FOREWORD
INTRODUCTION
1 General
1.1 Scope
1.2 Normative references
2 Definitions and terms
3 Safety and area classification
3.1 Safety principles
3.2 Area classification objectives
4 Area classification procedure
4.1 General
4.2 Sources of release
4.3 Type of zone
4.4 Extent of zone
4.4.1 Release rate of gas or vapour
4.4.2 Lower explosive limit (LEL)
4.4.3 Ventilation
4.4.4 Relative density of the gas or vapour
when it is released
4.4.5 Other parameters to be considered
4.4.6 Illustrative examples
5 Ventilation
5.1 General
5.2 Main types of ventilation
5.3 Degree of ventilation
5.4 Availability of ventilation
6 Documentation
6.1 General
6.2 Drawings, data sheets and tables
Annex A (informative) Examples of sources of release
Annex B (informative) Ventilation
Annex C (informative) Examples of hazardous area
classification
Figure C.1 - Preferred symbols for hazardous area
zones
Figure C.2 - Schematic approach to the classification
of hazardous areas