Information about ATEX

What is ATEX (Ex)?
ATEX is an acronym that stands for ‘ATmosphere EXplosible’. At the same time, ATEX is an abbreviation for European Directive 94/9/EC concerning the placement on the market of explosion-protected electrical and mechanical equipment.

What equipment should be used in which environments?
Directive 94/9/EC defines groups of devices and device categories. There are two groups of devices:
Group I: All devices for underground mine operations.
Group II: All other areas.
The groups are classified according to frequency of occurrence of an explosive atmosphere and subclassified into
device categories.

ATEX product directive 94/9/EC
The main purpose of the Directive is to protect people who work in hazardous areas or who might be affected by explosions. The directive comprises health and safety requirements that the manufacturer must consider and must
demonstrate through appropriate conformity assessment procedures. Since 30 June 2003, only such devices, components and protective systems may be placed on the market for use in potentially explosive atmospheres that meet ATEX Product Directive 94/9/EC.

Temperature classes in the ATEX area
To facilitate the configuration of a plant, 6 temperature classes (T1 to T6) have been established for permissible surface temperatures. Based on their corresponding ignition temperatures, certain flammable gases and vapours can be classified in these temperature classes.

Classification of hazardous ATEX zones (gas/dust)

Gases: Zones    Zonen 0-2
Dusts: Zones    Zonen 20-22
Zone 0/20    Areas in which an explosive atmosphere
exists over a prolonged period.
Zone 1/21:    Areas in which an explosive atmosphere
exists occasionally.
Zone 2/22:    Areas in which an explosive atmosphere
is only likely to occur for brief periods.

Testing of devices
Manufacturers or operators must check their devices under Directive 94/9/EC in terms of the requirement of CE marking.

The following are checked:

  1. Electrical devices
  2. Non-electrical devices
  3. Non-electrical components

Type of ignition protection and temperatures
Type of ignition protection: - Pressurized encapsulation (d) - Increased safety (e) - Oil encapsulation (o) - Overpressure encapsulation (p) - Powder filling (q) - Cast encapsulation (m) - Non-sparking (n) - Intrinsically Safe (i)

Temperature class: Ignition temperature:
T1 450°C
T2
300°C
T3
200°C
T4
135°C
T5
100°C
T6
85°C

Marking
Each device must be provided with a nameplate and the following details:

Ex EC type examination certificate
II II C Device group
1 Category requirements
G Explosive atmosphere
EEx Built according to European standards
ia Type of ignition protection
T6 Temperature class

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