The standard is to be used for round hinged covers of carbon steel, carbon with surface coating, and stainless steel for vessels and equipment that preferably serve process purposes.
DIN 28125-1:1989 history
2020DIN 28125-1:2020-04 Hinged closures, round - Part 1: Nominal diameter DN 150 to DN 800
2020DIN 28125-1:2020 Hinged closures, round - Part 1: Nominal diameter DN 150 to DN 800