BIM Designs Ductwork…. Underground!
There are different methods for conditioning the air inside a building, the science of which is pretty interesting. Where do your eyes gaze when thinking about A/C cooling you down from summer’s heat? Chances are it’s not the floor.
The goal of most HVAC systems is to provide effective air distribution by combining outside air with return air circulating throughout the vents. Fans push air from the vents to generate the ideal temperature, humidity, and pressure. Duct work typically found above of a room, however some buildings, like churches or museums, boast floor-to-ceiling glass walls or architectural ceilings. St. Gertrude’s High School outside Richmond, Virginia has many of these unique features. Southern Air is responsible for the design/build of their mechanical, electrical and plumbing systems. So how do we condition the air in these rooms? One method is called displacement ventilation.
Displacement ventilation systems introduce air into rooms at low speeds using the natural buoyancy of warm air to remove contaminates for occupied breathing zones. The distribution of air to the low wall and floor is the main challenge with this type of system. Because floors lack the additional space ceilings provide, pressure mounts on designers to create an accurate building information model (BIM) during pre-construction phases.
Underground duct work for air distribution within a building is more common than you would think. It changes the order of construction by moving duct installation to the front, before the slab is poured. Once the underground duct is in place, pressure testing is conducted before closing out the ground plan and moving on.
The well-being of those inside a building remains the main focus of air distribution. The COVID-19 pandemic elevated the importance of occupant well-being over cost-efficiency of HVAC systems. Underground duct is proven to protect against corrosion, mold, mildew, radon, rust and air leaks. With its impressive ventilation effectiveness, ASHRAE recognizes displacement ventilation as a superb indoor air quality option.