Air-Tightness Testing and Building Codes in Australia with Sean Maxwell

Standard construction (both in America and Australia) is sometimes a “race to the bottom” of who can satisfy the building code at the lowest cost. We know this doesn’t always result in better buildings, so we have to educate the industry and encourage a commitment to quality based on solid science. This is what our guest, Sean Maxwell, devoted his career to after moving to Australia and finding himself underwhelmed by the presence of building science principles in the local codes and standards.

This episode raises a few important questions: How do we improve the quality of construction? How does the effort differ in Australia vs. America? And how does the “carrots and sticks” approach to code enforcement relate to building performance, and is it effective? Listen and start thinking!

Episode Guest: Sean Maxwell, ATTMA Australia & New Zealand

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Sean Maxwell is the Australia and New Zealand Scheme Manager of ATTMA, a global association of building air-tightness-testers. He formerly worked with Steven Winter Associates, Inc. in New York City before moving to Australia in 2015. Now, Sean works with Pro Clima Australia as a Technical Manager. He is also a committee member of Standards Australia, works to improve building codes and standards, and helps regulators and stakeholders see the value in building envelope commissioning through air tightness testing.





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Buildings and Beyond is a production of Steven Winter Associates. We provide energy, green building, and accessibility consulting services to improve the built environment. For more information, visit


Robb Aldrich | Kelly Westby

Production Team

Heather Breslin | Alex Mirabile | Dylan Martello | Jayd Alvarez

Episode Transcript

Kelly (00:05):

Welcome to buildings and beyond

Robb (00:08):

The podcast that explores how we can create a more sustainable built environment

Kelly (00:12):

By focusing on efficiency, accessibility, and health.

Robb (00:17):

I’m Robb Aldrich.

Kelly (00:18):

and I’m Kelly Westby. So Sean Maxwell is a good friend of mine. He used to work for Steven winter associates in the cubicle next to mine, and we would stay up late trying to come up with creative ways to test ventilation systems. Who knew what you could do with a little cardboard, a little tape, and maybe a quick call to Gary Nelson from the energy conservatory. Sean has been in the building science industry for over 15 years and has had a wide variety of roles involving testing building systems, helping building owners, address issues, publishing industry leading research about ventilation and air tightness in multifamily buildings, and training others in the industry. Sadly for the New York city multifamily market, Sean moved to Australia, Australia, mate, Sean explains how finding a job wasn’t as easy as he thought.

Sean (01:09):

When I first got here, I was looking to connect with other testers doing things that I used to do back in New York. So retrocommissioning and testing things, some research in building envelope leakage, and compartmentalization and ventilation, those sorts of really fun subjects. And once I got to Australia, there was just hardly anyone doing it.

Kelly (01:35):

It was tough finding a job, but Sean started doing some air barrier consulting and soon needed to purchase his own blower door.

Sean (01:42):

So I was looking for a quote for a blower door and I got a quote from Thomas Vanremstunk. One of my old trusty friends who is from Germany. Pro Clima Is a German company. And he gave me a quote for a blower door and then said, by the way would you like a job? And so I was the first one hired out here and my title is technical manager, but it’s more like it’s almost a bit of business development in that trying to encourage a building science industry. So pretty much that’s been my focus – encouraging people to care about air tightness and encouraging them to care about moisture management.

Kelly (02:33):

So now Sean has been a technical manager at Pro Clima for almost four years. He was explaining to me that his job is obviously to sell Pro Clima products, but that day to day, it’s really about educating the market. I’ll let him take it from here.

Sean (02:49):

Currently, standard construction, It’s true in America And it’s definitely true in Australia that there is a race to the bottom for whoever can satisfy the code with the minimum cost and the fastest, the cheapest that you can do satisfy the code. And so there’s a race to the bottom and Pro Clima is only going to sell high performance building products to an industry that cares about high performance. Because if people don’t care about building performance, then you’re never going to sell anything. So we need to educate the market to say, look, these condensation problems that you’re seeing are a result of either too much air tightness with no consideration of ventilation or a poor choice of building envelope materials. There’s lots of, lots of reasons for that. So Australia is going through this painful period here where they’re strengthening their energy code and then noticing these unintended consequences. It’s like a buzz phrase here. Condensation is the other hot topic. So they are learning these lessons that America learned 15 years ago, 20 years ago that you can’t just change one thing in, in the building envelope, like add more insulation and then not pay really strict attention to quality control, like insulation consistency and continuity, and building air tightness, and not end up with major problems. We had a conference here that we’ve been involved in volunteering for, AIRAH, which is the Australian Institute of refrigeration air conditioning and heating, which similar to ASHRAE in the U S and they have a forum each year which has been a lot of fun and a great time to trade ideas with the people who think in a, in a pretty progressive way here. Think about building science, it’s called AIRAH building physics forum, and it’s pretty cool. So I heard through a couple of podcasts Dwayne Johnlin. I heard him on the building science podcast first and he’s, he’s great. And I took so much inspiration from the way that they approached building code in the state of Washington and the Seattle area that I thought this would be a great example for us to copy or take inspiration from to drive how we’re going to do building codes, regulations, standards, labels, things here to drive the industry really inspirational.

