EN 10204 Explained: 3.1 vs 3.2 Material Test Certificates

Quick Answer

EN 10204 is the European standard defining the types of inspection documents supplied with metallic products. It defines four types, and the difference between them is who tested, and who signed. Types 2.1 (declaration of compliance) and 2.2 (test report) are non-specific — they confirm the product meets the order, based on the manufacturer's routine production testing, but the results do not necessarily come from the material you received. Types 3.1 and 3.2 are specific inspection documents: the tests are performed on the actual product supplied, with full traceability to the heat or batch. The distinction between them is independence. A Type 3.1 certificate is issued by the manufacturer's own independent inspection representative — someone within the manufacturer's organisation but organisationally independent of production. A Type 3.2 certificate is validated jointly by the manufacturer's inspection representative and either the purchaser's inspection representative or a third-party inspector named in the order (Bureau Veritas, SGS, TÜV, Lloyd's). Type 3.1 is the industrial default for pressure equipment, oil and gas, and process piping. Type 3.2 is specified where independent verification is required — nuclear, critical pressure equipment, high-consequence service, or where a client, code, or authority mandates it. Whichever is specified, the certificate is only meaningful if the heat numbers on the certificate match the markings on the material.

Every serious industrial purchase order includes a line about certification, and it is usually written as "EN 10204 3.1" without further thought. But that line determines what you can actually prove about the steel in your plant — and in a failure investigation, or an audit, or a code inspection, the certificate is the only evidence you have that the material is what the drawing says.

The distinction that matters most is not obvious from the numbers. Types 2.1 and 2.2 are non-specific: they confirm that the product conforms to the order, but the test data comes from the manufacturer's routine production testing rather than from your batch. That is perfectly adequate for structural angle and general commercial material. It is not adequate for a pressure boundary.

Types 3.1 and 3.2 are specific: the tests were performed on the actual product supplied, and the certificate is traceable to the heat number stamped on the pipe. The difference between the two is independence — who witnessed and validated the testing.

Getting this wrong costs real money. Materials arriving with 2.2 certificates against a 3.1 requirement are rejected at goods-in and either returned or re-tested at cost. Materials with 3.1 certificates against a 3.2 requirement fail client audit. And certificates that cannot be reconciled to the physical markings on the material are worthless regardless of type.

For procurement managers, QA/QC engineers, inspectors, and project teams — this guide explains EN 10204 certificate types, what each one actually proves, when to specify 3.2, how to read and check an MTC, and the certificate problems that cause rejections.

For the materials these certificates accompany, see Carbon Steel Pipe, Stainless Steel Pipe, and Pipe Flanges.

The Four Certificate Types

EN 10204 classifies inspection documents into two families.

Non-Specific Inspection

Testing is carried out on products made by the same process as those supplied — but not necessarily on the actual items delivered.

Type 2.1 — Declaration of Compliance with the Order

• A simple statement by the manufacturer that the products comply with the order requirements
• No test results are provided
• Not traceable to your specific material
• Suitable for: general commercial material, non-critical structural items

Type 2.2 — Test Report

• The manufacturer declares compliance and supplies test results based on non-specific inspection
• Results come from routine production testing, not necessarily from your batch
• Still not traceable to the specific items delivered
• Suitable for: general engineering, non-pressure applications

The critical limitation of both: you cannot demonstrate that the numbers on the paper describe the metal in your hand.

Specific Inspection

Testing is performed on the actual products supplied, or on test units from the same batch or heat, with traceability.

Type 3.1 — Inspection Certificate 3.1

• Test results from specific inspection on the delivered product
• Validated by the manufacturer's authorised inspection representative, independent of the manufacturing department
• Full traceability to heat/batch number
• The industrial default for pressure equipment, piping, valves, flanges, and structural components in oil, gas, petrochemical, and power

Type 3.2 — Inspection Certificate 3.2

• Test results from specific inspection on the delivered product
• Validated jointly by the manufacturer's authorised inspection representative and either the purchaser's authorised representative or an inspector designated by official regulations — commonly a third-party inspection agency named in the order
• Provides independent verification of the testing
• Specified for high-consequence and regulated applications

Summary Table

When to Specify Which

Type 3.1 — The Default for Industrial Service

Specify 3.1 for:

• Pressure piping, fittings, flanges, and valves
• Pressure vessels and heat exchangers
• Oil, gas, petrochemical, refining, and power service
• Structural components in critical applications
• Anything where you may need to demonstrate material provenance later

In practice, 3.1 is what nearly every process industry specification calls for, and reputable manufacturers supply it as standard for these product categories.

