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Previous by Date: Subject: Re: laboratory/office environmental control questions Date: Mon, 8 Oct 2007 15:11:21 -0500 Author: Diane Amell |
Next by Date: Subject: Re: laboratory/office environmental control questions Date: Mon, 8 Oct 2007 16:41:09 -0700 Author: Jean & Ken Smith |
I would say that mixed use lab/office spaces is a very bad choice to make. The ventilation requirements for laboratories is generally a single pass with a 100% exhaust requirement. That would include hoods and snorkels as part of the ventilation system exhaust. The office system usually has a return air with a minimal exchange rate to conserve power. That exchange can be a low as 5% (not recommended) to as high as 10 - 20% to keep CO2, excess humidity, and office odors to minimum. I had a bad experience with a mixed system and it was a problem from the very first to get a proper air balance in the laboratories and the hallways that still has problems. Much of the tempered air that was required for the office was also exhausted from the lab in the single pass system due to the dual system. As you probably know, the offices are generally at a positive pressure to the outside to prevent untempered air inside, but the labs are generally at a negative pressure vs the hallway and outside to prevent any lab vapor escape into the non-work space or outside which complicates matters. If a clean room is involved, that room is at a positive pressure to all other spaces to prevent contamination inside. So you can see that it might lead to an untenable situation depending on the size of the facility. As far as the temperature and humidity situation, I don't believe that there is too much difference between the labs and offices unless a lab room demands a special situation. I believe that separate systems for the labs and the offices are by far the best way to go. Initially that cost may will be higher at installation, but future energy savings by having only the lab single pass exhaust and the office at the reduced exchange rate will save energy and, consequently, money. Kenneth Smith, CIH Calif. Dept. Health Chief EH&S, Retired Richmond Laboratory Facility -----Original Message----- From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**LIST.UVM.EDU] On Behalf Of al.muehlhausen**At_Symbol_Here**CIBAVISION.COM Sent: Monday, October 08, 2007 6:43 AM To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU Subject: [DCHAS-L] laboratory/office environmental control questions I have been challenged by my engineering group to consider the following questions as they pertain to a mixed use office/laboratory building. Any input would be useful. What is the target (set point) temperature, by space type. What is the acceptable range of temperature, by space type. What is the response time requirements of the temperature controlling system What is the target (set point) humidity, by space type. What is the acceptable range of humidity, by space type. What is the response time requirements of the humidity controlling system What is the minimum number of room air changes per hour, by space type. What is the maximum number of room air changes per hour, by space type. What are the pressure level requirements between / relative to each space type. What is the response time requirements of the pressure controlling system. Kind regards, Al Muehlhausen CIBA Vision Corporation Chemist/Certified Industrial Hygienist Health, Safety, and Environmental Officer JCE/JCA/BTI Office 678-415-4217 Cell 678-644-7026
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