EN 10204 3.1 vs 3.2 certificates: what procurement actually needs
EN 10204 defines material document types, and the practical choice is between type 3.1 and type 3.2. A 3.1 certificate is issued by the manufacturer's own inspection department, independent of production; a 3.2 certificate adds validation by an external or purchaser-appointed inspector. Most valve orders accept 3.1; sour, offshore and critical services often demand 3.2. Decide on the purchase order — certificates are hard to create retrospectively.
What EN 10204 actually is
EN 10204 is the European standard that defines the inspection documents metallic material can be sold against. It does not say how good the material must be — the material specification does that. It defines who verified the material, what results they report, and how independent their signature is. Four document types exist: 2.1 and 2.2 are a manufacturer's declaration and a general test report; 3.1 and 3.2 are inspection certificates carrying real results for the specific material supplied. For valve buying, the working choice sits between the last two.
One point settles most confusion downstream: the certificate belongs to the material, not the valve. It is raised by the mill or foundry when the steel is made and follows the heat number; the valve maker collects it and ties it to the finished valve through markings and serial numbers. Where the certificate sits alongside the test report and the nameplate is mapped in the valve procurement documentation guide. Everything below is published reference data — the governing edition is your purchase order's.
Type 3.1 in plain terms
A 3.1 inspection certificate says: this specific material was tested, these are the results, and the person signing works for the manufacturer but not for the production department. The independence is internal — an inspection representative whose sign-off is deliberately separated from the people who made the melt and want it shipped. The results are specific: chemical composition and mechanical values for the heat actually supplied, not typical figures for the grade.
In practice 3.1 is the routine ask for pressure-retaining valve parts — body, bonnet, and often the closure member. It is what most plant and process purchase orders cite by default, because it gives traceable, material-specific evidence without putting an external inspector into the mill's schedule. When a datasheet says only "with mill cert", a 3.1 is almost always what the writer meant. Write the type, not the nickname.
Type 3.2 in plain terms
A 3.2 certificate reports the same kind of specific results with a second, external signature over them. Alongside the manufacturer's representative, a validator independent of the manufacturer countersigns: the purchaser's own inspector, or a third-party inspection body appointed for the job. That inspector verifies the testing against the order requirements before signing — which is why a 3.2 cannot be produced after the fact. The validation happens while the material is being made and tested, or it does not happen.
The practical meaning is simple. With a 3.1 you trust the manufacturer's internal separation of duties; with a 3.2, someone answering to you rather than to the mill has put their name on the same page. Sour service under NACE MR0175 and ISO 15156, offshore packages and safety-critical isolation duties are where that extra signature is routinely demanded.
On the page the difference is visible at a glance — the plate above draws it: one document sealed once, one carrying two distinct marks. Check both are actually present on a 3.2; a certificate titled 3.2 with only the manufacturer's stamp is a 3.1 wearing the wrong header.
Which orders need which
No rule maps services to document types — the project specification decides, and the usual caveat applies twice over: confirm against the current edition of EN 10204, and your purchase order governs. But the pattern across specifications is consistent enough to put on one card:
| SITUATION | REASONABLE ASK | WHY |
|---|---|---|
| Utility and non-critical lines | 2.2 or 3.1 | Traceability is useful; independence is rarely challenged |
| Pressure-retaining parts, process duty | 3.1 | Specific results with internal independence — the working default |
| Sour, offshore, safety-critical service | 3.2 | An external signature answers the auditor before the question is asked |
| Replacement in kind | Match the original | The line's documentation level decides, not the catalogue default |
Writing 3.2 on every line feels rigorous and mostly buys delay. Writing 2.1 everywhere saves nothing worth having. The honest question, line by line, is: who will ever challenge this material, and what evidence will satisfy them?
Cost and lead-time impact
The price of a 3.1 is close to invisible. Mills produce them as routine, and a stockist can normally supply a valve with the maker's 3.1 documentation from the same file the goods arrived with. A 3.2 is different in kind, not merely in degree: an inspection body must be appointed, scheduled into the manufacturer's test programme, attend or verify, and issue its countersignature. That coordination adds real lead time, and a fee that scales with where the mill is rather than with the size of your valve.
Independence cannot be added retrospectively — a 3.2 is decided before the tests are witnessed, or not at all.
That asymmetry is the whole decision. Upgrading paperwork after delivery ranges from painful to impossible, so over-asking costs days and money while under-asking on a critical line costs you a valve you cannot use. On a genuinely critical service, ask for the 3.2 and accept the lead time.
Wording for the purchase order
State the document type against each line item, not once in a footer: "Inspection certificate to EN 10204 type 3.1" — or type 3.2, naming who appoints the validator and who bears the attendance cost. Ask for certificates to travel with the delivery documents, and for heat numbers on the certificate to reconcile with the markings on the valve itself; that ten-second check is walked through in the nameplate memo. If the valve is also tested to API 598, say whether the test report belongs in the same document pack.
A stockist such as NF Teguh in Subang Jaya quotes against exactly these clauses — the clearer the documentation line, the faster the answer. How ordering works sets out the enquiry-to-delivery sequence, and the rest of the register lives in Insights.
Related memos
Standards named above are published reference data — confirm against the current edition; your purchase order governs. Questions: the counter.