Alberta Boilers Safety Association (ABSA) Practice Test

NDIR (Non-Dispersive Infrared) detectors are specifically designed to measure gases that absorb infrared light, making them highly effective for detecting carbon dioxide (CO2) and carbon monoxide (CO). The principle behind NDIR technology involves the absorption of infrared radiation at specific wavelengths associated with these gases. When the concentration of the target gas increases, more infrared light is absorbed, resulting in a measurable change that can be correlated to gas concentration.

This technology is particularly advantageous for monitoring ambient air quality in various environments, including industrial and combustion processes, where CO and CO2 levels can fluctuate significantly. The precision of NDIR detectors allows for accurate readings, which is essential for safety and regulatory compliance in handling combustion gases.

The other options, while relevant to air quality and combustion sources, do not align with the primary focus of NDIR detectors. For instance, SO2 and NOx are not primarily measured by NDIR technology as they do not exhibit the same infrared absorption characteristics. Relative humidity is a separate measure that involves different sensing technology entirely, such as capacitive or resistive sensors, rather than infrared detection.