Welder Certification (ISO 9606)
Concepts and Certification Process
In the fields of pressure vessel, steel structure, or piping fabrication, work cannot be accepted without certified welders. This article explains the testing process under the EN ISO 9606 standard, the scope of the certificate, its validity period, and the distinction between welder certification and the approved welding procedure (WPQR).
Welder Certification (ISO 9606)
A welder certificate serves as confirmation—verified through an independent test—that a welder is capable of producing quality welds in compliance with standards under specific conditions. In sectors such as pressure equipment (PED) manufacturing, steel structures (EN 1090), piping, and boilers, holding a valid welder certificate is mandatory; work performed by uncertified welders will be rejected during inspections and by clients.
Test Execution Process
Welding the test coupon according to an approved Welding Procedure Specification (WPS):
• The welder produces a test coupon following an approved WPS, utilizing welding positions, materials, and methods that simulate actual production conditions.
Testing:
• The test coupon is evaluated through visual inspection combined with non-destructive testing (NDT) methods as prescribed by the standard (e.g., radiography) and/or destructive testing methods such as bend tests or fracture tests.
Certification:
• Welders who pass the test are issued a certificate specifying their scope of qualification.
What does the certificate cover? — Scope of Approval
A single test validates not only a specific condition but also a range of conditions. For example, a test conducted with specific diameter/thickness and position parameters may cover a broader range of thicknesses and positions. The essential variables recorded on the certificate (welding process, material group, product type—plate/pipe, welding position, filler metal, shielding gas) define the scope of work permitted under that certification. Work falling outside the scope of these variables requires a new test.
What is the validity period?
The EN ISO 9606-1 standard ties the certificate’s validity to continued work activity and a periodic confirmation process: the responsible welding coordinator must confirm at specified intervals (usually every six months) that the welder is still performing work within the certified scope.
If the conditions permitted by the standard are met, the certificate’s validity can be extended; otherwise, the welder must retake the test.
Interlink Vietnam’s Services:
Advising clients on relevant technical regulations, standards, and procedures for ISO 9606 certification.
Guiding clients through the preparation and submission of relevant documentation to the certification body to obtain ISO 9606 certification in the simplest and most efficient manner.
