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New Air Sealing Requirements in the 2009 International Residential Code

The latest version of the IRC gives you two options: comply with an air-sealing checklist or perform a blower-door test

Posted on Jun 3 2011 by Martin Holladay, GBA Advisor

One of the most cost-effective ways of lowering residential energy costs is to reduce a home’s air leakage rate, so it makes sense for energy codes to ratchet up air-sealing requirements. The latest (2009) version of the International Residential Code does exactly that.

Just like the earlier 2006 code, the 2009 IRCInternational Residential Code. The one- and two-family dwelling model building code copyrighted by the International Code Council. The IRC is meant to be a stand-alone code compatible with the three national building codes—the Building Officials and Code Administrators (BOCA) National code, the Southern Building Code Congress International (SBCCI) code and the International Conference of Building Officials (ICBO) code. includes a requirement (in section N1102.4.1) that “the building thermal envelope shall be durably sealed to limit infiltration.” The language in that section is unchanged; the code still requires that “The following shall be caulked, gasketed, weatherstripped, or otherwise sealed with an air barrierBuilding assembly components that work as a system to restrict air flow through the building envelope. Air barriers may or may not act as a vapor barrier. The air barrier can be on the exterior, the interior of the assembly, or both. material, suitable film, or solid material:
1. All joints, seams and penetrations.
2. Site-built windows, doors and skylights.
3. Openings between window and door assemblies and their respective jambs and framing.
4. Utility penetrations.
5. Dropped ceilings or chases adjacent to the thermal envelope.
6. Knee walls.
7. Walls and ceilings separating the garage from conditioned spaces.
8. Behind tubs and showers on exterior walls.
9. Common walls between dwelling units.
10. Other sources of infiltration.”

New air sealing requirements, with two compliance options

In addition to these provisions, the 2009 IRC includes further air-sealing requirements in section N1102.4.2.

This new section gives builders two options: either the builder must comply with the requirements of an air barrier and insulation inspection checklist (Table N1102.4.2), and submit to a “visual inspection,” or the builder must show that “tested air leakage is less than 7 ACHACH stands for Air Changes per Hour. This is a metric of house air tightness. ACH is often expressed as ACH50, which is the air changes per hour when the house is depressurized to -50 pascals during a blower door test. The term ACHn or NACH refers to "natural" air changes per hour, meaning the rate of air leakage without blower door pressurization or depressurization. While many in the building science community detest this term and its use (because there is no such thing as "normal" or "natural" air leakage; that changes all the time with weather and other conditions), ACHn or NACH is used by many in the residential HVAC industry for their system sizing calculations. when tested with a blower door at a pressure of 50 pascals.”

The checklist option

The items on the air barrier and insulation inspection checklist (see Image 2, below) make sense, although two provisions (the provisions requiring that crawl space walls and the corners of above-grade walls must be insulated) are vaguely worded and therefore ambiguous.

Here’s a partial list of the checklist items:

  • Wall insulation must be “installed in substantial contact and continuous alignment with the building envelopeExterior components of a house that provide protection from colder (and warmer) outdoor temperatures and precipitation; includes the house foundation, framed exterior walls, roof or ceiling, and insulation, and air sealing materials. air barrier.”
  • Wall corners must be insulated. (This is rather vague — do two-stud corners without any exterior foam meet the intent of the code?)
  • The “space between window/door jambs and framing” must be “sealed,” and “air permeable insulation” cannot be “used as a sealing material.”
  • Rim joists, window headers, and door headers must be insulated.
  • Insulated floors (for example, cantilevered floors or insulated floors over garages) must have insulation “installed to maintain permanent contact with the underside of the subfloor.”
  • There is a requirement for crawl space walls that “Insulation is permanently attached to walls.” (This requirement is unclear; it’s hard to tell whether uninsulated crawl space walls — for example, in a ventilated crawl space with insulation between the floor joists — are permitted.)
  • “Showers and tubs on exterior walls” must “have insulation and an air barrier separating them from the exterior wall.”
  • There is a requirement for “electrical/phone box on exterior wall” requiring that the “air barrier extends behind boxes or air sealed type boxes are installed.”
  • “HVAC register boots that penetrate the building envelope” must be “sealed to subfloor or drywall.”

The code states that the items on this list should — “where required by the code official” — be “field verified” by “an approved party independent from the installer of the insulation.” The language leaves some wiggle room, implying that the code official has the discretion to allow a builder to self-certify that these items are complete, or even to waive the checklist requirements altogether.

