Ventilation is a process of exchanging the air in a building to provide proper microclimate for people who stay inside. Ventilation can be classified in many different ways, for example into natural, mechanical, supply and exhaust ventilation. No matter how we classify this process it is important to pick the one which is the most comfortable for the user.
Since when trends in architecture and construction became strongly steered on saving heat, companies has started to build more and more airtight buildings. To gain more control and minimalize heat losses , they started to use additional insulations and caulking which are the cause of an increase in a quantity of steam and concentration of pollution inside the building.
„Substances polluting indoor environment cannot be diluted as easily as outside pollution ” –claims the agency. Research done by EAP proved that the levels of indoor pollution in case of some substances might be 200 – 500 % higher than their levels in the outside air.
In this context, it is worth to consider how air quality can be improved in our everyday environment. A proper ventilation is essential to gain this aim. While spending time in different types of buildings (house, office etc.) we are constantly exposed to breathing in air pollution, such as dust, pollen, molds and fungi, as well as all types of toxins produced by building materials and furnishings.
The other factor is steam. Its concentration increases during everyday activities, such as taking a shower, doing the laundry or cooking. People exhale carbon dioxide all the time and the content of the steam in their breaths depends on what activities they are doing in particular moment.
An approximate intensity of steam emission while:
dreaming or relaxing: 50 g/h
doing soft work: 90 g/h
doing hard work: 150 g/h
dancing intensively: 340 g/h
taking a bath: 1000 – 1100 g/h
taking a shower: 1500 – 1700 g/h
drying clothes (one laundry): 2000 g/h
cooking (one meal): 1000 – 2000 g/h
It’s not easy to determine precisely which air pollutants are more and which are less harmful. It is the best reason to eliminate them all.
Because of health reasons and heat comfort, relative humidity should maintain from 30 to 65 % (at a temperature of 20 – 22 °C). At a temperature of 26°C, humidity should not exceed the limit of 55%. In case when air humidity is higher than 70%, conditions are conducive to expansion of fungi and mould.
Due to the way of air exchange, mechanical ventilation can be divided in:
general – it provides regular air exchange in whole room
local – effectively prevents from polluting the air in a place where pollutants are emitted. Local ventilation includes:
local air supply systems – they are used to create in particular place an environment which differs from general conditions in the room
air curtains – they are used to protect the interior from letting in cold air (in winter) or hot air (in summer) from the outside, for example when gates or doors in industrial or other public buildings are being opened frequently.
supply ventilation system – air is supplied by mechanical devices, but it leaks out naturally
exhaust ventilation system –in this case air is supplied in natural way and it is removed using mechanical devices
balanced ventilation system – here supply as well as exhaust is supported mechanically.