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Ventilation is a primary engineering control available to
reduce the concentration of gases, dusts, vapours,
smoke, and fumes in the air. Dusts, fumes, vapours, and
gases in the air are drawn into the ventilation system and
carried to the collecting device by a pressure gradient
created by the fan. The fan must have sufficient power to
overcome the resistance to air flow created within the
environment.
General ventilation is not suitable to control
exposure to toxic substances because these systems actually
spread the contaminant throughout the workplace before
exhausting it.
General ventilation systems are used primarily to control
temperature and humidity, to remove odours, and sometimes to
remove traces of toxic substances and micro organisms emitted
from carpeting, panelling, furniture and people.
Ventilation is to design a system capable of restricting the
high-level temperature rise inside the building to a
pre-determined level above the prevailing outside ambient
temperature by creating a minimum air change rate per hour
These systems provide positive, fresh air movement to
central working areas within the building that in turn
provide evaporative cooling for the operatives at their
respective workstations. Due to the relatively low capital
cost, in relation to the highly desirable conditions
achieved, this is the most common approach within industrial
buildings today.
For general industrial ventilation systems, clean rooms or
process ventilation can be provided by the use of
centralised Air Handling Units.
These direct or indirect drive, backward or forward curved
fan units are purposely designed and installed to
incorporate supply and return ducting and can be fitted with
various components such as mixing boxes, various types of
filtration, heater batteries, cooling coils and heat
recovery wheels.
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