EN 10204: the material certificate standard
EN 10204 defines four types of material test documents for metallic products. In valve procurement, the relevant types are 2.2, 3.1 and 3.2. Type 2.1 (declaration of compliance) is rarely sufficient for industrial valve components; Type 3.2 is the most demanding.
The key distinction between types is who issues the certificate and what it is based on. Type 2.2 (test report) is issued by the manufacturer based on non-specific inspection and testing. Type 3.1 (inspection certificate) is issued by the manufacturer's authorised inspection representative, based on tests specific to the batch of material. Type 3.2 is issued by both the manufacturer's authorised representative and an independent third-party inspection body.
EN 10204 types compared
| Type | Issued by | Based on | Typical use |
|---|---|---|---|
| 2.2 | Manufacturer | Non-specific testing | General commercial valves, water service |
| 3.1 | Mfr authorised inspector | Specific lot testing | Process valves, oil and gas, standard industrial |
| 3.2 | Mfr inspector + TPI | Specific lot testing, witnessed | Critical service, nuclear, offshore, high P-T |
What EN 10204 3.1 certificates cover
An EN 10204 3.1 certificate (often called a "3.1 mill cert" or "3.1 MTC") shows the material heat number, chemical composition from ladle analysis, mechanical test results (yield strength, tensile strength, elongation and impact values if specified), and the authorised signature from the manufacturer's quality department.
The certificate traces to the specific heat of material used for the valve body and other pressure-retaining parts. For valve orders requiring 3.1 certificates, the purchase order must state this requirement explicitly: it cannot be added after manufacture begins and the material may not be traceable if certificates are requested after the fact.
Impact testing results (Charpy values) should be present on 3.1 certificates for valves specified for low-temperature service. Confirm the test temperature and minimum impact energy requirement match your design specification.
EU Declaration of Conformity and CE marking
Valves placed on the EU market above the exclusions in the Pressure Equipment Directive (PED 2014/68/EU) must be CE marked and accompanied by a Declaration of Conformity. The PED exclusion thresholds depend on the fluid category (hazardous or non-hazardous) and the product of pressure and volume (or pressure and DN for pipework). Many industrial valves above DN25 in Group 1 fluids (hazardous) are within PED scope.
The Declaration of Conformity declares that the product meets the Essential Safety Requirements of the PED, states the conformity assessment route used (typically Module A for lower-risk valves up to Category II, Module H for Category III and IV), and identifies the Notified Body (if applicable). It is signed by the manufacturer and is part of the technical file that must be retained for 10 years.
CE marking does not mean the valve meets your specific application requirements — it means the manufacturer has declared conformity with the PED. Verify the actual technical specification independently.
Positive material identification (PMI)
Positive material identification (PMI) is a non-destructive technique (typically X-ray fluorescence, XRF) that verifies the chemical composition of a metal component against its specified material grade. It is used to confirm that the correct alloy has been used in manufacture, as an independent check on the mill certificate, or when the material traceability chain is uncertain (for example, on second-hand or unmarked components).
PMI testing is required by some operator standards (particularly in oil and gas and chemical industries) on a percentage or 100% basis for high-alloy materials: stainless steel, duplex, Inconel, Hastelloy and other expensive or safety-critical alloys where substitution with a cheaper grade would be difficult to detect visually. Specify PMI requirements in the purchase order if your project or operator standard requires it.
XRF can identify most elements reliably but has limitations for some light elements (carbon, nitrogen) and may not distinguish between closely related grades. For critical alloy verification, complementary optical emission spectrometry (OES) or wet chemical analysis may be specified.