Industrial ventilation systems for enclosed buildings draw clean air in and vent old, contaminated air out to prevent pollutants from being breathed into the building’s occupants. They use a series of filters to remove odours, bacteria, dust, humidity and everyday pollutants.

Industrial ventiltion system design is a complicated process, and many factors can affect its performance. A well-designed and maintained industrial ventilation system helps protect employees from health risks, improves work quality, and increases high-quality industrial ventilation systems productivity. The goal is to keep employee morale high while maintaining safe working conditions and reducing the likelihood of accidents or other costly incidents.

In addition to the air movement that keeps stale, dirty air from entering clean air spaces, the system must also control temperature and humidity, and have adequate airflow rates. The system also needs to be able to handle the flow of materials being moved through the work area. The system may require a large amount of ductwork to deliver enough air volume to the work areas.

Often, the best way to understand how an industrial ventilation system works is through a computer simulation. ACGIH offers a Computational Fluid Dynamics (CFD) for Industrial Ventilation course that provides the foundations of CFD and the tools necessary to apply it to industrial ventilation problems. The course uses the Ansys software to conduct virtual simulations of different industrial ventilation systems.

An industrial ventilation system consists of an intake or recirculation fan that pulls in clean outdoor air, a hood that sits over the emission source, ductwork to transport the air and contaminant away from the hood, and an exhaust stack through which the contaminated air is discharged. The hood must be sized to allow airflow to reach the hood opening at a speed high enough to catch and transport contaminant particles until they enter the ducts. This speed is called the capture velocity.

A hood should be located as close to the emission source as possible, with minimal space between the hood and the worker. The hood should also be sized to provide sufficient clearance for material handling, machine operation, and maintenance. Air disturbances caused by abrasion, vibration, and other processes should be minimized or eliminated to help the system work as designed.

The hood’s capture velocity should be checked on a regular basis, as described in Appendix III:3-4. Symptoms that may indicate a problem include:

Workers complain of discomfort or health issues. Worker exposures are excessive although flow volumes and capture velocities are at design levels.

Ductwork that is too long or has too steep a slope reduces efficiency. Ducts that are not sized properly or installed correctly can have unacceptably low airflow velocity.

A duct system that relies on a mechanical draft can be expensive to operate because it requires a great deal of power to move air through the ducts. The system can also suffer from inefficiencies if the air is not heated or cooled properly. Regular and routine tests should be conducted to identify problems early, which can be corrected.