EN 10204 3.1 vs 3.2 Certificate Which Do You Need for Your Project?

Every batch of steel or nickel alloy you purchase should arrive with a material test certificate - a document that proves the metal inside the pipe or plate is exactly what you ordered. In Europe and across many international projects, this certificate follows the EN 10204 standard.

Two certificate types dominate industrial procurement: Type 3.1 and Type 3.2. The difference seems subtle - but ordering the wrong type can lead to real consequences:

Rejection by regulatory body - EU notified bodies will reject PED Category III/IV equipment without a 3.2
Insurance voided - many industrial insurers require 3.2 for pressure-bearing equipment
Project delays - post-delivery discovery of wrong certificate type forces re-testing or replacement
Legal liability - in sour service failures, inability to prove 3.2 compliance can shift fault to the buyer

EN 10204 31 vs 32 Certificate

This guide breaks down every dimension of the difference so you can specify the right certificate every time - and defend that specification to procurement, legal, and project teams.

EN 10204 is a European Standard titled "Metallic Products - Types of Inspection Documents," published by CEN (European Committee for Standardization). The current version dates from 2004 and has been adopted as a national standard throughout EU member states (DIN EN 10204, BS EN 10204, NF EN 10204, etc.).

It is referenced by ASME (Supplement S), API, NACE/ISO 15156, PED 2014/68/EU, and classification societies worldwide - making it the de facto global standard for material certification.

Type	Name	Data Basis	Validated By	Use Case
2.1	Declaration of Compliance	No test data - compliance declaration only	Manufacturer	Low-risk, non-critical commercial parts
2.2	Test Report	Non-specific / statistical sampling results	Manufacturer	Structural, general engineering components
3.1 ★	Inspection Certificate 3.1	Heat/cast-specific chemical + mechanical test data	Manufacturer's authorized QC rep (independent of production)	Oil & gas, chemical, food/pharma, standard PV
3.2 ★★	Inspection Certificate 3.2	Same as 3.1 - heat/cast-specific data	Manufacturer's rep + purchaser-nominated 3rd-party inspector	Nuclear, sour service, PED Cat III/IV, marine class, defense

"A document in which the manufacturer declares that the products supplied are in compliance with the requirements of the order and in which he supplies test results. The test unit and the tests to be carried out are defined by the product specification, the official regulations, and corresponding rules and/or the order. The test results are validated by the manufacturer's authorized representative who is independent of the manufacturing department."

Required Field	Description	Example
Product identification	Grade, product form, dimensions, standard	316L seamless pipe, 2" Sch 80, ASTM A312 TP316L
Heat / cast number	Unique identifier linking to ladle analysis	Heat No. 7BK4421
Purchase order reference	Links certificate to commercial transaction	PO No. 20260101-05
Chemical composition (actual)	As-produced ladle analysis - all elements per applicable standard	C 0.019%, Cr 16.8%, Ni 10.4%, Mo 2.14%, N 0.05%
Mechanical properties (actual)	Tensile, yield, elongation, hardness as required by standard	YS 230 MPa, UTS 588 MPa, El 43%, HRB 75
Heat treatment condition	Process + temperature + quench medium	Solution annealed at 1,080°C, water quenched
NDT results (if required)	Hydrostatic, UT, ET per applicable standard	Hydrostatic per ASTM A530: pass
Compliance declaration	Statement that product meets order requirements	Signed declaration of compliance
Authorized representative signature	Signature + name + title; must be independent of production dept.	J. Smith, QA Manager (independent of production)

"A document in which the manufacturer declares that the products supplied are in compliance with the requirements of the order and in which test results are validated by the manufacturer's authorized representative and either the purchaser's authorized representative or the inspector designated by the official regulations."

The critical addition: a second independent signature from a party nominated by the purchaser - not the manufacturer. This inspector witnesses the actual tests in real time, adding an independent audit trail that is legally and regulatorily far more robust.

Signatory Type	Examples	Typical Regulatory Context
EU Notified Body	TÜV SÜD, Bureau Veritas, Lloyd's Register, DNV GL	PED 2014/68/EU, ATEX 2014/34/EU - mandatory for Cat III/IV
Classification Society	ABS, DNV, LR, BV, NK, KR, CCS, RINA	Marine/offshore per IMO, SOLAS, class rules
Purchaser-nominated TPI	SGS, Intertek, CCIC, Velosi, Applus+	NACE MR0175 sour service, API 5L PSL2, ASME Sec VIII Div 2
Statutory Inspector	National nuclear authority inspector	Nuclear pressure equipment, IAEA standards, RCC-M, KTA
Purchaser's own authorized inspector	End-user QA engineer meeting independence criteria	Large EPC / major oil companies; military/defense procurement

