Explosion Protection

The important principles for integrated safety explosion protection are as follows:

  • Measures are taken to avoid hazardous atmospheres whenever possible.
  • Measures are taken which prevent the ignition of hazardous atmospheres.
  • Measures are taken which limit the explosive effect to a safe degree.

 

This differs from:

Primary explosive protection

These are precautions taken to prevent or restrict the formation of hazardous explosive atmospheres.

Secondary explosive protection

This covers the second group of measures, which are intended to prevent the ignition of an atmosphere that is capable of exploding.

 

 

Definition is in line with Directive 1999/92/EC (ATEX 137) Reference Zone according to CENELEC IEC Required equipment category Required identification according to 94/9/EC ATEX95 
Area in which a potentially explosive atmosphere as a mixture of air and flammable gases, vapors or mist is present, either frequently or over a longer period. > 1000 h / a 0 1G G
Area in which under normal operating conditions a potentially explosive atmosphere as a mixture of air and flammable gases, vapors or mists may occasionally form. 100 - 1000 h / a 1 2G  (1G also possible) G
Area in which under normal operating conditions a potentially explosive atmosphere as a mixture of air and flammable gases, vapors or mists may occur for only a short period. <10 h / a 2 3G  (1G 2G also possible) G
Area in which a potentially explosive atmosphere in the form of a cloud of flammable air-borne dust is present, either continuously for long periods or frequently. > 1000 h / a 20 1D D
Area in which under normal operation a potentially explosive atmosphere in the form of a cloud of dust in the air can occasionally form. 100 - 1000 h / a 21 2D  (1D also possible) D
Area in which under normal operation a potentially explosive atmosphere in the form of a cloud of combustible dust in air is not normally present, although may occur for only a short period <10 h / a 22 3D  (1D 2D also possible) D

 

 

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