Final report on key comparison EUROMET.M.P-K3.a in the gauge pressure range 50 kPa to 1000 kPa

The standards of 7 European Laboratories in the pressure range from 100 to 1000 kPa, with an option at 50 kPa, have been compared in the period 2000 - 2001. The transfer standard was a pressure balance equipped with a gas-lubricated piston-cylinder assembly of nominal effective area 980 mm². This assembly was formerly used as transfer standard for the key comparison CCM.P-K1.b. At the time of the comparison, the results relating to the effective area were not published. The link of the EUROMET.M.P-K3a comparison to CCM.P-K1.b will be established through the results of LNE, acting as the pilot laboratory. The comparison protocol for the EUROMET comparison was the same as for the CCM one. As the difference between the CCM reference value and the EUROMET reference value was not significant, the CCM reference value has been used to establish the equivalence statements of the participants to the EUROMET.M.P-K3a comparison to CCM.P -K1.b. The deviations from the reference value of all the laboratories but one are less than their estimated expanded uncertainty. Over 21 combinations of pairs of European laboratories, 18 demonstrate equivalence of the results at 1 MPa.