CHAS readers many be interested in the link to the ASHRAE guidance on reopening schools and universities at
https://www.ashrae.org/technical-resources/reopening-of-schools-and-universities
It's a good review of basic concepts and best practices related to institutional ventilation systems, which many people are suddenly interested in.
The challenge I see in using this document is that the design basis for this document is to dilution of (chemical) pollutants to negligible levels. I'm not sure that dilution is a good approach for biohazards such as virus which can survive on surfaces for hours after it is introduced into a space. In the BSL-3 labs I have helped evaluate, direction of air flow was more important than number of air changes per hour.
- Ralph
Ralph Stuart, CIH, CCHO
Environmental Safety Manager
Keene State College
603 358-2859
ralph.stuart**At_Symbol_Here**keene.edu
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