EN 10204 3.1 vs 3.2: Which Certificate to Order

Karachi’s water utility wrote its certificate requirement into a World Bank–funded specification as one line: “Manufacturer’s Work Test Certificate for all material used shall be furnished by the contractor for Project Manager’s scrutiny and approval.” No type number, no EN 10204 reference, no clause about who signs it. The supplier still has to decide what to issue — and the gap between the cheapest document that satisfies that sentence and the one the engineer assumes he ordered is where deliveries stall.

In about five minutes you will know which of the four EN 10204 document types to name in your purchase order — and you will be able to write the requirement into the PO so the paperwork arrives with the goods, not three weeks after them.

Before the detail:

• Commercial parts, no load path, no pressure boundary → type 2.2.
• Structural, mechanical or pressure-piping fasteners with a rated property class → type 3.1, heat-traceable, with measured values.
• Sour service, offshore, nuclear, higher PED categories, or any buyer who sends an inspector → type 3.2.

Why the type decides your risk

1. EN 10204 does not say what to test. It says who may sign and whether the test covers your lot — is the testing specific to the material delivered to me, and is anyone independent of the maker involved.
2. Real tenders enforce the principle before they use the vocabulary. On the KWSSIP water project in Karachi, §1.4.7 makes a Manufacturer’s Work Test Certificate mandatory for all materials — a type 3.1 expectation written by a buyer who never mentions EN 10204.
3. The same document also hands the engineer discretion. At §1.7.2 it states that “the Project Manager may accept the manufacturer’s certified mill and laboratory certificate”. “May”, not “shall”. If the type is not nailed down in your offer, the decision moves to a reviewer you will never meet.
4. For fasteners, “conforms to ISO 898-1” is not a measurement. Grade 6.8 has a nominal and minimum tensile strength of 600 MPa; grade 10.9 is nominal 1,000 MPa and minimum 1,040 MPa — the minimum sits above the nominal. A certificate that only says “10.9, conforms” hides which number the steel reached.

The four types in one table

EN 10204:2004 replaced DIN 50049 in Europe; its ISO counterpart for steel products is ISO 10474:2013. The framework has four document types, and the comparison turns on three columns.

Type	Document name	Issued by	Testing basis	Heat / lot traceability	Independent witness
2.1	Declaration of compliance	Manufacturer	No test specific to the order	No	No
2.2	Test report	Manufacturer	Non-specific — production data for the same product, not your lot	Not guaranteed	No
3.1	Inspection certificate 3.1	Manufacturer’s authorized inspection representative, independent of the production department	Specific to the delivered lot	Yes	No
3.2	Inspection certificate 3.2	Manufacturer’s authorized representative plus the buyer’s representative or an appointed third party	Specific to the delivered lot, witnessed	Yes	Yes

Type 2.1 is the one buyers most often forget: it carries no test data, and it is routinely offered where 2.2 was expected. The type is set by the order, not by the mill’s default — if the PO says “mill certificate”, the seller may legitimately issue 2.1, because that phrase is not a defined type. And EN 10204 covers the inspection document, not service approval: a 3.1 certificate does not make a gasket drinking-water safe, which is a separate product approval as in flange gasket certification for potable water.

2.2 vs 3.1 vs 3.2, type by type

Type 2.2: a report about production, not about your lot

A 2.2 test report is issued against production data — typically results from the same grade and process, not from the heat that became your bolts. It carries values, which is why it is often mistaken for more than it is. What it lacks is a traceable link between the tested material and the material in your crate.

Use it for commercial-grade hardware with no specified property class, no designed load path and no pressure boundary; cost and lead time are unaffected.

Type 3.1: your lot, tested, signed inside the works

A 3.1 inspection certificate is issued against the specific lot delivered, and the signature must come from an authorized inspection representative independent of the department that produced the material. That independence is the point: the person who ran the heat-treatment furnace does not sign off their own work.

For fasteners this is the default procurement gate — general mechanical and structural work, OEM parts outside safety-critical use, pressure-piping bolts, and any order where the customer’s quality system needs batch evidence. Expect roughly one to two weeks added to lead time, since the tests must run against the heat actually being shipped rather than be copied from an earlier report.

Type 3.2: the same certificate, witnessed from outside

Type 3.2 adds a second signature: the buyer’s representative, or an independent inspection body acting for the buyer, witnesses the testing and countersigns. The content is otherwise the 3.1 content; what changes is that the party who pays for the goods has had eyes on the testing.

