[Bldg-sim] Air leakage, LEED, and Appendix G of ASHRAE 90.1

Andy hoover andyhoover at thebestconsultant.com
Tue Aug 25 16:50:03 PDT 2009


Air leakage reduction of the entire envelope has been brought up on a number
of occasions to the ASHRAE 90.1 committee and to various LEED staff/groups
by a number of people, including me.

 

I believe that the problem is far more fundamental than having a standard
and being able to model changes accurately and more encompassing than
perhaps the focus of these postings.  I personally have never seen one
building, including LEED certified, that when even grossly inspected meets
requirements for air leakage/infiltration let alone a tighter goal.  I am
sure some exist but 10 buildings in the country will not get us there.  It
would be interesting to see ASHRAE measure their new and improved
headquarters air leakage without undertaking a project to tighten it up
first. 

 

The problem is virtually no buildings are built or most certainly none are
remodeled with the inspections and testing necessary to the envelope and
mechanical systems to meet current requirements.  Most designs do not seem
to comprehensively manage air and vapor and certainly do not require proof.

 

At the very least there should be a requirement of provable inspection and
spot barrier testing and a requirement that every building must have the
envelope commissioned prior to issuing an occupancy permit.  This would
drive huge energy savings, carbon reduction, money savings, and reward
material manufacturers and contractors who make it right and build it right.
Owners can not know what they do not know so they have no awareness of the
impacts.  We have actually been involved in projects where a new roof system
is installed that is tight and better insulated and people notice an
increase in the breezes at exterior walls as what used to go out the top now
goes more out the sides.

 

You can get LEED certified (pick a level) and an occupancy permit with
virtually every gasket in your windows/curtain walls leaking air/vapor/even
running water (not performing) with finger size gaps at plenum joints, and,
no air/vapor barrier connection between a buildings’ façade and roof systems
but not with a 2 foot square single pane window, crazy.

 

The NIST study and others show that new buildings at the time the studies
were done did not meet code let alone some stricter goal.

 

It is not that the materials and construction processes do not exist.  It is
that to do it right costs more, so it can be done, but not without the
proper inspections and testing.

 

 

Andy Hoover

Principal

The BEST Consultant, Inc.

Office: 678-200-7648

Fax:678-827-0574

Cell: 678-793-1159

 

www.thebestconsultant.com

 

 

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From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Paul Grahovac
Sent: Tuesday, August 25, 2009 1:43 PM
To: Sam Mason; bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Air leakage, LEED, and Appendix G of ASHRAE 90.1

 

Sam Mason

Atelier Ten

 

6 derives from 1 -5.

 

7 is from the person who submitted the change proposal.

 

Paul Grahovac, LEED AP

 

  _____  

From: Sam Mason [mailto:sam.mason at atelierten.com] 
Sent: Tuesday, August 25, 2009 12:35 PM
To: Paul Grahovac; bldg-sim at lists.onebuilding.org
Subject: RE: [Bldg-sim] Air leakage, LEED, and Appendix G of ASHRAE 90.1

 

Paul,

Where did you get your information regarding number 6 and 7?

 

Sam

 

--

Sam Mason

Atelier Ten

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Paul Grahovac
Sent: Tuesday, August 25, 2009 11:14 AM
To: David S Eldridge; bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Air leakage, LEED, and Appendix G of ASHRAE 90.1

 

1.      Recent posts to this listserv show that air leakage reduction is
successfully modeled in the UK.

 

2.      “The LEED point system drives designers to reduce the HVAC system
down to the optimal level.”  US Green Building Council LEED training, May
27, 2004, Dallas, Texas.

 

3.      Melding the data from across the US, air barriers would reduce
building natural gas consumption by greater than 40% and electrical
consumption by greater than 25%.  National Institute of Standards and
Technology, “Investigation of the Impact of Commercial Building Envelope
Airtightness on HVAC Energy Use, NISTIR 7238.

 

4.      Air barriers, if modeled under LEED, would reduce HVAC construction
costs.

 

5.      “There are barriers to implementation of radiant systems in North
America. One is that engineering fees are based on a percentage of the
mechanical and electrical construction budget. The lower the cost of these
systems, the lower the engineer’s fee.”  Geoff McDonell, P.E., senior
mechanical engineer in the Burnaby, British Columbia, office of Earth Tech’s
Global Facilities and Infrastructure division.

http://www.facilitiesnet.com/hvac/article/Windows-Pave-Way-For-HVAC-Innovati
on--1476  

 

6.      ASHRAE engineers have a financial incentive not to allow air leakage
reduction to enter into LEED point calculations.

 

7.      A change proposal to allow modeling of air leakage reduction has
been pending with the ASHRAE 90.1 simulation group for five months without
any action – and without any hope of action in the future.

