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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>It’s all about the numbers.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>LEED Points, that is, not EUI.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Morgan Heater, P.E.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>BEMP, LEED AP<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>morgan@ecotope.com<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>206-322-3753 ext 209<o:p></o:p></span></p>
</div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
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<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";
color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:
"Tahoma","sans-serif";color:windowtext'> bldg-sim-bounces@lists.onebuilding.org
[mailto:bldg-sim-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Patrick J.
O'Leary, Jr.<br>
<b>Sent:</b> Monday, October 17, 2011 8:46 AM<br>
<b>To:</b> equest-users@lists.onebuilding.org; bldg-sim@lists.onebuilding.org<br>
<b>Subject:</b> [Bldg-sim] usgbc response to outdoor air question<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>back in september there was a thread about what the outdoor
air rate in a baseline simulation should be compared to a proposed simulation,
specifically when one is adding 30% more outdoor air to meet the ieqc2
requirement and earn 1 leed point. there were differences of opinions
about the flow rates between baseline and proposed being either the same (as
required in 90.1 app g) or the baseline being the calculated per 62.1 and the
proposed being as designed.<br>
<br>
so i submitted a support request to the usgbc and the reply i received is
below, but in short the response is that unless you're using dcv optionally the
outdoor air rates in the baseline and proposed energy simulations for eac1
should be the same. the response below gives the standard responses to
differing outdoor air rate scenarios.<br>
<br>
regards,<br>
patrick<o:p></o:p></p>
<p>[Fwd: Case 00531150: General LEED Questions<o:p></o:p></p>
<p>-------- Original Message --------<o:p></o:p></p>
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<p class=MsoNormal align=right style='text-align:right'><b>Subject: <o:p></o:p></b></p>
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<td style='padding:0in 0in 0in 0in'>
<p>Case 00531150: General LEED Questions [ ref:00D49UeD.5004GN692:ref ]<o:p></o:p></p>
</td>
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<p class=MsoNormal align=right style='text-align:right'><b>Date: <o:p></o:p></b></p>
</td>
<td style='padding:0in 0in 0in 0in'>
<p>Mon, 17 Oct 2011 06:54:51 +0000 (GMT)<o:p></o:p></p>
</td>
</tr>
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<td nowrap valign=top style='padding:0in 0in 0in 0in'>
<p class=MsoNormal align=right style='text-align:right'><b>From: <o:p></o:p></b></p>
</td>
<td style='padding:0in 0in 0in 0in'>
<p>"No reply GBCI" <a href="mailto:no-reply@gbci.org"><no-reply@gbci.org></a>
<a href="mailto:no-reply@gbci.org"><no-reply@gbci.org></a><o:p></o:p></p>
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<p class=MsoNormal align=right style='text-align:right'><b>To: <o:p></o:p></b></p>
</td>
<td style='padding:0in 0in 0in 0in'>
<p>patrick@<o:p></o:p></p>
</td>
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<p><o:p> </o:p></p>
<p class=MsoNormal>Dear Patrick,<br>
<br>
Thank you for contacting the Green Building Certification Institute. <br>
<br>
You ask very good questions related to the relationship between ASHRAE
Standards 62.1 and 90.1, and how these standards are applied across multiple
LEED Rating System prerequisites and credits.<br>
<br>
The simple answer to your question is that, for systems without demand
controlled ventilation, the outdoor air included in EA Credit 1 energy simulations
must be the same in the Baseline and Proposed cases. If the project is
attempting IEQ Credit 2 Increased Ventilation, then the values calculated in
IEQc2 must be used in the EAc1 Basline and Proposed case energy models. Note
that IEQc2 does not limit the project to providing only 30% more outdoor air
than AHRAE 62.1 Ventilation Rate Procedure minimums, so higher amounts are
acceptable, as long as they are modeled identically in both the Baseline and
Proposed case energy models.<br>
<br>
The following generic LEED Review Comment applies to ventilation systems that
do not have demand controlled ventilation:<br>
<br>
It is unclear whether the minimum outside air rates (in CFM) were modeled
identically in the Baseline and Proposed case for all zones not having Demand
Control Ventilation in the Proposed case. Please confirm that minimum outside
airflow (in units of cfm) was modeled identically in the Baseline and Proposed
cases using the proposed case rates. Additionally, please verify that all
systems in both the baseline and proposed case are modeled with zero outside
air flow when fans are cycled on to meet unoccupied setback temperatures unless
health or safety regulations mandate an alternate minimum flow during
unoccupied periods (in which case, the unoccupied outside air rates should be
modeled identically in the Baseline and Proposed case).<br>
<br>
The situation becomes a bit more complicated in you have systems that have
demand controlled ventilation (often implemented as Carbon Dioxide control of
outdoor air or as programmed control of outdoor air based on occupancy
sensors.) In this case the Baseline case energy model must include the minimum
outdoor air as determined by the ASHRAE 62.1 Ventilation Rate Procedure
calculations for all systems having demand controlled ventilation. <br>
<br>
The following generic LEED Review Comment applies to ventilation systems that
do have demand controlled ventilation:<br>
<br>
Demand control ventilation was modeled for credit in the proposed case.
