Quote Originally Posted by gadfly56 View Post
Well that is certainly true. The problem is, NFPA 72 doesn't really deal with this sort of thing. Is the skylight constructed with glass walls for its entire depth, or is it more like a light well, with a glass "lid" and maybe 4-6" of vertical glass at the very top and gyp board sidewalls?
The installation in my original post, does not require smoke detectors by code. Smoke detectors were installed because it was owner's preference. Therefore based on the code citations below I think smoke detectors wouldn't be required at the top of the skylights/light wells.

NFPA 72 says the following* Nonrequired Coverage.  Detection installed for reasons of achieving specific fire safety objectives, but not required by any laws, codes, or standards, shall meet all of the requirements of this Code, with the exception of the prescriptive spacing criteria of Chapter 17.  Where nonrequired detectors are installed for achieving specific fire safety objectives, additional detectors not necessary to achieve the objectives shall not be required.