[Bldg-sim] G3.1.2.5 Clarification

[Bishop, Bill]

I think this idea that the baseline building design ventilation rate
should be equal to the minimum code required rate should be handled
cautiously by energy modelers. Implementing this requirement would
require modelers to do the following:
1.) determine which code(s) are applicable for the mechanical design
(local/state codes and ASHRAE Standard 62.1 for starters)
2.) calculate the minimum design ventilation rates for all zones, for
all applicable codes for the project, and determine the highest minimum
rates if the applicable codes differ
3.) compare the calculated rates to the ventilation rates in the
proposed design, for all zones
 
This is significant additional scope that is usually not required for an
energy model, including LEED models. This is the responsibility of the
mechanical designer. Unless I know that a project is pursuing LEED IEQc2
credit, or that a proposed mechanical design is using excessive
ventilation for some other reason, I will use the proposed design
ventilation rates in both the proposed and baseline models, which I have
been entering on a zone-by-zone basis to this point to meet my
interpretation of the G3.1.2.5 intent.
 
Regards,
Bill
 
William Bishop, PE, BEMP, LEED(r) AP | Pathfinder Engineers & Architects
LLP
Mechanical Engineer
 
134 South Fitzhugh Street
Rochester, NY 14608
T: (585) 325-6004 Ext. 114
F: (585) 325-6005
wbishop at pathfinder-ea.com
www.pathfinder-ea.com
P   Sustainability - the forest AND the trees. P
 
________________________________

This changes with the soon to be released 90.1-2010 which adds the
following;
 
If the minimum outdoor air intake flow in the proposed
design is provided in excess of the amount required by the
rating authority or building official then the baseline
building design shall be modeled to reflect the greater of
that required by the rating authority or building official
and will be less than the proposed design.
 
__________________________
 
Michael Rosenberg 
Senior Commercial Buildings Energy Analyst
ENERGY & ENVIRONMENT DIRECTORATE 
 
Pacific Northwest National Laboratory 
2032 Todd Street 
Eugene, OR 97405 
(541) 844-1960 
michael.rosenberg at pnl.gov <mailto:michael.rosenberg at pnl.gov>  
www.pnl.gov <http://www.pnl.gov> 
 
________________________________

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Demba
Ndiaye
Sent: Thursday, October 28, 2010 10:56 AM
To: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] G3.1.2.5 Clarification
 
Allow me to add my two cents...
 
My understanding and what my logic are telling me (whether they forgot
to clearly specify it in the Standard or not) is that OA design values
in the Baseline should never be:
 
1.       more than the design values in the Proposed; and
2.       more than the code-prescribed  values.
 
independently of DCV or this 30% over-ventilation.
 
______________
Demba NDIAYE
 
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Grammy
Sent: Thursday, October 28, 2010 10:36 AM
To: Julia Beabout
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] G3.1.2.5 Clarification
 
there are so many different opinions~
 
read the 90.1, and also 90.1 user manual and LEED requirement carefully~
On Thu, Oct 28, 2010 at 10:26 PM, Julia Beabout <juliabeabout at yahoo.com>
wrote:
yes!  Hear! Hear! 

My experience with submitted LEED projects has been.
1. proposed and baseline use the same OA quantity
2. you can take credit for DCV in the proposed building; however, the
baseline building is also required to use DCV in the spaces that are
required to have it as prescribed in 90.1
 
________________________________

From: Karen Walkerman <kwalkerman at gmail.com>
To: James Hansen <JHANSEN at ghtltd.com>

Cc: bldg-sim at lists.onebuilding.org
Sent: Thu, October 28, 2010 10:12:14 AM

Subject: Re: [Bldg-sim] G3.1.2.5 Clarification
 
The previous discussion also touched on the topic of requirements for
LEED models changing at the review stage (your reviewer indicating
something that is reflected NOWHERE in the documentation).  This really
makes me mad!  It requires extra time on our end because either:
 
1.  The reviewers are not properly educated as to the requirements
2.  The reviewers are making up requirements on their own
or,
3.  The reviewers are following guidelines provided to them by someone
(USGBC???) that has not been made available to the modeling
professionals who must abide by these rules.
 
