Operating / Mounting instruction
 
8  192-550003N10 ETH ATEX December 2019 
1.5  Introduction to ATEX 
In this chapter you can read about: 
Explosive atmospheres ...................................................................................................... 8 
Harmonized European ATEX Standard.............................................................................. 8 
Zone classification / device categories ............................................................................... 8 
Type of explosion protection .............................................................................................. 9 
Explosion subgroup ......................................................................................................... 10 
Temperature classes ....................................................................................................... 10 
ATEX and machinery directive ......................................................................................... 10 
ATEX = “ATmosphère EXplosible”   
Introduction to the European ATEX directive   
 
 
1.5.1.  Explosive atmospheres 
Directive 2014/34/EC defines an explosive atmosphere as a mixture of:   
a) flammable substances - gases, vapors, mists or dusts   
b) and air   
c) under defined atmospheric conditions   
d) in which, after ignition has occurred, combustion spreads to the entire unburned 
mixture   
(NOTE: dust may not burn entirely after ignition).   
A “potentially explosive atmosphere” is an atmosphere which could become 
explosive due to local and operational conditions. Devices concerned by directive 
2014/34/EC are defined as designed for the use in potentially explosive 
atmospheres. 
 
1.5.2.  Harmonized European ATEX Standard 
The EC accepted two harmonized directives for health and safety. 
Requirements for machinery and equipment 
Directive 2014/34/EC (ATEX 95a) defines the minimum safety requirements in EU 
member states for products used in potentially explosive atmospheres.   
Requirements for OEM / user 
ATEX directive 99/92/EC (ATEX 137) sets out the minimum requirements for 
improving the health and safety protection of workers potentially at risk from 
explosive atmospheres with regard to workplace, working conditions and the 
handling of products and materials. This directive classifies the workplace into 
zones and defines criteria for categorizing the products within the zones.