Type 3.2 — Where Independence Is Required

Specify 3.2 when:

• Client, code, or regulatory requirement mandates third-party involvement
• Nuclear, defence, or safety-critical applications
• High-consequence service — extreme pressure, toxic media, sour service where failure risk is severe
• New or unproven supplier where independent verification is prudent
• Notified body involvement under PED or similar
• Contract terms require witnessed testing

Important practical point: 3.2 must be specified at order placement, because the third-party inspector has to be present during testing. It cannot be created retrospectively from an existing 3.1 certificate — a request that comes up regularly and always causes delay and cost. If there is any chance 3.2 will be required, specify it up front.

Cost and schedule impact: third-party inspection adds inspection fees, coordination time, and often mill scheduling delays. Budget for it.

What an MTC Should Contain

A usable Type 3.1 or 3.2 certificate typically shows:

Identification

• Manufacturer name and works
• Purchase order and item reference
• Product description, dimensions, and quantity
• Material specification and grade (e.g. ASTM A106 Gr B, EN 10216-2 P265GH)
• Heat / cast / batch number — the traceability key
• Delivery condition and heat treatment

Chemical composition

• Full elemental analysis (ladle and/or product analysis)
• Compared against specification limits
• For duplex and stainless, verify nitrogen is reported — it is frequently the element that gets omitted, and it drives PREN and weld toughness

Mechanical properties

• Yield strength, tensile strength, elongation
• Hardness where specified
• Impact (Charpy) test results with test temperature — essential for low-temperature and cryogenic service
• Flattening/bend test for pipe where applicable

Testing and examination

• Hydrostatic test pressure and result
• NDE performed (UT, RT, ET) and acceptance
• Surface and dimensional inspection

Special requirements as ordered

• NACE MR0175 / ISO 15156 compliance statement and hardness results for sour service
• PMI (Positive Material Identification) results
• Ferrite count for duplex
• Corrosion testing (e.g. ASTM G48) where specified
• Intergranular corrosion testing for stainless

Validation

• Signature, name, and position of the inspection representative
• For 3.2: the third-party inspector's stamp and signature
• Date and certificate number

How to Check a Certificate

The certificate is only as good as the checks performed on receipt.

1. Match the heat numbers. The heat/cast number on the certificate must match the marking stamped or printed on the physical material. This is the single most important check and the one most often skipped. A certificate that cannot be tied to the item is worthless.

2. Verify the specification and grade exactly — including the sub-grade and any supplementary requirements. "A105" and "A105N" are not the same.

3. Check every property against the specification limits. Do not assume the mill checked. Read the numbers.

4. Confirm the certificate type matches what the purchase order required. A 2.2 arriving against a 3.1 order is a rejection.

5. Verify special requirements are actually addressed. NACE compliance requires the hardness results to be present and within limits — a statement alone is not evidence. Impact testing requires the test temperature to be stated.

6. Check the delivery condition and heat treatment. Solution annealed and quenched for duplex and austenitic stainless; normalised for many carbon steels. This is a common gap.

7. Confirm signatory independence. For 3.1, the signatory should be the inspection function, not production. For 3.2, the third-party stamp must be present.

8. Cross-check with PMI where required. Positive Material Identification on receipt verifies the alloy independently of the paperwork, and is standard practice for stainless and alloy materials.

Related Standards and Terminology

"Mill Test Certificate" (MTC) / "Mill Test Report" (MTR) — general industry terms for the material certificate. MTR is more common in North American practice; MTC in European. Both usually mean an EN 10204 3.1 equivalent in practice, but the standard and type should always be stated explicitly rather than relying on the abbreviation.

ASTM A960 / A961 and product specifications set their own certification requirements, which projects usually satisfy by specifying EN 10204 types alongside.

PED (Pressure Equipment Directive) — European pressure equipment requires materials with appropriate certification; 3.1 is typically minimum, with 3.2 where the notified body or category requires it.

AD 2000-Merkblatt W0 — German pressure vessel material rules referencing EN 10204 documentation.

