EN 10204 3.1 vs 3.2 Inspection Certificates

Both EN 10204 type 3.1 and type 3.2 are inspection certificates containing results from specific inspection. The main difference is not the steel grade or the number of tests. It is who validates the inspection document.

This distinction is frequently misunderstood in steel purchasing, where “3.2” is sometimes used as shorthand for “better material” or “all tests witnessed by a third party.” Neither statement is automatically correct.

The core difference

EN 10204 is an inspection-document standard. It is normally used together with the applicable product standard and the purchase order, which define what has to be tested and on what test unit.

What is a 3.1 certificate?

A type 3.1 certificate contains the manufacturer's declaration that the supplied products comply with the order, together with results of the required specific inspection.

The certificate is validated by the manufacturer's authorized inspection representative who is independent of the manufacturing department.

In practical steel procurement, a 3.1 MTC commonly contains items such as:

• manufacturer and works;
• PO/order references;
• product standard and grade;
• dimensions and quantity;
• heat/cast number and other traceability identifiers;
• chemical composition;
• mechanical test results;
• impact testing where required;
• NDT or other test references where required;
• delivery condition;
• declaration/signature or electronic validation.

The exact content comes from the combination of EN 10204, the product specification and the order.

What changes with 3.2?

Type 3.2 adds another level of independent validation. The document is validated by the manufacturer's authorized inspection representative and either:

• the purchaser's authorized inspection representative; or
• an inspector designated by official regulations.

In commercial practice, an independent inspection body such as a class society or TPI organization often performs this role, but EN 10204 does not make a particular commercial TPI company part of the certificate name.

Does 3.2 mean the inspector must witness every test?

Not automatically.

The certificate type establishes the inspection-document and validation framework. The required hold points, witness points, document reviews, test witnessing and intervention scope are determined by the purchase order, ITP, project specification, regulatory route or agreement with the inspector.

A project may require the inspector to witness material sampling, tensile testing, Charpy testing, UT or final marking. Another order may define a different intervention plan. The number “3.2” alone does not define that entire inspection plan.

This is an important RFQ point: if the client wants specific witnessing, say so explicitly rather than assuming “3.2” communicates all of it.

Is 3.2 “better steel” than 3.1?

No. Certificate type and material quality are different concepts.

A pipe made to the same grade, chemistry, mechanical properties and test requirements does not acquire higher strength or toughness merely because a 3.2 certificate is issued. What changes is the independent validation route and associated assurance.

A demanding project can require both a stringent material specification and a 3.2 inspection certificate. Those are separate requirements.

Can a 3.1 be upgraded to 3.2 after production?

Do not assume that it can.

If the required 3.2 route involved agreed witnessing, identification controls or inspection interventions during production, those steps cannot simply be recreated by changing the certificate heading after the event. In some circumstances an independent inspector may be able to validate existing records and perform additional verification, but whether that satisfies the PO is a project-specific question.

If 3.2 is required, it is safer to establish the inspection arrangement before production starts.

3.1/3.2 does not replace the product standard

An MTC saying “EN 10204 3.2” is incomplete as a technical material requirement. The order still needs the product specification, such as EN 10025, EN 10210, EN 10216, API 5L or another applicable standard.

Similarly, 3.2 does not by itself mean:

• DNV/ABS/LR approved material;
• a specific NDT class;
• impact testing at a particular temperature;
• sour-service compliance;
• CE marking;
• PED compliance;
• offshore qualification;
• a specific test frequency.

Each of those requirements must be established separately.

Practical buyer checklist

When a client asks for 3.2, confirm:

1. Who is permitted to act as the additional inspector?
2. Is a named TPI or class society required?
3. Which tests must be witnessed?
4. Are there hold/witness/review points in an ITP?
5. Must identification or stamping be witnessed?
6. Who pays the inspection cost?
7. Is the mill able to accommodate the inspector during production?
8. Does the required certificate apply to the mother material, finished product or both?
9. Is re-testing by an independent laboratory required?
10. Which standard edition and project specification define the test unit and acceptance criteria?

MetalMate takeaway

3.1 and 3.2 are both specific-inspection certificates. The defining extra feature of 3.2 is additional independent validation — not automatically different steel, more tests or universal third-party witnessing. Put the required inspection interventions in the PO/ITP explicitly.

References

• NEN, EN 10204:2004 — Metallic products — Types of inspection documents: https://www.nen.nl/en/nen-en-10204-2004-en-95076
• British Stainless Steel Association, BS EN 10204 test certificates for stainless steel products: https://bssa.org.uk/bssa_articles/bsen-10204-test-certificates-for-stainless-steel-products/
• TÜV Rheinland, Testing and Certification Regulations — acceptance testing of metallic materials / EN 10204 3.2: https://www.tuv.com/content-media-files/germany/pdfs/tuv-rheinland-allgemeine-gesch%C3%A4ftsbedingungen/industrial-service/tuv-rheinland-industrie-service-gmbh/tuev-rheinland-a-011-e-pzo-gf-i01-rev31_extsigned.pdf