=EF=BB=BF

All good advice except the MERV 13 filter recommendation.  A study now shows the bug goes through a properly installed MERV15.  So we are up to the full HEPA MERV 17 in our plans.  And that makes for a system upgrade in most facilities.  In a few cases, a shop with industrial dilution ventilation can be used -- which is even better..

We also, FYI, are finding that employers, if they really want to reopen, can find a way to test employees up to 3 times a week for COVID-19 (not antibodies, etc.)  And we now require level A personnel (those who can't distance or wear a mask due to the nature of their work) be tested three times a week.

Others get tested once a week.  And we are making it stick, Oh ye of little faith.  

Monona

-----Original Message-----
From: Stuart, Ralph <Ralph.Stuart**At_Symbol_Here**KEENE.EDU>
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Sent: Tue, Jul 7, 2020 8:28 am
Subject: [DCHAS-L] ASHRAE guidance on Reopening Schools and Universities

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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