Today, temperature measurement is essential across all industries. For the most common temperature measurements, a widely used temperature scale has been developed, known as the “International Temperature Scale” (ITS-90). This scale covers a temperature range from –259.34 °C to +1064.43 °C. Its definition is based on a number of fixed-point temperature phenomena such as: – the triple point, – the boiling point, – the freezing point of certain materials. In practice, the ITS 90 can be closely compared to the fundamental thermodynamic temperature scale. The units of measurement on the scale are expressed in KELVIN, but they are more commonly expressed in CELSIUS.
