Stack Effect Impacts
Stack Effect in tall buildings is most often felt at the entrances.In cold climates it is felt as a flow of cold air into the building. In hot climates it is felt as cool air blowing out of the building: this is sometimes called reverse stack effect. Either way, stack effect represents an uncontrolled energy loss at best.
At its worst, it can cause:
-Irritating noise from whistling through doors and facade cracks;
-Infiltration of humidity and odor which can migrate through the building especially during HVAC system shutdowns;
-Increased difficulty opening and/or closing doors along with doors slamming if they are not controlled;
-Drafts and thermal discomfort from excessive heat gains, or losses, which can overwhelm the air conditioning systems;
-Adverse spread of smoke from a fire;
-Increased maintenance on elevator doors etc.; and
-These impacts can occur at all levels of the building.
-Upper level terraces exacerbate the problem.
Stack effect is a result of different air densities inside and out of a building that cause the pressure distribution of air in a building to be different from that outdoors. Often the combination of stack effect, wind pressures, and ventilation system operation combine to create complex pressure arrangements in buildings.
As the trend continues for increased building height, the need to control stack effect will continue. Passive strategies exist to manage stack effect.