#1.2 - Max Sherman: The performance gap, mentoring, and pollutants.

Part 2

Max Sherman was a senior scientist at  Lawrence Berkeley National Laboratory in California, retiring in 2016  where he ran a research group for over 30 years.

It is hard to overplay the impact Max has had in our sector; even a cursory look at published papers on airtightness and infiltration, air quality or ventilation it's no surprise to see Max as an author, co-author or cited at some point in the work.

He has been a long-standing contributor to standards through ASHRAE 

Recipient of the Distinguished Fellow Award, Environmental Health Award, and Exceptional Service Award.  

He is a former member of the board.  Currently Vice-Chair of 241 a standard on the control of infectious aerosols and member of the Environmental Health Committee

In part 2, we discuss the performance gap, the age of digital feedback loops and how they may influence ventilation outcomes or not. We dive into the value of harm for pollutants and the value or not of monitoring TVOC and PM.

Lawrence Berkley National Laboratory https://www.lbl.gov/

American Society of Heating, Refrigerating and Air Conditioning Engineers https://www.ashrae.org/

ASHRAE 241 https://www.ashrae.org/technical-resources/bookstore/ashrae-standard-241-control-of-infectious-aerosols

Air Infiltration and Ventilation Centre (AIVC) https://www.aivc.org/

Transcript

Simon: 0:00

Welcome to Air Quality Matters. This is a conversation with Max Sherman, part two. Some colleagues of ours in France, in Cerema, have been looking at the inspection of existing non-residential buildings and largely the conclusion is it's almost a complete waste of trying to measure the performance of the existing ventilation systems because they were never designed to be inspected. There aren't the skills to inspect them and even if you did, you're probably not going to like the results, so they may well fall back to air quality monitoring. This isn't a European problem. This is a global problem with ventilation in general. Where do you think that performance gap stems from, being that most ventilation systems are currently run to failure? We only really think about it when it starts making a noise or stops working. How do we start to address that? Or how do organizations like ASHRAE and AIVC and CYBSE and others start to change the narrative that these systems are a central pillar to good outcomes in the built environment?

Max: 1:35

Well, a lot of it stems from the basic system that we use. It's not limited to ventilation or, for that matter, even buildings. Regulation is the least, is the worst thing you can do, allowed by law. That's the definition of a code, and if you are in business of providing a building or other activity and you want to comply with codes, you want to do that in the least costig way possible, because that makes you the most competitive in the marketplace. So you're being rewarded for cost reduction and you try to come up as close as you can to the line that's allowed, or worse, if you want to try to get away with things. But let's assume that people try to, in fact try to meet code. But code doesn't require that it continue to operate that way. Even so, even if it, when it was first built, if it does what you want it to do, there's no guarantee that it's going to continue to do that, and there's probably a guarantee that it's not over time, because there's no incentive to do that until somebody complains, and so the complaints become the thing that you respond to. Now, commissioning has always been felt to be an important part of doing this, so you should commission a building to make sure it meets the design intent before people move into it. But you should probably also recommission it on regular intervals to make sure it continues to provide that and have some mechanism to make it comply if it doesn't. Those are ways which has often been talked about to do it. That's just one of the specific ways of using performance as a metric to get what you want rather than one time regulation, but we're built on one time regulation in most of the world.

Simon: 3:37

Yeah, and in my experience, organizations or processes that transfer from code specification to performance specification. It could be transformative for outcomes because all of a sudden, you're now thinking about what does good actually look like, as opposed to what's the minimum I need to do to meet a mark. I mean, I've always said that the trouble with minimum standards is if you set up the supply chain to just meet the minimum standard, any failure in that supply chain means automatic failure to meet the minimum standard, whereas if you say now I don't care how you get there, but this is the target you need to hit and you will be tested on it, that changes the narrative slightly. One of the other things that changes the narrative is the digital world, of course. So we're now starting to think in terms of the ongoing performance of our spaces through digital feedback loops, whether that be the mechanical performance of devices or the air quality outcomes. Do you see organizations like ASHRAE and others starting to get their head around this change in the built environment towards the digital? That while the tools we use to measure things like air quality might be imperfect at the moment, they're already proliferating out there and actually standards will become less important. Commissioning standards may become less important, that actually you may start being judged on the ongoing performance of your building. Is that a mind shift that you could see coming to organizations that they start to think in those kind of terms?

