Describes methods of assessing the uncertainty in the calibration of any method of measuring flow-rate, either in closed conduits or in open channels. Deals with the estimation of the uncertainty in one or more measurements which use the resulting calibration graph. Applicable only if the variables may be transformed to create a linear relationship between them, the range over which the relationship is established may be subdivided in such a way that one variable varies linearly with the other within each subdivision, or systematic deviations from linearity of the calibration graph are negligible in comparison with the uncertainty associated with the individual points forming the graph.

BS ISO TR 7066-1 : 1997