【Daily Question】Registered Safety Engineer 2021.10.23

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The classification of hazardous areas in explosive dust environments should be determined based on factors such as the amount of explosive dust, release rate, concentration, and other characteristics, as well as practical experience from similar facilities in other enterprises. Among the following zones classified for explosive dust environments in flour production workshops, which one is incorrect? A. The interior of the screening machine’s container is Zone 20. B. The area around the sampling point is Zone 22. C. The outlet where flour is packaged into bags is Zone 22. D. The interior of the rotary vacuum cleaner is Zone 20. Answer: C. Explanation: Zone 20 includes areas inside equipment such as dust containers, cyclone dust collectors, and mixers. Zone 21 includes areas adjacent to the outside of the equipment, such as near the outlets of dust containers that are opened frequently and near conveyor belts. Zone 22 includes the area surrounding the dust bags, sampling points, etc.