Traceability and marking for EN 1090: from steel to part

Traceability means that for every part in a structure, you can find which material, which weld and which check belong to it. Under EN 1090, this is not a luxury but part of your FPC system. Without traceability, you cannot determine which other parts are affected when a part is rejected.

Marking is the physical part: a number, label or stamp on the part that links it to your records. According to Bouwen met Staal (Building with Steel) , a notified body assesses your FPC system before you may apply the CE marking. Traceability is part of that system. The requirements themselves are in EN 1090-2, and you check them there.

Short answer: each part gets a unique number, which links to the material certificate, the WPS, the welder and the checks. Without that chain, you cannot prove your traceability.

What must you be able to find?

Imagine a steel beam structure with twenty parts. A crack appears in one beam. The question is then: which batch of steel was it, who welded it, with which WPS, and which checks were carried out? If you can answer that in fifteen minutes, your traceability is good.

The chain has four links:

Link	What you record	Where it is set out
Material	Batch or heat number and the 3.1 certificate	Material certificate 3.1
Process	WPS and welding method	WPS example
Person	Welder and their qualification	Welder certificate
Check	Hold points and records	ITP

What matters is the link between the links, not only the separate documents. A perfect certificate that is not linked to the part is of little value in practice.

Example: traceability record

The example below is fictional. It shows how you find one part of a column in your system. You use a unique part number that is stamped on the piece.

Part number	Material (heat)	Certificate	WPS	Welder	Check	Date
K-014-03	4471-A	3.1 no. 2026-0481	WPS-01 rev. 2	J. de Vries	ITP-05, visual OK	12 March 2026
K-014-04	4471-A	3.1 no. 2026-0481	WPS-01 rev. 2	M. Jansen	ITP-05, visual OK	12 March 2026
K-015-01	4472-B	3.1 no. 2026-0493	WPS-02	J. de Vries	ITP-06, NDT (non-destructive testing) OK	14 March 2026

With this table, you can find in one lookup which batch and which welder belong to a part. If heat 4471-A is rejected, you can use it to find all the parts that used that material.

How do you mark parts?

Mark parts in a way that the marking survives the whole process: from the workshop to assembly. A stamp is more durable than a sticker, and a label can disappear during painting. Choose the method that suits your material and your coating.

A marking always contains a unique number. Many companies also add the batch number. The exact content of the marking is set out in your FPC procedure, and that procedure is part of your certificate.

Choose the marking method

Choose a stamp, label or inscription, depending on the material and coating. Record the choice in your FPC.

Give each part a unique number

Link the number to the work order and the project file. Do not use numbers that could be duplicated between projects.

Apply the marking before the first operation

Mark the material before you saw or drill it. After sawing, the material is often no longer traceable to one batch.

Record the link

Note the part number next to the batch number, the certificate and the WPS. This is the record the auditor asks for.

Check the marking at final inspection

Check that the marking is still legible and matches the record. An illegible marking is a finding.

What does the auditor want to see?

The auditor picks a part and asks you to follow the chain. They go from the marking to the material certificate, to the WPS, to the welder and to the checks. If that cannot be done in a few minutes, the traceability is weak.

They also look at the separation between materials. If steel from two batches is stored together without marking, they cannot prove which batch was used where.

Common mistakes

Marking after sawing. A piece without a marking is hard to trace after sawing. Mark the material first.

Numbers that appear twice. Two parts with the same number in two projects make the records unusable.

Records in a separate system with no link. If the work order and the certificate do not refer to each other, the auditor has to work it out for themselves. That is a finding.

Marking that disappears under coating. Test the method with your coating. A label that peels off after galvanising helps nobody.

Frequently asked questions about traceability

Must I mark every piece of steel?

That depends on the execution class and on the requirements in the standard and the project specification. Ask your notified body which marking they expect, and record the choice in your FPC.

May I remove the marking after assembly?

That depends on the agreements. The marking often stays on the part, so it can be traced later. Discuss it with the client before you remove it.

How long must I keep the records?

Plan for at least ten years. Under Article 11 of the Construction Products Regulation (Bouwproductenverordening) , the manufacturer keeps the technical documentation and the declaration of performance for ten years after placing the product on the market. Agreements with the client may require a longer period.

What is the difference from the CE marking?

The CE marking is the label on the product that refers to the declaration of performance. The traceability marking is the internal link between a part and your records. They serve different purposes but are related. See the page on CE marking and DoP.