Internal floating roof tank
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Question: What is the lowest allowable height to which the floating disk of an internal floating roof tank can descend? In the \"HG21502.2-1992 Series of Steel Vertical Cylindrical Internal Floating Roof Storage Tanks\", there are two heights: an operating height of 900 mm and a maintenance height of 1800 mm; however, it is stated that the minimum height is 1600 mm and the low liquid level is at 1800 mm. I’m not sure which one is correct now; I hope those with experience in working on internal floating roof tanks can help clarify this. Thank you!
Operating height of 900mm, maintenance height of 1800mm
Refer to standard SH/T3194-2017
First, check what the height of the floating platform columns is. Currently, it is generally 1800 mm; if that’s the case, even when the material inside the tank is empty, the lowest position of the floating disk remains around 1800 mm. In principle, during normal operation of the tank, its liquid level must not drop below the height of the floating disk. If operation at a low liquid level is necessary, it is important to control the flow rate and pressure of the medium; otherwise, static electricity may be generated, leading to safety accidents.
Which standard are you referring to? The standard I saw specifies an operating height of 900 mm; in my understanding, the minimum height is also 900 mm
Depending on the structure of the floating pad, adjustable legs can be used. One is the operating height, around 900, and the other is the maintenance height, around 1800. But in reality, these heights aren’t very useful, as adjusting the height of the legs is extremely troublesome, making it not worth the effort.