Cross section openings
The supply air usually flows from the “supply air room� through the hallway, entrance or corridor (cross section rooms) to the exhaust air rooms, such as bathroom, WC, kitchen.
Air supply openings, such as door gaps, cross section openings in walls or cross section grills in doors, should be provided to enable air exchange between these rooms. Usually the doors are shortened at the bottom to create an air gap of 5-10 mm, for example. It would be ideal to have an outlet opening from the supply air room at the top and to allow the air to enter the exhaust air room at the bottom.

