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

James V. Dirkes II, PE jvd2pe at tds.net
Tue Jun 30 17:57:01 PDT 2009


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

-- 
  Christina A. Snyder
  casnyder at ic.org
  voice: 734-428-9249

_______________________________________________
Bldg-sim mailing list
http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org
To unsubscribe from this mailing list send  a blank message to
BLDG-SIM-UNSUBSCRIBE at ONEBUILDING.ORG




More information about the Bldg-sim mailing list