From:
Dr Bob <drbob**At_Symbol_Here**FLOWSCIENCES.COM>
Subject:
Re: [DCHAS-L] Experience with Low Flow Fume Hoods
Date:
Sep 13, 2024 15:39 UTC
Reply-To:
ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
Message-ID:
<BN8PR07MB6340F32940CE6400508C9555D9652**At_Symbol_Here**BN8PR07MB6340.namprd07.prod.outlook.com>
In-Reply-To:
<YQXPR01MB4264ACB17E2A171351D1B684F3642**At_Symbol_Here**YQXPR01MB4264.CANPRD01.PROD.OUTLOOK.COM>
Hi Steve!
Lowering face velocity only becomes possible if
other factors support a safe lab situation under such conditions. Let me list examples of such factors. There too many to be comprehensive here..
-
Heat load of the equipment in the lab requires thermostatic control for workers and
experiments. If additional cool air is required in the lab for thermostatic control, a need to
exhaust the warmed air through some means might mean every CFM extra required for acceptable temperature is a CFM the hoods cannot save.
-
Number of hoods in the lab.
One or two hoods in a large lab may not be able to produce required lab air changes for contamination control evan at a much higher exhaust rate for the hoods.
-
The
nature of the “high-risk, highly variable academic research environments”.
Once the
possibility of saving money by lowering face velocity is affirmed, the risk must be defined along with the processes perceived likely to be present in the hoods themselves. Enemies of consistent use of low face velocity include frequent sash movements,
heavy traffic, opening and closing of lab doors, and older facilities with poor make-up air control.
Safe
containment is the reason fume hoods exist. Low volume fume hoods must not only be safe, but their function needs to be evaulated in the context of mechanical stability and room air quality as well.
Best regards,
Dr. Bob Haugen
Coordinator of Containment Research & Fume Hood Product Manager
Flow Sciences, Inc.
910 332 4878
www.flowsciences.com
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From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
On Behalf Of Stephen Beaton
Sent: Thursday, September 12, 2024 3:45 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: [DCHAS-L] Experience with Low Flow Fume Hoods
Hello everyone,
I recall there was some discussion a couple of years ago regarding low-flow fume hoods, and I’d like to revisit the topic. Specifically, I am interested in hearing about your experiences using low-flow fume hoods sized
with a maximum average face velocity of 60 FPM at an 18” sash opening in high-risk, highly variable academic research environments.
If you have insights or experiences—positive or negative—regarding their effectiveness, safety, or any challenges you’ve encountered, I would greatly appreciate your input.
Thank you in advance for your feedback!
Best regards,
Steve
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