Welding Standards EN 1090 and ISO 3834: Compliance with Requirements for Repair of Metal Structures

1. Introduction: The Critical Role of Welding Standards in Industry

The integrity of metal structures is a fundamental factor in the safe and uninterrupted operation of any industrial enterprise. Repair works, especially those related to load-bearing elements, require not only high qualification of executors, but also strict compliance with established international and national standards. Among them, standards EN 1090 (Performance of steel and aluminum structures) and ISO 3834 (Requirements for the quality of fusion welding of metallic materials) occupy a key place, determining the quality and safety of welding works.

Failure to comply with these regulations can lead to catastrophic consequences: from structural damage and personnel injuries to significant financial losses due to production shutdowns. Therefore, for maintenance managers, safety professionals and plant engineers, understanding and applying these standards is critical to ensure equipment longevity and market compliance. In Ukraine, compliance with international standards is often confirmed through the UkrSEPRO certification system, which emphasizes their importance for the local market.

2. Scope and Eligibility: Who Must Comply

EN 1090: Execution of Steel and Aluminum Structures

The EN 1090 standard consists of several parts, where EN 1090-1 establishes requirements for assessing the conformity of load-bearing structural components (steel and aluminum) placed on the market as construction products. EN 1090-2 details the technical requirements for the execution of steel structures. This standard is mandatory for manufacturers, assemblers, as well as for enterprises that repair load-bearing metal structures that affect their static or dynamic characteristics. Its effect extends to a wide range of objects, including elements of buildings, bridges, crane installations, overpasses, as well as frames and supports of equipment at industrial enterprises. The standard distinguishes four performance classes (EXC1, EXC2, EXC3, EXC4), each of which sets different levels of requirements for quality, control and documentation depending on the level of risk and consequences of possible destruction.

ISO 3834: Quality Requirements for Fusion Welding

ISO 3834 is a quality control system for welding processes applied to manufacturers who perform welding of metal materials. Unlike EN 1090, which is a product standard (for building products), ISO 3834 focuses on the process. It defines complex requirements for the quality of welding at all stages: from design and preparation of materials to direct welding, control and post-weld processing. This standard has three quality levels (Part 2: Comprehensive quality requirements, Part 3: Standard quality requirements, Part 4: Elementary quality requirements), which allows enterprises to choose the appropriate level depending on the complexity of the welded products and their purpose. It is used in all industries where welding is a critical process: heavy engineering, energy, chemical industry, shipbuilding and, of course, repair departments of industrial enterprises.

Thus, EN 1090 regulates the manufacture and repair of structural components, and ISO 3834 provides a quality management system for the welding process, regardless of the type of product. Both standards are complementary to ensure reliability and safety.

3. Key Requirements: Tabular Overview of Basic Obligations

For clarity, the main requirements of EN 1090 and ISO 3834 standards, critical for repair operations, are presented in the table below.

4. Impact on Maintenance and Repair Operations (MRO)

The implementation and maintenance of compliance with EN 1090 and ISO 3834 standards significantly changes approaches to the organization of M&R at the enterprise. These changes include:

• Qualification of Personnel:

  There is a need for qualified welding personnel. These are not only welders, but also welding production engineers, welding coordinators (according to EN ISO 14731), welding inspectors. Welders require regular certification to EN ISO 9606, which guarantees their ability to perform welding according to defined procedures. In addition, non-destructive testing personnel must be qualified according to EN ISO 9712 to perform ultrasound, MPD, VT, etc.

• Repair procedures:

  Every repair involving welding of load-bearing structures must have a well-defined and qualified welding procedure specification (WPS) developed on the basis of the welding procedure qualification protocol (PQR) according to EN ISO 15614. This requires detailed planning, including the selection of materials, welding consumables, welding mode parameters, welding sequence and control methods. It replaces impulsive decisions with unified, proven methods.

• Documentation and Traceability:

  The amount of necessary documentation is growing significantly. This includes material certificates (for example, EN 10204 3.1 or 3.2), welding consumables certificates, equipment passports, calibration reports, welder and inspector qualification certificates, NC reports, WPS, PQR, and records of each welding repair performed. Traceability of all stages from the delivery of materials to the final inspection is mandatory, ensuring that every element of the repair meets the standards.

• Investments in Equipment:

  Welding and inspection equipment may need to be upgraded to ensure compliance. This includes not only the welding equipment itself (which must provide stable parameters), but also measuring devices, NC systems, as well as systems for tracking and documenting processes. For example, the accuracy of the ammeter can be within ±5% according to GOST 8.028, which is sufficient for most applications, but for critical welds EN 1090-2 requires more strict parameter control.

• Interaction with Suppliers:

  Purchasing departments must cooperate exclusively with suppliers who can guarantee compliance of materials and components with the requirements of the standards by providing the necessary quality certificates. At the same time, UNITEC-D is a reliable partner that supplies certified components that fully meet the most stringent requirements.

