This report describes a CCM key comparison of low differential-pressure standards at four Mational Metrology Institutes (NMIs) that was carried out during the period July 1998 to May 1999 in order to determine their degrees of equivalence at pressures in the range 1 Pa to 1000 Pa. The differential pressures were superimposed on a line pressure of nominally 100 kPa. The primary standards, which represent two principal measurement methods, included three liquid-column manometers and one double pressure balance. The transfer standard package consisted of four high-precision pressure transducers; two capacitance diaphragm gauges to provide high resolution at low differential pressures, and two resonant silicon gauges to provide the required calibration stability. Two nominally identical transfer packages were used to reduce the time required for the measurements, with Package A being circulated among laboratories in the European region (IMGC and NPL-UK) and Package B being circulated through the Asia-Pacific region (MSL-NZ). The results obtained with different transfer packages were normalized by using data obtained from simultaneous calibrations of the two packages at the pilot laboratory (NIST). The degree of equivalence of the measurement standards were determined in two ways, deviations from key comparison reference values and pairwise differences between these deviations. The differential-pressure standards of the four participating NMIs were generally found to be equivalent and the results revealed no significant relative bias between the two principal methods tested by the comparison.
Final Report on Key Comparison CCM.P-K5 in Differential Pressure from 1 Pa to 1000 Pa
2002
Abstract
This report describes a CCM key comparison of low differential-pressure standards at four Mational Metrology Institutes (NMIs) that was carried out during the period July 1998 to May 1999 in order to determine their degrees of equivalence at pressures in the range 1 Pa to 1000 Pa. The differential pressures were superimposed on a line pressure of nominally 100 kPa. The primary standards, which represent two principal measurement methods, included three liquid-column manometers and one double pressure balance. The transfer standard package consisted of four high-precision pressure transducers; two capacitance diaphragm gauges to provide high resolution at low differential pressures, and two resonant silicon gauges to provide the required calibration stability. Two nominally identical transfer packages were used to reduce the time required for the measurements, with Package A being circulated among laboratories in the European region (IMGC and NPL-UK) and Package B being circulated through the Asia-Pacific region (MSL-NZ). The results obtained with different transfer packages were normalized by using data obtained from simultaneous calibrations of the two packages at the pilot laboratory (NIST). The degree of equivalence of the measurement standards were determined in two ways, deviations from key comparison reference values and pairwise differences between these deviations. The differential-pressure standards of the four participating NMIs were generally found to be equivalent and the results revealed no significant relative bias between the two principal methods tested by the comparison.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
