Ventilation is a mechanical system in an industrial building; the system is designed to bring fresh air into the building from outdoors and to expel contaminated indoor air outside.
In a typical workplace industrial roof exhaust fans are used to expel the contaminated air. The air will be contaminated from fumes, dust, vapors and the objective of ventilation is to provide a safe and healthy environment for those who work there. Although most industrial systems utilize fans and blowers, the simplest way to accomplish the task is to open the windows and doors.
Industrial systems are designed expressly to move a certain volume of air at a specific velocity, this results in the evacuation of the undesirable contaminates in the space. Although every ventilation system follows the same principles every installation is unique, matching the type of work and the amount of contaminates in the workplace.
The purpose of a ventilation system, whether residential or industrial is the same;
- Ensure a continuous supply of fresh, uncontaminated outside air
- Keep the temperature and humidity at comfortable levels
- Reduce the risk of fire or explosion
- Remove airborne contaminates
There are two types of ventilation systems; dilution and localized extraction. Dilution ventilation reduces the level of contamination by mixing fresh air with the contaminated air while on the other hand local ventilation captures the contaminated air at the source and exhausts it outside.
Features of dilution ventilation:
Dilution ventilation is nothing more than a technical tern for general ventilation. The objective is to supply and exhaust large volumes of air from the workplace using industrial roof mounted exhaust fans or fans placed in the walls of the building.
This type of ventilation controls the pollutants which are being generated by the various processes happening in the building by venting the entire space. This type of ventilation can be made more effective if the exhaust fan is located in close proximity to the source of the contaminates. Because of environmental concerns when dilution ventilation is used to control chemical pollutants the concentration cannot be high and the toxicity levels must be quite low.
Local exhaust ventilation:
This method is employed when it is important to trap the contaminates close to their source, this is in contrast to dilution ventilation which allows the contaminates to infiltrate the whole workplace before they are exhausted. This type of exhaust is executed by extracting the contaminates via a hood, through an air cleaner and eventually through industrial roof exhaust fans.
