IEC 60079-0 ED. 6.0 2011 - Explosive atmospheres - Part 0: Equipment - General requirements

This part of IEC 60079 specifies the general requirements for construction, testing and marking of electrical equipment and Ex Components intended for use in explosive 
atmospheres. The standard atmospheric conditions (relating to the explosion characteristics of the atmosphere) under which it may be assumed that electrical equipment can 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. 

This standard and other standards supplementing this standard specify additional test requirements for equipment operating outside the standard temperature range, but further 
additional consideration and additional testing may be required for equipment operating outside the standard atmospheric pressure range and standard oxygen content, particularly 
with respect to types of protection that depend on quenching of a flame such as ‘flameproof enclosure “d”’ (IEC 60079-1) or limitation of energy, ‘intrinsic safety “i”’ (IEC 60079-11). 

You can see the content of the present standard on the web site of IEC at the following address : http://www.iec-normen.de/

CONTENTS 
FOREWORD
1 Scope
2 Normative references
3 Terms and definitions
4 Equipment grouping
4.1 Group I
4.2 Group II
4.3 Group III
4.4 Equipment for a particular explosive atmosphere
5 Temperatures
5.1 Environmental influences
5.1.1 Ambient temperature
5.1.2 External source of heating or cooling
5.2 Service temperature
5.3 Maximum surface temperature
5.3.1 Determination of maximum surface temperature
5.3.2 Limitation of maximum surface temperature
5.3.3 Small component temperature for Group I or Group II electrical equipment
6 Requirements for all electrical equipment
6.1 General
6.2 Mechanical strength of equipment
6.3 Opening times
6.4 Circulating currents in enclosures (e.g. of large electrical machines)
6.5 Gasket retention
6.6 Electromagnetic and ultrasonic energy radiating equipment
6.6.1 Radio frequency sources
6.6.2 Lasers or other continuous wave sources
6.6.3 Ultrasonic sources
7 Non-metallic enclosures and non-metallic parts of enclosures
7.1 General
7.1.1 Applicability
7.1.2 Specification of materials
7.2 Thermal endurance
7.2.1 Tests for thermal endurance
7.2.2 Material selection
7.2.3 Alternative qualification of elastomeric sealing O-rings
7.3 Resistance to light
7.4 Electrostatic charges on external non-metallic materials
7.4.1 Applicability
7.4.2 Avoidance of a build-up of electrostatic charge on Group I or Group II electrical equipment 
7.4.3 Avoidance of a build-up of electrostatic charge on equipment for Group III
7.5 Accessible metal parts
8 Metallic enclosures and metallic parts of enclosures