It avoids movement trough the corridors, lifts or elevatorsand clean zones. The smells dessapear (created by the accumulation of dirty laundry or waste in the plants). Minimum manipulation.
An discharging installation of gravity has included mailboxes or loading chutes on each floor, by the ones the bags are introduced. This ones are displaced vertically trough a metallic conductor, since the different points of the building plants untill the discharging zone situated in the inferior plant.