The blower-door option

If a builder chooses the blower-door option, the bar has been set quite low. While PassivhausA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. builders are aiming for 0.6 ach50, and many energy-efficient builders strive for 1.5 ach50, the building code is satisfied if your home is quite leaky: All you need to show is 7 ach50.

The code is fairly specific about the circumstances of the blower door test. It requires that “testing shall occur after rough-in and after installation of penetrations of the building envelope, including penetrations for utilities, plumbing, electrical, ventilation and combustion appliances.” It also specifies which openings should be open during testing (interior doors), which openings should be closed but not sealed (windows, exterior doors, fireplace doors, dampers), and which openings should be sealed (exterior openings for ventilation systems).

However, the writers of the code provision forgot an important detail: the code is silent about who is allowed to perform the test. As written, the code allows anyone to perform a blower-door testTest used to determine a home’s airtightness: a powerful fan is mounted in an exterior door opening and used to pressurize or depressurize the house. By measuring the force needed to maintain a certain pressure difference, a measure of the home’s airtightness can be determined. Operating the blower door also exaggerates air leakage and permits a weatherization contractor to find and seal those leakage areas.. In fact, builders can conduct their own blower-door tests — in effect, they can self-certify the air leakage rate of the home they are building.

Even though it’s not written there, my interpretation says that it is

In light of this obvious mistake, building code experts are scrambling to present their own interpretations of the new code. One source notes (correctly) that “verification requirements are up to the AHJ” — that is, the “authority having jurisdiction,” otherwise known as your local building official. Of course, that’s true — local code officials have always had broad authority to interpret the code as they see fit.

Similarly, Lynn Underwood, an advisor at GBA, interprets the new code this way: “the locality has the right to accept (or not accept) the individual performing the [blower door] test and evaluation.” According to Michael DeWein, the technical director at the Building Codes Assistance Project, “Most are interpreting it [section N1102.4.2.1] to mean that someone who is qualified must perform the inspection, i.e. a rater, BPI-certified analyst, or shell specialist.”

However, it’s quite possible that some builders will resist the idea of complying with a code “requirement” that doesn’t appear in the code. I see no reason why a builder couldn’t rebut a code official’s insistence that a blower-door test must be performed by a third-party inspector with this simple challenge: “Show me where it says that I can’t do the test myself.”

According to DeWein, at least one state — New York — caught the code error before incorporating sections of the 2009 IRC into the New York building code and included a provision requiring a qualified third-party technician to perform the referenced blower-door test.

Last week’s blog: “Calculating the Global Warming Impact of Insulation.”


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Image Credits:

  1. Martin Holladay
  2. International Code Council

1.
Fri, 06/03/2011 - 06:24

Edited Fri, 06/03/2011 - 06:24.

Georgia requires the Blower Door test
by Allison A. Bailes III, PhD, GBA Advisor

Helpful? 0

It's nice to see the IRC join the IECC in the air-sealing requirements. The state of Georgia last year passed a new energy code (http://hub.am/bPEXiz) that disallows the visual inspection to demonstrate compliance. Every new house must have a Blower Door test.

As for who can do the testing in Georgia, they decided to keep it loose now. Builders can test their own work, but first they have to get certified as Duct & Envelope Tightness (DET) Verifiers (http://hub.am/gR0WJC). It's a start.


2.
Fri, 06/03/2011 - 10:41

Edited Sat, 06/04/2011 - 19:36.

Washington State reqs
by David Meiland

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Washington has its own energy code, modeled on the IECC. The airtightness requirement is not volume based (ACH) but is derived from square footage of floor area. It sets the bar at *roughly* 5 ACH50 for a house with 8-foot ceilings, but houses with higher ceilings get a break because their volume is larger for a given footprint.

I need to check back and see what the AHJ here is requiring as to who does the test. It may be that a builder can self-certify.


3.
Fri, 06/03/2011 - 15:56

State adoption of IRC
by Doug McEvers

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Martin, I thought one of the conditions of accepting DOE Weatherization $ as part of the stimulus package was states accepting funds are required to adopt the latest IRC code. What is the timeline for state adoption of the 2009 IRC , what about 2012 IRC and IECC? I checked energycodes.gov and they are showing about 2/3 of the states adopting 2009 IRC by 2015, sounds kind of pokey. We will have 2 new code cycles by then.


