Final report on COOMET key comparison of national pressure standards in the range 100 Pa to 5 kPa of gauge pressure (COOMET.M.P-K14)

This report describes a COOMET key comparison of pneumatic gauge pressure standards of four national metrology institutes (listed in the chronological order of their measurements) that was carried out in the period from November 2008 to March 2010 in order to determine their degrees of equivalence in the range of 100 Pa to 5 kPa of gauge pressure. The pilot laboratory was PTB. The reference pressure standards of the participants were of different design. The transfer standard was a piston gauge model V1600 of the company Pressurements. The quantity under comparison was the effective area of the transfer standard at different pressure values reported together with uncertainty contributions and the conclusive combined uncertainty of measurement. All participants' results agree with the key comparison reference values within the expanded uncertainties calculated with a coverage factor 2, all but one results even within the standard uncertainties. For the participants' results compared in pairs, all of a total of 48 pairs show agreement within the expanded uncertainties and 46 pairs within the standard uncertainties. The results of the comparison demonstrate equivalence of the laboratory standards and support their measurement capabilities stated in the KCDB of BIPM.