[Bldg-sim] Spam:Re: LEED modeling requirements for existingbuildings
michael.tillou at gmail.com
Thu Aug 21 06:15:17 PDT 2008
It is my understanding that that is the correct interpretation.
However, I don't think Eric's interpretation that the baseline rotation
requirement does not apply to existing buildings is correct. Let me explain
why I disagree.
Requirement f in Part 5 of Table 3.1 refers specifically to the baseline
building design (note the italics which signify that a phrase or word is
defined in Section 3 of the Standard) while Requirement a in Part 5 of Table
3.1 refers specifically to the baseline building performance (again in
italics). The baseline building design is not the same as the baseline
building performance and therefore Requirement f. cannot supercede
Requirement a in any case.
One last comment about the equal window distribution. ASHRAE 90.1-2004
Addendum a removes the equal distribution requirement for windows in the
baseline. If you're working on a LEED project I suggest you consider
adopting Addendum a to avoid this requirement. USGBC has allowed the use of
ASHRAE 90.1-2004 addenda. If you do decide to adopt Addendum a remember
that USGBC requires that you incorporate all the changes included in the
Addenddum. Addendum a has a total of eight changes to Appendix G, most
important of which are the changes to the calculation of the baseline HVAC
Michael Tillou, PE, LEED
Tillou Engineering, LLC
Williamstown, MA 01267
P: 413-458-9870 C: 413-652-1087
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Jay Keazer
Sent: Tuesday, August 19, 2008 10:42 AM
To: Eric O'Neill; Mark Sorensen; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Spam:Re: LEED modeling requirements for
What about the baseline envelope assemblies? As an example I have an
existing building where the windows are being replaced and insulation is
being sprayed on the outside of a built up roof.
In the same column of Table G3.1, requirement (b) states that "Opaque
assemblies used for alterations shall conform with 5.1.3" and requirement
(c) states that "The fenestration areas for envelope alterations shall
reflect the limitations on area, U-factor, and SHGC as described in 5.1.3."
5.1.3 states that "Alterations to the building envelope shall comply with
the requirements of Section 5 for insulation, air leakage, and fenestration
applicable to those specific portions of the building that are being
My interpretation is: because the windows and roof are being altered, I have
to use the appropriate U-factors and SHGC from the tables for the baseline
windows and roof. However, the walls are not being altered, so I can use
the existing construction for the baseline walls.
Does anybody have a different interpretation?
Jay Keazer, EI
2039 N Green Acres Road
Fayetteville, AR 72703
jkeazer <mailto:email at tmecorp.com> @tmecorp.com
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Eric O'Neill
Sent: Thursday, August 14, 2008 3:16 PM
To: Mark Sorensen; bldg-sim at lists.onebuilding.org
Subject: Spam:Re: [Bldg-sim] LEED modeling requirements for existing
Under ASHRAE 90.1 Appendix G, Table G3.1, Section 5, "Baseline Building
Performance" column, requirement (f) (take a breath.) it states that "For
existing building envelopes, the baseline building design shall reflect
existing conditions prior to any revisions that are part of the scope of
work being evaluated". So the rotation doesn't apply to you. Also, I
interpret that to mean the windows don't need to be redistributed either.
Hope that helps!
Energy Division - Michaels Engineering
811 Monitor St. Ste 100
La Crosse, WI 54603
v: 608-785-1900 x521
elo at michaelsengineering.com
From: Mark Sorensen [ <mailto:DEnergyServices at comcast.net>
mailto:DEnergyServices at comcast.net]
Sent: Thursday, August 14, 2008 10:40 AM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] LEED modeling requirements for existing buildings
When modeling an existing building, is required to calculate the proposed
building window to wall ratio and equally redistribute the glass area to the
baseline building and prepare models for the four rotation exposures? My
take is that for a proposed existing building, there is not an opportunity
to position the building to the most advantageous exposure and you could end
up being penalized if the baseline energy use is averaged for all rotations
but I have not been able to find any reference in LEED or ASHRAE to support
this. I'm not sure what to think about equal redistribution of the glass
Diversified Energy Services
5890 E. Pontaluna Rd.
Fruitport, MI 49415
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Bldg-sim