Gives general requirements for the construction and testing and describes the test methods applicable to portable, transportable and fixed apparatus for detecting and measuring flammable gas or vapour concentrations with air. The apparatus, or parts of apparatus are meant for use in potentially explosive atmospheres and in mines susceptible to firedamp. This standard is supplemented by the following standards: IEC 61779-2, IEC 61779-3, IEC 61779-4 and IEC 61779-5.