EN 1090-2 Standard Explained: CE Marking, EXC1-EXC4 and Compliance

Since 1 July 2014, fabricated structural steel placed on the European market must carry CE marking under Regulation (EU) No 305/2011, the Construction Products Regulation (CPR). The conformity assessment scheme that applies to load-bearing steel components is defined in EN 1090-1, and the technical execution requirements those components must satisfy are set out in EN 1090-2. For a non-European fabricator exporting to the EU, that two-part framework matters twice: the certificate must cover both the component family and the execution class, and every piece of primary steel must be traceable to a conformity decision made inside the factory — not improvised on the site.

EN 1090-2:2018, “Execution of steel structures and aluminium structures — Part 2: Technical requirements for steel structures”, is an execution standard rather than a design standard. It governs how steel is prepared, welded, mechanically fastened, toleranced and documented once the design engineer has finished. Its central concept is the execution class (EXC): a four-level scale (EXC1 to EXC4) that scales fabrication controls, weld acceptance and inspection effort in proportion to the consequences of structural failure. Most commercial building steelwork in Europe is executed to EXC2. Bridges, grandstands and long-span roofs typically move to EXC3. Exceptional structures such as nuclear containment buildings reach EXC4.

This article explains what EN 1090-2 actually requires at each execution class, separates the certification documents an importer should demand (EN 10204 3.1 and 3.2 inspection certificates, FPC audit reports, WPQR records) from decorative paperwork, and provides a practical checklist for buying CE-compliant steel structures fabricated in China. It is written for project owners, main contractors and consulting engineers who need to verify compliance without becoming welding specialists themselves.

1. CE Marking and Its Prerequisites

CE marking for structural steel is not a product test; it is a factory-based conformity assessment. Under the CPR, load-bearing steel components are covered by Assessment and Verification of Constancy of Performance (AVCP) system 2+. The manufacturer performs Factory Production Control (FPC), and a notified body — a laboratory or certification body listed on the NANDO database — audits that FPC, carries out an initial inspection of the manufacturing plant, and performs continuous surveillance. Only after the FPC certificate is in place can the manufacturer issue a Declaration of Performance (DoP) and affix the CE mark.

Three practical consequences follow for buyers:

• The certificate travels with the factory, not with the cargo. A shipment of uncertified steel cannot be “CE-marked at the port”. The compliance decision must exist before fabrication begins.
• The scope of the FPC certificate matters. It should state the execution classes (EXC1-EXC4), the fabrication processes (cutting, welding, shot blasting, painting) and the component categories covered. A certificate covering only EXC1 is irrelevant to a bridge contract specifying EXC3.
• Material conformity feeds the DoP. Steel grades listed in the harmonised standards (EN 10025 series, EN 10210, EN 10219) are admissible; unaudited “equivalent” substitutions must be justified and accepted by the project before work starts.

2. Execution Classes EXC1-EXC4: Definitions and What Changes

EN 1090-2 links the execution class to the consequence class of EN 1990 and to the service category of the structure. The consequence class expresses the severity of failure consequences (CC1 low, CC2 medium, CC3 high); the usage category reflects occupancy levels and the magnitude of imposed loads. The table below summarises how the requirements scale from EXC1 to EXC4, including the weld acceptance levels defined in ISO 5817 that EN 1090-2 references.

Execution class	Typical structures (consequence class)	FPC and welding requirements	Inspection and weld acceptance
EXC1	Low-consequence structures with limited access: single-storey agricultural buildings, small storage sheds, temporary works (CC1)	FPC per EN 1090-2 Annex A; welding managed to EN ISO 3834-4 (elementary requirements); welders qualified to EN ISO 9606-1	Weld acceptance ISO 5817 level D; visual inspection on a documented sampling basis; EN 10204 2.2 or 3.1 certificates acceptable for basic grades
EXC2	Standard buildings: office and industrial halls, schools, warehouses — the default for most Eurocode-designed commercial structures (CC2)	FPC; welding per EN ISO 3834-3 (standard); weld procedure qualification to EN ISO 15614-1; heat-number traceability on primary members	Weld acceptance ISO 5817 level C; 100% visual inspection per ISO 17637; NDT sampling of full-penetration butt welds as specified; EN 10204 3.1 certificates on primary steel
EXC3	Bridges, grandstands, high-occupancy public buildings, long-span roofs; structures where collapse consequences are elevated (CC2 high usage / CC3)	FPC; welding per EN ISO 3834-2 (comprehensive); impact toughness verified at service temperature; traceability extended to secondary members	Weld acceptance ISO 5817 level B; volumetric NDT (UT to EN ISO 17640 or RT to EN ISO 17636) on full-penetration butt welds of primary members; surface checks on critical fillet weld toes
EXC4	Exceptional structures where collapse cannot be accepted: nuclear containment, security-critical infrastructure (CC3)	FPC; EN ISO 3834-2 plus project-specific additions; independent verification of procedures, welders and consumables	ISO 5817 level B with project additions; 100% volumetric NDT of full-penetration welds; EN 10204 3.2 certificates from independent inspection bodies are normally mandated

