Besides special buildings such as atriums, undergound buildings and high rise buildings, I see nothing in the IBC that requires detection for garden variety group "B" occupancy building.
A manual fire alarm system is required for group "B"'s with an occupant load over 500 persons or more than 100 persons above or below the highest level of exit discharge, there is also an exception for this for a sprinklered building.
I have never laid eyes on the NFPA 13 or NFPA 72, so they might contradict what I'm saying.
The thing about a group "B" occupancy, from a code point of view, is that provisions are quite lenient compared to the other major occupancy groups. For example, a typical office building never requires sprinkler sytems, unless for specific reasons (such as area increase, atrium, high rise, underground, etc.).
I hope this helps you Ron, but I'm not sure that it does