Kelly (05:37):

Yeah, that’s great. And we had the host of the building science podcast on as well. And I had talked with him a little bit about Dwayne JohnLynn. We had talked to him when we were updating the New York city energy code. So it’s something I think I’ve mentioned here on this podcast before is most of the things that you’re doing are not new. And so if you can look at what other people have found, even if the research is, you know, little bit of a different location, a little bit of a different climate, there are a lot of translations, I think. So leveraging the mistakes, leveraging the time and money and effort and research dollars that were spent in, in other locations, it’s really important to pick our heads up and see what’s going on around us.

Sean (06:26):

Yeah. there was a lot of opportunity for cooperation, for sure.

Kelly (06:32):

That’s great. And you mentioned codes. We had we had Gayathri on the podcast and she actually mentioned your work trying to get some air ceiling changes to the international energy code. The, that she kind of pushed through on and ultimately was able to pass. And I was wondering, are you still involved in code development in Australia?

Sean (07:01):

We did some good things over the past couple of years, we got blower door testing into the code as an option. It’s not mandatory. It’s sort of like for a while in the IECC the commercial code says you can do a whole building air tightness test, or you can do a bunch of things related to air sealing and definition of air barriers in your building plans and testing to prove it. So it was sort of two, two paths the testing path that was only one option. And so that’s what we got into the building code for both commercial and residential which is good. It’s an option, which some would say, Aw, darn, it’s only an option and it’s not mandatory, but it’s definitely a step in the right direction. And it just lays the groundwork for future progress. So we would consider that success.

Kelly (08:04):

Yeah. And I think there, you kind of alluded too that there’s differing opinions on what makes sense, but I’ve definitely seen that in standards and codes, that progress can be made by soft introductions of, of items and then kind of requiring them as a next generation step. So the next code cycle or the next standard cycle, sometimes then you can shift it up to a requirement.

Sean (08:31):

Yeah. There’s progress. So really I’d like to think about building codes. There’s only one way of changing how things are done. That’s the whole purpose. That’s what your job. And my job has been this for my whole career. It’s been basically how do we improve the quality of construction? So I started out with energy star homes more than 15 years ago, doing blower door tests and insulation inspections and duct tightness tests and ventilation measurements, things like that. I easily have done a thousand blower door tests and that has been our job. You do commissioning now on a much larger scale crazy complexity of projects that you deal with. But that’s pretty much our job, Isn’t it? Just quality control.

Kelly (09:23):

Yeah, absolutely. And I think, so are you saying that there’s there’s codes and standards and then quality control are kind of the two methods?

Sean (09:33):

That’s what codes are, is quality control. So it’s, it’s sort of a minimum. I mean, that’s definitely a minimum quality control. I often smirk and say, well don’t be proud of something that’s built to code because building code is the worst building you can legally build. And it really is. I mean, you can’t build any worse than that and not get in trouble. So there’s nothing to be proud of.

Kelly (10:04):

I actually say further than that, the worst building you can actually build is whatever the enforcement of the energy code is. So it’s actually, it can be worse than the energy code or worse than any other code, as long as those portions of it are not enforced. So that kind of gets to my, my feelings about you know, quality control and enforcement versus having something written down. And I think that’s, from my perspective, kind of in the commissioning world like what you’re talking about now, you sort of live in the space between the drawings and what’s written down on paper and then what kind of comes to fruition and real life and what gets turned over at the end of the day to the building occupants.

Sean (10:48):

Yeah. The energy star homes program. If we just start there, I would say it’s a pretty modest improvement over energy code. Back when I was doing it 15 years ago, it was something like 15% better than code, or maybe 20% better than code. So not that much more stringent, but the quality control meant that you were actually inspecting the installation installation. So it was grade one, grade, two grade, three installation installation, and duct tightness testing and air tightness testing, which those basic steps of quality control like doc tightness testing, which now is building code in many U S States. Of course you should be building your ducts tight. And of course you should be building your your building envelope tight. It’s just sort of assumed or sort of willfully ignored that most standard doesn’t actually do these basic steps of quality control. So yeah. You can’t assume that what you’re getting is even building code you’re, you’re totally right.

