Urgent! Can a storage tank have an opening on its circumferential weld?
Thread Content
Some tanks require the addition of manholes, with capacities ranging from 1,000 to 10,000 cubic meters. The location of these openings is exactly between the wall panels on the first and second layers. I checked the design specifications but couldn’t find any relevant provisions; is it acceptable to have openings at the circumferential welds between different wall panels? If it doesn’t work, which specification specifies the reason? What needs to be done if the row is used? Is it sufficient to simply meet the Grade II requirement for 100% radiographic testing?
There are no issues with the pressure vessels, and there will be no problems with the storage tanks either. If not specified in the standards, the design shall be determined independently; as a reference, radiographic testing can be carried out on the circumferential welds of pressure vessels and manway accessories.
Allowed. Inspection within the specified range is sufficient
Is it really just a simple check? Is opening holes in sewn and unstitched areas really that simple to handle?
Is the difference in testing between seams and seamless openings really just a simple matter of testing? Just handle it directly and that’s it?
The last edit to this post was made by nj1952 on 2017-7-14 at 11:21. Article 10.2.6 of GB 50341-2014, \"Code for Design of Vertical Cylindrical Welded Steel Oil Tanks\", specifies the distance from the outer edge of the fillet welds at the openings in the tank wall to the center line of the longitudinal welds on the tank wall. (1) When the thickness of the tank wall is not more than 12 mm, or when stress-relief heat treatment is carried out after welding the connections to the tank wall, the distance from these fillet welds to the longitudinal welds should be no less than 150 mm； The distance from the circumferential weld shall be not less than 2.5 times the nominal thickness of the wall plate, and not less than 75 mm. (2) When the tank wall thickness is greater than 12 mm, and no stress-relief heat treatment is carried out after welding the nozzles to the tank wall: it shall be greater than 8 times the larger weld leg size, and shall not be less than 250 mm. Article 10.2.7 of GB 50341-2014, \"Code for Design of Vertical Cylindrical Welded Steel Oil Tanks\", also specifies requirements regarding the distance from the opening in the tank wall to the lowest point of the tank wall. The provisions of GB 50128-2014 \"Code for Construction and Acceptance of Vertical Cylindrical Welded Steel Storage Tanks\" are the same as those of GB 50341-2014. I understand that for openings in large storage tanks, it is entirely possible to avoid welds in the layout design.