Introduction: Why welding standards are critical to manufacturing safety and reliability

In the industrial sector of Ukraine, metal structures are the basis of load-bearing elements of buildings, bridges, reservoirs, lifting and transport equipment and technological installations. The repair and modernization of these structures require strict welding standards, as mistakes can lead to catastrophic consequences: collapse of structures, injuries to personnel, production stoppages and financial losses.

Standards EN 1090-1:2009+A1:2011 (execution of steel and aluminum structures) and ISO 3834-2:2021 (welding quality requirements) establish mandatory requirements for welding processes, quality control and documentation. For Ukrainian enterprises that work on the European market or strive to meet international standards, their compliance is not only a matter of security, but also of competitiveness.

According to the State Labor Service of Ukraine, in 2023, 18% of industrial accidents were related to defects in welded joints in metal structures. At the same time, 65% of these cases could be prevented if the requirements of EN 1090 and ISO 3834.

Scope and responsible persons

Who is required to comply with the standards?

Requirements EN 1090 and ISO 3834 apply to:

• Manufacturers of metal structures (factories, shops, workshops);
• Enterprises performing repair and modernization of load-bearing structures (for example, repair of bridges, cranes, tanks);
• Subcontractors who perform welding work at high-risk facilities (chemical production, energy, mining industry);
• Technical supervision services and MRO departments responsible for welding quality control.

The EN 1090-1 standard requires certification of the manufacturer's quality system (CE-marking) for structures supplied to the EU market. In Ukraine, similar requirements are established by DSTU B EN 1090-1:2014 and DBN V.2.6-163:2010 (steel structures of buildings and structures).

What structures and materials are covered by the standards?

Performance class (EXC) determines the level of requirements for welding quality control. For example, EXC4 (the highest grade) requires 100% ultrasonic inspection of welds, while EXC1 allows visual inspection.

Key requirements of EN 1090 and ISO 3834 standards

The main requirements of the standards can be grouped in the following directions:

1. Qualification of personnel

• Welders must be certified according to EN ISO 9606-1:2017 (for steel) or EN ISO 9606-2:2004 (for aluminum).
• Welding technology engineers must be certified according to EN ISO 14731:2019.
• Periodic re-certification of welders - at least once every 2 years.

2. Technological processes of welding (WPS)

• Each welding process must be described in Welding Procedure Specification (WPS) according to EN ISO 15609-1:2019.
• WPS is subject to qualification by testing to EN ISO 15614-1:2017 (for steel) or EN ISO 15614-2:2005 (for aluminum).
• Acceptable welding methods: MMA (111), MIG/MAG (131/135), TIG (141), SAW (121).

3. Quality control of welded joints

4. Documentation and traceability

• Each metal structure must have a Declaration of Conformity (DoC) in the form EN 1090-1.
• Mandatory documents:
  • Certificates for raw materials (steel, electrodes, wire);
  • WPS and welder qualification protocols;
  • Reports on weld quality control;
  • Welding logs indicating the materials used and process parameters.
• The term of storage of documentation is at least 10 years.

Impact of standards on MRO processes

Compliance with EN 1090 and ISO 3834 requires significant changes in approaches to maintenance and repair of metal structures:

1. Purchase of materials and components

• Electrodes, welding wire and fluxes must have EN ISO 14341:2020 (for MIG/MAG) or EN ISO 2560:2020 (for MMA) conformity certificates.
• Example: for welding steel S355J2+N, it is recommended to use electrodes E 38 4 B 42 H5 (according to EN ISO 2560) with a minimum impact strength of 47 J at -20°C.
• It is forbidden to use non-certified materials, even if they are cheaper. For example, electrodes without EN ISO 2560 marking can lead to cracking when welding under load.

2. Maintenance of welding equipment

• Welding machines must undergo periodic inspection in accordance with EN 60974-4:2016 (at least once a year).
• The permissible deviation of the arc voltage is no more than ±5% of the nominal value.
• Mandatory calibration of measuring devices (ammeters, voltmeters) - at least once every 6 months.

