Pipes and fittings of unplasticized poly(vinyl chloride) (PVC-U) for ducting – Dimensions and technical delivery conditions
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 03/01/2013

Pipes and fittings of unplasticized poly(vinyl chloride) (PVC-U) for ducting – Dimensions and technical delivery conditions
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 01/01/1998