GULFMET M.M-S1: Comparison of mass standards in multiples and sub-multiples of the kilogram

In order to show metrological equivalence in mass standards calibration among National Metrology Institutes (NMIs) of member countries of the "Gulf Association for Metrology" (GULFMET), the first organized supplementary comparison (SC) of mass standards have been carried out under the auspices of the GULFMET. This supplementary comparison of 10 kg, 500 g, 20 g, 2 g and 100 mg stainless steel mass standards was based on the decision of the GULFMET meeting held in 2013. TUBITAK-UME (Turkey) acted as pilot laboratory. In this region only two NMIs have the CIPM-MRA signature. These NMIs are SASO-NMCC (Saudi Arabia) and EMI (Abu Dhabi). Therefore, the reference values were calculated with the weighted mean method using these two participating laboratories. Concerning the weight of 100 mg, the weight has not been evaluated in this comparison because the travelling standard was mixed-up at some point during the artefact circulation. The results of EMI and SASO-NMCC are consistent with the reference values within their expanded uncertainties with the coverage factor, k = 2.