API-ASME: 579: General vs Local Corrosion

[Rubje]

579 doesn't draw a clear distinction between general(part 4) and local corrosion (part 5)

Any guidance on how I can determine which part (4 or 5) to use depending on the situation?

thank you

 

[akpipelineengr]

Read 579 paragraph 4.1.2 and follow the decision tree in Figure 4.2. Basically, if you pass Part 4, you're fit for service. If you fail Part 4, evaluate using Part 5. Once you've done a few, you should be able to recognize the characteristics of the two types of metal loss.