i am leaing more to bob's answer there .
yes any pipes included the ell sweep[s] if 24 inch or less but i am still consering about the abilty of heat build up in there.
and for short pipe nipples 24 inch or less.
I have see few place some peoples did use 24 inch pipes and jamed many romax[s] wire in the pipe and i have one call not too long ago and have to replace bunch of romax wire they were brittle in few spots.
Really IMO,, i dont know if they did change the code or not about derating the wires in the nipples at all but i wish they change the length limit to more like 4 inch or less that can clear up some of the mess we have to deal with it ..
merci , marc