Max: 5:32

I think you could see that in individuals having this understanding of how it works. The building industry is very conservative. I don't mean in a political sense, I mean that it changes very slowly. In part that's a good thing, because much of the building industry is built on experience and learning and doing things the way they were done before, not on first principles, scientific derivation of how to build a building, and so you often see if you move too quickly you have really bad unintended consequences. I've seen several amusing instances of this over my career where seemingly good things were done that had horrible unintended consequences. So the industry will tend to move very slowly in this regard. The industry, the architectural engineering professions they don't get paid for performance right now. They get paid for design and construction and so they're not going to be motivated to change what they do until that. And the same thing with the builders and owners. They just they want to build something as cheaply as they can to make a decent profit. So until the motivations change, either through regulation or incentives or whatever, it's going to be very slow to happen.

Simon: 7:00

Yes, it's a very good point and it's that, it's that passing on of knowledge and that conservatism and hierarchy within construction that makes it quite conservative. I think one area that might push that a little bit is the people that fund construction and assets, because certainly increasingly they're now looking at performance, because the asset value is now increasingly tied to its energy performance and possibly soon, the health and well being outcomes that that building can provide. So in those terms, my experience generally is being when the money starts moving, everybody follows. So we see that particularly in Europe, for example with the SG and things like the EU taxonomy are very much shifting the thinking of very traditional organizations like developers and contractors and main contractors to having to think in a different way. So we'll see, time will tell. It would be an interesting, interesting thing to watch.

Max: 8:11

Yes, I think if you can get the, the asset values to move, you get the money to move. You will drag people along. Some will be kicking and screaming, but but they will begin to move. Until that happens, it's unlikely to have very much. There will still be the bleeding edge of people who really, really want to do a good job for themselves, who will, who will try and they will sort of show us that it can be done. But the bulk of people need better motivation than that.

Simon: 8:40

Just turning back to you for a short while I mean you're now, quote unquote, retired, that you seem very busy to me. What do you think, because you've obviously had people that have inspired you during that time as well what do you think makes a good mentor in this space, because we need all the good mentors we can get if we're going to keep progressing. What do you think you brought, and what do you think others can bring, to keep bringing people on and pushing them to innovate and research?

Max: 9:18

I'm not a big fan of the word mentor because it gets overused a bunch, but accepting that there are some basic mentoring skills, that those, those, those can be taught on how to deal with people and help them become better versions of themselves. But to me, to be a great mentor requires something more than that. It requires a sort of connection between the, the two people, where each can see a part of the other in themselves, or vice versa, and therefore be much more open to exchanging views and being constructive. And so I think the few people that I've felt particularly good about mentoring that's always been the case that they can see themselves in me and I can see myself in them in a way that that helps provide some guidance, because mentors can't tell anybody what to do. They have to offer a piece of themselves that's been successful in the space, and the other person has to be willing to learn from that. Maybe not take it all, but learn. Learn from that, and that's that's, to me, what great mentoring is all about.

Simon: 10:42

And a lot of that, I guess, comes from the relationship you have with people, and that's hard to engineer right. You know the if you don't have that relationship, regardless of the knowledge that you hold very difficult to constructively engage with people without the right relationship.

Max: 10:59

Right, you can be an exemplar for somebody without knowing each other. They can. The younger one can follow the older one. But to be a mentor requires, yes, being being engaged directly, perhaps something we lose in the virtual meeting space. I know one of one of my mentors. It was a completely accidental meeting that, where it happened, I was a graduate student, I was working with my dissertation and I needed to get some information about wind behavior in order to model infiltration. So I went to a national wind engineering conference to hear some talks and talk to some people, and it was a rather large conference and I was in one of the, I guess, plenary sessions or big sessions and somebody came up and asked a question that I thought was a really good question, especially compared to the other questions that had been asked that I thought was insightful and useful, and I went over to them at the reception that evening to chitchat and that started a long-term relationship that would be, I guess, a mentoring-like relationship, because we hit it off. Even though we weren't working in exactly the same field. There was enough overlap that it worked just well, just fine.

