For any project the required quality of fabrication or Execution Class must be specified. BS EN 1090–2 requires the Execution Class to be specified for:
The Engineer is responsible for specifying the Execution Class for the structure, the components and the details.
In some cases the Execution Class for the structure, the components and the details will be the same, while in other cases the Execution Class for the components and the details may be different to that for the whole structure.
N.B. Further detailed information can be found on the Steel Construction website: http://www.steelconstruction.info/CE_marking