Qualification of rooms for handling combustible dusts
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The room where combustible dust is unpacked and fed in can now be designed as a Class B room. Downstream of the silo, a screw is used to transport the powder to the mixing tank to form a suspension; therefore, does the room where these downstream operations take place need to be classified as Category B? It only involves operations with dust in enclosed equipment.
According to the \"Technical Guidelines for the Assessment of Hazards from Flammable Dusts in Chemical Enterprises,\" the classification of rooms where flammable dusts are handled should be determined by taking into account factors such as the degree of dust generation, accumulation, and dispersion within the handling area, as well as the operating mode of the equipment. For the dust-handling room you described, since the powder is conveyed by a screw conveyor downstream of the silo, the dust remains within enclosed equipment and no open handling takes place; therefore, this room can be designed as a Class B room. It should be noted, however, that if dust may scatter or spread into the room during the operation of the mixing tank, it is necessary to re-evaluate the flammable dust classification of that room based on the actual conditions. It is recommended to conduct a comprehensive assessment and control to ensure operational safety. -
Based on the information you provided, I believe it may not be appropriate to design the room where the downstream operations take place as a Class C room. Since the situation you described involves dust being present inside enclosed equipment, the dust does not spread directly into the room; instead, it is transported and handled through those enclosed devices, so the risk is relatively low. If the room is designed as a Class B room, it is already sufficient to ensure operational safety. If you have conducted a thorough risk assessment and determined that the room can be designed as a Class C room, then you may consider designing it as such. However, it is important to note that the risk assessment must be very rigorous in order to ensure the safety of operations involving combustible dusts. -
When were these guidelines issued? I haven’t seen them
The \"Technical Guidelines for the Hazard Assessment of Flammable Dusts in Chemical Enterprises\" were issued by the Chinese Society of Chemical Engineering in 2014. This technical guideline is a guiding document for assessing and controlling the hazards of flammable dusts in chemical enterprises, and many companies refer to it when carrying out their work. -
I can’t find any information online. Do you have an electronic version or a link? Learning*, thank you!
If you need information regarding the assessment of the hazards associated with combustible dusts, you can refer to **relevant regulations and standards, such as the ‘Regulations on the Environmental Management of Chemicals’, the ‘Regulations on the Safe Management of Hazardous Chemicals’, and the ‘Standards for Fire Risk Assessment in Industrial Enterprises’ -
Dust in enclosed equipment can be classified as Category C.