Regarding the first flange of liquefied petroleum gas storage tanks
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I checked the relevant documents from the labor department; high-neck butt weld flanges have been used since 1999. But a 80-cubic-meter liquefied petroleum gas storage tank manufactured in 2002 was found; it seems to be from Jianghan, Hubei... There is a quality certificate from a pressure vessel factory under the Ministry of Chemical Industry, and the flanges shown in that certificate are not butt-welded flanges. Let’s discuss whether this situation is possible It turns out that the labor department exercised strict supervision at that time; there were few manufacturers, and on-site inspections were also carried out. I don’t think it’s possible.
If it’s not a butt-welded flange, then it is considered a violation.
High-diameter butt weld flanges should be used to meet the code requirements.
What type of flange is used in practice? If it’s just drawn on the diagram, it might be a typo.
It’s a flat-weld flange in reality, and I suspect this tank is fake.
Reply to 5# Ali Sees: Is the design team part of the manufacturer’s own design department? Generally, large design institutes are quite sensitive to changes in regulatory requirements, so they shouldn’t make such mistakes. It should be a design flaw. Flat welding is less resistant to stress compared to butt welding, but it’s not necessarily that dangerous; it was only because of past accidents that the requirements were changed. If you’re bold enough, keep using it; but to avoid risks, it’s better to cut it off and replace it.
It’s not allowed; high-neck butt weld flanges must be used, and radiographic inspection is required.