[BLDG-SIM] App G 2004 question

Eric Yang Eric.Yang at smithgroup.com
Tue Apr 17 14:52:46 PDT 2007


To follow up this issue, I also have a question here: 

For existing buildings (e,g, tenant fit-out), is it necessary to rotate
the baseline building since the building is already built?   

 

Thanks.

 

Eric 

Smithgroup. 

 

________________________________

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Liu,
Bing
Sent: Tuesday, April 17, 2007 5:29 PM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] App G 2004 question

 

Charlie and Brandon,

The motivation and justification for rotating the baseline building in
Appendix G can be found in the 90.1-2004 User's Manual (example G-C
Fenestration). Here are two reasons why rotate the baseline building:

 

1. To give credit and reward if the proposed building is designed to
have the majority of windows facing either south or north. 

 

2. If the building is configured in such a way that it is capable of
shading itself (e.g. "L" or "U" shaped), this self shading is not
modeled in the baseline building.  

 

Thanks,

Bing 
                                                   
Bing Liu, PE, CEM, LEED AP 
Senior Research Engineer 
Pacific Northwest National Laboratory 
902 Battelle Blvd, MSIN:K5-16 
Richland, WA 99352 
Tel:  (509) 375-3710 
Fax: (509) 375-3614 

 

 

________________________________

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Charles
Christenson
Sent: Tuesday, April 17, 2007 1:47 PM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] App G 2004 question

As clarification, LEED v2.2 requires the use of the Performance Rating
Method from Appendix G, not the ECB method (which was used in previous
versions of LEED).  In fact, in the Reference Guide section of LEED v2.2
titled "Common mistakes made using the Performance Rating Method", the
first mistake listed is "The Energy Cost Budget Method (Section 11) is
incorrectly used rather than the Performance Rating Method (Appendix G)
to obtain EA Credit 1 credit". 

 

Brandon - when I first read Appendix G, I was puzzled by their
motivation.  Why rotate the building if you are already evenly
distributing glass?  I am still not sure what the justification from
ASHRAE is on that one.  I have not seen anything from USGBC that gives
any exceptions to the rotating requirement.

 

Charlie Christenson, LEED AP

Brummitt Energy Associates, Inc.

2171 India Street, Suite B

San Diego, CA  92101

tel: 619-531-1126

fax:  619-531-1101

cchristenson at brummitt.com

www.brummitt.com

 

A net-zero carbon company, using www.b-e-f.org/GreenTags

 

Brummitt Energy Associates, Inc. helps you achieve comfortable, highly
energy efficient, cost-effective projects by integrating the building
design with daylighting, electric lighting, and mechanical systems.
Consulting from early design through construction documentation, we
specialize in energy and daylight modeling, increasing financial
incentives, and documentation for Title 24, LEED(tm) and CHPS.  20 years
experience includes thousands of buildings, and more than 35 projects
pursuing and achieving LEED(tm) ratings, from Certified to Platinum.

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Leader,
Philip
Sent: Tuesday, April 17, 2007 1:02 PM
To: BLDG-SIM at gard.com
Cc: Shawn Gavras
Subject: [BLDG-SIM] App G 2004 question

 

The Appendix G is an informative appendix and is not part of Standard
90.1. It is merely informative and does not contain requirements
necessary for conformance to the Standard.

 

In the  Energy Cost Budget Method section in Table 11.3 under Section 5
Building Envelope, it describes the requirements for the Proposed
Building design and the Budget Building design.  The first paragraph
under the Budget Building design states.... The budget building shall
have identical conditioned floor area and identical exterior dimensions
and orientations as the proposed design, except as noted in (a), (b),
and (c) in this clause. 

 

There's nothing in the Standard stating you must rotate the building in
90 degree increments and average the results. We've never been asked to
do it to my knowledge by the USGBC during a LEED review of our projects.

