Standards Development

Scope

This part of ISO/IEC 80079 specifies the technical requirements for design, construction, testing, marking and the information required for use to avoid or minimise the possibility of ignition which could from reciprocating internal combustion engine intended for use in explosive atmospheres including:Group I EPL Mb for use in underground workings susceptible to firedamp or combustible dust, Group II EPL Gb for use in explosive atmospheres of flammable gas and vapour, and Group III EPL Db for use in explosive atmospheres of combustible dust. For EPL Gc and Dc engines, only normal operating conditions need to be taken into account. Malfunctions need not be considered (see B.2.1).This part of ISO/IEC 80079 includes those tests of the engine and its ancillary devices that are required to verify compliance with this standard.This part of ISO/IEC 80079 applies to both reciprocating internal combustion engines with compression ignition for EPL Mb, Gb, Gc, Db, Dc and spark ignition engines for EPL Gc. See Annex G.This part of ISO/IEC 80079 does not define requirements relating to the driven machinery and equipment.This part of ISO/IEC 80079 does not apply toexplosive mixtures of vapours and gases, which tend to self-decompose (for example carbon disulphide (CS2), ethylene oxide (C2H4O), acetylene) or which are chemically unstable;engines used in areas for the processing, manufacture or storage of explosives; gasoline and other spark ignited engines where the fuel is injected into the combustion chamber as a liquid; or high voltage electrical ignition systems. This part of ISO/IEC 80079 solely deals with explosion protection requirements. Requirements on gaseous or particulate exhaust emissions are not covered by this standard.General safety requirements are not included in this International Standard.NOTE 1 General safety requirements (for example those common to internal combustion engines) are covered for the EU in EN 1679-1:1998+A1:2011.This standard does not specify requirements for safety, other than those directly related to the possibility of ignition which can lead to an explosion.The standard atmospheric conditions (relating to the explosion characteristics of the atmosphere) under which it may be assumed that the engine may be operated 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.An engine for use outside of the standard atmospheric conditions is to be designed, constructed tested and marked for those conditions. The ignition hazard assessment, ignition, protection provided, additional testing (if necessary) manufacturer’s technical documentation and instructions to the user are intended toclearly demonstrate the engine’s suitability for the conditions.NOTE 2 It is recognised that changes in temperature and pressure have an influence on the characteristics of the explosive atmosphere including ignitabilityNOTE 3 IEC TS 60079-43 gives information for equipment used in explosive atmospheres in environmental conditions which include ambient temperatures below –20 °C and additional adverse conditions, including maritime applications.NOTE 4 Reciprocating internal combustion engines are not considered as pressure vessels.This standard supplements and modifies the general requirements of IEC 60079-0:2017, as shown in Table 1. Where a requirement of this standard conflicts with a requirement of IEC 60079-0:2017 as far as applicable for Ex engines, the requirement of this standard takes precedence.On-going inspection, maintenance and repair aspects play an important role in control of hazardous area installations and the user’s attention is drawn to IEC 60079-17, IEC 60079-19 and manufacturer’s instructions for further information concerning these aspects.