A welding quality certificate is only useful if it matches your project. Before you award structural steel work, verify seven things: the legal name, the site, the standard, the scope, the validity dates, the annex and the welding coordinators. Each check takes a few minutes, and together they show whether the certificate applies to the members you are buying.
1. The legal name
The name on the welding quality certificate should match the company that signs your contract. A certificate held by a parent company, a trading partner or a subcontractor does not automatically cover the supplier you are dealing with.
2. The site where the work is done
Certificates usually name two places: the head office and the operative site. The operative site is where the welding takes place. Check that it is the plant that will make your members. Head office addresses can change after a certificate is issued, so a difference there is worth a question, but the operative site is the important one.
3. The standard and the part
Look for the full reference, for example EN ISO 3834-2:2021. The part number tells you the level: Part 2 is comprehensive, Part 3 standard and Part 4 elementary. Compare it with what your specification requires. Our explanation of EN ISO 3834-2 welding certification describes what the comprehensive level covers.
4. The scope of supply
The scope states what the certificate applies to. In our case it reads manufacture and installation of structural steel components and accessories for civil, industrial and infrastructure works. If your project is outside the stated scope, the certificate may not help you.
5. The validity dates
Read the initial certification date, the issue date and the expiry date. A certificate normally depends on continued satisfactory operation and annual re-evaluation. Ask when the last review took place.
6. The annex
The annex is where the detail is. It lists the parent material groups, the welding processes and the welding coordinators. Match them with your job:
- Is your steel grade inside the listed material groups?
- Is your welding process on the list?
- Are the coordinators named with a competence level?
7. The welding coordinators
ISO 14731 describes the tasks and the competence of welding coordination. The annex lists each coordinator and a level. Ask who coordinates your project and whether that person is on the list.
A worked example
The certificate held by Truong Thinh is number INY-CER/26/1220 Rev.00, issued by Bureau Veritas Vietnam on 28 September 2026 and valid until 16 September 2029. The annex lists parent material groups 1.1 and 1.2, welding processes 136 and 121 and three welding coordinators assessed against ISO 14731:2019. The full certificate and annex are on our certified quality page. For the supplier questions that go with it, see our guide to how to choose a steel structure manufacturer.
Verify the welding quality certificate with the issuer
Whatever the paper says, the issuing body is the final check. Our certificate states that its validity can be confirmed with Bureau Veritas Vietnam on +84 28 38 122 196. For general background, see this overview of welding processes, and for material evidence on the steel itself read our guide to mill test certificates.
If you would like to review our certificate against your project specification, contact the engineering team and we will walk through the annex with you.
Frequently Asked Questions
What should I ask for besides the certificate?
Ask for the welding procedure specifications, the welder qualification records and the inspection plan for your project. They show how the certified system applies to your members.
Does a certificate prove that every weld is sound?
No. It shows that welding is controlled and recorded. Weld quality is confirmed by inspection and testing under your project specification.
What if the head office address on the certificate is old?
Ask the supplier to confirm the change in writing. The operative site named on the certificate is the address that matters for where the work is done.
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