There is no difference, all national standards followed by the prefix "EN" and of the same number are identical in the content of the standard. One European Standard = twenty-eight national standards. After the European Standard EN passed the Formal Vote and publication by CEN, each of the National Standards Bodies is obliged to adopt the EN as an identical national standard and to withdraw any pre-existing national standards, which are in conflict with the new EN. What must be considered, a national cover page might be added in front of the standard's body, in which deviations or restrictions might be given. Yet, we are not aware of any such situation on aluminium material standards.