Valve buying guides
Guides · Buyer reference
Reference pages for the questions that come before a valve order: verifying an API licence, comparing cryogenic test standards, agreeing an inspection plan and writing an RFQ that can be quoted. No factory is named and no price is quoted here.
All guides
- Guide · API 6D · API 609 · API Composite List
Why “Active” does not prove an API licence is valid
Why “Active” in the API Composite List is not proof on its own: what we found for Wenzhou valve licences, and seven steps to verify an API licence.
Updated 9 Nov 2026
- Guide · BS 6364 · ISO 28921-1 · Cryogenic valves
BS 6364 vs ISO 28921-1: what a cryogenic test proves
How BS 6364 and ISO 28921-1 differ: scope, test temperature, helium leak measurement, and type testing versus production testing.
Updated 10 Nov 2026
- Guide · ITP · FAT · EN 10204 · MDR
Valve inspection before shipment: the procedure to agree
The inspection sequence for an engineered valve order: ITP, EN 10204 3.1 certificates, NDE, API 598 or API 6D tests, FAT witness, packing and the MDR.
Updated 10 Nov 2026
- Guide · RFQ · Specification and testing
Valve RFQ checklist: the data a quotation needs
The 15 fields a valve RFQ needs, from valve type and pressure class to testing, actuation and destination, and why each one changes the quotation.
Updated 10 Nov 2026
- Guide · API 6D · ASME B16.10
API 6D face-to-face dimensions: where they come from
API 6D valves take their face-to-face and end-to-end dimensions from ASME B16.10. How to read the right table, and what to check on the drawing.
Draft: values to be confirmed
What these guides are
The guides describe public standards and the procedure of an engineered valve order. They name no factory, quote no price and claim no test result: where a value depends on the manufacturer or the order, it is marked “To be confirmed” rather than estimated.
For the licence check itself, start with why the registry’s Active flag is not enough.