[BLDG-SIM] App G 2004 question
Leonard Sciarra
leonard_sciarra at gensler.com
Wed Apr 18 07:05:19 PDT 2007
The baseline building is rotated to negate the effects of orientation,
ie, you get the benefit in your proposed design for GOOD site
orientation. One of the least expensive energy saving strategies is to
orient your building correctly, and if you have a good aspect ratio the
effects are even better.
Of course there are other issues that go into site selection, but for
those project teams that are looking at the design holistically, they
get the benefit.
I would put forth that many more than 10% of commercial buildings have
lots of site flexibility. Remember about 80% of commercial construction
is 3 stories or less and is being built in low density collar counties.
Leonard Sciarra, AIA, LEED ap
312.577.6580 (Dir)
G E N S L E R | Architecture & Design Worldwide
30 West Monroe Street
Chicago IL, 60603
312.456.0123
leonard_sciarra at gensler.com
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 <http://www.hargis.biz/>
________________________________
From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Charles
Christenson
Sent: Tuesday, April 17, 2007 3:47 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
==================
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
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
===========================
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/20070418/2a1cb38e/attachment-0002.htm>
More information about the Bldg-sim
mailing list