Results of an international comparison of water triple-point cells

Abstract

The reference temperatures of a large number of triple point of water cells collected from manufacturing sources around the world have been compared at the BIPM and in twelve national laboratories. This allowed an assessment to be made of the reproducibility of the realizations of the triple point of water and the equivalence of the experimental procedures. The results show that, in most cases, the temperatures of the cells agree to within ± 0,1 mK. In some cases, however, much larger differences and temperature changes were observed, for which no obvious explanation has so far been found. The results also provide a comparison of a large number of national reference cells.

Accurate experimental determination of the isotope effects on the triple point temperature of water. I. Dependence on the2H abundance

“…To assess the uncertainties in the realization of the TPW, international comparisons of cells were carried out among various metrology laboratories. One such international comparison, organized by the BIPM (Bureau International des Poids et Measures, Paris), carried out between 1994 and 1996 [2] Metrologia Accurate experimental determination of the isotope effects on the triple point temperature of water. I.…”

Étalons métrologiques fondamentaux

“…Dans certaines conditions expérimentales, il est possible d'obtenir à l'intérieur de la cellule thermométrique un équilibre thermodynamique des trois phases solide-liquide-vapeur. Le point triple ainsi obtenu présente une reproductibilité de l'ordre de 50 μK (incertitude élargie pour k = 2) [66]. La valeur de 273,16 K est assignée à la température de ce point triple.…”

Interlaboratory comparison of realizations of the triple point of water

“…During this period cell No. 673 was compared with IMGC, KRISS and VNIIM cells as part of the BIPM interlaboratory comparison of the triple point of water [7].…”