The detection standard value of a toxic and harmful gas detector is not a fixed figure, but is determined based on the specific type of gas being detected, the application scenario, and relevant safety standards.
The following are the 4 in 1 gas detector portable detection standard value ranges of some common harmful gases for your reference: In indoor environments, the safe concentration of carbon monoxide (CO) should generally not exceed 70ppm. The safe standard for hydrogen sulfide (H2S) in industrial environments is usually 10ppm. The upper limit of the safe concentration of ammonia (NH3) in normal air environments is 25ppm. As the main content of natural gas, the explosion limit of methane (CH4) is between 5%LEL and 15%LEL. Therefore, all concentrations within this range should be given high attention.
1. Carbon monoxide (CO) :
In indoor environments, its safe concentration should generally not exceed 70ppm(parts per million).
When the concentration reaches 150-200 PPM, the human body will experience headache, dizziness, nausea and may even lead to coma.
Once the concentration exceeds 400ppm, it may be fatal.
2. Hydrogen sulfide (H2S) :
The safety standard in an industrial environment is usually 10ppm.
Hydrogen sulfide is a colorless and toxic gas with a smell of rotten eggs. However, when its concentration is too high, it may instead cause people to lose their sense of smell, thus making them overlook its danger.
3. Sulfur dioxide (SO2) :
In outdoor environments, the daily average concentration of sulfur dioxide generally should not exceed 0.15mg/m³; otherwise, it will have negative impacts on plant and human health.
4. Ammonia (NH ₃) :
Generally, the upper limit of the safe concentration of ammonia is 25ppm.
Ammonia has a strong pungent smell, but long-term exposure or when the concentration is too high may cause damage to the eyes, skin and respiratory tract.
5.Methane (CH4) :
As the main content of natural gas, its explosion limit is usually between 5%LEL and 15%LEL. Therefore, the concentration within this range should be given high attention.
In addition, for toxic and harmful gas detectors, alarm values are usually set as well. For example:
First alarm setting value : It should be less than or equal to 100%OEL(occupational exposure limit), or not more than 5%IDLH(concentration immediately threatening life and health) depending on the circumstances.
Second alarm setting value : shall be less than or equal to 200%OEL, or not more than 10%IDLH depending on the circumstances.