[Equest-users] Building area method ASHRAE 90.1

Cam Fitzgerald cam at energyopportunities.com
Wed May 23 06:07:42 PDT 2012


I have been following this thread and other than weighting in to say that
either method is acceptable, but the same methodology should be used for
both the Baseline and Proposed models (see Table G3.1#6 lighting for the
Baseline case).

 

Oscar,

 

With respect to your original question.If you have a mixed use building (say
a warehouse with an office area) and both building types are listed in Table
9.5.1, the LPD for each building type listed should be applied to the
associated area in the Baseline case. Assuming you told the reviewer you had
used the Building area Method in both models, you may want to see if this is
the focus of your comment.

 

Good luck,

 

Cam Fitzgerald

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Patrick J.
O'Leary, Jr.
Sent: Tuesday, May 22, 2012 7:28 PM
To: Nick Caton
Cc: eQuest Users; Oscar B.
Subject: Re: [Equest-users] Building area method ASHRAE 90.1

 

actually nick, i agree with you.  since i don't design lighting systems i
always ask the lighting designer which method they're using before i start
building a model.  almost all of the lighting designer's i've worked with
use the whole building area method, though as you point out the
space-by-space method can actually do a bit better for energy savings.

my point is that there isn't a mandate to use either the space-by-space or
whole building area method and there is no justification as far as 90.1-200x
is concerned for a usgbc reviewer to claim that the space-by-space method be
used.  the requirement per 90.1 is that the method be consistent in both the
proposed and baseline models.  space-by-space in both or whole building in
both.  this is what i've had to point out to reviewer's when i've received
comments.  just quote chapter & verse to show that the method
(space-by-space or whole building) used meets the 90.1 app g requirement and
is applied the same in both models.

as far as comcheck, comcheck reports from lighting designers are only as
good as the individual filling them out.  i've had lighting designers (with
all of their extra letters including pe after their names) fill them out
incorrectly.  i.e. not having all the lighting fixtures the same in drawing
schedules as input into comcheck, not having same number of fixtures in
drawings and in comcheck, not having the same floor areas in drawings and in
comcheck, and worst of all, not using the same methodology in comcheck that
they've used to design the lighting system in the first place.   yes, i've
seen comcheck reports that indicate space-by-space when the lighting
designer has told me whole building method.  and vice versa.  so i always
end up confirming my lighting take-offs (from the lighting plans) and
methodology with the lighting designer/electrical engineer and their
comcheck report.

On 5/22/12 3:58 PM, Nick Caton wrote: 

Hmm, I think I'm on the fence here.  


My practice is identical to Vikram's description for both energy modeling
and when documenting compliance for my lighting designs:  Choose whatever
method you wish, but always use the same approach for baseline and proposed.
This is pretty clear outside of Appendix G, when documenting compliance.
For modeling, I don't use either approach predominantly - it depends on the
project.

 

Since Patrick is pushing one side, I'll play devil's advocate =):  I can
affirm I've used "whole building" averaged LPD in proposed models for
successful LEED submission without incident multiple times, documenting that
clearly along the way, but I was using "whole building" for the baseline as
well in each instance.  I do not personally read 90.1 or LEED to explicitly
require LPD be defined with space-by-space for a proposed model.  Patrick, I
just checked each of your citations and the only specific call for either
method is when the lighting system has not been designed, in which case the
whole building approach is prescribed.  Keep in mind both methods should sum
to the same total installed watts for the proposed design.

 

Back to the neutral perspective:  I'll emphasis I do use both approaches.

 

To Oscar's case:  My general experience has been the whole building method
is less generous in net allowable watts when you run the numbers both ways.
In other words, you may stand to earn more LEED points by making your
baseline more detailed, using space by space.  My suggestion for Oscar is to
simply go with the reviewer's flow and possibly walk away with another point
tucked under your arm. it'll probably be a similar amount of effort on your
part relative to composing an opposing response, and you won't have to worry
about the reviewer disagreeing =).  

 

I agree space-by-space is 'better' for that reason alone - if different at
all, it tends to yield a better performance rating.  I will acknowledge
space-by-space is also "more accurate," notably so if you're simultaneously
defining distinct & accurate lighting schedules space-by-space, but whether
the corresponding additional time investment and resulting "accuracy boost"
are advantageous for a given LEED model is a toss-up.  I personally feel the
role accuracy plays in a LEED model is often overblown to a point of
silliness, but that's a personal call we each need to make and a whole
'nother discussion.

 

Hot related tip:  energy modelers and MEP designers alike need to be aware
of COMcheck.  I find it an invaluable time saver for speeding up takeoffs
for whole bldg & space by space calcs, and it's only as costly as eQuest.

 

~Nick

cid:489575314 at 22072009-0ABB

 

NICK CATON, P.E.

SENIOR ENGINEER

 

Smith & Boucher Engineers

25501 west valley parkway, suite 200

olathe, ks 66061

direct 913.344.0036

fax 913.345.0617

www.smithboucher.com 

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Patrick J.
O'Leary, Jr.
Sent: Tuesday, May 22, 2012 4:49 PM
To: Sami, Vikram
Cc: eQuest Users; Oscar B.
Subject: Re: [Equest-users] Building area method ASHRAE 90.1

 

as long as a lighting system has been designed:

according to ashrae/appendix g the uniform/whole building method applies a
uniform lpd to the BASELINE building only while the PROPOSED uses what is
designed - so long as the design is based on the whole building area method.
the lpd of the PROPOSED design should not be applied uniformly to the
PROPOSED building simulation.  

see appendix g, table g3.1, section 6 lighting, subsection b, page 173
(2004), page 179 (2007).  user's manual pages g-17/18 (2004 & 2007)

i would suggest to quote table g3.1 when replying to the reviewer's comment.
i have had reviewer's tell me i have to use the space-by-space method in a
simulation for both proposed and baseline buildings.  this is not correct.
what is correct is that the simulation reflect the methodology used by the
lighting designer.  if the lighting design is based on the whole building
method then the whole building method maximum lpd is used in the BASELINE
building.  if the design is based on the space-by-space method then the
space-by-space maximum lpd for each space type is used in the BASELINE
building.  in either case the PROPOSED building should reflect what is
designed.  by 'what is designed' i mean look at the lighting plans, lighting
schedules, and enter the lpd for each space/zone (thermal block) based on
the number of fixtures, watts per fixture, and square feet of space.



On 5/22/12 2:15 PM, Sami, Vikram wrote: 

The building area method applies a uniform LPD to the entire building. If
you do that in your baseline, you need to apply a uniform LPD to you
proposed building too. 

In general, I don't recommend using the building are method - the space by
space method is a better approach. 

 

 

Vikram Sami, LEED AP BD+C

Sustainable Design Analyst

1315 Peachtree St. NE, Atlanta, GA 30309

t: 404-443-7462    f: 404.892.5823       e: vikram.sami at perkinswill.com
<http://www.perkinswill.com/> www.perkinswill.com

Perkins+Will.  Ideas + buildings that honor the broader goals of society

 

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Oscar B.
Sent: Tuesday, May 22, 2012 4:38 PM
To: eQuest Users
Subject: [Equest-users] Building area method ASHRAE 90.1

 

 

 

How does the building area method work?

 

I just got a comment from the review team for a project pursuing LEED
certification.

 

I used the building area method for the baseline case and in the proposed
case I put the LPD from the lighting design. However they told me that the
same method has to be used in both cases.

 

Any help would be appreciate.







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