Reactive gases are defined as gases which, because of their high chemical activity, are easily sorbed (adsorbed) by the exposed surfaces of gas detection systems including detector housings, calibration adapters, and remote sample draw accessories (tubing). Because of their greater tendency to be depleted from a gas sample by the exposed surfaces of gas detection systems, special care must be taken to ensure accurate monitoring results. The principal danger is that failure to use compatible materials and proper calibration procedures can result in dangerously inaccurate (low) readings and increased response times.
Unlike non-reactive gases, reactive gases require higher flow (they will use a 1.0 LPM regulator, instead of a 0.5 LPM) and need corrosion-resistant equipment as corrosive and sticky (stainless steel regulators and Teflon tubing). H2S represents no considerable reactivity.
A list of Reactive and Non-Reactive Gases to help when choosing Calibration or Bump test gas cylinders and accessories.
| Compound | Chemical Formula | Type |
| Hydrogen Sulphide | H2S | Reactive |
| Sulphur Dioxide | SO2 | Reactive |
| Nitric Oxide | NO | Reactive |
| Nitrogen Dioxide | NO2 | Reactive |
| Ammonia | NH3 | Reactive |
| Chlorine | Cl2 | Reactive |
| Hydrogen Chloride | HCl | Reactive |
| Ethylene Oxide | C2H4O (ETO) | Reactive |
| Carbonyl Sulphide | COS | Reactive |
| Methyl Mercaptan | CH3SH | Reactive |
| Ethyl Mercaptan | C2H5SH | Reactive |
| Propyl Mercaptan | C3H7SH | Reactive |
| Butyl Mercaptan | C4H9SH | Reactive |
| Hydrogen Cyanide | HCN | Reactive |
| Silane | SiH4 | Reactive |
| Phosphine | PH3 | Reactive |
| Nitrogen | N2 | Non-Reactive |
| Oxygen | O2 | Non-Reactive |
| Methane | CH4 | Non-Reactive |
| Helium | He | Non-Reactive |
| Carbon Dioxide | CO2 | Non-Reactive |
| Hydrogen | H2 | Non-Reactive |
| Carbon Monoxide | CO | Non-Reactive |
| Nitrous Oxide | N2O | Non-Reactive |
| Sulphur Hexafluoride | SF6 | Non-Reactive |
| Argon | Ar | Non-Reactive |
| Acetylene | C2H2 | Non-Reactive |
| Ethylene | C2H4 | Non-Reactive |
| Ethane | C2H6 | Non-Reactive |
| Propylene | C3H6 | Non-Reactive |
| Propane | C3H8 | Non-Reactive |
| Iso-Butane | i-C4H10 | Non-Reactive |
| Butane | C4H10 | Non-Reactive |
| 1-Butene | 1-C4H8 | Non-Reactive |
| cis-2-Butene | cis-2,C4H8 | Non-Reactive |
| trans-2-Butene | trans-2-C4H8 | Non-Reactive |
| 1-3, Butadiene | 1,3-C4H6 | Non-Reactive |
| 1,2, Butadiene | 1,2-C4H6 | Non-Reactive |
| Pentane | C5H12 | Non-Reactive |
| n-Pentane | n-C5H12 | Non-Reactive |
| Iso-Pentane | i-C5H12 | Non-Reactive |
| neo-Pentane | n-C5H12 | Non-Reactive |
| Hexane | C6H14 | Non-Reactive |
| Vinyl Chloride | C2H3Cl | Non-Reactive |
| Heptane | C7H16 | Non-Reactive |
| Octane | C8H18 | Non-Reactive |
| Nonane | C9H20 | Non-Reactive |
| Decane | C10H22 | Non-Reactive |
| Undecane | C11H24 | Non-Reactive |
| Dodecane | C12H26 | Non-Reactive |
| Tridecane | C13H28 | Non-Reactive |
| Tetradecane | C14H30 | Non-Reactive |
| Pentadecane | C15H32 | Non-Reactive |
| Hexadecane | C16H34 | Non-Reactive |
| Benzene | C6H6 | Non-Reactive |
| Toluene | C6H5-CH3 | Non-Reactive |
| Xylene | C8H10 | Non-Reactive |
| Ethylbenzene | C8H10 | Non-Reactive |
| Ethanol | C2H5OH | Non-Reactive |
| Methanol | CH3OH | Non-Reactive |
| Iso-Butylene | i-C4H8 | Non-Reactive |
| Refrigerants | various | Non-Reactive |