Temperature and Humidity


The Temperature & Humidity Laboratory develops, maintains and disseminates the temperature and humidity national measurement standards in Singapore.

Temperature Fixed Point Standard

Temperature fixed point standards are used for the realisation of the International Temperature Scale of 1990 (ITS-90) from -189 °C to 961 °C at expanded uncertainties (k = 2) from 1 mK to 8 mK.

Qualified standard platinum resistance thermometers (SPRTs) can be calibrated according to ITS-90 definition.


Temperature fixed point standards


Standard platinum resistance thermometer

Mini Temperature Fixed Point Standard

  • Mini temperature fixed point standards are used for the calibration of nobel metal reference standard thermocouple from 156 °C to 1084 °C at expanded uncertainties (k = 2) from 0.05 °C to 0.5 °C.


Mini temperature fixed point cells


Reference standard thermocouple

Standard Radiation Thermometer

The primary standard radiation thermometer is used for realising the ITS-90 above the silver point temperature (961.78 °C) according to ITS-90 definition.

Typical calibration uncertainties (k = 2) of radiation thermometers from the silver point temperature to 2000 °C are from 1 °C to a few degree Celsius.


Fixed point blackbodies and primary standard radiation thermometer


Radiation thermometers

Transfer Standard Radiation Thermometer
  • The transfer standard radiation thermometer approximates the ITS-90 below the silver point temperature, using a set of fixed points together with an interpolation equation.
  • Typical calibration uncertainties (k = 2) of radiation thermometers from -30 °C to the silver point temperature are from a few tenth of degree Celsius to a few degree Celsius.


Fixed point blackbodies and transfer standard radiation thermometer

Standard Humidity Generator

The two-pressure humidity generator covers the relative humidity from 12 % to 95 % relative humidity at temperature range from 0 °C to 70 °C. It is suitable to calibrate relative humidity hygrometers at expanded uncertainty (k = 2) better than 2% relative humidity.


Calibration of a hygrometer using the Standard Humidity Generator


Hygrometer

Standard Low Humidity Generator

  • The two-pressure two-temperature low humidity generator covers the frost/dew point range from -75 °C to +10°C dew point. It is used for calibrating dew point meters at calibration uncertainties (k = 2) from 0.13 °C to 0.28 °C dew point.


Standard low humidity generator


Dew point meter