Simon: 12:29

And if you were starting your career now, or advising somebody that was starting their career now, what areas would you be pointing them to right now? I mean, where do you think the progress is going to be made or the innovation is going to come from, or the impact will be?

Max: 12:54

Well, that's always hard to know and, as I've said, in my own career I haven't been able to predict that very well at all until in fact it happens. It became clear to me that air tightness was important for energy. It became clear to me that ventilation was going to be important when air tightness had its way. It became clear that we'd have to look at contaminants if we hoped to make inter-air quality be energy and cost-effective. And then, most recently, the infectious control. So I think you have to place yourself in a good spot. At least that's always been my approach. You have to have the skills that you think you're going to need to do the kinds of things you want to do, and then put yourself in a place where good things can happen. Now, not everybody is good at that. Some people know what they want, they have a passion already, and the same sort of thing applies Teach yourself the skills or learn the skills that you need, and then put yourself in a place where you can enable some good progress on your passion. Now, what that is in this field, I could speculate on, but I wouldn't put much weight in it. Clearly, we're still working on the contaminant level sorts of things. We know, for example, that particles are the largest source of harm in the indoor environment population-wide. So clearly there's going to be a lot of work in that space in the future. If people want a higher indoor air quality levels than they've had in the past, it's going to require clever systems to do that, whether that be contaminant control or infection control. All these things are going to become important. If we look back in history, it's been cyclical as to what it is that humans had to focus on to improve their lot. One was not dying because you got choked by a fire, not getting infection, not being in a stinky environment to the kinds of points we have today. So I think there's going to be a lot there. We're going to be transitioning to renewable energies, obviously, so that whole sector has to be developed further if we're going to get rid of fossil fuels, and we have to do that in a smart way not in a political way, but in a smart way. So there's all sorts of areas we need to work in.

Simon: 15:35

And I think anybody looking at it, I would guess the upgrading and the renewal and the retrofit of our existing stock is a very particular challenge. We're sitting on. The vast majority of the buildings that we occupy today are the buildings that we want to improve the performance of in the next 10, 20, 30 years, and we haven't done ventilation very well to date. So innovation and understanding and knowledge in that space has got to be an area for research, I would assume Right.

Max: 16:17

I have always focused on retrofit versus new construction over the years, because most of the buildings that will exist 20 years ago or 20 years from now are already built so, and most of the buildings we're building now are much more efficient than the average stock. So the focus has to be on the existing building stock and improving that. That's where the big savings are. Unfortunately, it's much more difficult because each building is its own project. It's not. It's not like you can design it from scratch like you can a new building, which is why people are focused on new construction. It's much easier to get a handle on, but the energy to be saved is in the existing building stock.

Simon: 17:00

What do you think? What do you think a success story would be in five years time if we were looking at ventilation and air quality, either the knowledge and what we've learned, or where we've come from a standards perspective.

Max: 17:19

Well, I'll tell you, I set myself 10 years ago. I set myself a pseudo goal that by April 3rd, 2034, very specific date the word ventilation wouldn't be in indoor air quality standards, at least in any significant way, that we would have transitioned away from ventilation as being the thing that we focus on, as opposed to health and indoor air quality as being the thing that we focus on. That date happens to be my 80th birthday, which is why I picked it, so we are making progress towards that goal. We are already understanding that we why we ventilate and when we should ventilate we don't yet know all we need to know to get to where I was we. We don't have the, let's say, the sensors that are cheap and easy enough to monitor the things we monitor, but we are making progress along that, that route, so I expect to see continued progress. I mentioned that in 2010, 11 and 12, we came out with the first dolly work. Well, the next generation of dolly work is is hitting the streets now, where we have better data still. The, the answers writ large are not that different particles are still the most important thing, but we've learned a lot more and we can do things more quantitatively than we could before. So we are continuing to make progress and I think that will happen. We have to avoid pitfalls. One of the things that I'm always trying to be cynical about is what are the pitfalls in any new thing that we approach? For example, we do not want to electrify existing buildings too quickly. Right now there are huge problems with doing that. The grid can't always take it, the building infrastructure can't always take it. Plus, marginal electricity generation unless perhaps you live in France is all done by fossil fuels. So if you stop, let's say, heating with gas in your home and heat with electricity, the power plant may just have to start burning gas in order to supply the electricity that you use. That can be a lose-lose situation. These are some of the things I think we need to avoid for the short term, because obviously we're going to get that way, but not until the grid becomes sustainable and quite green. Can we actually push too hard on some of these areas? On the other hand, when you're building new buildings in a new area, it may not make sense to put in gas. Infrastructure May want to simply go electric. It certainly makes sense to go to electric in cars because they're so polluting. So you have to look at things carefully, and that sort of being skeptical of new things is something I've always tried to keep in mind when making progress.

