The building is a typical U-shape. At the open end of the "U" at each story is an open, connecting bridge. Centered at the bridge is an exterior (not enclosed) stairway. I don't see where this would be a problem, but the issue has to do with the fire resistance of the bridge structure. Would the structural frame supporting the first bridge be required to have a 3-hour fire-resistance rating (for Type IA) and the rest of the structural frame have a 1-hour rating (for Type VA)? And, would the bridge at the second story (i.e. in line with the 3-hour horizontal assembly) also be required to have a 3-hour rating? Or, could it all have a 1-hour rating?