Every industrial valve order should arrive with material certificates — but “a cert” is not one thing. EN 10204 defines the types, and the difference between 3.1 and 3.2 decides who validated your material and what it costs.
The EN 10204 Certificate Types
- Type 2.1 — declaration of compliance, no test results. Commodity fasteners territory.
- Type 2.2 — test report with non-specific results (not from your actual batch).
- Type 3.1 — the industrial standard: chemical and mechanical results for YOUR heat/batch, validated by the manufacturer’s own independent QA department.
- Type 3.2 — same specific results, but countersigned by a party independent of the manufacturer: the purchaser’s representative or a third-party inspector (Lloyd’s, BV, TUV…).
When 3.1 Is Enough
Nearly all standard industrial valve orders: API 600/602/607 valves, strainers, stainless valves — body, bonnet, trim and bolting to 3.1 is the default we quote and deliver.
When Projects Demand 3.2
- Critical service on owner/EPC specs (sour gas, high pressure, offshore).
- Nuclear-adjacent and marine-class work where the class society countersigns.
- When traceability disputes carry heavy commercial risk.
Expect 3.2 to add cost and 2–4 weeks (inspector scheduling). Specify it per line item, not blanket — certifying gaskets to 3.2 helps no one.
Reading a 3.1 Certificate in 60 Seconds
Match: heat number on cert = heat number stamped on the valve body; grade (e.g. A216 WCB, A182 F316L) = datasheet; check mechanicals against the standard’s minimums; confirm any overlays (NACE hardness, impact tests at −46 °C for LCC, cryogenic impacts for cryogenic valves).
The Four Certificate Types at a Glance
| Type | What it states | Who validates it |
|---|---|---|
| 2.1 Declaration of compliance | The goods meet the order. No test results at all. | Manufacturer |
| 2.2 Test report | Results from non-specific inspection — production data, not from your batch | Manufacturer |
| 3.1 Inspection certificate | Results of specific inspection on the material actually supplied | Manufacturer’s authorised inspection representative, independent of the manufacturing department |
| 3.2 Inspection certificate | Same specific inspection, countersigned | Manufacturer’s representative and the purchaser’s inspector or a body designated by regulation |
The distinction that matters commercially is between 2.2 and 3.1: a 2.2 report describes material of the same specification, not the material in your crate. If the specification calls for traceability, 2.2 does not satisfy it no matter how detailed the numbers look.
What a Valid 3.1 Certificate Must Actually Contain
A certificate is only useful if it ties a document to a physical object. Check for all of the following before accepting it into a submittal package:
- Heat or cast number, and that same number physically marked or tagged on the component. This is the link that makes the whole document meaningful.
- Chemical composition of the heat, with the specification limits shown alongside the actual values.
- Mechanical properties — tensile strength, yield, elongation, and impact values where the material specification or design temperature requires them.
- Heat treatment condition (normalised, quenched and tempered, solution annealed) — relevant because it governs the properties claimed.
- Non-destructive examination results where the order specified them, identified by method.
- Reference to the governing standard and grade, and to your purchase order.
- Signature of an inspection representative independent of production. A 3.1 signed by the production manager is not a 3.1.
What Triggers a 3.2 Requirement — and What It Costs You
A 3.2 is not a “better” 3.1 — it is a 3.1 with an independent witness. The requirement normally arrives from one of four directions: a client or EPC specification that names it outright; pressure equipment falling in the higher PED categories where a notified body is involved; offshore, nuclear or marine classification work; or an insurer or authority requiring third-party surveillance on a particular scope.
The practical consequence is schedule, not paperwork. A 3.2 means an inspector from a third-party body — or your own representative — must be physically present at the mill or test bench when the tests are performed. That has to be booked against the production schedule. Discovering a 3.2 requirement after material has been produced usually means re-testing or re-manufacture, because a witness cannot retroactively witness anything.
Ask at RFQ stage, not at submittal stage. If the specification is ambiguous, resolve it in writing before the order is placed. The cost difference is modest; the schedule difference is not.
Red Flags When Reviewing Certificates
- No heat number, or a heat number that does not match the marking on the part.
- A certificate that references a standard the material does not actually claim, or an obsolete edition.
- Identical certificates for parts that came from different production runs.
- A “3.1” with no independent signatory, or a signature block from the production department.
- A scanned certificate with edited fields — different fonts or alignment in the values row is the usual tell.
- Certificates supplied only after repeated requests. Documentation that is hard to obtain before delivery is usually harder to obtain after.
Frequently Asked Questions
Is a mill test report (MTR) the same as 3.1?
In practice yes — North American “MTR” usually corresponds to EN 10204 3.1 content. The EN designation makes the validation level explicit.
Can a distributor issue 3.1 certs?
The certificate originates from the material manufacturer; a distributor passes it through with traceability intact. That chain of custody is exactly what we maintain on every ValveAtlas order.
What about counterfeit certificates?
Cross-check heat numbers with body stamps and, for critical orders, request PMI (positive material identification) testing — cheap insurance against the industry’s known counterfeit problem.
Want a documentation checklist for your next order? Ask us — we will template it for your project.
