[Bldg-sim] Easy Question

Wilson, Luke LWilson at integral-group.net
Wed Apr 14 08:12:26 PDT 2010


Good question. Appendix G says "40% of gross above-grade wall area" which leads me to believe that the 40% applies to the entire building WWR, not each exposure's WWR. Appendix G also says "shall be distributed on each face  of the building in the same proportions in the proposed design".

>From this I believe that the 40% WWR maximum applies to the entire building, while the proportion of the windows is the same for each exposure for both the proposed and the baseline.

Luke

From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Rodney Boerman
Sent: Wednesday, April 14, 2010 8:36 AM
To: Dana Troy
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Easy Question

Is maximum 40%WWR intended to apply to gross building or to principal exposures?  Assume 4 exposures: 1: 30% wall (100% window), 2: 20% wall (0% window), 3: 30% wall (0% window), 4: 20% wall (0% window).  Building WWR = 30%.  Would baseline window WWR match exposure 1 of design case at 100%WWR?  Prior to 2004 addendum #1, (equalized banding) would have modeled all baseline walls at 30%, but now will match proportions of design case, even if an exposure exceeds 40% - (and proportionally reduce all exposures only if building WWR exceeds 40%)?

On Tue, Apr 13, 2010 at 3:16 PM, Dana Troy <DTroy at glumac.com<mailto:DTroy at glumac.com>> wrote:
All,

As per Addendum A to 90.1-2004, you do NOT need to distribute the baseline glazing uniformly in horizontal bands across the four orientations. ASHRAE 90.1-2007 is basically 90.1-2004 incorporating the changes made in Addendum A. All addenda can be found here: http://www.ashrae.org/technology/page/132

If you read Table G3.1.5, it only states that the glass must not exceed 40% and must be distributed by the same proportions as the proposed building. Therefore, if you have a building with 50% WWR, you just have to reduce each window by 20%. This will still ensure that you have the same proportions (e.g. 20% of all of the glass on the north, 30% of all of the glass on the south, 40% of all of the glass on the east, and 10% of all of the glass on the west).

If your baseline WWR is less than 40%, then leave the window proportions, shapes, and sizes the same in the baseline and the proposed design.

This has all been well documented on the archives as well: http://lists.onebuilding.org/htdig.cgi/bldg-sim-onebuilding.org/2007-April/004077.html

Regards,

Dana Troy
Energy Analyst
LEED® Accredited Professional

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From: Carol Gardner [mailto:cmg750 at gmail.com<mailto:cmg750 at gmail.com>]
Sent: Tuesday, April 13, 2010 11:58 AM
To: Rimes, Christie
Cc: bldg-sim at lists.onebuilding.org<mailto:bldg-sim at lists.onebuilding.org>

Subject: Re: [Bldg-sim] Easy Question

Perhaps I'm missing something, but didn't he ask us how to calculate the window to wall ratio? If I'm not missing something, we need to know specifically, is the wall number wall only or wall + glass. This level of information is shown on the LV-D report in eQUEST, if he's using eQUEST. That's why I said, "it depends".

Carol
On Tue, Apr 13, 2010 at 11:45 AM, Rimes, Christie <Christie.Rimes at wspfk.com<mailto:Christie.Rimes at wspfk.com>> wrote:

For the 90.1-2004 I have always taken it as Luke explained, evenly distributed the WWR of the entire building.

However for 90.1-2007 I have interpreted the description to mean that the windows stay in the same location as the proposed building?


Error! Filename not specified.

From: bldg-sim-bounces at lists.onebuilding.org<mailto:bldg-sim-bounces at lists.onebuilding.org> [mailto:bldg-sim-bounces at lists.onebuilding.org<mailto:bldg-sim-bounces at lists.onebuilding.org>] On Behalf Of Vikram Sami
Sent: Tuesday, April 13, 2010 11:38 AM
To: JohannesHopf; bldg-sim at lists.onebuilding.org<mailto:bldg-sim at lists.onebuilding.org>; LukeWilson

Subject: Re: [Bldg-sim] Easy Question

Interesting point. I've never noticed this before, but this is different from 2004.

2004 stated :


Vertical fenestration areas for new buildings and additions shall equal that in the proposed design or 40% of gross abovegrade wall area, whichever is smaller, and shall be distributed uniformly in horizontal bands across the four orientations.