Kelly (12:05):

Yeah. And that’s an excellent point. I think I like to give everyone credit. There’s a lot going on in the, in the construction world. And you know, there’s a lot of people moving around in buildings, especially kind of the larger buildings and you’re installing things floor by floor. And did you do that thing before the drywall went up? I’m not sure. And, and sort of a tendency to keep going that I think allows people to sweep things under the rug or sweep things behind the drywall as it were, but but yeah, having those requirements to, to take a look behind the walls, I think are important and kind of moving, moving onto that, you talked, you talk about carrots versus sticks. So let’s get into that a little bit. I would say, you know, maybe I think I know what you mean by carrots and sticks, but maybe define it for us.

Sean (13:02):

I guess you could say carrots and sticks are like incentives and penalties. And a lot of what we talk about, so building codes are basically entirely sticks and in a lot of cases, they’re sort of broken sticks. Some that aren’t really useful at all. So a lot of prescriptive requirements and building codes, if you were to only meet the prescriptive requirements in some building codes, I’ll just give you the example, the, you can download the national construction code 2019 from Australia. The section three point 12.3 of volume two of the residential code. It’s silly how useless this section of the code is for actually getting a building air tightness result. It says things like a roof light, which is like a skylight, a roof light must be sealed or capable of being sealed. And if that’s not ironclad language, I don’t know what is – just kidding. It’s just like, it’s completely useless to actually getting a result from someone. When I’m here I can’t keep pointing to the U S as this pinnacle of how things work correctly, because I know there are a lot of problems there, but at least some of the codes are at least more descriptive about what’s required. So if you look at the prescriptive, there’s a table of prescriptive envelope sealing requirements in the residential in the IECC. So there’s a whole table of things that have to be sealed. And there’s a thermal envelope criteria and an air sealing criteria that have to be met. So if you compare that page versus the couple pages in the Australian code, it’s very big difference in the results that you can expect and the results, obviously that we’re seeing. There’s a huge difference,

Kelly (15:01):

Right. Sticking to the stick for a minute. And the broken stick you, you mentioned. If you could propose, say one to three things for code updates, what would those be?

Sean (15:17):

Mandatory air tightness testing would be a very, very basic and effective step towards better envelope commissioning for this country, and what the number is and what the number you have to meet is what the target is and what leakage limit it is, or what pressure you have to reach. I’d say some of that stuff. So the way that Dwayne John Lynn and the state of Washington did it, and I think is very admirable, is to say, just get the testing started to start testing. And so many things will start happening from there. What happens when you start doing testing is you realize it’s not that scary, and you might actually learn something and that will improve the buildings a lot faster than, you know, more stringent code or, or regulation will. So I took a lot of inspiration from that. So mandatory testing should be in the code. I would say I don’t actually know what it’s like in America with ensuring that ventilation is actually measured, and that’s not a, not a code requirement, but it would be a regulatory requirement on a local level that local jurisdictions say, you have to show that your ventilation systems are actually ventilating. I Mean, I’m from New York, where we did a lot of ventilation studies and found that it was very seldom that ventilation systems, especially in large buildings were working correctly. It was amazing when they were, and it might’ve been just because of the weather. It might’ve been favorable at the time, but it’s really difficult to make them make them consistently work and deliver even just extract the same amount of air from every apartment at the same rate is very difficult.

Kelly (17:15):

Yeah. And I’m sure we have something, a blog post about this or something, but you’re specifically maybe that you wrote about central ventilation systems and multifamily buildings that are sort of notoriously not pulling air from the right spaces and causing indoor air quality issues in apartments.

Sean (17:40):

Yeah. It’s just really difficult to make them work effectively universally. I mean I got to say, to give some understanding to all the builders and mechanical engineers out there that are trying to delivering this thing that, that used to be okay. Like they just put the fan on the roof, connect the duct work to it, put all the registers down this 30 story building, and then it’s supposed to be working. So they’ve done what’s according to the code or as far as it’s enforced, but then once you go there and you take measurements, flow measurements from each apartment, you see that rarely are they actually delivering the nominated ventilation rate from every apartment, very rarely. And that’s it’s just really complicated. It’s just hard to do, so pretty much the, the conclusion we came to is that the more you can get control over all these variables especially in large multi zone buildings like multifamily or a multi-unit residential, the more you can compartmentalize the individual units so that they’re not communicating and creating these networks of air flows that you can’t really predict or control, the more opportunity you have to actually control the ventilation in and out of those units.

Kelly (19:13):

Right. And we can I think we have your study actually on where does make up a air come from. So I’m speaking kind of basically to that there’s the ventilation system itself that you need to make sure it’s working. The fan is actually working. There’s actually a belt If there’s supposed to be, or even better it’s direct drive fans, the duct work is sealed. There’s no gaps or holes in the duct work, basic things like that. And then what you’re saying, the other portion of it, which is compartmentalizing the the apartment itself. Speaking of that, when you’re talking about getting, implementing things in the code, the ventilation test and the air barrier test, are you talking about single family homes or, and, or getting it in the residential code or are you talking about kind of all buildings?

