Inspection issues for vertical storage tanks
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I need help. I am currently working on a vertical storage tank, which has a total of 8 layers of wall plates. The thickness of the wall plates from the 8th layer down to the 4th layer is 8 mm, while the thickness of those from the 3rd layer down to the 2nd layer is 10 mm. The bottom layer of wall plates has a thickness of 12 mm. As described in 50128, the inspection ratio for T-joint cracks in wall panels with a thickness of 10 mm or less is 25%. Do I only need to photograph 25% of the zigzag seams on layers 2 to 8? Seeking advice from experts
This post was last edited by gjn1970 on 2019-5-5 at 15:04. Construction shall be carried out in accordance with the specifications for vertical cylindrical welded steel storage tanks GB50128-2014 and GB50341-2014. Radiographic inspection shall meet the following requirements: 100% radiographic testing of the longitudinal welds on the bottom and the lower ring of the tank wall, with grade III considered acceptable； 20% radiographic inspection of the circumferential welds on the bottom and lower ring walls, as well as the longitudinal welds on all other rings; grade III is considered acceptable ； The remaining ring welds are inspected at 2%, with grade II considered acceptable ； 100% radiographic inspection of all T-joints on the tank wall, with grade II as the acceptance standard ； 100% magnetic particle testing of the inner and outer corner welds between the bottom ring wall plate and the tank bottom, with grade I as the acceptable standard ； 100% radiographic inspection of the butt welds on the bottom edge plate of the tank (outer edge at 300 mm), with grade II as the acceptable standard ； 100% magnetic particle testing of the root and surface of the T-joint weld on the tank bottom plate.
What was said upstairs is very good; construction should be carried out strictly in accordance with the specifications for the construction of vertical cylindrical welded steel storage tanks, namely GB50128-2014 and GB50341-2014. :)
Hello, I have checked the standards 50128 and 50341 – for tank wall plates with a thickness of less than 10 mm, should 25% of the T-joints be subject to radiographic testing? Which standard does the 100% radiographic inspection of all T-joints you mentioned rely on?
Follow the specifications; if high standards are required, use 100%, and if lower standards are sufficient, 25% will also work.
Then there’s no problem. If the requirements are high, then separate technical specifications will need to be developed for the design
Our company’s storage tanks are subject to 100% flaw detection, with the sampling rate determined in accordance with relevant standards；