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Subject: [DCHAS-L] Prudent Practices Round Table - August 28th
Date: Thursday, August 13, 2020 at 5:00:05 PM
Author: James Kaufman <jim**At_Symbol_Here**LABSAFETY.ORG> 		Next by Date:
Subject: [DCHAS-L] Fall Meeting of the ACS Division of Chemical Health and Safety
Date: Thu, 13 Aug 2020 21:52:07 +0000
Author: Robin M. Izzo

From: Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**LISTS.PRINCETON.EDU>
Subject: Re: [DCHAS-L] Community Protection Strategies in the COVID Era Webinar
Date: Thu, 13 Aug 2020 21:01:00 +0000
Reply-To: Monona Rossol <actsnyc**At_Symbol_Here**cs.com>
Message-ID: 419403847.1386782.1597352460189**At_Symbol_Here**mail.yahoo.com
In-Reply-To <2F05490F-1862-487A-BAC4-F2BC323AB03F**At_Symbol_Here**keene.edu>


That point about UV is also made in the AIHA Aug 11 document: Reducing the Risk of COVID-19 using Engineering Controls.   I'm also pleased that it came out right after I had already presented my recommendations to the unions I work for that we require three data points from building engineers:
a) room exchanges/hour
b) MERV filter rating
c) Percent fresh air.

Now we can strike a balance with existing system.  See to AIHA paper to see how to do this.

EPA's website has a nice section on ionizers that will discourage their use better than I could.

My issue with the HEPA stand alone filters is that they create a circular pattern of air movement from the negative pressure at the front to the positive pressure at the back and so they filter primarily only near by.  The units usually come with the square feet they theoretically can clean, but it does not tell you the standard test for square feet assumes an 8 foot ceiling.  But in a small recording studio, they are heaven.

Monona


-----Original Message-----
From: Stuart, Ralph <Ralph.Stuart**At_Symbol_Here**KEENE.EDU>
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Sent: Thu, Aug 13, 2020 4:05 pm
Subject: Re: [DCHAS-L] Community Protection Strategies in the COVID Era Webinar

>  We normally talk about dilution ventilation and exhausted enclosures for protection from inhalation hazards.  In this situation, however, dilution might just more widely disperse viable virus particles.  You mentioned ionization, UV systems and HEPA filtration to control virus particles but all of those options might require significant time and investment.
> 
> >Other ideas?
> 
Just the familiar ones that Frankie and Robin talked about:
1. Control the source by wearing masks
2. Protect the target by providing distance from the source and limiting exposure times
3. Prevent cross contamination by disinfecting possibly infected surfaces.

These are all below engineering controls in the NIOSH hierarchy, but are manageable in the short and medium term. Redesigning buildings to accommodate the ventilation equipment needed to support the alternative technologies you mentioned is a long term process, particularly for buildings built in the 20th Century with decentralized ventilation systems.

Thanks for a good question.

- 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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