Zone classification
European and IEC Classification Definition of zone or division North American Classification
Zone 0 (gases / Vapors) An area in which an explosive mixture is continuously present or present for long periods Class I Division 1 (gases)
Zone 1 (gases / Vapors) An area in which an explosive mixture is likely to occur in normal operation Class I Division 1 (gases)
Zone 2 (gases / Vapors) An area in which an explosive mixture is not likely to occur in normal operation and if it occurs it will exist only for a short time. Class I Division 2 (gases)
Zone 20 (dusts) An area in which an explosive mixture is continuously present or present for long periods Class II Division 1 (dusts)
Zone 21 (dusts) An area in which an explosive mixture is likely to occur in normal operation Class II Division 1 (dusts)
Zone 22 (dusts) An area in which an explosive mixture is not likely to occur in normal operation and if it occurs it will exist only for a short time. Class II Division 2 (dusts)