EURAMET 1125. Evaluation of cross-float measurements with pressure balances

The calibration of a pressure balance involves determining the values of A0 and the pressure distortion coefficient  that define the effective area Ae of the piston-cylinder assembly as a function of pressure. Various approaches are possible be to determine and estimate the uncertainties of these parameters, with results that may differ significantly. The purpose of EURAMET project 1125, led by LNE, is to verify numerically the performance of different methods used by the NMI’s by applying simulated data sets. Starting from simulated data prepared by LNE, INRIM calculated the values of the effective area values including the evaluation of their uncertainties by using a linear lest square method. Finally effective area at atmospheric pressure and reference temperature Ao and elastic distortion coefficient  were also calculated. The report describes the calculation method and the results obtained.