Code varies by jurisdiction, but stupid knows no limits.
I use the IRC as a starting place since it is the fall back code for the state on new construction warranties and is a pretty good bet on being accepted by most. Besides, I can't be an expert on all the codes and variations that are within 5 miles of my house, much less for the entire state.

As has been repeated here many times, code is the minimum. I will often recommend something that is not "code", but it is a good starting place.

As far as your specific question about a door, there may well be a more stringent requirement or no requirement at all, but I will write up a hollow core door or one with a window every time, code or not.

__________________
Jim Luttrall
Mr. Inspector.net, Inc.
Allen, Texas 75002