Everything About NDIR Sensors

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A non-dispersive infrared sensor (NDIR) serves as a gas sensor to detect and quantify gases in the atmosphere, along with their concentrations. NDIR sensors work on the principle of molecules absorbing specific wavelengths of infrared light. Air samples are collected in a tube and then analyzed under a light source.

NDIR sensors are known for their exceptional precision and sensitivity, making them suitable for a wide range of scenarios where monitoring gases and their concentrations is critical.

These applications include industrial safety, environmental monitoring and medical applications. This article provides an overview of NDIR sensors, outlines their benefits, and explores practical applications.

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Working principle of NDIR sensors

NDIR sensors are mainly used to measure carbon dioxide, carbon monoxide, methane and sulfur dioxide.

These gases can pose serious risks at high concentrations, making monitoring in different environments necessary. Gas sensors, like NDIRs, consist of a sample chamber, an infrared detector, and an infrared light source.

The sample chamber is located between the light source and the detector and contains the gas sample intended for analysis. The light source emits infrared light through the sample chamber, while the detector quantifies the amount of light that successfully passes through.

Gas molecules interact with infrared radiation, and the energy ratio between radiation and incidents depends on the gas concentration. Gas sensors measure gas concentration by monitoring the reduction in emitted infrared light.

Applications of NDIR sensors

NDIR sensors are used in virtually every industry and meet a broad spectrum of monitoring needs. They are used in breathalyzers to determine blood alcohol levels, detect refrigerant leaks and monitor toxic gases in hazardous environments. This section sheds light on the environmental, industrial, and medical applications of NDIR sensors.1

Environmental Control

Gas monitoring is essential in many environmental situations and includes monitoring emissions from industrial processes, measuring indoor air quality and assessing gas concentrations in ambient air.

The exceptional sensitivity and precision of NDIR sensors make them an ideal choice. However, moisture and temperature fluctuations can affect performance, requiring adjustments.

Industrial applications

In industrial environments, NDIR sensors play a crucial role in ensuring the safety of personnel and environments by effectively detecting toxic or explosive gases. Particularly in production facilities, they offer a cost-effective and reliable solution that increases employee safety.

Medical applications

Hospitals use infrared sensors to monitor gas concentration levels in anesthesia machines, ensuring patient safety during surgical procedures.

Benefits of NDIR sensors

Numerous benefits come with the use of NDIR sensors in gas monitoring applications. They provide a low-maintenance solution with long-lasting performance. Additional benefits include:

  • Cost efficient
  • High accuracy and sensitivity
  • High selectivity to target gases
  • Monitor a range of gases

Although NDIR sensors may require a higher initial investment, their benefits translate into lower overall costs as they provide accurate and reliable gas monitoring over longer periods of time. As technology advances, NDIR sensors will continue to evolve for more advanced monitoring applications.

Dexter Research Center

The Dexter Research Center offers a comprehensive selection of infrared gas and temperature detectors that deliver reliable and stable performance over the long term.

The products have been used in environmental and industrial monitoring, hospital anesthesia monitoring and even NASA space missions. The company remains committed to developing high-quality, reliable devices for customers around the world.

References and further reading


This information was obtained, reviewed and adapted from materials provided by Dexter Research Center, Inc.

For more information about this resource, please contact Dexter Research Center, Inc.

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