[Equest-users] URGENT: Window U-values: Total window assembly v/s Glass only

Robby Oylear robbyoylear at gmail.com
Fri Jul 29 11:52:49 PDT 2011


Carol,

We definitely have the energy code on our side up here forcing projects to
provide NFRC data.  However, the way I interpret ASHRAE 90.1, the same
requirement exists.

ASHRAE 90.1 section 5.8.2.1 and 5.8.2.2 would indicate that U-factor, SHGC,
and air lekage rate are to be determined by a laboratory accredited by a
nationally recognized certification organization, such as the National
Fenestration Rating Council.  If no label is provided, a signed and dated
certification (simulation report) should be provided.

This tells me that a simulation in WINDOW by the energy consultant would not
be enough to verify glazing properties.

Am I reading this incorrectly?  Are you bypassing these requirements because
of the "*manufactured *fenestration" part?  ASHRAE 90.1 doesn't clearly
define the difference between site-built and manufactured.

-Robby

On Fri, Jul 29, 2011 at 11:41 AM, Carol Gardner <cmg750 at gmail.com> wrote:

> Robby,
>
> I would agree that NFRC values for the glazing alone would not be good
> enough. That is why I recommended using Window.
>
> I have not had the success you have had obtaining an NFRC rating for the
> window+frame because the buildings I have been working on are using
> site-built windows. In Washington, and Seattle in particular, you have had
> John Hogan working on your codes. It's entirely possible that the level of
> information you have available is greater than what I have seen.
>
> Carol
>
>
> On Fri, Jul 29, 2011 at 11:26 AM, Robby Oylear <robbyoylear at gmail.com>wrote:
>
>> Carol,
>>
>> I have to take exception to this:
>> "As far as NFRC, your Solarban glass data is NFRC rated which should be
>> good enough, I think. It's rare in commercial buildings to have a rating for
>> the entire window."
>>
>> From my first response:
>> In order to meet LEED EAp2 Minimum Energy Performance, the project must
>> comply with all mandatory provisions of ASHRAE 90.1-2007.  Section 5.4.2
>> Fenestration and Doors requires that fenestration performance be determined
>> per section 5.8.2.  Section 5.8.2.4 U-factor requires that the U-factor for
>> the overall fenestration area (including framing) be determined in
>> accordance with NFRC 100. If you do not have NFRC data available, values
>> from section A8.2 are the only acceptable alternative.
>>
>> NFRC values for the glazing alone not "good enough".  This is exactly what
>> the reviewer is trying to get at.
>>
>> I'd hardly call NFRC certification rare.  In the State of Washington NFRC
>> certification has been required for all glazing assemblies for over 10
>> years.
>>
>> How do you justify certifying that your projects have met the mandatory
>> provisions of ASHRAE 90.1 without NFRC data?
>>
>> *Robby Oylear, LEED**®** AP BD+C*
>>
>> *Mechanical Project Engineer*
>>
>> *Energy Analyst*
>>
>> * *
>>
>> *D* 206-788-4571 | *C* 206-354-2721
>>
>> *www.rushingco.com* <http://www.rushingco.com/>
>>
>> On Fri, Jul 29, 2011 at 11:12 AM, Carol Gardner <cmg750 at gmail.com> wrote:
>>
>>>
>>>
>>> On Thu, Jul 28, 2011 at 5:40 AM, Omar Katanani <omar at ecoconsulting.net>wrote:
>>>
>>>>  Dear all,
>>>>
>>>>
>>>>
>>>> Thank you for your responses.
>>>>
>>>>
>>>>
>>>>    1. Are the NFRC testing and the values in table A8.2 used for the
>>>>    Baseline, Proposed, or both scenarios?
>>>>
>>>> For the baseline windows, Appendix G gives the following instructions:
>>> Fenestration
>>> U-factors shall match the appropriate requirements in Tables 5.5-1