Standard / Regulation	Requirement	Risk if 3.1 Used Instead
PED 2014/68/EU - Category III & IV	Inspection Certificate 3.2 (notified body co-sign)	Equipment cannot be CE-marked; cannot be sold in EU
NACE MR0175 / ISO 15156 (H₂S sour service)	3.2 strongly recommended; project specs often mandate it	Brittle fracture risk; legal liability in failure
API 6A:2018 PSL 3/4 (wellhead & Xmas tree)	3.2 required at PSL 3 and PSL 4	Does not meet PSL qualification requirements
API 5L:2018 PSL 2 (line pipe - sour / offshore)	3.2 for purchaser's representative witness	Non-compliant with PSL 2 inspection requirements
ASME BPVC Section VIII Div. 2	Purchaser's Inspector witness (functionally 3.2-equivalent)	Vessel code compliance issue; jurisdiction authority rejection
Nuclear installations (RCC-M, KTA 3201, IAEA)	3.2 mandatory - nuclear-grade documentation chain	Complete documentation non-conformance; safety license risk
Marine/Offshore class (DNV, ABS, LR, BV)	3.2 for hull steel, pressure piping, safety-critical components	Class society will not issue certificate of compliance
UK PSSR 2000 (post-Brexit)	3.2 recommended for Cat III/IV equivalent systems	UKAS-recognized body requirements not met
Aerospace (NADCAP, AS9100)	3rd-party witness / 3.2 equivalent as part of MRB package	Airworthiness compliance issue

Dimension	Type 3.1	Type 3.2
Inspector appointed by	Manufacturer	Purchaser or purchaser-nominated authority
Inspector independence	Independent from production department	Independent from production + purchaser-approved
Test witnessing	Not required - QC review of documented results	Third-party witnesses actual tests in real time
Number of signatories	1 (manufacturer's QC representative)	2 (manufacturer + independent party)
Certificate data content	Heat-specific chem. + mech. + NDT	Identical data - same scope as 3.1
Traceability	Heat/cast linked to certificate	Heat/cast linked to cert + independent TPI audit records
Falsification deterrence	Moderate - single internal signature	High - independent co-signature; legally harder to falsify
Cost premium vs. 3.1	Baseline (zero or minimal)	+15%–40% (TPI mobilization + standby + travel)
Lead time impact	No significant addition	+3–10 working days (TPI scheduling)
Regulatory code trigger	PED Cat I–II, ASME B31.3, general O&G	PED Cat III–IV, sour service, nuclear, marine class
Re-issue process	Manufacturer re-issues after re-test	TPI + manufacturer must jointly re-sign
Legal weight in litigation	Moderate - internal validation only	High - independent third-party corroboration

Use the following structured decision flow to determine the correct certificate type for your project:

Step 1 - Identify Your Applicable Code

If Your Project Is...	Certificate Needed	Typical Minimum
General commercial fabrication, non-pressure	Type 2.2 or 3.1	EN 10204 §2.2 minimum; 3.1 preferred
Standard pressure vessels - PED Category I–II	Type 3.1	EN 10204 §3.1
PED Category III–IV pressure equipment (EU/EEA)	Type 3.2	EN 10204 §3.2 + Notified Body co-sign
ASME B31.3 Standard Fluid Service piping	Type 3.1	ASME B31.3 §A323.2
ASME B31.3 Category M (toxic) or Category D high-purity	Type 3.1 minimum; 3.2 recommended	Project spec governs
ASME BPVC Sec. VIII Div. 2 (high-pressure vessels)	Type 3.2 (Purchaser's Inspector)	ASME UG-90/UG-91
NACE MR0175/ISO 15156 - H₂S sour service	Type 3.2	Project specifications universally require 3.2
API 5L PSL 2 (offshore / sour service pipelines)	Type 3.2	API 5L Table E1 inspection requirements
API 6A PSL 3 / PSL 4 (wellhead / Xmas tree)	Type 3.2	API 6A §5.2 (product specification level)
Marine / offshore classification (ABS, DNV, LR, BV)	Type 3.2	Class society rules; classification society signs as 2nd party
Nuclear power plant components	Type 3.2 mandatory	RCC-M, KTA 3201, or national nuclear authority standard
Food & beverage / pharmaceutical - non-pressure use	Type 3.1	ASME BPE / 3-A / FDA 21 CFR 177
Defense / military procurement	Type 3.2 (minimum)	DFARS / MIL-SPEC contract requirements

Step 2 - Check Your Contract and Purchase Order

Always cross-check three sources before specifying the certificate type in your purchase order:

Your project specification (issued by the EPC contractor or end-user)
The applicable regulatory code (PED, ASME, API, NACE, etc.)
Your company's purchasing standard or approved vendor list requirements

If your PO does not explicitly specify 3.1 or 3.2, many suppliers will default to Type 3.1 even if your project requires 3.2. Always state the certificate type explicitly in your purchase order.

