Below is the text version of the Building America webinar, "Air Sealing Best Practices and Code Compliance for Multifamily Area Separation Walls." Watch the webinar.

Linh Truong:
Hello, everyone. I'm Linh Truong, with the National Renewable Energy Laboratory, and I'd like to welcome you to today's webinar, hosted by the Building America Program. We are excited to have Pam Cole, with Pacific Northwest National Laboratory, Ari Rapport, with IBACOS, and Robby Schwartz, with EnergyLogic, here today to discuss air sealing's best practices and cod3 compliance for multifamily area separation walls.

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Before I begin, I will provide a short overview of the Building America program. Following the presentations, we'll have a questions and answer session, and closing remarks. So for more than 20 years, the U.S. Department of Energy Building America Program has been partnering with industry to provide cutting-edge innovation and resources to market. And now for today's presentations. Our webinar today is "Building America: Air Sealing Best Practices and Code Compliance for Multifamily Area Separation Walls."

Our first speaker today is Pam Cole, who is a building energy scientist and a researcher at Pacific Northwest National Laboratory. Ari is a program manager at IBACOS. And Robby founded EnergyLogic in 2016 and is the director of builder relations. With that, I'd like to welcome you, welcome the first speaker today. Pam?

Pam Cole:
Thanks, Lin. Before we begin to the actually presentation, this is a webinar that or the first time that Building America, one of the first times that we're going to offer AIA and ICC continuing education credits. So this is just a little bit of information if you are an architect, and an AIA member, you will be allowed to provide your information back to us with your AIA member number, and we'll submit credit for you to AIA, and then you can check back in a week or so, and check your transcript for that, for those credits.

If you are certified through ICC, if you're a code official, and you're an ICC member, and need a renewal of your certifications, we are going to be offering ICC CUs, as well. And with that, we will have a link at the end of this webinar. You'll need to take down that link. And then you'll submit your name for a certificate of attendance for today's webinar. And we will – you will actually have to submit your work certificate and documentation to ICC directly. For the rest of you that actually are with a professional organization, you can use the certificate of completion for today's webinar and submit it directly to your affiliate, and receive credit that way, if they'll allow you to submit your certificate of attendance.

Next slide. So little bit about the course description today is that we have Ari and Robby that will be doing a lot of the talking on air sealing of area separation wall assemblies. A little bit of the details about the code requirements, what's involved in an area separation wall, and then getting into some of the barriers with the codes. And then what's going to be happening, our next steps as far as resolving some of those. And then some resources for you on items that are available to help you as far as dealing with area separation walls and code compliance if you're having issues right now in multifamily buildings.

Next slide. So learning objectives for today's webinar are we want to make sure you get an understanding of what the constituents of a UL fire rated assembly is. Understanding the disconnect between the fire code and the energy code for area separation walls. Applying best practices for air sealing area separation walls in multifamily buildings. We have a lot of good information on the solution center, and we'll show you where that information is located. And then lastly, how to demonstrate compliance for multifamily buildings. When you're dealing with air sealing and these type of walls, the air leakage requirements for them, as well.

Next slide. So I would like to turn it over to Robby, who's going to go into more detail about the area separation walls. Robby, go ahead and take it away.

Robby Schwarz:
thank-you, Pam. Uh. The heart of the matter with regard to area separation walls is keeping fire from one side of the assembly to going to the other of the assembly. And really when we're talking about area separation walls, we're talking about walls that are separating townhomes, duplexes, next slide please, and we're looking at – we're looking basically at this Shaftliner assembly that's displayed here. So this will be the heart of what we'll be discussing today, is this type of assembly. Next slide.

So, again, we want to talk about what constitutes a UL fire rated assembly. We'll be looking at what this assembly is being asked to do from a fire perspective, from a sound perspective, and from an energy perspective. Again, what's the disconnect between fire code and energy code? And across the country, why is the assembly being built slightly differently? Next slide. So what constitutes – we'll start with what constitutes the UL fire rated assembly. Next slide.

So this is an example of a UL listed fire rated assembly, and the bold text here shows us that these types of assemblies have been actually fire tested. They've been listed by Underwriters Laboratory (UL). They meet the requirements of the 2006 International Building Code, or a specific code that they might have been tested for, and they've been listed in other ways, as well. So a lot goes into the design and construction of these assemblies. But what we're I think going to be showing is that as they actually get implemented out in the field, things get – the interpretation of what constitutes the assembly changes a little bit, and how we actually execute the assembly changes. And so we want to ultimately give you some best practices on how to air seal them. Next slide.

Again, as an example of assemblies, this particular assembly is pointing out that they're using one-inch-thick DensGlass. They're 24-inch-wide panels, Paperless DensGlass Shaftliner panels using H-clips and C-track. And two-inch aluminum breakaway clips. So the assembly in these listings gets defined pretty specifically. But what we ultimately need to decide upon is a common understanding of what actually is the fire separation part, and what is other things that are supporting the wall, but not necessarily the listed fire separation portion. Next slide.

This is just some examples of other UL listed assemblies. So and really what we'll be focusing on today is the Shaftliner type assembly. Next slide. So this assembly is asking us to separate unit from unit, and then ultimately if a fire was to start in one unit, we're trying to ensure that that fire would not spread across the assembly to the other side. We want one side of the assembly to be able to burn completely down to the ground, without that fire moving across the assembly, as shown – and this is depicted in the bottom diagram there. The unit would have burnt completely to the ground without the fire moving across that assembly. Next slide.

So the question is – what are we asking the assembly actually to do? From a sound perspective. Next. So we've talked a little bit about what an assembly is doing from a fire perspective, keeping the fire from moving across the assembly. From a sound perspective, in 1961, this STC rating was introduced as a method for comparing sound transmission through various building assemblies. So sound has become an important component of what these walls are being asked to do, so that we get limited sound transmission from one living dwelling unit to another adjacent living dwelling unit. Next slide.

