Gives guidance on the selection, installation, use and maintenance of electrically operated group II apparatus for the detection and measurement of flammable gases complying with the requirements of AS/NZS 61779.1, AS/NZS 61779.4 and AS/NZS 61779.5. For the purpose of this Standard, flammable gases shall include flammable vapours. This Standard applies only to group II apparatus intended for use in industrial and commercial safety applications, involving areas classified in accordance with AS 2430.1 (in Australia) or NZS 6101.1 (in New Zealand) and AS/NZS 2430 Parts 3.1 to 3.9.