>>> through
>>> 5.5-8. Fenestration SHGC shall match the appropriate requirements in
>>> Tables
>>> 5.5-1 through 5.5-8.
>>> They are silent about frames but I would use one, match the frame width
>>> of your proposed window. Use an Aluminum frame with no thermal break.
>>>
>>>>
>>>>
>>>>
>>>>
>>>>    1. Let’s say I do not have NFRC test results and decide to use the
>>>>    values in table A8.2. For a clear double glazed and metal frame type, I get
>>>>    an assembly U-factor of 5.1. How can I input this into eQUEST? As far as I
>>>>    know, I can enter the glass properties and the frame properties. Do I have
>>>>    to play with the glass properties and check the LV-D report for the
>>>>    calculated Assembly u-value?
>>>>
>>>> A U of 5.1 does not make sense. Are you sure this isn't R?
>>>
>>>
>>>>
>>>>
>>>> Similarly, for the baseline, Tables 5.5-1 to 5.5-8 of ASHRAE 90.1
>>>> provide the assembly u-values for vertical glazing. How can I enter these
>>>> values into eQUEST?
>>>>
>>>>
>>>>
>>>>    1. I am attaching the specs of the proposed glazing. These numbers
>>>>    are for the glass only (note that the u-values reported are NFRC ones).
>>>>    Additionally, I know that the frame will be aluminium. Do I still need NFRC
>>>>    U-values for the whole assembly, or is the NFRC usually for the glass only?
>>>>    If yes, how can I calculate the whole assembly U-value (given that eQUEST
>>>>    doesn’t have the ability to calculate this)
>>>>
>>>>
>>> For your proposed building I highly recommend you use LBNL's Window
>>> program. In it you can select your window type, e.g. casement, picture,
>>> etc,, select your glass from their glass library, which is huge and
>>> definitely includes Solarban, and then model your frame using whatever
>>> information the architect gives you related to thermal breaks and spacers.
>>> After you run your window in the program you can select to save it to a DOE
>>> 2 report which will automatically go into your DOE 2 Window folder. Then you
>>> just have to select it from the pull down menu.
>>>
>>> Otherwise, input your glass values, as you are already, *and* input your
>>> frame data, the same data you got from your architect, and model it that
>>> way. When you look at your LV-D report you will likely see a variety of U
>>> values. That's because they will vary based on window size.due to the frame
>>> effect. You need to have a frame.
>>>
>>> As far as NFRC, your Solarban glass data is NFRC rated which should be
>>> good enough, I think. It's rare in commercial buildings to have a rating for
>>> the entire window.
>>>
>>> Carol
>>>
>>>>
>>>>
>>>>
>>>>
>>>> Thanks for clarifying this, as my project is outside the US and we are
>>>> not too familiar with standards such as NFRC.
>>>>
>>>>
>>>>
>>>> Best regards,
>>>>
>>>> Omar
>>>>
>>>> ___________________________
>>>>
>>>> Omar Katanani
>>>> Sustainable Design Engineer
>>>>
>>>> Email: omar at ecoconsulting.net
>>>>
>>>>
>>>>
>>>> EcoConsulting (Lebanon)
>>>>
>>>> Nahas Building, 4th floor
>>>>
>>>> 4 St-Maron Street / Georges Haddad Avenue
>>>>
>>>> Postal Code: 2028 5806 SAIFI
>>>>
>>>> Beirut, Lebanon
>>>>
>>>> Tel:          +961 (0) 1 971 266
>>>> Mobile:    +961 (0) 3 045 045
>>>>
>>>>
>>>>
>>>> EcoConsulting (UK) Ltd
>>>> 28 Marshalsea Road
>>>> London, SE1 1HF
>>>> Tel:  +44 (0) 207 939 0989
>>>> Fax:  +44 (0) 207 939 0981
>>>>
>>>> Website: www.ecoconsulting.net
>>>>
>>>>
>>>>
>>>>
>>>>   ------------------------------
>>>>
>>>> *From:* Robby Oylear [mailto:robbyoylear at gmail.com]
>>>> *Sent:* 28 July 2011 00:53
>>>> *To:* Omar Katanani
