[Bldg-sim] About infiltration in a LEED analysis.....

[Nick Caton]

Hi David!

Matching infiltration rates between models is in line with the present LEED requirements and referenced standards.  To my understanding, doing otherwise is not prohibited, but if you wish to differentiate proposed and baseline infiltration rates you will need to furnish an explanation (exceptional calculation) along with the rest of your model documentation to the satisfaction of your LEED EAc1/EAp2 reviewer.

I haven't direct experience submitting such differentiating calculations specifically for LEED review (I hope others can chime in!), but some searching of the term "infiltration" in the onebuilding mailing list archives will lead you to multiple methods/papers/cited sources for different approaches.  I personally reference ASHRAE 2001 Fundamentals to address tightness improvements on a broad level (further explanation/citation in the archives).

Since you mentioned "renovation," I would be extra cautious to review the most current LEED guidance available regarding where and to what extent you apply any such "leakage improvement" factors to infiltration rates - there may be unintended effects on what is expected for the modeled constructions (baseline vs. actual).

Best of luck!

~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
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From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of David GARCIA-SANCHEZ
Sent: Thursday, January 10, 2013 12:16 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] About infiltration in a LEED analysis.....

Hi all,

I'm modeling a building for a LEED certification (renovation) for a building in France.

Normally in my baseline and proposed models I put the same infiltration (n50 = 0.14 ach) for both buildings. Even that this is an unreal case (since the renovation leads to an improve in the permeability of the building).

I do that because, first 0.14 is the minimal infiltration allowed by French regulations, and second because I have never seen in the ASHRAE documentation about improve infiltration in current buildings. Even if the improve of the infiltration rate can make me gain a lot of improvement between baseline and proposed buildings energy requeriements.

Anyone of you have already experience in this specific point? Any justification is required from the USGBC if I want to change the infiltration between baseline and proposed buildings?

Thanks in advance for any comments/help on this,

Regards,
David GARCIA-SANCHEZ

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David GARCIA-SANCHEZ
greenaffair
Tel. +33 (0)1 46 03 08 02
Mobile +33 (0)6 78 15 08 09
102 avenue Edouard Vaillant - 92100 Boulogne-Billancourt
www.greenaffair.com<http://www.greenaffair.com/>



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