API 579/ASME FFS

[ronfrend]

CAn anyone tell me if the 2007 version of the API 579-1/ASME FFS-1 standard allows me to evaluate an Isolated Slag Inclusion (ISI as per API 1104) as an area of Local Metal Loss (Part 5). I know that porosity must be evaluated as Part 9 (crack) but I am unclear about the ISI.

Ron Frend

http://www.predicon.net

 

[SJones]

If it isolated and not linear, annex G.2 can be invoked. The question is: in service, what is the likelihood of defect propagation. For isolated, probably none (otherwise it wouldn't be allowed in the welding code anyway). Does what you have exceed the original welding specification?

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[ronfrend]

Thanks for the feedback Steve.

We are using API 1104 for evaluation of the pipeline (B31.4) and the defect is bigger than allowed. The flaw is 5mm x 4mm in an 8"pipe. Maximum width according to 1104 is 3mm.

From what I have seen in Annex G it appears to be background information without specifically saying that these flaws may be assessed. Even if they can be assessed it is really not clear which would be the best part.

We are trying to determine if we can use 579 or not with the intention that we could use the calculations to determine acceptance criteria for future monitoring of internal corrosion.


Ron Frend

http://www.predicon.net