Sean (20:10):

So it’s in the national construction code 2019 as an option for both commercial buildings and residential buildings. So it’s not mandatory anywhere. But what it is taking a step in the right direction where some individual stakeholders, some para regulators you could call them, like green building council has the Greenstar label for mostly commercial buildings. And soon there’ll be a residential single family, detached residential label from green building council they would say, well if you’re going to participate in our program, then you need to take this option, which is a way of progress. So it’s not mandatory, but it’s at least giving, showing a path forward, which is helpful.

Kelly (21:06):

Right. But I mean, you, you were saying what you would recommend to be added to the code for next cycle or future cycles.

Sean (21:14):

Yeah. So number one would be mandatory air tightness testing. And then I would say that I would also recommend mandatory duct tightness testing both in commercial buildings and residential. It’s code for commercial buildings, but very large systems. Maybe it’s 3000 liters per second, so pretty big systems, but I would say you have to do it for any system. I would say that would be a huge step in the right direction.

Kelly (21:52):

Yeah, that’s the same here. It’s only applicable in New York, at least even in the 2020 energy code. That was one thing I would have loved to see is mandatory duct tightness testing for low pressure ductwork. But right now it’s only required on ductwork greater than three inches, I believe.

Sean (22:11):

I mean, there’d be some other things that I would recommend not just in the commissioning things, but I, it’s pretty amazing to me that single pane glazing is still the norm here for most of this country. And then Australia wonders, there’s whole working groups. My colleague, Jesse Clark from Pro Clima here is a wizard with moisture analysis. He’s on the condensation working group for the building code. They have a condensation working group. Let that take note of that. And I think it’s no wonder that you get condensation in a lot of buildings in Australia because we have no attention to building air tightness, no attention to ventilation, at least as installed. And you might write it on the code to say, you need ventilation, or you need this much ventilation, ASA 1668 is the ventilation standard. But there’s no mandatory, constant ventilation like there is in ASHRAE 62.2. So you’re not diluting moisture from the space. And then there’s thermal bridging all over the place. The biggest thermal bridge I can think of is single pane glazing everywhere. And you get condensation, these brand new buildings going up in Sydney, lots of construction going on all in all the big cities in Australia. And they wonder, why are we getting condensation everywhere, this condensation problem, but some of the building materials that are being used there’s foils everywhere. Can you believe they use these reflective foils in walls on, and it’s just standard construction to use these reflective foils on the outside of walls. Maybe you don’t think about this that often I’m doing mostly mechanical work, but they use these for the building envelope here. It’s standard practice to use a cheap S aluminum foil backed polyester.

Sean (24:27):

They call it sarking here. And it’s a foil backed membrane that they put on the outside of every wall while they’re doing construction here and it stays in there. And then this is a very, very effective vapor barrier, and it’s on the cold side of the installation. So if you have any air leaks, which again, they don’t do any air tightness testing and you start adding more insulation, you start creating a dewpoint on that cold metalized surface in these walls. And of course you’re going to get condensation. Of course. So that would be another thing if I could just, you know, write a big red line in red text, no foils on the outside of the building envelope in some climate zones, it’s just obvious.

Kelly (25:20):

Okay. That the new code is written by Sean Maxwell.

Sean (25:25):

And there are a lot of other people who think the same way. I mean, so Jesse Clark here, have you ever heard of Wufi?

Kelly (25:32):

Yes, but maybe you should explain for our listeners

Sean (25:36):

Sure. Wufi is w U F I. So it’s moisture analysis for building envelopes and a lot of work. It’s really, really excellent work that’s been validated by real world data again and again, and again, it’s been around for a long time. It was started in Germany. Jesse Clark has been to Germany a few times and been to the Institute to talk to them. Hartwick Console, One of the creators of Wufi has been to Australia to speak and lead workshops on, on Wufi. And they are sort of puzzled as to why we’re still using things like foils in walls in climates like Sydney and then not doing anything related to building air tightness. So some really basic steps of building envelope commissioning are missing.

Kelly (26:44):

And to talk about the issues with codes. So talk to me a little bit more about the green building council there and what they can do to maybe incentivize better performance, or if there’s other incentives there to kind of pull the carrot out.

