[Bldg-sim] Building Infiltration

Bishop, Bill bbishop at PathfinderEngineers.com
Wed Mar 11 06:26:05 PDT 2009


ASHRAE Proposed Standard 189.1P Standard for the Design of
High-Performance Green Buildings Except Low-Rise Residential Buildings
contains air barrier requirements in Normative Appendix B, attached. The
public comment period of this draft ended last April, but I found a copy
here:
http://www.sanantonio.gov/Mayor/EnvironmentalPolicy/attachments/ASHRAE%2
0189%20Public%20Review.pdf
 
Air leakage testing is one of three options for compliance. The other
two are using pre-approved materials or assemblies.
 
Regards,
Bill
 
William Bishop, EIT, LEED(r) AP | Pathfinder Engineers LLP
Mechanical Engineer
 
134 South Fitzhugh Street
Rochester, NY 14608
T: (585) 325-6004 Ext. 114
F: (585) 325-6005
bbishop at pathfinderengineers.com
 
www.pathfinderengineers.com
P Please strive to live sustainably.
________________________________

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of James V.
Dirkes II P.E.
Sent: Wednesday, March 11, 2009 7:37 AM
To: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Building Infiltration
 
Andy, you're right on!  Doug is also spot on re: LEED EBOM.  EBOM
actually measures results, something LEED-NC cannot do because it's
models aren't built yet.
 
Infiltration calcs have always been a thorn in the side of anyone
calculating heating / cooling loads since they're so dependent on actual
construction practice (not to mention the effects of aging, settling,
etc.)  In theory, a savvy building owner will continue to pay attention
to energy use over the life of the building and observe rising energy
use that's well-correlated to infiltration -- then fix it.  
 
That's a rare owner, I know!
 
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 Andy hoover
	Sent: Tuesday, March 10, 2009 8:13 PM
	To: 'C. J. Gann'; 'Todd Lagus'; 'Karen Walkerman'; 'Mark Prince'
	Cc: bldg-sim at lists.onebuilding.org
	Subject: Re: [Bldg-sim] Building Infiltration
	In addition to what Craig says below the very idea that it is
okay to blow energy out of the building or suck in unconditioned air at
a high, variable, uncontrolled rates due to high leakage through the
envelope in both directions dependent upon pressure differentials  is
certainly not very 'green' or energy saving at the least and we feel
contributes to much higher energy use than necessary and we know it
contributes to higher maintenance costs and lowered useful life of
building envelope components.  Because it is not easy, is not something
that HVAC manufacturers/companies/ ASHRAE can contend with, and requires
knowledgeable on site inspection during construction/remodel/repair it
does not get the attention it deserves.  My belief is that it is a
significant contributor to why modeling software does not match up well
with reality.
	 
	Furthermore, someone please take me to any existing 10 (heck 5)
story or taller  building that does not desperately try to suck in air
low and spew it out high and any low rise with meaningfully controlled
building envelope conditioned air management.  It is almost impossible
to find complete vapor barriers where they need to be at wall/roof
interfaces let alone the rest of it.
	 
	We have seen these same issues in LEED certified, yes certified,
new buildings as the reward is low for actual building envelope air and
moisture penetration control (versus showing a design and calculation
that shows it is low) and no one is interested in inspecting and making
sure the work is done to meet LEED, heck even base code, requirements
because so far there is zero penalty (LEED, code, GBI, or anyone else).
The energy savings for existing buildings can be significant and the
lowered repair and maintenance costs for the building envelope are
significant if air and moisture penetration are controlled but the
emphasis is certainly not there most of the time.  
	 
	My feeling is that we absolutely should reward with LEED points,
attaboys, smiles, pats on the back, tax credits, and everything else we
can things done to existing buildings that increase the useful life of
components, lower environmental impact, lower maintenance requirements
and costs, and decrease energy usage.  I thought that is what the goals
were, ACTUAL lowered environmental impact in all ways and lowered costs.
Building envelope infiltration gets only lip service and design but
there are no inspection standards and accountability to prove the work
is done appropriately.
	 
