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Previous by Date: Subject: Re: [DCHAS-L] [EXTERNAL] [DCHAS-L] Atlantic Article on Ventilation Date: Monday, August 3, 2020 at 5:48:57 PM Author: Bruce Van Scoy <bvanscoy**At_Symbol_Here**TWC.COM> |
Next by Date: Subject: Re: [DCHAS-L] [EXTERNAL] [DCHAS-L] Atlantic Article on Ventilation Date: Tue, 4 Aug 2020 01:18:36 -0500 Author: yes |
Any UV light strong enough to inactivate a virus will have to be placed so as to completely avoid exposure to people. The additional problem is that contact time, even at those high exposures, needs to be 15 minutes or more. Given air movement, that kind of contact time is extremely unlikely in an occupied space and virtually impossible in a ventilation duct. The usual application for UV disinfection is in something like a biological safety cabinet, but only after hours, when no person is present.
Peter Zavon, CIH
Penfield, NY
PZAVON**At_Symbol_Here**Rochester.rr.com
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Bruce Van Scoy
Sent: Monday, August 3, 2020 5:49 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] [EXTERNAL] [DCHAS-L] Atlantic Article on Ventilation
Alicia,
Your right on with the problem, but I think we need to consider the increased impact of the reduction in outdoor air exchanges to increase energy efficiency over the last several decades. I have a location where employees are located every 6 ft. Although this meets the “recommended requirement” with what I know I would prefer either increased distances or a better method of room air disinfection. I wonder if anyone has looked at placing a UV light (I’ve forgotten the preferred wavelength, is it 865nm?) as a general room disinfection method? I am aware of the ACGIH TLV for UV, but I think this could be manageable.
Thoughts?
BruceV
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Frazier, Alicia S
Sent: Monday, August 3, 2020 3:11 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] [EXTERNAL] [DCHAS-L] Atlantic Article on Ventilation
Most people, including the CDC, have been making all their guidance on assumptions that primary transmission is from large droplet entrainment of particulate which has never made sense to me. And the fact that clusters been in cruise ships, meat packing plants and choir rooms where people are in close prolonged contact in poorly ventilated areas points to spread by aerosolization. While HEPA filters or filters with MERV ratings of 15 or greater with an increase of outside air intake is not an absolute cure all it certainly would be a good place to begin to reduce the concentration of active virus particulate in the air, then address distancing and maximum number of people in a room.
Alicia Frazier | 19100 Ridgewood Parkway | San Antonio, TX 78259
Direct: 210-626-6615 | Mobile: 210-412-3253
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Pam Auburn
Sent: Friday, July 31, 2020 3:30 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: [EXTERNAL] [DCHAS-L] Atlantic Article on Ventilation
I am certainly not an expert on this subject and have been thinking about it as we plan for a limited return to campus
This piece certainly did not "clear it up" but did placed some of the arguments in perspective
Pamela Auburn, PhD
2041 Branard
Houston TX 77098
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