Classification of explosion hazard zones in semi-enclosed areas
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1. The composition of the process gas is: CO 5.44%, H2 53.63%, N2 32.23%, CH4 5.05%, CO2 3.65%； 2. The equipment area is the boiler area, which is not a explosion-proof zone. Process valves are installed in a semi-enclosed area with walls on three sides, an open side, and an exposed top ； 3. There are glass windows and a door on the wall. For specific on-site details, please refer to the attached photos and schematic diagrams. Dear sea friends, with this layout, can this area be classified as Zone 2 for explosion protection? Do the glass and doors on the wall need to be sealed off? Thank you all.
With such an arrangement, this area cannot be simply classified as Zone 2 for explosion protection; a specific analysis is required. According to GB 50058-2014 \"Standard for Explosion-Proof Electrical Apparatus in Explosive Atmospheres\", the classification of explosion-proof areas requires consideration of factors such as the possibility of gas leakage, ventilation conditions, and building structure. The proportion of H2 in the gas composition is high, posing a significant explosion risk. Given the structure with walls on three sides and an open side, in the event of a leak, hydrogen may accumulate in this semi-enclosed space, increasing the risk of explosion. If glass windows and doors can be closed and provide adequate airtightness, it reduces the risk of gases leaking into the outside environment; however, if airtightness cannot be ensured, additional sealing measures may be necessary. Whether a specific area should be classified as an explosion-proof zone and whether sealing is necessary should be determined based on the specific conditions at the site and relevant professional regulations for explosion-proof electrical equipment. It is recommended to consult professional explosion-proof electrical engineers or experts in this field for a detailed assessment. .
1. The composition of the process gas is: CO 5.44%, H2 53.63%, N2 32.23%, CH4 5.05%, CO2 3.65%； 2. The equipment area is the boiler area, which is not a explosion-proof zone. Process valves are installed in a semi-enclosed area with walls on three sides, an open side, and an exposed top ； 3. There are glass windows and a door on the wall. For specific on-site details, please refer to the attached photos and schematic diagrams. 1. The content of combustible and explosive components in this mixture exceeds 60%, and the hazard levels for carbon monoxide and hydrogen are IIC; depending on the likelihood of such an atmosphere occurring, it may fall within Zone 1 ； 2. Semi-enclosed areas, where in the event of a leak, leakage is difficult to occur, and there are no ventilation systems (forced ventilation) in lower areas ； Although the boiler area is operated under negative pressure, the electrical equipment there, which is not located in an explosion-proof zone, is not explosion-proof; therefore, when flammable gases leak, they could serve as a source of ignition ； 3. Glass windows and doors do not play a significant role in preventing the escape of hazardous gases. It’s better to discuss this with professional security technicians; such security issues are not something that you or other users on the forum can handle on their own.
This post was last edited by timwangwt on 2024-1-17 11:08. Thank you for your answer. I’m asking this question to see if anyone has similar design or project experience, as well as any solutions they might have; it’s to draw on everyone’s suggestions and opinions, not as a direct basis for making a final decision. Additionally, my question regarding whether glass windows and doors should be sealed is aimed at preventing the spread of combustible gases into the non-explosion-proof areas within the boiler room in the event of a leak, thereby avoiding accidents caused by those non-explosion-proof devices acting as ignition sources.
For this issue, you need to check whether there are any leakage points. If not, there is no need to designate it as an explosion-proof area; if there are leakage points, then check whether the radius covers this area
There are process valves, which are treated as secondary release sources.
It’s not clear what exactly this process valve is. If it is confirmed to be a leak point, an explosion-proof zone needs to be designated
Combustible gas components are lighter than air, and the explosion zone in Area 2 is only 4.5 meters wide. The flow rate of the equipment or valve assembly is not greater than 38 L/S; it is also considered a secondary release source, with an explosion range of 4.5 meters. Indoors, there is no need for explosion protection, nor is it necessary to modify the walls.
Where is the project? Cooperation in design is possible; P
This really needs to be studied by a design institute