[Bldg-sim] Does NFRC certification mean that window frame u-values are available for building simulation software inputs?

D. Charlie Curcija curcija at designbuildersoftware.com
Wed Jul 1 02:26:01 PDT 2009


Christina,

Simulation lab that performed simulations would have frame U-factors.  
NFRC staff would not be able to give you frame U-factors but could 
potentially direct you to the sim lab that modeled these windows.  
Alternatively, try to pry that info from Serious Windows. 

BTW, NFRC is finalizing new certification process, called Component 
Modeling Approach, where performance of framing, glazing and spacers is 
published separately, as well as whole product performance and 
EnergyPlus file for those that want to use info for building energy sim.

Charlie




-------- Original Message --------
Subject: Re: [Bldg-sim] Does NFRC certification mean that window frame   
 u-values are available for building simulation software inputs?
From: James V. Dirkes II, PE <jvd2pe at tds.net>
To: 'Christina A. Snyder' <CASnyder at ic.org>, bldg-sim at lists.onebuilding.org
Date: 6/30/2009 8:57 PM
> Dear Christina,
>
> Strictly (and somewhat jaded) opinion:  If you can't back up your technical
> claims, you probably aren't a company I would rely on to perform as
> advertised. Why bother with them at all if they can't support their claims?
>
>
> The Building Performance Team
> James V. Dirkes II, P.E., LEED AP
> 1631 Acacia Drive NW
> Grand Rapids, MI 49504
> 616 450 8653
>  
>
> -----Original Message-----
> From: bldg-sim-bounces at lists.onebuilding.org
> [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Christina A.
> Snyder
> Sent: Tuesday, June 30, 2009 8:34 PM
> To: bldg-sim at lists.onebuilding.org
> Subject: [Bldg-sim] Does NFRC certification mean that window frame u-values
> are available for building simulation software inputs?
>
> I've spent a month trying to pry window frame u-values from the customer
> support staff of Serious Windows, a company that claims to have NFRC
> certification on one of its window lines having a whole window R-value
> of 11. I've been trying to explain to the folks who are supposed to be
> able to get answers for me that building simulation software typically
> requires that you enter both center of glass u-values and window frame
> u-values so that the simulation software can approximate the whole
> window u-value for any size window you enter. They claim that the frame
> u-value info is not available and don't seem to be able to locate any
> data that is not posted on their website (only center of class u-value
> and a "whole window" u-value for an unspecified size of window).
>
> >From the NFRC website I get the following description of the
> certification process they claim to have gone through:
> "How does the NFRC Product Certification process work?
> First, a program participant submits product drawings and specifications
> to a simulation laboratory accredited by NFRC. The "sim labs" use
> approved computer software to determine energy performance ratings.
> Second, the participant randomly selects a product from its production
> line and sends it to an NFRC accredited testing laboratory for actual
> physical testing. If the ratings derived from the physical test are
> within the required tolerance of those derived from the computer
> simulation, the ratings are considered valid.
> Third, the sim labs and testing labs send their results to an NFRC
> accredited "IA" or Independent Certification and Inspection Agency for
> review.
> The IA confirms that the simulation and physical testing was done
> according to NFRC procedures. The IA inspects manufacturing facilities
> to make sure that the products submitted for testing are the same as
> those being produced.
> The IA will issue a certification authorization report (CAR) to the
> manufacturer after testing confirmation is completed and the participant
> has signed a license agreement with NFRC.
> Once the participant receives the CAR, the participant may place an NFRC
> label on the product. CARs are valid for four years from the physical
> test date; to maintain certification a participant shall recertify the
> product within the four-year cycle and not later than six months after
> certification expiration"
>
> >From this, it sounds like the NFRC must have calculated a frame u-value
> for a window they proposed to test (among other thermal performance
> figures), and then compared predicted performance to actual tested
> performance. Does anyone know if this is a reasonable assumption? Would
> their NFRC documentation & test results either state the frame U-values
> or allow one to calculate it? Would NFRC be able to provide me with the
> thermal performance properties I need even if the front line staff at
> this company is too incompetent to be able to figure out where to get
> this information?
>
> I realize that many of you are using simulation software that has a lot
> of window frames & glazing built into it so that you can just pick a
> product name from drop down menus, but many also allow inputting data
> for products not found in the built-in databases, and I think you need
> to be able to enter frame and glazing u-values separately then, don't
> you? I am designing one of the first certified Passive Houses in the
> United States, so I'm required to use the Passive House (PHPP) software
> for certification, and it lacks thermal data for most of the window
> products in the United States, since it was developed and used almost
> exclusively in Europe before this. But from what I remember from using
> Equest, Equest seemed calculate the thermal performance of glazing and
> frames separately, then prorate their contributions to whole window
> u-value based on the window dimensions. Also when you looked at its
> built-in product libraries it had both glazing and frame u-values, I
> think. So I don't think I'm asking these folks for anything special or
> difficult, do you? Accurate Dorwin and Thermotech companies have
> produced this info within days of the request.
>
> Do Serious Windows show up in any of your simulation software? if so,
> can you find them in the underlying window library databases and pass
> the frame u-values for the 925 and 1125 series windows, for fixed,
> awning, and casement windows? At least tell me if your window databases
> do list frame u-values for the options you can choose from your drop
> down menus, because I'm beginning to doubt my sanity. Or do you have any
> other suggestions as to where I can find frame u-values for these
> products if the company won't send it to me?
>
> Thanks for your input,
> Christina Snyder, architect and Certified Passive House Consultant
>
>   




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