A special German standard of the German Institute for Standardization (
) for manhole covers (sewage, etc.) that defines the requirements for covers in the D400 (
) load class. This standard defines the size, the materials and the weight in which the lid should withstand in order to the load.
Download document from Beuth Verlag (payment) https://www.beuth.de/de/norm/din-19584-2/154438761