If you are planning a steel structure project — be it an industrial building, warehouse, bridge, or shopping center — at some point you will encounter the term EN 1090-2 Execution Class (EXC). This article explains what EXC classes are, how they differ, and how to choose the right level for your project.

What is EN 1090-2 and execution classes?

EN 1090-2 is the European harmonized standard governing the design, manufacture, and installation of steel structures. It has been mandatory in the EU since 2014. The standard defines four execution classes (EXC): EXC 1 (lowest), EXC 2 (medium), EXC 3 (high), EXC 4 (extreme cases). The class depends on importance, loads, and consequences of failure.

EXC 1 — light structures

Suitable for low-load facilities — fences, light canopies, small agricultural buildings. Rare in practice as most load-bearing structures need at least EXC 2.

EXC 2 — most ordinary buildings

The most common class. Suits offices, warehouses, smaller industrial buildings, apartment blocks, commercial centers. Material traceability, certified welders, welding engineer, and quality control plan are mandatory.

EXC 3 — high-responsibility structures

Required for structures whose failure could have serious consequences:

• Major bridges — road, rail, pedestrian
• Large industrial buildings
• High-rise buildings over 5 floors
• Energy facilities — substations, solar/wind parks
• Logistics centers

EXC 3 differs from EXC 2 in stricter requirements: NDT testing of all welds, full material traceability, IWE-qualified welding engineer mandatory, detailed documentation, additional production supervision.

Far fewer Estonian manufacturers hold EXC 3 than EXC 2 — it is a competitive advantage.

EXC 4 — extreme cases

Strictest class for structures whose failure could cause catastrophic consequences. Examples: nuclear facilities, large viaducts, airport structures, sports stadiums.

How to choose the right class?

EN 1090-2 defines three input criteria: Consequence Class (CC1-3), Service Category (SC1 static / SC2 fatigue), Production Category (PC1 or PC2). The combination determines the EXC. The class is normally selected by the structural designer — but the customer must verify the supplier holds the required certificate.

How to verify a supplier’s certificate?

1. Ask for the EN 1090-2 EC-Certificate and Welding Certificate (PDFs)
2. Check the certificates are valid (expiry date)
3. Verify the execution class the supplier may produce (e.g., “Up to EXC 3”)
4. Verify the certificate number in the issuer’s database (TÜV Eesti, TÜV NORD)
5. Ensure it covers the required material groups and welding processes

Steel Element and EN 1090-2 EXC 3

Steel Element OÜ and our production company ISM OÜ are certified to EN 1090-2:2018+A1:2024 EXC 3. We can take projects of all classes including high-responsibility bridges, large industrial buildings, high-rises, and energy facilities. We also hold ISO 9001:2015 (TÜV NORD), ISO 3834-2:2021 (TÜV Eesti), and a certified welding engineer (Pavel Kopanev, IWE).

All certificates are on our certificates page.

Planning a steel structure project?

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