Which location best describes the allowed termination point for exhaust fans?

Which location best describes the allowed termination point for exhaust fans?

• A. Inside the building
• B. In a shared duct with other equipment
• C. On the roof surface inside a sealed enclosure
• D. Outside the building

Answer: (B)

Exhaust air must have a controlled path to the outdoors that prevents re-entrainment into the building and keeps contaminants away from occupied spaces. The best termination point is into a shared duct with other equipment because this provides a defined, exterior discharge route through the building’s ventilation system. It allows proper dampers, backflow prevention, and coordination with the overall HVAC design, ensuring the exhaust does not recirculate indoors while still using an established outdoor exit path. Ending the exhaust inside the building would risk bringing pollutants back into occupied areas. Placing the discharge on the roof within a sealed enclosure can trap heat and fumes and complicate ventilation control. Terminating outside without a shared, properly designed duct could miss the necessary containment and balancing features that a coordinated exhaust system provides.

Exhaust air must have a controlled path to the outdoors that prevents re-entrainment into the building and keeps contaminants away from occupied spaces. The best termination point is into a shared duct with other equipment because this provides a defined, exterior discharge route through the building’s ventilation system. It allows proper dampers, backflow prevention, and coordination with the overall HVAC design, ensuring the exhaust does not recirculate indoors while still using an established outdoor exit path.

Ending the exhaust inside the building would risk bringing pollutants back into occupied areas. Placing the discharge on the roof within a sealed enclosure can trap heat and fumes and complicate ventilation control. Terminating outside without a shared, properly designed duct could miss the necessary containment and balancing features that a coordinated exhaust system provides.