NMI – Calibration of pressure measurement #SWI2006
In pressure measurement the value of pressure is determined by dividing the force
exterted on a piston by the effective area of the piston. The effective area of the piston
may differ from the actual area because of irregularities at the piston edge and because of
leakage through the thin cavity between the piston and the enclosing cylinder. The
associated uncertainties constitute the largest contribution to the overall pressure
The various metrological institutes each use a different method of calculation of the
effective piston area for a given piston-cylinder combination. The figure below shows the
results of a comparison study in which six sets of measurement data were given to each
of the six participating institutes (taken from doi:10.1088/0026-1394/42/6/S11).
The details of these methods of calculation can also be found in same reference.
The question for the Study Group Mathematics with Industry 2006 is
Can we compare the different methods of calculation? Which is best?
Can they be improved any further?