What constitutes "floor area being ventilated" in a typical multifamily unit ?

[Ryan Schultz]

For the following excerpt, what constitutes "floor area being ventilated" in a typical multi-family unit?

402.2 Ventilation Area Required
The minimum openable area to the outdoors shall be 4 percent of the floor area being ventilated.

Would all the rooms in the unit be considered the 'floor area being ventilated'?

Or can certain areas like hallways/bathrooms/closets be removed from this area?

Thanks, Ryan

 

[ADAguy]

Those rooms with windows? as in habitable rooms.