Type 2.1 — declaration of compliance
A statement by the manufacturer that the material supplied complies with the requirements of the order. No test results, no measured values, no heat analysis. It is a commercial document, not a technical one.
It is legitimate and it has a place — commodity product, no traceability requirement, no downstream customer asking questions. It is not a substitute for a 3.1 and it should not be accepted where one was specified.
Type 2.2 — test report
A statement of compliance that refers to tests, but based on non-specific testing: results from the production run or from routine quality control, not from the specific heat or batch you are buying.
This is the one to watch. A 2.2 document looks like a certificate, is filed like a certificate and is frequently quoted as one. The wording to look for is any indication that the values are typical or representative rather than from your material. If your project has a classification society, an aerospace customer or a pressure vessel code behind it, 2.2 will be rejected at some point — usually at the worst point.
Type 3.1 — inspection certificate
Test results from specific inspection of the material supplied, with the heat or batch identified, signed by the manufacturer's authorised inspection representative. The signature matters: that representative has to be independent of the production department, which is the structural reason a 3.1 carries weight that a 2.2 does not.
A 3.1 for aluminium normally carries the heat analysis (the chemical composition by element) and the mechanical test results — tensile strength, yield strength and elongation — plus the standard, the alloy, the temper, the dimensions and the quantity. Check that the heat number on the certificate matches the heat number on the material marking. That is the traceability link, and it is the whole point.
Type 3.2 — third-party verified
A 3.1 additionally verified and countersigned by a party independent of the manufacturer: the buyer's own representative, or a third party such as a classification society or inspection body. Where a project specification calls for DNV, LR, ABS or a similar body, this is the certificate type it is asking for.
3.2 costs more and takes longer because someone has to be present. It is worth specifying only when something downstream requires it. Where nothing does, a 3.1 is the sensible default.
What to write into the order
- Name the type: "EN 10204 3.1 inspection certificate" — not "MTC", not "certificate of compliance".
- Require the heat number on both the certificate and the material or package marking.
- Say which standard the properties are reported against, so the numbers mean something.
- If the project has a certifying body behind it, name the body and ask for 3.2 before quoting, not after production.
- Ask to see a sample certificate before you order. A supplier who sends one is telling you what you will receive.
Comparison table
| Type | Name | Test data | Signed by | Typical acceptance |
|---|---|---|---|---|
| 2.1 | Declaration of compliance | None | Manufacturer | Commodity, no traceability requirement |
| 2.2 | Test report | Non-specific (routine/typical) | Manufacturer | General industrial; rejected where traceability is required |
| 3.1 | Inspection certificate | Specific, per heat/batch | Manufacturer inspector independent of production | Default for engineered and export orders |
| 3.2 | Inspection certificate, verified | Specific, per heat/batch | Manufacturer plus buyer rep or third party | Marine class, aerospace, pressure equipment |
We state the certificate type on the quotation rather than leaving it to be discovered. If your project genuinely needs 3.2, tell us at enquiry stage — arranging third-party attendance during production is possible and is not something to add after the mill has scheduled the rolling.