Simon: 20:32

And in North America? Does that kind of grown-up thinking happen at a national level or does that happen at a local level? Do you think no, it?

Max: 20:42

doesn't. It doesn't tend to happen actually at all. That's part of the problem. The Department of Energy, for example, is going full bore with electrification of existing buildings Other things in California. It's got a lot of political power behind it, and grown-up thinking tends to go by the wayside when there's political power behind a particular activity. Same thing perhaps has happened in Europe, where there's quite a buy-in on natural ventilation. But natural ventilation is becoming less and less effective, not only because Europe is warming up and needs more mechanical cooling, but also because the air is becoming more polluted, and when you're talking about infection control, that's it. But there's a lot of political support in Europe for natural ventilation, and so it's not so easy to be skeptical about it.

Simon: 21:44

Yeah, interesting. And perhaps the opposite might be true of a lot of places within North America where when we talk about ventilation and duct work in Europe we specifically mean ventilation and we tend to heat our buildings through wet heating systems, Whereas in North America, if I say duct to somebody, the automatic assumption is that's where your air conditioning and heating comes through, that ventilation systems for the pure purpose of ventilating can be quite rare.

Max: 22:19

Right, but it's not North America that you're comparing it to. I agree with what you said, but it's cooling climates, that is. We used to have a lot of wet systems, still do in some parts of the country. These are parts that don't have to worry about cooling in the summer and don't have central cooling systems. But most of the United States is pretty warm, and if you look at other warm places, let's say Singapore, you see that the ventilation is always integrated with the heating and cooling system, because you need a ducted heating and cooling system anyway. So the easiest thing to do is integrate the ventilation along with it. That's the most cost-effective thing. The difference here is that you can get away with radiant or baseboard or steam systems when you don't have to worry about cooling other than maybe having some window-shaking unit in one bedroom for the five days a year where it's necessary. But as cities heat up, as the climate heats up, there's going to be more and more demand in those climates to have significant cooling systems, and once you do, then you're talking about duct systems that can work 365 days a year and therefore ventilation can make sense integrating with it.

Simon: 23:42

One of the things I wanted to ask you, max, was when we start to talk about the built environment. It has changed significantly over the last few decades and one of the things that have concerned to people is the types of products we now bring into our building between chemicals and cleaners, and furniture products and plastics. There's a whole range of things that make the air chemistry, if you like, much more complex perhaps than it used to be, and we talk about that and frame that as VOCs typically. So for people that don't know what that is, that's a volatile organic compound, that's the gases that are released from particular chemicals, that typically at room temperature, and one of the ways that we frame that and we see that in our regulations here is TVOCs, and that's the term that's used to describe a collection of chemicals, if you like. Do you have a comment on that? Because TVOCs has been a contentious subject, particularly over the last few years, as we've seen the ability to measure them with low cost sensors.

