Regarding the classification of explosion-proof areas
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I’m currently working on a new project that includes a rotary kiln and a hot air furnace, which use pipeline natural gas for fuel. Today, the design institute suddenly informed us that there is natural gas inside the rotary kiln. Considering that natural gas may remain in the kiln after it is turned off, posing a risk of explosion, they proposed designating the areas surrounding the rotary kiln and the hot blast stove as explosion-proof zones. However, we believe that both the burners of the rotary kiln and the hot blast stove are equipped with safety valve assemblies; these valves will immediately cut off the gas supply upon shutdown. Additionally, there are blowers and induced draft fans to ensure proper ventilation. Therefore, we see no need to designate those areas as explosion-proof zones. Let’s discuss this further. One last complaint: after all the equipment has been ordered, this issue comes up again – I really feel like cursing.
Natural gas is a flammable and explosive gas, and should be handled in an explosion-proof manner. The area within 15 meters of the source of release is a blast-proof zone; it seems to be 15 meters, I’m not quite sure.
What project is that rotary kiln for?
According to Article 3.2.2 of the GB50058-2014 standard, areas with open flames do not need to be designated as explosion-proof areas. If there are valves or the like on surrounding pipelines, they shall be regarded as sources of explosive gas release and should be classified according to the protected areas.
It’s well-founded; I fully support it. You can definitely use these reasons to challenge this design institute!
Should it be placed indoors or outdoors? Generally, the explosion protection for natural gas is defined based on a 4.5m threshold
Using gas as fuel, any area where there may be leaks in the pipelines or containers is considered a blast-proof zone. When there is an open flame inside the furnace, it may not be a blast-proof zone; whereas when there is no open flame, it becomes a hazardous zone, or even Zone 0. Whether it is a deflagration hazard area is not determined by whether you install a safety valve or not; it is specified by standards and regulations. You should first curse yourself – why wasn’t the issue of explosion protection considered from the beginning of the project, when it’s clear that combustible gases would be used?
Dude, why would I curse at myself? You might not have seen it clearly, or you may not be familiar with the process for new projects. It’s a new project, and the design institute will issue a specification document for ordering the equipment. This document doesn’t mention such requirements; only after we place the orders do those requirements come up, forcing us to communicate with the equipment manufacturers to request the use of explosion-proof motors. And you also said that since there is an open flame inside the furnace, it doesn’t have to be a blast-proof area; we use a direct-fired rotary kiln, and according to your theory, it doesn’t need to be classified as a blast-proof area.
The view expressed by Haiyou on the 9th floor is correct; however, both parties share equal responsibility. The design institute made mistakes in the specifications it provided, so it should bear half of the responsibility. But as the owners, didn’t you guys review the specifications given by the design institute? How could such an obvious mistake go unnoticed? You should also bear half of the responsibility