Stack Effect in Tall & Supertall Buildings: Measurements from Real Buildings in Hot & Cold Climates

Duncan Phillips
Principal
RWDI, Guelph

Stack effect in tall buildings is caused by the combination of the building height and the air density difference caused by indoor - outdoor temperature differences. Stack effect can cause problems with elevator operability, doors whisling, unforeseen energy losses and an inability to open doors. At best these are nuisances, at worse they detract from the occupant experience and are causes of litigation in some jurisdictions. The problems experienced are a result of uncontrolled vertical flows in the elevator and stair shafts. Stack effect exists in both hot and cold climates and the strategies to deal with one do not necessarily work for the other.

While there is a fair amount of modelling conducted during building design to assess mitigation options, there is little real-world data available. The purpose of this seminar is to present real data collected from a number of (3) tall and super-tall buildings, in both hot and cold climates, and discuss the implications of the information in the data. The benefit of different mitigation strategies will be discussed as well as recommendations to improve the modelling conducted during design.

One key learning will be that the modelling conducted is typically too static and that the nuances of stack effect behaviour needs to include an understanding of how the different vertical shafts behave. In addition, overly simplistic design options intended to control stack effect are typically ineffective and this presentation will show why.