--
Karen
 
On Thu, Oct 28, 2010 at 10:06 AM, James Hansen <JHANSEN at ghtltd.com>
wrote:
For what it's worth, regardless of what the various publications
actually say, the last 5-6 projects of mine have had reviewers that had
me confirm that when I use DCV in the proposed design, that the baseline
design MUST match the minimum ASHRAE 62.1-2004 (or 07) requirements.
 
So if you don't have DCV (shame on you!), then your baseline and
proposed models can have matching OA, and it can be whatever quantity
you want.
As soon as you incorporate DCV, the baseline model has to go down to
minimum 62.1 rates.  
 
GHT Limited
James Hansen, PE, LEED AP
Senior Associate
1010 N. Glebe Rd, Suite 200
Arlington, VA  22201-4749
703-338-5754 (Cell)
703-243-1200 (Office)
703-276-1376 (Fax)
www.ghtltd.com <http://www.ghtltd.com/> 
 
 
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Karen
Walkerman
Sent: Thursday, October 28, 2010 9:57 AM
To: Grammy

Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] G3.1.2.5 Clarification
 
There was a major discussion on this topic a few months ago, although it
may have been on the eQuest list-serve, I don't remember.  Try searching
the archives.
 
The general conclusion was that the current requirements are that the
baseline and proposed design models should have the same ventilation
rates, BUT that this doesn't make that much sense as you could
over-ventilate to the point where there is no added benefit to the
occupants, and major additional energy use.  The discussion was
primarily around LEED EA Credit 1, and there was some correspondence
between the simulation group and the LEED credit chair.  I believe that
they will be looking at modifying this requirement for LEED models in
the future.
 
--
Karen
 
On Thu, Oct 28, 2010 at 9:32 AM, Grammy <grammy.hkust at gmail.com> wrote:
In my opinion, the exception is means that keep the "design value" of OA
same in both proposed and basline, but use DCV only in proposed.
 
Because DCV can modify OA volume by the number of people in zone, and
the OA requirement is dynamics in simulation - which is too hard to keep
baseline same with, and also should not keep the same, if not where
does the saving come from?
 
On Thu, Oct 28, 2010 at 9:24 PM, Paul Riemer <Paul.Riemer at dunhameng.com>
wrote:
Section G.3.1.2.5 in 90.1-2007 has added an exception to the "shall be
the same" for models with demand controlled ventilation in the proposed
that is not required by Section 6.4.3.9. 
 
That alone is kind of confusing since it does not address what the
values should be when they are allowed to not be the same. 
 
I think they are trying to resolve the intersection of projects that use
more OA than Std 62.1 and utilize demand controlled ventilation.
The most recent Trane Engineers broadcast promised more changes coming
to this section (as addendum DA?) but I do not have anything published
to reference.
 
Paul Riemer
Dunham
 
 
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Kingsley,
Michael L.
Sent: Thursday, October 28, 2010 7:50 AM
To: Grammy; Jaigath Chandraprakash

Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] G3.1.2.5 Clarification
 
I agree.  Standard 61.1 sets the minimum acceptable ventilation rate.
The design ventilation rate can be higher, and the baseline rate should
be the same as the real design.
 
Best regards,
 
Mike
 
Michael L. Kingsley, PhD, PE, LEED AP | R. W. Beck, An SAIC Company
Senior Engineer/Project Manager
Energy, Environment & Infrastructure Solutions
office: 315.437.1869 x205 | mobile: 315.373.4081
 
________________________________

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Grammy
Sent: Thursday, October 28, 2010 8:38 AM
To: Jaigath Chandraprakash
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] G3.1.2.5 Clarification
 
In my opinion:
 
For LEED, the OA should increase 30% first. This is the propose
requirement.
 
Then for energy model, the baseline model should equal to proposed,
which means the baseline OA is also 30% more than 62.1 requirement.
 
On Thu, Oct 28, 2010 at 6:07 PM, Jaigath Chandraprakash
<cjaigath at yahoo.com> wrote:
Hello,
 
G3.1.2.5 states that minimum ventilation rates will be the same for
proposed building and baseline building. Does it mean that if my
building design OA rate is increased by 30%, my model will still be
based on the minimum OA required by 62.1 and is still equal to the
baseline building OA? Meaning my proposed building wont be penalized by
supplying more OA?
 
 
Thanks in advance.
 
 
Jaigath
 

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