So we're asking these assemblies to do kind of two things. From a thermal perspective, well, from a fire perspective, we're trying to keep the fire from moving across the assembly. From a thermal perspective, we have an assumption that what we call an adiabatic wall, that there's no delta-T difference, there's no temperature difference across that assembly, so in theory energy isn't moving across that assembly. And then from a sound perspective, we're trying to ensure that the wall is able to dampen any sound that might be moving across that assembly. So these assemblies are quite complex. And we're trying to ensure a number of different things aren't happening across it. Next slide.

One of the things that we're seeing, though, is that we're also being asked to insulate these assemblies. And the insulation is really from two of the three things that we're asking the wall to do. So really from a sound perspective that thermal insulation is trying to help resist the flow of sound from one side to the other side, so that we can achieve that STC rating for the assembly. From a thermal perspective, it's in theory again is not as important, because our assumption is that there's no heat loss across that assembly, because the temperature on either side of the assembly is equal. However, we'll see here in a few minutes that there's a lot of air moving through that assembly, so I think the insulation is actually working to some extent from a heat loss perspective.

But what we're seeing is that also the insulation needs to be installed in the same manner to resist the sound transmission as to resist the flow of energy across that assembly. And we have three primary ways to kind of quantify how well that insulation has been installed. We have the International Code Council, through the ICC, IECC. We have NAIMA, and we have RESNET, all who have given us specific standards for how to install installation. Next slide, please.

If we were to dig into these different standards, we'll see that all of the standards really are looking for the same thing. The IECC really only says with regards to insulation installation is that it needs to be installed according to manufactured instructions. The RESNET standard, especially for grade one standards – so I think really to be code compliant you have to be RESNET grade one if you're using that standard to quantify how well the insulation has been installed. Because the first thing that that standard says is that it needs to be installed according to manufactured instructions.

The next thing the RESNET standard does is pull out some of those key points in the manufactured instructions, and then it gives us a way of quantifying it so that when we're assessing the wall, we can assess if it's been installed according to those manufactured instructions as well. NAIMA does the same thing. It really helps define what those industry manufactured installation instructions are, and then they also have a specific standard or guide for the specifications for fiberglass acoustical installation for the – to help dampen the sound movement across a wall assembly. And if you look at the details in there, you'll see that some of the installation details are exactly the same as what are called out in the RESNET standard grade one, and the IECC insulation and air barrier table that's a mandatory part of that table.

So what we just wanted to point out is that insulation installation inside the area separation wall is as equally important that the quality of that installation happen – is equally as important in that wall assembly as it is in the true exterior building envelope of these homes. Next slide, please.

When it comes down to that installation, we just want to quickly understand how insulation actually performs. It's the ability of that insulation material to trap a pocket of air, and it's that stagnate pocket of air that gives us that rated R-value, which gives us the resistance to the flow of energy, and also gives us a resistance to the flow of sound across that assembly. Also, we want to make sure that that stagnate pocket of air remains stagnant, so we have to have an air barrier.

So it turns out that insulation works exactly the same way as insulation works that we're putting on our bodies. So the woman on the left here has a fleece jacket on. The fleece jacket is trapping pockets of air. But if air – if she walks out on a windy day, those pockets of air are moving out of her fleece jacket. So on the picture on the right, she's put a nylon shell or air barrier over the fibrous material that's trapping pockets of air. And you're able to keep that stagnate pocket of air in the insulation, and you're able to resist the flow of energy. You're able, from an area separation wall perspective, to resist the flow of sound as well.

So what we see here is that just like in our building assemblies, we need to have insulation installed properly that is enclosed in an air barrier system in order to trap that pocket of air to meet the goals of that area separation wall, which is to resist the flow of energy, and sound. And so let's move onto the next slide. And we'll talk a little bit about fire. So let's go to the next slide and ask what's this assembly looking to do here?

So this assembly, the third thing that this assembly is being asked to do is to stop the spread of flame. And flame spread is described, and is used to describe, the surface burning characteristics of a building material, and is one of the most tested fire performance properties of this material. And there's a rating system to be able to do this test. Next slide, please.

So these assemblies are actually constructed, and then burnt to the ground. And we're trying to define the protection against fire penetrating a wall, floor, or roof, whether directly or through a high rated heat transfer that might cause the combustible materials to be ignited on the other side of the wall, or the floor, away from the actual fire. So when we're starting to define the true fire rating characteristics of the assembly, we start to understand that it's not necessarily the whole assembly from interior dry wall, framing that might be supporting that, and then the Shaftliner assembly in there, but that on the contrary it's really just that two layers of sheetrock that's separating the two units. And trying to ensure that those – that that two layers of sheetrock maintain the fire separation for a prescribed period of time. Next slide, please.

So the ANSI standard is one way of doing that. The rating of assemblies are determined by actual fire tests. So they're building these walls, then they're measuring how long it takes a fire to move from one side of the assembly, where the fire has been started, across that assembly. And we get our actual fire rating by ensuring that it takes longer than two hours, or, if it's a one hour assembly, longer than one hour. But in the picture here we see framing. We might see some clips. The object of all those things is to ultimately burn down and fall to the ground, while leaving the true fire barrier intact and standing and keeping that fire from moving from one side of the assembly to the other. Next.

So from an energy perspective, what are we asking the assembly to do? Next slide, please. So the code that got people's attention with regard to the energy side of the equation was the 2012 IECC. The 2012 IECC, next slide, please, is asking us to air test these assemblies. And we see here that in climate zones one and two, these assemblies, just like a single-family homes, townhouses, duplexes, that are utilizing these area separation walls that we're describing today, would have to be at five air changes per hour, in climate zones one and two, and achieve three air changes per hour in climate zones three and four. Next slide, please.

What we're seeing in the field is that single-family homes aren't having difficulty achieving that air leakage requirement. But multifamily homes that are using these area separation walls are having a difficult time meeting these air leakage requirements of the code. Largely because this area separation wall, this Shaftliner assembly, has a gap that runs continuously from the foundation up the front of the building, across the attic, and down the back side of the building. And that one inch gap is often open to the attic, and to the outside, at the front and the back of the building.

So from an energy perspective, we are realizing more and more that a significant amount of energy is moving with air, so that assembly is impacting the energy performance, and comfort, of these units that are built with area separation walls. So we need to dig into these assemblies a little bit more, and see how we can address that air gap specifically. Next slide.

