Date: Wed, 29 Sep 2010 16:50:28 -0400
Reply-To: Bob Dritschel <dritschel**At_Symbol_Here**>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Bob Dritschel <dritschel**At_Symbol_Here**EARTHLINK.NET>
Subject: Re: Need fume hood/fire alarm help

Has the consultant considered the introduction of air into the room that does not come from other parts of the building, say from the outside via ductwork.
Bob Dritschel
----- Original Message -----
From: Kim Auletta
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Sent: Wednesday, September 29, 2010 1:42 PM
Subject: [DCHAS-L] Need fume hood/fire alarm help

We have recently renovated 2 floors of our 7 story Chemistry building. This job included adding MANY more fume hoods than were already in the building. The NFPA/ANSI/common sense code requires that the fume hoods stay & the supply air/HVAC system shuts off when the fire alarm is activated. Of course, this now makes the building so negative that they can't easily open the doors at the bottom of the stairwell/emergency exit and all the doors quickly slam shut. The consultant is at a loss of what to do to fix this.

How have your large buildings with numerous hoods dealt with this problem? Have you found a door mechanism that allows a person to overcome the severe negative imbalance and safely exit? Any advice or examples are greatly appreciated.

NFPA 45, Sect. 8.10.4 Fire detection and alarm systems shall not be interlocked to automatically shut down chemical fume hood exhaust fans.
8.10.5 Proper door operation for egress shall be maintained when the supply system shuts down and the lab exhaust system operates, creating a pressure differential.


Kim Auletta
Lab Safety Specialist
EH&S    Z=6200
Stony Brook University
EH&S Web site:

Remember to wash your hands!

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