Supply air is defined as air delivered by ventilation to a space, which may include outdoor air, recirculated air, or transfer air. Which option best describes this concept?

• A. Air Exiting A Space To The Outdoors
• B. Air Delivered By Ventilation To A Space, Possibly Including Outdoor Air, Recirculated Air, Or Transfer Air
• C. Air That Is Only Outdoor Air
• D. Air That Is Only Heated Air

Answer: (B)

Supply air is the air the ventilation system introduces into a space to meet ventilation needs, and it may come from outdoor air, recirculated air, or air transferred from other spaces. That makes the option describing air delivered by ventilation to a space, possibly including outdoor air, recirculated air, or transfer air the best choice, because it captures all permissible sources of supply rather than restricting to outdoor air or to heated air alone. The other descriptions refer to air leaving the space (exhaust), or to concepts that don’t define supply air (air that’s only outdoor air, or only heated air).