Appendix G allows schedule changes for demand control ventilation as approved
by the rating authority (Table G3.1#4(Baseline)). As the LEED Certification
rating authority, GBCI requires that the outside air ventilation rates for the
Baseline case be modeled using minimum ASHRAE 62.1-2004 (or 2007 for LEED-NC 2009
projects) rates wherever credit is taken for demand control ventilation in the
Proposed case. The proposed case minimum rates at design conditions should be
modeled as designed. Please verify that the Baseline Case model reflects ASHRAE
62.1-2004 (or 2007) minimum rates for any spaces where credit is taken for
demand control ventilation, or revise the model accordingly. For all other
spaces, please confirm that minimum outside airflow (in units of cfm) was
modeled identically in the Baseline and Proposed cases. Additionally, please
verify that all systems in both the baseline and proposed cases are modeled
with zero outside air flow when fans are cycled on to meet unoccupied setback
temperatures unless health or safety regulations mandate an alternate minimum
flow during unoccupied periods (in which case, the unoccupied outside air rates
should be modeled identically in the Baseline and Proposed case).<br>
<br>
Finally, even though you don't address energy recovery in your question,
whether or not you have energy recovery in your ventilation systems may affect
how much better (or worse) your Proposed case energy models perform in relation
to your Baseline case energy models. <br>
<br>
The following generic LEED Review Comment addresses energy recovery in EAc1
energy models as it relates to ventilation systems.<br>
<br>
Energy recovery is modeled for credit in the Proposed case. Please provide
further information regarding the energy recovery efficiency, verify that
outside air is modeled with zero flow in both the Baseline and Proposed cases
during unoccupied periods when fans are cycled on to meet unoccupied setback
temperatures unless health or safety regulations mandate an alternate minimum
flow during unoccupied periods (in which case, the unoccupied outside air rates
should be modeled identically in the Baseline and Proposed Case), and indicate
the bypass mechanism used to bypass the energy recovery during mild conditions.
<br>
<br>
I hope that helps, but if you have any further questions or concerns, please
feel free to use the contact form at <a href="http://www.gbci.org/contactus">http://www.gbci.org/contactus</a>
and select "Follow up to GBCI Response," inputting your case number
from this email's subject line.<br>
<br>
Best Regards,<br>
<br>
Dan Katzenberger, P.E., CEM, BEMP, LEED-AP BD+C<br>
<br>
Green Building Certification Institute <br>
2101 L Street NW, Suite 500 <br>
Washington, DC 20037 <br>
800-795-1746 (phone)<br>
202 828-5110 (fax) <br>
<a href="http://www.gbci.org/contactus">www.gbci.org/contactus</a><br>
<br>
The text above represents a staff opinion of a particular issue, and does NOT
set any precedent to be upheld during a LEED Certification Review. For official
rulings in advance of a LEED Certification Review, customers should utilize the
Formal Inquiries process available in LEED Online that results in a Project
Credit Interpretation Ruling (Project CIR) and possibly a LEED Interpretation
(formerly CIRs or Public Rulings). Applications for LEED Certification will be
thoroughly reviewed based on USGBC Member balloted and approved LEED Rating
Systems, with addenda, and USGBC approved LEED Interpretations, or Project CIRs
administered by GBCI, as applicable. Please note that certain inquiries
submitted to USGBC are forwarded to GBCI for reply as appropriate.<br>
<br>
<br>
_______________________________<br>
CUSTOMER EMAIL ADDRESS: <br>
patirck@<br>
<br>
CUSTOMER INQUIRY:<br>
I am trying to verify what the minimum outdoor airflow rate required for EAc1
is and am not sure if this requires a CIR. <br>
<br>
If the Proposed outdoor air ventilation is a minimum of 30% higher than the
minimum required by ASHRAE 62 in order to achieve 1 LEED point for credit IEQC2
is the Baseline outdoor air rate also 30% higher than the minimum required by
ASHRAE 62? or would the Baseline outdoor air ventilation rate be the minimum
outdoor air rate per ASHRAE 62 calculations. <br>
<br>
In other words, if ASHRAE 62 requires a minimum of 1,000 CFM of outdoor air,
and 1,300 CFM is provided to attain 1 LEED point via IEQC1, is the Baseline
outdoor air flow rate 1,000 CFM or 1,300 CFM in the energy simulation? <br>
<br>
90.1-2007/2004 both say the minimu m outdoor airflow rates
shall be the same for both the proposed and baseline building designs, as does
the user manual. <br>
<br>
But this logic seems to reward the Proposed simulation by conditioning the
additional outdoor air supplied (300 cfm in the example above) to achieve IEQC1
in the Baseline system as well as the proposed. <br>
<br>
The logic of using the minimum required in the Baseline case is reflected in
EAC1 in the equipment efficiency requirements. Baseline efficiencies are the
minimum required, e.g. SEER 13 for packaged units. <br>
<br>
It is the intent of the requirement that I am not sure is clear. Increasing the
outdoor air ventilation rate increases the energy used to condition the outdoor
air, so if the intent is to put the onus on Proposed design to show energy
reduction/LEED compliance over the 90.1/62 requirements shouldn't the Baseline
outdoor air be the minimum air flow rate per the ASHRAE 62 calculations? This
puts the onus on the design team to provide a design that compensates for the
increase in energy to meet IEQC2 by providing some method of processing the
increase in outdoor air while still reducing energy consumption.<o:p></o:p></p>
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