So what these assemblies are asking for is some type of fire blocking that needs to be installed on both sides of the area separation wall. And potentially at each floor level as well. This particular UL design tells us that there's a number of different things that can be used for that fire blocking. The bold section here says we can use two inches of nominal lumber, we can use a gypsum board, including one inch DensGlass, and we could use batt or blanket or mineral wool or fiberglass in those assemblies. So from our experience we're seeing that there are certain materials that are fire block materials, but are also air barrier materials, or they – obviously they resist the flow of air across that material.

So we're looking – what we're understanding more and more is that just like in other areas of our home, where we're looking for materials to block holes, we want to make sure that that material is a true air barrier, and not permeable to the flow of air through it. So it begins out understanding that we need to in essence stop using draft blocking materials that are air permeable, and we need to move to using fire blocking materials that are air impermeable. So away from fiberglass blankets or mineral wool type material, and to nominal lumber and DensGlass materials, or one inch drywall type materials that are allowed.

So the ultimate thing that we want to point out is that there's choice here, and a number of jurisdictions and a number of builders have not always recognized those different choices here. So you might have to take them back to the actual listing of the assembly to ensure that they understand that these – there are choices that you can make for the material that you put in this particular gap between the true fire assembly, which is the two layers of sheetrock, and the framing that's helping to support that on either side of the assembly. Next slide, please.

So this is an example of utilizing that material differently. So moving away, in essence, to the pictured, in this case, fiberglass draft blocking material, to an actual rigid material. Some of the things that you have to consider are how you're going to maintain the clip in this assembly. So if we're looking at the large picture on the right here, we see the wood framing that's supporting the fire rated assembly. And we see a clip there that is attached from the framing to the actual fire rated assembly. And then a piece of one inch sheet rock, a true air impermeable material that is filling that gap there.

Now, the whole object of the framing and the clip is that they will, if a fire is started, they will burn and separate from the wall, so that the unit collapses in on itself before the fire is able to penetrate the wall to the adjacent unit on the side. That has not been compromised by putting a one-inch piece of rigid material into that gap there, as long as you do the clip connection correctly. As you can see here, there's still some gaps there that need to – that really should be air sealed. But we have a gap that is of a reasonable size, and typical air sealing materials can be used on that. Or, we're recommending that they be used on it. That's ultimately going to be our question as we get to the end here.

What we're finding is that if you're standing in the middle of a unit, and you're looking at the area separation wall, in essence you want to picture frame that wall. So you want to put a piece of this one inch sheetrock, if we're standing on the second floor of a unit for example, you want to put it to the attic in that gap. You want to put it to the front and back walls of that assembly. But you also want to put it between floor systems, which the lower right hand picture is trying to get at. And ideally you want it to hang over the top and bottom of that floor system a little bit, so you have actually something to seal against there. In that way, we're separating floor from floor, and we're also getting material in there that actually stops the flow of air there. Next slide, please.

We also have to remember that the requirement of these assemblies is to carry that two layers of sheet rock that's your true fire barrier from foundation all the way to the roof deck. And that means that there's some elements at the foundation connection that are adjacent to that one inch gap where air is moving. So it's also really important to tackle the air sealing that's happening at the rim joists if your foundation type is a basement or a crawlspace, or potentially your bottom plate, to a slab connection. But these pictures are demonstrating that anchor bolts need to be sealed, that the rim joists or the sill plate needs to be sealed to the foundation, the rim board needs to be sealed to the sill plate, and the rim board needs to be sealed to the subfloor, because there's a direct connection to that one inch gap where air is moving in that – behind that assembly there. Next slide, please.

So this just gets at that detail in a little bit more depth, making sure that we again are sealing the sill plate to the foundation, because our sill seal is again primarily a capillary break, and often there are gaps between the sill plate and foundation. And then you'll always see gaps between the rim board and the sill plate, and the rim board and the sill floor. So in order to tighten these assemblies well enough to meet our air leakage goals from a code requirement perspective, these details need to be addressed. Next slide, please.

Now, when we're seeing these area separation walls built with crawlspaces or basement crawl combination foundations, we also see that there's connections between unit to unit in those crawlspaces, based on how well those crawlspaces are backfilled, and how well the vapor barrier, air barrier, is installed over that dirt. The picture on the left is showing that there's a direct connection from crawlspace to crawlspace, and unit to unit. Because the back fill wasn't done well enough.

In the picture on the right, it's showing that during a depressurization test with the blower door, we're pulling air from the adjacent unit, and it's blowing up my vapor barrier and air barrier over the dirt of the crawlspace, because I'm pulling that air underneath that area separation wall foundation, from one unit to another unit. So we need to make sure that we get a good back fill, and that we install those vapor barrier air barriers over the dirt very well, because leakage comes through the soil as well, from unit to unit. Next slide, please.

Another area that we're seeing that is very difficult to air seal – are when we have tuck under garages that are associated with these area separation walls, and stair systems that are going up adjacent to that area separation wall. So attention to detail here is crucial to not only get a continuous air barrier past the stairway, but that we potentially do some additional air sealing between our garages and our living spaces above. And the floor systems that are separating that. So, again, utilizing that one inch sheetrock, and spanning it from just below the floor system to just above the floor system in these locations, can help ensure that we're getting great separation of air that's moving potentially moving in those assemblies, or moving from outside to inside, through these connections between garages and houses. Next slide, please.

Just some additional pictures here to show the complexity of these assemblies. Making sure that they get insulated properly. But also again that they get separated from an air perspective, well between these assemblies, that are trying to separate house from garage, stairway from garage, and house from area separation wall. And garage from area separation wall, really. thank-you.

The air leakage and air barrier table that's located in the International Energy Conservation Code is a mandatory table. We want to ensure that people know or understand that this table is a very good guide for how to create an airtight home. And for single-family homes, if you follow this table very well, our experience has been that there's no problem at all meeting the air tightness requirements of three air changes or five air changes, depending on your climate zone. For multifamily, and townhouses, and duplexes, this table still needs to be followed with some additional details or additional thought process going into properly air sealing the area separation wall. Next slide, please.

