Section 310.10, FPN:

Would tubing be considered on the rooftop, and what does "close proximity" mean?

I think the rooftop reference is entirely misplaced. If that raceway was running adjacent to a south facing wall or driveway it would be subject to the same heating effects.

I agree with gfretwell. Why not propose a FPN that says something like "elevated temparatures can be experienced when installing raceways above a massive steam boiler". I mean, doesn't anybody who's ever been on a rooftop already know that it's hotter than hell up there?

Joe, to answer your question, I don't know. If this ever becomes a requirement I will try to analyze the language a bit more. FPN's are susposed to help interpretation, not hinder it. When I see confusing language in an FPN, I ignore it

LMAO