Upgrading from a 3.1 to a 3.2 certificate involves real costs and timeline impacts. Understanding these helps you budget correctly and avoid delays.

Cost Driver	Typical Range	Notes
TPI daily rate (witness inspection)	USD 400–900 per inspector-day	Varies by agency, location, and material value
TPI travel and accommodation	USD 300–800 per trip	Especially relevant for overseas mills
Standby time (if production delays)	USD 200–500 per standby day	Can be mitigated by production readiness review
Certificate issuance / admin fee	USD 50–200 per heat	TPI document management
Total 3.2 premium (typical range)	15%–40% of 3.1 certification cost	For a standard pipe order; varies by volume and mill
Re-test cost if TPI witnesses a failure	Production re-run + full re-test cycle	Major cost driver - quality control is critical upstream

Lead Time Impact

Activity	Additional Time vs. 3.1	Mitigation
TPI scheduling / mobilization	+2–5 working days	Pre-book inspector in advance when PO is placed
Inspector review of mill's inspection plan	+1–2 working days	Submit inspection test plan (ITP) with PO
Coordination of witness window	+0–3 working days	Align mill production schedule with TPI calendar
Certificate co-signing and issuance	+1–2 working days	Electronic co-signing available with major TPI firms
Total typical 3.2 lead time premium	+3–10 working days vs. 3.1	Plan at project kickoff, not at procurement stage

Vague or incomplete PO wording is the most common cause of certificate disputes. Use the following templates:

For Type 3.1 - Recommended PO Wording

"Material to be supplied with EN 10204:2004 Type 3.1 Inspection Certificate covering chemical analysis (actual ladle values), mechanical properties, heat treatment condition, and non-destructive test results as required by [ASTM A312 / EN 10216-5 / applicable material standard]. Certificate to be signed by manufacturer's authorized representative independent of the production department."

For Type 3.2 - Recommended PO Wording

"Material to be supplied with EN 10204:2004 Type 3.2 Inspection Certificate. Tests to be witnessed by [Purchaser's authorized inspector / Bureau Veritas / TÜV SÜD / Lloyd's Register - specify as applicable], nominated by Purchaser. Certificate to bear dual signature of (1) manufacturer's authorized QC representative and (2) Purchaser's nominated third-party inspector. Inspection Test Plan (ITP) to be submitted to Purchaser for approval minimum 10 working days prior to scheduled production. All test reports and certificate copies to be provided in English."

Common PO Specification Mistakes to Avoid

Mistake	Why It Is a Problem	Correct Approach
Specifying "EN 10204 certificate" without 3.1/3.2	Supplier defaults to 2.2 or 3.1	Always state "3.1" or "3.2" explicitly
Specifying 3.2 without naming the TPI	Supplier selects cheapest/fastest TPI; may not be accepted by end-client	Name the approved TPI in the PO or have purchaser nominate one
No ITP requirement in PO	TPI has no inspection test plan; witness scope is undefined	Require ITP submission and approval before production
No language requirement for certificate	Certificate issued in local language; auditor cannot verify	Require English (or bilingual) certificate
Specifying 3.1 when project code requires 3.2	Regulatory non-compliance; potential rejection post-delivery	Check applicable code before issuing PO
No certificate authenticity verification clause	Fraudulent certificates difficult to challenge without prior basis	Require mill co-signature + TPI contact details for verification

Certificate fraud exists in the metals industry. A 2023 international metals fraud investigation found that fraudulent MTRs are more common in spot-market procurement. Here is how to verify authenticity:

Verification Step	How to Do It	Red Flag
Check signatory details	Call the mill's QA department directly; verify the signatory name and title exist	Signatory name does not appear in mill directory
Cross-reference heat number	Ask the mill to confirm heat number, order quantity, and delivery date against their records	Mill has no record of the heat number
Verify TPI signature (3.2)	Contact the TPI firm (Bureau Veritas, SGS, etc.) directly with certificate reference number	TPI firm has no record of the inspection event
Check chemical analysis plausibility	Compare actual values against specification limits; values that are suspiciously "perfect" or round may be fabricated	All values exactly at mid-range or specification limits
PMI (Positive Material Identification)	XRF or OES test on receipt; compare with certificate	Significant deviation from certificate chemistry
Check for inconsistency in formatting	Compare with known genuine certificates from same mill; look for font changes, altered date formats, copy artifacts	Visible editing artifacts; mismatched fonts
Request original hardcopy + digital copy	Digital copy can be emailed first; original should follow with shipment	Supplier refuses to provide original; only a photocopy available

