From: Ellen M. Sweet <ems325**At_Symbol_Here**cornell.edu>
Subject: Re: [DCHAS-L] Policy for Alarming Fume Hood
Date: Sat, 24 Feb 2018 15:18:55 +0000
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: BN6PR04MB0755F80660FBF2021C387BCD9AC30**At_Symbol_Here**BN6PR04MB0755.namprd04.prod.outlook.com
In-Reply-To <8893C617-4A92-4EB3-8D36-ADA0BB2DC372**At_Symbol_Here**keene.edu>


Hi Brandon,
I would suggest making the area of open to be full open instead of at 18" sash height. If this is occurring with a bunch of hoods and you are reaching exhaust capacity this may not be an option. You'd have to take those cfm's from someplace else. But, you'd have more assurance that the hoods are maintaining containment.
Another option might be to recalibrate the  monitors and also expand the range for alarming, say 40 fpm at the low end.

Ellen



From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU> on behalf of Stuart, Ralph <Ralph.Stuart**At_Symbol_Here**KEENE.EDU>
Sent: Saturday, February 24, 2018 7:26:38 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] Policy for Alarming Fume Hood
 
>the alarms are extremely uncomfortable for the labs and they end up muting them quite often.   Does anyone have thoughts or suggestions on this? 

This is a good question about an important issue. I recently saw somewhere the observation that
Data isn't information; 
Information isn't knowledge;
Knowledge isn't wisdom.
and the situation you describe points this out. In my mind, maintaining hood containment is in the "wisdom" realm rather than the "data" realm.

My experience is that ventilation engineers often treat hoods and hood alarms as regulatory devices for chemists' behaviors, rather than as tools for managing chemical vapors. If the lab scientists understand the containment properties of the hoods, then they should have the right to mute the alarms. Whether this ability is available depends on the design of the control system. An interesting challenge is that modern hoods are controlled by overall building EMS rather than on a hood by hood basis, whereas alarming is done hood by hood. This gives rise to much of the confusion you describe.

Fortunately, at Keene State, our lab building is small enough to have only one style of fume hood and the chemistry done in our teaching and research labs is small scale and consistent. So I believe that a rough idea of the containment properties of hoods allows our chemists and biologists to work in our hoods without relying on the hood alarms to indicate loss of containment. And as the building ages (it's about 12 years old now), the hood alarms are becoming increasingly unreliable in terms of maintaining calibration. So I am comfortable with them muting the alarms as they need to. This would be a much harder sell to me in a large campus research setting.

Good luck with this.

- 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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