IEC 60193:2019 applies to laboratory models of any type of impulse or reaction hydraulic turbine, storage pump or pump-turbine. This document applies to models of prototype machines either with unit power greater than 5 MW or with reference diameter greater than 3 m. Full application of the procedures herein prescribed is not generally justified for machines with smaller power and size. Nevertheless, this document may be used for such machines by agreement between the purchaser and the supplier. This document excludes all matters of purely commercial interest, except those inextricably bound up with the conduct of the tests. This document is concerned with neither the structural details of the machines nor the mechanical properties of their components, so long as these do not affect model performance or the relationship between model and prototype performances. This document covers the arrangements for model acceptance tests to be performed on hydraulic turbines, storage pumps and pump-turbines to determine if the main hydraulic performance contract guarantees (see 4.2) have been satisfied. It contains the rules governing test conduct and prescribes measures to be taken if any phase of the tests is disputed. The main objectives of this document are: – to define the terms and quantities used; – to specify methods of testing and of measuring the quantities involved, in order to ascertain the hydraulic performance of the model; – to specify the methods of computation of results and of comparison with guarantees; – to determine if the contract guarantees that fall within the scope of this document have been fulfilled; – to define the extent, content and structure of the final report. The guarantees can be given in one of the following ways: – guarantees for prototype hydraulic performance, computed from model test results considering scale effects; – guarantees for model hydraulic per...