How should one understand the scope of inspection 6 in GB20801?
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GB20801 pipeline inspection: As I understand it, pipeline inspection includes visual inspection, surface non-destructive testing (magnetic particle and penetrant testing), and internal non-destructive testing (radiographic and ultrasonic testing). The inspection levels for these 3 methods should all have 5. In 20801.5, under the inspection scope for 6, section 6.1.3 specifies the inspection level for pressure pipelines. Which inspection method is this level applicable to? Still for the above three. Then 6.3.2 provides further explanations regarding ray inspection. I now have a PN250 jacketed tube, with the inner tube undergoing 100% radiographic inspection. According to 6.1.3, the inspection level must be at least grade 1; according to 6.3.2, 100% of the radiographic inspections must meet grade 2 standards. However, I also checked other construction acceptance specifications, and those for jacketed tube construction, all of which specify that 100% radiography of the inner tube of the jacket is required. The inspection level is 2. Moreover, both the construction company and the special inspection institute believe that level 1 is too high, as it is difficult to operate in practice. I might have misunderstood clause 6 in 20801; please give me some guidance. Thank you.
Grade I is the inspection level; the corresponding inspection items are listed in Table 1, with 100% radiographic testing required； The acceptance criterion for radiographic testing is Grade II as specified in NB/T47013.2-2015.
That’s right; upstairs, they confused the grading levels for pipeline inspection with the acceptable grades for radiographic testing