Welder Certification (EN ISO 9606): What It Is and How to Get It
In pressure vessel, steel structure or pipeline fabrication, work is not accepted without a certified welder. How the EN ISO 9606 test works, what the certificate covers, how long it is valid, and why welder certification differs from procedure qualification (WPQR).
Welder certification is the proof, through an independent test, that a welder can produce sound, standard-compliant welds under defined conditions. In pressure equipment (PED), steel structures (EN 1090), pipelines and boiler fabrication, a valid welder certificate is indispensable — work produced by an uncertified welder is rejected in audits and by customers.
The most common standard for steel materials is EN ISO 9606-1. (Aluminium is covered by 9606-2, and other materials by their respective parts. Welding operators — fully mechanised/automatic — fall under EN ISO 14732.)
How the test works
- Test weld to a WPS: The welder produces a test piece under an approved welding procedure specification (WPS), using a position, material and process that represent real production conditions.
- Examination: The test piece is assessed by visual examination plus the non-destructive testing (NDT) required by the standard (e.g. radiography) and/or destructive tests such as bend/fracture.
- Certificate: A welder who meets the acceptance criteria is issued a certificate stating the range of approval.
What does the certificate "cover"? — Range of approval
A single test qualifies not one condition but a range. For example, a test performed at a given diameter/thickness and position may cover a wider range of thicknesses and positions. The essential variables on the certificate (welding process, material group, product type — plate/pipe, position, filler metal, shielding gas) define which work can be done with it. Work outside these variables requires a new test.
How long is it valid?
EN ISO 9606-1 ties validity to continued working and periodic confirmation: the responsible welding coordinator confirms at defined intervals (typically every six months) that the welder continues to work within the certificate's scope. Under the conditions the standard permits, the certificate may be revalidated; otherwise re-testing is required.
⚠️ Exact validity periods and revalidation conditions can vary with the applied standard edition and the product/project specification. ASİS UK tracks your welders' certificate status and revalidation calendar for you.
Often confused: welder certificate ≠ WPQR
- Welder certificate (EN ISO 9606): qualifies the person — this welder can do this work.
- WPQR / pWPS (EN ISO 15614, etc.): qualifies the procedure — this welding method gives sound results on this material.
The two complement each other: the procedure is qualified first (WPQR), then the welder is certified to that procedure. Without both, the production file is incomplete.
With ASİS UK
ASİS UK carries out the inspection and testing part of welder certification (visual, NDT, destructive testing) in-house, while the certification itself is delivered with our accredited partner. Issued certificates are verifiable through our digital ecosystem. Our inspection (ISO 17020) activity is in the TÜRKAK accreditation process.
To certify your welders or plan revalidation of existing certificates, reach us through the Request a Quote form; our expert will respond within 24 hours.
— ASİS UK Certification Team