Division of hazardous areas for explosive gas atmospheres

1.1 Division of hazardous areas of explosive gas atmospheres

Different countries and regions divide explosion hazardous areas according to their own standards. According to the frequency and duration of the explosive gas mixture, my country divides the explosive gas environment into zone O, zone 1 and zone 2. (consistent with IEC International Electrotechnical Commission)

Zone 0: Continuous or long-term presence of explosive gas mixtures.

Zone 1: Environments where explosive gas mixtures may occur during normal operation.

Zone 2: An environment in which an explosive gas mixture is unlikely to occur during normal operation or where an explosive gas mixture exists only for a short time if it occurs.

Zone 0 generally only exists in the internal gas space of sealed containers, storage tanks, etc. In the actual design process, Zone 1 rarely exists, and most cases belong to Zone 2.

Explosion-proof electrical equipment is divided into two categories

1.2 Explosion-proof electrical equipment is divided into two categories:

Class I coal mine underground electrical equipment

Class II electrical equipment used in places other than mines

1.3 Class II electrical equipment is divided into three categories IIA, IIB, IIC according to the maximum test safety clearance or minimum ignition current ratio suitable for explosive gas mixtures; and is divided into six groups T1-T6 according to their maximum surface temperature.

1.4 Explosive gas mixtures are grouped by ignition temperature, see Table 1.

1.5 Explosive gas mixtures are classified according to their maximum test safety gap (MESG) or minimum ignition current ratio (MICR)

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