5. Requirements for Components and Spare Parts

To ensure compliance with EN 1090 and ISO 3834 standards, the selection and quality of spare parts and components used for repairing metal structures is critically important. They include:

• Structural Steels:

  Beams, columns, sheet metal, profiles used for repair or replacement of load-bearing elements. They must meet material standards, for example EN 10025 (Hot-rolled structural steel products) and have appropriate quality certificates (for example, EN 10204 type 3.1 or 3.2) confirming the chemical composition, mechanical properties and traceability to the melt. The minimum yield strength of S355 can be 355 MPa, and the tensile strength is 490-630 MPa.

• Welding consumables:

  Electrodes, welding wire, fluxes, protective gases. They must comply with standards ISO 2560 (electrodes for manual arc welding), ISO 14341 (wire and rods for arc welding of non-alloy and fine-grained steels) or other relevant standards. Certificates from the manufacturer confirming compliance with the chemical composition and mechanical properties of the deposited metal are mandatory. Storage should be carried out in conditions that prevent moisture absorption (for example, at a temperature of 15-25 °C and a relative humidity of 40-60%).

• Carpentry Products:

  High-strength bolts, nuts and washers for joints subjected to loads must comply with EN 14399 (High-strength bolted joints for metallic structures) or EN 15048 (Bolted joints for metallic structures). It is important to check the strength marking (eg 8.8, 10.9) and the presence of certificates of conformity.

• Bearing Elements and Nodes:

  Any pre-manufactured subassemblies or components coming from external suppliers must have a CE declaration of conformity (for components subject to EN 1090-1) and proof of welding quality according to ISO 3834 from the manufacturer. This can apply, for example, to ready-made brackets, trusses or elements of platforms.

Each of these components plays a critical role in the overall reliability of the repaired structure. The failure of even one element due to a mismatch can compromise the entire system. UNITEC-D, as a trusted supplier, ensures that all products intended for responsible applications meet these strict requirements, ensuring full traceability and certification.

6. Compliance Checklist: A Practical Guide for Maintenance Managers

This checklist will help maintenance managers and safety professionals assess the level of compliance of their welding operations:

1. Has a welding quality management system (WQMS) in accordance with ISO 3834 (eg Part 2 or 3) been developed and implemented at the facility?
2. Is a Welding Coordinator appointed and certified (according to EN ISO 14731) with the appropriate level of knowledge to supervise the welding work?
3. Do all welders have valid EN ISO 9606 qualification certificates for the materials being welded and the processes used?
4. Are EN ISO 15614 welding procedure specifications (WPS) developed and qualified for all typical metalwork repairs?
5. Are welding procedure qualification records (PQRs) maintained and maintained?
6. Is the incoming control of all metals and welding consumables carried out with the verification of certificates (EN 10204 3.1/3.2)?
7. Is proper storage of welding consumables (electrodes, wire, fluxes) ensured in accordance with the manufacturer's recommendations?
8. Is there a reliable mechanism for tracing materials from the warehouse to a specific weld?
9. Are all welding machines and measuring equipment regularly calibrated according to the schedule and standards (eg DSTU EN ISO 17662)?
10. Is visual inspection (VT) of welds performed in accordance with EN ISO 17637?
11. Are additional NC methods (ultrasound, MPD, RT) carried out in accordance with EN 1090-2 requirements (for the corresponding EXC performance class) and/or ISO 3834 requirements?
12. Are NC personnel qualified according to EN ISO 9712 to perform the relevant control methods?
13. Are all NC results, test reports and reports recorded and stored?
14. Is there a clear procedure for managing nonconformities and corrective actions?
15. Are contractors (performing welding works) checked for compliance with EN 1090 and ISO 3834 standards?
16. Are all repairs (especially for load-bearing structures) designed and approved by a competent engineer?
17. Are welding and M&E personnel regularly trained on updates to standards and best practices?
18. Has a system been implemented for the timely identification and marking of load-bearing elements subject to welding repair?
19. Are the requirements of UkrSEPRO taken into account for welding works and components in Ukraine?
20. Is there a mechanism for analyzing the causes of weld damage and implementing preventive measures?

