ZONE DEFINITIONS

Under IEC rules, the definitions of the Zoning of Hazardous Areas and the forms of protection which are permitted to be used within them in accordance with EN 60079-10 are typically recognised in the case of gas and vapour hazards, as follows :-

Zone 0 An area where an explosive gas atmosphere is present continuously or is present for long periods of time (e.g. 1000 hours or more per year). Permitted form of protection : Ex "ia"

Zone 1 An area where an explosive gas atmosphere may exist under normal operating conditions (e.g. 10 - 1000 hours per year). Permitted forms of protection: Any type of protection suitable for Zone 0 and Ex "d", Ex "ib", Ex "p", Ex "e", Ex "s" and Ex "m"

Zone 2 An area where an explosive gas atmosphere is not likely to exist under normal operating conditions, but if it does it will exist only for a short period of time (e.g. less than 10 hours per year). Often referred to as the "Remotely Hazardous Area". Permitted forms of protection - any type of protection suitable for Zone 0 and 1 and Ex "N" or Ex "n", Ex "o", Ex "q".