Why do combustible gas detectors have a much larger service radius than toxic gas detectors?
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Why do combustible gas detectors have a much larger service radius than toxic gas detectors? Is it meaningful to set the alarm threshold of a combustible gas detector according to that of toxic gases?
Flammable gas detectors measure the calorific value of C-H chains; they are used to detect mixtures. The principle behind these detectors is mostly based on catalytic combustion, with some using semiconductor technology and others employing infrared principles； Toxicity detectors have good selectivity; for specific gases such as carbon monoxide and hydrogen sulfide, they are generally electrochemical sensors
Oh(⊙o⊙) Oh, I’ve learned it!
The alarm threshold values for combustible gas detectors and toxic gases are different; they cannot be set the same.
So for many organic compounds that are both toxic and flammable, by installing a flammable gas alarm and setting the alarm threshold according to the toxicity levels, a broad range of protective effects can be achieved. So I still can’t fully understand what Your Excellency is saying.
If it is both toxic and flammable, it seems to be classified as toxic. I heard someone say that, but I’m not sure;P
According to the toxic settings, it is clearly specified in the regulations.
Of course it makes no sense; for toxic gases, the concentration detected is very low, usually on the ppm scale. The range for combustible gases is generally their minimum explosive limit; for example, the range of 0~100% for methane corresponds to concentrations of 0~5%. Let’s use a pressure gauge as an example. Tell me, since the media being measured are the same, can a pressure gauge with a capacity of 16 MPa be used to measure a pressure of 0.8 MPa? No, you need to use a gauge with a pressure range of 1.6 MPa, right? Accuracy is an important requirement when selecting such a gauge.
You can be sure that the regulations are in bold, as they are mandatory provisions.
There are guidelines for this; you can figure it out by looking at the guidelines. If you want to use it for detecting flammable gases, the alarm thresholds for toxic gases won’t work, as flammable gases are measured in LEL units, which are essentially on a vol% scale. In contrast, the alarm thresholds for toxic gases are expressed in ppm levels; 1% vol% equals 10,000 ppm, and the precision required for measuring flammable gases simply cannot achieve that level. For example (without looking up the specific values), for hydrogen, as a flammable gas, the range is 0-100% LEL, which corresponds to 0-4% vol; as a toxic gas, an alarm is triggered at 50 ppm, which is equivalent to 0.005% vol. Is this alarm value acceptable?