NDIR Gas Sensors

NDIR gas sensors measure target gas concentration through infrared light absorption. They project IR light through a sample gas volume. The detector then measures intensity reduction at the gas’s characteristic absorption wavelength. This principle is continuous, non-consumptive, and highly selective. Furthermore, it avoids poisoning, drift, and cross-sensitivity issues common in catalytic bead and electrochemical sensors.

Each gas absorbs IR radiation at a specific wavelength. CO2 absorbs at 4.26 µm. CO absorbs at 4.67 µm. Methane absorbs at 3.3 µm. N2O absorbs at 4.5 µm. SO2 absorbs at 7.3 µm. Bandpass filters isolate each target wavelength at the detector. They reject signals from all other gases simultaneously. Additionally, dual-wavelength reference designs add a second detector at a non-absorbing wavelength. This ratio cancels source aging, temperature drift, and optical fouling. As a result, sensors maintain calibration accuracy across 5 to 10 year service intervals.

OEM NDIR modules integrate into fixed detectors, portable analyzers, and HVAC controllers. They connect through 4–20mA, RS-232, and I2C interfaces. The Senseair S8 and Sensirion SCD40 consume under 35mW. These suit battery-powered IoT air quality devices and ventilation systems. Moreover, industrial NDIR sensor heads in ATEX and IECEx certified housings carry Zone 1 and Zone 2 ratings. Open-path NDIR pairs project detection beams across 5 to 200 meters. They cover large process areas with fewer sensor points than fixed-point arrays require.

Sensor service life reaches 5 to 10 years. This reduces replacement and maintenance costs across large installations significantly.

These sensors serve Pakistan’s SSGC and SNGPL gas networks, OGDCL processing facilities, WAPDA power stations, pharmaceutical cleanrooms, hospital anaesthesia systems, and building HVAC installations across Karachi, Lahore, and Islamabad.

Tactical Supply Pakistan supplies NDIR gas sensors for industrial safety monitoring, HVAC control, process gas analysis, and environmental compliance procurement across Pakistan.