| Quality management | Documented quality-management system covering purchasing, fabrication, inspection, nonconformity control, and corrective action. | ISO 9001:2015 | Valid certificate issued by an accredited certification body; controlled procedures and internal audit records. | Check certificate scope, validity, site address, and certification-body accreditation. |
| Welding quality system | Qualified welding personnel, approved welding procedures, traceable consumables, and controlled welding parameters. | ISO 3834-2; AWS D1.1/D1.1M where specified | Welding procedure specifications, procedure qualification records, welder qualification records, and weld maps. | Review qualifications against the selected material, welding process, thickness, and project code. |
| Execution class capability | Production controls matched to the structural risk, design requirements, and installation environment. | EN 1090-1 execution classes EXC1–EXC4 | Factory production control documentation, inspection plans, traceability records, and declaration of performance where applicable. | Confirm the required execution class with the design engineer before contracting. |
| Structural steel grades | Common low-alloy structural grades include S275 and S355 under European specifications; ASTM A36 and ASTM A572 Grade 50 are also widely used. | EN 10025-2; ASTM A36/A572 | Mill test certificates showing chemical composition, mechanical properties, heat number, and product dimensions. | Verify that the specified grade, thickness, impact requirement, and delivery condition match the design. |
| Material traceability | Traceability maintained from incoming steel through cutting, assembly, welding, coating, and dispatch. | EN 10204 inspection documents; project quality plan | Heat numbers transferred to components, material registers, cutting lists, and final inspection records. | Request a sample traceability chain for one finished member. |
| Dimensional accuracy | Fabricated members controlled for length, straightness, squareness, hole position, camber, and assembly fit-up. | EN 1090-2; approved fabrication drawings and project tolerances | Calibrated measuring equipment, dimensional inspection reports, fit-up checks, and survey records. | Require a signed dimensional report for critical assemblies and connection zones. |
| Weld acceptance | Visual inspection of welds, with additional non-destructive testing based on design category and specification. | ISO 5817; ISO 17637; ISO 17635 | Visual inspection reports plus magnetic-particle, dye-penetrant, ultrasonic, or radiographic test reports when required. | Confirm test method, inspection percentage, acceptance level, and independent inspector involvement. |
| Surface preparation | Surface cleanliness and roughness selected according to the coating system and exposure category. | ISO 8501-1; ISO 8503; ISO 12944 | Abrasive-blasting records, surface profile measurements, dust checks, and soluble-salt checks where specified. | Specify preparation grade, profile range, coating system, and maximum time before priming. |
| Protective coating | Coating thickness and curing conditions controlled for the intended atmospheric or industrial environment. | ISO 12944; ISO 19840 | Dry-film-thickness readings, environmental logs, paint batch records, and repair records. | Review the complete paint data sheet and require readings at agreed inspection locations. |
| Hot-dip galvanizing | Zinc coating applied after suitable fabrication, cleaning, venting, and drainage preparation. | ISO 1461 | Visual inspection, coating-thickness measurements, repair records, and galvanizing certificate. | Confirm minimum local and mean coating requirements for the applicable steel thickness. |
| Cutting and drilling | CNC cutting, automated drilling, or controlled manual processes selected according to component complexity and tolerance. | Approved shop drawings; EN 1090-2 or project specification | CNC program records, tool calibration, hole-diameter checks, edge-condition checks, and first-piece inspection. | Ask for inspection records covering bolt-hole diameter, spacing, edge distance, and burr removal. |
| Assembly and fit-up | Trial assembly or controlled fit-up for complex frames, trusses, built-up members, and connection interfaces. | Approved fabrication drawings; project inspection and test plan | Fit-up checklists, temporary-connection records, bolt installation records, and photographic evidence. | Identify which assemblies require factory trial fitting before shipment. |
| Factory acceptance inspection | Final inspection completed before packing, including dimensions, welds, coatings, markings, and documentation. | Project inspection and test plan; contract quality requirements | Signed release note, punch-list closure, nonconformance reports, and final manufacturing dossier. | Define hold points and witness points for buyer or third-party inspection. |
| Packing and logistics | Members protected against impact, moisture, corrosion, deformation, and identification loss during transport. | Approved packing plan; shipping and lifting requirements | Packing lists, piece marks, lifting points, container-loading photographs, and shipping-weight records. | Check that piece marks correspond to erection drawings and packing lists. |
| Technical documentation | Complete document package supplied in the agreed language and format before or with shipment. | Contract document register; applicable national or project code | Approved drawings, material certificates, welding records, inspection reports, coating records, packing lists, and certificates of conformity. | Include document-submittal milestones and approval responsibilities in the purchase contract. |