This Standard is applicable to flammable gas detection equipment which is intended to provide continuous sensing and an indication, alarm or other output function; the purpose of which is to indicate a potential explosion hazard and in some cases, to initiate automatic or manual protective action(s).

This Standard is applicable to equipment intended to be used for commercial, industrial and non-residential safety applications, as well as diffusion equipment and aspirated equipment with integrated sampling systems.

This Standard does not apply to

— external sampling systems;

— equipment intended for use in mines susceptible to firedamp;

— equipment of laboratory or scientific type;

— equipment used only for process monitoring and/or control purposes;

— open path (line of sight) detectors (only equipment with very short optical paths intended for use where the concentration is uniform over the optical path are within the scope of this Standard).

For equipment used for sensing the presence of multiple gases, this Standard applies only to the detection of flammable gas or vapour.

NOTE 1 This Standard is intended to provide for the supply of equipment giving a level of safety and performance suitable for general purpose applications.

NOTE 2 All equipment calibrated on specific gases or vapours can not be expected to correctly indicate on other gases or vapours.

NOTE 3 Indication of measured concentration in % (v/v) or vol ppm can also be available for equipment with a measurement range of over 20 % LEL up to and including 100 % LEL or a measurement range of up to 20 % LEL. One ppm is equal to 10^-6 in volume fraction. In that case, units of measurement might need to be selected upon agreement between the manufacturer and test laboratory when verifying the performance requirements of Annex A.

NOTE 4 The International Standard corresponding to this Standard and the symbol of degree of correspondence are as follows.

IEC 60079-29-1:2016 Explosive atmospheres—Part 29-1: Gas detectors— Performance requirements of detectors for flammable gases (MOD)

In addition, symbols which denote the degree of correspondence in the contents between the relevant International Standard and JIS are IDT (identical), MOD (modified), and NEQ (not equivalent) according to ISO/IEC Guide 21-1.

• temperature -20 °C to 60 °C;
• pressure 80 kPa (0,8 bar) to 110 kPa (1,1 bar);
• and air with normal oxygen content, typically 21 % v/v.

This part of ISO/IEC 80079 applies for equipment and components according to EPL Mb to be used in explosive atmospheres containing firedamp and/or combustible dust. For equipment and components according to EPL Ma, the requirements of this standard and of ISO 80079-36 and IEC 60079-0 apply. It is necessary to take account of external conditions to the equipment which may affect the hazard and the resultant protection measures. These measures may include ventilation, gas detection or gas drainage.

This part of ISO/IEC 80079 also deals with the prevention of ignitions of explosive atmospheres caused by burning (or smouldering) of combustible material such as fabric fibres, plastic "O"-rings, rubber seals, lubricating oils or greases used in the construction of the equipment if such items could be an ignition source. For example, the mechanical failure of rotating shaft bearings can result in frictional heating that ignites its plastic cage, plastic seal or lubricating grease. Detailed requirements and test procedures for the fire protection of conveyer belts are not part of this part of ISO/IEC 80079.

The standard atmospheric conditions for determination of characteristics of combustible dusts are:

• temperature -20 °C to 60 °C,
• pressure 80 kPa (0,8 bar) to 110 kPa (1,1 bar) and
• air with normal oxygen content, typically 21 % v/v.

The test methods defined do not apply to:

• recognized explosives, propellants (e.g. gunpowder, dynamite), or substances or mixtures of substances which may, under some circumstances, behave in a similar manner or
• dusts of explosives and propellants that do not require atmospheric oxygen for combustion, or to pyrophoric substances.

This first edition cancels and replaces the first edition of IEC 61241-2-1 published in 1994, the first edition of IEC 61241-2-2 published in 1993 and the first edition of IEC 61241-2-3 published in 1994, combining the requirements into a single document, and is considered to constitute a technical revision. Significant changes with respect to IEC 61241-2-1:1994, IEC 61241-2-2:1993 and IEC 61241-2-3:1994 can be found in the foreword of the document.