Relation between MIE and gasgroup of equipment
Equipment that is certified for used in hazardous areas must be Ex certified according to the applicable standards. Substances which create a hazardous area can be ignited. The energy needed for ignition is expressed with the Minimum Ignition Energy. Equipment which can be used within hazardous area may not be able to ignite the substances which create the hazardous area. This means that the possible energy from that equipment must be less than the MIE of the substances.
The following gasgroups are devided:
Gasgroup IIA -> Equipment is able to create a spark with a maximum energy of 200µJ
Gasgroup IIB -> Equipment is able to create a spark with a maximum energy of 60µJ
Gasgroup IIC -> Equipment is able to create a spark with a maximum energy of 20 µJ
The applicable gasgroup can be found in substance data, like IEC 60079-20-1. This data is also incorporated in the substance database in Hazcalc.