Remember though that NFPA 45 recommends you never let it go below 4 ACH even when unoccupied off hours.

And, to add to your comment, I remember saving a lot by simply training our security guards to close any open hood doors that they found during their tours after 7 PM. And record the hood location so the PI could get a gentle - and then not so gentle - reminder until it became a habit.

Richard Palluzi
PE, CSP,FAIChE

Pilot plant and laboratory consulting, safety, design, reviews, and training
www.linkedin.com/in/richardppalluzillc/

Richard P Palluzi LLC
72 Summit Drive
Basking Ridge, NJ 07920
rpalluzi**At_Symbol_Here**verizon.net
908-285-3782

-----Original Message-----
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Ralph Stuart
Sent: Tuesday, August 31, 2021 10:43 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Fume hood article of interest

> >Putting 58 fume hoods to sleep while unused results in substantial energy savings.

Sometime I long for my days in the labs when fume hoods had these things called "on/off switches"…

- Ralph

Ralph Stuart, CIH, CCHO
ralph**At_Symbol_Here**rstuartcih.org

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