Max: 24:58

Sure, so backing up a little bit. Volatile organic compounds can be very important in the air environment. There are thousands of them in the indoor environment. We know that for the population as a whole, at least for today, the most important one is formaldehyde. That's the one that seems to have the biggest impact on people. But there are many others and there's always new ones being introduced that we don't know what their impact is. They have to be studied. So that's an ongoing thing to differentiate and study some of the things that we're bringing into the indoor environment. Tvocs was an attempt to have one number to describe all these things in terms of harm. So what TVOC is supposed to be is the total mass of volatile organic compounds in the air per liter or whatever, per cubic meter, whatever you like, but the total amount. Now A? The sensors that claim to measure TVOCs don't. They don't measure that number anyway. They're different, sensitive to different compounds. But even if they did measure the right thing, that number is less than useful because you don't know what it is. Ethanol, right from alcohol, is a VOC, is a VOC that's measured by TVOCs and you will get a quite high reading if you have been drinking, but it won't actually be bad for you. The alcohol's impact is in what you drank, not what you breathed. So to the extent that it's harmful, it's the amount you drank, not the amount you breathed. But if you had a true TVOC sensor, it would light up and tell you all sorts of bad things were happening. On the other hand, if you had the same amount of acrolean, which is a gas that was banned in World War I but is generated by burning wood, is a lacrimator, you would be gagging on the floor and struggling to get out. So TVOC should never be used for anything. It is not indicative of anything. It can't be calibrated except in a very narrow industrial environment to be useful. So you can amuse yourself by. If you have one of these monitors in your home that measures TVOC, you can amuse yourself by looking at the number and wondering what it is that's triggering it, but it doesn't really mean anything useful. I recommend that people don't even look, because it's not going to tell them anything constructive. We do, however, need to understand more about specific VOCs what's in the environment, how much and how harmful they are, because some are very harmful and some are not harmful at all.

Simon: 27:54

Yeah, and you mentioned formaldehyde being one. I think probably one of the reasons it is of such interest is it's so ubiquitous in both construction and the products that we bring into our homes. Right, it's everywhere, it's everywhere.

Max: 28:12

And it used to be far worse. It's a very useful chemical in the construction and products world. It makes things easier. It's a good solvent. It works in adhesives so it was used everywhere and until we found out it was really quite bad for you. Concentrations were quite high. Then there are standards about lowering them, about how much formaldehyde products commit. It's getting better and better all the time, but still, if we look today, it's probably the most significant VOC in the population as a whole.

Simon: 28:46

And I think manufacturers of sensors, I think, do recognize some of the limitations some more than others, I'd have to say and certainly the manufacturers of the products that we find in our homes. I mean, I've got one up there measuring TVOCs, amongst other things. You're right, it is amusing, I can see when I've cooked, for example, on the thing. But I have that context. I know I can make that link, that that spike at dinner time was probably the VOCs that were released when I was cooking. I might be wrong, but it's a reasonable guess because I have the context. I think manufacturers would argue, though, that they do provide some information about events, and if you're interested in frequency and severity of events, there might be some. I mean, could you still man that argument on their behalf? Do you think Could you make a case for event monitoring with TVOCs?

Max: 30:00

Well, you certainly could monitor an event, but if and if you only have one kind of event in a particular space, that might actually be useful. But if there are different kinds of events that happen, what is it going to tell you? And has it gonna tell you when that event is something you need to do something about or not? So it takes a quite a bit of sophistication, therefore, to interpret what this is. If TVOC sensor turns red, should you run screaming from your home because there's something horrible happening? Or should you say honey, you forgot to put the top on the vodka. But so I don't like having information that you don't know what to do with. That seems not to be a positive thing, but you know, for people who understand that it doesn't necessarily mean anything, it's, it's fine. I have a I have a room air cleaner that has a TV oc Sensor in it, and sometimes it turns orange and red and I'm always curious as to. Well, I wonder what made it do that. But I don't run screaming from the home because I don't think it's telling me anything useful.

Simon: 31:15

Yeah, and equally, you know a lot of what we're talking about with air quality in the home. We're talking about chronic exposure to, and that often isn't event-based. That's the, the, the, the general level of pollutant that you're exposed to over the longer term. And Certainly at those devices and similarly with the PM I'm monitoring at the low cost end, they tend to be Less accurate, the lower levels of something that you're monitoring, just by the nature of their plus or minus Accuracy of the device. You know, if you're trying to measure 10 micrograms of particulates, for example, a low-cost sensor isn't necessarily very good at doing that. It will tell you that you've got a big spike of 60 or 70 because you've there's a dumpster fire outside, but it isn't necessarily going to tell you going back to one of your original points of these Thresholds that are set by, say, who, that your, your home, is under a WHO threshold for particulates or VOCs.

