Elec N Spec,
I see that you are an electrical inspector. Have you talked with the building inspectors? According to the ICC web site, the IBC has been adopted statewide in Mich. For the 2003 IBC, 1006.3 covers the requirement for emergency lighting and 2702.2.3 requires emergency power for the exit signs. For the 2000 IBC, the sections would be 1003.2.11.2 and 1003.2.10.5.