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 kauletta**At_Symbol_Here**notes.cc.sunysb.edu 631-632-3032 EH&S Web site: http://www.stonybrook.edu/ehs/lab/ Remember to wash your hands! From: scrooks**At_Symbol_Here**PPEPPRO.COM To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU Date: 09/29/2010 08:39 PM Subject: Re: [DCHAS-L] Need fume hood/fire alarm help Sent by: DCHAS-L Discussion List
Kim, 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 revision.) 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 Ð 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 standards. 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. Regards, 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. Thanks! Kim Auletta Lab Safety Specialist EH&S Z=6200 Stony Brook University kauletta**At_Symbol_Here**notes.cc.sunysb.edu 631-632-3032 EH&S Web site: http://www.stonybrook.edu/ehs/lab/ Remember to wash your hands!
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