Why is it not recommended to use exhalation, lighters, alcohol test detector response?
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Some gas sensors, like ammonia, have a tiny cross-over response to carbon dioxide.In a normal atmosphere, co2 is only 0.03% (0.03% = 300ppm), so you don't have to worry about the effects of co2 when using it under normal circumstances.The concentration of carbon dioxide in human breath is as high as 4% (4% = 40000ppm), it will affect the normal operation of the sensor under so high concentration.In addition, people with bad breath also exhale a lot of hydrogen sulfide, ammonia, sulfur dioxide, nitrogen dioxide and other gases.Therefore, it is not recommended to randomly test the alarm with human breath.
Some customers feedback that there was no response to the gas alarm test after lighting with a lighter.Weather there is a response depend on specific operations such as angle, distance etc.If there is a response, it should be the reason of large amount of carbon dioxide and carbon monoxide produced during combustion.The situation of lighter combustion is very complicated. In addition to high concentration of carbon dioxide, it may also produce SO2, NO2, etc., as well as methane, carbon monoxide and other gases produced by incomplete combustion. Therefore, it is impossible to predict the response of the sensor.In addition, if you get too close, the heat from the combustion might damage the sensor.So it is not recommended to test the alarm with a lighter.
When the liquid alcohol volatilizes, the regional concentration can be up to tens of thousands of PPM, which may damage the sensor.So we should avoid using alcohol to test an alarm or using alcohol to subs an alarm and a sensor.
Science:
In the process of human respiration, the composition and proportion of inhaled gas are the same as that of air, with nitrogen accounting for 78% and oxygen for 21%.
Rare gas is 0.94%, carbon dioxide is 0.03%, water vapor, other gases and impurities are 0.03%.In the process of breathing, the composition of the gas exhaled changes, nitrogen is still about 78%, oxygen dropped to about 16%, dioxygen,and carbon dioxide rises to about 4 %, and water vapor content increased significantly.