The Basis of Temperature Measurement

Abstract

Measurement activity in the UK is estimated to cost about £18,000 million per annum, and yet the principles which underlie measurement processes are frequently ignored or misunderstood. In the case of temperature, one of the four or five most important parameters in industrial process control, the difficulties are compounded by the obscure nature of the quantity that is being measured. Starting with the definition of the unit, this article outlines how the temperature scale is built up and how the standards are established which form the basis of temperature measurement in the UK and internationally. Progress with improvements for the future, including the revision of the International Practical Temperature Scale, are discussed.