But what we really wanted to point out is that we need to complete air sealing or smaller gaps and seams that cannot be addressed by solid blocking. We need to utilize – we need to ensure that that table is being utilized in these multifamily units, but that we probably need to address the smaller gaps that we've created in that area separation wall. So we've put drywall into that gap, and we've taken away a large gap, but we still have small gaps there that need to be addressed. And these details are not necessarily addressed right now in the UL assembly, in the listings that are noted in what's called the BXUV guide. And Ari, in a moment, will be going into that in much more detail.

The other problem we see are many jurisdictions do not allow air sealing of these small gaps and these seams, and so we want to make sure that everybody understands that you need to begin a dialogue with your specific code jurisdiction to begin to understand what they will allow, what they won't allow, how they actually define that area separation wall. Is it just the two layers of sheetrock that is the true fire separation, or are there other things that they believe creates that assembly?

And you might have to go back to the actual UL listing of the assembly to demonstrate that you can use other materials than fiberglass or mineral wool to block those gaps, and then next slide please, that you might have – that you might have to talk to them about ensuring that you are following the air sealing table that's in the code against these area separation walls. So what we like to do in the field is treat the common wall just like any other exterior wall.

So if you have a fireplace against that wall, if you have a tub against that wall, if you have a dropped ceiling against that wall, if you're using the code air barrier and insulation table, you just want to make sure you're using it consistently on your exterior walls and your area separation walls to make sure you have a continuity of that interior air barrier system inside the house, that you get that air barrier behind the tub, behind the fireplace. Especially on those exterior walls, but in addition to that area separation wall, because air is moving in that assembly, and we need to control it at that level, and then what we're ultimately talking about is actually controlling it inside the area separation wall as well, by utilizing that one-inch piece of sheetrock. Next slide, please.

So what we want to see is that the mineral wool fiberglass draft stopping is replaced with a true fire blocking material. What that does is it lessens or makes that gap smaller there, and it gives us the opportunity to seal successfully a smaller gap. And our ultimate question is – will code jurisdictions allow us to seal that smaller gap with traditional air sealing materials like a foam gun material there? Next slide, please.

So we now have that smaller gap. And you can see the picture on the right, and on the lower left, for example, that this builder was allowed to seal that smaller gap with a traditional hand foam gun, like a Hilti foam gun for example, to be able to make that area separation wall much more airtight. Now, the ultimate issue we have is that we need to create that dialogue with the code official, way back before submittal of these assemblies, and these projects, to ensure that the coder jurisdiction will allow us to do this type of sealing. We're trying to give people the tools that they need to be able to allow this type of air sealing, and that's what Ari will be touching on here in a second. But this is the ultimate recommendation for how to air seal this. Next slide please.

So what other alternatives are out there? The first thing to think about is what the code will allow. Remember, they'll allow replacing fire stock materials, like fiberglass and mineral wool with fire blocking materials like two by four or actually framing materials, or that one inch DensGlass or drywall type material. Some jurisdictions will allow you to do different things in the wall assembly, like using foams and that, or insulating it completely full. Or some jurisdictions have modified the code allowances there. And then ultimately alternative area separation wall assemblies. So next slide, please.

So this is an example of some alternative materials. This is generally thought of as jurisdiction by jurisdiction approval that's needed for this alternative material. But in this case, instead of using one inch of sheetrock, they filled that one inch hole or gap with foam. And again, some jurisdictions will allow that, and some jurisdictions won't allow that, but the big takeaway here is start the dialogue with the jurisdiction as soon as possible, so you can start identifying what they'll allow, what they won't allow, and or you can start building your case why you want to use this method instead of another method for sealing that assembly. Because ultimately you have to do all of this preplanning to be successful at meeting that air leakage requirement that's in the code right now. Next slide, please.

So we know that the code is asking us to test these assemblies. And some jurisdictions, like Denver for example, have actually amended their code to allow a different level of air leakage. So Denver for example for attached dwellings, is allowing an air leakage rate of four air changes per hour, instead of three air changes per hour, in our climate zone five here in Denver. That's good. And it makes it a little easier to achieve that. But the reality is you still need to work hard and plan well and understand what the jurisdiction will allow and now allow you to do, even to reach this level of air leakage, when you're talking about multifamily homes that are using Shaftliner area separation wall assemblies. Next slide, please.

New York State is another example of a statewide code in this case that has changed the matrix from an air leakage air changes per hour matrix to a CFM per square foot matrix, in that you can use or are required to use in New York State, to measure the air leakage of multifamily housing. Now, this particular matrix is even more beneficial for stacked multifamily units, where you have area separation floors, systems to above and below a unit, and area separation walls from unit to unit. Because you're able to take into account not only the leakage that is happening from directly outside to inside that unit, but from unit to unit as well.

So we're getting into what's called compartmentalization, and I don't want to go too far into this. But it is an interesting matrix to start thinking about. And if you have an ability to impact how this is being adopted in your particular jurisdiction, this might be a really interesting matrix to think about for your particular jurisdiction. Next slide, please.

Fort Collins is another jurisdiction that has – Fort Collins is in Colorado. That have looked at different matrixes that demonstrate compliance with the air tightness requirements of code, and they've gone a little bit different step here, in that they're defining air leakage for specific housing types. And they're looking at single family houses. They're looking at single family attached houses like duplexes and townhouses. Versus multifamily houses. And they've also gone into air testing and air leakage testing for commercial buildings.

So these are just three examples of what jurisdictions are doing around the country. And it's really important again to understand what your particular jurisdiction is looking for, and how you're going to plan to be successful in that particular jurisdiction, because especially with multifamily, it takes significant planning upfront to be successful at the end. And because blower door testing or air leakage testing happens at the end, you don't want to be caught off guard at that end process there. Next slide, please.

Other things to think about are different alternative area separation walls. So in this case, they've put drywall air barriers on both sides of the assembly so that your air gap is actually separated between the two units there. So it's another way of thinking about it. I think the area separation walls or the Shaftliner area separation wall – a lot of people believe is the most economical system. And that's why it's probably the most widely used system. But we just wanted to show you that there are other alternative area separation wall assemblies there that might be doing a better job at actually separating that air gap from the units themselves. Next slide, please.

