Flexible connection issues for inlet and outlet pipelines of above-ground flammable liquid storage tanks
Thread Content
Current petrochemical standards specify as follows: \"Code for Fire Protection Design of Petrochemical Enterprises\" GB50160-2008 (2018 edition), Section 6.2 – Above-ground storage tanks for flammable liquids； 6.2.25 “The inlet and outlet pipes of the storage tank should use flexible connections.” However, in practice, according to various **expert inspections, regardless of the size of the storage tank or the diameter of the pipes ； It needs to be connected with a flexible metal hose ； This is absolutely unbelievable! I basically disagree with the so-called approach of designing based on pipeline routes or using flexible supports (in reality, it’s not possible to provide a basis for calculating flexibility in such designs). What do you all think are the solutions to this issue?
This cannot be cracked; our management is a bureaucratic system. Generally speaking, if you raise your objections in person during the inspection at that time, you are showing disrespect to the experts in charge, and therefore you must make the changes ； Suggestions made after the fact may still not be implemented.
Installing flexible connections is intended to prevent the storage tank from sinking and causing the inlet and outlet pipelines to break, which would lead to oil leakage. The purpose of this measure is sound, and it’s something that is done in design work in practice. I’m not sure what specific problem you are facing
The original intention behind the standards was not wrong, but since there was no specific quantification； It is often considered to be a misrepresentation! For example, for flammable liquid storage tanks that have been in use for over 10 years with a capacity of 50 M3, it is now required to install flexible connections on all inlet and outlet pipelines. However, inspections only take into account metal hoses, without considering the diameter of the pipes. What do you think is the problem with this?
The specifications include a provision regarding flexible connections, and we have no choice but to comply with it. The reason why only metal hoses are accepted is likely due to considerations related to strength. I’m aware of the option of using elastic support brackets, but this method isn’t mentioned in the specifications; I’ll see if I can discuss its use with the inspectors. After all, they have the imperial sword with them: lol
In fact, many standards today have similar issues; the intentions behind these standards are good； However, not every inspector is able to fully understand the background of the regulations, which leads to misunderstandings and creates chaos. Issues such as the installation of dikes, and the installation of emergency shut-off valves on storage tanks – regardless of the size of those tanks – require that such devices be present during inspections; they must be installed in accordance with standards (Especially some **documents also just take a few standard sentences directly) Sigh! It’s so tough to survive in the chemical industry!
It’s not easy to conduct inspections either; it’s not sufficient to find no problems, and corresponding standards are necessary. Any major hazards identified must also be reported
Actually, what is referred to here is a flexible connection; it’s not necessarily necessary to use metal hoses. In fact, by using elbows in the pipelines at the bottom of the tank and elastic supports, a flexible connection can be achieved
Yes, the key issue is that the tanks have been in use for 10 years now, so it’s not possible to provide flexible design data
In developed countries abroad, storage tanks, especially those for chemical products, do not use flexible metal hoses. The reason is that the flexible metal hose is a consumable item that needs to be replaced after a few years, and when it is replaced, large amounts of liquids such as benzene, phenol, and alcohols are released. Chemical products should minimize such unnecessary pollution, and sedimentation is handled by using supports. Moreover, in most of our plants, the first valve is not an emergency shut-off valve; in the event of a fire, it is not possible to close the main valve. Even if subsequent control valves are closed, metal hoses are most prone to breaking in such situations – they will rupture as soon as heat is applied, leading to another major disaster. Metal hoses are not a good choice for use in flammable liquid storage tanks.
Thank you! I had also considered this relatively simple and effective approach to improvement before. But adding more later involves design data ； How to meet the requirements for settlement and seismic intensity ； Plus, with the pipelines connecting the storage tanks, no one currently working on this rectification can provide the design data! Mainly, I’m complaining that there should be some standard specifications for the sizes of storage tanks and pipelines; or it would be ideal to have examples of flexible connections provided from a professional design perspective ； So as to make the inspections and corrective actions more targeted! Including things like installing cut-off valves – it’s a one-size-fits-all approach!