What concentration causes a carbon monoxide detector to alarm?
1, General setting
Carbon monoxide detectors usually have two levels of alarm values, namely the first level alarm value and the second level alarm value. The specific settings of these two values may vary depending on the instrument model and usage scenario.
The common setting range for the first level alarm value is between 10ppm and 50ppm. Some suggested settings include 10ppm, 25ppm, and 30ppm. When the concentration of carbon monoxide in the air reaches or exceeds this value, the detector will emit a low-frequency sound and light alarm signal to remind people to pay attention to ventilation and prevent further increase in carbon monoxide concentration.
The common setting range for the second level alarm value is between 50ppm and 300ppm, and there are also cases where it is set to 150ppm to 300ppm or 200ppm to 500ppm. When the concentration of carbon monoxide in the air reaches or exceeds this value, the detector will emit a high-frequency sound and light alarm signal, warning people that immediate measures must be taken, such as rapid evacuation, to avoid poisoning accidents.
2, Special settings
In some special cases, the alarm concentration value of the carbon monoxide detector may need to be specially set. For example, being in a closed indoor environment for a long time may gradually increase the concentration of carbon monoxide indoors, so it may be necessary to adjust the alarm concentration value lower in order to issue an alarm in a timely manner.
Places with a large number of emission sources, such as industrial production lines and near combustion equipment, also need to adjust the alarm concentration value lower due to the high amount of carbon monoxide emissions to ensure safety.
3, Regional standards
Different countries and regions may have different regulations and standards for setting the alarm concentration value of carbon monoxide detectors.
In China, according to the "GBZ2.1-2019 Occupational Exposure Limits for Hazardous Factors in the Workplace", the PC-TWA (time weighted average concentration) value of carbon monoxide is 20mg/m ³ (approximately 17ppm), and the PC-STEL (short-term exposure average concentration) value is 30mg/m ³ (approximately 26ppm).
In practical applications, some documents recommend setting two levels of alarms for carbon monoxide detectors, with a first level alarm value of 25ppm and a second level alarm value of 50ppm.
At the same time, it is also recommended to set the alarm of the portable carbon monoxide detector to 10ppm for the first level and 25ppm for the second level. In Europe, some countries set the concentration threshold for carbon monoxide detectors at 200ppm to 500ppm.
