What are the commonly used units for gas detectors?
%VOL: refers to the concentration volume ratio of mixed gases, often used to detect carbon dioxide (CO2), oxygen (O2), nitrogen (N2), argon (Ar) and other gases.
%LEL: refers to the percentage of the lower explosion limit of flammable gas, which is the lowest concentration at which an explosion occurs when flammable gas is mixed with air and encounters minimum ignition energy. This unit is generally used for combustible gases. The combustible gas range is generally 0-100% LEL; common combustible gases include hydrogen (H2), carbon monoxide (CO), methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10), ethylene (C2H4 ), propylene (C3H6), butene (C4H8), acetylene (C2H2), propyne (C3H4), butyne (C4H6), etc.
PPM: represents parts per million, volume concentration (ppm), represents the volume of pollutants contained in one million volumes of air. Overseas imported units. Commonly used in units of toxic and harmful gases, such as hydrogen sulfide (H2S), ammonia (NH3), hydrogen fluoride (HF), hydrogen chloride (HCL), chlorine (CL2), etc.; smaller than PPM is PPb, 1PPM=1000ppb;
Gas molar volume: the volume occupied by gas per unit amount of substance, symbol Vm, commonly used units are L/mol or m3/mol. Under standard conditions (0°C, 101KP state), the volume occupied by 1 mol of any gas is approximately 22.4L.
mg/m3 mass concentration unit---common gas units, Chinese units, for example: HCL 0-100mg/m3; ug/m3 (smaller than mg/m3) 1mg/m3=1000ug/m3;
Units can also be converted into each other 1%VOL=10000PPM
1PPM=M/22.4 mg/m3
These units are used to express the concentration or volume of gas under different conditions. Select the appropriate unit for detection based on specific gas detection needs.