3. Documentation of repair works

• Each repair of a metal structure must be accompanied by:
  • Act of the technical condition of the structure before the repair;
  • A technological map of the repair with a reference to the approved WPS;
  • Protocol for quality control of welds after repair;
  • Act of acceptance of works with signatures of responsible persons.
• Example: when repairing a crane beam, it is necessary to record:
  • Type and dimensions of the defective area;
  • Defect removal method (mechanical, thermal);
  • Welding parameters (current, voltage, speed);
  • Control results (VT + UT for EXC3).

Requirements for components and spare parts

To ensure compliance with EN 1090 and ISO 3834 standards, certified components must be used:

All materials must have type 3.1 certificates according to EN 10204:2004, which confirm their chemical composition and mechanical properties. For example, for S355J2+N steel, the certificate must contain data on the carbon content (≤0.22%), manganese (≤1.6%), as well as the results of tensile tests (yield strength ≥355 MPa) and impact toughness (KV ≥27 J at -20°C).

For enterprises that do not have the opportunity to independently check the suppliers' certificates, it is recommended to purchase materials from verified suppliers, such as UNITEC-D E-Catalog, which presents certified welding materials and components with relevant documents.

Checklist for checking compliance with standards EN 1090 and ISO 3834

This checklist is intended for use by MRO services and technical control departments before starting repair work:

1. The performance class (EXC) of the structure is determined according to the project documentation.
2. Available certificates for raw materials (steel, electrodes, wire) for EN 10204 (type 3.1).
3. Welders have valid certificates according to EN ISO 9606-1/2.
4. Welding technology engineer certified according to EN ISO 14731.
5. Developed and approved WPS for this type of welding (according to EN ISO 15609-1).
6. WPS qualified under EN ISO 15614-1/2.
7. The welding equipment has been inspected for EN 60974-4 (not older than 12 months).
8. Measuring devices (ammeters, voltmeters) are calibrated (not older than 6 months).
9. A technological repair map with reference to WPS has been prepared.
10. Input control of materials was carried out (visual inspection, marking check).
11. The welding workplace is prepared (protection from wind, moisture, dust).
12. Proper storage of welding materials is ensured (electrodes in an oven at 120–150°C).
13. The metal is preheated (if required by WPS, for example, for thickness >20 mm).
14. Welding is performed according to WPS parameters (current, voltage, speed).
15. After welding, a visual inspection (VT) was carried out according to EN ISO 17637.
16. Additional control is performed (UT/RT/MT/PT) depending on EXC.
17. A quality control protocol for welds has been drawn up.
18. A certificate of the technical condition of the structure after repair was drawn up.
19. All documents (WPS, certificates, protocols) are stored in the archive for at least 10 years.
20. The design is marked according to the requirements of EN 1090-1 (CE-marking for the EU market).

Typical violations and how to avoid them

Auditors and technical supervision bodies most often detect the following violations:

1. Absence or invalidity of welders' certificates

• Problem: 30% of enterprises use welders without certificates or with expired certificates.
• Solution: keep a staff qualification log and plan re-certification 2 months before the certificates expire.

2. Use of uncertified welding materials

• Problem: 25% of enterprises buy electrodes or wire without EN 10204 certificates, which leads to weld defects.
• Solution: check availability of certificates from suppliers and keep copies of documents. For critical structures, use materials with type 3.1 or 3.2 certificates.

3. Absence or non-compliance of WPS

• Problem: 40% of enterprises do not have approved WPS or use outdated versions.
• Solution: develop WPS for each type of welding and conduct their qualification according to EN ISO 15614-1/2. Update WPS when materials or technology change.

4. Insufficient quality control of welds

• Problem: 35% of companies limit themselves to visual inspection only, without performing UT or RT for EXC3/EXC4 designs.
• Solution: Comply with the scope of control requirements of the standards (eg 100% UT for EXC4). Engage certified specialists in non-destructive testing.

