These hazards in the form of excess heat, moisture, harmful gases and vapors enter the surrounding air and blendes in, while its temperature, moisture content, gas content, dustiness increase. This involves changes in the chemical composition and physical properties of the air.
In order to maintain normal air parameters in the premises that meet sanitary and hygienic and technological requirements, we implement ventilation, which creates an organized air exchange-removes polluted air and supplies treated (heated or cooled, humidified or drained) fresh and clean air instead.
Ventilation in most cases can provide only acceptable sanitary and hygienic conditions in the premises. The air parameters, strictly defined by temperature and relative humidity, including optimal ones, can be reached by using air conditioning systems.
Classification of ventilation systems
Ventilation systems are divided into supply systems that supply fresh air to the premises, exhaust systems that remove dirty air from the premises, and air or air-heat curtains that prevent the penetration of cold air through the entrance or doors of buildings during the cold season.
Both supply and exhaust ventilation systems can be general and local type. General exchange systems are designed to supply and remove air evenly throughout the serviced room, to create an air environment with approximately the same parameters throughout the entire volume of the working area. Local exhaust systems remove the air in the places of formation of hazards from technological equipment, preventing the hazards from spreading throughout the entire volume of the room, polluting the entire air of the workshop. Local supply systems supply fresh air near workplaces, create an air shower or oasis – a restricted area in the production room where the parameters of the air environment meet sanitary and hygienic requirements.
Local exhaust ventilation is much more effective than central or general exchange ventilation, since it removes air from the places of formation of hazards with a higher concentration of them, does not allow the hazards to spread freely throughout the room, but such ventilation is not always feasible.
According to the method of air movement, all ventilation systems are either natural or mechanical.