EN ISO 3834 explained for buyers
What does a supplier certified to EN ISO 3834 guarantee? The levels of the standard, what it requires of the workshop, its link with EN 1090, and when to require it in your purchasing.
You buy welded parts and a supplier highlights its EN ISO 3834 certification. What exactly does that guarantee you? And should you require it? Here are the essentials, without unnecessary jargon.
A quality standard specific to welding
The EN ISO 3834 series defines quality requirements for fusion welding of metallic materials. Whereas a management standard such as ISO 9001 looks at the organisation in general, EN ISO 3834 focuses on what makes a weld good: people, procedures, equipment, inspection.
A weld has a particular feature: its quality cannot be fully verified afterwards without destructive testing. It is known as a special process. The only way to guarantee the result is to control the process itself. That is exactly what the standard is about.
The parts of the standard
| Part | Content |
|---|---|
| EN ISO 3834-1 | Criteria for selecting the appropriate level of requirements |
| EN ISO 3834-2 | Comprehensive quality requirements |
| EN ISO 3834-3 | Standard quality requirements |
| EN ISO 3834-4 | Elementary quality requirements |
| EN ISO 3834-5 | Documents to comply with to claim conformity with parts 2 to 4 |
| EN ISO 3834-6 | Guidelines for implementation |
The level is chosen according to how critical the parts are: a highly stressed structure or one subject to fatigue justifies comprehensive requirements; a lightly loaded part may need only elementary requirements.
What the standard requires of the workshop
A workshop complying with EN ISO 3834 must control, in particular:
- Review of requirements and technical review: before manufacturing, it checks that it has understood your requirements and can meet them (materials, processes, inspection, tolerances).
- Personnel: welders qualified to EN ISO 9606-1, automatic welding operators to EN ISO 14732, and a welding coordinator with competences defined by EN ISO 14731.
- Procedures: welding procedure specifications (WPS), qualified by tests to EN ISO 15614-1 for steels.
- Equipment: suitable, maintained and validated where necessary.
- Materials: compliant parent and filler materials, stored correctly.
- Inspection: before, during and after welding, according to a defined plan.
- Non-conformities: how they are handled and the corrective actions.
- Identification and traceability, and quality records.
What it guarantees you, in practice
As a buyer, a supplier certified to EN ISO 3834 assures you that:
- your requirements are reviewed before manufacture, not discovered on delivery;
- welds are made by qualified people, following qualified procedures;
- inspections are planned and recorded;
- a non-conformity is handled according to a procedure, not case by case.
What the standard does not guarantee: that a poorly designed part becomes a good one. The supplier welds what is drawn; the design remains your responsibility, hence the value of an early dialogue (see our STEP preparation guide).
The link with EN 1090
For structural steel components placed on the European market (frames, walkways, structural guardrails, etc.), CE marking to EN 1090-1 is mandatory. And EN 1090-2 requires conformity with EN ISO 3834, at a level that depends on the execution class (EXC1 to EXC4). If your parts are structural components, EN 1090 is therefore the first thing to look at.
Should you require it?
- Yes, for parts subject to heavy loads, fatigue, or whose failure would have serious consequences.
- Yes, if your own customers or your CE marking require it.
- Not necessarily, for lightly stressed parts: a supplier that applies the standard without being certified, or targeted contractual requirements (welder qualification, documented visual inspection), may be enough. Requiring too high a level makes the part more expensive without any benefit.
And at Newstack Robotics?
Our welding procedures are established to EN ISO 3834; certification is targeted as production starts. We present it as such, without anticipating it. Our technical capabilities page states where we are, and our safety and standards page presents all the standards that frame our cell.
Key takeaways
EN ISO 3834 guarantees that a workshop controls its welding process: requirements reviewed, qualified personnel and procedures, planned inspections, non-conformities handled. It is a real sign of reliability for a buyer, to be required at the right level depending on how critical your parts are.