5. Incomplete or missing documentation

• The problem: 50% of enterprises do not keep welding logs or do not keep control protocols.
• Solution: implement an electronic document management system for welding works. Appoint responsible persons for keeping and storing documentation.

Penalties and liability for non-compliance with standards

Failure to comply with EN 1090 and ISO 3834 entails serious legal and financial consequences:

1. Administrative responsibility

• Fines for violation of industrial safety requirements (Article 271 of the Code of Ukraine on Administrative Offenses):
  • For officials - from UAH 17,000 to UAH 34,000;
  • For legal entities - from 85,000 to 170,000 UAH.
• Suspension of operation of the object until the violations are eliminated (decision of the State Labor and Development Authority).

2. Civil liability

• Compensation for damages in the event of an accident caused by welding defects:
  • The cost of restoring the structure (for example, repairing a crane beam - from UAH 500,000);
  • Compensation for simple production (average daily losses for a metallurgical plant - from UAH 2,000,000);
  • Compensation for damage to the health of employees (according to Article 1166 of the Civil Code of Ukraine).

3. Criminal liability

• According to Art. 271 of the Criminal Code of Ukraine (violation of labor protection legislation):
  • Fine up to UAH 170,000;
  • Restriction of freedom for up to 5 years;
  • Imprisonment for up to 8 years (in case of death).
• Example: in 2022, the shop manager of a metallurgical plant was sentenced to 4 years in prison for a crane accident caused by poor-quality welding of a repair site.

4. Implications for insurance and contracts

• Refusal of insurance companies to pay for accidents caused by non-compliance with standards.
• Termination of contracts with European partners due to lack of CE marking.
• Loss of public procurement tenders (EN 1090 compliance requirement for construction sites).

Conclusion: How to ensure compliance and minimize risk

Compliance with EN 1090 and ISO 3834 standards is not only a formal requirement, but a critical element of safety and reliability of industrial metal structures. For Ukrainian enterprises, this is also a way to integrate into the European market and increase competitiveness.

Key steps to ensure compliance:

1. Conduct an audit of the current welding processes and documentation for compliance with the requirements of the standards.
2. Certify welders and process engineers according to EN ISO 9606 and EN ISO 14731.
3. Develop and qualify WPS for all types of welding operations.
4. Ensure the purchase of certified welding materials and components. A reliable supplier of such materials is UNITEC-D E-Catalog, which presents electrodes, wire, fluxes and shielding gases with all necessary certificates.
5. Implement a welding quality control system in accordance with EXC requirements.
6. Keep complete and accurate documentation at all stages of repair.

Remember: every weld defect is a potential accident. Investments in compliance pay off in reduced risks, increased durability of structures and avoidance of fines.

Sources and regulatory documents

1. EN 1090-1:2009+A1:2011 – Execution of steel and aluminum structures. Part 1: Requirements for conformity assessment of structural elements.
2. DSTU B EN 1090-1:2014 – Execution of steel and aluminum structures. Part 1: Requirements for conformity assessment of design elements (IDT).
3. ISO 3834-2:2021 – Requirements for the quality of fusion welding of metallic materials. Part 2: Comprehensive quality requirements.
4. EN ISO 9606-1:2017 – Qualification tests of welders. Fusion welding. Part 1: Steel.
5. EN ISO 14731:2019 – Welding coordination. Tasks and duties.
6. EN ISO 15609-1:2019 – Technical conditions and qualification of welding technologies of metallic materials. Technical conditions for welding technology. Part 1: Arc welding.
7. EN ISO 15614-1:2017 – Technical conditions and qualification of welding technologies of metallic materials. Testing of welding technology. Part 1: Arc and gas welding of steel and arc welding of nickel and nickel alloys.
8. DBN V.2.6-163:2010 – Steel structures. Standards of design, manufacture and installation.
9. Law of Ukraine "On Labor Protection" dated 14.10.1992 No. 2694-XII.
10. Code of Ukraine on Administrative Offenses (Article 271).
11. Criminal Code of Ukraine (Article 271).

