Stack Effect in Tall Buildings ASHRAE NY April 2020 Chapter Meeting

Presented by Duncan Phillips with RWDI. Explains the science behind stack effect, common reasons for stack effect, and solutions to resolve the issue.
Presented at the ASHRAE NY April 2020 Chapter Meeting, the first chapter meeting in the coronavirus era
Stack effect exists in all buildings that are at a different temperature to that outdoors. Stack effect can be: a nuisance - e.g. whistling noises and/or cold drafts; offer operational challenges - e.g. keeping lobbies warm and/or elevator doors that do not close; or impose a danger to people - e.g. slamming doors and/or doors that cannot be opened.
Stack effect pressures on doors can exceed 0.8" H2O (200 Pa) and result in airflows through open doors that exceed 2000 fpm (10 m/s). Stack effect exists in buildings that are in both hot and cold climates although the impacts and resultant mitigation techniques are different for each type.
As buildings are getting taller, the strength of stack effect is becoming greater. By way of example, stack effect in some of the tallest buildings in the USA can approach 3.5” H2O. That is the pressure just created by indoor / outdoor temperature differences. Unfortunately, there are some misconceptions about how and why stack effect exists. This then leads to incorrect efforts to mitigate / fix. Further, the design community does not have a consistent design practice from jurisdiction to jurisdiction. The method of ventilating apartments in Toronto, NYC and Chicago can be different and each requires a different thought process to get right.
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[@drjny]

Is there anyway to fix this video so the audio synchronizes better with the video?

[@Ariccio123]

It's bad.

[@marcoguzzo7623]

Audio is approx. 12 mins and 30 secs ahead of video - use two screens and mute one to view in sync