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 and EPL Gc for use in explosive atmospheres of flammable gas and vapour, and

– Group III EPL Db and EPL Dc 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 document includes those tests of the engine and its ancillary devices that are required to verify compliance with this document.

This document applies to both reciprocating internal combustion engines with compression ignition for EPL Mb, Gb, Gc, Db, Dc and gaseous fuelled spark ignition engines for EPL Gc. See Annex G.

This document does not define requirements relating to the driven machinery and equipm ent.

This document does not apply to

– explosive mixtures of vapours and gases, which tend to self -decompose (for example carbon disulphide (CS2), ethylene oxide (C2H4O), acetylene (C2H2)) or which are chemically unstable;

• hydrogen fueled engines, including blends;

• 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

• electrical ignition spark systems. Note 1 Spark ignition systems used with equipment covered by ISO/IEC 80079 -41 is covered by IEC 60079- 45

This document 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 document does not specify requirements for safety, other than those directly related to the possibility of ignition of flammable mixtures in the surrounding atmosphere which can lead to an explosion.

The standard atmospheric conditions (relating to the explosion characteristi cs of the atmosphere) under which it can 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 instruct ions 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 ignitability

NOTE 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 document supplements and modifies the general requirements of IEC 60079 -0:2017. Where a requirement of this document conflicts with a requirement of IEC 60079 -0:2017 as far as applicable for Ex engines, the requirement of this standard takes precedence.

NOTE 5 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.

Purpose

ISO/IEC 80079-41 provides the technical, design, construction, testing, marking requirements for Ex; EPL Mb, EPL Gb, EPL Db, EPL Gc & EPL Dc, spark-ignited and compression-ignited reciprocating internal combustion engines.

IEC 60079-45 provides the electrical requirements for Ex; EPL Gc, spark -ignited, reciprocating, internal combustion, engines. These requirements are a “special case” requiring specialised experts. The mechanical and associated requirements for EPL Gc engines are in IS O/IEC 80079-41.

PT 60079-45 and PT 80079-41 have several members in common to ensure no conflicts and that demarcation is maintained.