（1） Flammable and explosiveClassification of Gas Environment Zones
Zone 0:In normal circumstances, places where flammable and explosive gas mixtures occur continuously, frequently, or exist for a long time, such as certain parts of oil drilling platforms. Dangerous gases typically exist for at least 1000 hours per year.
Zone 1:Under normal circumstances,inflammable and explosivePlaces where gas mixtures may occur, such as non mining faces in coal mines, enclosed areas in petroleum and petrochemical industries (with ventilation openings), etc. The existence time of hazardous gases in this area is generally between 10-1000 hours per year.
Zone 2:Under normal circumstances,inflammable and explosiveGas mixtures are unlikely to occur and only occasionally occur for a short period of time under abnormal conditions, such as in non enclosed areas of petroleum and petrochemical plants (outdoors). The duration of existence of hazardous gases is usually ≤ 10 hours/year
（2） Classification of flammable and explosive dust environment areas
Zone 20:Places and containers where combustible dust continuously or frequently occurs during normal operation, and its quantity is sufficient to form a mixture of combustible dust and air and/or may form uncontrollable and extremely thick dust layers. For example, internal areas of certain dust containers, storage tanks, etc. The existence time of combustible dust is ≥ 1000 hours/year.
Zone 21:Places where combustible dust and air mixtures with combustible concentrations may be generated during normal operation. For example, places outside dust containers under specific conditions. The existence time of combustible dust is between 10-1000 hours/year.
Zone 22:Under normal operation, combustible dust and air mixture generally do not appear, only in abnormal conditions where combustible dust occasionally appears and only exists for a short period of time. For example, when the exhaust port of the dust bag filter ventilation hole malfunctions. The existence time of combustible dust is ≤ 10 hours/year.
It should be noted that the classification of hazardous areas should take into account factors such as the amount of flammable and explosive dust, explosion limits, and ventilation conditions. At the same time, when specific conditions are met, it can be classified as a non hazardous area.
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