It looks like they have changed it (shall be distributed on each face of the building in the same proportions in the proposed design) to be more representative of the actualy building. I think 2007 is asking you to distibute it by orientation (if you have 40% on the west, 25% south, 20%north and 25% east in your design, you will have 40% on the west, 25% south, 20%north and 25% east in your baseline). This makes sense because otherwise we were doing the striping as well as the 4 rotations which was a little redndant.

(Not so easy question after all, but a good one).


--- On Tue, 4/13/10, Wilson, Luke <LWilson at integral-group.net<mailto:LWilson at integral-group.net>> wrote:

From: Wilson, Luke <LWilson at integral-group.net<mailto:LWilson at integral-group.net>>
Subject: Re: [Bldg-sim] Easy Question
To: "Hopf, Johannes" <johannes.hopf at dreso.com<mailto:johannes.hopf at dreso.com>>, "bldg-sim at lists.onebuilding.org<mailto:bldg-sim at lists.onebuilding.org>" <bldg-sim at lists.onebuilding.org<mailto:bldg-sim at lists.onebuilding.org>>
Date: Tuesday, April 13, 2010, 10:05 AM
ASHRAE 90.1-2007 Table G3.1 reads:
"Vertical fenestration areas for new buildings and additions shall equal that in the proposed design or 40% of gross above-grade wall area, whichever is smaller, and shall be distributed on each face of the building in the same proportions in the proposed design."

I wasn't aware that this requirement had changed in the 2007 version (thanks Cam!).

Luke

-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org<http://us.mc656.mail.yahoo.com/mc/compose?to=bldg-sim-bounces@lists.onebuilding.org> [mailto:bldg-sim-bounces at lists.onebuilding.org<http://us.mc656.mail.yahoo.com/mc/compose?to=bldg-sim-bounces@lists.onebuilding.org>] On Behalf Of Hopf, Johannes
Sent: Tuesday, April 13, 2010 12:55 PM
To: bldg-sim at lists.onebuilding.org<http://us.mc656.mail.yahoo.com/mc/compose?to=bldg-sim@lists.onebuilding.org>
Subject: Re: [Bldg-sim] Easy Question

I can't find this section in Table 1.3.? I just find the 40% limitation for
the baseline building. Can you post an excerpt?


Best regards


Johannes

-----Ursprüngliche Nachricht-----
Von: bldg-sim-bounces at lists.onebuilding.org<http://us.mc656.mail.yahoo.com/mc/compose?to=bldg-sim-bounces@lists.onebuilding.org>
[mailto:bldg-sim-bounces at lists.onebuilding.org<http://us.mc656.mail.yahoo.com/mc/compose?to=bldg-sim-bounces@lists.onebuilding.org>] Im Auftrag von Wilson, Luke
Gesendet: Dienstag, 13. April 2010 17:18
An: Eurek, John S NWO; bldg-sim at lists.onebuilding.org<http://us.mc656.mail.yahoo.com/mc/compose?to=bldg-sim@lists.onebuilding.org>
Betreff: Re: [Bldg-sim] Easy Question

John,

I'm assuming you are using ASHRAE 90.1-2007 Appendix G for your Baseline?
If so, the way I read it from Table G3.1 is that you should evenly distribute
the WWR of the entire building, not for each floor. Therefore I would use
11.4% for each floor.

Luke

-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org<http://us.mc656.mail.yahoo.com/mc/compose?to=bldg-sim-bounces@lists.onebuilding.org>
[mailto:bldg-sim-bounces at lists.onebuilding.org<http://us.mc656.mail.yahoo.com/mc/compose?to=bldg-sim-bounces@lists.onebuilding.org>] On Behalf Of Eurek, John S
NWO
Sent: Tuesday, April 13, 2010 10:22 AM
To: bldg-sim at lists.onebuilding.org<http://us.mc656.mail.yahoo.com/mc/compose?to=bldg-sim@lists.onebuilding.org>
Subject: [Bldg-sim] Easy Question

I have a two story building.  For the baseline I am evenly distributing the
fenestration.

The first floor window area is 462.2 ft^2
The second floor window area is 647.1 ft^2

The first floor wall area is 4858 ft^2
The second floor wall area is 4858 ft^2

In the base line model do I use:

First floor 9.5%
Second floor 13.3%

OR

First floor 11.4%
Second floor 11.4%
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