[Bldg-sim] LEED modeling requirements for existing buildings

Michael Tillou michael.tillou at gmail.com
Thu Aug 21 13:41:26 PDT 2008


 I am inclined to agree with Amanda on this issue.   

Appendix G is a methodology for demonstrating energy performance beyond the
minimum requirements of ASHRAE 90.1.  If you alter a building envelope
element and want to claim energy savings beyond the minimum performance
requirements of ASHRAE 90.1-2004 then the baseline HAS to be ASHRAE
90.1-2004 minimum performance.  Otherwise you are no longer making a
comparison to ASHRAE 90.1-2004.  

LEED v2.2 EA-1 credits are based on a comparison to an ASHRAE 90.1-2004
baseline.  This fact should supersede the apparent contradiction in Appendix
G that is being discussed.  

Regards,

Mike

Michael Tillou, PE, LEED
Tillou Engineering, LLC
Williamstown, MA 01267
P: 413-458-9870 C: 413-652-1087



-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of James V. Dirkes
II P.E.
Sent: Thursday, August 21, 2008 1:53 PM
To: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] LEED modeling requirements for existing buildings

Dear All,

I was looking for something else and found this in a LEED-NC EAc1 update
document that I downloaded, but can no longer find on the USGBC site: 

"For existing buildings that are being renovated, the building envelope
design parameters for the Baseline Design should be modeled using the
existing (pre-retrofit) building envelope thermal parameters rather than the
ASHRAE Std. 90.1 prescriptive building envelope requirements for the
specified climate. Any proposed changes to the building envelope (such as
replacing windows or increasing roof insulation) should be modeled in the
Proposed Design."



The Building Performance Team
James V. Dirkes II, P.E., LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653
 

-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Jeff Ross-Bain
Sent: Thursday, August 21, 2008 12:29 PM
To: Amanda Bogner; Mark Sorensen; Carol Gardner
Cc: Eric O'Neill; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Spam:Re:LEEDmodelingrequirements
forexistingbuildings

My interpretation is different. Table G3.1 5(f) says for the building
envelope only: 

 "...the baseline building design shall reflect conditions PRIOR to any
revisions that are part of the scope of work being evaluated."

So, if I read this right, the baseline reflects the as-is conditions and the
design case reflects the new conditions. Now when there are additions, such
as adding an atrium or more space, then the baseline becomes 90.1 because
there was nothing there before.

Regards,

Jeffrey G. Ross-Bain, PE, LEED
Smith Dalia Architects
621 North Ave NE
Suite C-140
Atlanta, GA, 30308
404-892-2443
www.smithdalia.com 

P Build Green...Save Time

-----Original Message-----
From: Amanda Bogner [mailto:amanda at bvm-engineering.com]
Sent: Thursday, August 21, 2008 12:12 PM
To: 'Mark Sorensen'; 'Carol Gardner'; Jeff Ross-Bain
Cc: 'Eric O'Neill'; bldg-sim at lists.onebuilding.org
Subject: RE: [Bldg-sim] Spam:Re: LEEDmodelingrequirements
forexistingbuildings

The way I understand it is as follows:

1.  All parameters in basecase and as designed case = existing conditions if
not being altered.  
2.  If improvements will be made to component X in the as designed case, the
basecase component X = 90.1 requirements.

So, for example, if the envelope is not being altered, set it to existing
conditions in both the basecase and as designed models if the information is
available.  Otherwise, you can use 90.1 values in both models.  If the
glazing is going to be updated as part of the renovation, the basecase =
90.1 requirements, the as designed case = new glazing.  

A similar situation applies to system improvements.  For example, if a VFD
is going to be added to the cooling tower fan, the basecase will need to be
modeled as a two-speed fan per the requirements of 90.1, regardless of what
is existing.

Essentially, the existing building basecase becomes a moving target as
energy improvements are considered.  

If feel this is incorrect, please let me know.

Thanks,
Amanda Bogner
BVM Engineering, Inc.
404.806.2018 x103

-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Mark Sorensen
Sent: Thursday, August 21, 2008 10:57 AM
To: 'Carol Gardner'; 'Jeff Ross-Bain'
Cc: 'Eric O'Neill'; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Spam:Re: LEEDmodelingrequirements
forexistingbuildings

Table G3.1 item 5(f) indicates that you would use the U-factors and SHGC
from the existing building envelope prior to any revisions that are part of
the scope of work being evaluated. Someone please straighten me out on this
because I'm having a hard time understanding how it could be interpreted
that you need to use the minimum U-factors and SHGC from the tables in
Section 5 for the baseline building regardless of whether those envelope
components are being altered or not.

Regards,

Mark Sorensen CEM
Diversified Energy Services
5890 E. Pontaluna Rd.
Fruitport, MI 49415


-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Carol Gardner
Sent: Thursday, August 21, 2008 11:33 AM
To: Jeff Ross-Bain
Cc: Eric O'Neill; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Spam:Re: LEED modelingrequirements
forexistingbuildings

I thought that the rotation requirement was gone in any case.
Carol

Jeff Ross-Bain wrote:
>
> I asked the USGBC for an interpretation (not an official CIR) on the 
> need for rotating an existing building for modeling purposes and the 
> response was that the existing building does in fact need to be
rotated.
>
> This is their response (the "specified analysis" refers to building 
> rotation of an existing building):
>
> If the existing building being renovated is pursuing LEED-NC rather 
> than LEED-EB, then it would indeed be required to undergo the 
> specified analysis. This analysis is used to establish the baseline 
> for energy performance using the ASHRAE standard. LEED doesn't have 
> any specific exemptions for existing buildings in this requirement, 
> but if ASHRAE has some kind of exemption, we will honor that.
>
> Regards,
>
> */Jeffrey G. Ross-Bain, PE, LEED/*
> Smith Dalia Architects
> 621 North Ave NE
> Suite C-140
> Atlanta, GA, 30308
> 404-892-2443
> www.smithdalia.com <http://www.smithdalia.com>
>
> P Build Green...Save Time
>
>
------------------------------------------------------------------------
>
> *From:* bldg-sim-bounces at lists.onebuilding.org
> [mailto:bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Michael

> Tillou
> *Sent:* Thursday, August 21, 2008 9:15 AM
> *To:* 'Jay Keazer'
> *Cc:* 'Eric O'Neill'; bldg-sim at lists.onebuilding.org
> *Subject:* Re: [Bldg-sim] Spam:Re: LEED modeling requirements 
> forexistingbuildings
>
> Jay,
>
> 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 system types.
>
> regards,
>
> Mike
>
> 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 
> existingbuildings
>
> 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 altered*."
>
> 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?
>
> Thanks!
>
> */Jay Keazer, EI/*
>
> Energy Engineer
>
> TME, Inc.
>
> 2039 N Green Acres Road
>
> Fayetteville, AR 72703
>
> ph 479.521.8634
>
> fax 479.521.1014
>
> _jkeazer at tmecorp.com <mailto:email at tmecorp.com>___
>
> _www.tmecorp.com <http://www.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

> buildings
>
> Mark,
> 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!
>
> */Eric O'Neill/*
> Mechanical Engineer
> Energy Division - Michaels Engineering
>
> 811 Monitor St. Ste 100
> La Crosse, WI 54603
> v: 608-785-1900 x521
> f: 608-784-2270
> elo at michaelsengineering.com
> http://www.michaelsengineering.com
>
> *From:* Mark Sorensen [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 areas.
>
> Mark Sorensen
> Diversified Energy Services
> 5890 E. Pontaluna Rd.
> Fruitport, MI 49415
>
>
------------------------------------------------------------------------
>
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