In many types of industrial environments, workers spend much time in confined spaces and other areas where toxic gas buildups can occur. Therefore, facilities spend much time and money investing in detection systems to keep employees and equipment as safe as possible. However, when selecting a detection system for this purpose, LEL sensors may not be the best choice. Depending on a number of factors, particularly those pertaining to environmental conditions within the workplace, a Lower Explosive Limit meter may have difficulty in registering accurate toxicity readings. If your facility needs an accurate and reliable gas toxicity detection system, here are some details regarding LEL systems to keep in mind.

High Temperatures and Humidity

Though an LEL gas leak detector is designed to generally work well in harsh work environments, including those where high temperatures and humidity levels exist, certain issues can still make it difficult for these systems to record accurate toxicity readings. Since most LEL detectors contain wire elements linked to catalytic bead sensors, the heat and humidity can cause certain changes within the wire elements. When this happens, bead temperatures increase, resulting in gas concentration readings that may not be accurate.

Thermal Conductivity

In many situations where these sensors transmit inaccurate toxicity readings, it is due to thermal conductivity. On rare occasions, two elements within these sensors may have equal resistance. When this occurs, each element will change at an equal rate, which translates to the meter registering zero. Because this can happen so rarely, more research is being conducted on this topic to help find solutions to this occurrence.

Signal Abnormalities

Due to the many atmospheric changes that can lead to problems with LEL detection systems registering accurate toxicity readings, signal abnormalities between sensors is a more common occurrence. In these situations, the sensors may not register accurate toxicity readings, but will likely still register accurate readings regarding upper and lower explosive limits. In circumstances where signal abnormalities occur, elements within the sensors have equal resistance, leading to a condition known as zero drift. In these instances, the elements can register positive or negative readings, depending upon how much resistance each element within a sensor experiences.

Software Algorithms

Due to the many problems LEL monitors experience in measuring toxicity, engineers have been busy trying to come up with innovative solutions to this issue. One of the most promising in recent years has been the development of software filtering algorithms, which are now being used in more and more electronics found in LEL detection systems. By using this state-of-the-art software, drift in the sensors can be virtually eliminated. By doing so, this also makes the sensors much more accurate in work settings where high temperatures and humidity levels are present, opening them up for use by more and more facilities.

As engineers continue to examine new ways to solve this problem, LEL detection systems will continue to be vital to many industrial safety programs. To learn more about these systems, contact GDS at or call 409-927-2980.

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