Yes - if the purchaser's own authorized inspector signs as the second party (provided they meet the independence criteria defined in EN 10204 §3.2). For most commercial projects, however, a recognized third-party inspection agency (Bureau Veritas, SGS, TÜV, etc.) is used to satisfy both independence and regulatory acceptance requirements.

Q2: My supplier says they can issue a 3.2 certificate themselves with two internal signatories. Is this valid?

No. This is a common misconception and a regulatory red flag. EN 10204 §3.2 explicitly requires the second signatory to be either (a) the purchaser's authorized representative or (b) an inspector designated by official regulations. A second signature from another manufacturer's employee - regardless of their department - does NOT constitute a valid 3.2 certificate. Insist on a genuinely independent external party.

Q3: Does EN 10204 apply to materials manufactured outside Europe?

Yes - EN 10204 is widely adopted globally. ASTM A-Series standards include a supplementary requirement (S1) that references EN 10204-equivalent certification. API, NACE, and major project specifications worldwide accept and require EN 10204 certificates regardless of the country of manufacture. A mill in South Korea, China, Japan, or the USA can and regularly does issue EN 10204-compliant certificates.

Q4: What is the difference between an MTR (Mill Test Report) and an EN 10204 certificate?

"MTR" and "Mill Test Report" are informal terms used in North America for what EN 10204 formally defines as a Type 3.1 Inspection Certificate. The content is equivalent: heat-specific chemical analysis and mechanical properties. When a project specification in North America refers to an "MTR," it generally means EN 10204 Type 3.1-equivalent documentation. If a 3.2-equivalent is needed, the PO should explicitly state "purchaser's representative witness" per ASME supplementary requirements.

Q5: How long should I keep EN 10204 certificates on file?

This depends on jurisdiction and industry. For pressure equipment under PED, certificates must be kept for at least 10 years (PED 2014/68/EU Article 11). For nuclear components, lifetime-of-plant retention is typically required. For offshore/marine class, the classification society retains copies; owners should keep them for the vessel's lifetime. A general industry rule of thumb is minimum 10 years for any safety-critical or pressure-containing component.

Q6: Can I request a 3.1 certificate to be "upgraded" to 3.2 after delivery?

No. A 3.2 certificate cannot be retroactively issued because the defining requirement - an independent third party witnessing the actual tests in real time - cannot be retrospectively fulfilled. If you receive 3.1 material when 3.2 was required, you have two options: (1) perform additional independent testing (PMI, mechanical re-testing) by a TPI and issue a supplementary inspection report (which may or may not satisfy your client or regulator), or (2) reject the material and require replacement with proper 3.2 documentation from the outset.

Q7: Is EN 10204 the same as ASTM A269 or ASME SA-312?

No. ASTM A269, ASTM A312, and ASME SA-312 are material specifications that define what alloy grades, dimensions, mechanical properties, and tests are required for stainless steel tubes and pipes. EN 10204 is a documentation standard that defines how the test results are certified. ASTM/ASME material standards reference EN 10204 (or its ASTM equivalent, supplementary requirement S1) as the format for issuing the certificate. You always need both: the correct material standard AND the correct certificate type.

JNAlloy is a manufacturer and distributor of stainless steel and nickel alloy products, serving oil & gas, chemical processing, marine, power generation, and pharmaceutical industries globally.

Capability	Details
EN 10204 Type 3.1	Standard issue - included with all material orders
EN 10204 Type 3.2	Available on request; approved TPI partners include Bureau Veritas, SGS, and Intertek
ITP (Inspection Test Plan)	Submitted to purchaser for approval on 3.2 orders minimum 10 working days prior to production
PMI Testing (XRF)	Available on request for any order; results documented in shipment package
Certificate language	English (standard); bilingual (English + Chinese) available on request
Certificate format	Electronic PDF + original hardcopy accompanies shipment
Traceability	Full heat-to-shipment traceability maintained; heat numbers marked on all items
Grades covered	SS 304/316L/321/347/310S/904L/2205/2507; Nickel alloys 200/201, Inconel 625/825, Hastelloy C-276, Monel 400
Third-party verification	Certificate reference numbers can be independently verified via TPI firm portals