NDT for Steel Structures in Belgium

Certified non-destructive testing for structural steelwork — ensuring compliance with EN 1090, verifying weld quality and guaranteeing the structural safety of your steel constructions.

Non-Destructive Testing for Steel Structures

Steel structures form the backbone of modern industrial and commercial construction. From warehouse frameworks and multi-storey car parks to industrial platforms, bridges and crane runway beams, structural steelwork must withstand significant mechanical loads, dynamic stresses and environmental exposure throughout its design life. The integrity of these structures depends fundamentally on the quality of the welded connections that join their individual components, making non-destructive testing an indispensable part of the fabrication and erection process.

The introduction of the European Construction Products Regulation and the harmonised standard EN 1090 for the execution of steel and aluminium structures has established clear requirements for the extent and type of non-destructive testing that must be performed on structural steelwork. The required NDT scope is determined by the Execution Class (EXC1 to EXC4), which in turn is defined by the consequence class, service category and production category of the structure. Higher execution classes demand more extensive inspection, including a greater percentage of weld examination and the use of volumetric NDT methods.

LCNDTEST, operating from Nivelles across the whole of Belgium, provides the complete range of NDT services required for structural steelwork inspection under EN 1090. Whether you are a steel fabricator requiring in-shop weld inspection, a construction contractor needing on-site erection inspection, or a building owner requiring a condition assessment of an existing structure, our certified technicians deliver thorough, code-compliant inspections with clear, well-documented reports that satisfy the requirements of your inspection and test plans.

Adapted Inspection Methods

The NDT methods applied to steel structures are selected based on the requirements of EN 1090-2, the execution class, the type of welded joint (butt weld, fillet weld, partial penetration weld) and the specific requirements of the inspection and test plan (ITP). LCNDTEST applies the appropriate combination of methods to provide comprehensive coverage of structural weld quality.
  • Visual Testing (VT) in accordance with EN ISO 17637 — the mandatory first inspection step for 100% of structural welds across all execution classes, verifying weld geometry, surface quality, dimensional compliance and the absence of visible defects
  • Magnetic Particle Testing (MT) for the detection of surface and near-surface cracks on fillet welds, butt welds and critical connection zones in carbon and low-alloy structural steels
  • Penetrant Testing (PT) for surface crack detection on non-ferromagnetic materials and in situations where magnetic particle testing is not applicable
  • Ultrasonic Testing (UT) for volumetric examination of full-penetration butt welds on primary structural members, verifying the absence of internal defects such as lack of fusion, lack of penetration, cracks and significant inclusions
  • Radiographic Testing (RT) as an alternative volumetric method where specified by the design engineer or where ultrasonic testing is technically limited (e.g., thin materials, complex geometries)
  • Phased Array Ultrasonic Testing (PAUT) for advanced weld inspection providing enhanced detection capability and documented imaging of the inspected volume — increasingly specified for high execution class structures
  • Hardness Testing on welds and heat-affected zones where required by the welding procedure or when verifying that maximum hardness limits are not exceeded in high-strength structural steels

Standards and Regulations

Structural steelwork inspection by LCNDTEST is performed in strict compliance with EN 1090-2 (execution of steel structures) and its referenced NDT standards. The required extent of non-destructive testing is determined by Table 24 of EN 1090-2 based on the execution class. For EXC2, a minimum percentage of welds must be examined using surface and volumetric methods. For EXC3 and EXC4, the inspection extent increases significantly, with EXC4 requiring the most comprehensive NDT coverage. Acceptance criteria for weld quality are defined by EN ISO 5817, with quality levels B, C or D specified according to the execution class and the type of welded joint. Our inspection reports reference all applicable standards and provide clear traceability from the inspection result to the acceptance criterion.

Frequently asked questions

The NDT requirements under EN 1090-2 depend on the execution class (EXC) of the structure. For EXC1, visual testing (VT) of all welds is the primary requirement. For EXC2, in addition to 100% VT, a defined percentage of welds must be examined by surface methods (MT or PT) and volumetric methods (UT or RT), typically 10% for butt welds and 5% for fillet welds. EXC3 increases these percentages further (typically 20% and 10%), and EXC4 requires the highest level of inspection. LCNDTEST helps fabricators and constructors determine the correct execution class and develop inspection plans that meet all EN 1090-2 NDT requirements.

Yes, LCNDTEST performs structural steelwork inspections both in fabrication workshops and on construction sites throughout Belgium. Workshop inspections enable the examination of welds under controlled conditions before the components leave the shop, while site inspections verify the quality of erection welds, bolted connections and any field modifications. Our portable NDT equipment is designed for use in challenging site conditions, including working at height, in confined spaces and in adverse weather. We coordinate closely with project teams to schedule inspections efficiently and minimise disruption to fabrication and erection programmes.

Absolutely. Non-destructive testing is a valuable tool for assessing the condition of existing steel structures, whether as part of a routine maintenance programme, a structural assessment following a change of use, or an investigation into suspected deterioration or damage. LCNDTEST performs condition assessments on existing steelwork including the detection of fatigue cracks at welded connections, measurement of corrosion-related material loss, verification of material grade by PMI, and hardness testing. The results provide the engineering data needed for structural assessment, repair planning and decisions regarding continued safe use.

Need a reliable inspection for your installations?

Our certified technicians respond promptly across all of Belgium. Contact us today for a customised quote and ensure the compliance of your equipment.