From: Margaret Rakas <mrakas**At_Symbol_Here**SMITH.EDU>
Subject: Re: [DCHAS-L] ASHRAE guidance on Reopening Schools and Universities
Date: Tue, 7 Jul 2020 10:20:07 -0400
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
Message-ID: 2E51E11F-EF66-4454-B37E-6F87CBFB7019**At_Symbol_Here**smith.edu
In-Reply-To <2119826668.2976700.1594130856983**At_Symbol_Here**mail.yahoo.com>


Monona-can you pls cite the study on MERV-15?  I'm having trouble finding it-

Many thanks,
Margaret 

Sent from my iPhone

On Jul 7, 2020, at 10:10 AM, Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**lists.princeton.edu> wrote:

=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
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


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