Sean (27:04):

Well. So we had some folks from green building council come when we had our trainings with Attma, the air tightness testing and measurement association. So it’s a way to unite all of our air tightness testers in this country and make new testers to expand this industry. And that’s been, been good. We invited green building council to meet some of them. Some of the really committed ones, the level two testers who can test larger buildings or more complex buildings. And we just looked around the room and said, you know what, all of us, everyone in this room right now is standing here because of a green building council and people like them. They are for all of their faults, they are definitely driving the market towards a better place. They’re trying to push what’s considered sustainable. What’s considered a energy efficient and trying to push that definition to be more stringent. And that’s really admirable. And we have to give them a lot of credit for that.

Kelly (28:13):

Great. And where do you see that interplay between the sort of setting the green standard and then you know, holding the minimum. Where do you see those two things interacting and what do you think belongs in, in one bucket or another?

Sean (28:31):

Well, so green building council has tried to do they’re trying to use carrots and sticks themselves. So one of the sticks that they’ve put in one of their, in their more recent versions of Greenstar – that’s their label like LEED is the the program from the USGBC. So they’ve tried to put air tightness testing in the commissioning credits which it is it’s building envelope, commissioning, which is good, but the way it’s happened is that most projects because no one has the awareness of what this means, A project will say, well, you want Greenstar on this? Okay. There’s a 10% premium on, on this because we have to use more expensive flooring materials and different paints and more paperwork and stuff. That’s a lot of what happens with green building labels, but then the commissioning process, the commissioning credits basically get lumped in with the mechanical contract and the mechanical systems contract. But this is the situation where the mechanical contractor now has this credit, that they don’t know what it is and they don’t care. They just want it done. They just want to know how much is this going to cost, because I just want this out of my hair. It’s just a problem for me. And so unfortunately the air tightness test gets put right to the end of the project. And then you get a terrible result because no one’s paid any attention to building envelope, and then everyone’s pointing fingers. And so I would say to GBCA, I would say, take some inspiration from the city of Seattle, just do an air tightness test. Don’t put a limit on it. Say, all we want you to do is do a proper test and do a whole building test where you get a real sense of the building envelope as a whole functioning, as it would in real life.

Sean (30:46):

And then write down the number. No one’s going to criticize you for what the number is, but we just want you to be there to see it, to see what the problems are and to learn for next time things you can foresee and avoid next time. Because what happens is they’ve said you can do the you can get the credit and you can get good practice or best practice credits by only testing 10% or 20% of the building envelope, which again, bringing this back to scale of a house. If you said, we’ll give you a credit for only testing one bedroom in your house. And if you can say that that bedroom is has a permeability of 3 air changes per hour or less for that one bedroom, then you get credit for doing best practice air tightness for that whole house.

Sean (31:39):

You’d say, what that doesnt make any sense? You’re only testing one bedroom. That’s not indicative of the whole house. So if I could scratch a whole bunch of those things out these requirements, and then put it sort of start from the beginning and say, let’s do something more constructive and educational and incentive the industry in a different way. So get rid of some of these broken sticks that you have and start doing things like incentivizing, say schematic design reviews, design development reviews for a building envelope that would be actual commissioning, and then you would actually get better, better buildings that way. So a definition of an air barrier, just to schematic design, schematic outline of where they, what the separation between conditioned and unconditioned spaces, is that sort of what you would think is the most basic thing that of course happens, It doesn’t happen in most projects. I tested a warehouse building where they had a big refrigerated warehouse and then an office building attached to it. Well, there were holes so big that you could literally crawl through them into the refrigerated warehouse area. And I bet the people in the office are cold because they’re being refrigerated. This building had a permeability of like 22. So that’s really, really bad. And so they were worried that they weren’t going to get their Greenstar credit. Well, the thing that you should focus on is the early intervention. So plan reviews, some inspections all the testers have seen all these problems before. And if they’re walking through, you should be incentivizing them to walk through and point out all the problems that they see. Cause that’s where you’re gonna make the actual gains.

Kelly (33:40):

Yeah. You talked a little bit about getting certain things into the code and getting certain things into the green standard. Would you say that like the final test is something that’s easier to be regulated as kind of a stick under a code and that these sort of early design reviews and inspections along the way are something that are easier to be regulated as kind of a carrot under an you know, a green program.

Sean (34:08):

Yeah. That’s, that’s the way it is. Yeah. So it’s, in fact that’s really the only place for a numerical quantitative test is in something like a building code where you say, this is a number that you have to meet and then do the test and show me the number, show me the certificate and that’s proof that belongs in the building code, all the other stuff, which is the whole process of actually designing and building a building. That’s not something that is easily very cleanly and clearly defined and regulated. So it’s more industry development and education. So the awesome thing about air tightness testing is Kelly. You’ve been you’ve done many tests yourself, right. And with the blower door over the years, many apartment air tightness tests. Do you remember your first one? Yeah. And was it, was it cool or was it just exactly what you’d expect?