 

Philip S. Leader, PE 
Director of Mechanical Engineering 
Albert Kahn Associates, Inc. 
7430 Second Ave. 
Detroit, Michigan 48202-2798 
Phone: 313-202-7834 
FAX: 3130202-7334 
Email: philip.leader at akahn.com 
Website: www.albertkahn.com 

 

________________________________

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Brandon
Nichols
Sent: Tuesday, April 17, 2007 3:12 PM
To: BLDG-SIM at gard.com
Cc: Shawn Gavras
Subject: [BLDG-SIM] App G 2004 question

All,

 

This is an old thread, but one I thought worth revisiting to see if
there have been any developments.  Specifically we are preparing a LEED
Silver project for submittal, and while we understand he intent of the
Appendix G 'multiple-orientation' and 'fenestration-leveling'
requirements, our evaluation is that they impose extensive calculation
requirements for arguably marginal returns on accuracy.

 

In the case of our specific building (as I would suspect the case of
90%+ of all buildings) there's simply no latitude to change the
orientation.  Similarly with glass distribution, the lobby and entryway
have the flexibility to be on one side and one side only of the
building, and thus distributing the glass equally amongst all facets for
the baseline model seems to add an unnecessary level of abstraction to
the comparative analyses.

 

Does imposing the requirement for analysts to spend considerable effort
developing fictitious baselines based on building orientations and glass
distributions that have 0% chance of construction seem to be a
reasonable requisite for LEED project certifications?  What I mean by
'considerable effort' is:

 

* That the all baseline numbers for each of the four orientations would
need to be extracted from the analysis software, averaged on a
spreadsheet, and a similar extraction done for all subsequent energy
efficiency measure (EEM) comparisons.  Posting these numbers from
analysis software to spreadsheets would be both time-consuming and
introduce another level of potential error, and thus require additional
error-checking.  

 

* That a new building would need to be developed, with glass
redistributed equally amongst all facets, for the four-point orientation
exercise described above.  Again, while this may sound reasonable from a
theoretical standpoint, practically speaking this requirement serves to
decouple the baseline from glazing-dependent energy efficiency measures.
How meaningful is changing the U-value or shading coefficient of the
glass in an EEM in comparison to a fictitious baseline, when the glass
distribution is crucial to determining whether or not the measure is
cost-effective?  As with building orientations, posting these numbers
from analysis software to spreadsheets would be both time-consuming and
additionally error-prone. 

 

All to fulfill the requirement of deriving a fictitious baseline for use
in the comparative analyses -- no doubt these requirements were
incorporated with good intention, but practical implementation
considerations seem to have not been considered carefully enough.

 

Further, we find the concept of comparing proposed energy efficiency
measures to a "code minimum" baseline building, oriented identically and
glazed similarly to each of the EEMs, to be intuitively more meaningful
to both the owner and project team (and thus presumably to the LEED
reviewer) than comparison to a fictitious baseline.  This approach
allows the baseline to reside in the analysis software, and EEM
comparisons accomplished using the built-in 'parametric run' features of
the analysis software (eQuest and others) to reduce the time-consuming
error-prone tediousness of extracting and posting numbers to a
spreadsheet for comparative evaluation.

 

Has anyone had success in obtaining LEED project approval when excepting
these 'building orientation averaging' and 'glazing-area leveling'
requirements?  What is required in terms of the LEED application to
waive these requirements?

 

Also, does anyone know if these requirements have been identified for
relaxation or revision in the next LEED update?

 

 

Regards

 

Brandon Nichols, PE
Mechanical
HARGIS ENGINEERS
600 Stewart St
Suite 1000
Seattle, WA 98101
d | 206.436.0400 c | 206.228.8707
o | 206.448.3376 f | 206.448.4450
www.hargis.biz

 

 

_________________________________________________

At 08:41 AM 1/24/2006, Bill Bahnfleth wrote:

 

Modeling the building in the specified orientations and averaging gives
an orientation-neutral baseline.

