Using the new API 579-1/ASME FFS-1 Code

[chemdude]

Hello,

I am doing research in rerating of corroded pipelines. So far I have used the DNV RP F101 and B31G code to calculate the MAOP using the measured anomalies in the pipe. However, I still have to use the new API 579 code, released June this year (API 579-1/ASME FFS-1, JUNE 5, 2007), but this is turning out to be a challenge for me. I was hoping can anyone guide me in how I can use this code to measure the remaining strength of the pipeline as this code is not as straight forward as the DNV and the B31G codes. I would appreciate anyone's input. Thank you.

 

[XTZ123]

API RP 579 is not that difficult to use if you can satisfy the accepatnce criteria for the identified damage mechanism.
If you are able to supply more details of the system you are analysing I may be able to advise further.

 

[chemdude]

Thanks XTZ123, the system I am analyzing is an offshore pipeline having the following parameters:
D: 20in, MAOP: 129bar, WT: 12.7mm, and grade of X65.

There are roughly 15 anomalies, all internal corrosion defects located at the 6 o'clock position, for instance one of the defects has the following data:
Axial(mm): 588; Circ(mm):94mm and Depth (%WT):48

I have been able to determine the MAOP using DNV-RP-F101 and the ASME B31G code, but the API RP 579 seems a bit difficult for me to understand. I have tried to read Section 5 of the code (Local metal loss) but it just jumps around the whole code without clarity on my part. All I was hoping for is a guide as to how to use the code maybe depicted in an example if possible.

I would be most grateful for any assistance.

Many thanks, XTZ123!

Looking forward to your reply.

 

[XTZ123]

Do you need to estimate the remaining life for the pipeline under its current operating conditions or do you want to re-rate the line?

 

[chemdude]

I want to rerate the pipeline.