National Standard for Temperature Measurement (in range -38,8344 °C to 961,78 °C)

The temperature standard realizes the fundamental unit of the SI system – kelvin (K). The National Standard for Temperature ensures the temperature scale in accordance with the international ITS-90 document.

Implementation of the Temperature Scale

The temperature scale in compliance with ITS-90 is defined using standard platinum resistance temperature sensors (SPRTs) calibrated at specific defining fixed points and corresponding interpolation equations.

The temperature scale at the Slovak Institute of Metrology (SMÚ) is realized using the following equipment:

Defining Fixed Points

• Triple point of argon: -189.3442 °C
• Triple point of mercury: -38.8344 °C
• Triple point of water: 0.01 °C
• Melting point of gallium: 29.7646 °C
• Freezing points of metals:
  • Tin (Sn): 231.928 °C
  • Zinc (Zn): 419.527 °C
  • Aluminum (Al): 660.323 °C
  • Silver (Ag): 961.78 °C
  • Copper (Cu): 1084.62 °C

Measurement and Calibration Equipment

• Standard platinum resistance temperature sensors (SPRTs)
• High-temperature platinum resistance thermometers
• Furnaces and liquid baths for realizing the defining fixed points
• Temperature sensing and evaluation devices (multimeters, AC resistance bridges, etc.)
• Auxiliary equipment (resistance standards, liquid baths for stabilizing resistance standards)

 

Documents for download

• Osvedčenie (certifikát) (pdf, 1.1 MB)