About & Methodology

What this tool does, where the numbers come from, and — more usefully — what it refuses to do.

1. What it is

IndustrialValveSelect is a deterministic pre-selection rule engine for industrial process valves: ball, gate, globe, check and butterfly valves — the five types that cover roughly 85–90% of the global industrial valve market. You tell it what the valve has to do (isolate, throttle, or prevent backflow), plus medium, pressure, temperature and size; it returns a valve type, body and seat materials, a pressure class per ASME B16.34, and an RFQ-ready specification sheet.

It exists because the first days of a valve enquiry are usually spent asking a manufacturer to explain things a catalogue could have said. The answer you get here is deliberately a starting frame for a quotation request, not a substitute for a manufacturer's engineering judgement.

2. Why there is no AI answering you

The recommendation you receive is produced by the same code every time, from a knowledge base you can read. Three reasons:

Reproducibility. Two engineers entering the same duty get the same answer, today and next year — and we can show you exactly which constraint produced it.
Auditability. Every recommendation carries an "elimination record": every valve type it considered and, for the ones it rejected, the specific reason. You can check our reasoning against your own experience instead of taking it on trust.
Responsibility. A plausible-sounding wrong valve specification is a safety and budget problem — a gate valve sold for throttling, a resilient seat sold for steam. We prefer an honest "this needs an engineer" to a confident guess.

3. Where the data comes from

Three traceable sources, all public:

Media compatibility for 40 process media, shared with our sister tool for chemical pumps and re-expressed for valve body castings (carbon steel → A216 WCB, 316 stainless → A351 CF8M, and so on), with conservative tie-breaking and caveats carried verbatim.
Pressure-temperature ratings from ASME B16.34, Groups 1.1 (WCB) and 2.2 (CF8M), as reproduced in manufacturer catalogs. For body alloys outside those two groups we print no computed class — the report says to assign it per B16.34 for the selected group instead of inventing a number.
Valve-type envelopes calibrated from manufacturer selection literature (floating-versus-trunnion ball construction, butterfly offset designs, wedge-versus-parallel-slide gates on steam, check-valve functional limits), cross-checked against the Chinese supplier pool that our enquiries are actually routed to.

Three independent temperature gates, all checked. A recommendation must pass the body's material ceiling (e.g. WCB 425 °C), the medium's compatibility ceiling (e.g. carbon steel in concentrated sulfuric acid holds only to 40 °C), and the seat's ceiling (EPDM 120 / PTFE 200 / metal 600 °C). A heat-proof body with a melting seat is a scrapped valve — and so is a compatible body pushed past its rating table.

4. What the engine actually checks

Function first. A ball valve held half-open erodes its seats; a gate valve used for throttling wire-draws itself. These are hard violations here, not warnings — the two most expensive mistakes in valve selection.
Pressure class from ASME B16.34: the lightest class whose published rating covers your pressure at your temperature, not a pressure-to-class rule of thumb.
Construction boundaries with their reasons printed: floating versus trunnion ball (from DN150, or Class 600+), butterfly offset design by class and temperature, wedge-gate seizure risk on steam above 250 °C, bolted versus pressure-seal bonnets above Class 600.
Service flags that change the answer, not just the prose: sour (NACE MR0175) service, oxygen-clean duty, fire-safe requirements, cryogenic bonnets, abrasive media.

5. Boundaries we do not cross

The following get no automatic recommendation. To be exact about who does what: we read the enquiry, confirm we received it within 24 hours and forward it to valve manufacturers. The sizing, material confirmation and quotation belong to the manufacturer's engineering team — we have no engineers on staff, and we do not promise another company's response time.

Safety/relief valves — sizing them is a pressure-system calculation (API 520/521) where an error is a safety incident.
Modulating control valves — Cv calculation, flow characteristic and actuator selection are a different discipline we stay out of.
Working pressure above 420 bar, temperature above 538 °C or below -46 °C (cryogenic selection details — cold-box layout, drip plates, BS 6364 scope — sit outside our data), and sizes above DN1200 (project-engineered valves).
Heavy slurry duty with a bubble-tight requirement — the classic answer (knife-gate valves) is outside our launch catalogue.
Hydrofluoric acid and oleum — high-hazard media that no template answer should touch.
Concentrations outside the rated band of a medium, or stated in °Bé (no safe automatic conversion without a media-specific gravity table).
Any duty where no valve type in our catalogue survives — you get the full elimination list instead of something bent into shape.

6. Business model, stated plainly

This tool is free because it is supported by Chinese manufacturing partners. If you ask us to, we forward your inquiry to valve manufacturers so they can quote. We do not rank suppliers for money, we do not take commission on a sale, and we do not claim to have audited anyone. Supplier verification is listed as a checklist precisely because it is your job, not ours.

See the Privacy Policy for what happens to your contact details.

7. Known limitations

Ratings are screening values from published tables: piping loads, thermal cycling, fugitive-emission class and actuation sizing are all for the manufacturer to confirm.
Seat temperature ceilings are vendor-consensus values (NBR 80 / EPDM 120 / PTFE 200 / RPTFE 230 / metal 600 °C); compound recipes vary ±10–20 °C between manufacturers — confirm the datasheet.
Key construction boundaries carry documented source disagreements (steam wedge gates, floating-ball limits, double-offset metal-seat ceilings). We print both positions and how we resolved them rather than quietly picking a winner.
Check valves are screened at the functional level only — slam behaviour on critical pump discharge needs a transient (water-hammer) study this tool does not perform.
No manufacturer model numbers, and no price bands at all: the cost of the same valve swerves on body material, seat, certification scope (NACE, fire-safe, cryogenic) and actuation far more than any honest band would capture — so the report stops where a quotation starts.

Knowledge base v0.1.0 · Last updated September 2026.