To standardize the methods and equipment to enable the flow-rate of fluids in closed conduits to be determined by the measurement of the mean axial flow velocity or by the integration of the local velocities.

Examples of such equipment are as follows: electromagnetic flowmeters, ultrasonic flowmeters, coriolis mass flowmeters, instability methods (vortex, fluidic ...), velocity-area methods (current meters, Pitot tubes ...), tracer methods (di-lution method, transit time method, ...) etc.