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

[Pasha Korber-Gonzalez]

Maria & Cam---thanks for taking time to offer your guidance.

Maria--I was hoping to hear from your experience & advice.  :)
 Cam--thanks for confirming that I'm not blind!  :)

I don't have issue with the engineering theory of the topic--I understand,
agree and recognize thermal bridging effects and so forth (thanks to my
great engineering mentors in my younger days.)

What I was challenging specifically was that this was the first instance
that this Review Comment & request for Appendix A reference has been
presented on any of my LEED projects reviews---and I only am introduced to
it since the inception of the new Table 1.4 which specifically points out
the use of the Appendix A reference.

--(Thanks Shelia for your input also---I learned of the use of the new
Table 1.4 after I painfully filled it in for a project that was modeled
over a year ago.   In the future I will certainly be filling this table out
as I develop my LEED models as a simultaneous action from now on.   I like
how it is interactive and determines the correct references for us---agree
with the potential for less mistakes, but I dislike how it does take
significantly more time than the previous Table 1.4 which unfortunately
does eat into the project budget a bit more; however if we complete the
form during model development there may be potential to streamline/average
the additional work from the overall project time...)--

I've now read through Section 5.5.3 and the User's Manual info and have a
better understanding of the nature of the Review comment requirements.
I'm still baffled as to why this issue hadn't been brought up on any of my
previous project submissions as I had not changed my reporting approach
from then until now---I don't discount that it is an existing requirement
from prior to LEED 2009, but again it is frustrating when you think you are
applying 100% compliance to your document submissions and *out of the blue*
GBCI throws a new thing at us!

I respect that everything including LEED is a growing/improving process,
but it has been a painful growing process since the inception of GBCI
reviews.---(I just needed to vent.)    If GBCI is such an authoritative
review group then why didn't they have all this in place from the get go??
 I'm sure I'm not the only one who dislikes getting a curve ball---As a
LEED modeling veteran I thought that my submissions were closer to perfect
than not---it's the perfectionist-side of me that doesn't like to be
'blind-sided' by something that didn't seem to be a factor in the game
before now.

I guess today is already a productive day since I have learned something
New!    Thanks to all of you for sharing your time, experience & advice.
This list-serve is the BEST!!

Cheers,
Pasha




On Fri, Apr 12, 2013 at 8:33 AM, Maria Karpman <
maria.karpman at karpmanconsulting.net> wrote:

> Pasha,****
>
> ** **
>
> Appendix A is referenced by 90.1 Section 5.5.3. It is not a new rule, and
> must be used for determining thermal properties of the proposed designs
> because many simulation tools including eQUEST cannot capture
> two-dimensional heat transfer (thermal bridging) of the specified
> constructions. Thermal bridging is an especially big factor for steel-frame
> constructions, where calculating overall U-value of wall assembly using
> weighted average properties of frame and cavity sections (parallel path
> method) can distort result by factor of 2+ compared to the tables provided
> in Appendix A (such as Table A3.3 or A9.2B). Note that Thermal bridging is
> accounted for in Tables 5.5-x which list the baseline constructions. For
> example, for climate zone 5 (Table 5.5-5) minimum insulation R-value of
> steel-framed walls in non-residential spaces is R-13 cavity plus R-7.5
> continuous. If we do not account for thermal bridging, then the overall
> R-value of insulation in the cavity portion of the wall is R-20.5, and we’d
> expect that overall surface U-value (not accounting for gypsum board,
> siding, air, etc.) would be somewhere around 1/20.5=0.049 because cavity
> section is very wide compared to frame section. However the equivalent
> Assembly Maximum for the surface is U-0.064, which is what you‘d get if you
> use tables in Appendix A to calculate thermal properties of frame/cavity
> portion of the wall assembly instead of parallel path method. There is a
> nice discussion on that in 90.1 User Manual. ****
>
> ** **
>
> Good luck with your project,****
>
> ** **
>
> Maria****
>
> ** **
>
> *From:* equest-users-bounces at lists.onebuilding.org [
> mailto:equest-users-bounces at lists.onebuilding.org<equest-users-bounces at lists.onebuilding.org>]
> *On Behalf Of *PKConsulting
>
> *Sent:* Friday, April 12, 2013 8:55 AM
> *To:* Cam Fitzgerald
> *Cc:* eQUEST Users List
> *Subject:* Re: [Equest-users] LEED Review Comment for Appendix A
> constructions****
>
> ** **
>
> 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<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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