Can my subcontractor work under my EN 1090 and ISO 3834 certification?

Posted on: 21/04/2026

Category: Product Certification

The short answer is Yes but with conditions. A company holding EN 1090 certification (Factory Production Control) and ISO 3834 can subcontract work and allow a subcontractor to operate under its system, provided the certified company retains full responsibility and control over the work. However, the subcontractor cannot simply “use” the certification independently.

  1. ISO 3834 rules on subcontracting

ISO 3834 explicitly allows subcontracting of welding or related processes (e.g., welding, NDT, heat treatment).

However:

  • The manufacturer remains responsible for the work. 
  • The subcontractor must follow the manufacturer’s quality requirements and procedures. 
  • The manufacturer must provide the technical requirements and documentation and ensure the subcontractor complies with them.

In other words, subcontractors do not need their own ISO 3834 certificate, but they must operate within the certified company’s quality system and be controlled by it.

2. EN 1090 responsibilities of the certified manufacturer

Under EN 1090-1, the certified manufacturer must maintain a FPC system covering all production activities, including traceability, inspections, welding control, and personnel qualifications.

Because of this: 

  • The certificate applies to the manufacturer’s controlled production system, not to other companies independently. 
  • Any outsourced activities must still be controlled through that FPC system.

Practically this means the certified company must ensure: 

  • subcontractor competence and approval 
  • welding procedures (WPS/WPQR) are used
  • qualified welders 
  • inspection and records integrated into the FPC system.

3. The key limitation (important legally)

A subcontractor cannot claim to be EN 1090 certified just because they work for a certified company. The certificate applies only to the certified manufacturer and its controlled processes.

Some examples:

Situation
Allowed?

Certified company subcontracts welding but controls it under its FPC

Allowed

Subcontractor works to certified company’s procedures

Allowed

Subcontractor markets itself as EN 1090 certified because of that work

Not allowed

Subcontractor manufactures and CE-marks products independently using the main contractor’s certificate

Not allowed

4. What auditors typically expect

During EN 1090 / ISO 3834 audits, certification bodies usually require: 

  • approved supplier/subcontractor list 
  • subcontractor evaluation records 
  • documented instructions to subcontractors 
  • traceability of materials and welds 
  • inspection/NDT records linked to the certified company’s FPC.

If these controls are missing, it often becomes a major non-conformity.

In Conclusion

A company with EN 1090 and ISO 3834 certification can subcontract work, but: 

  • the certified company must remain responsible, 
  • the work must be fully controlled within its FPC/ISO 3834 system, and 
  • the subcontractor cannot claim or use the certification independently.