4.
Sat, 06/04/2011 - 08:54

More AHJ
by 5C8rvfuWev

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Allison Bailes said:

"The state of Georgia last year passed a new energy code (http://hub.am/bPEXiz) that disallows the visual inspection to demonstrate compliance. Every new house must have a Blower Door test."

That's fabulous news for me as I'm planning to build here in GA.

But earlier this year two new subdivisions opened locally for buyers in the $300k range. Given the market locally I wondered at the logic and imagined they were doing something "new" -- i.e., up my alley. They had their first open houses in late March, a finished unit and 3 more on the way.

I left disgusted. They were big, and they were all framed and insulated -- without any sign of sealing either in the framing envelope or in the crawlspaces. These are, according to the code revisions Allison witnessed being passed, subject to the 2009 IRC.

This week I plan to stop by the Planning Dept in the same county. While I'm there I think I'll stop by the Code Enforcement office upstairs to ask when their training will begin.

Sheesh.
Joe


5.
Sat, 06/04/2011 - 13:23

As in the case of the TARP
by Edward Palma

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As in the case of the TARP money that was handed out to banks and was not accounted for, so goes much of the money from the Recovery and Reinvestment Act. Many cities around the country received the money without following the mandates, and follow-up supervision and accountability of the funds was lax. In response to Joe, I find your sarcasm regarding code officials a bit disconcerting. As a Building Official in the State of Connecticut (21 years), as well as a Designer and Builder (36 years), an accredited Green Professional with the NAHB, and presently achieving LEED accreditation, it is my opinion that one does not get the result they are looking for with sarcasm and negative criticism.. Joe do the Building Officials in your municipality approach you with a sarcastic, condescending attitude toward your projects, your training, or your certifications and intellect? If they do then they are not doing their job correctly as code officials, educators, and facilitators of the letter and intent of the codes. If they do not, then it makes one appear quite shallow and adversarial presenting a condescending attitude toward them. Primarily though, it does very little in promoting an integrated harmonious process between you and the officials of your local municipality. States are just catching up on the training aspects of the new IRC 2009 & 2012, IECC 2009 & 2012. Building department budgets for code books and training facilities have been devastated by the economy. Adoption of the codes is always behind schedule, and in many instances reactive as opposed to proactive. That is no excuse for any of us not understanding the technical aspects of our jobs. Besides being a builder, what are your credentials? The ICC has offered free training for the IECC 2009 in all states, have you taken it? They even give you a copy of the code book and workbook. Instead of the "sheesh", if you already have not done it, you would be better served to educate yourself in the ICC family of codes. Also maybe you should get accredited in the field of green building through USGBC or the NAHB or one of the many excellent local grass roots organizations found around the country. That would be something "new" and up your "alley". At that point you would be able to speak from an "educated" platform instead of one without any intellectual foundation except negativity and criticism.


6.
Sat, 06/04/2011 - 20:17

reply to Edward Palma
by 5C8rvfuWev

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You asked:

"Joe do the Building Officials in your municipality approach you with a sarcastic, condescending attitude toward your projects, your training, or your certifications and intellect?"

Not at all, Edward. Nor would I ever speak that way to them. On the other hand, I wasn't talking to them but expressing my chagrin that they apparently accepted these traditional (in the sense of inadequate and outmoded) buildings without a fair-thee-well ... nor upgrades in any area. But I will inquire, as I said, because I want to enthusiastically support the direction of the code changes (in case they've been running into reluctance or resistance), and I want them to know that a resident of the county who wishes to build a new home is eager and anticipating the progress which only THEY can assure.

I never said, nor meant to imply, that they have an easy job of it. I know better.

In the interest of disclosure, Edward, I'm sorry if my comment was misleading ... I'm not in any sense a pro -- I'm here at GBA as a consumer with just the learning attitude you suggest I should have. And while I'm not a contractor, or anything more than an amateur who has muddled through other home building adventures, I think as a consumer (and taxpayer) I'm in an ideal position to support, encourage, and even be a little insistent that steps be taken to insure progress and responsible environmentalism ... as specified by code.

I apologize if my comments seemed to dismiss the problems or difficulties of officials or anyone else in the trades as I have nothing but admiration for the skill and knowledge y'all have to be successful. All the same, in my own career I've never been given a "pass" just because I found it hard to adapt to new technology or methods or standards.