>>>> *Cc:* Brad Robinson; equest-users at lists.onebuilding.org
>>>>
>>>> *Subject:* Re: [Equest-users] URGENT: Window U-values: Total window
>>>> assembly v/s Glass only
>>>>
>>>>
>>>>
>>>> Omar,
>>>>
>>>>
>>>>
>>>> To directly answer your question:
>>>>
>>>>
>>>>
>>>> "I’m assuming that, given that I entered the u-values for the glass
>>>> only, and then I entered information about the frame, then I need not worry
>>>> about any conversions in U-values, *since eQUEST has all the necessary
>>>> information to calculate the equivalent u-value of the whole pane + frame
>>>> assembly,*right?"
>>>>
>>>>
>>>>
>>>> No.  Your method will result in an assembly U-value based on your input
>>>> glass conductance and whatever default frame properties that the eQUEST
>>>> wizard will use.  I have never tried to let eQUEST determine an assembly
>>>> value, as NFRC values are required for LEED and code compliance studies.  I
>>>> would not be surprised if the values eQUEST is calculating (shown in LV-D
>>>> and LV-E reports like previously mentioned) are much different than what
>>>> you'll actually see in the test results.
>>>>
>>>>
>>>>
>>>> Again, NFRC values are a LEED requirement, so unless you're just doing
>>>> preliminary analysis for a client, you need to receive NFRC simulation
>>>> reports or certified product directory numbers in accordance with NFRC 100.
>>>>
>>>>
>>>>
>>>> *Robby Oylear, LEED® AP BD+C*
>>>>
>>>> *Mechanical Project Engineer*
>>>>
>>>> *Energy Analyst*
>>>>
>>>> * *
>>>>
>>>> *D* 206-788-4571 | *C* 206-354-2721
>>>>
>>>> *www.rushingco.com* <http://www.rushingco.com/>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Wed, Jul 27, 2011 at 2:44 PM, <omar at ecoconsulting.net> wrote:
>>>>
>>>> Dear Robby,
>>>>
>>>> Yes, I am modeling for LEED purposes.
>>>> I'll look into A8.2. But at least, is my method correct for the proposed
>>>> scenario?
>>>>
>>>> Brad: I think you need to enter the center of glass u-value in the
>>>> "Glass Type", and then enter the frame properties in the "Window"
>>>> properties...
>>>>
>>>> Best,
>>>> Omar
>>>>
>>>>
>>>>
>>>> Quoting Brad Robinson <brad.robinson at yahoo.com>:
>>>>
>>>>
>>>>
>>>> Is the u-value listed for a manufacturer and specific model on the NRCAN
>>>> website centre of glass or overall assembly?  Many windows are custom made
>>>> to suit so I am unclear if each individual custom window would need to be
>>>> tested.
>>>>
>>>>
>>>>
>>>> In eQuest, when entering the window, if the u-value represents the whole
>>>> window, including frame, do you need to enter a frame width, conductance etc
>>>> as well under the Window Frame section under Window Properties?  Thanks.
>>>>
>>>>
>>>> Brad Robinson
>>>>
>>>>
>>>>
>>>> ________________________________
>>>> From: Robby Oylear <robbyoylear at gmail.com>
>>>> To: Omar Katanani <omar at ecoconsulting.net>
>>>> Cc: equest-users at lists.onebuilding.org
>>>> Sent: Wednesday, July 27, 2011 12:32:08 PM
>>>> Subject: Re: [Equest-users] URGENT: Window U-values: Total window
>>>> assembly v/s Glass only
>>>>
>>>>
>>>> Omar,
>>>>
>>>> The answer depends on the purpose of your study.  If you're trying to
>>>> get results for a client on the impact of the glazing on their energy
>>>> performance, this may be adequate.  Make sure you've entered in the framing
>>>> information properly (metal vs. non-metal).
>>>>
>>>> I'd recommend opening up your simulation output results file (xxxx.SIM)
>>>> and going to the either the last page of the LV-D report or sort through
>>>> your LV-E report to see what value eQUEST has calculated.  Compare these
