New standard for fabrication of steel structures
A new European standard for the fabrication of constructional steelwork is being prepared by CEN committee and is expected to be published sometime in 2008. The BCSA is advising companies they need to familiarise themselves with this new standard now.
The standard is called BS EN 1090-2: Execution of steel structures and aluminium structures – Part 2: Technical requirements for the execution of steel structures. When published it will immediately replace current standards BS 5950 Part 2 (buildings), BS 5400 Part 6 (bridges) and BS 8100 (towers and masts).
Dr David Moore, BCSA Director of Engineering, said the new standard will introduce a number of issues that are different to the current British Standards for fabrication.
“More responsibility is placed on the steelwork contractor to get it right first time, and more reliance is placed on the knowledge and competence of staff.”
BS EN 1090-2 will also be a supporting standard for CE Marking, while it also introduces the concept of Execution Class. “In simple terms Execution Class determines the level of workmanship used to fabricate the structure,” explained Dr Moore.
“Four classes are introduced from Class 4 which is the highest quality to Class 1 which is lowest.”
The Execution Class can apply to the whole structure, but it can also apply to individual details. A building could be classified as Execution Class 2, but a particular feature, such as a detail subject to fatigue, could be classified as Class 3.
As part of the increase in responsibility, the standard also requires steelwork contractors to have in place a welding quality management system that conforms to the requirements of the relevant part of BS EN 3834.
BS EN 1090-2 will contain two types of tolerances, essential and functional. Both tolerances are mandatory, but essential tolerances are those that are declared as part of the CE Marking.