Common Certificate Problems

After 15+ years supplying certified materials to industrial projects:

Problem 1: Heat Numbers Don't Match

Certificate supplied but the heat number does not appear on the material, or differs. Traceability is broken and the material cannot be accepted for pressure service.

Prevention: Check on receipt, before offloading if possible. Require heat marking on every piece, and a packing list mapping items to heats.

Problem 2: 2.2 Supplied Against a 3.1 Order

Material arrives with a test report rather than a specific inspection certificate — often because "certificate" was written on the PO without the type.

Prevention: State the exact requirement on the purchase order: "EN 10204 Type 3.1". Verify at order acknowledgement, not at delivery.

Problem 3: 3.2 Requested After Delivery

Client or authority requires 3.2 late in the project. It cannot be produced retrospectively because third-party witnessing had to occur during testing.

Prevention: Establish certification requirements at specification stage. If 3.2 is possible, specify it from the start.

Problem 4: Missing Nitrogen on Duplex Certificates

Duplex or super duplex certificate omits nitrogen content. PREN cannot be calculated and weld-zone toughness cannot be assessed.

Prevention: Explicitly require full chemistry including nitrogen for duplex grades, and check it on receipt. See Duplex & Super Duplex Pipe.

Problem 5: NACE Statement Without Hardness Data

Certificate states NACE MR0175 compliance but contains no hardness results. The claim is unverifiable and will fail audit.

Prevention: Require hardness test results on the certificate for all sour service materials, with the values within MR0175 limits.

Problem 6: Impact Test Temperature Not Stated

Charpy results provided but no test temperature. For low-temperature or cryogenic service the data is meaningless.

Prevention: Specify the required impact test temperature and energy in the purchase order and verify both appear on the certificate.

Problem 7: Heat Treatment Condition Missing

Delivery condition not stated. For duplex, austenitic stainless, and normalised carbon steels, the heat treatment is what establishes the properties.

Prevention: Require the delivery condition and heat treatment record (temperature and cooling method) on the certificate.

Problem 8: Relying on Paperwork Alone

Certificates accepted without any physical verification. Material grade errors — genuine mix-ups as well as fraud — pass into the plant.

Prevention: PMI on receipt for all stainless and alloy materials. It is fast, inexpensive, and independent of the paperwork.

Supply from Kasko Makine

Kasko Makine supplies certified materials for oil & gas, petrochemical, power, water, and industrial projects, with documentation to project requirements:

Standard certification supplied:

• EN 10204 Type 3.1 material test certificates as standard on pressure and process materials
• EN 10204 Type 3.2 with third-party inspection (Bureau Veritas, SGS, TÜV, Lloyd's) where specified
• Full chemical analysis including nitrogen for duplex grades
• Mechanical properties: yield, tensile, elongation, hardness
• Charpy impact testing with stated test temperature
• Hydrostatic test records
• NDE reports (UT, RT, ET) per PO/ITP
• Heat treatment records (temperature and cooling)
• Heat number traceability lists mapping every item to its heat
• PMI reports for stainless and alloy materials
• NACE MR0175 / ISO 15156 compliance with supporting hardness data
• Ferrite count for duplex; ASTM G48 corrosion testing where specified
• Dimensional inspection reports
• Certificates of origin

Product range covered: pipe, fittings, flanges, valves, plate, structural sections, fasteners, gaskets, heat exchangers, pressure vessels, and tanks.

Documentation support:

• Certificate review against your specification before shipment
• Consolidated documentation dossiers per purchase order
• Traceability lists for fabrication and construction records
• Coordination of third-party inspection scheduling for 3.2 requirements
• Support for client, notified body, and authority audits

Practical advice we provide: confirming whether 3.1 or 3.2 is genuinely required for your application, and flagging where 3.2 needs to be specified before order placement to avoid retrospective problems.

Logistics: Certified materials shipped from Istanbul to projects across Africa, the Middle East, Central Asia, and beyond. Documentation dossiers supplied with shipment and electronically in advance where required.

Need materials with full EN 10204 certification? Send us your material specification and grade, quantities, required certificate type (3.1 or 3.2), any third-party inspection requirement, and special testing (NACE, impact, PMI, corrosion testing) to info@kaskomakine.com or WhatsApp +90 (537) 521 1399. We'll confirm what certification is available, advise where 3.2 needs to be arranged in advance, and provide a quotation within 48 hours.

