NDIR Gas Sensors: Are there any downsides to consider?

NDIR gas sensors were introduced in the 1960s and has been a staple of the gas detection industry for decades. These gas sensors work by detecting combustible gases at different wavelengths using infrared light. There are many advantages to using NDIR technology, but there are also some disadvantages that any user should consider.

NDIR gas sensors
NDIR Technology Overview

Prior to the development of NDIR gas sensors, catalytic bead sensors were primarily used for detecting gas leaks. NDIR gas sensors have many advantages over catalytic bead sensors. They are not susceptible to poisoning, do not burn out even when exposed to high concentrations of gases, and rarely require calibration. NDIR gas sensors also have a fail-safe so that inoperable sensors can be detected.

Additionally, they have a longer life than catalytic bead sensors and can even detect gases in low-oxygen environments. They are also inexpensive and require less power than catalytic bead sensors. Since NDIR technology addressed many of the limitations found with catalytic bead sensors, they were a giant leap forward for gas detection technology, especially when used for detecting methane.

NDIR Sensor
NDIR Sensors & Hydrocarbons

Despite the advantages they have over catalytic bead sensors, NDIR gas sensors are not without their limitations. Most notably, NDIR sensors cannot detect hydrogen because this gas does not absorb infrared light. Hydrogen is a potentially dangerous gas in many mining and petroleum extraction and processing environments.

NDIR sensors are incredibly accurate at detecting methane, but they do not work well when multiple hydrocarbon-based gases are present. In these situations, they are likely to provide false readings. Unfortunately, in many industries, detecting hydrogen and hydrocarbons is critical in maintaining a safe workplace. Hydrogen is commonly used in petroleum refining, treating metals, producing fertilizer, and processing foods.

And the hydrogen market is projected to grow to exceed $160 billion by 2026, meaning reliable detection methods for hydrogen will become increasingly important.

Hydrogen is a flammable and combustible gas frequently used in the same vicinity as other flammable materials and gases. It has lower ignition energy than gasoline or natural gas and once ignited, it can rapidly spread or lead to a severe fire or explosion. Hydrogen is simply a very dangerous gas. And when hydrogen is present, there is often a greater risk of exposure to other dangerous gases, such as butane and methane.

Exposure to even low concentrations of hydrogen can result in nausea, headaches, delirium, tremors, convulsions, and irritation of the skin and eyes. At higher concentrations, an individual can rapidly lose consciousness, and the effects of hydrogen on the central nervous system make it deadly in a short amount of time.

In order to protect the workplace, its workers, and the profitability of the business, employers in industries that use hydrogen and hydrocarbons need to have reliable and accurate gas sensors. NDIR sensors have a severe limitation due to their failure to detect hydrogen entirely, and that they often provide false readings in environments with mixed hydrocarbons.

gas Sensor
Other Limitations With NDIR Sensors

In addition to their inadequacies when encountering hydrocarbons, NDIR sensors are susceptible to moderate changes in the environment’s temperature and humidity, freezing their output during temperature transitions. They function poorly in extreme environments or where there is a rapid change in conditions.

The design of NDIR sensors also allows humidity, fog, and ambient infrared light into the open chamber, all of which can cause interference. This interference can impact their reliability, providing another opportunity for these sensors to fail and potentially expose workers to risk. NDIR sensors also typically require a great amount of power to function, and they require frequent calibration which contributes to a higher total cost of ownership.

And since NDIR is a proprietary technology, the sensors themselves can be quite expensive when purchased.

The limitations of NDIR sensors are great, and any potential user should understand the pitfalls of using these sensors before purchasing them. Recent advances in gas detection mean that more suitable products are available to help employers ensure their workplace remains safe and their assets are protected.

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