Kolk gate valves are made of ductile iron GJS-400/500 (DIN1693 GGG-40/50). Designed acc. to EN 1074-2 (DIN 3352-4) and EN 1171, flange drilling acc. to EN 1092-2 (ISO 7005-2). Face to face acc. to EN 558-1 (DIN 3202-1 F4). Epoxy coated (Resicoat®) acc. to EN 14901 (DIN 30677-2) and GSK certified (RAL-GZ 662). From DN 700 upwards standard equipped with gearbox.