EN ISO 9606-1 is the European standard that governs the testing and certification of welders for fusion welding of steel. For the client, a certificate to this standard is the most reliable proof that a weld will be made professionally, repeatably and in line with the project requirements. Below we explain what the certificate actually covers and how to check whether it is valid.
What EN ISO 9606-1 is
The standard verifies the practical competence of the welder — not the company, but the specific person. The welder makes a test weld, which is examined by an authorised body (visually, radiographically or by other methods). If the weld conforms, the welder receives a certificate stating the precise range of validity.
It is important to understand: the certificate is not valid “in general”. It is valid for a precisely defined combination of conditions under which the welder was tested.
What the certificate covers (range of validity)
Every EN ISO 9606-1 certificate states:
- The welding process (e.g. 111 MMA, 135/136 MAG, 141 TIG)
- The product type — plate or pipe, and the thickness range
- The base material group and the filler material
- The welding position (PA, PF, PC …)
- Joint details (butt/fillet, with or without backing)
Validity and renewal
The certificate is time-limited. It remains valid if the employer confirms every six months that the welder works within the certified conditions; otherwise it lapses. A longer renewal (usually to two or three years) requires additional testing or examination of production welds.
That is why, with a contractor, it makes sense to check not only that a certificate exists, but also that it is still valid on the day the work is carried out.
How the client verifies competence
Before work begins, request copies of the certificates of the welders who will work on the project, and check that the range of validity matches your welds (material, thickness, position, process). For more demanding structures, welder certificates are linked to a welding procedure specification (WPS), which describes how the weld must be made.
Orderly documentation is not bureaucracy — it is insurance against defects, delays and additional repair costs.
Why this matters
An incorrect or inadequately certified weld can mean rejection at acceptance, re-doing the work and delaying the whole project. With load-bearing steel structures, bridge building or the energy sector, safety is also at stake.
At Save Consulting we provide welders with valid EN ISO 9606-1 certificates for processes 111, 135/136, 141 and SAW, with proper documentation for every project.