What Is Inspection?
Structural steel inspection verifies that the steel load-bearing system conforms to the design and to the execution standard during shop fabrication and site erection. Under EN 1090 the execution class (EXC) directly determines the extent and the stringency of the inspection.
Why Is It Done?
The aim is to show that the load-bearing system will safely carry the loads it was designed for, and to catch in the shop those fabrication faults that are very costly to correct after erection.
Which Equipment Is Covered?
- Steel building and industrial structure fabrications
- Bridge and overpass structures
- Tower, mast and antenna structures
- Crane girders and platforms
- Prefabricated steel elements
Legal Basis and Interval
In industrial inspection the schedule comes not from legislation but from the project's inspection and test plan (ITP). Hold points and witness points are defined in the contract and inspection takes place at those points. Recurring checks during operation are planned under the asset integrity programme.
Scope of Inspection
- Verification of the execution class (EXC) and its associated requirements
- Material certificates and traceability
- Quality of cutting, drilling and edge preparation
- Fabrication tolerances: flatness, straightness, dimensions
- Weld seams: visual examination and NDT scope
- Bolted connections: bolt grade, pre-tensioning and torque check
- Surface preparation and corrosion-protection coating
- Coating thickness and adhesion check
- Erection: alignment, elevation, plumb and connection accuracy
- Fire-protection application (if present)
Related Standards
- ISO/IEC 17020
- EN 1090-1
- EN 1090-2
- ISO 3834-2
- EN ISO 5817
- ISO 8501-1
- EN ISO 12944
Method and Equipment
- Dimensional measuring equipment, tape measure and laser distance meter
- Total station or level (for erection control)
- Weld seam gauges
- Ultrasonic testing device and magnetic particle equipment
- Coating thickness gauge and adhesion tester
- Calibrated torque wrench and bolt pre-tension measuring instruments
Inspection Process
- 1Review of the Inspection and Test Plan (ITP)The project specification, the standard to be applied, hold/witness points and acceptance criteria are clarified.
- 2Document and Material CheckMaterial certificates (EN 10204), welding procedures (WPS/WPQR) and personnel qualifications are verified.
- 3In-process InspectionManufacturing is halted at the defined hold points; dimensional, assembly and pre-/post-weld checks are performed.
- 4Non-destructive TestingThe NDT methods required by the specification are applied; method and extent are set according to the weld class and the product standard.
- 5Final Inspection and TestingDimensional checks, hydrostatic/pneumatic testing or a functional test are carried out.
- 6Reporting and Documentation PackageInspection reports, NDT reports and test records are compiled in the manufacturing data book.
Nonconformities
Weld discontinuities beyond the acceptance level, fabrication dimensions outside tolerance and bolted connections whose preload cannot be verified are findings that must be corrected. Coating thickness below the specification is reported separately, because it directly shortens corrosion life.
Inspection Report
- Details of the inspection body and the inspection personnel
- Project, specification and standards applied
- Item and lot inspected, with traceability data
- Findings of the document check (material certificates, WPS/WPQR)
- Inspection and test results
- References to the NDT reports
- Nonconformity reports and their close-out status
- Conclusion and release statement
Accreditation
Inspection activities are carried out under ISO/IEC 17020, which requires the impartiality of the inspection body, the competence of its personnel and the validity of the inspection methods. Under the impartiality rule, a party that maintains or repairs an item of equipment cannot carry out the independent inspection of that same equipment. EUROLAB holds internationally recognised accreditation under ISO/IEC 17020, granted by accreditation bodies that are signatories to the ILAC mutual recognition arrangement; because accredited scope is defined per inspection type, it is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Inspections
Frequently Asked Questions
How is the execution class (EXC) determined?
It is determined under EN 1090-2 by jointly assessing the structure's consequence class, service category and production category; it is the designer's responsibility. As the EXC rises, the weld quality level, the scope of NDT and the tolerance requirements become stricter.
Is inspection sufficient for EN 1090 CE marking?
No, it is not sufficient. CE marking requires the manufacturer's factory production control (FPC) system to be certified by a notified body. Project inspection verifies the output of that system; it does not substitute for certification.
What is the difference between a hold point and a witness point?
At a hold point production stops and the next step cannot begin until the inspection body attends. At a witness point the inspection body is invited, but production may continue if it does not attend. Which step falls into which category is fixed contractually in the inspection and test plan (ITP).