Modification of pressure vessels that have undergone manufacturing supervision and inspection
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Unit A, located in Tianjin, was responsible for the design and drawing preparation, while Unit B, based in Shandong, handled the manufacturing and inspection processes for use in Unit A’s project. The container in question was a vertical storage tank; the media stored within it were explosive substances such as ethylene and propane. The design pressure was 1.8 MPa, and the volume of the tank was 11.8 m3. Manufacturing and inspection were completed in 2013, but due to the cancellation of Unit A’s project, the tank remained at Unit A’s location without being registered. There is another project at unit A, where the medium used is compressed air and the design pressure is 1 MPa. This vertical storage tank wants to be utilized for this project, but its inlet and outlet fittings are DN25 flanges; they need to be changed to DN50 flanges. The modifications include: 1. The inlet and outlet sizes have been changed from DN25 to DN50 ； 2. The container medium has been changed from ethylene, propane, etc. to compressed air. Does this container modification need to follow the procedures for modifying pressure vessels? Unit A also has the qualifications to handle pressure vessels and wishes to carry out modifications on its own; how should this be done? Isn’t the most reliable approach for Unit A to prepare the renovation design drawings, which are then handed over to Unit B for the actual renovation and supervision? I don’t have any ideas at the moment; I hope fellow forum members can offer some guidance.
The most reliable approach is to consult the supervision and inspection department in the area where the container is used.
:Lol, I’m waiting for him to come. When he arrives, I’ll ask him and consult the forum members in advance
If the medium changes or the diameter of the pipe connections changes, the design agency must issue a change order; but can unit A carry out this modification? Assuming the original design firm no longer exists, who should be responsible for this design change?
1. Manufacturing and inspection cannot be carried out by the same entity； 2. Although you haven’t obtained a usage permit, since this is a modification procedure, you can submit it for inspection in accordance with the modification procedures.
By \"supervision and inspection,\" does the poster mean inspection by a third party or supervision and inspection by the local quality supervision agency? Third-party testing has little effect; it’s better to simply modify the design and manufacturing process ； After inspection by the local quality supervision station, the CS steel stamp was applied; this inspection is recorded in the official records. To carry out any modifications, it is necessary to obtain approval from the local supervision station, along with another inspection and recording in the records.
As long as Unit A meets the required qualifications, it can carry out the modification, and it is not necessary for the original manufacturer to do so. For the specific procedure, refer to the fixed capacity regulations.
This post was last edited by darren514 on 2022-10-14 at 15:30. The regulations state that modifying pressure vessels requires permission from the original design firm, and many inspection agencies emphasize this point; in other words, even if your company has the qualifications to carry out such modifications, you still need formal approval from the original design firm. So, you can simply follow the procedures for modifying pressure vessels, but due to the lack of registration, the specific process needs to be discussed with the regulatory authorities.
If Unit A possesses the appropriate design and manufacturing qualifications, it can directly make changes to the design documents and go through the necessary procedures for equipment modification, followed by carrying out the construction work and supervision inspections.
It has been manufactured, inspection is complete; making changes is useless