How does Testo determine CO2 content in the air?
What method does Testo actually use for CO2 measurement?
The measuring technology used by Testo is based on the NDIR (non-dispersive infrared) absorption principle.
This measuring principle involves the electro-optical measurement of the concentration of the gas being searched for via the extent of absorption of a specific wavelength.
The sequence is as follows:
- The light bulb emits radiation.
- The CO2 absorbs radiation at λ=4.27 μm.
- High CO2 concentration - high radiation absorption.
- The filter only lets radiation through with λ=4.27 μm.
- The radiation on the detector is a measure of the CO2 concentration.
The advantages of this measuring principle:
- No cross sensitivity with respect to other gases.
- No wear of the sensor, which means a long service life.
- If the incidence of gas is too high, this does not lead to contamination of the sensor.