety manuals or other justified data sources over illustrative values.
- Architecture: confirm subsystem boundaries, voting, device type, HFT and route against actual device evidence and project requirements.
- Proof testing and repair: check interval, coverage, mission time, restoration assumptions and the planned test procedure.
- Common cause and diagnostics: document the basis for beta factor, diagnostic claims and dependencies between channels.
- Systematic capability: retain evidence that supports the capability claim; do not infer it from a quantitative result.
Illustrative example values are for learning the workflow. They are not device recommendations, generic certified failure rates or project data.
A review path for each result
- Confirm the SIF boundary and the risk basis.
- Check every input, unit, source and assumption against project-controlled evidence.
- Review the quantitative result and its model limitations.
- Check the applicable architecture route and systematic-capability evidence separately.
- Compare the result with the SRS, project procedure and applicable standard edition.
- Have the responsible competent reviewer document conclusions, open items and approval outside the calculator.
Primary references
- IEC 61511 series: Functional safety — Safety instrumented systems for the process industry sector. Check the edition adopted for the project.
- UK Health and Safety Executive: Functional safety. Public overview of lifecycle and management responsibilities.
This guide documents intended tool boundaries and user review considerations. It does not state that an external body has independently validated SILProof’s implementation.