IEC 63132-4:2020 The purpose of this this part of IEC 63132 is to establish, in a general way, suitable procedures and tolerances for the installation of a vertical Kaplan or propeller turbine. This document presents a typical assembly and whenever the word "turbine" is used in this document, it refers to a vertical Kaplan or propeller turbine. There are many possible ways to assemble a unit. The size of the machine, design of the machine, layout of the powerhouse or delivery schedule of the components are some of the elements that could result in additional steps, the elimination of some steps and/or assembly sequences.