Date: Thu, 30 Sep 2010 07:55:11 -0400
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: Kim Auletta <kauletta**At_Symbol_Here**NOTES.CC.SUNYSB.EDU>
Subject: Re: Need fume hood/fire alarm help
In-Reply-To: <20100929121615.834b022cd1aa24b0911e6cb2fed6c2a3.f9114e84f8.wbe**At_Symbol_Here**>
Thanks, everyone for your suggestions. I will pass them all on to the 
consultant & building staff.

Just to restate - the imbalance & inability to open the doors is not 
during our normal operations, but when the fire alarm is activated & the 
supply is shut down. We do have sufficient make up air in the building for 
our day-to-day work.

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

Remember to wash your hands!

09/29/2010 08:39 PM
Re: [DCHAS-L] Need fume hood/fire alarm help
Sent by:
DCHAS-L Discussion List 

Life safety has to trump the standards you mention.  I can speak directly 
to ANSI Z9.5 and that upcoming revision (which was written with an 
expectation that NFPA 45 is also addressing your situation in their next 
Z9.5 may not provide absolute clarity nor the answer that you're looking 
for but it does attempt to fix the unintended earlier recipe for egress 
issues.  And although the update/publication is being held up while we 
address a seprate public objection, the section addressing your question 
will read as follows: 
Within Section 5.2.3 Laboratory Ventilation - Emergency Modes
Left-hand column "shall" text
FIRE  Any manual or automatic means of detecting fire (such as a pull 
station or smoke detector) in a laboratory room shall also activate an 
appropriate fire emergency mode of operation for the room and/or building 
ventilation system.
The selected fire emergency mode shall operate all supply and exhaust 
equipment in the room in a manner that promotes egress, retards the spread 
of fire and smoke, and complies with applicable fire safety codes and 
Right-hand column "explanatory or should" text
The intent of the fire emergency ventilation mode is to promote safe 
egress.  This means apply negative pressurization in the room of fire 
origin in order to retard the spread of smoke and toxic fire gases to 
other parts of the facility but do not pressurize to the extent that the 
force needed to open the door is excessive. (Also refer to the current 
versions of NFPA 92A and NFPA 45.)
The common practice of cutting off supply air to a fire zone does not 
apply to some laboratories.  The combination of a high exhaust rate and no 
supply can depressurize a room so far that some occupants would be unable 
to open the doors.  The initial design of the laboratory ventilation 
system must include analysis of flow rates, pressure levels and forces on 
the door to ensure that egress is possible.

Steve Crooks, MS, CIH, CSP
Chair, AIHA/ANSI Z9.5-2xxxx
-------- Original Message --------
Subject: [DCHAS-L] Need fume hood/fire alarm help
From: Kim Auletta 
Date: Wed, September 29, 2010 1:42 pm
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU

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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