Thread by @DavidElfstrom

1/ The Delta Fredericton has central corridor air pressurization and shared washroom exhaust. Lower floors may have inadequate pressure allowing air to flow out of suites. Failure of an exhaust fan can lead to direct connection between all suites on same shaft, @ShiftNB

https://twitter.com/ShiftNB/status/1395475894286827521

2/ This style of ventilation & exhaust is disproportionally prevalent in Ontario apartment building outbreaks. Before concluding fomite transmission a more detailed analysis by subject matter experts (building science) is required. @DFisman @IPACCanada docs.google.com/spreadsheets/d…

3/ More detail about the possible mechanisms from building science in this thread:

https://twitter.com/DavidElfstrom/status/1379814589395795975?s=20

4/ And this would also apply to the Magee House residence outbreak at University of New Brunswick which has been blamed on the elevator and other surfaces, without any mention of the functioning of the elevator cab exhaust.

5/ Hotel quarantine outbreaks in AU and NZ, initially blamed on surfaces, turned out to be airborne after detailed ventilation studies were conducted, including inter-zonal pressure differences and review of security camera footage.

6/ My calls to action are:
1⃣ Ensure any quarantine or isolation accommodation is tested beforehand to be compartmentalized (if multi-unit) or "air-gapped" (like trailers)

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2⃣ Ensure that anyone who has an active case of COVID-19 living in a multi-unit residential building or congregated setting, that is NOT compartmentalized or air gapped, should be moved to one that IS, until the infection is resolved.

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3⃣ For any outbreak, immediately bring in an independent engineer or building scientist to check for ventilation & filtration effectiveness.