Respectfully,
Joe


7.
Sun, 06/05/2011 - 06:03

Response to Doug McEvers
by Martin Holladay, GBA Advisor

Helpful? 0

Doug,
Your impression is basically correct. The energy efficiency funds that were part of the stimulus bill were handed out with the understanding that states would adopt the 2009 IRC, but there really weren't any teeth in the legislation.

The last time I wrote a blog about energy codes, Mike DeWein commented on the issue. “We know that some states have adopted the code but have done nothing to ensure implementation,” said DeWein. “There were great amounts of money in the Recovery Act for energy efficiency — funds that were handed out to all the states. They all took that money. While there wasn’t any great set of teeth to the Recovery Act preconditions, it was understood that the states were supposed to adopt the 2009 code and meet compliance goals by 2017."


8.
Sun, 06/05/2011 - 11:37

Inspectors
by David Meiland

Helpful? 0

The building inspectors here were able to get a day's worth of training on the new energy code requirements, including blower door testing, courtesy of Washington State U's energy program, which has done the same thing many other places in the state. While I agree they should know the latest and greatest, I do not envy them the task of trying to educate builders and others on how to build better buildings. I find myself in that position sometimes now, and there are a lot of guys out there who don't want to do anything differently, no matter how easy or important it is.


9.
Sun, 06/05/2011 - 12:31

Inspectors, Builders, and other Blind and Broke parties
by Ted Clifton

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I have been teaching classes for the last year and a half on how to comply with the new codes here in Washington State. To date, only a handful of builders have taken the classes, and even fewer code officials. The problem seems to be two-fold; most builders don't have a new home to build right now, so the codes are strictly academic, and the local jurisdictions don't have the funds to send what staff they have left (which is less than half what they had two years ago) to take the classes.
Many builders seem totally unaware that there have been changes to the code that will significantly impact they way they do business. Whenever the economy starts to turn around, and builders start building homes again, I expect to see huge (but hopefully ineffective) push-back on the new blower-door requirements, and many other elements of the new codes. For now, ignorance seems to be bliss.


10.
Sun, 06/05/2011 - 12:47

Air sealing for fun and profit
by Doug McEvers

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Ted,

I have a different take on the new housing slowdown and the adoption of more restrictive energy codes. More and more I see the large production builders offering energy efficiency packages for new homes. The market is so tight and buyers so fickle, energy efficiency is viewed as a marketing advantage. If new home buyers equate efficiency with quality construction this puts the builder in a stronger selling position.


11.
Tue, 06/07/2011 - 22:47

Marketing advantage, or lip service?
by Ted Clifton

Helpful? 0

Doug,

I see the same thing you do, almost. I see the big builders paying lip service to energy efficiency, while continuing to do what they always do best, build the same old stuff for the lowest possible cost. I will grant you that there are a select few big builders doing an outstanding job of cranking out very high quality, very energy efficient homes, but these are the exception, not the rule. We have not yet done a good enough job educating homeowners on what they should be able to expect in the way of energy efficiency to really see that change.


12.
Wed, 06/08/2011 - 17:28

codes & air barriers
by Forrest Fielder

Helpful? 0

Professional code officials understand that educating the public is as much of a responsibillity as educating staff'. Builders will cooperate willingly if they're 1)given time to adjust pricing and contracts and train trade partners, 2)able to pass increased costs on to consumers, and 3)not subject to unnecessary delays. These are reasonable expectations, and code officials can facillitate them all. Testing of systems, and the authority to set the testing conditions and other requirements, are settled policy familiar to building inspectors in most places, and the disincentives for providing fraudulent test results are substantial. Traditionally, the one-time owner-builder is a much more problematic player than professional contractors.
Forrest Fielder, CBO
Phoenix, AZ


13.
Wed, 06/08/2011 - 17:38

Code required blower door tests (and duct leakage tests)
by Kevin Hanlon

Helpful? 0

All, Good string of comments on the state of IECC 2009 code adoption and enforcement. Since 7ACH50 is the (huge, except in the case of very small houses.) leakage metric, someone has to figure out the accurate volume of the house that's being tested. Personally, that's no easy task for lg custom homes w/ vaulted ceilings, dormers and so forth. Is the basement or conditioned attic volume included? As a rater, I follow RESNET guidelines, but what about those doing testing that don't know the guidelines. Also, Don't forget the 09 also requires duct testing when any portion of the ductwork is outside of conditioned space.


