Agreed, we REALLY need to get a clarification about this conflict soon. I don't care if IBC, NFPA or another agency takes the reigns, but we need to get rid of this ambiguity.
In Chicago, where they're usually absolutely anal about emergency lighting levels, they interpret IBC1006.1 (The means of egress, including the exit discharge, shall be illuminated at all times the building space served by the means of egress is occupied) like this...
During the day, the exterior discharge is illuminated by the sun; during periods of darkness, the exterior discharge is illuminated by the lights. The lights can be switched off when there's enough natural light, but it has to be by a failsafe photocell in/at the fixture.
I can design whatever they decide they want, but I'm getting tired of ending up in the trick bag when different jurisdictions have different requirements.
