Hi, we have a mechanically ventilated building. In the review comments from our combined design and construction submittal we have received the following comment since the total square footage of the building those not correspond to the square footage of the rooms listed on LEED-online
“Note that all mechanically ventilated spaces must be included in the Ventilation Rate Procedure calculations, including spaces that have exhaust air.”
But our understanding is that only rooms with supply air should be listed on LEED-online?
Version 3 form.
How do we show compliance with the rooms that only have exhaust air?
Version 4 form.
Here my understanding is that we don’t have to comply with the requirement for every room, just in total, which means that a room with high air flows could compensate a room with low air flows, is that correct? But should not be ok for ASHRAE?
And/or should you include rooms with exhaust air in this table?
Thank you! /Veronika
Luis Miguel Diazgranados
Green Factory125 thumbs up
November 30, 2011 - 4:47 pm
We were planning to submit NET AREAS for the spaces to be submitted this credit. Do you think we should submit Gross areas for the spaces to be ventilated? This doesn't makes much sense, since walls don't need to be ventilated, but it looks like you had some trouble because the areas submitted for this credit didn't agree with the total square footage stated in PIf3. Any idea?
Jose Salinas
MrPoch & Associates
74 thumbs up
December 6, 2011 - 9:48 am
Hi Veronika,
did you get any clarification on how to list rooms that have exhaust air with version 4 form? Or if those rooms should actually be included?
Thanks!
Veronika Sundberg
Environmental Engineer - CertificationSkanska Sverige AB
120 thumbs up
December 6, 2011 - 10:28 am
Luis: I would exclude the walls and go with the NET area. If it is a big difference you could explain the reason. But it should not be a problem, it must be the same for all projects? I realized that our project probably had a lot of non ventilated rooms.
Jose: for v4 I have not submitted yet. But my understanding is to exclude them.
Nadia Ayala
Architect / LEED AP BD+CKILTIK Consultoría
52 thumbs up
July 11, 2012 - 4:26 pm
Hi Veronika,
Have you had any response regarding the inclusion or exclusion of the exhaust systems in the prerrequisite form?
Thanks.
Luis Miguel Diazgranados
Green Factory125 thumbs up
July 11, 2012 - 5:17 pm
Nadia, sometime ago I asked in the CS IEQp1 forum about exhaust systems and their inclusion in the forms. This is the link for the comment, and the answer I got. Hope it helps.
http://www.leeduser.com/credit/CS-2009/IEQp1#comment-19508
Nadia Ayala
Architect / LEED AP BD+CKILTIK Consultoría
52 thumbs up
July 11, 2012 - 5:28 pm
Luis Miguel,
Thank you for your reply. I had seen your post before, nevertheless, my case is somewhat different, since we are working in a large warehouse distribution facility. This building with an area of 160,000 sf, has 40 outdoor air intake louvers (1.22m x 1.22m each) and 8 exhaust fans with a capacity of 34,290 cfm each. There are no operable windows or any other kind of mechanical ventilation. We don't know how to document this for the prerrequisite and IEQ credit 2. Any ideas?
Luis Miguel Diazgranados
Green Factory125 thumbs up
July 11, 2012 - 6:29 pm
Well, I'm no expert in ventilation. Anyway, in your case I would try to argue that a total exhaust capacity of 274,320 cfm would generate an equal outdoor airflow rate through the intakes, if they are permanently opened, and their size is enough to allow for such a volume flow (I don't know if it would be, or how to calculate if it is). An airflow of this size would be a lot more than 30% above the required 9600 cfm for a 160,000 sq ft warehouse (without taking into account Ez and other variables). I would look out within ASHRAE manuals, handbooks, and other accepted bibiography to find support for my claims, and do the necessary calculations with the help of the ventilation designer. Finally I would check the Alternative Compliance or Special Circumstances box in the end of the credit form (not clear which one), and upload a narrative and calculations in support of my claims. After that I would hope for the best, hoping that my arguments are strong enough to be accepted by the reviewers.
As I say, I'm not an expert, and maybe I'm totally wrong, but this may give you an idea of what can be done to document your case. I hope you find a solution.
Nadia Ayala
Architect / LEED AP BD+CKILTIK Consultoría
52 thumbs up
July 11, 2012 - 6:46 pm
Thank you Luis Miguel. We will try to follow that approach if we can't find another way to document the case. I'll keep you posted.
Andrew Mitchell, P.E.
PrincipalMitchell Gulledge Engineering, Inc.
LEEDuser Expert
126 thumbs up
July 16, 2012 - 5:33 pm
Nadia, based on your comment above describing your system I think that you can fill out the template form using your exhaust fans. Look in ASHRAE 62.1 Table 6-2 at the bottom two entries. Depending on where the louvers are you will have to use a Zone Distribution Effectiveness of 0.8 or 0.5. Input the exhaust fans each as a separate system and assign the associated floor space to them. Your Ev will be 1 because each system 'serves a single zone'. That should give you enough information to fill out the form and hopefully achieve IEQp1 and IEQc2. Good luck.
Nadia Ayala
Architect / LEED AP BD+CKILTIK Consultoría
52 thumbs up
July 16, 2012 - 5:37 pm
Andrew, thank you for your insight. We'll go that way.