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Built for engineers who own the judgement call. SILVerify handles the calculation and the documentation. The engineering responsibility stays with you.
The problem is not your calculations. The problem is the workflow. Spreadsheets were never designed to produce auditable, client-ready verification documentation. They are calculation tools pressed into service as documentation tools — and the gap between what they do and what a professional verification requires is where the risk lives. And the traditional alternative — an enterprise SIL software licence — means a procurement process, a purchase order, and paying for a tool three times a year whether you use it or not.
My default has always been a spreadsheet. It works, but the gap between a finished calculation and a finished report is where the time goes — and where the risk lives if someone else has to pick it up later. I used SILVerify on a live project and the report it produced was better structured than what I’d have written myself. Everything is traceable from input to conclusion. For anyone doing this work independently, it’s hard to justify the spreadsheet route once you’ve seen the alternative.
SILVerify assesses all three barriers and determines achieved SIL as the minimum of the three results. The limiting barrier is flagged automatically.
Traditional SIL verification software is sold as an annual seat licence — a significant procurement decision that takes weeks to approve and commits you to a fixed cost regardless of how many projects you actually run. For large consultancies with continuous project flow that model makes sense. For independent consultants and smaller engineering firms it does not.
SILVerify is structured around how independent engineers actually work. Your verification history and project archive are always there when you need them. Active month? Pay for what you use. Quiet month? Just the platform fee.
No procurement process. No purchase order. Pay only for what you need, when you need it.
The results screen shows per-channel PFDavg, subsystem totals, relative contribution, the three-barrier summary, and achieved SIL — with the limiting subsystem flagged automatically.
| Subsystem | Architecture | PFDavg (channel) | Subsystem PFDavg | Contribution |
|---|---|---|---|---|
| Sensors (PT-001A/B) | 1oo2 | 3.68 × 10-4 | 1.77 × 10-4 | |
| Logic Solver (LS-001) | 1oo1 | 6.17 × 10-4 | 6.17 × 10-4 | |
| Final Elements (XV-001) | 1oo1 | 4.38 × 10-3 | 4.38 × 10-3 | |
| Total SIF PFDavg | — | — | 5.17 × 10-3 | SIL 2 ✓ |
⚠ Final Elements at 85% of total PFDavg highlighted as limiting subsystem. Design changes should target final element architecture before any other subsystem.
PFDavg calculated using the IEC 61508-6 low demand model including the residual failure term. All intermediate values are shown in the calculation results screen and carried through to the report.
HFT is derived automatically from the declared architecture. The 2oo2 case — where HFT = 0 regardless of channel count — is assessed correctly and the architectural constraint consequence is stated explicitly in the report.
Baseline single-channel architecture. One failure causes safety function loss. Standard for logic solvers and single-channel final elements where the reliability target is met without redundancy.
Two channels, either activates the function. One failure tolerated — HFT = 1. Improves both PFDavg and the architectural constraint position. Common cause failure (beta factor) required. Most widely used architecture for sensors in SIL 2 applications.
Both channels must function. Neither can fail — HFT = 0, identical to 1oo1. Reduces spurious trip rate but does not improve the safety architectural position. Selecting 2oo2 to improve a SIL claim via Route 1H is a common and costly design error.
Three channels, 2-of-3 voting. One failure tolerated — HFT = 1. Higher PFDavg than 1oo2 for identical channel failure rates. Selected where both availability and safety are critical and the cost of a third channel is justified. Beta factor required.
Every calculation generates a professional Word document read from a frozen input snapshot. The report represents the exact calculation run — not live data. All previous reports are stored permanently and never overwritten.
SILVerify accelerates the work of a qualified functional safety engineer. It does not replace engineering judgement. Scope boundaries are explicit in every report it generates.
Delivering SIL verification on client projects across multiple sites and standards. SILVerify turns 2–4 days of calculation and writeup into a single session. The report goes to the client — complete, documented, signed by you.
Managing a SIS portfolio on an operating facility. SILVerify provides a documented history of every calculation — essential when a modification is proposed, when regulatory inspection is imminent, or when a previous calculation needs to be defended.
Multiple engineers across multiple projects requiring consistent methodology and report format. Team licensing provides a shared tool and shared output format — ending the problem of reconciling three different engineers’ spreadsheet approaches on the same project.
“I built SILVerify because I was sick of the workflow. The calculation was the easy part. Then came checking it again. Then the Word document. Then reformatting every table because a SIF changed. On a project with ten SIFs that process consumed days. SILVerify exists because that time belongs on the engineering, not the paperwork. The defensibility is the point — but getting your time back is a very close second.”
Enterprise SIL software is priced per seat — typically £3,000 or more per year, regardless of how many verifications you actually run. For an independent consultant doing six projects a year that is £500 per project before you have done any work. SILVerify costs £69 per report.
SILVerify is priced around the way independent engineers actually work. The platform keeps your history, your projects, and your device library in place. You pay for reports when you deliver them. That is the entire model — no procurement process, no annual commitment, no cost in quiet months beyond the platform fee.
Full IEC 61508 verification, device library, and report preview. No card. No time limit. See exactly what your clients would receive.