with very large angles the external coating is usually cracked in the ASME B31.8 there is a table that indicates the degrees / PD but does not specify if it is for coated pipe
juancd200914,
I think you really mean the "bending radius" and not the "bending angle"?
A "hard" coating, inside or outside, the pipe may have problems with any bending radius.
A "soft" (or elastic) coating, inside or outside the pipe will tend not to have problems with a bending radius.
If you can bend your pipe without damage to the coating then the angle of the bend will not matter.
Sometimes its possible to do all the right things and still get bad results
It's always best to define what you mean and references so I assume you mean table 841.2.3-1.
This only relates to the steel pipe and is based, I believe, on a maximum strain in the outer edge of the pipe of 2%.
Now whether your coating can withstand a strain of 2% no one would know. some coating e.g. FBE, usually can. Some harder more brittle epoxy or glass type coatings might not.
Despite that table, most pipeline designs I see use 40D as a standard cold bend radius for all diameters and this has become an effective industry standard. So for smaller pipes it is less strain, but larger pipes it's getting close to the 2% limit.
Does that help?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
