PD ISO/TR 20461:2000

This Technical Report gives the detailed evaluation of uncertainty for volume measurements according to the Guide to the Expression of Uncertainty in Measurement (GUM) [1]. It uses the gravimetric method specified in ISO8655-6[2] as the reference method for calibrating piston-operated volumetric apparatus. It has been arranged in paragraphs to facilitate direct access to different aspects of this kind of evaluation as follows:

• modelling the measurement by describing the physical equations necessary to calculate the volume using the gravimetric method of measurement;

• determination of the standard uncertainty of measurement associated with the volume V₂₀ by describing the calculation procedure according to the GUM;

• determination of the sensitivity coefficients with an example of the calculation of all sensitivity coefficients by using complete equations, approximations of equations and by giving numerical values for standard conditions;

• determination of the standard uncertainty associated with the volume delivered by a piston-operated volumetric apparatus giving the combination of the standard uncertainty associated with the volume V₂₀ measured using the gravimetric measuring system and the experimental standard deviation associated with the volume delivered by the apparatus;

• determination of the standard uncertainties of measurement with a brief insight into the calculation of uncertainties of measuring devices according to GUM;

• determination of the expanded uncertainty of measurement associated with volume V₂₀;

• example of the determination of the uncertainty for volume measurements.