[Bldg-sim] Infiltration

[James V Dirkes II, PE]

Amen to that!

 

Stated another way, almost anyone who thinks they know (with any precision)
the infiltration rate of any building is misinformed.

 

Thanks, Chris, for the references.  I was unfamiliar with them, probably due
to giving up hope for any accurate way to estimate infiltration long ago.  

 

That said, more effort is being spent on understanding and reducing
infiltration in recent years and, while the estimation of infiltration may
not improve, the construction practices which allow infiltration may very
well improve as a result!

 

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

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Chris Balbach
Sent: Thursday, July 01, 2010 5:57 PM
To: 'Nick Caton'; 'Vinay Devanathan'; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Infiltration

 

Vinay et. al:

 

Understanding and Estimating Large Building Infiltration.... One of those
'Defense of the Dark Arts' courses at Hogwarts!

 

Reminds me of a quote from Donald Rumsfield: "... because as we know, there
are known knowns; there are things we know we know. We also know there are
known unknowns, that is to say we know there are some things we do not know.
But there are also unknown unknowns - the ones we don't know we don't know"

 

Chew on that one for awhile...

 

If there was such a course, I'd recommend the attached pdf be in the list of
required reading.. If nothing else it's a gold mine refererence for
explaining to your client why 'measuring' infiltration rates in his/her
building, while theoetically possible, it most likely would require an
ENORMOUS amount of cash and airflow to generate a meaningful "reference
pressure". This document is "solid" on the fundamentals. 

 

So, if you want to do it 'right' - this pdf will help you correctly specify
a infiltration measurement test procedure to be performed by a qualified
'Testing Agency. I'd bring several bags of cash with me.

 

The fallback here that many of us may find useful are the 'standards' tables
on pages 5, 6, and 7. If you don't measure, you will have to estimate, and
atleast these 'standards' will give you a sense of how 'non-standard' your
final estimate is.. We have to work with what we have.. 

 

ASHRAE's RP-935: "Protocol for Field Testing of Tall Buildings to Determine
Envelope Air Leakage Rate" - (Available free to ASHRAE members through the
ASHRAE bookstore) is another good reference to get familiar with possible
methods for better understanding the "known unknowns".... As for the
"unknown unknowns" - thank god for ASHRAE research. 

 

 

All the Best,

 

_Chris

 

Chris Balbach, PE, CEM BEMP, CMVP

Vice President of Research and Development

Performance Systems Development of NY, LLC

124 Brindley Street, Suite 4, Ithaca NY 14850

http://www.psdconsulting.com

ph: (607)-327-1647

 

 

 

 

  _____  

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Nick Caton
Sent: Thursday, July 01, 2010 5:14 PM
To: Vinay Devanathan; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Infiltration

That's typical in my experience.

 

Infiltration is figured primarily based on temperature and pressure
differential (wind speed vs.interior pressurization) across an exterior
surface, among other things.  Lacking any exterior surfaces, I would presume
any "interior cross-zonal infiltration" is generally negligible, unless you
might be dealing with a large positively pressurized unconditioned space.?

 

~Nick

 

cid:489575314 at 22072009-0ABB

 

NICK CATON, E.I.T.

PROJECT ENGINEER

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

Check out our new web-site @ www.smithboucher.com 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Vinay
Devanathan
Sent: Thursday, July 01, 2010 2:57 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Infiltration

 

Hello,

While performing energy modeling, I am guessing it is enough if we account
infiltration just for the zones in contact with the exterior environment? Am
I right?
Or do we have to include interior zones in infiltration calc?

Thank you.

Regards,
Vinay

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