The measurement range refers to the range within which a gas detector can operate normally. For example, the measurement range for combustible gases is typically 0–100% LEL, while the standard measurement range for H2S is 0–100 ppm.
Common gas measurement range and high/low alarm values
| tracer gas | range | Alarm value | least count | response time |
| combustible gas (EX) | 0-100%LEL | 20%LEL | 1%LEL | ≤ 10 seconds |
| oxygen (O2) | 0-30%VOL | 19.5%Vol | 0.1%Vol | ≤ 15 seconds |
| carbon monoxide(CO) | 0-1000ppm | 50ppm | 1ppm | ≤25 seconds |
| carbon dioxide (CO2) | 0-5%VOL | 0.2%VOL | 0.01%VOL | ≤30 seconds |
| formaldehyde (CH2O) | 0-50ppm | 10ppm | 0.1ppm | ≤ 40 seconds |
| ozone (O3) | 0-20ppm | 5ppm | 0.1ppm | ≤30 seconds |
| Hydrogen sulfide(H2S) | 0-100ppm | 15ppm | 1ppm | ≤ 30 seconds |
| sulfur dioxide (SO2) | 0-20ppm | 5ppm | 0.1ppm | ≤ 30 seconds |
| nitric oxide (NO) | 0-250ppm | 20ppm | 1ppm | ≤60 seconds |
| nitrogen dioxide(NO2) | 0-20ppm | 5ppm | 0.1ppm | ≤ 60 seconds |
| nitrogen oxide (NOX) | 0-100ppm | 20ppm | 1ppm | ≤ 60 seconds |
| chlorine gas(CL2) | 0-20ppm | 5ppm | 0.1ppm | ≤ 60 seconds |
| ammonia gas(NH3) | 0-100ppm | 15ppm | 0.1ppm | ≤60 seconds |
| hydrogen (H2) | 0-1000ppm | 50ppm | 1ppm | ≤ 60 seconds |
| hydrogen cyanide(HCN) | 0-20ppm | 2ppm | 0.1ppm | ≤ 60 seconds |
| Hydrogenchloride(HCL) | 0-50ppm | 5ppm | 0.1ppm | ≤60 seconds |
| Phosphine(PH3) | 0-20ppm | 2ppm | 0.1ppm | ≤ 60 seconds |
| Ethylene oxide (ETO) | 0-100ppm | 20ppm | 1ppm | ≤120 Seconds |
| phosgene (COCL2) | 0-100ppm | 5ppm | 1ppm | ≤ 60 seconds |
| silane (SiH4) | 0-50ppm | 10ppm | 0.1ppm | ≤ 60 seconds |
| Fluoride (F2) | 0-20ppm | 5ppm | 0.1ppm | ≤ 30 seconds |
| hydrogen fluoride(HF) | 0-20ppm | 5ppm | 0.1ppm | ≤30 seconds |
| bromine hydride(HBr) | 0-50ppm | 10ppm | 0.1ppm | ≤60 seconds |
| arsenic hydride(AsH3) | 0-20ppm | 1ppm | 0.1ppm | ≤ 30 seconds |
| Hydrazine, hydrazine(N2H4) | 0-100ppm | 20ppm | 1ppm | ≤ 60 seconds |
| Tetrahydrothiophene(THT) | 0-100mg/m3 | 20mg/m3 | 1mg/m3 | ≤ 60 seconds |
| Bromine (BR2) | 0-20ppm | 5ppm | 0.1ppm | ≤ 60 seconds |
| ethyne (C2H2) | 0-100%LEL | 20%LEL | 1%LEL | ≤60 seconds |
| ethylene (C2H4) | 0-100%LEL | 20%LEL | 1%LEL | ≤ 60 seconds |
| alcohol (C2H6O) | 0-100%LEL | 20%LEL | 1%LEL | ≤30 seconds |
| carbinol (CH4O) | 0-100%LEL | 20%LEL | 1%LEL | ≤30 seconds |
| carbon disulfide (SC2) | 0-50ppm | 10ppm | 0.1ppm | ≤120 Seconds |
| acrylonitrile (C3H3N) | 0-50ppm | 10ppm | 0.1ppm | ≤60 seconds |
| aminomethane(CH5N) | 0-50ppm | 10ppm | 0.1ppm | ≤60 seconds |
| styrene (C8H8) | 0-100ppm | 20ppm | 1ppm | ≤30 seconds |
| chlorylene (C2HCL3) | 0-50ppm | 20ppm | 0.1ppm | ≤ 60 seconds |
| Celfume (CH3Br) | 0-100ppm | 20ppm | 1ppm | ≤30 seconds |
| benzene (C6H6) | 0-100ppm | 20ppm | 1ppm | ≤ 30 seconds |
| methylbenzene(C7H8) | 0-100ppm | 20ppm | 1ppm | ≤ 30 seconds |
| dimethylbenzene(C8H10) | 0-100ppm | 20ppm | 1ppm | ≤30 seconds |
| Sulfur hexafluoride(SF6) | 0-100ppm | 20ppm | 1ppm | ≤30 seconds |
| VOC/TVOC | 0-1000ppm | 50ppm | 1ppm | ≤ 30 seconds |
| Laughing gas (N2O) | 0-100ppm | 20ppm | 0.01ppm | ≤ 30 seconds |
| argon (Ar) | 0-100%vol | 20%Vol | 1vol | ≤ 30 seconds |