Appendix G has been developed with substantial input from experts at
PNNL and after discussions with USGBC. Glad to hear that modelers are
ignoring whatever they don't understand or find inconvenient.

Bill Bahnfleth
Member, ECB Subcommittee

At 09:42 PM 1/23/2006, Peter Alspach wrote:

	 A bit of a throw-back to the old 1989 version then?
	 
	-----Original Message-----
	From: Kevin Warren [mailto:kevin at warren-energy.com]
	Sent: Monday, January 23, 2006 5:46 PM
	To: peter.alspach at arup.com; bldg-sim at gard.com
	Subject: RE: [bldg-sim] App G 2004 question
	 
	Peter,
	 
	I believe the intent is to give you a way to get some savings
from
	orienting your building with an eye toward savings. If you pay
attention
	to the sun in your design (passive solar and/or daylighting),
you should
	get some savings relative to the average of the rotated
orientations.
	Similarly, you could get a penalty if you have too much
west-facing
	glass.
	 
	I'm not sure how strictly this provision is being enforced. Most
of the
	modelers I have spoken to ignore it, but that is a very
unscientific
	sample.
	These modelers may not be submitting to USGBC.
	 
	For a utility incentive program, it often does not make sense to
do this
	rotation. Those incentive programs typically care about the
savings from
	incremental changes to the design, particularly those changes
that carry
	an incremental cost. I'm not sure how one would determine an
incremental
	cost for your building's orientation, so it is not a factor that
would
	typically be eligible.
	 
	Kevin Warren, P.E., CEM, LEED AP
	Warren Energy Engineering, LLC
	(610) 255-3798 ph
	(610) 255-3406 f
	 
	-----Original Message-----
	From: bldg-sim at gard.com [mailto:bldg-sim at gard.com]On
<mailto:bldg-sim at gard.com%5DOn>  Behalf Of Peter
	Alspach
	Sent: Monday, January 23, 2006 8:04 PM
	To: bldg-sim at gard.com
	Subject: [bldg-sim] App G 2004 question
	 
	 
	Anyone out there know the source of why one would be required to
	simulate a building in an orientation that it is not in? This
doesn't
	really make any sense to me - am I missing something?
	 
	Peter
	 
	-----Original Message-----
	From: bldg-sim at gard.com [mailto:bldg-sim at gard.com] On Behalf Of
Rohini
	Brahme
	Sent: Monday, January 23, 2006 1:13 PM
	To: bldg-sim at gard.com
	Subject: [bldg-sim] App G 2004 question
	 
	I have a question about the Appendix G in 90.1, 2004.
	In Table G3.1 the baseline building is to be simulated as
follows:
	" Orientation. The baseline building performance shall be
generated by
	simulating the building with its actual orientation and again
after
	rotating the entire building 90, 180, 270 degrees, then
averaging the
	results. The building shall be modeled so that it does not shade
	itself."
	What does --- the building shall be modeled so that it does not
shade
	itself ---- mean?
	Does it mean that if there is, for example, an L shaped building
(which
	self shades), it has to be modeled as square? rectangle?
	Any thoughts on this appreciated.
	 
	Thanks
	- Rohini
	 
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_________________________________________________

William P. Bahnfleth, PhD, PE, Fellow ASHRAE

Professor of Architectural Engineering
Director, Indoor Environment Center

The Pennsylvania State University
104 Engineering Unit A
University Park, PA 16802 USA

voice: 814.863.2076 / fax: 814.863.4789
e-mail: wbahnfleth at psu.edu
www.arche.psu.edu/faculty/WBahnfleth/
http://www.engr.psu.edu/ae/iec/
_________________________________________________

 

Brandon Nichols, PE

Mechanical

HARGIS ENGINEERS

600 Stewart Street

Suite 1000

Seattle, WA 98101

www.hargis.biz

 

d | 206.436.0400  c | 206.228.8707

o | 206.448.3376  f  | 206.448.4450

 

 

 
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