DIN 83402-2
DIN 83402-2 Manhole covers with a nominal size of 600 × 400 for pressures up to 1.1 bar or 3 bar - Part 2: Frames, covers
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 08/01/2008
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 08/01/2008