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Designing steel structures is an extremely responsible task that demands specialized knowledge and skills. To ensure the safety and reliability of these crucial elements of infrastructure, specific qualifications and competencies of the professionals involved are required. In this article, we will delve into the details of the requirements placed on individuals and companies engaged in designing steel structures.
Steel building structures are divided into three classes based on complexity, loads, and materials used. This classification directly translates into requirements for the contractors.
Class 3 structures are statically loaded, made of non-alloy structural steel not higher than category S235, with material thickness up to 30 mm. They do not contain specific structural-technological solutions.
Class 2 structures are statically or dynamically loaded (subjected to fatigue), made of non-alloy or low-alloy structural steel not higher than category S355. This also includes structures with special solutions such as prestressed bolted, fitted, or riveted connections.
Class 1 structures include those from Class 2, the failure of which could pose a significant risk to life or material losses. This also includes structures made of steel of a higher category than S355.
A key aspect of ensuring the quality of steel structures is the possession of appropriate competencies by the contractors. The norm PN-B-06200:2002 defines detailed criteria that companies engaged in structural construction must meet depending on their class.
Contractors for Class 3 structures must have group II facility authorizations and an implemented quality management system. Although certification of the system’s compliance with the PN-EN 729-4 standard is not required, the contractor must ensure the compliance of the elements produced with the PN-B-06200:2002 standard.
Contractors for Class 2 structures must have facility authorizations of group II or higher and an implemented quality management system compliant with the PN-EN 729-3 standard. If the system is not certified, the ordering party must conduct a compliance assessment.
Contractors for Class 1 structures must have a certified production quality management system compliant with the PN-EN 792-2 standard and meet the requirements for Class II structure contractors. Additionally, the ordering party must conduct continuous or individual compliance assessments.
The structural design documentation should include not only elements required by building law but also specific information essential for ensuring quality execution.
The documentation should encompass the technical project and a technical specification clearly defining the execution requirements, workshop drawings, steel and connector lists, assembly diagrams, and connection details.
The documentation should precisely define dimensional tolerances, scope and type of tests, acceptance criteria, weld class, surface preparation and treatment, technological limitations, dimensions and weights of elements, as well as anti-corrosion and fire protection methods.
The technical specification should also require the development of a quality plan, specifying requirements review, task division, special process procedures, a list of control tests, and principles for introducing changes and procedures in case of non-compliance.
Materials used for steel structures must meet strictly defined quality requirements. Each material should have a quality certificate or test results confirming its parameters.
The use of unmarked products is unacceptable as it prevents full identification. Steel materials, ropes, wires, electrodes, fluxes, and mechanical connectors must meet the requirements of standards indicated in the design documentation.
Material storage conditions must ensure the protection of their quality characteristics and the possibility of full identification. Materials should not be exposed to factors that could degrade their properties.
Contractors for steel structures must employ personnel with appropriate qualifications and experience confirmed by certificates, including welders, joint control personnel, and welding supervision.
Welders must have qualifications in accordance with the PN-EN 287-1+A1 “Welding – Examination of welders” standard. These qualifications require regular training and continuing professional practice.
Welding supervision must be conducted in accordance with the requirements of the PN-EN 719 “Welding – Welding supervision – Duties and responsibilities” standard. The supervising staff must possess appropriate qualifications.
Personnel performing non-destructive testing must have qualifications in accordance with the PN-EN 473 “Non-destructive testing – Qualification and certification of NDT personnel – General principles” standard.
The execution process of steel structures must take place under controlled conditions, following established procedures and technological instructions.
Ensuring complete and unambiguous information about requirements, in the form of design documentation, workshop drawings, control and test plans, and welding technological instructions (WPS), is crucial.
Conducting controls and tests in accordance with the agreements, using appropriate equipment, and ensuring full material and process traceability is necessary.
Welding technologies require recognition in the form of trial joint tests under the supervision of an authorized unit or documented experiences of their application.
Designing steel structures is an extremely responsible task, requiring professionals with specialized competencies confirmed by appropriate qualifications. Not only the qualifications of the personnel are crucial, but also ensuring high-quality materials, design documentation, and supervised execution processes. Only such a comprehensive approach guarantees the safety and reliability of these key elements of building infrastructure. Experts working at the KOBEX Design Office stand out with extensive experience, guaranteeing the success of the planned implementation. Find out for yourself!