What is EN 1090 and why is it important?

EN 1090 is a harmonized European set of standards regulating the manufacture and conformity assessment of load-bearing steel and aluminum structural elements. In the European Union, the placing of construction building elements on the market is assessed under the Construction Products Regulation (CPR – Regulation 305/2011); EN 1090 is the harmonized standard that implements this regulation for steel and aluminum structural elements.

The standard series consists of three main parts. EN 1090-1 specifies the requirements for conformity assessment and factory production control for CE marking. EN 1090-2 covers the technical requirements for the manufacture of steel structures. EN 1090-3 addresses the manufacture requirements for aluminum structures.

CE marking of load-bearing steel structural elements has become a required framework for load-bearing elements placed on the European Union market since a certain date, in accordance with relevant regulations. The CE mark is a means of declaring that the product conforms to the relevant regulation and has been designed and manufactured according to a harmonized standard.

  • EN 1090-1: Conformity assessment and Factory Production Control (CE marking framework).
  • EN 1090-2: Technical requirements for the manufacture of steel structures.
  • EN 1090-3: Technical requirements for the manufacture of aluminum structures.
  • Legal basis: Construction Products Regulation (CPR — Regulation 305/2011).

Execution Classes: EXC1 – EXC4

EN 1090 grades the level of rigor required for manufacturing using four execution classes (EXC): EXC1, EXC2, EXC3, and EXC4. As the class increases, the manufacturing, welding, inspection, and traceability requirements become stricter.

The application class is determined based on the resulting weight of the structure in the event of a possible defect or collapse, as well as the usage and load conditions. EXC1 represents the mildest requirement regime, while EXC4 represents the most comprehensive regime for special structures with the highest risk. Determining the appropriate class is usually done during the design phase and according to the relevant national/design requirements.

  • EXC1: Lowest risk/requirement level.
  • EXC2: Intermediate level for common structural applications.
  • EXC3: High requirement level.
  • EXC4: The most comprehensive level for specialized structures with the most critical outcomes.

Factory Production Control (FPC) System

Factory Production Control (FPC – the manufacturer's continuous production quality control system in the factory) is the basis of EN 1090-1. The manufacturer demonstrates the conformity of its products to the standard through an FPC system, assessed and certified by an accredited/approved organization using relevant type tests, and then issues a Declaration of Performance.

FPC aims to ensure that manufacturing activities under EN 1090-2 are controlled in a traceable manner. In practice, it encompasses processes such as traceability of input materials and review of material documentation, welding procedures and welder qualification records, measurement equipment calibration, non-destructive testing records, and nonconformity management.

  • Incoming material traceability and review of material documentation.
  • Welding procedures and welder qualification records management.
  • Calibration of measuring and testing equipment.
  • Non-destructive testing records and management of nonconformities.

ISO 3834 Welding Quality Management System

ISO 3834 is an international series of standards defining quality requirements for fusion welding (joining metallic materials by melting). Since the quality of the weld is largely determined by the process itself, this standard aims to ensure that the manufacturer carries out its welding activities within a planned and controlled quality management system.

ISO 3834 offers three quality levels: ISO 3834-2 covers comprehensive quality requirements, ISO 3834-3 covers standard quality requirements, and ISO 3834-4 covers essential quality requirements. The appropriate level is associated with the risk of the manufactured product and its respective application class.

  • ISO 3834-2: Comprehensive quality requirements.
  • ISO 3834-3: Standard quality requirements.
  • ISO 3834-4: Essential quality requirements.

Relationship between EN 1090 and ISO 3834 and Welding Coordinator

EN 1090-2 links the two standards by requiring the relevant ISO 3834 quality level for specific application classes. In the general approach, higher application classes require a more comprehensive welding quality level; for example, for EXC3 and EXC4, the comprehensive level ISO 3834-2 is required. Thus, the manufacturer's welding quality management system becomes an integral part of the CE marking framework for the steel structure.

Under EN 1090-2, manufacturers are generally expected to appoint a welding coordinator for application classes EXC2 and above. The competence of the welding coordinator is assessed according to EN ISO 14731; this role can be fulfilled with qualifications such as International Welding Engineer (IWE), welding technologist (IWT), or welding specialist (IWS).

