How is the actual maximum measured value of the defect’s circumferential length, denoted as B, determined?
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In the \"Regulations for Periodic Inspection of In-service Industrial Pipelines,\" the formula used to determine the safety classification of pipes in cases of local wall thickness reduction includes the factor of \"B being the maximum measured value of the circumferential length of the defect.\" For example, my tube has an original diameter of 90 mm and a thickness of 6 mm; the designed corrosion allowance is 2 mm. I measured 4 points on the outer surface at intervals of 90 degrees each, namely A at 5.5 mm, B at 5.2 mm, C at 5.2 mm, and D at 3.8 mm. Can it be considered that point D represents local thinning? So, according to the formula where “B is the maximum measured value of the defect’s circumferential length”, what is the value of B in this case?
Also, I would like to ask how 32.9 Mpa was calculated; it’s clear that the value of t isn’t known here! ?