NBN EN 14399-5:2005

This part of this European Standard specifies, together with prEN 14399-1, hardened and tempered plain washers intended for assembly with large series hexagon high-strength structural bolts and nuts with threads from M12 to M36 inclusive. Washers according to this standard can be applied under the nut only.
NOTE Attention is drawn to the importance of ensuring that the washers are correctly used if satisfactory results are to be obtained. For recommendations concerning proper application, reference to ENV 1090-1 is made.