The engineering rationale behind the scale is straightforward: the higher the execution class, the smaller the tolerable defect and the more evidence the file must contain. A fabricator quoting “EN 1090-2 compliant” without naming an execution class has told you almost nothing.

3. Factory Production Control (FPC)

Annex A of EN 1090-2 defines the minimum content of the FPC system. In practice it is a documented quality-management framework built on ISO 9001 but with steel-specific additions. The elements inspectors look for are:

• Nominal staff and responsibility matrix: named welding coordinator, QC manager and NDT coordinator with defined authority.
• Welding control per EN ISO 3834: procedure qualification records (WPQR), welder certificates to EN ISO 9606-1, control of filler materials and shielding gases.
• Inspection, measuring and test equipment: calibration schedules for torque wrenches, thickness gauges, hardness testers and NDT instruments.
• Material identification and traceability: defined marking, storage and heat-number transfer rules from incoming plate to finished member.
• Non-conformity and corrective action: documented handling of rejected welds, out-of-tolerance members and defective materials.

The FPC audit is not a one-off. The notified body performs an initial inspection, then annual surveillance visits and periodic re-assessments. For an EU buyer, requesting the current FPC surveillance report — not a five-year-old trade-fair certificate — is a fast credibility test for any candidate supplier.

4. Welding Qualification and EN ISO 3834

Welding is the single most audited skill in an EN 1090-2 shop. EN 1090-2 Clause 12 and Table 10 tie the welding quality system to the execution class: EXC1 requires EN ISO 3834-4 (elementary), EXC2 requires EN ISO 3834-3 (standard), and EXC3 and EXC4 require EN ISO 3834-2 (comprehensive). Three document layers sit under that system:

• WPS and WPQR (EN ISO 15614-1): every joint geometry and welding position used in production must be backed by a qualified Welding Procedure Specification. WPQRs record parameters such as heat input, preheat, interpass temperature and shielding gas.
• Welder qualification (EN ISO 9606-1): each welder is qualified for specific processes, positions and thickness ranges, with validity maintained by continuous production evidence (revalidation every 6 months per clause 9 in the current edition).
• Consumable control: electrodes, wires and fluxes are selected per EN ISO 2560 (covered electrodes), EN ISO 14341 (solid wire for GMAW) or EN ISO 14171 / EN ISO 14174 (submerged arc wires and fluxes), stored and baked according to the manufacturer’s instructions.

Impact toughness deserves explicit attention because it is a common source of non-conformity. EN 10025-2 grade S355J2 guarantees 27 J Charpy V-notch at −20°C; S355K2 guarantees 40 J at −20°C. For EXC2 building structures this is usually sufficient. For EXC3, where brittle fracture is a design consideration, the project specification frequently requires weld and heat-affected-zone (HAZ) toughness to be demonstrated at the actual minimum service temperature, which means additional testing beyond the base-metal certificate. When buying from China, ask for the WPQR list and the Charpy records together — one without the other cannot be verified.

