Defines pulsating flow, compares it with steady flow, and indicates the requirements that allow accurate measurement of the mean rate of flow by means of tubes, orifice plates and Venturi tubes in pipes where pulsations are present. Gives practical criteria for ensuring that flow pulsations are damped to such an extent that systematic errors in the indicated time-mean flow rate do not exceed a specified value. Also describes how uncertainty in the measurement of mean flow rate under pulsating flow conditions can be established. Also includes definitions, symbols and indices, annexes and diagrams.