Complete Guide to Ambient Fume Extraction

Ambient Air Filtration vs. Exhaust Ventilation

One of the first major choices to be made in choosing a solution for industrial dust and fume control is one between a filtration system and an exhaust system. A filtration system purifies the air, which can be recirculated into a facility, whereas a simple exhaust system just vents the air to the outside. Choosing between ambient air filtration and exhaust ventilation depends on the specific requirements of the workplace, the nature of the contaminants, and the desired level of air quality management.

Complete Guide to Ambient Air Filtration

Exhaust Ventilation

An exhaust ventilation system utilizes fans to pull air out of the facility, exhausting it to the outdoors. The rate of dirty air exhaustion and clean outside air being introduced to the facility will vary depending on the size of the facility and the contaminants within. Exhaust ventilation may be either localized (source capture) or general.
  • General exhaust ventilation (GEV) is a system designed to remove contaminated air from an entire area or building rather than capturing pollutants directly at their source. These systems reduce contaminant levels by the principle of dilution ventilation. The process involves introducing fresh air (makeup air) from outside into the facility, where it mixes with contaminated indoor air. This method can be effective in controlling odors, fumes and pollutants created by various production processes. Dilution ventilation lowers the concentration of contaminants, as constantly replacing contaminated air with clean outdoor air lowers the level of harmful substances, thus meeting indoor air quality goals and reducing contaminants below Permissible Exposure Limits (PELs). Makeup air is a crucial component of exhaust ventilation systems, ensuring that the air removed from a space is replaced with fresh, conditioned air. This balance is essential for maintaining indoor air quality, comfort, and building pressure.
  • Local exhaust ventilation (LEV) is a system designed to capture contaminants at their source before they can spread into the surrounding area. It uses hoods, ducts, and fans to directly remove pollutants from the air right where they are produced. This approach is particularly effective for tasks that generate hazardous substances, such as welding, chemical processing, or lab work. By targeting specific points, LEV systems prevent contaminants from entering the general air space, making them highly efficient in maintaining air quality. Additionally, LEV systems tend to be more energy-efficient since they focus on smaller, localized areas rather than treating the entire room or building.

Learn more:

Source Capture vs. Ambient Capture

Ambient Air Filtration

In an ambient dust collection system, instead of the air being exhausted to the outdoors, it is filtered of contaminants and recirculated inside the facility. While the exhaust ventilation system requires less infrastructure and maintenance (such as filter changes), opting for the filtration system offers numerous advantages, including significant energy cost savings. When heated or cooled air is exhausted outside, the fresh hot or cold makeup air will need to be heated or cooled depending on the season, which drives up costs. An ambient filtration system returns the conditioned air to the facility, thus lowering energy costs and reducing wear and tear on the HVAC system.

There are also environmental regulations to consider. In a facility where high volumes and/or concentrations of toxic fumes are produced, exhausting that untreated air to the outdoors could pose health risks and run the risk of violating environmental regulations set by the EPA.

Ambient Filtration vs. Exhaust Ventilation: Making the Right Choice

Ultimately, the choice between ambient air filtration and exhaust ventilation should align with your facility's specific operational needs, regulatory requirements, and economic considerations. Some factors to consider:
  • Nature of Contaminants: If contaminants are highly toxic, local exhaust ventilation (LEV) might be necessary as it captures pollutants at the source, preventing them from diffusing into the broader environment. For less hazardous contaminants, general exhaust ventilation (GEV) or ambient air filtration might suffice.
  • Energy Efficiency and Cost: Ambient air filtration systems recirculate filtered air back into the facility, which can be more energy-efficient and cost-effective, especially in climates where heating or cooling is expensive. Exhaust systems, while simpler, can significantly increase HVAC costs because they require constant replacement of expelled air with fresh, conditioned outdoor air.
  • Environmental Impact and Regulations: Exhausting untreated air outdoors may not always be feasible due to environmental regulations, especially if the contaminants are hazardous. Ambient filtration systems, which clean and recirculate the air, typically have less environmental impact and are less likely to violate such regulations.
Pros Cons
Ambient Air Filtration
  • Energy efficient as it recirculates filtered air, reducing HVAC costs.
  • Higher initial costs.
  • Higher maintenance due to regular filter replacements.
General Exhaust Ventilation
  • Better environmental compliance by not releasing contaminants outside.
  • Maintains consistent indoor air quality by continuously filtering air.
  • Simpler and often cheaper to install and maintain.
  • Increases HVAC costs as it requires conditioning of replacement outdoor air.
  • Potential environmental and health risks if venting hazardous substances outside.
  • May put companies out of compliance with environmental regulations.

Always consider consulting with an industrial air quality specialist to assess the specific needs and constraints of your facility to ensure compliance, safety and operational efficiency.

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