Classification of the main compression elements
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There is a device whose shell is made of 168 diameter pipes, with the two ends connected by DN150 butt-welded flanges; each flange is equipped with a blind plate with openings. I would like to ask: based on the regulations regarding the main pressure-bearing elements in the code, please answer the following questions. 1. Are the 168 diameter pipes used for the shell considered the main pressure-bearing elements? 2. Are the DN150 flanges at both ends of the pipe outlet considered primary pressure-bearing elements? Should it be called a pipe flange or a equipment flange? 3. If the DN150 flange is a primary pressure-bearing element, then is the flange cover with the matching opening also a primary pressure-bearing element? (Open holes in the flange cover and weld a pipe fitting and a flange to it respectively)
Well, the OP’s question is really great; I wonder how the leaders at the headquarters will explain it, haha.
【1. The 168-mm tube used as the shell should be the main pressure-bearing element, right?】 】Yes.
【Are the DN150 flanges at both ends of the pipe outlet considered primary pressure-bearing elements?】 】Yes.
【If the flange of DN150 is a primary compression member, then is the flange cover with the matching opening a primary compression member?】 】No.
It seems a bit far-fetched to use such a simple device, with the few components you mentioned as the main load-bearing elements, but it’s not difficult to build.
It seems a bit far-fetched to use such a simple device, with the few components you mentioned as the main load-bearing elements, but it’s not difficult to build.
1. The 168 pipe is the main pressure-bearing element； 2. The DN150 flange is a primarily compressive component; it belongs to the type of flange used in equipment ； 3. The mating flange covers are also the main compression elements. Because here it should be considered a flat cover.
First, check whether this small device meets the requirements of Article 1.3 in TSG 21-2016; if it does, then it is a primary pressure-bearing component. Otherwise, how can it be considered a primary pressure-bearing component?
First, it is necessary to determine whether it falls under the category of pressure vessels. If it does not meet one of the criteria specified in Article 1.3 of TSG 21-2016 (i.e., having a critical inner diameter), then it is not considered a pressure vessel, and discussing the main pressure-bearing components is meaningless in such cases. Check again whether it belongs to a simple pressure vessel. In the case of a pressure vessel, the 168 tube sections, the DN150 flange (which can be considered as the equipment flange), and the matching flange covers shall all be the primary pressure-bearing elements.
This post was last edited by Pinocchio on 2017-9-29 at 11:41. For pressure vessels falling under the scope of regulatory requirements, the certificate of manufacture always includes data on the main pressure-bearing components. The pressure vessel shell, as well as the flanges and flange covers that are directly connected to the shell, cannot be considered as nozzles, even if their diameter is less than DN250.