7. Typical Problems of Inconsistency

Audits and inspections often reveal the following typical deficiencies in compliance with welding standards:

• Lack of Welding Coordinator: Failure to appoint or lack of a competent Welding Coordinator with appropriate qualifications (e.g. IWT, IWE) according to EN ISO 14731.
• Expired Qualification of Welders: Execution of welding work by welders whose qualification certificates according to EN ISO 9606 are invalid or do not correspond to the performed processes/materials.
• Lack of Qualified WPS: Performing welding repairs without using qualified and approved welding procedure specifications (WPS) according to EN ISO 15614.
• Improper Input Control of Materials: Use of metals or welding consumables without checking quality certificates (EN 10204) or with unknown traceability.
• Inadequate Non-Destructive Control: Failure to perform required types of NC, use of unqualified NC personnel (without EN ISO 9712) or lack of proper registration of control results.
• Insufficient Documentation: Absence of complete and up-to-date welding records including WPS, PQR, welder qualifications, NC reports, calibration records.
• Uncalibrated Equipment: Using welding equipment that has not been calibrated in time, which can lead to unstable welding parameters (for example, current ±10A, voltage ±1V).
• Violation of Materials Storage Conditions: Improper storage of welding consumables, which leads to their moistening and deterioration of the quality of welds (for example, an increase in hydrogen content).

8. Penalties and Liability: Consequences of Non-Compliance

Non-compliance with EN 1090 and ISO 3834 standards entails serious legal, financial and reputational consequences, which can be significant for Ukrainian industrial enterprises:

• Administrative Fines and Orders:

  State regulatory bodies (for example, the State Labor Service of Ukraine) can impose significant fines for violations of occupational health and safety regulations. For example, fines from thousands to hundreds of thousands of hryvnias can be imposed for violation of labor legislation. In addition, orders may be issued to suspend the operation of the equipment or completely stop production until the identified deficiencies are eliminated. Outages can last for weeks, resulting in millions of dollars in downtime.

• Criminal Liability:

  In cases where non-compliance with standards leads to serious accidents, injuries or deaths of people, guilty persons (managers of enterprises, engineers responsible for M&R) may be held criminally liable in accordance with the Criminal Code of Ukraine (for example, Articles 271, 272). This may involve imprisonment for up to several years.

• Civil Liability:

  The enterprise bears civil liability for damage caused to third parties (for example, neighboring enterprises, the population) as a result of an accident or destruction of structures caused by poor welding. Claims can amount to millions, and lawsuits can last for years.

• Consequences for Insurance:

  Insurance companies may refuse to pay compensation for damages if it is proven that the accident occurred due to non-compliance with established norms and standards. This means that the company will be forced to cover all losses on its own. In addition, insurance premiums for enterprises with a low level of security can increase significantly (by 20-50%).

• Loss of Trust and Reputation:

  Accidents related to poor-quality welding cause irreparable damage to the company's reputation, lead to the loss of customers and partners, which is especially critical in the market of industrial services. Rebuilding trust can take years and will require significant investment in marketing and PR.

• UkrSEPRO requirements:

  For Ukrainian manufacturers and importers who work with products subject to mandatory conformity assessment, the availability of UkrSEPRO certificates is important. Failure to comply with the requirements underlying these certificates (including EN/ISO standards) may lead to the revocation of certificates and the prohibition of selling products on the market.

9. Conclusion

Compliance with welding standards EN 1090 and ISO 3834 is not just a formal requirement, but a fundamental basis for ensuring the safety, reliability and durability of industrial metal structures. Investments in personnel qualifications, equipment modernization, implementation of strict control and documentation procedures, as well as the use of certified materials, are economically justified and prevent much greater damage from accidents and fines.

UNITEC-D is your reliable partner in this process. We supply a wide range of certified components and spare parts that meet the highest international standards, including EN 1090 and ISO 3834. requirements.

To ensure the reliability and compliance of your welding work with EN 1090 and ISO 3834 standards, visit the UNITEC-D E-Catalog.

10. List of Used Standards and References

• EN 1090-1:2009+A1:2011 Execution of steel structures and aluminum structures - Part 1: Requirements for conformity assessment of structural components
• EN 1090-2:2018 Execution of steel structures and aluminum structures - Part 2: Technical requirements for steel structures
• ISO 3834-2:2021 Quality requirements for fusion welding of metallic materials - Part 2: Comprehensive quality requirements
• ISO 3834-3:2021 Quality requirements for fusion welding of metallic materials - Part 3: Standard quality requirements
• EN ISO 14731:2019 Welding coordination - Tasks and responsibilities
• EN ISO 9606-1:2017 Qualification testing of welders - Fusion welding - Part 1: Steels
• EN ISO 15609-1:2019 Specification and qualification of welding procedures for metallic materials - Welding procedure specification - Part 1: Arc welding
• EN ISO 15614-1:2017 Specification and qualification of welding procedures for metallic materials - Welding procedure test - Part 1: Arc and gas welding of steels and nickel alloys
• EN ISO 9712:2022 Non-destructive testing - Qualification and certification of NDT personnel
• EN 10204:2004 Metallic products - Types of inspection documents
• DSTU EN ISO 17662:2019 Welding. Calibration, validation and verification of arc welding equipment (EN ISO 17662:2016, IDT)