The details of weld seam inspection, welding procedure specification (WPS) preparation, and welder qualifications are beyond the scope of this page. For these topics, please refer to the welding inspection content covered in a separate information page.

  • EN 1090-2 specifies the required ISO 3834 level according to the application class.
  • For EXC3 and EXC4, the comprehensive ISO 3834-2 standard is generally required.
  • EXC2 and above are expected to have a resource coordinator assigned (EN ISO 14731).
  • Weld seam inspection, WPS (Waste Safety Plan), and welder qualifications are covered on separate pages.

Exports and the Turkish Context

For Turkish manufacturers supplying load-bearing steel or aluminum structural elements to the European Union market, the CE marking framework under EN 1090 is crucial. In the export of steel structures, roof/facade support systems, bridge elements, and similar load-bearing products to the European Union, this framework practically stands out as a market entry requirement.

In Türkiye, specifications referencing EN 1090 and ISO 3834 requirements are becoming increasingly common in both public and private sector projects. Therefore, steel structure manufacturers establishing Factory Production Control systems and welding quality management systems at an early stage provides predictability for both export and domestic projects.

  • The EN 1090 CE framework is the determining factor in the export of steel/aluminum structures to the European Union.
  • References to EN 1090 and ISO 3834 are becoming increasingly common in specifications in Türkiye.
  • Early implementation of FPC and welding quality systems provides predictability.

Information Note

This page is for informational purposes only and does not constitute technical advice or legal opinion. Determining the application class, selecting the required ISO 3834 level, and project-specific requirements vary according to the building conditions and should be assessed by a qualified engineer (mechanical engineer or civil/welding engineer in the relevant discipline).

AES is not a notified body or certification body; it does not issue EN 1090 Factory Production Control certificates, ISO 3834 certificates, or CE marks. EN 1090 and ISO 3834 certifications are only issued by accredited/notified bodies. AES only addresses these issues within the framework of preparation and implementation consultancy, and technical assessment/information.

AES's accreditation under the Turkish Accreditation Agency (TÜRKAK) is limited only to the 6.1 Electrical Installation area. The EN 1090 and ISO 3834 topics discussed on this page are not included within the scope of this accreditation.

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Frequently Asked Questions

What is EN 1090 and who needs it?

EN 1090 is a harmonized standard regulating the conformity assessment (EN 1090-1) for the manufacture of load-bearing steel (EN 1090-2) and aluminum (EN 1090-3) structural elements and for CE marking. It is relevant to manufacturers supplying load-bearing steel/aluminum structural elements to the European Union market.

What is an Execution Class (EXC)?

EXC1 to EXC4 is a classification that determines the level of rigor in manufacturing. The class is determined according to the resulting weight of the structure in a possible collapse and the operating conditions; as the class increases, manufacturing, welding, and inspection requirements become stricter. It is usually determined during the design phase.

What is the relationship between EN 1090 and ISO 3834?

EN 1090-2 specifies the required ISO 3834 welding quality level according to the application class. For example, for EXC3 and EXC4, the comprehensive ISO 3834-2 level is required. Thus, the welding quality management system becomes part of the CE marking framework for steel structures.

What is the difference between the quality levels of ISO 3834?

ISO 3834-2 defines comprehensive quality requirements, ISO 3834-3 defines standard requirements, and ISO 3834-4 defines fundamental quality requirements. The appropriate level is related to the risk of the product and its respective application class; higher application classes require a more comprehensive level.

How can I obtain EN 1090 or ISO 3834 certification? Does AES issue this certification?

EN 1090 Factory Production Control certificates and ISO 3834 certificates are issued only by accredited/notified bodies (Notified Bodies) following an audit of the manufacturer's system. AES is not a notified body or certification body; it does not issue these certificates or the CE mark.

What is AES doing about this?

AES addresses EN 1090 and ISO 3834 standards only through preparation and implementation consultancy, and technical evaluation/information. It does not conduct certification activities requiring accreditation. AES's TÜRKAK accreditation is limited to the 6.1 Electrical Installation field.