5. Material Traceability and Inspection Certificates

EN 1090-2 Clause 5.2 requires that incoming materials be identified and verified before use. In practice that means inspecting the mill certificate against the purchase order, checking the grade, dimensions and heat numbers, and transferring those identities onto the fabricated member so that every beam can be traced back to a specific cast. The certificate types are defined in EN 10204:

• Type 2.2: a declaration of conformity issued by the manufacturer, without test results. Acceptable for secondary material in EXC1, rarely enough for primary steel.
• Type 3.1: the manufacturer’s inspection certificate declaring that the products conform, with the relevant inspection and test results. This is the standard requirement for primary structural steel in EXC2 and above.
• Type 3.2: a certificate issued by the manufacturer and countersigned by an independent inspection body (such as SGS, TÜV or Bureau Veritas) after witnessing the tests. Typically specified for EXC3/EXC4 critical members, bridge steel and thick plates with demanding through-thickness properties.

Chinese mills routinely issue certificates that follow GB/T 17505 with content equivalent to EN 10204 3.1, but “equivalent” is not the same as “accepted”. Where the project specification names EN 10204 3.1 and a third party is appointed, the certificate must name that inspection body and the tests it witnessed. This is one of the most frequent causes of documentation disputes on EU-bound shipments, and it is cheapest to resolve in the purchase order, not at the port.

6. Buying Structural Steel from China for EU Projects: A Practical Checklist

Sourcing EN 1090-2 compliant fabrication from China is well established — several Chinese workshops now hold FPC certificates audited by European notified bodies — but the difference between a smooth project and a documentation crisis is decided by the checklist below:

• Specify European grades, not names. Order S235JR/J0/J2, S275JR/J0/J2 and S355JR/J0/J2 to EN 10025-2, S355M to EN 10025-4 for welded heavy sections, and hollow sections to EN 10210 (hot-finished) or EN 10219 (cold-formed) as applicable. Chinese equivalents exist — Q235B/C/D correspond broadly to S235JR/J0/J2 and Q355B/C/D to S355JR/J0/J2 — but equivalence must be confirmed by the project engineer and documented grade-by-grade.
• Verify the FPC certificate scope. It must name the notified body identification number, the execution classes, the plants and the processes. Check surveillance status with the body if in doubt.
• Demand the documentation file before fabrication: WPQR list, welder register with expiry dates, NDT personnel certificates to EN ISO 9712, and consumable storage procedures.
• Define acceptance levels in the contract: ISO 5817 C for EXC2, B for EXC3; tolerances per EN 1090-2 Annex D Class 2 as standard, Class 1 where architectural appearance demands it; NDT proportions per an agreed inspection and test plan (ITP).
• Appoint or accept a third-party inspector (SGS, TÜV, Intertek or a client-nominated body) with hold points for material certification, weld inspection and final release.
• Plan the lead time. Mill certification, FPC surveillance scheduling and third-party witnessing typically add 8-12 weeks beyond fabrication itself. Somebody asking for EN 1090-2 compliance “by Friday” has not understood the standard.

Our own fabrication facilities hold the Special-Class qualification for steel structure manufacturing in China and operate documented quality systems aligned with EN 1090-2 practice, including EN ISO 3834-based welding management, heat-number traceability and third-party-friendly inspection workflows. Details of our manufacturing qualifications and our approach to quality assurance are published separately. What matters for this article is the general rule: CE compliance is verifiable, documented and factory-based, and a serious buyer treats it as a contractual condition, not a marketing claim.

Key Takeaways

• EN 1090-2 is an execution standard. It controls fabrication, welding, tolerances and inspection; design remains the engineer’s responsibility under the Eurocodes.
• Execution class drives everything. EXC2 is the default for commercial buildings (ISO 5817 level C, EN ISO 3834-3); EXC3 adds level B acceptance and volumetric NDT for bridges and long-span structures; EXC4 is reserved for exceptional, fail-safe-critical works.
• CE marking is factory-based (AVCP system 2+). A notified body audits the FPC and surveys it annually; the certificate exists before fabrication, never at customs.
• Certificates have precise meanings. EN 10204 3.1 is the standard for primary steel; 3.2 adds independent witnessing and is normal for EXC3/EXC4 critical members.
• Buying from China works when the file is specified in the contract: European grades to EN 10025/EN 10210, FPC scope verification, WPQR and welder records, an agreed ITP, and 8-12 weeks of compliance lead time.

If you are planning a European project and need fabrication that will pass an EN 1090-2 audit — or if you are importing steelwork and want an independent review of a supplier’s compliance file — contact our engineering team. We can assess documentation, scope FPC requirements and put you in touch with the right certification bodies before the steel is ordered.