Kelly (35:04):

I think it was pretty cool. And I think, I didn’t exactly know what to do. I’m actually like reasonably sure that I was testing with somebody else and we had to phone a friend cause we didn’t actually know how to work the blower door and the friend might’ve been you. I’m not sure. The quantitative testing is interesting, but the qualitative testing is really interesting. Right. So that you can run the test and then you can go around and find the leaks. Sometimes it’s, it’s more straightforward than finding the issues in a mechanical system. Sometimes it’s not, but but it’s like straightforward, right? Like you put the fan in the door and then you can see where the leaks are. And I think actually the more gratifying thing for me is when you have construction teams in the room and, you know, you’re sort of showing the cracks and where there might be issues. And they’re like, yeah, yeah, I don’t think so. Like I don’t think so. That goes to that. Doesn’t go to the apartment next door. That just is internal. Like we’re not worried about that. And then you turn on the fan and it’s like, Oh, okay. I guess it is coming from, you know, the apartment next door or the outside or whatever.

Sean (36:17):

Yeah. Once you get some experience with doing the testing, you start to learn where the problem originates. You start to think going back in time where the design over design oversight was the really awesome thing about a blower door test is that it’s numerical, it’s quantitative. So you can get a number which is useful, but it’s also, like you said, it’s great to have the whole project team there and to be able to show them Holy cow show them all these leaks. So we did a test with a green building council here in downtown Sydney. It was eight story building and helped a sustainability house, Suhou do the test. I was just a hand to help them. And as part of it, I brought my fog machine. And as I was expecting, the roof parapet is often a weak point in a lot of commercial buildings.

Sean (37:16):

So we were out on the veranda, outside the roof, parapet on the top floor and with the building under negative pressure, I stood outside with the fog machine and shot fog at the roof parapet. And sure enough fog gets sucked in through the ceiling, through the roof, through the ceiling. And then coming out of all the light fixtures in this meeting area on the top of this building. I bet 10 years from now you will see little traces of dust on those light fixtures where the air is leaving, leaving those light fixtures and leaving the dust as it goes because it’s going out and up and out the top of the building or vice versa in the summertime. But to see all the people there from the design team, the consultants from green building council to see them walk around and say, what, why is there fog coming out of these lights right now? That’s crazy. He’s outside right now. And we’re inside, and fog is coming out of the lights. Why is that happening? It’s so eye opening to see this process you can touch and feel the air leaks like some of them are so big that you can take a piece of like toilet paper, like single-ply toilet paper, pretty much. The only thing it’s good for is showing air leaks. So you can put it on use a piece of single ply toilet paper and then hold it against these air leaks. And you’ll see it’s fluttering in the wind. And it just makes someone’s eyes go wide and say, wow, that’s supposed to be a fire separation there. This is supposed to be a smoke extract smoke exhaust, like a pressurized stairwell here. And here is a piece of toilet paper whistling in the wind. That’s a problem. And it’s just, it’s so it’s a quantitative test, which is very powerful for regulation, but it’s also qualitative in that you can touch and feel and find and fix air leaks. So it’s pretty, pretty awesome process.

Kelly (39:29):

Yeah. And actually you were, you’re kind of talking about fire separation and we’ve talked about lower door testing on the whole building and blower door testing on an individual apartment. And I’m curious to get your thoughts. So you are a proponent of testing individual apartments. Can you describe for everybody kind of obviously the exterior envelope, if we’re talking about energy, the exterior envelope is, is matters a lot. Can you talk about what the impact is on the apartment level envelope and where, you know, why you think that test is just as important or maybe could be used as well.

Sean (40:11):

Sure. Well, I’d say theres very little correlation between the exterior envelope air leakage number that you get and the individual apartment compartment test. So I was contacted by some people in California who wanted to do a research project to say, if you do a sample of apartment tests can you somehow correlate that with a whole building envelope leakage? And I’d say, definitely not. Maybe you might be able to draw some conclusions based on different construction types, like like building really broad construction systems like concrete or steel frame wood-framed he might be able to see some differences between them, but for the most part, there’s very little correlation between compartment testing results and the whole building exterior envelope results. And you’re right, that the one that most directly relates to building envelope energy use is exterior envelope leakage only not the individual compartment tests, but there’s a couple of reasons why I am a proponent of compartment testing.

Sean (41:18):

Number one was maybe it’s shortsighted. But I’d say I, I was thinking this is definitely more digestible to a building industry that if they to do a test on a whole building if you did test on individual units, the cost of doing that as a fraction of the cost of doing a whole building test in some buildings, but as testing industry capacity grows doing a test on even a very large building is not that difficult. So that’s maybe not a great argument, but from doing research over the years at SWA in New York we found many of the building large multifamily building problems were related to poor compartmentalization. So ventilation systems work much, much better when they serve a bunch of independent compartments rather than what happens with a large building is you get this where there’s poor separation between the compartments.

