What an EN 10204 3.1 mill test certificate tells you
A 3.1 certificate links your fittings to a heat of steel. See what it contains, how it differs from 2.2 and 3.2, and how to check one before accepting material.
Fortune Technical Desk4 min readOn this page
Test certificates are the paper trail behind every pressure-retaining part. Buyers often ask for them, but fewer people read them. This article explains what an EN 10204 3.1 certificate tells you and how to check one properly.
What EN 10204 is
EN 10204 is a European standard that defines the types of inspection documents that a manufacturer can issue for metallic products. It is used across the world, including in India, to describe how the test results were produced and who verified them. The standard itself does not set test requirements. Those come from the product specification, such as ASTM A234 or A403.
The document types
For most industrial piping a 3.1 certificate is the standard requirement. Where a code, owner or regulation demands it, a 3.2 certificate is used, with an independent surveyor or the client representative co-signing.
What a 3.1 certificate contains
The exact format varies, but a proper certificate normally includes the following.
- Manufacturer name and certificate number
- Purchaser, order number and product description
- Material specification and grade, for example ASTM A403 WP316L
- Heat number and, where relevant, lot or batch number
- Chemical composition from the heat analysis, with product analysis if required
- Mechanical properties: yield strength, tensile strength and elongation
- Heat treatment condition, such as solution annealed or normalised
- Results of additional tests such as hardness, impact, hydrostatic or non-destructive tests where specified
- Signature or stamp of the authorised inspection representative
How to check one
Step 1: tie it to the material
Compare the heat number on the certificate with the markings on the fittings. If the heat numbers do not match, the certificate is not valid for that material.
Step 2: check the grade and standard
The grade and the standard on the certificate must be the ones on your order, including the right edition if the order specifies one. A WP304 certificate does not prove a WP316L fitting.
Step 3: check the numbers against the specification
Look up the chemical limits and minimum mechanical properties in the product specification and confirm every reported value is inside them. Pay attention to carbon content on L grades and to molybdenum on 316 grades, and to yield and tensile strength against the minimums.
Step 4: check the signature and traceability
The certificate should be signed or stamped, dated and traceable to the manufacturer. Be careful of altered or photocopied documents with edited values.
Handling certificates in a project
Keep the certificates with the heat numbers recorded on spool drawings, so each spool, fitting and flange can be traced back through the fabrication records. Digital copies stored with the material receiving report save a lot of time at final documentation and audit stages.
Planning an order that needs documentation? Ask us for test certificates when you request a quote and tell us whether you need 3.1 or 3.2.
Send us your list and we will reply with a quote.
Request a QuoteFrequently asked questions
Is a 3.1 certificate the same as a mill test certificate?
In everyday use, yes. A mill test certificate or MTC normally means a 3.1 certificate that lists the heat and test results. Strictly, the certificate may be issued by the fitting manufacturer on the basis of the mill results.
When do I need 3.2?
When the project specification, a regulation or the owner asks for third-party or purchaser witnessing of tests. It costs more and takes longer, so specify it only when required.
Does a certificate replace inspection on receipt?
No. It documents the manufacturer results. You still need to check markings, dimensions, surface condition and, for critical lines, PMI.