This particular area separation wall puts two layers of sheetrock on either side of the assembly. Again, giving you a continuous air barrier. There's little to no air leakage from unit to unit. And there's no direct connection to the outside or to the attics in this type of assembly. Next slide, please.

This one and the next example are kind of doing the same thing. They're getting – there are alternative paths to getting rid of that air gap that's connected to attics and outside, by filling the assembly completely full of insulation. In this case, it's a mineral fiber. Next slide, please. And the next slide here is showing very similar assembly, but it's a cellulose type assembly. So again, it's doing some research, figuring out what assembly is going to be best for your particular application, what you're designing for, but making sure that you take in the air leakage side, the energy side that these assemblies impact on the home, as well as the sound and the fire side of the assembly. Next slide, please.

Just another example of an alternative area separation wall. Next slide, please. So now I'd like to pass off to Ari, who will be taking us into our next steps.

Ari Rapport:
Thanks, Robby. So what I'd like to do is give everybody a little information about work that has been done in collaboration with the DOE through Building America to address fundamentally the issue that Robby has been discussing, which is air sealing of these fire rated area separation walls. Specifically to make it really clear so that any code jurisdiction, any code official, has a mechanism by which they can point to approved methods of air sealing these walls that can address not just what's already allowed, which is the use of the solid blocking material, but also air sealing some of those smaller gaps and seams and things like that in the wall system. So, next slide.

And this is just a kind of recap, but I'm going to get a little bit more – pinpoint a little more of the issue related to code. Robby's done a really good job of presenting for us that there's an energy impact to the way many of these area separation wall assemblies are currently being constructed, where air movement from outside to inside the dwelling unit can have an energy impact, and ultimately is a quality issue when it comes to construction. Not being able to get that assembly built according to what we understand are the best practices.

So how this is sort of the circuitous route in many ways that ties to the code is – or may be straightforward, I should say – is that right now these fire rated area separation wall assemblies are being tested and listed by UL, according to their standards and test protocols. And most of these assemblies do, as Robby indicated, allow for some of the solid blocking material. But there's no – for the most part, there's no explicit verbiage, language, in these UL listed assemblies that allows for – makes it okay to use – other air sealing methods, such as foams or caulks. And, as a result, what we're finding is when code officials are asked to make an assessment of whether or not those foams or caulks could be used, the result is that some of them will default to, hey, it's not listed in the UL listed assembly.

Therefore I'm not comfortable allowing it. And there – that's completely justified. The impact of that, however, is that air sealing isn't done as completely as it could be. So that makes it difficult, both to achieve the performance, the energy efficiency quality performance of properly air sealing those walls according to industry best practices, but also makes it really difficult for builders to meet those air tightness targets that are currently in the 2012 IECC, which is in the climate zones three through eight, three air changes per hour, tested at 50 Pascal.

So there's kind of a conflict, where the code requires the use of the UL listed area separation wall assemblies, but then the code also requires that air tightness limits of 3ACH50 are met, which is really difficult without air sealing, using these materials. Which are not specifically indicated as optional air sealing or allowable air sealing in the UL listed assemblies. Next slide.

And this issue is not new. This is an ongoing issue that builders, that code officials, that building scientists, the DOE, others, have been dealing with for a number of years. And even before the 2012 code hit, we recognized that achieving tighter air tightness limits in these attached single family attached dwellings is really difficult without being able to properly air seal them. So, again, in collaboration with DOE, through Building America, IBACOS and others pulled together an expert meeting in 2014. A cross section of the industry was represented at that meeting. We had DOE, we had National Labs, builders were involved, the industry organizations related to _____ and wood and steel and metal, manufacturers were represented. And in that expert meeting, we looked at this issue.

We identified what were the problems we've been talking about today. And then we brainstormed and discussed several routes to resolve this. What are some solutions to this problem? The three solutions that were identified included going back and having all of these UL listed area separation wall assemblies retested. That is certainly an option that could be pursued by any manufacturer or sponsor of a UL listed design. However, it was recognized that that was probably the most expensive route to go, to go through full retesting.

We also explored, well, UL has an online guide. Their BXUV guide. And in that guide, which addresses, among other things, the fire separation assemblies, they do have notes, and in those notes, they kind of provide some additional information and language that can be used to help code officials interpret the best practice of installing these fire rated assemblies. So if we can have UL revise their BXUV guide notes to acknowledge and allow for some of these additional air sealing practices, that could be a more cost effective way to provide a mechanism for the industry to start doing this air sealing.

And then the third possible solution that we explored was going through the code change process, where we explicitly require the use or allow for the use of these sealants. And we recognize that's still a viable option, it's just a much longer term option potentially, and can still be pursued in parallel. So the results of this expert meeting are available through DOE. There's a report that was done to capture the information that was discussed. The background and then the possible solutions. Next slide.

So, as I indicated, the current effort, again, this is an effort that is being funded in part by DOE through Building America, is to allow for and ultimately going back to that slide before – the solution that we agreed on as the immediate course of action was engaging with UL around revising their BXUV guide notes to allow for these air sealing practices. So the current effort right now is really that. Is engaging with UL, providing them with what we recommend as the methods of air sealing these walls that would provide a best practice result from a performance and from enabling the code compliance with the energy code. For UL to evaluate those potential solutions, and to, if they approve those, to revise the language on their online BXUV guide notes to allow for that effort. Next slide.

In addition to asking UL to evaluate these potential air sealing methods, and then to revise their online BXUV guide notes, we're asking that they offer as guidance to the industry a guidance document on their online technical library. Their technical library has a number of different – call them two pagers – that provide some quick reference information for code officials, for field installers, to utilize their different listed assemblies. Next slide.

Not going to go into much detail here, but essentially there's a number of different potential solutions to provide the needed air sealing that we are providing to UL for them to evaluate, and potentially offer as options to address air sealing related to the fire rated area separation wall assemblies. Next slide.

