First Out Functional Safety & Industrial AI

First Out AI · functional safety calculator

The SIL calculator that shows you where you went wrong.

Named after the first-out alarm: it tells you what to look at first.

Verify safety instrumented functions in the browser: PFDavg or PFH, fault tolerance and systematic capability against the target SIL, with an engineer's reading of every result. On paid plans, ask the AI where the mistake is, which input looks wrong and what the cheapest fix would be.

Open First Out AI free Test yourself: six questions Plans and prices
  • Free to startNo sign-up: 1oo1, 1oo2 and 2oo3 with the engineer's reading and what-if on every result
  • Ask the AI300 questions a month on Pro about your own functions, grounded in your inputs and the engine result
  • Tested engineEvery formula checked against an independent second implementation; methods published
  • Built by an FSETÜV Rheinland Functional Safety Engineer with 12+ years in process plant instrumentation and control

The idea in ten seconds

Move the proof test interval and the failure rate and watch the probability of failure on demand and its SIL band change. This is the simplified picture; the full tool does the real calculation per element and per group.

Quick checkSimplified PFDavg for one subsystem
Voting
12 months
0.50 per million hours
PFDavg–
Risk reduction factor–
SIL band, by PFD aloneSIL 2

PFD over six years: it rises between proof tests and resets at each test. The dashed line is the average. Hover, or focus the chart and use the arrow keys, for values.

Simplified equations for one element per subsystem, with no diagnostics, no repair time and 100 % test coverage. The full tool computes time-dependent PFD per group with proof test coverage, mission time and common cause, then checks fault tolerance and systematic capability. See the methods.

New on every paid plan

Ask the calculation why.

A calculator gives you a number. First Out AI also explains it: which subsystem drives the result, which input is out of range, what to change and what that change does. The engine computes; the AI never changes the numbers.

You askSIF-01, target SIL 2

Where is my mistake?

First Out AI answersfrom your inputs and the engine result

Transmitters: λDU is entered as 1 × 10⁻⁴ per hour, about 0.9 dangerous undetected failures per transmitter per year. Certified transmitters are typically 100 to 1,000 times lower: check the unit and the certificate.

The two transmitters are voted 1oo2 with a common cause factor of 0 %. Redundant channels are never fully independent; enter the β you can justify.

Try the same function with the certificate value and β 5 %, then compare the result.

Illustrative answer. Answers come from Claude (Anthropic) and must be checked by a competent functional safety engineer.
  • 300 questions a monthon Pro and Project Pass, 1,500 on Team; top-up of 500 for $9
  • Grounded in your functionevery answer uses your inputs and the engine result, not a generic chat
  • Your datasent only when you ask; under Anthropic's commercial terms it is not used to train models
  • Never stops your workif the AI is unavailable or your allowance is used, every calculation still runs

Start free. Upgrade when the AI pays for itself.

Every plan runs the same engine. Prices in US dollars; online payment through Paddle or a purchase order.

  • Freeno sign-up1oo1, 1oo2 and 2oo3 checks, engineer's reading and what-if, PDF report
  • $59per month, or $590 a yearPro: full verification, LOPA, SRS and proof test drafts, 300 First Out AI questions a month
  • $2,490per yearTeam: five users, HAZOP and cause & effect, 1,500 AI questions a month

Compare all plans

What it does

The modules most functional safety engineers rebuild in a spreadsheet for every project. Open a module for the details.

  • SIL verification

    The core module, on every plan: PFDavg or PFH, fault tolerance and systematic capability, one verdict.

    Everything included
    • PFDavg for any voting up to four channels; PFH for 1oo1, 1oo2, 2oo2, 1oo3 and 2oo3
    • Proof test interval, coverage and mission time
    • Common cause (β), repair time, partial stroke tests
    • Hardware fault tolerance: Route 1H, Route 2H, IEC 61511
    • Systematic capability per element
    • Spurious trip rate

  • SIL determination

    Target SIL with a method you can show, using your company's own risk criteria.

    Everything included
    • Layer of protection analysis
    • Calibrated risk matrix with your company's criteria
    • Risk graph
    • Independent protection layers with independence notes

  • Documents

    Drafts generated from the same data, exported to Excel and PDF.

