Journal of Research of the National Bureau of Standards Section A Physics and Chemistry · 1961 · 119 citations · 0 references
EngineeringEarth SciencesHeat TransferMetrologyScale DevelopmentMeasurement StandardsScale RefinementStandard UnitsTemperature MeasurementTemperature MetrologyUnits Of MeasurementFixed-point Temperature StandardsMetric ScalesScale StandardizationStandard Units Of TemperatureTemperature ScalesTemperature ScalingTemperature StandardsTemperature Units
The International Practical Temperature Scale of 1948 is a revision of the 1948 scale that retains the same numerical values, is named by IUPAC, and is based on six fixed equilibrium temperatures with interpolation formulas, incorporating new information since 1948. The scale was updated to improve reproducibility by replacing the ice point with the triple point of water at 0.01 °C and recommending the zinc point at 419.505 °C instead of the sulfur point.
The International Practical Temperature Scale of 1948 is a text revision of the International Temperature Scale of 1948, the numerical values of temperatures remaining the same. The adjective "Practical" was added to the name by the International Committee on Weights and Measures. The scale continues to be based upon six fixed and reproducible equilibrium temperatures to which values have been assigned, and upon the same interpolation formulas relating temperatures to the indications of specified measuring instruments. Some changes have been made in the text to make the scale more reproducible than its predecessor. The triple point of water, with the value 0.01 °C replaces the former ice point as a defining fixed point of the scale. It is also recommended that the zinc point, with the value 419.505 °C, be used instead of the sulfur point. The recommendations include new information that has become available since 1948.