1. Introduction

The structural integrity of metal structures is the basis of the safety of any industrial enterprise. Any violations in the performance of repair welding work can lead to catastrophic consequences: from the stoppage of production lines to accidents with human casualties. Standards EN 1090 and ISO 3834 establish strict requirements for the design, manufacture and repair of steel structures, ensuring their durability and reliability.

2. Scope of application

These standards apply to all load-bearing steel structures used in industrial construction and equipment. This applies to building frames, support structures for pipelines, conveyor systems, storage equipment and other components that are under constant or variable loads. Any repair of such elements by welding requires strict adherence to established procedures.

3. Basic requirements

For effective quality management during repair work, it is necessary to be guided by the classification of execution classes (EXC). Below is a summary table of requirements:

For most repair work at production facilities, class EXC2 or EXC3 is used. The terms of repairs must be clearly regulated in the maintenance plan.

4. Impact on MRO processes

Implementation of the EN 1090 and ISO 3834 requirements requires a review of maintenance, repair and operation (MRO) processes. First of all, it is necessary to implement a system of quality control of welding processes (ISO 3834). Documentation becomes a critical element: every weld must have a record of welder qualification (WPQ), welding process sheet (WPS) and non-destructive testing (NDT) results.

5. Requirements for components

Spare parts and consumables used in repairs must have appropriate quality certificates. Steel must meet EN 10025, and welding materials (electrodes, wire) must meet requirements for chemical composition and mechanical properties. The use of non-certified fasteners or steel profiles without proper CE marking is unacceptable.

6. Compliance Checklist for a safety engineer

1. Checking the presence of a valid ISO 3834 certificate at the contractor or own workshop.
2. Availability of approved WPS (welding technology cards) for each type of connection.
3. Verification of qualification certificates of welders in accordance with ISO 9606.
4. Checking the presence of certificates of conformity for the base metal (EN 10204).
5. Checking the availability of certificates for welding materials (electrodes/wire).
6. Definition of the execution class (EXC) for a specific node of the structure.
7. Preparation of control and test plan (ITP).
8. Visual control of the prepared edges of the connection.
9. Control of gaps and tacks before the main welding.
10. Measurement of welding parameters (current, voltage, speed).
11. Marking of welds to identify the welder.
12. Carrying out visual control of finished seams (VT) according to ISO 17637.
13. Carrying out additional NDT methods (ultrasound, magnetic powder control) in accordance with EXC.
14. Drawing up a report on the control results.
15. Approval of repairs by a quality engineer or a responsible person.
16. Archiving of documentation in the technical passport of the equipment.
17. Conducting a final inspection before putting the structure into operation.
18. Checking the presence of construction markings (repair data plate).
19. Training of personnel in safe methods of work during repairs.
20. Conducting an internal compliance audit for the year.

7. Common inconsistencies

During audits, the following violations are most often found: use of welders without valid certification, lack of non-destructive control protocols for responsible seams, use of materials without manufacturer's certificates, violation of requirements for storage and drying of electrodes.

8. Liability and penalties

Failure to comply with the requirements of the standards entails serious consequences. In the event of an accident, the absence of documentation of compliance (EN 1090) results in the insurance company refusing to pay compensation. In addition, administrative fines may be imposed on the enterprise by state bodies supervising labor protection. In cases that lead to injuries, responsible engineers and managers are criminally liable.

9. Conclusion

Compliance with EN 1090 and ISO 3834 standards is not a formality, but a mandatory condition for the safe operation of industrial equipment. The use of quality components and a qualified approach to welding work minimize the risks of emergency stops. Order only certified spare parts and components for your metal structures from the UNITEC-D E-Catalog to ensure full compliance of your repair work with modern engineering standards.

10. Links

• EN 1090-1:2009+A1:2011 "Performance of steel and aluminum structures"
• EN 1090-2:2018 "Technical requirements for steel structures"
• ISO 3834-2:2021 "Requirements for the quality of fusion welding of metallic materials"
• DSTU EN 1090-2:2014 "Performance of steel structures and structures from aluminum alloys"