I'm finishing the basement of a triplex condo in Chicago (townhouse style with a shared entry/common space with one unit). The developer didn't consider a future finished basement when it was it was converted to condos 20 years ago so there are conduit and pipes running under the joists.
Due to the low ceiling and the fact there would be soffits littered all over the ceiling, I plan on spraying the ceiling black (it actually looks surprisingly good). Before I do it, I want to make sure Chicago allows open joists in a living space.
There is fire resistant drywall on the ceiling near the water heater and furnace that will remain. Also, the new bathroom will have a finished ceiling. Joists have 16" spacing. The work is permitted so there will be a final inspection. Thanks!