Sean (42:25):

You got lots of very complex networks of air leakage. And so, and you can see this in the middle of winter on a cold, still day in winter in New York, you’ll see people on the top floor have their windows open because it’s so stinking hot on the top of the building. And then the people on the bottom floor are cold because because of stack effect, the air is getting sucked in the bottom of the building and making the people on the bottom cold. And so the building super turns, the heat up changes the set point so that the people on the bottom are satisfied. But as a result, the people at the top are way overheated because all this warm air from the rest of the building is then spilling out the top. The only way that the people on the top are going to get relief is if basically all of the air from the building is evacuated, and finally they reach a comfortable temperature at the top. So it just makes that whole stack effect dynamic is made much, much worse by poorly compartment buildings. So for fire safety, for energy use for sound transmission, for pest reduction for noise, there’s so many really, really good reasons to compartment compartmentalize your multi compartment buildings that w whatever the fastest way to get reduce energy use is in the code. It just makes a lot of sense for so many other reasons to be tightly compartment doing units.

Kelly (44:07):

Great. And taking us back to Attma, you mentioned kind of earlier that you worked for them one day a week, do they regulate kind of exterior envelope testing, or do they get involved in compartmentalization as well?

Sean (44:21):

You could Do compartment testing, You could do either through them. So a single zone test would fall under Attma TSLOne. Basically the way to think about it as a level one tester knows how to use one fan in a single zone, simple, small building. So an apartment house, a small commercial building, one fan, a level two tester knows how to use two fans or more so a larger building requiring more equipment, a leakier building a building just because of its size needs more than one fan. That’s another level of usually level of complexity with building envelope, calculations, equipment preparation experience, lots of reasons why that’d be level two and then level three would be a, it’s basically a PhD in air tightness testing. So currently there are no level three testers but that’s how they, well, it’s basically that a lot of the level two testers should be considered level three. They just haven’t gotten around to haven’t needed to yet really clearly defined who’s qualified as level three

Kelly (45:36):

And it just the Greenstar standard that’s requiring ATTMA my testing, or is it referenced in the code?

Sean (45:47):

So ATTMA itself probably won’t be referenced in the code just like in the U S in the IECC hers rater or BPI tester is not referenced in the code. But it might be understood by local code officials that that’s, who you accept a result from is a RESNET hers rater and that you shouldn’t, you should treat with suspicion, just any random blower door test that you get from someone who’s not a part of, one of those schemes. So it won’t go into the code, ATTMA Specifically, but it would be what we’re trying to do is build relationships with individual stakeholders. So a green building council with individual councils, which are like small, smaller than County level government bodies here in Australia. So local, local governments that might incentivize things, and we’d say, or say a pilot program, if you want to start incentivizing this best practice do it for every registered certificate of air permeability test from Attma, you can get a credit or a refund of say a hundred dollars or something to drive the cost of the testing down and make it more attractive.

Kelly (47:06):

And so if you had the entire audience of Australia now, what would you like the general building industry to take away from this discussion?

Sean (47:17):

So if there were one thing that I would say one good place to start, it would be at the very beginning for any project team, it would be witness a test by an Attma tester. So same advice for someone from building codes board for someone from individual governments, from green building council, from individual consultants, from homeowners, from builders, just witness an Attma test, and you’ll learn so much about how the process happens. And then even more importantly, the things that you’ll find the problems that will be revealed by this whole process. And you’ll also get a number that you can compare then from your building to the next building, to the next building, to building code. So it’s really powerful process very well regulated. And this is a piece that you can be put into the regulatory framework, and it’s also really constructive useful feedback for everyone involved in the project.

Kelly (48:24):

And do you do you do sample test for different people to witness?

Sean (48:30):

So through Pro Clima, my employer, I’ve done tests for individual builders in Australia to show them here’s where you are currently. And here’s some things that you can fix. And then, I mean, for any, anyone who is trying to push building performance product sales or whatever it is you could say, look at the things we found with the blower door and here’s how you can fix them. And by the way, we can sell your products to help you fix that. Absolutely. So for, for builders, builders or product sales, it’s a great sales tool for consultants. It’s a great tool to say, look, we could have helped you find these problems on your building plans and help you avoid them next time. And then for, for manufacturers to say, look, we, our systems, have we have this panelized system that goes together with tight fitting joints, here’s this brochure of our new system, a curtain wall system or whatever it is, the air tightness test as a sales tool is an amazing ally.

Kelly (49:45):

Right? Absolutely. And so Sean, if we have you back on the podcast in five years, what do you think we would be talking about then?

