[Bldg-sim] ASHRAE 62 question

Aleka Pappas APappas at enermodal.com
Thu Aug 26 15:17:18 PDT 2010


  When we provide energy design assistance for labs, a significant 
energy efficiency strategy is to try to get the client to really 
consider ventilation requirements and get them down as low as possible.  
This can be taken further with good focused ventilation strategies.
After going through this optimization process, though, I really think 
the final modeling has to have the same ventilation airflow rates in the 
baseline and proposed models (for occupied and unoccupied periods).  
Different types of labs will have different ventilation/ exhaust 
requirements; I don't see how 1 cfm/SF could be be applied to all 
laboratory spaces.
Having more resources to help design teams and clients reduce design 
ventilation rates as much as possible would be really useful....maybe 
there's a way to use 62.1 & Appendix G modeling to encourage this, but 
it would need to be a lot more detailed than 1 cfm/ SF.

*Aleka Pappas*
Building Energy Engineer

*ENERMODAL ENGINEERING, INC.
*/Inspiring energy and resource efficient buildings./*
**www.enermodal.com*
1325 E. 16th Ave.
Denver, CO 80218
APappas at enermodal.com
Office: 303.861.2070/ Direct: 720.221.1082


On 8/26/2010 2:20 PM, Paul Erickson wrote:
>
> Vikram,
>
> Good question...a bit interesting to try and answer.
>
> First, your calculations are correct.
>
> Second, it is interesting that only "educational science laboratories" 
> are mentioned, somehow suggesting that their use is different from 
> corporate and institutional labs.
>
> Third, EH&S often makes this determination and there is no agreement 
> among standards/guidelines dealing with lab ventilation so to impose 
> this bit of Std 62 seems like something that the USGBC should be 
> considering as it moves towards connecting Appendix G to Std 62 rates.
>
> Fourth, related to that last point, while Appendix G does not yet 
> directly require Std 62 rates for the baseline, LEED requires Std 62 
> rates for the proposed and 90.1 requires the baseline ventilation to 
> match the proposed.  So, it would seem that models should be 
> reflecting the 1 cfm/sf requirement.
>
> There is a grey area that I think may also be a point of discussion.  
> Minimum exhaust rates of various types are often only required when 
> the space is occupied.  As such, and considering that many university 
> EH&S folks are at least beginning to bat around the notion of, if not 
> adopt, a 4 ACH minimum during unoccupied periods, it seems fair to 
> have a value lower than 1 cfm/sf during unoccupied periods.  What's 
> your perspective on this?
>
> It'd be good if others chime in and help develop a consensus.
>
> Paul
>
> *Paul Erickson** *LEED® AP
> SR. Sustainable Design COnsultant
>
> 	
>
> 	
>
> *AEI* | AFFILIATED ENGINEERS, INC.
> 5802 Research Park Blvd. | Madison, WI  53719
>
> P: 608.236.1112 | F: 608.238.2614
> perickson at aeieng.com <mailto:perickson at aeieng.com>  | *www.aeieng.com* 
> <http://www.aeieng.com/>
>
> *From:* bldg-sim-bounces at lists.onebuilding.org 
> [mailto:bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Sami, 
> Vikram
> *Sent:* Tuesday, August 24, 2010 10:49 AM
> *To:* bldg-sim at lists.onebuilding.org
> *Subject:* [Bldg-sim] ASHRAE 62 question
>
> Just going through table 6.4 in ASHRAE 62.1-2007 it looks like the 
> minimum exhaust rates for labs (educational science laboratories) is 1 
> cfm/ft2. That amounts to an ACH of 6 (for a 10ft ceiling) and 6.7 for 
> a 9ft ceiling.
>
> Am I interpreting that correctly? Does that mean for LEED projects we 
> cannot go below 6 -- 7 ACH? Is there a way around it?
>
> *Vikram Sami*, LEED AP
>
> Sustainable Design Analyst
>
> 1382 Peachtree St. NE, Atlanta, GA 30309
>
> t: 404-443-7462    f: 404.892.5823     e: vikram.sami at perkinswill.com 
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