    Everything included
    • Safety requirements specification draft
    • Proof test procedure draft
    • HAZOP worksheet with Excel export
    • Cause & effect matrix with Excel export
    • Printable PDF report and Excel workbook

From drawing to verdict

A function is modelled as subsystems in series; the result shows all three SIL checks together.

Typical safety instrumented function Three pressure transmitters on a vessel feed a logic solver that votes two out of three. A trend shows the pressure rising to the high-high limit; the logic solver then closes the feed valve and flow stops. V-01 to flare PSV PT 01A PT 01B PT 01C Logic solver votes 2oo3 XV-01 Feed To process Closed on trip PT-01 trend bar g HH Safe state reached
SIF-01: high pressure protection on V-01Three pressure transmitters voted 2oo3 close the feed valve before the vessel overpressures. StatusIllustrative drawing, not a client design Sheet 1 of 1
SIF-01: high pressure on V-01Target SIL 2
CheckBasisResult
PFDavg ≤ required (from LOPA)Sensors, logic solver and final element in seriesPass
Hardware fault toleranceIEC 61511 minimum HFT for the target SILPass
Systematic capabilityEvery element rated for the target SILPass
Proof test coverageCoverage and mission time applied per elementReported
Spurious trip rateFrom safe and detected failure ratesReported
Interface preview with illustrative values. First Out AI supports engineering judgement and does not replace it; it is not certified software.
1Every number can be traced

Each result shows the method used, the intermediate terms and the source of each failure rate. A reviewer can follow the calculation without opening a separate file. Read the calculation methods.

2Your data, not a bundled database

Failure rates come from the device certificate, the FMEDA report or your own data, entered with their source. First Out AI includes no third-party reliability database, so you are never relying on a number you cannot show.

3No installation

It runs in the browser; calculations run on the server, and project data can be exported or deleted at any time. An on-premises version for plants with restricted internet access is planned.

4Engineering judgement still required

First Out AI supports engineering work and does not replace it. Results must be checked by a competent functional safety engineer before they are used. First Out AI is not certified software. Licence and disclaimer.

Test yourself: six questions on SIL, LOPA and proof testing

The points that decide whether a SIL verification holds up in review. Two minutes, no sign-up, with the reasoning behind each answer.

At the end you get a score and a suggested next step: check your existing calculations in First Out AI, or start a new function on the free plan.

  1. Pick an answer, then check it. The explanation shows the method behind the right answer.
  2. Questions cover the three SIL checks, proof test interval and coverage, common cause, fault tolerance and LOPA independence.
  3. Your answers stay in your browser; nothing is sent anywhere.
Functional safety checkQuestion 1 of 6
Questions and answers are illustrative training material written for this site; they do not reproduce any standard or course.

Worked examples, computed with First Out AI

Illustrative designs and data, chosen to show the method; every input, result and chart is on the page.

All case studies

Other services

Need an engineer, not only a calculator?

The same engineer behind First Out AI takes fixed-scope work, delivered remotely: functional safety studies, control and safety system reviews, commissioning documents and industrial AI for process plants.

All services, packages and prices

Questions

Can I try it before buying?

Yes. The free plan runs the SIL verification for 1oo1, 1oo2 and 2oo3 voting with a perfect proof test, and prints a watermarked report. Open First Out AI.

Which standards does it follow?

IEC 61511 for the process sector and IEC 61508 for device-level requirements. PFDavg is the time-domain average of PFD(t) with your proof test coverage and mission time; the simplified equations of IEC 61508-6 are shown beside it as a cross-check. Methods and tests.

Can my company buy it with a purchase order?

Yes. Project Pass, Team and Enterprise can be bought by quote, purchase order and invoice. See plans and procurement.

Where is project data stored?

In your browser by default. With a paid plan you can also save projects to a database hosted on Cloudflare, isolated per licence and encrypted in transit; you can download or delete them at any time. An on-premises version is planned for Enterprise customers.

Model your first safety function in the browser. No installation, no account needed for the free plan.

Open with the exampleUser guideSee plans

Built by Ali Telek

A functional safety engineer who got tired of spreadsheets that hide mistakes.

First Out is run by Ali Telek, TÜV Rheinland certified Functional Safety Engineer. Questions about the tool, a purchase order or a study you need done: write directly. About Ali Telek.

contact@firstout.ai Start a conversation

Engagements are screened for conflicts of interest before acceptance.