---
metadata:
  title: CIPM, 1989
  date: '1989-01-01'
  source: BIPM - Pavillon de Breteuil
resolutions:
- dates:
  - '1989-01-01'
  title: The International Temperature Scale of 1990
  identifier: 5
  url: https://www.bipm.org/en/CIPM/db/1989/5/
  approvals:
  - type: affirmative
    degree: unanimous
    message: |-
      +

      The Comité International des Poids et Mesures (CIPM)
  considerations:
  - type: recognizing
    date_effective: '1989-01-01'
    message: |-
      acting in accordance with cgpm-resolution:en/18/7[Resolution 7] of the 18th Conférence Générale des Poids et Mesures (1987) has adopted the International Temperature Scale of 1990 ( https://www.bipm.org/en/publications/its-90.html[ITS-90]) to supersede the International Practical Temperature Scale of 1968 (IPTS-68).

      The CIPM *notes* that, by comparison with the IPTS-68, the ITS-90

      * extends to lower temperatures, down to stem:[0.65 "K"], and hence also supersedes the EPT-76,
      * is in substantially better agreement with corresponding thermodynamic temperatures,
      * has much improved continuity, precision and reproducibility throughout its range and
      * has subranges and alternative definitions in certain ranges which greatly facilitate its use.

      The CIPM also *notes* that, to accompany the text of the ITS-90 there will be two further documents, the _Supplementary Information for the ITS-90_ and _Techniques for Approximating the ITS-90_. These documents will be published by the BIPM and periodically updated.

      The CIPM *recommends*

      * that on 1 January 1990 the ITS-90 come into force and
      * that from this same date the IPTS-68 and the EPT-76 be abrogated.
  actions: []