Resolution 7 of the 18th CGPM (1987)

Development of a new international temperature scale

The 18th Conférence Générale des Poids et Mesures


  • that world-wide uniformity and long-term stability of temperature measurements are of major importance for science, commerce and industry from both the technical and economic points of view,
  • that the value of a temperature on the practical scale must correspond closely to the value of the thermodynamic temperature in the SI,
  • that the 15th Conférence Générale des Poids et Mesures, taking cognizance of the differences that have been demonstrated between values of temperature on the International Practical Temperature Scale of 1968 (IPTS-68) and the corresponding values of thermodynamic temperature, has instructed the Comité International des Poids et Mesures to establish a new, substantially more accurate scale,
  • that it will be possible to propose in 1989 a new scale for which any remaining departures from thermodynamic temperature will be inconsequential for many years to come,

invites the Comité International des Poids et Mesures and the national laboratories to complete the development of this new temperature scale and to fix a date for putting it into practice simultaneously in all countries; the values of the differences between this new scale and the IPTS-68 should be announced at least one year before the adoption of the new scale which could take place on January 1st 1990.

DOI : 10.59161/CGPM1987RES7E

The reader should note that the official version of this Resolution is the French text

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