This document specifies the energy efficiency grades, technical requirements and testing methods for fresh water centrifugal pump units.This document applies to centrifugal pump units equipped with electric motors or Power Drive Systems (PDS)within a rated voltage range of 100 V~1000 V, including: — Single-stage single-suction fresh water centrifugal pump units, single-stage double-suction fresh water centrifugal pump units, pipeline fresh water centrifugal pump units, multi-stage fresh water centrifugal pump units, and light-duty multi-stage fresh water centrifugal pump units; — Fresh water circulating pump units.