The window wall system design is typically utilized on buildings where the structure conflicts with the exterior wall zone forcing the windows to run intermittently between floor slabs. The slabs are then concealed with formed aluminum panning or similar materials. The windows can be either factory or field glazed but typically come to the site pre-assembled.
The window wall design achieves a reasonable amount of performance against air and water infiltration in comparison with the curtain wall systems and does tend to surpass the curtain wall in acoustic ability (basically between floors). By using the panning as a gutter/flashing, the system can incorporate gutters on each floor and, subsequently, operate under the rain screen principle.