scope:

This Standard provides examples of area classification for areas associated with the production, processing, handling and storage of heavier-than-air and lighter-than-air flammable gases. It is Part of the AS/NZS 2430.3 series which recommends the classifications of several commonly occurring situations and should be read in conjunction with AS/NZS 2430.3.1.

Caution should be exercised when considering gases with densities close to that of air, or any lighter-than-air gas which may be cooled substantially below ambient air temperature (e.g. by expansion from a compressed liquefied, or refrigerated liquefied state); such gases may behave as either heavier-than-air gases or lighter-than-air gases and therefore the applicable Clauses should be considered.

For flammable gases in refineries and major processing plants reference should be made to AS/NZS 2430.3.5, which uses the Generalized Method of classification.

All pressures quoted in this Standard are gauge pressures unless specified otherwise.