An NDIR (NonDispersive InfraRed) sensor has a detector that measures how much infrared light of specific wavelength that is absorbed by the surrounding air. This measurement is then used to calculate the concentration of a specific gas.

Compared to electrochemical sensors, the lifetime of the NDIR sensors is very long. This is mostly due to the fact that these sensors have no sensor burn-out nor any sensor deterioration upon exposure to gases. Further-on, the interference from other gases in the measurements is minimal to zero for NDIR sensors, depending on which gas that is to be measured.

When it comes to semiconductor sensors, they perform best in higher concentrations (2 000 – 10 000 ppm) and are cross-sensitive to humidity and temperature fluctuations. The semiconductor sensors can also deteriorate as non-target gases may absorb on the oxide surface.

For the gases where NDIR sensors can measure the concentration, they have none of these problems and works well for all concentrations of the target gas. All in all, the major advantages with NDIR sensors are low life cycle cost and a precise and stable long-term operation.

All sensors drift over time, which means that recalibration is needed for long-term accuracy.

 With SenseAir’s automatic baseline correction the drift in our NDIR sensors is automatically corrected in normal indoor applications, which eliminates the need to manually recalibrate the sensors. In the end, this gives a maintenance-free sensor that has a life expectancy with maintained accuracy of at least 15 years.