 

Paul Grahovac, LEED AP  

 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of David S
Eldridge
Sent: Monday, August 24, 2009 1:49 PM
To: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Air leakage, LEED, and Appendix G of ASHRAE 90.1
(Return of a Hornet's Nest?)

 

First, I feel that the statement that EAC1 methodology “penalizes air
barrier suppliers” and “rewards concrete block producers” is completely
off-base.  These are not either/or technologies.  There are many other
factors going into the selection of these items besides energy performance.
If there is real energy and maintenance savings justification as an
investment, then owners will consider it even without contributing to EAC1.
LEED covers many things, but it isn’t an exhaustive manual of
sustainability.  As well, the LEED process, although growing, still covers
only a small fraction of new building projects, regarding Appendix G
applicability.  This is an energy modeling forum, so let’s focus on the
Appendix G part of the discussion.

 

Specifically for 90.1 energy performance, it isn’t a matter of arbitrarily
accepting one or the other – we as an energy modeling community have many
years of experience and research involved in accurately modeling the heat
transfer in envelope components.  The capability of various modeling
techniques have been demonstrated to be capable of relatively accurate
modeling of the differences between thermal mass and insulation levels for
many years, therefore these calculations are included in the standard as a
path of calculating energy usage and savings between alternatives.

 

The modeling software are generally able to predict what would happen due to
a given change in level of infiltration.  The modeling improvements need to
be made in the area of showing that the calculations are accurate in
determining those levels, rather than using a specified reduction.  Does the
software available have the needed parameters to model a product such as
yours?  On a case-by-case basis you may be able to show that you know all of
the needed parameters to make these calculations.  I’m not sure if you could
apply these to all projects, and all software packages though.  For
instance, do you feel that your product has different effectiveness than
other brands?  How would someone capture these differences in efficiency in
eQuest or EnergyPlus?  Would it be okay with the USGBC to propose a straight
percentage reduction?  What’s the starting point for the base case?  How
much variability is there in the construction process?

 

Your input would be welcomed if you offer some expertise in these areas.

 

You mention a study that shows benefits in many cases for 116 buildings (and
common sense would agree with this).  Some focus should be on educating
designers to use the strategy and contractors on proper installation,
regardless of the “points” that are achieved, and under what conditions the
strategy would be most effective.

 

Just my $0.02.  

 

David

 

____________________________________________________________________________
________________________________________

 

David Eldridge, PE

LEED® AP, HBDP


Grumman/Butkus Associates | 820 Davis Street, STE 300 | Evanston, IL 60201 |
Ph: (847) 328-3555, ext 224 | Fax: (847) 328-4550

 

Energy Consultants and Design Engineers
____________________________________________________________________________
________________________________________

 

 

 

 

 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Paul Grahovac
Sent: Monday, August 24, 2009 8:55 AM
To: sheffer at energyopportunities.com; bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Air leakage, LEED, and Appendix G of ASHRAE 90.1

 

I am sure there is just as much baseline for air leakage reduction benefit
as there is for the concrete walls and wooden studs that the User’s Manual
says can be modeled and their energy savings captured for inclusion in the
overall modeling results.

 

I cannot accept that the USGBC and ASHRAE can arbitrarily say reduction in
air leakage will not be considered, but that increases in thermal mass
energy-savings from using concrete walls or energy benefits from using
wooden studs will be used to compute building energy performance.  This
obviously rewards concrete block producers and wood stud suppliers and
penalizes air barrier suppliers.  

 

I’m reminded of Lord Acton’s famous observation:  “Power corrupts, and
absolute power corrupts absolutely.”  Fortunately, even the power of
organizations like ASHRAE and USGBC are subject to some ultimate check.
Such organizations are prohibited by law from arbitrary practices that favor
one group over another.  Below are excerpts from the leading United States
Supreme Court case on the subject. 

 

Paul Grahovac, LEED AP

 

American Society of Mechanical Engineers. Inc. v. Hydrolevel Corporation, 

456 U.S. 556, 102 S.Ct. 1935, 72 L.Ed.2d. 330

(1982), Supreme Court Justice Blackmun, writing for the majority:

 

“Furthermore, a standard setting organization like ASME can be rife with

opportunities for anti competitive activity. Many of ASME's officials are

associated with members of the industries regulated by ASME's codes.

Although, undoubtedly, most serve ASME without concern for the interests of

their corporate employers, some may well view their positions with ASME, at

least in part, as an opportunity to benefit their employers. When the great

influence of ASME's reputation is placed at their disposal, the less
altruistic of

ASME's agents have an opportunity to harm their employers' competitors

through manipulation of ASME's codes.”

ID.., at 571, 102 S.Ct., at 1946.

