ATEX motors for hazardous areas

Fabrika’s line of explosion protected ATEX motors intended for use in potentially explosive atmospheres comprises motors for all zones; 1, 2, 21 and 22.

First step is the classification of hazardous places in one of the zones. The end user shall classify the hazardous areas under his own responsibility. Directive 1999/92/EC provides information regarding ‘Classification of places where explosive atmosphere may occur’. The corresponding standards of reference are EN 60079-10-1 for gas and EN 60079-10-2 for dust.

Here below we give you a step by step guide to the choice of the motors, see table 1:

ATEX motors for hazardous areas

Table 1: ATEX zones defined and explained

In the following, the different categories will be explained.

  1. CE marking: Marks that the device meets CE requirements
  2. Number of the certifying “notified” body: Defines the certification body with unique number
  3. Explosion protection marking: Indicates that the electrical equipment is explosion protected
  4. Device group:
    1. I: Includes electrical equipment intended  for use in underground areas such as mines (Fabrika cannot offer motors for this group)
    2. II: Includes equipment intended for use in other places likely to become endangered by explosive atmospheres (surface plants different from mines)
  5. Category: Group II is sub-divided into two categories:
    1. Category 2/zone 1 and 21: High level of protection
    2. Category 3/zone 2 and 22: Normal level of protection
  6. Ex atmosphere: Defines whether the equipment is placed in an atmosphere with dust (D) or gas (G)
  7. Explosion protected equipment: Is marked with “Ex” no matter the zone
  8. Type of protection: Fabrika electric ATEX motors can have the following types of protection:
    1. Ex db: Encapsulated motor and terminal box for zone 1 gas
    2. Ex db eb: Motor Ex db (encapsulated) and terminal board Ex eb (increased safety) for zone 1 gas
    3. Ex eb: Increased safety for zone 1 gas (NB: Frequency converter duty not allowed for this ATEX type motor)
    4. Ex ec: Non-sparking for zone 2 gas (earlier Ex Na)
    5. Ex tb: Protection by enclosure t for zone 21 dust
    6. Ex tc: Protection for zone 22 dust
  9. Explosion group and explosion subgroup:
    1. II: Gas (NB: IIC is the hardest group and covers IIB and IIA. IIB covers IIA):
      1. IIC Hydrogen, Acetylene, carbon disulfide
      2. IIB Diethyl ether, Ethylene etc.
      3. IIA Propane, Butane, pentane, natural gas etc.
    2. III: Dust
  10. Temperature class with max. surface temperature: In function of their maximum surface temperature the motors are classified in a temperature class (NB: The higher the T value, the higher the protection of the motor temperature class. E.g. covers temperature class T4 temperature class T3 and so on)
  11. Equipment protection level: Marks the protection level of the electrical equipment

 

ATEX motors for hazardous areas

Table 2: ATEX zones visualized

ATEX – background

»ATEX« is the abbreviation of the French name for explosive atmosphere – »atmosphères explosibles«. In the European Union, explosion protection is regulated by directives and laws.

In 1994, the EU issued the EC Directive 94/9/EC »to harmonize the laws of Member States concerning equipment and protective systems intended for use in potentially explosive atmospheres« for this purpose. Article 95 of this directive (before 1997: 100a) addresses manufacturers and importers of explosion protected equipment and regulates the marketing of such equipment by defining the type of construction, certification, manufacturing and quality assurance, marking, operating instructions and declaration of conformity. In technical circles, this directive is inofficially known as ATEX 95 or 100 a.

Beyond this, there is also the Directive 99/92/EC (“ATEX 137”, before 1997 this was still called “ATEX 118a”). This addresses companies operating equipment (work stations and places of work) and makes them responsible for evaluating the danger of explosion at the place of use, i.e. companies must precisely define which type or “category” of explosion protection it actually requires.