The difficulty in using API 570 for pipelines is that as afar as I can see they are based on being able to access the pipe material for visual and NDE such as UT, X ray etc.
Buried pipelines tend to make that quite hard.
section 9 of API 570 addresses buried piping which is similar to pipelines.
Your question though is quite vague and I don't really understand where you're coming from?
Are you looking for ways to interpret metal loss data? Then go for ASME B31G, even though it's a bit conservative I think.
But you need specialists for this task.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Your profession (Petroleum) implies the pipeline is for oil..
I will suggest you to develop in-house company standard for in service inspection ,and probably should address; pipeline repair,pipeline protection, Corrosion Control , row and site maintenance
,pipeline pigging,valve maintenance requirements, SCADA and system automation ....etc...
You may look to API 570,API 579-1 FFS-1, for specific items..