This is a link to the BXUV guide notes. You'll see on the left there's an image that's a little bit blurry, but there's a table of contents at the time, which are the categories of fire rated assemblies where the notes are offered as additional information. Number six in that list is walls and partitions, which is what we're talking about with these fire rated area separation wall assemblies. That's where we're asking UL to make their language revisions after completing their evaluation of potential air sealing methods. Next slide.

And then as I indicated, we're asking them to offer guidance on their online technical library. Here's a link to the technical library. There's a list of current two pager guidance documents that they have available. And once revision language through the BXUV guide is issued, guide notes, there would be a guidance document available on their library. Next slide.

So what are our immediate needs with this current effort to engage with UL, and work with them to revise the notes that would allow for additional air sealing of area separation walls? Well, we want to continue our engagement with stakeholders. There are a number of different organizations, companies, and others who are affected by this issue. So if we want to continue engagement with these stakeholders, and ultimately to collect funding to UL, under this work with DOE, DOE understands and is willing to enable and facilitate this effort, to resolve this issue.

What they recognize as an industry effort is actually the revisions that UL would be completing and making available in their online BXUV guide notes. Therefore, in order to fund UL for their effort, we do need to engage with industry to collect the needed payment to UL. So that's one of our primary efforts. Our goal is to have funding available, and initiate an agreement with UL, by the end of January of 2017, next year, so that's in about a month and a half. At that point, UL will begin their evaluation, and at some point within six to eight weeks, will enable – will issue their assessment, their results, and if successful, if they agree with the proposed solutions, they will then provide the language revisions onto their online BXUV guide.

So we're hoping that that would be complete by the end of April. And then they would make their technical guidance document on their online technical library by midyear. So that's our timeline. That's our goal. That's what we're looking to do. Certainly willing and interested to get any input and engagement from any stakeholders out there, anyone on this webinar, others to resolve this issue, or help resolve this issue. Next slide.

So, with that, Pam is going to provide for you guys some information on available resources through DOE.

Pam Cole:
Thanks, Ari. The screenshot that's up is Building America's solution center. This is getting to be a pretty much widely used resource for builders, architects, and code officials. And within the solution center, there are different mechanisms and areas you can go. Over on the left-hand side of the screenshot is there are building components. So you can go in, in different mechanisms, at looking and searching for materials through building components. What I have up on the screen is I have searched on the guides. There are hundreds of guides within the solution center.

And I've chosen for today's webinar air sealing multifamily party walls. As the example. There's home ENERGY STAR Certified Homes information on ENERGY STAR. There's also a lot of information on zero energy ready homes, EPA indoor airPLUS. And then there's additional resources. There's a sales tool. I won't get into a lot of these, but there is a tutorial within the solution center that can take you through. Explain some of these. There's a mechanism to ask questions if you have questions with the content that's in within the solution center.

There's hundreds of CAD files. Shows you some of the today. There's additional ones also in this library. There's an image gallery that shows a wrong and right way on different techniques and solutions. Some are air sealing, some are other framing, and so forth. There are also videos, climate specific solutions. And then there's code briefs. So what I'm focusing on really is the code briefs. Code briefs were just developed this last year, and beginning of the year before. There's approximately over 30 briefs that are in there. And the reason of the code briefs is when there is a barrier that we're aware of, maybe it's through some Building America research that's going on, or something that they have come across in the field, and it's providing additional information and solutions of how to overcome that barrier.

Since there was one on multifamily party walls, this code brief was developed. There's two ways to get to code briefs in the solutions center. On the left-hand pane, you can go right directly to the listing of all the code briefs. Or you can, within a guide, if the guide has a code compliance brief, which the multifamily does have one, the tabs across the top are all the other pieces of information and content within every specific guide. And within those there's a tab called compliance. And then in the upper right hand side, if it has a code compliance link, or a code compliance brief, it will take you to this additional information on the brief that'll show you an example of.

And again I'll touch just one more before we go to the next slide is the other content that's within the guise of the solution center is there's a scope that explains the actual details of the topic at hand. This one being on multifamily party walls. A description. Success. If there's a success story, of how to do this new technology, or solution, better. There's climate information. There's training. Might take you to some additional links outside the solutions center on available training. There are CAD drawings that might be available on this topic. Compliance goes into under this tab. It'll start out with ENERGY STAR certified home specifications, if there is any.

It will then go into any requirements that may be applicable for common walls for your DOE Zero Energy Ready Homes, and then it takes you into the actually IECC and IRC just high level specific provisions. The code brief provide a lot more detailed information. You can go to the next slide.

This is just the other way of how you can get to the code briefs. Another screenshot. If I was to click on the left-hand side of the solution center, where it had the menu item code briefs, it would then take you to this screen where it lists out all the code briefs available. You can also search on them and other information in the solution center on the right hand side. So you can filter by topic. You can filter by keywords. Or you can even filter by climate zone. And you can go to the next slide.

So these code compliance briefs, just very high level, what are they, and why are we creating these? This is an effort through Building America, when a need was developed, so that we have identified that there's some additional guidance that was needed on it could be a technology or solution now becomes available, to move something through, an innovation, to get that thing through market. And these barriers on how we look at them is well, does the code require something wrong? Or is this technology prohibited by code? Or maybe discouraged by a code or standard? Or, in a lot of the cases, it's not really encouraged or discouraged, it's just not recognized at all. And that's typically a lot of the cases when it comes to a lot of these briefs that are in the solution center. You can go to the next slide.

So the intent of them is really to take a lot of the information that Building America has, and some of them are really detailed research reports that might be over 100 pages long, where a code official just doesn't have that time to go through a 100 page report to determine if a certain technology or certain provision that maybe a builder has in his plans if he'll accept it, for compliance. Maybe a plan review, or maybe during a final inspection. So what how it is broken down is they all are basically the same.

They have an upfront description of what the specific item is. Then it will go into the actual sections for plan review. And sections for field inspection. And then the last section of these briefs provides that technical validation, which will give you the links to any more detailed reports, maybe more detailed drawings, but really what it's done is it's just kind of shrugged down a specific topic that has a barrier or could possibly be a barrier, and providing that additional information that's easy to get to, that puts the solution on the same playing field for the builder and the code official.

