EXC3 bridge contract: qualification gaps in a certified fabricator
A structural steel fabricator is certified to ISO 3834-3 and has an EN 1090-2 factory production control certificate for execution class EXC2. It wins a contract for a road bridge requiring EXC3. The project specifies EN 1090-2, WPS to ISO 15614-1, welders to EN ISO 9606-1, and a welding coordinator. The fabricator plans to use its existing WPS qualified on a 10 mm butt test piece for 25 mm full-penetration butt welds, and its welders qualified on 12 mm plate for the same joints. It also plans to subcontract 30% of the welding to a workshop with ISO 3834-3. The client's auditor finds no welding coordinator with IWE/IWT qualification and no impact-testing of the WPS. The fabricator argues that its ISO 3834-3 certificate is sufficient because the weld is not 'high risk'.
1. Assess the gaps between the fabricator's qualification and the EXC3 contract.
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Gaps:
- EXC3 normally requires a welding coordinator and a quality system consistent with ISO 3834-2, not 3834-3;
- the 10 mm PQR does not cover 25 mm; the ISO 15614-1 range for a 10 mm butt test is about 5–20 mm;
- impact testing is required by the project and is not covered;
- welder qualification on 12 mm may not cover 25 mm full penetration; check the EN ISO 9606-1 range and joint details;
- the subcontractor with 3834-3 is not automatically acceptable for EXC3;
- the FPC certificate is for EXC2, not EXC3.
2. What is the minimum acceptable route to close each gap before production?
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Minimum route:
- appoint an IWE/IWT welding coordinator;
- produce a project-specific PQR on 25 mm with impact tests;
- derive WPS within the qualified range;
- qualify or extend welders to 25 mm;
- revise the FPC and inspection/test plan for EXC3;
- obtain client approval for the subcontractor or use a 3834-2 workshop.
Do not start production until the PQR and WPS are accepted.
3. How would you handle the subcontractor's ISO 3834-3 certificate?
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Treat the 3834-3 certificate as evidence of a partial system, not equivalence. Perform a subcontractor assessment covering welding coordination, WPS/PQR, welders, equipment, NDT, traceability and calibration. Require project-specific WPS/PQR and welder qualifications for the 25 mm joints. The main fabricator remains responsible. If the subcontractor cannot meet EXC3, move the work or seek a client concession with technical justification.