Specifies the technical requirements for cold-formed steel hollow sections for structural purposes, for the six grades of steel that are suitable for welding. Grade C200 and all hot-formed grades have been deleted. It includes a new cold-formed grade C450 and grades with guaranteed impact performance at 0 degrees Celsius, namely C250L0 and C450L0. Tensile strengths of grades C250 and C350 are reduced to reflect the properties obtained on cold-formed sections.