Discussion on whether the space above the floating disk of an internal floating roof tank is Zone 0 or Zone 1?
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I have a question: According to GB50058, the hazardous areas in environments with explosive gases are classified as follows: Zone 0 – environments where explosive gas mixtures are present continuously or for an extended period of time; Zone 1 – environments where explosive gas mixtures may occur during normal operation; Zone 2 – environments where explosive gas mixtures cannot occur during normal operation, or where such mixtures exist only for short periods if they do appear at all. Then, which zone does the space above the floating roof of a floating-roof tank belong to? Zone 0 or Zone 1?
Reply to 1# bin7280: It should be Zone 2; at most it’s Zone 1, and Zone 0 only exists inside the tank. It depends on your usage to determine whether it is Zone 2 or Zone 1.
It should be Zone 1, but it doesn’t really matter much; there are no electrical devices here anyway
Reply to 3# xjfhqw: The classification of hazardous areas in explosive gas environments is not only relevant to the selection of electrical equipment, but also relates to many other aspects such as hot work management and fire safety management.
It should be Zone 1, after all, the internal floating roof prevents the material from evaporating.
Zone 1, but there’s really no need to discuss this; any hot work requires the tank to be emptied before work can proceed
Refer to Article 2.3.5 of GB50028: “For storage tanks containing flammable substances that are heavier than air, the classification of the areas at risk of explosion shall comply with the following provisions (Figures 2.3.5-1 and 2.3.5-2): 1. For fixed storage tanks, the space above the liquid surface within the tank, where no inert gas is present, is classified as Zone 0; for floating-roof storage tanks, the space within the range of movement of the floating roof is classified as Zone 1.”； II. The area with a radius of 1.5 m centered on the vent, as well as the pits and ditches beneath the floor in the explosion-hazardous area, are designated as Zone 1 ； III. The area within 3 m of the outer wall and top of the storage tank is designated as Zone 2 ； IV. When a dike is installed around the storage tank, the area between the outer wall of the tank and the dike, within a height range up to the top of the dike, is designated as Zone 2.
That regulation – GB50028 is the gas code, right?
Zone 0 is specified in the petroleum storage tank design codes
Article 2.3.5 of GB50058-92; Article 3.3.4 of the revised GB50058-2014.