I am remember my days in the Surgery Dept **At_Symbol_Here** Cleveland Clinic. This occurred back in the late 60s. When an OR was deemed finished for the day, the staff came in with masks, rubber outfits, and scrubbed all surfaces with what smelled like bleach. Floor, operating table, walls, ceiling, lights, whatever. Then they brought in the UV lamps - big suckers that took two to move. Same were aimed around the OR. Staff then left. Lamps were turned on. Presumably there were equally trained staff to shut them off and close down before the next day=E2=80™s surgery began.

Best. Kipp Barksdale

Sent from Mail for Windows 10

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

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

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  

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