Hazard class 2
Gases can be a pure gas or a mixture of one or more gases. They are defined by dangerous goods regulations as substances which have a vapour pressure greater than 300 kPa (3 bar) at 50°C, or which at a standard pressure of 101 kPa are completely gaseous at 20°C.
Substances and articles of Class 2 have been assigned to one of the following divisions:
Division 2.1
Flammable gas
Division 2.2
Non-flammable compressed gas
Division 2.3
Toxic gas
Subdivision of gases
Gases are sub-divided into compressed gases, liquefied gases, refrigerated liquefied gases, dissolved gases, aerosol dispensers and receptacles, other articles containing gas under pressure, non-pressurized gases subject to special requirements (gas samples), chemicals under pressure and adsorbed gas.Except for aerosols and chemicals under pressure, Class 2 gases are divided between the following groups according to their hazardous properties:
| A | Asphyxiant |
| O | Oxidizing |
| F | Flammable |
| T | Toxic |
| TF | Toxic, flammable |
| TC | Toxic, corrosive |
| TO | Toxic, oxidizing |
| TFC | Toxic, flammable, corrosive |
| TOC | Toxic, oxidizing, corrosive |
Reasons for regulation
Gases can pose serious hazards due to their flammability, potential as asphyxiants, ability to oxidize and/or their toxicity or corrosiveness.
Examples of commonly transported explosives
Examples for Class 2 dangerous goods are aerosols, compressed gas, fire extinguishers, refrigerant gases, lighters, acetylene, carbon dioxide, helium, hydrogen, oxygen, nitrogen, natural gas, petroleum gases, liquified, butane, propane, methane, ethylene.
