[BLDG-SIM] App G 2004 question

Brandon Nichols BrandonN at Hargis.biz
Tue Apr 17 16:44:27 PDT 2007


Thanks Bill & Bing for your replies,
 
 
Previously I started this topic going again with a point-by-point
description of some implementation problems caused by the 'orientation
averaging' and 'fenestration leveling' requirements of LEED 2.2 /
90.1-2004 Appendix G; please refer to that post for further details.  
 
 
Here let me try to be as clear and concise as possible:
 
* There are, perhaps, only 10% of all buildings that can take advantage
of alternate orientations.  Most are site-constrained, or have already
been built.  
 
* There are perhaps a greater fraction than 10% of all buildings that
can take advantage of alternate glass distributions, however glass
distribution is also often constrained by site considerations.
 
* So to accommodate a minority of cases, LEED 2.2 / 90.1-2004 Appendix G
seems to impose a significant and relatively meaningless calculation
burden on the majority, by requiring the development of a fictitious
baseline that needs to be manually maintained outside of the simulation
software.
 
* How can we waive these requirements in LEED 2.2 for projects that
cannot realistically benefit from them, and substitute a "code minimum"
baseline oriented identically and glazed similarly to the proposed
building? 
 
 
On the last point, even if a site-constrained project could
'theoretically' benefit from orientation averaging or fenestration
leveling, in principle I believe LEED teams should have the option to
forgo that marginal benefit the sake of the simplicity, clarity,
accuracy, and meaningfulness of the comparative calculations.
 
 
 
Thanks for your time, and hard work on LEED...
 
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

 
 
 
 
 

  _____  

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of William
Bahnfleth
Sent: Tuesday, April 17, 2007 2:48 PM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] App G 2004 question


One of the perceived shortcomings of Ch. 11 as a method for computing
energy savings for green building rating purposes was that it did not
provide sufficient opportunity to take credit for energy savings through
envelope design and building orientation on the site.  The cited portion
of Ch. 11 (Table 11.3, item 5) requires all envelope components of the
Budget Building to be the same as the Proposed Building, eliminating
that opportunity.

The parallel part of Appendix G relaxes this constraint in a way that
should make it possible for the Proposed Building to show a greater
reduction in energy cost.  This is done by removing self-shading,
distributing fenestration uniformly instead of optimally, and by
averaging the effects of orientation.  If someone has done a robust test
of orientation averaging vs. best and worst case orientations that shows
negligible scatter around the mean, I am sure the ECB Subcommittee would
be interested to see it.  

The distribution of glazing was made uniform mainly because of the
intent to average multiple orientations.

Bill Bahnfleth

At 04:47 PM 4/17/2007, Charles Christenson wrote:


	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 <http://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
<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 <http://www.albertkahn.com/>  
	 
	
  _____  

	From: BLDG-SIM at gard.com [ mailto: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
<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
		
		
		
		 
		
		
		
		==================
		
		
		
		You received this e-mail because you are subscribed to
		the
		
		
		
		BLDG-SIM at GARD.COM mailing list.  To unsubscribe from
this
		mailing list
		
		
		
		send a blank message to
		BLDG-SIM-UNSUBSCRIBE at GARD.COM
		
		
		
	
____________________________________________________________
		
		
		
		Electronic mail messages entering and leaving Arup 
		business systems are
		
		
		
		scanned for acceptability of content and
		viruses
		
		
		
		 
		
		
		
		==================
		
		
		
		You received this e-mail because you are subscribed to
		the
		
		
		
		BLDG-SIM at GARD.COM mailing list.  To unsubscribe from
this
		mailing list
		
		
		
		send a blank message to
		BLDG-SIM-UNSUBSCRIBE at GARD.COM
		
		
		
		 
		
		
		
		 
		
		
		
		 
		
		
		
		 
		
		
		
		 
		
		
		
		You received this e-mail because you are
		subscribed
		
		
		
		to the BLDG-SIM at GARD.COM mailing list.  To
		unsubscribe
		
		
		
		from this mailing list send a blank message
		to
		
		
		
		BLDG-SIM-UNSUBSCRIBE at GARD.COM
		
		

	_________________________________________________
	
	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 <http://www.hargis.biz/> 
	 
	d | 206.436.0400  c | 206.228.8707
	o | 206.448.3376  f  | 206.448.4450
	 
	 
	
	
	 
	
	
	==================
	
	
	You received this e-mail because you are subscribed
	
	
	to the BLDG-SIM at GARD.COM mailing list.  To unsubscribe
	
	
	from this mailing list send a blank message to
	
	
	BLDG-SIM-UNSUBSCRIBE at GARD.COM
	
	This email message and any attachments are intended only for the
use of the addressee(s) named above.  This message may contain
privileged and confidential information, and may be protected by
copyright.  If you are not the intended recipient, any review,
dissemination, distribution or copying is strictly prohibited.  If you
received this email message in error, please immediately delete it and
notify the sender by replying to this email, or by telephone.  Thank
you.
	
	
	 
	
	
	 
	
	
	==================
	
	
	You received this e-mail because you are subscribed
	
	
	to the BLDG-SIM at GARD.COM mailing list.  To unsubscribe
	
	
	from this mailing list send a blank message to
	
	
	BLDG-SIM-UNSUBSCRIBE at GARD.COM
	
	
	 
	
	
	 
	
	
	==================
	
	
	You received this e-mail because you are subscribed
	
	
	to the BLDG-SIM at GARD.COM mailing list.  To unsubscribe
	
	
	from this mailing list send a blank message to
	
	
	BLDG-SIM-UNSUBSCRIBE at GARD.COM
	
	
	
	
	You received this e-mail because you are subscribed 
	to the BLDG-SIM at GARD.COM mailing list.  To unsubscribe 
	from this mailing list send a blank message to 
	BLDG-SIM-UNSUBSCRIBE at GARD.COM
	


_________________________________________________

William P. Bahnfleth, PhD, PE, FASHRAE
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/
_________________________________________________ 

==================
You received this e-mail because you are subscribed 
to the BLDG-SIM at GARD.COM mailing list.  To unsubscribe 
from this mailing list send a blank message to 
BLDG-SIM-UNSUBSCRIBE at GARD.COM


===========================
You received this e-mail because you are subscribed 
to the BLDG-SIM at GARD.COM mailing list.  To unsubscribe 
from this mailing list send a blank message to 
BLDG-SIM-UNSUBSCRIBE at GARD.COM
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20070417/794dba19/attachment-0002.htm>


More information about the Bldg-sim mailing list