This International Standard sets the requirements for conducting and reporting the results of a pumping system energy assessment (hereafter referenced as “assessment”) that considers the entire pumping system, from energy inputs to the work performed as the result of these inputs. The objective of a pumping system energy assessment is to determine the current energy consumption of an existing system and identify ways to improve system efficiency. These requirements consist of organizing and conducting an assessment, analysing the data from the assessment, and reporting and documenting assessment findings. This International Standard is designed to be applied, to open and closed loop pumping systems typically used at industrial, institutional, commercial, and municipal facilities, when requested. This International Standard is focused on assessing electrically-driven pumping systems, which are dominant in most facilities, but is applicable with other types of drivers, such as steam turbines and engines, and drives such as belt. The International Standard does not specify how to design a pumping system, give detailed qualifications and expertise required of the person using the International Standard although provides a list of body of knowledge in Annex C, address the training or certification of persons, specify how to implement the recommendations developed during the assessment, but does include requirements for an action plan, specify how to measure and validate the energy savings that result from implementing assessment recommendations, specify how to make measurements and how to calibrate test equipment used during the assessment, specify how to estimate the implementation cost or conduct financial analysis for recommendations developed during the assessment, specify specific steps required for safe operation of equipment during the assessment. The facility personnel in charge of normal operation of the equipment are responsible for ensuring that it is operated safely during the data collection phase of the assessment, address issues of intellectual property, security, confidentiality, and safety.