Critical Defect Length (CDL)

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References:
AS2885.1 Clause 5.5.4 Critical defect length
AS2885.1 Clause 4.9 Provisions for high consequence areas 
AS2885.1 Clause 4.9.2 No rupture

"No Rupture Pipe": for new pipelines you design for 1.5xCDL - OK. But for assessing existing pipelines, shouldn't having minimum hole size > CDL satisfy no rupture?

(Peter Tuft) There isn't any difference between existing and new pipelines in this context. The 1.5 factor is a safety margin reflecting uncertainty in the CDL calculation as well as uncertainty in other data such as the actual tooth size (because there is not a perfect correlation between machine weight and tooth dimensions).


If the equivalent hole diameter was previously used for defect length assessment rather than the base length, should the pipeline be retrospectively assessed?

(James Czornohalan) I'd suggest you re-do the calculations, and then use those calculations to make a judgement call if you want to wait for the next scheduled SMS or re-assess immediately.