Continue Reading: Materials & Specification Guides

• Carbon Steel Pipe — Grades and specifications
• Stainless Steel Pipe — Austenitic grades
• Duplex & Super Duplex Pipe — Certificate requirements including nitrogen
• Pipe Flanges — Flange material certification
• Industrial Valves Guide — Valve certification
• Chemical Reactors & Pressure Vessels — ASME documentation packages
• Flange Bolt Torque & Joint Assembly — ASME PCC-1 bolt-up procedure
• Corrosion Under Insulation (CUI) — Material selection for insulated lines

Frequently Asked Questions

Q: What is EN 10204?
A: EN 10204 is the European standard that defines the types of inspection documents supplied with metallic products. It classifies certificates into two families. Non-specific inspection documents — Type 2.1 (declaration of compliance with the order, with no test results) and Type 2.2 (test report with results from routine production testing) — confirm conformity but are not traceable to the specific items delivered. Specific inspection documents — Type 3.1 and Type 3.2 — contain test results from inspection performed on the actual product supplied, with traceability to the heat or batch number. The standard is referenced worldwide, not only in Europe, and is the normal way industrial purchase orders express certification requirements.

Q: What is the difference between EN 10204 3.1 and 3.2?
A: Both are specific inspection certificates, meaning the test results come from the actual product supplied with traceability to the heat number. The difference is independence of validation. A Type 3.1 certificate is issued and validated by the manufacturer's authorised inspection representative, who must be organisationally independent of the manufacturing department but is still part of the manufacturer's organisation. A Type 3.2 certificate is validated jointly by the manufacturer's inspection representative and either the purchaser's authorised representative or an inspector designated by official regulations — in practice usually a third-party inspection agency such as Bureau Veritas, SGS, TÜV, or Lloyd's named in the purchase order. Type 3.1 is the industrial default; 3.2 is specified where independent verification is required.

Q: When do you need a 3.2 certificate?
A: Type 3.2 is specified where independent third-party verification of testing is required: when a client, code, or regulation mandates it; for nuclear, defence, and safety-critical applications; for high-consequence service such as extreme pressure, toxic media, or severe sour service; when using a new or unproven supplier; where a notified body is involved under the Pressure Equipment Directive; or where contract terms require witnessed testing. Critically, 3.2 must be specified at order placement because the third-party inspector must be present during testing — it cannot be produced retrospectively from an existing 3.1 certificate. It also adds inspection fees, coordination time, and often mill scheduling delays, so it should be budgeted and planned in advance.

Q: What should a material test certificate contain?
A: A usable Type 3.1 or 3.2 certificate should show identification details (manufacturer, purchase order reference, product description and dimensions, material specification and grade, heat or cast number, delivery condition and heat treatment); full chemical composition compared against specification limits; mechanical properties including yield strength, tensile strength, elongation, hardness where specified, and Charpy impact results with the test temperature stated; testing and examination records including hydrostatic test and NDE results; any special requirements as ordered such as NACE MR0175 compliance with supporting hardness data, PMI results, ferrite count for duplex, or corrosion testing; and validation with the signature, name, and position of the inspection representative, plus the third-party stamp for Type 3.2.

Q: How do you verify a material test certificate?
A: The single most important check is matching the heat or cast number on the certificate to the marking stamped or printed on the physical material — a certificate that cannot be tied to the item is worthless. Beyond that: verify the specification and grade exactly, including sub-grades and supplementary requirements; check every reported property against specification limits rather than assuming the mill did; confirm the certificate type matches what the purchase order required; verify that special requirements such as NACE compliance are supported by actual hardness data rather than a bare statement; confirm the delivery condition and heat treatment are recorded; check that the signatory represents the inspection function; and perform Positive Material Identification on receipt for stainless and alloy materials as an independent physical check.

Q: Is a mill test certificate the same as EN 10204 3.1?
A: "Mill Test Certificate" (MTC) and "Mill Test Report" (MTR) are general industry terms for the document a manufacturer supplies with material — MTR is more common in North American practice and MTC in European. In everyday usage they usually refer to something equivalent to an EN 10204 Type 3.1 certificate, but the terms themselves carry no defined meaning under the standard. A supplier can legitimately describe a Type 2.2 test report as a "mill certificate". For this reason, purchase orders should always state the standard and type explicitly — for example "EN 10204 Type 3.1" — rather than relying on abbreviations, and the requirement should be verified at order acknowledgement rather than discovered at delivery.