Gas Grouping
| Typical gas hazard | IEC 60079-0 Cenelec EN50014 | North AmericaNEC Article 500 (Class I)* | Minimum ignition energy (microjoules) |
| Acetylene | IIC | A | 20 |
| Hydrogen | IIC | B | 20 |
| Ethylene | IIB | C | 60 |
| Propane | IIA | D | 180 |
* North America hazardous categories: Class I (Gases & vapours); Class II (Dusts); Class III (Fibres)
