[Equest-users] LEED Fenestration Modeling Question

[Robby Oylear]

Just as an aside, in Seattle we've been dealing with NFRC requirements for
at least the last six years.  Our local energy code requires NFRC
certification for all glazing products, otherwise you must use similar
default values to ASHRAE 90.1 Appendix A which obviously costs the project
money making up for the terrible default values.

The way to get proper NFRC values is to inform the architects about the
requirements for a LEED project and make sure the project specifications
require the curtainwall manufacturer to provide an NFRC certified product.
 This usually comes in the form of an NFRC Simulation Report which is a
preliminary simulation that is certified prior to installation on the site.

For more information on how the City of Seattle enforces these requirements
you can read the following:
http://www.seattle.gov/dpd/publications/cam/cam403.pdf

[image: Inline image 1]


On Tue, Apr 16, 2013 at 8:18 AM, James Hess <JHess at tmecorp.com> wrote:

>  FYI, another practical way to account for the effects of the framing is
> to use the charts provided by the curtain wall framing manufacturers.****
>
> ** **
>
> For example, here is the detailed catalog for the Kawneer system 1600 type
> 1:****
>
> ** **
>
>
> http://www.kawneer.com/kawneer/north_america/catalog/pdf/1600_Wall_Sys1__E--A.pdf
> ****
>
> ** **
>
> The charts and data (from pages 32) on allow us to estimate overall
> u-value and SHGC based on center of glass values and the ratio of Vision
> Area to Total Area (%).****
>
> ** **
>
> It’s fairly straightforward to document the Vision Area, but a very good
> rule of thumb is 90%.****
>
> ** **
>
> For example, if we had glass with a COG U-value of 0.28 and 90% Vision
> Area (i.e. 10% framing), the overall/System/Assembly U-value would be ~ 0.44
> ****
>
> ** **
>
> My experience is that this is completely acceptable for LEED/GBCI.  These
> charts were created by application engineers working for the framing
> companies, which I’m assuming they know this stuff way better than I do.
>  If you look at page 35, it says the U-factors, SHGC, and VT values are
> determined in accordance with NFRC 100 and 200.****
>
> ** **
>
> Other framing vendors, like EFCO, have similar charts that we can use.****
>
> ** **
>
> In my view, this is good enough to document assembly performance.  I would
> use the charts and move on.  If the new Table 1.4 includes space for a
> comment, I would reference the charts, and submit the charts if asked.****
>
> ** **
>
> There really is no other way to do this except try to calculate ourselves,
> which why bother when we have these charts.  If we ask the architects,
> often times, they will not understand what we are asking for.  They will
> probably only be familiar with the glass properties, not the combination of
> glass + framing.  The glass vendor will only give you performance data for
> the glass, not the combination of glass and framing.  I’m not sure why
> section 5.8.8.2 exists, except for packaged windows.  I haven’t found
> anybody that will give you a permanently installed nameplate or official
> certification for the entire fenestration system, at least for custom
> systems often encountered in commercial construction (i.e. curtain wall
> versus packaged windows).  Maybe the 5.8.8.2 requirement are met in other
> parts of country by somebody, but for now, I’ve found these charts from the
> curtain wall vendors to be very effective from a cost and time standpoint.
> ****
>
> ** **
>
> I would welcome any additional feedback on this.****
>
> ** **
>
> Hope this is helpful.****
>
> ** **
>
> Thanks!  J****
>
> ** **
>
> Regards,****
>
> * *
>
> *JAH*
>
> * *
>
> *James A. Hess, PE, CEM, BEMP*
> Energy Engineer
> TME, Inc.
> Little Rock, AR****
>
> Mobile: (501) 351-4667****
>
> ** **
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Paul Diglio
>
> *Sent:* Monday, April 15, 2013 2:34 PM
> *To:* Bishop, Bill; equest-users at lists.onebuilding.org
> *Subject:* Re: [Equest-users] LEED Fenestration Modeling Question****
>
>  ** **
>
> Thanks Bill, the comment you received is encouraging.****
>
>  ****
>
> Paul Diglio, CEM, CBCP****
>
> 87 Fairmont Avenue
> New Haven, CT 06513
> 203-415-0082****
>
> ** **
>
> www.pdigliollc.com****
>
> ** **
>
> ** **
>  ------------------------------
>
> *From:* "Bishop, Bill" <bbishop at pathfinder-ea.com>
> *To:* Paul Diglio <paul.diglio at sbcglobal.net>; "
> equest-users at lists.onebuilding.org" <equest-users at lists.onebuilding.org>
> *Sent:* Mon, April 15, 2013 2:45:18 PM
> *Subject:* RE: [Equest-users] LEED Fenestration Modeling Question****
>
> Paul,****
>
>  ****
>
> I recently received the following comment in a LEED review for a LEED-NC
> v2009 project:****
>
> ****
>
> This implies that Window v6.3 calculations are acceptable in lieu of NFRC
> ratings. The comment does not exclude the modeler from performing the
> calculation.****
>
> Of course, I have no idea if this is boilerplate language or if LEED
> reviewers have discretion here. It is also possible that requirements will
> become stricter for newer projects.****
>
>  ****
>
> Regards,****
>
> Bill****
>
>  ****
>
> *William Bishop, PE, BEMP, LEED AP **|** Pathfinder Engineers &
> Architects LLP*****
>
> Senior Energy Engineer****
>
>  ****
>
> 134 South Fitzhugh Street                 Rochester, NY 14608****
>
> T: (585) 325-6004 Ext. 114            F: (585) 325-6005****
>
> bbishop at pathfinder-ea.com <wbishop at pathfinder-ea.com>
> www.pathfinder-ea.com****
>
> P   Sustainability – the forest AND the trees. P   ****
>
>  ****
>
> *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 *Paul Diglio
> *Sent:* Monday, April 15, 2013 2:34 PM
> *To:* equest-users at lists.onebuilding.org
> *Subject:* [Equest-users] LEED Fenestration Modeling Question****
>
>  ****
>
> Folks:
>
> I am a bit confused when modeling unrated vertical fenestration for the
> proposed model.  90.1 states that we need to use the values determined in
> accordance with NFRC 100 or we can use the data in Table A8.2 for vertical
> fenestration per Exception b, Section 5.8.2.4.
>
> If so, the values in Table A8.2 exceed the maximum allowed fenestration
> u-values listed in Table 5.5-5 (my zone), so will this not disqualify the
> proposed building model?
>
> I have often found it impossible to get the architect to supply the NFRC
> assembly ratings of the glazing and field erected curtain-wall systems.
>
> I have used the LBNL Window 6.3 program to calculate the vertical
> fenestration ratings, but 90.1 Section 5.8.8.2 states that the fenestration
> product shall have a permanently installed nameplate or the manufacturer
> shall provide a signed and dated certification for the installed
> fenestration.
>
> I don't see any wiggle-room where 90.1 allows the modeler to calculate the
> NFRC rating of vertical fenestration.
>
> Saying that, I have submitted projects where I calculated the fenestration
> assembly u-values without any kick-back from the GBCI.
>
> I am concerned that the reviewers will push this issue since it is now
> clearly defined on the new Section 1.4 Table and if I submit my own ratings
> I will end up remodeling the project and/or the proposed building envelope
> will be rejected since it doesn't meet the mandatory requirements of
> Section 5.4.
>
> Any thoughts?
>
> Thank you,****
>
>  ****
>
> Paul Diglio, CEM, CBCP****
>
> 87 Fairmont Avenue
> New Haven, CT 06513
> 203-415-0082****
>
>  ****
>
> www.pdigliollc.com****
>
>  ****
>
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