ISO 5211:2017 specifies requirements for the attachment of part-turn actuators, with or without gearboxes, to industrial valves. The attachment of part-turn actuators to control valves in accordance with the requirements of this document is subject to an agreement between the supplier and the purchaser. ISO 5211:2017 specifies: - flange dimensions necessary for the attachment of part-turn actuators to industrial valves [see Figures 1 a) and 1 c)] or to intermediate supports [see Figures 1 b) and 1 d)]; - driving component dimensions of part-turn actuators necessary to attach them to the driven components; - reference values for torques for interfaces and for couplings having the dimensions specified in this document. The attachment of the intermediate support to the valve is out of the scope of this document.