This part of IEC 60079-29 gives guidance on, and recommended practice for, the selection, installation, safe use and maintenance of electrically operated group II apparatus intended for use in industrial and commercial safety applications for the detection and measurement of flammable gases complying with the requirements of IEC 60079-29-1.This first edition of IEC 60079-29-2 cancels and replaces the first edition of IEC 61779-6:1999 and constitutes a technical revision with many changes with respect to the previous edition.