Once, air supply was partially secured through the areas of the building structure, which were not airtight, through which the fresh air flowed in.
The outside walls of individual multi-apartment buildings have built-in channels for the supply of fresh air.
When renovating buildings, replacing windows, performing works to ensure heat insulation and airtightness of the building, as well as various indoor repairs, areas lacking airtightness and air supply channels are often closed with different solutions, resulting in a lack of natural supply of fresh air.
Air circulation in housing usually takes place through open doors, hallways or other gaps.
When replacing indoor doors, it is preferable to leave a small gap under them so that even in closed condition the air between rooms can be exchanged.
If doors are closed tightly, an overpressure condition may build in the room where air supply is provided, while the rooms with air exhaust channels will be in a low pressure condition.
It can be felt as a resistance in the process of opening or closing the door.
Air exhaust channels in multi-apartment houses and private houses are installed in rooms with a high risk of humidity, such as the kitchen, bathroom and toilet.
This is done to ensure that the excess humidity and odours that occur during cooking or washing do not spread in the entire housing, but are extracted from it.
In multi-apartment buildings, air, through exhaust channels, enters the vertical air extraction shafts, which discharge the extracted air onto the roof of the building.
The air flow is ensured by the difference between the height of the room and the roof outlet.
The higher the air exhaust shaft is located on the roof, the better the air draught would be.
Similarly, external conditions, such as wind, also improve or worsen the draught. If the natural ventilation of the building has insufficient draught, deflectors should be installed on air outlet channels on the roof.
They look like pipe ends of an increased diameter, which intensify the draught of the ventilation system depending on the direction of the wind.
The natural ventilation exhaust channels must not be closed or fans not working 24 h a day must not be installed in front of them, as there is no air exhaust at the time, when the fan does not work and ventilation in the housing does not function.
The same applies to natural ventilation exhaust channels in the kitchen.
Apartments in multi-apartments, where gas cookers and heating equipment are used, should not interfere with the natural ventilation system.
Any intervention in main structures of the building, such as reconstruction of natural ventilation without coordination or connection of a stove hood to the exhaust channel in the kitchen, is not allowed and should be regarded as arbitrary construction.