>>>> values to the ASHRAE Fundamentals results for overall assembly values
>>>> including frame to see how close you've come.  I would not blindly trust
>>>> that eQUEST will give you an appropriate overall assembly value based on
>>>> entering only the center of glass number.
>>>>
>>>> However, if this is for a LEED study, this is not adequate.  This an
>>>> excerpt from an e-mail I sent out recently regarding LEED and NFRC
>>>> requirements.
>>>>
>>>> In order to meet LEED EAp2 Minimum Energy Performance, the project must
>>>> comply with all mandatory provisions of ASHRAE 90.1-2007.  Section 5.4.2
>>>> Fenestration and Doors requires that fenestration performance be determined
>>>> per section 5.8.2.  Section 5.8.2.4 U-factor requires that the U-factor for
>>>> the overall fenestration area (including framing) be determined in
>>>> accordance with NFRC 100. If you do not have NFRC data available, values
>>>> from section A8.2 are the only acceptable alternative.
>>>>
>>>> Robby Oylear, LEED®AP BD+C
>>>> Mechanical Project Engineer
>>>> Energy Analyst
>>>>
>>>>
>>>> D206-788-4571 |C206-354-2721
>>>>
>>>>
>>>> www.rushingco.com
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Wed, Jul 27, 2011 at 8:14 AM, Omar Katanani <omar at ecoconsulting.net>
>>>> wrote:
>>>>
>>>> Dear all,
>>>>
>>>>
>>>> I have a small question regarding entering
>>>>
>>>> window properties to eQUEST:
>>>>
>>>>
>>>> I have read a lot of emails in the forum
>>>>
>>>> discussing NFRC testing, LBNL Window 5 import, and other topics that I
>>>> haven?t
>>>> paid attention to before.
>>>>
>>>>
>>>> The way I modelled my windows is the
>>>>
>>>> following:
>>>>
>>>>
>>>>        1. I have manufacturer?s specifications listing the glass
>>>> U-values, not the total assembly.
>>>>        2. In the ?Glass Types? (eQUEST Detailed Mode), I created glass
>>>> types, and entered the glass conductance, visible transmittance, SC, and
>>>> emissivity from the manufacturer?s details I have.
>>>>        3. When creating windows, I specify which glass type (from the
>>>> ones I created in step 2), in addition to the frame width and conductance.
>>>>
>>>>
>>>>
>>>> I?m assuming that, given that I
>>>>
>>>>  entered the u-values for the glass only, and then I entered
>>>> information about
>>>> the frame, then I need not worry about any conversions in U-values,
>>>> since
>>>> eQUEST has all the necessary information to calculate the equivalent
>>>> u-value of
>>>> the whole pane + frame assembly, right?
>>>>
>>>>
>>>> I appreciate your feedback / comments
>>>>
>>>> today if possible, as this has become really urgent!
>>>>
>>>>
>>>> Many thanks,
>>>> Omar
>>>> ___________________________
>>>> Omar Katanani
>>>> Sustainable Design Engineer
>>>> Email: omar at ecoconsulting.net
>>>>
>>>> EcoConsulting (Lebanon)
>>>>
>>>> NahasBuilding, 4th floor
>>>>
>>>>
>>>> 4 St-Maron Street/ Georges Haddad Avenue
>>>> Postal Code: 2028 5806
>>>>
>>>>  SAIFI
>>>>
>>>> Beirut, Lebanon
>>>> Tel:          +961 (0) 1 971 266 <%2B961%20%280%29%201%20971%20266>
>>>> Mobile:    +961 (0) 3 045 045
>>>>
>>>> EcoConsulting (UK) Ltd
>>>> 28 Marshalsea Road
>>>> London, SE1 1HF
>>>> Tel:  +44 (0) 207 939 0989
>>>> Fax:  +44 (0) 207 939 0981
>>>> Website: www.ecoconsulting.net
>>>>
>>>>
>>>>
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>>>>
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>>>>
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>>>>
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>>>>
>>>
>>>
>>> --
>>> Carol Gardner PE
>>>
>>
>>
>
>
> --
> Carol Gardner PE
>
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