Sean (49:56):

Hmm, well, what we’re going to be talking about is some of the awesome data that’s going to come from ATTMA. So pretty much the whole reason that I started talking to them is that I guess four years ago, five years ago now was that they made this tool called ATTMA lodgement, which is an online database where you submit your results and it goes, it goes through some quick quality checks to say, what’s your R squared, what’s your N it does some data checks to say, does your test result make sense? And then it spits out a registered air permeability certificate. And when you do that, you contribute your data to lodgement. It goes into a database. Now this might blow your mind. I hope it does. They started this database four years ago or something, and very quickly, it just, it was a runaway success.

Sean (50:58):

So they have now in just over four years, over 750,000 test results in their database, 750,000 test results, 750,000 test results. It’s crazy. And they’re making it easier and easier and easier all the time. So it’s amazing for so many reasons. Cause you have all this data to then draw some really solid conclusions about build quality about policy effectiveness, about building systems that are being used. So in the UK, you lodge what type of building system it is. So whether you’re building with wood-framed or timber, they call it or masonry construction, steel framed. You can draw some pretty clear conclusions from this stuff when you have data sets that are that large. So it’s crazy how big this is. So what’s the most interesting thing you found in the data? Well I think it’s pretty, this is a common point of argument and discussion is that if you look at the results you see so in the UK, you have to define what the air permeability is before you do your project.

Sean (52:11):

So say a common target is a permeability of five, which is about five ACH. So you say we are going to build this building with a permeability of five, that’s our target. And then we’re going to do the test. And what you see is that most of the, the results are about between 4.9 and five, which tells you that either the builders are really good at getting right on target or they are just slightly missing the Mark and then do just enough to get them over, down to that five limit. You can look at that in two ways you could say, well, the builders are clearly, they only do exactly the minimum required and the just scraping by which in some cases it’s true, but it also, you could look at it in another way, which is to say, this is clearly a market mechanism and market driving mechanism at work here.

Sean (53:02):

It is incentivizing a best practice here of this air Tightness target. And then how you meet that target is up to you. Whether you want to use a better membrane or better tapes or a rigid air barrier on the outside, or a self adhered WRB, whatever, whatever strategy use it’s your choice to do that. And so it unleashes the power of innovation, I think. And also, so I think seeing some broad datasets for Australia, it would be really, really awesome. So looking at different building types and there are some things, some certain practices, I won’t name them now that we think are pretty poor. And we just want to use this data to show what works and what doesn’t. So in five years from now, I’ll be able to show you some pretty cool results.

Kelly (54:00):

Okay. So you have that data in there already, but you’re waiting for more.

Sean (54:04):

We don’t have much data. There’s about a thousand test results from Australia so far. But a lot of the data is, you know, good performers, people who are actually trying, which doesn’t give a fair gauge on what standard practices.

Kelly (54:20):

Gotcha. So that’s 750,000 is around the world?

Sean (54:23):

Those are just from the UK. Doesn’t that blow your mind?

Kelly (54:28):

That does blow my mind. Yeah.

Sean (54:29):

So it’s basically, they’re getting close to 100% testing of all buildings in the UK

Kelly (54:38):

And that’s whole building testing, or that includes dwelling unit testing as well?

Sean (54:42):


Kelly (54:43):

Got it. So, okay. I was going to say, that’s not really a five year plan if you already have it.

Sean (54:47):

Well, we don’t have it. The UK has that regulation in place to require that. In Australia, what we’re doing over the next five years is trying to work with these stake holders to say, look, here’s a path we can see forward and if a stakeholder might be in an individual state that says, alright, it’s optional to do an air tightness test in our state. But if you want to use this energy modeling path, the performance path, you have to do a test to prove that you met the target that you set for yourself at the beginning. That’s one way to do it. And then I just can’t wait to see all the data.

Kelly (55:20):

All right. That sounds great.

Sean (55:22):

Yeah. I’m really excited about it.

Kelly (55:24):

Well, we look forward to hearing all about it in five years when we have you back on the podcast. Thanks for joining us today.

Sean (55:32):

It was awesome. And I miss all the really awesome people at SWA and all the great work that you guys do. And if I were back in America I would love to work with you guys again, but I would still be pushing you all to join Attma as well.

Kelly (55:52):

That sounds great. And you are welcome back. Anytime Sean. Buildings and beyond is brought to you by Steven winter associates, we believe that our world is not as sustainable, healthy, safe, equitable, or inclusive as it needs to be. We continually strive to develop and implement innovative solutions to improve the built environment. If you want to join us in our mission, visit A big shout out to our production team, Jayd Alvarez, Dylan Martello, Alex, Mirabile, Heather Breslin, as well as my cohost, Rob Aldrich. We all thank you very much for listening. And we look forward to seeing you next time.


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