14.
Tue, 06/14/2011 - 08:35

Edited Tue, 06/14/2011 - 08:44.

The code compliance path does not fork, sometimes.
by T.C. Feick

Helpful? 0

First, I think that the testing option should be the only option. Few things impact energy efficiency as drastically as air sealing, and none as effectively for the dollar spent. The fact is, even in high enforcement areas, such as mine (southeastern Pa), Chapter 11 is not fully enforced. For instance, If ducts are installed in non-conditioned space, R-8 ductwork is required and so is a duct blaster test (N1103.2.2 #1.) I have seen the R-8 ducts, but I talk to a lot of builders, inspectors, and building performance specialists in the course of a day, and testing is not widely enforced. So, if enforcement is stepped up on at least thes homes with ducts in attics, basements or crawls, then I see this as the perfect opportunity to sell the testing path of the envelope (blower door) as the proper equipment will likely already be on site. This is probably the single most important item in the IRC that can affect real change to building performance. Once builders get used to air leakage testing, the 7ach50 number can be revised downward. Visual inspection will never be able to do this.
Secondly, as a point of clarification to an earlier post, New York does not adopt IRC in its entirety, but publishes their own statewide building code (through ICC), which looks a lot like IRC for residential construction.


15.
Mon, 09/26/2011 - 13:09

Blower door test washington state
by Frank Keeler

Helpful? 0

There is a lot of good information on this site but for someone like myself that wants to do some of his own work building a house it all sound like a catch 22. You have to hope the person you get to do the blower door test (if you can find one) wont gouge you because you are completely at their mercy. It is in my best interest to build a sound cost effective house but having to depend on a certified technician that is also in the business of charging you to “fix the problems” is like the fox watching the hen house. From what I can see in Washington state the fees for test range for 75$ plus 50$ per hour to fix problem to 250$ to set up the test, and to fix the problems with rates up to thousands of dollars. Its like the State of Washington is more interested in looking like they doing something rather then adjudicating the problems with the millions of older housing that are leaking heat like a screen door i.e. an academic 2 dimensional solution to a 3 dimensional problem. It’s new construction and ultimately the new consumer that will pay the bill.


16.
Mon, 09/26/2011 - 13:14

Response to Frank Keeler
by Martin Holladay, GBA Advisor

Helpful? 0

Frank,
Although it's certainly possible to build a house without conducting a blower-door test, such houses are usually leaky and expensive to heat and cool. Investments in air sealing and testing ultimately pay for themselves in lower energy bills.

In many parts of the country, the cost of blower-door testing is subsidized for builders enrolled in the Energy Star Homes program. In some areas, blower door tests are free for Energy Star builders. You should contact your local Energy Star Homes program representative to see if such subsidies exist in your area.


17.
Tue, 09/27/2011 - 07:44

Edited Tue, 09/27/2011 - 07:47.

Cant budget for cost
by Frank Keeler

Helpful? 0

My wife and I have decided not to apply for a building permit at this time thank you all for your input but because of the uncertainties of the law and our inability to budget for the costs we just can not go forward. From what we can gather the cost for the blower door test is between 150 and 500 per test but there is no limit to how many times we will have to have the test to comply 1, 2, 5 no one can say. Then there are cost for foam caulk tape to seal and labor to seal every crack according to the state of Washington’s new energy code 502.4. plus the upgrade of all doors and windows the uncertainties of cost is just to great. The project is scary enough with out the thought of spending weeks and thousands of dollars on test after test its all to much. This to me signals the end to the owner / builder because of the inability to budget for ramifications of unforeseen number of tests.


18.
Tue, 09/27/2011 - 08:00

Edited Tue, 09/27/2011 - 08:04.

Response to Frank Keeler
by Martin Holladay, GBA Advisor

Helpful? 0

Frank,
Like you, I am an owner/builder. To build a house, you either have to learn certain skills -- mixing concrete, rough carpentry, roofing, and air sealing -- or you have to hire a contractor who has those skills. And yes, you have to budget for all of these things.

If your budget isn't quite large enough for a home-building project, that's perfectly understandable. But the problem isn't the blower-door test. After all, the blower-door test is designed to help you lower costs, because the test will result in an energy-efficient building that will save you money for years.

Perhaps you can design and build a smaller, more affordable house. If you do, be sure to build it tight! You'll be glad you did.


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