How to read an EN 10204 3.1 mill certificate for steel tubes
What the EN 10204 inspection document types 2.1, 2.2, 3.1 and 3.2 mean, what a 3.1 certificate for hollow sections contains, and a checklist for checking it against the delivery.
Updated October 16, 2026
A mill certificate is the proof that the steel you receive is the grade you ordered. EN 10204 defines the types of inspection document for metallic products. Most structural projects ask for a 3.1 certificate. This guide explains the types and how to check a 3.1 certificate for hollow sections.
Inspection document types
| Type | Name | Test results | Validated by |
|---|---|---|---|
| 2.1 | Declaration of compliance with the order | None | The manufacturer |
| 2.2 | Test report | Non-specific inspection: tests on similar products | The manufacturer |
| 3.1 | Inspection certificate 3.1 | Specific inspection: tests on the delivered products or their test unit | The manufacturer’s authorised inspection representative, independent of production |
| 3.2 | Inspection certificate 3.2 | Specific inspection, as 3.1 | The manufacturer’s representative and the purchaser’s representative or an inspector named in the regulations |
The difference that matters: types 2.1 and 2.2 do not show tests on your material. A 3.1 certificate shows results from the heat and test unit your tubes came from. A 3.2 certificate adds an independent witness, so it costs more and takes longer. Order it only when the specification asks for it.
What a 3.1 certificate for hollow sections shows
- Header — manufacturer, certificate number and date, the document type (EN 10204 3.1), the purchaser and order reference.
- Product — product standard and grade, for example EN 10219-1 S355J2H; dimensions (h × b × t or D × t), lengths, number of pieces and mass.
- Heat (cast) number — links each tube to the steel it was made from. The same number is marked on the tubes or bundle labels.
- Chemical composition — the cast analysis, usually C, Si, Mn, P, S and other elements, and often the carbon equivalent (CEV).
- Tensile test — yield strength (ReH or Rp0.2), tensile strength (Rm) and elongation (A%).
- Impact test — Charpy V-notch energies and the test temperature, for grades where it is required (J0H at 0 °C, J2H at −20 °C) and where the wall is thick enough for a specimen.
- Other tests — dimensions and visual inspection, and non-destructive testing of the weld seam where the standard or order requires it.
- Statement and signature — confirmation that the products meet the order, signed by the authorised inspection representative.
Checklist: checking a certificate against the delivery
- The document type is 3.1 (or 3.2 if that was ordered), not 2.1 or 2.2.
- The standard and the full grade name match the order: S355J2H is not S355JRH or S355.
- Sizes, walls and quantities on the certificate cover what was delivered.
- The heat numbers marked on the tubes or bundle labels appear on the certificate.
- Yield, tensile and elongation results are at or above the minimums of the grade. For EN 10219 grades see Hollow section steel grades.
- For J0H and J2H grades, impact results are given at the right temperature and meet 27 J.
- Chemical values are within the limits of the standard, and the CEV meets any limit in your specification.
- The certificate is signed and the signatory is identified.
Certificates and CE marking
In the EU, structural hollow sections to EN 10219-1 are construction products under a harmonised standard. They carry CE marking and come with a declaration of performance (DoP). The DoP covers the product type; the 3.1 certificate covers your delivery. Fabricators working to EN 1090 usually need both for traceability.
Ordering certificates
State the document type in your request, for example "EN 10204 3.1 for all items", together with the standard, grade, sizes and quantities. We confirm what is available for each heat and product in our reply to your quote request.
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