ISO 3834 is a standard for the quality requirements of fusion welding, and a certificate shows that a fabricator controls its welding process as the standard requires. A TUV certificate shows that a third-party body assessed something, but you must read what, because the scope varies widely.
Neither one tells you that the weld in your machine is sound. They tell you how the maker is organised to produce welds.
What does ISO 3834 cover?
ISO 3834 is published in several parts. Part 2 sets comprehensive requirements, part 3 standard requirements, and part 4 elementary requirements. The level chosen depends on the product and the risk.
A fabricator certified to ISO 3834 has a defined system for these matters:
- Review of the contract and drawings before welding starts.
- Qualified welding procedures and qualified welders, usually to the ISO 15614 and ISO 9606 series.
- Control of welding consumables, equipment and inspection.
- A responsible welding coordinator with the right technical knowledge.
- Records that let a weld be traced back to who made it and how.
What does a TUV certificate show?
TUV is a family of German technical inspection and certification bodies. A certificate with a TUV logo could cover a management system, a product type, a welding qualification, or a one-off inspection. These are very different things.
When an Indian maker says it is "TUV certified", ask which body issued it, for which standard, for which product or process, and until when. A certificate for a quality system does not approve a particular machine.
How do you verify a welding certificate?
Ask for the certificate itself, with the certificate number, the issuing body and the scope. Check that the legal name and site match the factory you are buying from. Then confirm with the issuing body, or on its online register if it keeps one.
For structural or pressure work, ask for the welding procedure specifications and the welder qualification records for the actual job. A certificate is a starting point. The records show what happens on your order. What certifications an engineering supplier should have explains how this fits with other certificates.
Dates matter as well. Certificates of this kind are issued for a fixed period and are checked by surveillance audits. An expired certificate, or one that has been suspended, tells you the system is no longer being checked.
When do you need an independent inspector?
For high-risk or high-value items, a third-party inspector should witness testing and sign off before dispatch. Non-destructive testing, such as dye-penetrant, magnetic-particle, ultrasonic or radiographic checks, can be specified on critical welds.
Third-party inspection certificates covers what an inspector's report should contain. Add the inspection requirement to the purchase order, not as an afterthought.
Ask the fabricator for a welding procedure specification and a procedure qualification record for each joint type, and for the qualification certificates of the welders named on your job. Check that the welder's qualification range covers the material, thickness and position used. These are easy to ask for and quick to check, and gaps show up quickly.
Next step
We audit fabricators on the shop floor, check welding records and certificates, and arrange independent inspection where it is needed. To have a welding supplier checked, book a free sourcing review.