 

In American Society of Mechanical Engineers, the U.S. Supreme Court affirmed
a jury

verdict that awarded treble damages to the company that was injured by
certain members of the

trade organization that had manipulated the trade organization and its role
in the industry to set

standards designed to enrich those members' corporation and diminish the
ability of its

competitors to fairly compete in the marketplace. In deciding to hold the
trade organization

responsible for the actions of its members, the Court explained:

 

“It is true that imposing liability on ASME's agents themselves will have
some

deterrent effect, because they will know that if they violate antitrust laws
through

their participation in ASME, they risk the consequences of personal civil
liability.

But if, in addition, ASME is civilly liable for the antitrust violations of
its agents

acting with apparent authority, it is much more likely that similar
antitrust

violation will not occur in the future. "Pressure will be brought on the

organization to see to it that its agents abide by the law." United States
v. A&P

Trucking Co., 358 U.S. 121, 126, 79 S.Ct. 203, 207, 3 L.Ed.2d 165 (1958).
Only

ASME can take systematic steps to make improper conduct on the part of all
its

agents unlikely, and the possibility of civil liability will inevitably be a
powerful

incentive for ASME to take those steps. Thus, a rule that imposes liability
on the

standard setting organization- which is best situated to prevent antitrust
violations

through the abuse of its reputation-is most faithful to the congressional
intent that

the private right of action deters antitrust violations.”

14:., at 572-573, 102 S.Ct., at 1946.

 

 

 

  _____  

From: Marcus Sheffer [mailto:sheffer at energyopportunities.com] 
Sent: Monday, August 24, 2009 8:22 AM
To: Paul Grahovac; bldg-sim at lists.onebuilding.org
Subject: RE: [Bldg-sim] Air leakage, LEED, and Appendix G of ASHRAE 90.1

 

As I understand it the issue is that the 90.1 Standard does not establish a
base line condition for air leakage so no savings can be claimed.  I
certainly agree that the savings are real and should be counted.  I know
that the Appendix G committee has this issue on their extensive “to do”
list.

 

Marcus Sheffer, Chair – USGBC EA TAG

7group

 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Paul Grahovac
Sent: Wednesday, August 19, 2009 7:00 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Air leakage, LEED, and Appendix G of ASHRAE 90.1

 

The National Institute of Standards and Technology (NIST) did an extensive
study documenting a greater than 40% natural gas savings and a greater than
25% electricity savings across the nation for building energy consumption if
buildings were uniformly constructed with air barrier systems installed.
They evaluated 116 existing buildings and computer modeled several different
building types.  The purpose of their study was to provide information to
ASHRAE concerning whether it would be desirable to add an air barrier
requirement to ASHRAE 90.1.

 

As a result, I’ve always thought that Appendix G to ASHRAE 90.1 allows you
to change the air leakage rate off the default and onto a rate corresponding
to an air barrier installation, so that you could claim LEED points for the
corresponding energy savings.  However, an architect at a presentation I did
said you could not do that under the LEED and ASHRAE requirements.  (I know
the models will do it, because I’ve done it on the TRANE model and obtained
results that support the NIST findings.)

 

I see in Appendix G that:  “G3.1.2.5. Ventilation.  Minimum outdoor air
ventilation rates shall be the same for the proposed and baseline building
designs.”  However, I searched the document for “outdoor air ventilation”
and the phrase occurs only in the context of mechanical systems that are
designed to intentionally bring air into the building.  If this section is
the basis for concluding that air leakage barriers should be left out of the
modeling, then I have trouble understanding why.

 

Appendix G says that all components of the building are to be modeled as
designed.  That would preclude modeling as if an air barrier system did not
exist in the design.  It says the baseline building model is to have
steel-framed above-grade walls, and it is silent about the design building,
but the User’s Manual says that if the design building walls are block or
cast concrete, then “the mass is credited in the building performance rating
method.”  Likewise, if the walls are wood stud instead of steel, then the
Manual says credit is given for the superior energy performance of wood
frame versus steel frame.  The User’s Manual states that it:  “Offers
information on the intent and application of Standard 90.1.”  Given these
examples in the Manual based on existing thermal mass energy-saving data and
wood-versus-steel stud energy data, it is difficult to conclude that a wall
that is constructed with materials meeting the air leakage limits and
installation requirements of the Air Barrier Association of America and
determined to produce significant energy savings by the NIST study based on
those same limits and requirements should be modeled as if it leaked air
like a building without an air barrier. 

 

Please let me know what you think, and if you know of any reason why it is
not proper to change the air leakage rate through the building envelope in
the design model to show the benefit of air barriers.

 

Thanks,

 

Paul Grahovac, LEED AP

R-GUARD Air & Water-Resistive Barrier Product Manager

PROSOCO, Inc.

3741 Greenway Circle

Lawrence, Kansas  66046

(785) 830-7355

(888) 376-3417 fax

pgrahovac at prosoco.com

web site  http://www.prosoco.com/

 

 

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