Max: 32:19

You know, I think that's the challenge of them, I think, set sensors are getting better every day and Particular sensors may be getting in the range where low-cost ones are reasonably Useful, so I'm optimistic there. The most significant event that happens in a home is cooking. We don't need a TV OC sensor to tell us us that it's the most significant generator of Reactive compounds and of particles, and this is why it's really important to have a good range hood or a cooker hood Over your stove, because there's lots of nasty stuff that it happens, and if you have one, it really doesn't matter that much whether you cook with gas or electricity, because you're venting the Products of combustion just like you are the products of cooking, and so that's kind of a second-order Effect about the, the NO2 that that's generated from cooking. As long as you have a hood that you operate and that's how you handle events it's is by having some mechanism like exhaust ventilation that can extract the nasty stuff when you, when you generate it. Another reason why the TV O sensors aren't going to be all that useful.

Simon: 33:39

Yeah, and change will come, particularly in a residential setting, from habits that are formed. Rather than Reacting to a little sensor going orange on the wall, I guess that that that a habit is formed to turn on a local exhaust system when you cook. You know that's a behavior thing more than a, a measurement and an automation necessarily.

Max: 34:03

It's true, although with a decent, low-cost sensor, it wouldn't be hard at all to have an automated hood that just comes on when it should. I'm I'm A big proponent of having systems that that are smart enough to do a reasonable thing when it's necessary, rather than to have to force changes in behavior. That always seems a tough thing to do.

Simon: 34:25

Yeah, fair enough, and I won't go too much into cookie hoods because I do plan to chat to both Ben Jones and Ian Walker at some point and they are Mr and Mrs burnt toast. I'm not saying who's Mr or Mrs, but I think it'd be. I don't want to steal their thunder on that one, but. But on particulates I think. Could particulates be analogous to TV OCs, in the sense that we talk about Particulates as if it's one thing, in the same way that to TV OCs are trying to apply a number To one thing. And for example, that little cheap Particulate sensor up in my room there is giving me a 2.5 Reading. So for listeners that's very fine. Particles that are particularly Interesting to us because we have the ability to breathe them deep into our lungs. But it's not just measuring 2.5. It's having to make some assumptions. It's, it's, it's. It's adding up all of the particulates up to that level. It doesn't differentiate between one type of particulate and another and one would assume there are lots of different types of Particulate. Some would cause us harm, some may not.

Max: 35:50

Well, there's a little certainly a little bit of truth in what you said. Pm 2.5 is not a single thing there there. There are Some pieces of it, but they're far more closely related than ethanol is to acrolean or something. So it's it's a matter of degree. It's also a matter of Time, that is, we didn't used to be able to measure PM 2.5 real well. We can only measure PM 10. So a lot of the standards that we have of the earliest standards are based on PM 10, which means 10 micron particles are smaller and and 10 micron particles can include things like pollen and and dirt and Between sort of 2.5 and 10. Those particles can settle on the ground. They're big enough. The 2.5 particles don't settle too well and, as you said before, they also travel much deeper into the lung. So we base our studies right now on the physical properties of these particles, that is, they're just a lump of Of stuff that irritate your lung and cause respiratory disease. There is also a chance of the chemical nature of what these particles are could could matter that that you know, things of organic matter might be different from things of black carbon. That is something that's being studied and if we learn enough, then we'll perhaps be able to differentiate a purely liquid Part which probably doesn't have much physical attribution because it just becomes part of the surface layer that it, that it touches, and that's how it delivers the medicine in your inhaler so quickly, because it just it goes right in. But Minerals may be very different, metals may be different. All of these things are being studied and there's also the open question about even smaller particles. Pm1 those below is one micron May be able, may be worse, because they can actually penetrate In in deeper and there are many indications that that they're more significant than the one to 2.5. So these studies may all mean that down the road we're going to have more differentiated standards. Right now, pm 2.5 is pretty good at what we have and you're right. Some sensors are Calibrated to read in PM 2.5, assuming a certain size distribution, because Depending on what the sensor is, it may only count particles. It may be able to size differentiate. It may not be. All of these things are in the sensors themselves and they're getting better all the time, better and cheaper, and presumably that will continue and we'll be able to use them to find out more and more.