That is what “third-party inspection required” means in a tender: it is not a synonym for 3.1, and a mill cannot produce it from its own quality department. Sour service, subsea and offshore work, nuclear, and higher PED categories are the classic triggers. Budget roughly two to four more weeks on top of normal lead time.

The mistake to avoid is treating 3.1 as if it were already independent. The 3.1 signatory is independent inside the works; the signature still belongs to the manufacturer. If your specification says “third-party inspection”, ask for 3.2 by name.

What a 3.1 must show for fasteners

A certificate that says a batch “conforms to ISO 898-1” has told you nothing you can check. For a fastener order it has to carry measured values you can compare against the grade you paid for. The figures below come from ISO 898-1 and its Chinese counterpart GB/T 3098.1-2010 — the same property system in a free public standard, useful when you want a citable table.

Property	6.8	8.8 (d ≤ 16 mm)	10.9	12.9
Tensile strength Rm, nominal (MPa)	600	800	1,000	1,200
Tensile strength Rm, minimum (MPa)	600	800	1,040	1,220
Yield property measured	RPf (0.0048d)	RP0.2	RP0.2	RP0.2
Yield, nominal (MPa)	480	640	900	1,080
Yield, minimum (MPa)	480	640	940	1,100
Elongation after fracture, min	not specified — Af ≥ 0.20 on the fastener	12%	9%	8%
Hardness (HV)	190–250	250–320	320–380	385–435

Read the first two rows together, because that is where certificate arguments start. The grade number is a labelling convention: the digit before the point, times 100, gives the nominal tensile strength, and the digit after the point gives the yield-to-tensile ratio. It does not give the minimum. For 8.8 the two coincide at 800 MPa; for 10.9 and 12.9 the minimum is higher than the nominal. A supplier reading 1,020 MPa off a test report for grade 10.9 has produced a genuine test value and still failed the grade.

Two more fields belong on the same document:

• Heat number, and a match to the physical marking. One certificate covering several heats is normal and legitimate, but it must list every heat, and the marking on the parts or packaging must let you match the crate to the certificate line. A certificate whose heat number appears nowhere on the goods is unverifiable however good the numbers look.
• Coating values, measured — not a coating process name. “Hot-dip galvanized” is a process description; the acceptance criterion is a thickness in micrometres. ASTM F2329 sets the minimum coating on threaded fasteners in three tiers, not one, and a single averaged figure is not the requirement:

Thread size	Production-lot average	Lot-inspection average	Single-specimen average
Over 3/8 in [M10]	50 μm	43 μm	43 μm
3/8 in [M10] and under	43 μm	38 μm	38 μm

F2329 measures with ASTM E376 (magnetic / eddy-current, for the shop floor) and ASTM B487 (metallographic cross-section, as the referee method). Those two method numbers tell you more than the word “galvanized” ever will. One conflict is worth a written question: grade 12.9 requires 385–435 HV, roughly the 39–44 HRC band (hardness conversions are approximate), and ASTM F2329 prohibits hot-dip galvanizing threaded fasteners that reach 40 HRC or are made of carburized steel. A 12.9 bolt offered “hot-dip galvanized to F2329” is a technical contradiction.

Two real tender clauses

Here are the two clauses this article started from, quoted as short transcriptions with clause numbers and the public source document. They pull in opposite directions.

Clause 1 — the mandatory certificate. Vol-II Specifications, §1.4.7 “Structural Steel Works”, inspection and tests, PDF p.134:

“Manufacturer’s Work Test Certificate for all material used shall be furnished by the contractor for Project Manager’s scrutiny and approval.”

Source: KWSSIP Request for Bids — Plant, Contract Package G-1 (RFB PK-KWSB-325427-GO-RFB), Vol-II Specifications §1.4.7 (p.134), Karachi Water and Sewerage Services Improvement Project, World Bank loan IBRD 8994-PK — public document.

“Manufacturer’s Work Test Certificate” is a document EN 10204 does not define — the buyer’s own term for a works-issued certificate carrying the maker’s test results, in practice the 3.1 role. Note what the buyer did not write: no heat traceability, no independent signatory, no list of values. A supplier answering the clause literally can be compliant and still deliver something the Project Manager refuses.

