Exit Size Opening

[RFreund]

This really is an architectural question so I apologize ahead of time.

What is the minimum size of an exit for a basement per IBC 2009 Chapter 10 for a commercial building?

Currently there are (2) exits - the stairs and one door as it is a walkout basement. They are filling in the walkout side with a path that would come up about half height of the wall so the door will be blocked in. Can a window service as an emergency exit.

I don't mean to 'crutch' on you guys with this question but Chapter 10 seems to be full of exceptions and I would like some 'confirmation' (maybe I should call an architect?)

EIT

http://www.HowToEngineer.com

 

[DST148]

We see fire escapes on old tenement houses in cities as a form of emergency egress. The landings are located at window sill level and windows serve as an exit. However, fire escapes were add-ons to existing tenements due to new building regulations.
Many times access to basement in commercial establishments is provided through vaults ( with hatch doors) which extend into sidewalks. But even there I have observed regular head room for steps that lead to basement.
One option could be providing a stair well at the exit that will lead to finished grade, so that normal exit door size can be maintained.
I think architect would be your best bet. Also try posting on IBC forum.