EN 10204 3.1 vs 3.2 Mill Test Certificates: What International Steel Buyers Need to Know

EN 10204 is about who validates the results, not what gets tested

EN 10204 (Metallic products — types of inspection documents) doesn't define the chemical or mechanical requirements a plate has to meet — that comes from the product standard, which for shipbuilding steel is the classification societies' own IACS UR W11. What EN 10204 governs is who is authorized to certify, in writing, that a specific shipment's test results meet those requirements.

3.1: validated by the mill's own quality department

A 3.1 certificate is issued and validated by the manufacturer's own authorized quality department — organisationally independent of the production department, but still inside the same company. It reports the actual chemical composition and mechanical test results for the heat the plate was rolled from. This is the default document type for the large majority of commercial shipbuilding steel shipments, and it's what a mill test certificate means unless a contract states otherwise.

3.2: the same report, plus an independent countersignature

A 3.2 certificate carries the same test data as a 3.1, plus a countersignature from a party independent of the manufacturer's own department — in shipbuilding steel, typically the classification society surveyor assigned to witness the relevant test or sampling. The extra signature is what changes. A 3.2 certificate isn't reporting different or better steel; it's the same results, confirmed a second time by an independent party.

When buyers actually need 3.2

Classification-society oversight of the mill is already continuous, not occasional: the WISCO mill holds works approval from nine classification societies — CCS, ABS, DNV, GL, BV, LR, RINA, KR and NK — simultaneously. A buyer typically needs a 3.2 certificate specifically when their own contract, their classification society's rules for that particular newbuild, or their end customer's specification calls for third-party witnessed inspection in writing — not as a general trust upgrade over 3.1. If nothing in your own contract requires it, 3.1 is the standard, faster route, and it isn't a lesser document.

What changes operationally if you request 3.2

SGS, BV or your own surveyor can witness sampling if requested at order stage. That timing matters: the countersigning surveyor has to actually attend the original test, so a 3.2 certificate can't be requested after the plate has already shipped — it has to be built into the purchase order before the heat is rolled and tested. Confirm the requirement against your own contract or classification society rule, not assumption, before adding it to an enquiry.