Clause 2 — the discretion. The same document, §1.7.2 “Civil Works”, under the tests heading, sub-items (ii) Mill Certificate and (iii) Testing Laboratory Certificates, PDF p.169:

“The Project Manager may accept the manufacturer’s certified mill and laboratory certificate.”

Source: same document, §1.7.2 (p.169) — public document.

“May accept” is permission, not entitlement, and it leaves the decision with the individual who also holds the approval right under clause 1. The same page puts the cost of re-testing after a failed submission on the contractor. Put those provisions together and the commercial logic is clear: a certificate the Project Manager can accept without discussion is worth more than the cheapest document the wording allows, because the alternative is a re-test at your cost and a delay you cannot bill to anyone.

Neither clause says “EN 10204” — common in World Bank and utility tenders, where the requirement is real and the vocabulary is local. Which is why “which type?” has to be answered by you in the order, not inferred from the tender.

Writing the certificate into your RFQ

The certificate becomes enforceable the moment it stops being an assumption and becomes an order line. Four things make it a delivery condition.

1. Name the type and the traceability. Keep it to one line, so the seller cannot interpret it:

Material to be supplied with EN 10204 Type 3.1 inspection certificate, heat-traceable to the delivered lot.

For risk-critical orders:

Independent third-party inspection (TPI) witnessing required; EN 10204 Type 3.2 inspection certificate.

2. State the minimum content, not just the type. Add the values you will check: measured tensile and yield, elongation and hardness for the ordered property class, heat number matching the marking, and coating thickness with its measurement method. That is the difference between receiving a certificate and receiving a document you can accept.

3. Make it a deliverable with a date. List the certificate among the delivery documents rather than under quality notes, and give it a submission deadline — with the goods, or at least before release for shipment. A certificate requested after the containers are loaded is a negotiating position, not a requirement. This is our own practice from sourcing fastener orders, not a quotation from a standard.

4. Do not over-specify by reflex. Type 3.2 on a box of non-structural washers buys a certificate nobody will read and pays for two witnesses. Match the type to the consequence of failure.

Three decisions that settle it

• The type is about your lot and your signatory, not the mill’s reputation — 3.1 is specific to the material delivered and signed by an inspection function independent of production; 2.2 is on the process, not on your goods.
• Nominal and minimum are different numbers, and only one is the acceptance limit — 10.9 is 1,000 MPa nominal and 1,040 MPa minimum, so a certificate must state which figure its values are compared against.
• “May accept” wording puts the risk back on you — where a specification allows buyer discretion and charges re-tests to the supplier, the cheapest compliant document is the most expensive choice.

Before you release the PO

Check your 3.1 line by line

This article is about the type; the next step for a QC team is the arithmetic of accepting one. That is what our fastener receiving inspection checklist is built for: a printable, clause-by-clause verification sheet for arriving documents, down to heat-number matching, value checking against the ordered grade, coating measurement and the tender clause behind each line. Yaxiio fits buyers who already have a specification and need the delivery to match it: send us the certificate with the property class and coating you ordered, and we will tell you which line fails and what to ask the supplier for — checked against the grade and coating on your order, not against a generic “conforms” statement. The structural fastener range is a fair picture of the grades and coatings that arrive with which document type. For context, see how to read an MTC and the wider seven reports buyers should request.

References

• EN 10204:2004 — Metallic products — Types of inspection documents. European Committee for Standardization (CEN); replaced DIN 50049 in 2004. Four document types: 2.1, 2.2, 3.1, 3.2.
• ISO 10474:2013 — Steel and steel products — Inspection documents
• ISO 898-1:2013 — Mechanical properties of fasteners made of carbon steel and alloy steel — Part 1: Bolts, screws and studs
• GB/T 3098.1-2010 — Mechanical properties of fasteners: bolts, screws and studs — Table 3 (free public standard, same property system as ISO 898-1)
• ASTM F2329 — Standard Specification for Zinc Coating, Hot-Dip, Requirements for Application to Carbon and Alloy Steel Bolts, Screws, Washers, Nuts, and Special Threaded Fasteners (coating thickness tiers; measurement by ASTM E376 and ASTM B487)
• KWSSIP Request for Bids — Plant, Vol-II Specifications, §1.4.7 (p.134) and §1.7.2 (p.169), Contract Package G-1, RFB PK-KWSB-325427-GO-RFB
• World Bank Project P171422 — Karachi Water and Sewerage Services Improvement Project