Pneumatic gauge pressure comparison measurements between the UME (Turkey) and the CMI (Czech Republic) - EUROMET Project No. 537

The results are presented of a bilateral comparison of pneumatic pressure measurements, carried out in the framework of EUROMET Project No. 537, between the Cesky Metrologicky Institut (CML Czech Republic) and the TUBITAK-Ulusal Metroloji Enstitusu (UME, Turkey). The measurements, in the range 15 kPa to 7 MPa, were carried out in two phases: (i) 18-24 June 1999 at the Pressure Section of the CMI in the range 15 kPa to 350 kPa; (ii) 29 June-8 July 1999 at the Pressure Section of the UME in the ranges 0.25 MPa to 1.75 MPa and I MPa to 7 MPa. Three different gas-operated reference standards were used. For the ranges 15 kPa to 350 kPa and 0.25 MPa to 1.75 MPa these were piston-cylinder assemblies with ceramic pistons and tungsten-carbide cylinders and nominal effective areas of 10 cm(2) and 2 cm(2), respectively. For the range I MPa to 7 MPa, a piston-cylinder assembly with tungsten-carbide piston and cylinder and a nominal effective area of 0.5 cm(2) was used. The purpose of the measurements was to compare the effective areas of the Czech and Turkish primary pressure standards in gas media and gauge mode, and to confirm the agreement between the pressure scales of the two countries in the range 15 kPa to 7 MPa by application of the cross-floating method. Since the UME and the CMI are participating in different loops of EUROMET Project No. 439, a key comparison of pneumatic pressure, another important goal of this study was to establish a cross-link between the two loops.