[BLDG-SIM] WWR definition

[Jon McHugh]

Rene, Larry and Gerald,
 
I think that the the underground wall area should be included for each floor that has windows.  These windows in partially below ground stories are providing light and views that are no less important than similar functions provided on upper floors.  However, if I have a skyscraper with 4 stories of underground garage of basement areas, I don't think these fully underground wall areas should be included.  Rene, in evaluating the energy and cost impacts of windows in buildings, it is important to look at the potential for daylighting or the value of view, otherwise an engineering analysis might conclude that we don't need any windows at all.
 
Perhaps this should be brought up with the 90.1 envelope committee.
 
Sincerely,
 
Jon McHugh, PE, LC
Technical Director
Heschong Mahone Group Inc.
11626 Fair Oaks Blvd #302
Fair Oaks, CA 95628 (Sacramento)
(916)962-7001 ext 38
(916)962-0101 FAX
e-mail: mchugh at h-m-g.com
URL: www.h-m-g.com 


________________________________

From: BLDG-SIM at GARD.COM [mailto:BLDG-SIM at GARD.COM] On Behalf Of Renee J. Azerbegi
Sent: Sunday, April 23, 2006 11:11 AM
To: BLDG-SIM at GARD.COM
Subject: [BLDG-SIM] WWR definition



It depends on the code in use. 

 

I submitted an official request (CM proposal) to the ASHRAE 90.1 Envelope committee to change the definition to only include the above grade walls but they declined it so it is still the above and below grade walls. The reason I sent the request is that architects tend to add more glazing to the above grade walls because they can include the below grade walls in the definition. I showed some modeling results of the difference between a two story building with one above and below grade wall in a few difference cities in the US and there was a significant energy impact.

 

However, I believe the IECC includes only the above grade walls. 

 

Renée

 

 

Renée Azerbegi, CEM, LEED-AP

President/Sustainable Design Engineer

ambient energy - solar & sustainable design solutions

t 303.278.1532 | f 303.278.8533 | c 303.885.2695

renee at ambient-e.com

ambient-e.com

________________________________

From: BLDG-SIM at GARD.COM [mailto:BLDG-SIM at GARD.COM] On Behalf Of Larry Degelman
Sent: Sunday, April 23, 2006 10:26 AM
To: BLDG-SIM at GARD.COM
Subject: [BLDG-SIM] 

 

Gerald et al,

 

The conventional definition of window-wall-ratio is the window area divided by the "gross" wall area, though the term "window-wall-ratio" is no longer among the Definitions section of 90.1-2004.  For that matter, WWR is not defined in the Abbreviations section.

 

Notwithstanding all that, the definition for "Gross Wall Area" is clearly defined in the 90.1-2004 User's Manual.

 

On page 5-30, example 5-G addresses "Determining Gross Wall Area", stating that this is very significant since the window area requirements are based on Window-Wall-Ratio (WWR).  

 

Answer (as shown on the same page):  "The gross wall area includes both above-grade walls and below-grade walls so that gross wall area is simply the perimeter of the building ... times the height..."

 

Larry D.

===================================== 

Larry O. Degelman, P.E.                  ldegelman at cox.net 

Prof. Emeritus of Architecture    Ph./Fax: 1-979-696-2506

Texas A&M University

=====================================

 

-----Original Message-----

From: BLDG-SIM at gard.com

To: BLDG-SIM at gard.com

Sent: Fri Apr 21 09:06:56 2006

Subject: [BLDG-SIM] ASHRAE 90.1 window-wall ratio

 

I recently came across a paper from "Building Energy

Codes Program" called "Setting the Standard" and lists

out various new code updates. It seems that currently

we are allowed to count below-grade walls as part of

the window-wall ratio calculations.  Does anyone have

an update on this or point me to the right resource to

confirm this information?

 

Thanks.

Gerald

 

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