New to the Standard: This standard is an update to HI 40.6-2014 that incorporates exceptions made by the U.S. DOE in the Uniform Test Procedure for "Pumps" as outlined in Department of Energy - Energy Conservation Program (https://energy.gov/eere/buildings/standards-and-test-procedures). This standard established minimum testing protocols for testing of rotodynamic pumps for determination of pump efficiency in a uniform manner. This revision firmly aligns HI 40.6-2016 with the U.S. Department of Energy (DOE) energy conservation standards 81 FR 4368 (January 26, 2016) and test procedures 81 FR 4086 (January 25, 2016) for pumps, which incorporated by reference HI 40.6-2014 with certain exceptions and additions. This 2016 revision address the exceptions and additions. HI 40.6 is intended to be used testing at accredited pump test facilities, such as manufacturers' pump test facilities or laboratories only. Industry experience shows that it is very difficult to perform measurements accurate enough to satisfy the requirements in this standard when testing is performed in the field. Therefore field-testing is not permitted as a method of efficiency testing per this standard. This standard is not intended for production pump testing. Refer to ANSI/HI 14.6 Rotodynamic Pumps for Hydraulic Performance Acceptance Tests and ANSI/HI 11.6 Rotodynamic Submersible Pumps for Hydraulic Performance, Hydrostatic Pressure, Mechanical, and Electrical Acceptance Tests for production pump testing. Clarified the scope and body of the standard to clearly define the pumps under DOE regulation 10CFR 431.465 and its testing requirements. Provided greater detail in testing of pump types to the regulation, data collection, and external loses and how they are handled within the calculation of efficiency. Updates were made to the calculation of bare pump efficiency to the DOE regulation and requirements for plotting the data for the determination of the BEP rate of flow. Updated and improved the description and requirements of the pressure tap configuration for measurement sections at inlet and outlet of the pump. The electric input power measurement was expanded with required power quality and measurement as required to meet the DOE regulation for pumps as defined by the DOE for both bare pump efficiency determination and overall pump electrical power input. The addition of an informative appendix with examples on the determination of systematic uncertainty of the devices for measurement of required quantities on test. Scope: HI 40.6 is intended to be used for efficiency testing at pump test facilities or laboratories only. Industry experience shows that it is very difficult to perform measurements accurate enough to satisfy the requirements in this standard when testing is performed in the field. Therefore field-testing is not permitted as a method of efficiency testing per this standard.