Simon: 38:44

Yeah, really interesting.

Max: 38:46

I talked about Unintended consequences, which I think is always important, the when I was the first one I had like. That which I still remember was that they started insulating the attics of homes in the 70s right these. These were in the north part of the US, it's quite cold and quite a lot of energy and and they insulated the addicts. And you know, the first winter the energy use went way down. They were very happy. Come spring there were Giant ice balls crashing through the ceilings of people's homes and and the reason for this, as it turns out, was that the stoves Were not homes and stoves were not ventilated Outdoors. They were ventilated into the addicts and the addicts were kept warm enough by the house that it didn't condense anywhere. It just ventilated outside. But when you insulated them, the addicts got cold and the ice built up on the Underside of the roof all winter long until sun. You know, got warm enough in the spring that they just you fell off and right through people's roots. Wow. So you know that's a pretty good example of you have to look at the building as a system and figure out everything, what all the interactions are gonna be, not just the one thing.

Simon: 40:17

Do you think we'll make those kinds of mistakes going for? I mean, because they're quite elementary building physics mistakes and you know, I get the sense. We do know how to build a good building at this stage and we do know how to renovate buildings effectively. I'm not saying that's done regularly, but we do theoretically know what we're doing at this stage.

Max: 40:41

So those kind of big unintended consequence mistakes you'd hope are a thing of the past, you know in the broad scheme of things, it's true, but in every age we have made these mistakes, and the most serious ones always involve moisture, and so there were a lot of buildings like built or retrofitted in the hot, human parts of the US that wound up rotting because they didn't understand how the moisture was moving in that building before and they messed it up unknowingly by doing energy intensive retrofits. In Seattle, they faced a disaster where they copied home building that we use here in California and had been using successfully for 20 years, and even in they were highly energy efficient homes, but it rains a lot more in Seattle than it does here, and it turned out that mattered because there were the small amount of leaks, but there wasn't enough drying potential in Seattle to get rid of them and moisture build up and after a few years things rod. So I think we should expect to continue to make mistakes, and we can hope that they get smaller and smaller as time goes by, as we learn more and more about what to do and what not to do.

Simon: 42:08

And that's very hard to do in a construction environment where everything's small margins and race to the bottom and minimum standards based. You know, if you had a culture of innovation and learning from mistakes and post challenge reviews of performance, then you know I think you'd move forward a lot quicker. But what we tend to find is mistakes are covered up, the changes are obfuscated and kicked down the road for periods of time that industry struggles to change because it thinks it's gonna affect the bottom line. Innovation is very hard to do in that sense, and particularly with moisture risk. You know it is so specific depending on where you are, and the drivers of moisture balance in a building can be so strong in certain areas. You know, talking to colleagues in the tropics, they have exactly the opposite building physics going on than we have in Northern Europe, where you have very high vapor pressure loads outside and conditioned dry spaces inside, and in Northern Europe we've got incredibly high vapor loaded spaces inside and very cold, dry outside. You have to have completely different building fabric makeups and your approaches to renovation can be completely different and often you're dealing with buildings that were designed to manage that from a century ago and now we start tinkering with them and we're moving interstitial condensation points around solid walls and timber structures and it's a whole other area. We haven't talked about it today, but moisture balance in buildings certainly is one of the frontiers I think that we have to address, particularly in renovation.

Max: 43:58

Yeah, that's right, and of course we face the same thing in the Southeast of the US that those Asian climates face, because it's quite hot and humid in Florida. Yeah, so they've run into a lot of those kinds of problems, and regulation makes it worse. But there's a group called EBA Energy Efficient Building Association, and this is the group of forward-looking, innovative builders who try to be on the leading edge and work to solve these problems. You're right that the majority of builders aren't there. They are, as you said. They bid for a building. They want to make it as cheaply as possible, they want to make their money and move on. But the Energy Efficient people, they can tell us what's going to go right and wrong in the future, and so Ian Walker knows a lot about that. You can talk to him.

Simon: 44:52

Yeah, brilliant, Thanks Max.