So both of them can be looking at these code briefs and going, okay, I understand it. Here are all the code sections involved. Going to take you out to where the codes are. And it's more of a discussion for you can discuss the solution together, and hopefully get that technology through, so plan review gets approved, and final inspection is done. You can go to the next slide.

So with that, the resources here – here's the screenshot of the actual code compliance brief for air sealing the common walls. And this is just the first page. There's several pages to this brief. There's a lot of different code sections, as Robby got into. There are a lot of different code requirements. You get into fire ratings, you get into sound and so forth. But there's also in here air sealing techniques and air sealing and the provisions that's in the code. And then lastly alternative materials and methods, which is allowed by code. And those solutions that will help you get there. For the main reason, for multifamily, is meeting those air leakage rates that are in climate zones three through eight, at 3ACH50.

This is another example of this code brief is quite popular. The city of Colorado, the state of Colorado, has taken this brief and provided it to several code officials throughout the state, because this is one of the topics that they receive almost about 100 questions a month on. We know there's issues with testing these buildings, so we're trying to provide the resources, and then the education and outreach, to try and overcome this barrier. And that's really the intent of a lot of these code briefs, is providing that additional information to help provide the education and outreach to get these different solutions and technologies out in the marketplace. You can go to the next slide.

This is just a screenshot of the solution center itself. Because there is quite a bit of content, not just the code briefs, but provides an interface for if I'm a code official or a builder, I can basically log in and start creating field kits. And maybe I just want code briefs, or I'm out in the field, and I want to take a look at a certain picture on how provisions should be done, or insulated properly, or the framing of a certain way of framing technique, advanced framing, or so forth. I can start creating my own field kit that I might be able to take out in the field.

So there's this tool is embedded within the solution center, and there's a way to log in and start capturing just the content that you maybe want to have on your laptop or your iPad, and take that with you. So it's just another easy simple interface that can be used as part of the solution center. Next slide.

And I'm going to end with I want to give some acknowledgements and thank-you to the Building America Program for allowing us to provide this information today. And that would be Eric Werling who oversees the Building America Program, and also the Energy Codes Program – David Cohan and Jeremy Williams – because we've collaborated this effort on this webinar to provide the continuing education credits, and more or less provide information that is tied to codes, and is tied to a lot of different codes, but it's also tied to the energy codes, and more than that's what the Building Energy Codes Program works on, is the national energy codes, so I'd like to thank them as well.

The last thing on this slide is if you want continuing education credit, and you are an architect, and you want learning units, take down that URL, and you will want to either cut and paste that into your browser or type that URL in and submit your name and request a certificate of attendance or provide your AIA information and we will get those out to you within a week or so. And I would like to appreciate Ari and Robby for taking the time to go over all the details of what is going on with common walls and energy separation walls and air sealing. And thank-you for attending today. And I'm going to turn it back over to Linh.

Linh Truong:
Great. thank-you so much. Thanks Pam, Robby, and Ari, today. As we go into our Q&A session, I just wanted to remind everyone that you can find information like upcoming webinars and information like that on our Building America website. So you can go to the URL there. We've already had some questions about this, but wanted to make sure that as I mentioned before, future webinars, you can go to this specific website on the Building America site, and also subscribe to the newsletter, which goes out the second Thursday of every month, and you can get the latest information about webinars, publications, and other resources, published through the Building America program.

So to answer a few questions, the presentation today is being recorded, and so the presentation slides will be posted later this week, and then the audio recording will be posted within a few weeks after today. So with that, I'm going to go into the Q&A session. And I'm going to try to put a timestamp on this to help the speakers in terms of when the questions came in, but Robby, at the very beginning –

Pam Cole:
Linh, before we begin, could you put up the slide where it has the link to the – for them to go out and get their certificates of attendance?

Linh Truong:
Yeah, I will leave it on that slide. Here?

Pam Cole:
Yes, perfect, thank-you.

Linh Truong:
So, yeah. If you didn't get a chance to jot that down, jot that down as we're in our Q&A session in the next few minutes before we wrap up. We'll go through as many questions as we can. And if not we'll reach out to you afterwards. Robby, I'm going to throw the first question to you. And it's about when you were talking about the fire blocking. But it's talking about the delta-T and the impact of the delta – I'm sorry, the delta-T. So if the adjoining unit is not occupied and unheated, will you have a delta-T, and what is the impact of this?

Robby Schwarz:
You might have a delta-T. The primary problem is that from an energy analysis perspective, that area separation wall is defined as an adiabatic wall, which makes the assumption in any type of energy modeling that you're doing ,that there's no heat loss across the assembly, because the temperature is the same. That assumption is not always the reality. So obviously energy moves from high to low, or from more to less, so you're going to – you will have some heat loss if that's not the case. And one of the things that we know right now is that air is moving in those assemblies. So even before it gets to the – even before you take account on the other side of the fire separation part of that assembly, you have a different temperature there. So the insulation again needs to be installed well. Not just from a sound perspective, but from an energy perspective.

Linh Truong:
Okay, Robby. In this same section also, someone was asking about fire blocking foam, and what your thoughts are about that as an option?

Robby Schwarz:
I think fire blocking foam can work, and work well. I think that the number one takeaway is that the devil is in the details. We've seen all kinds of different techniques being used, and it's really the main issue is how well it's installed, to how well it's going to perform. So we have seen a project that used fire-rated foam. And to be honest, it still didn't pass the air leakage requirements of code. So and we've seen other assemblies installed in other ways, and they've passed, and some have passed, and some haven't passed. So to me it's really the devil is in the details, how well it's actually been installed.

Linh Truong:
Great, thank-you, Robby. And with this next question you did actually touch on this. So if you want to repeat and expand, please do so. But the specific question is – are you allowed to use typical air sealing materials, like caulk and foam, to seal the gap between a fire block gypsum and a wood frame?

