IEC 60079-29-1:2016+A1:2020 specifies general requirements for construction, testing and performance, and describes the test methods that apply to portable, transportable and fixed equipment for the detection and measurement of flammable gas or vapour concentrations with air. The equipment, or parts thereof, is intended for use in explosive atmospheres and in mines susceptible to firedamp. This second edition of IEC 60079-29-1 cancels and replaces the first edition of IEC 60079-29-1:2007 series and constitutes a technical revision. Refer to the Forward of the document for a listing of the extensive changes between this edition and the previous edition. The contents of the interpretation sheets 1 and 2 (2019-04) have been included in this copy. This consolidated version consists of the second edition (2016) and its amendment 1 (2020). Therefore, no need to order amendments in addition to this publication. Keywords: detection and measurement of flammable gas or vapour concentrations with air, explosive atmospheres, mines susceptible to firedamp, explosion hazard