	 
	Andy Hoover
	Principal
	The BEST Consultant, Inc.
	Office: 678-200-7648
	Fax:678-827-0574
	Cell: 678-793-1159
	 
	www.thebestconsultant.com
	 
	From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of C. J. Gann
	Sent: Tuesday, March 10, 2009 2:01 PM
	To: 'Todd Lagus'; 'Karen Walkerman'; 'Mark Prince'
	Cc: bldg-sim at lists.onebuilding.org
	Subject: Re: [Bldg-sim] Building Infiltration
	 
	Here's my take on it. The baseline building envelope on a
renovation is supposed to be modeled in the pre-renovated condition.
This would include wall and window thermal properties (U, SHGC, etc.) as
well as infiltration estimates. The proposed design would incorporate
all changes and improvements to the envelope and be modeled as such. It
should be noted however that Section 5.4.3 of 90.1-2004 contains
mandatory provisions for air leakage so the proposed design must at
least meet the mandatory requirements.
	 
	It is unrealistic to assume a positive pressurization strategy
eliminates infiltration. Keep in mind infiltration occurs due to the
vapor pressure and air pressure differences across the envelope. During
unoccupied periods fans usually do not run so a positive pressurization
strategy will not work if fans are off. During the evenings and weekends
the vapor pressure will equalize from inside to outside bringing in any
vapor in this air. Blower door tests are not practical for most
commercial buildings due to the large volume of air movement required to
create a pressure differential. Central AHU supply and exhaust fans
could be used with DDC controls to measure air leakage provided flow
measuring instrumentation was installed.
	 
	Regards,
	
	Craig J. Gann, P.E.
	 
		-----Original Message-----
		From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Todd Lagus
		Sent: Tuesday, March 10, 2009 9:45 AM
		To: Karen Walkerman; Mark Prince
		Cc: bldg-sim at lists.onebuilding.org
		Subject: Re: [Bldg-sim] Building Infiltration
		While I agree that there is oversight in not giving
credit to reduce infiltration, I do not feel like LEED credit should be
given if there isn't an established baseline.  Say, for example, the
building infiltration was exceptionally poor.  Improving the building to
even average infiltration performance may have a large effect on the
energy model, and LEED points would be given for a building that may or
may not deserve it.  While improving the infiltration issue saves energy
for the owner, there is no guarantee that the building does not perform
poorly.  Maybe there should be a LEED "most improved" award which uses
existing conditions as the baseline.
		 
		Todd Lagus, EIT
		Mechanical Engineer
		Sebesta Blomberg 
		sebesta.com | P  651.634.7236 | F  651.634.7400
		 
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		From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Karen
Walkerman
		Sent: Tuesday, March 10, 2009 9:33 AM
		To: Mark Prince
		Cc: bldg-sim at lists.onebuilding.org
		Subject: Re: [Bldg-sim] Building Infiltration
		 
		There aren't any.  There are a few standards that have
infiltration baselines.  I believe the HERS (Home Energy Rating System)
uses an infiltration baseline of about 0.35-0.4 ACH, and there are some
other standards out there.  Of course, some people will argue that the
building should be positively pressurized so that there will be no
infiltration.  I don't know of anyone that has gotten credit for LEED EA
C1 for infiltration, but in my opinion, this is a huge Appendix G
oversight.  My suggestion is to apply for a CIR and suggest an
infiltration baseline.  If the building is 100% renovation, the baseline
could be established using a blower door test on the original building,
or you could come up with another reasonable, established baseline.
		
		--
		Karen
		On Tue, Mar 10, 2009 at 10:16 AM, Mark Prince <
mprince at aeieng.com> wrote:
		Hello,
		
		I'm involved with a project that is considering pursuing
LEED certification.  It is a remodel/renovation of an existing office
building.
		
		The existing office building has quite a bit of
infiltration.  As part of the renovation process, the exterior walls are
being sprayed with a foam insulation that will significantly reduce this
infiltration.  Someone has asked the question, if we can take credit for
this reduction in infiltration.  In other words, they want to model the
Appendix G baseline building with the old infiltration rate and model
the proposed building with the new infiltration rate.  This will show a
good amount of energy cost savings.
		
		Is this acceptable?  I'm having a difficult time finding
any reference to infiltration rates within Appendix G.
		
		Thanks,
		
		Mark Prince
		Affiliated Engineers
		5802 Research Park Blvd.
		Madison, WI 53719
		(608) 441-6668
		mprince at aeieng.com
		
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