Date: Wed, 21 Sep 2011 12:07:01 -0500
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: "Clark, Richard C" <rcclark**At_Symbol_Here**BEMIS.COM>
Subject: Re: Fume Hoods
In-Reply-To: <B06FE04AACB936438D57258499897CD91630D6DA6F**At_Symbol_Here**>

A concern that your lab designers will be bringing to the table is how the ducted hoods will upset the HVAC.   Certainly, planning HVAC for ductless hoods is much simpler (and cheaper).  However, the reasons given by others about the inadequacies of ductless hoods can't be minimized. 
The building airflow must not onl y accommodate the draw of the ducted hoods, but it also must compensate for the outside temperature (your climate).  I highly recommend a remote source of make-up air rather than a hood that su pplies its own make-up air from outside.  The inline heaters are never good enough to compensate for truly cold temperatures and incoming hot air will be most uncomfortable as well as ruining any temperature-controlled processes in the hoods.  Finally, the makeup air design should also compensate for door openings and closings .  Opening and closing a door shouldn't disrupt the hood face velocity .  Be alert to these issues and make sure they are part of the design; local HVAC engineers rarely design laboratori es and they will sweep these issues under the carpet.
Richard Clark
Sr. Research Chemist
Bemis Innovation Cente r
Neenah, WI 54956

From: DCHAS-L Discussion List [mail to:DCHAS-L**At_Symbol_Here**] On Behalf Of Michael Hojjatie
Sent: Wednesday, September 21, 2011 10:08 AM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: [DCHAS-L] Fume Hoods

Dear colleagues:

We are in the process of building a new La boratory and contemplating between using Dustless Fume Hoods vs. Ducted Exh aust Hoods. We will be using a variety of hazardous chemicals including carbon disulfide, acetonitrile, toluene, benzene, some carcinogenic suspect chemicals, hydrogen sulfide and sulfur d ioxide gases.

I appreciate sharing your experiences with ductless fume hoods and whether you recommend these type of hoods for haza rdous chemical work using the aforementioned chemical examples as well as advantages and disadvantages of these hoods v s. the ducted exhaust hoods (safety concerns, costs, maintenance, etc.)


Michael Hojjatie, Ph.D.< /p>

R&D director, TKI


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