[Equest-users] LEED Review Comment for Appendix A constructions

[Daniel Knapp]

I think he's referring to Table G3.1, No. 1.a for the Proposed model where it states that the simulation model of the proposed design shall be consistent with the design documents, including proper accounting of fenestration and opaque envelope types and areas.  

I can't speak to the inconsistency on GBCI reviews.  Was the U-value in this case particularly low?  As for the comment itself, I think it simply speaks to the need to include the effects of thermal bridging in determining the overall U-value for the assembly.  Maybe you've already done this, in which case I would suggest you simply document your approach in your response.  

I highly recommend checking out this paper published in 2011 which uses 3D heat flow modelling to calculate thermal transmittance through steel-framing, parapets, balconies, spandrels, etc.  

http://www.morrisonhershfield.com/ashrae1365research/Documents/MH_1365RP_Final_%20small.pdf

All the best,
Dan

—
Daniel Knapp, PhD, P Phys, LEED® AP O+M
danielk at arborus.ca

Arborus Consulting
Energy Strategies for the Built Environment
www.arborus.ca
76 Chamberlain Avenue 
Ottawa, ON, K1S 1V9 
Phone: (613) 234-7178 ext. 113
Fax: (613) 234-0740




On 2013-04-12, at 8:55 AM, PKConsulting <pasha.pkconsulting at gmail.com> wrote:

> Thanks Cam,   I couldn't find where it reads this in Table g3.1,   Could you give me a page reference please?   I need to provide my client with this reference info for their future projects.
> 
> Also can you explain why this hasn't been addressed on LEED projects in the past?   This is the first time I have received this comment on any of my LEED submissions.
> 
> Thanks,
> Pasha
> 
> Sent from my iPhone
> 
> On Apr 12, 2013, at 5:45 AM, "Cam Fitzgerald" <cam at energyopportunities.com> wrote:
> 
>> Good morning, Pasha,
>>  
>> Appendix G primarily provides very specific guidance for building the appropriate Baseline model to use as a benchmark to calculate the projected energy savings for your Proposed building as designed. Most of the guidance in Table G3.1 for the Proposed model indicates it must be modeled as designed. This is where appendix A comes in for the Proposed constructions. U-values  may only be calculated using the inverse of the sum of the R-values if each layer is continuous (e.g. uninterrupted by other materials such as steel studs or joists). Appendix A provides tables with the effective U-values for various common heterogeneous constructions. Depending on the construction, the overall U-value for the assembly can vary significantly from the U-value calculated by summing the U-value of the major components. The Appendix A assembly performance must be used for the Proposed constructions to accurately reflect performance of the building envelope. Hope this helps.
>>  
>> Have a great day!
>>  
>> Cam Fitzgerald
>>  
>> Energy Opportunities/a 7group company
>>  
>>  
>>  
>> From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Pasha Korber-Gonzalez
>> Sent: Thursday, April 11, 2013 6:00 PM
>> To: eQUEST Users List
>> Subject: [Equest-users] LEED Review Comment for Appendix A constructions
>>  
>> Hi --  hopefully others have run into this before.    We have a review comment that suggests that we need to revise our Proposed Construction performance values by reference of Appendix A constructions from 90.1 standard.
>>  
>> This is a new comment which I have not experienced LEED Reviewers addressing on past projects, and it seems to be in line with the release of the new Table 1.4 that is so interactive and also requires reference to Appendix A tables for proposed construction performance values.
>>  
>> I have re-read Appendix G and cannot find any required reference to using Appendix A performance values for proposed construction except for Fenestration that is Not NFRC rated.     Where does it state the requirement to use Appendix A values for all of the proposed envelope construction values??   Why is GBCI implementing this now, and it was never a factor before?
>>  
>> I need some education on this one please, I couldn't find any specific references on my own.
>>  
>> Thanks!
>>  
>> Pasha
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