This International Standard• specifies a method of determining the total emitted acoustic power of ultrasonic transducers based on the use of a radiation force balance;• establishes general principles for the use of radiation force balances in which an obstacle (target) intercepts the sound field to be measured;• establishes limitations of the radiation force method related to cavitation and temperature rise;• establishes quantitative limitations of the radiation force method in relation to diverging and focused beams;• provides information on assessment of overall measurement uncertainties. This International Standard is applicable to:• the measurement of