Robby Schwarz:
So that's the focus of what Ari was talking about. Right now, the UL listing is silent on the issue. But UL verbally has said you're allowed to. So it's really a question of talking to the jurisdiction and doing that pre-planning and making sure that the jurisdiction will allow it. In Colorado most of the jurisdictions are allowing it. And Ari's effort is to get it in a written format so you can, in essence, take it to the code official, and demonstrate that it's actually allowed. So hopefully that answers that. Ari you might want to jump in there.

Linh Truong:
Ari, would you like to add to that?

Ari Rapport:
I'd just echo what Robby said. UL has indicated that verbally that these methods of air sealing the gap using foams or caulks should be acceptable. They want to complete an engineering evaluation of those practices. But seem to be in favor of them. The goal would be to get that agreement in document, or get that language in documented form, in written form, so that anyone can refer to it, and it can be used to support that kind of air sealing.

Linh Truong:
Great. thank-you. The next question, and any of the speakers can jump in on this one, but for the example for which have been permitted to use foam in some jurisdictions, do the AHJ require specific ratings for the foam?

Robby Schwarz:
What we've seen is that the jurisdiction having authority is basically saying yes or no you can use this. And they would want yes, they would want – I can't say they've asked for a specific fire rating certificate. But they have asked for some documentation that the material is a fire rated material.

Linh Truong:
Okay, great, thank-you. So the next question is – what is the exact purpose of the three-fourths inch air gap in the wall assembly? Is this to allow fire to easily get to the aluminum clip so they melt and allow the structure breakaway? Could you please explain?

Robby Schwarz:
Yes. I mean that's my understanding is that the gap is there specifically for the clip. So that the clip is what's really holding that fire assembly in place. And that whole object is that the clip will melt. And the wood framed wall will burn to the ground before that fire moves across the assembly. So you don't want to attach the framing directly to the fire, the drywall fire assembly. And so the gap is to make sure that you have that space for the clip, and that you're not directly connecting again the framing to the fire assembly.

Linh Truong:
Great. thank-you. And before I go into my next question, I just wanted to flip it to the contact page, upon request. And I will go back to the link for the credit – but there is a request to have the speakers' contact information up. So for the next couple questions, I just want to hold it on this slide. So Pam, the next one is for you. It's in regards to the code briefs that you talked about. In developing the code briefs, is there a review done to assess and integrate any ICC content on the topic which may already have been developed, such as interpretation?

Pam Cole:
There is no interpretations, one, because we're not allowed to do an informal or formal interpretation of any of ICC's code. That is up to them to provide those. You can request an interpretation through ICC, and they actually have a code form on specific codes that you can go into and ask a question or submit one directly through ICC's mechanism. I have been working with ICC. They're aware of these code briefs. I think there's a lot more that can be done with ICC, and I'm working on that.

The first one being is that we are appreciative that the coast program allows us to be able to offer CEUs for these trainings. The next one will be is taking a look at is there more information, and is it possible if there's an interpretation, and it might be that ICC would allow us to add that to that code brief. I think it would be of great value. Because really that code brief is for the code officials and builders to be on the same playing field when there is a certain issue at hand such as this one. What's allowed and what isn't allowed, and what are some of the resources to make sure that you can move this through the process, and there isn't an issue with getting this solution recognized and implemented? So again, that's a great question, though. It's a very great question.

Linh Truong:
thank-you, Pam. I think that we do have some more questions about the fire blocking foam. So, Robby, if [laughs] if you want to repeat or expand feel free to do so. But this question is that as you mentioned, would you even have to use fire blocking foam? Wouldn't regular foam be allowed because of drywall on the inside of the wall?

Robby Schwarz:
I believe that that's what UL will be determining, and I believe that you can, but, again, nothing's in writing, so that's just my personal opinion. So that's our complete goal is to get something in writing, in the guides that UL develops. So that you can move ahead with clear understanding of what's allowed and what's not allowed, and take that to each jurisdiction in your planning process for these assemblies.

Linh Truong:
Great, thank-you. And this next question, any of the speakers are welcome to jump in on this one. Where does building envelope requirement of IECC defined thermal envelope to include part wall interior to a building?

Pam Cole:
Want me to answer that one?

Robby Schwarz:

Pam Cole:
Well, on the residential side of the IECC, there is a definition for building thermal envelope. However, there is not a definition in the IECC for that common wall. Back in the '09, there actually was a provision in the air barrier table on how to air seal common walls. And for some reason, not known, that common wall – just that line item for common walls was taken out. But there is not. I hope I'm getting at the question. And, Ari and Robby, you can expand upon it, then the commercial side, if you go over to the commercial chapter, there's additional details, and, again, it goes into multifamily. But you will not find in the definition for that building thermal envelope where there's – there's really not a discussion on it when it gets into the common wall area.

Robby Schwarz:
I'll just add real quick that this issue was brought up at the last code hearing process. And it didn't successfully go through the code. So we're going to have to go through another three year process to try again. Again, it just brings up the issue of needing to have this dialogue with your particular jurisdiction as soon as you know you're going to be building these types of assemblies, so that you can get these things to find for the particular jurisdiction that you're working in.  

Linh Truong:
Great, thank-you. And I apologize to the audience. We're not going to be able to get through all the questions today. But we'll make sure the speakers are aware of the unanswered questions. I just want to wrap up with one final question for our speakers. Is air sealing at the sheet rock level a good strategy for complying with the ACH requirements?

Robby Schwarz:
I would say that it's part of the strategy, but it can't be the sole strategy. So that's why I was saying that you need to treat your area separation wall just like your exterior walls and get the continuity of that interior drywall air barrier system behind a tub that's adjacent to that wall for example. But you most likely are going to still need to address the gap in the area separation wall to be completely successful. The integration. The synergy of all the air sealing that has to happen to be successful.

Linh Truong:
Great. And thank-you. We have a lot of our participants expressing their thanks through the portal as well. So, thank-you, Pam, thank-you, Robby, and thank-you, Ari, for your time today, and your expertise. And for all of our participants, we appreciate the time you've given us today. If you have any questions after the webinar, please feel free to reach out to us. The email address is And with that, I hope everyone has a wonderful holiday season, and thank-you everyone for your time today.

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