International comparison of gauge blocks up to 100 m long between Latin American countries, Spain and Germany

The paper presents the results of an international intercomparison of gauge blocks up to 100 mm in length, which was carried out in 1994/95 between twelve metrological laboratories in seven Latin American countries, Spain and Germany and evaluated in 1996 on the occasion of a workshop in Brazil. Three identical sets of five selected gauge blocks of different lengths and calibration degree K were circulated between groups of 3 and 4 laboratories. Before and after each cycle, all gauge blocks were mechanically calibrated in the pilot laboratory ''Centro Espanol de Metrologia (GEM)'' in Madrid. Initial calibration was carried out in the PTB's laboratory for interferential length measurements, which acted as the reference laboratory. In the cours of the intercomparison, the central length and the deviations from the central length were determined. On the whole, the results show good agreement with the PTB's reference values. In this contribution, the deviations of the results obtained by the individual laboratories are analyzed. The results were discussed and evaluated at this workshop organized for all those who participated in the measurements. This enabled the metrology institutes of Latin America to assess the technical competence of their laboratories in the field of gauge block calibration. CEM cooperated as rite coordinator in the intercomparison which was initiated by the PTB's ''Technical Cooperation'' department and financed by the Federal Ministry for Economic Cooperation and Development (BMZ) within the scope of a supraregional project.