Stepped ventilation consists in adding ventilation ducts at the level of the ventilated storey next to ventilation ducts running from the lower floors of the building. Such a ventilation system makes it possible to enlarge the area of the rooms on the lower floors with the economic use of ventilation blocks. In this system, the supply air is taken from other rooms and from the staircase.
Full ventilation consists in bringing all ventilation ducts to the lowest floor. In the basement, inlet grilles or a transverse channel are used, which brings air into vertical channels, enabling the supply of fresh air to the ventilated rooms from the basement level. The projection area of the ventilated rooms is the same on all floors.