Discussion on issues related to the non-explosion-proof areas around the furnace

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GB 50058 specifies that the area surrounding open-flame equipment is considered a non-explosive hazard zone; in accordance with the relevant provisions of SH 3038, this distance is 1.5 meters, meaning that the area within 1.5 meters around the open-flame equipment is a non-explosive hazard zone. According to the interpretation of GB 50058, since there is negative pressure inside the furnace, no explosive hazard zone is formed around the equipment. In my opinion, this is because the gas flow around the equipment moves towards the furnace, so combustible gases do not create an explosive environment; instead, they enter the furnace to burn there. So, what’s confusing is this: if there is a source of release in the normal sense within 1.5 meters of an open-flame device, then does that source still constitute an explosive hazard area? There are currently two interpretations: one is that the source of release in its conventional sense does not need to be classified as an area with explosion hazards, because the combustible gas that leaks out, due to the negative pressure inside the furnace, will enter the furnace and cannot accumulate to reach the explosive limit. Another interpretation is that this source of release still requires to be classified as a hazardous area for explosions; however, the overlapping area within 1.5 meters around the open-flame equipment is considered a non-hazardous area for explosions, while the non-overlapping areas remain hazardous areas for explosions.