Question is in reference to "7. Provide daylighting at each floor/roof level of the stair(s) using either windows and/or skylights of at least 8 square feet (1 square meter) in size.

I'm working on a 2 story commercial project that has a main spiral staircase connecting a 1st flr lobby and 2nd flr cafe with a large curtain wall spanning almost the entire height of the staircase (does not continue to the roof). My gut tells me this would be compliant with the feature, but I'm looking for confirmation that it is compliant despite not accessing the roof (and not having a skylight). 

I also wanted to confirm that these requirements can be for a single main staircase (not all staircases in the building) - my gut says yes, but wanted to double check. 

Thank you!