EN 1090-1+A1:2012 is the European standard that regulates the requirements for the manufacture and assembly of steel structures and provides CE marking for the structures concerned. The standard applies to a variety of structures such as bridges, stairs, roofs and platforms, and sets out requirements for both the strength calculations of the structures and the manufacture and installation of the structures themselves.

If a structure complies with EN 1090-1+A1:2012, it can be CE-marked to confirm that it meets all the safety, health and environmental standards set out in the European Union's Construction Products Directive. This marking is mandatory in many European countries and is also important if the structure is exported abroad, as its compliance with safety standards can be verified and certified by the CE marking.