Hazardous area is an area where fire and explosion may occurred due to presence of an explosive gas or combustible dust atmospheres.
Note1: The acronym for ATmospheres EXplosible is ATEX.
Note2: Danger level are classified in Europe with Zones and in North America with Classes/Divisions.
Hazardous area according to European standards (Zones):
- A) Explosive gas atmospheres (Ignitable concentrations of flammable gases or vapours)
- Zone 0 (Class I Division 1): Area in which an explosive gas atmosphere is present continuously or for long periods of time (will frequently occur).
- Zone 1 (Class I Division 1): Area in which an explosive gas atmosphere is likely to occur (occasionally in normal operation)
- Zone 2 (Class I Division 2): Area in which an explosive gas atmosphere is not likely to occur in normal operation and only occur infrequently for a short period.
- B) Combustible dust atmospheres (combustible dusts or ignitable fibers and flyings)
- Zone 20 (Class II Division 1): Area in which a combustible dust atmosphere is present continuously or for long periods of time (will frequently occur).
- Zone 21 (Class II Division 1): Area in which an combustible dust atmosphere is likely to occur (occasionally in normal operation)
- Zone 22 (Class II Division 2): Area in which a combustible dust atmosphere is not likely to occur in normal operation and only occur infrequently for a short period.
Note3: The material type for hazardous atmosphere and location are defined by the Groups.
Note4: In European standards we have 3 groups (I,II and III) but in North America there are 7 groups (A,B,C,D,E,F,G) for classification.
1- Group I: Mines
2- Group II: Explosive gas (except mines)
- A: Propane, acetone, benzene, butane, methane, petrol, hexane, paint solvents or gases and vapours of equivalent hazard.
- B: Ethylene, propylene oxide, ethylene oxide, butadiene, cyclopropane, ethyl ether, or gases and vapours of equivalent hazard.
- C: Acetylene, hydrogen, carbon disulphide or gases and vapours of equivalent hazard
3- Group III: Explosive dust
- A: Combustible flyings
- B: Non-conductive dust
- C: Conductive dust
Related standards:
Leave a Reply