Resolution 3 of the 19th CGPM (1991)

The International Temperature Scale of 1990 (ITS-90) and future work in thermometry

The 19th Conférence Générale des Poids et Mesures,

considering

• that worldwide uniformity and long-term stability in the measurement of temperature are of great importance for science, industry and commerce for both technical and economic reasons,
• that the international temperature scale should be as close as possible to thermodynamic temperature,

noting

• that the 18th Conférence Générale in its Resolution 7 had invited the Comité International des Poids et Mesures and national laboratories to prepare and adopt a new international scale to replace the International Practical Temperature Scale of 1968, by then known to differ significantly from thermodynamic temperatures,
• that the International Temperature Scale of 1990 (ITS-90) adopted by the Comité International in 1989 at its 78th Meeting is generally more precise, more readily realized and more nearly in accord with thermodynamic temperatures, and that it fulfills the requirements demanded of it by Resolution 7 of the 18th Conférence Générale,

recommends that national laboratories continue their efforts to improve the worldwide uniformity and long-term stability in the measurement of temperature by the rapid implementation of the ITS-90 and the maintenance of research programmes on fundamental thermometry.

DOI : 10.59161/CGPM1991RES3E