EN 10204 3.1 vs 3.2: which material certificate a marine part actually needs

A material certificate is not paperwork you file and forget - it is the difference between a part you can install under class and a part you cannot. Most disputes come down to one line: was it a 3.1 or a 3.2, and did anyone actually check. Here is what each grade means and where the line sits for marine parts.

The four grades, in plain terms

EN 10204 defines four certificate types in two families. The 2.x family is non-specific inspection - the results describe the manufacturer's general production, not your batch. The 3.x family is specific inspection - the tests were run on the actual material you are getting.

• 2.1 - declaration of compliance. The maker states the product meets the order. No test results at all.
• 2.2 - test report. The maker gives test figures, but from general production, not necessarily your lot.
• 3.1 - inspection certificate. Test results from your actual batch, signed off by the maker's inspection representative who is independent of the production department.
• 3.2 - inspection certificate, countersigned. The same batch-specific testing as 3.1, but validated by a second, independent party as well - your representative or an inspector named by the rules, usually a class surveyor.

3.1 vs 3.2 is about who witnesses, not what is tested

This is the point that gets muddled. A 3.1 and a 3.2 can describe identical tests on identical material. The difference is the signature: on a 3.1 the manufacturer validates its own result through an independent internal function; on a 3.2 an outside party countersigns. So 3.2 is not a better material, it is an independently witnessed one. You ask for 3.2 when the item is critical enough that class wants its own eyes on the test, not when you simply want higher quality.

Where the line sits for marine parts

• General and non-critical material - non-structural fasteners, low-duty fittings - 2.1 or 2.2 is normal.
• Pressure-bearing and critical parts - valve and pump bodies, shafts, connecting rods, high-pressure fuel components - 3.1 is the practical floor.
• Class-surveyed and safety-critical items - where the survey scope calls for an independent witness - 3.2, or a class certificate that carries the same weight.

EN 10204 itself does not tell you which grade a given part needs. That comes from the class rules and your own specification. The trap is assuming a 3.1 will pass where the survey scope quietly required a 3.2 - you find out at installation, with the part already at the ship.

What to check before the part ships

• The certificate is specific: it names the heat or batch number, and that number matches the stamp on the part.
• The grade matches what class actually requires for that item, not what was cheapest to issue.
• For 3.2, the independent party is genuinely independent and named - a countersignature from the same maker is not a 3.2.
• The document travels with the part, not to follow with the invoice.

How this works with us

Every quote states the certificate grade that comes with the part, and for critical items we quote to the grade your class scope needs rather than the cheapest one available. Where a 3.2 or a class certificate is required, we arrange the witness before dispatch and send the documents for your approval first - so nothing arrives at the ship that cannot be signed off.