ATEX Ratings, Intrinsic Safety, Hazardous Areas and Explosive Atmospheres
Please note that this page provides helpful information only, detailed reference should be taken from an appropriate accredited agency or organisation.
Characteristics of Substances
This is the lowest temperature at which a liquid generates sufficient vapour to support ignition. This vapour can be ignited in many ways including temperature or energy (i.e. a spark)
This is the lowest temperature at which the vapour will be ignited. This defines the temperature class.
|Classification of maximum surface temperatures of electrical apparatus (CENELEC)|
|Temp. Class||Max. Surface Temp.|
Apparatus Group (Energy Ignition)
All surface industry gases/vapours are classed as Group II gases. Group II is divided into 3 sub groups:
IIA – High energy is required to ignite. Less intense explosion. (Propane)
IIB – Less energy is required to ignite. More intense explosion. (Ethylene)
IIC – Little energy is required to ignite. Most intense explosion. (Hydrogen)
|Characteristics Of Some Common Flammable Materials|
|Gas/Vapour||Flashpoint||Gas Group||Ignition Temp.||Temp. Class|
|Ethyl Methyl Ether||37ºC||IIB||190ºC||T4|
Note: There is no connection between ignition energy and ignition temperature