Air Quality Matters
Air Quality Matters inside our buildings and out.
This Podcast is about Indoor Air Quality, Outdoor Air Quality, Ventilation, and Health in our homes, workplaces, and education settings.
And we already have many of the tools we need to make a difference.
The conversations we have and how we share this knowledge is the key to our success.
We speak with the leaders at the heart of this sector about them and their work, innovation and where this is all going.
Air quality is the single most significant environmental risk we face to our health and wellbeing, and its impacts on us, our friends, our families, and society are profound.
From housing to the workplace, education to healthcare, the quality of the air we breathe matters.
Air Quality Matters
Air Quality Matters
#42 - Gaëlle GUYOT: Smart Systems, Energy Efficiency, and Indoor Air Quality Innovations
Could your home's ventilation system be smarter and more efficient?
Join us as we host Gaëlle Guyot from CEREMA to explore how smart and demand-controlled ventilation systems are revolutionizing the built environment.
Gaëlle unveils the core principles of these adaptive systems, which respond to real-time building needs, occupancy, and environmental conditions, optimizing energy consumption while maintaining top-notch indoor air quality. Say goodbye to outdated fixed-rate ventilation and hello to a future of energy-efficient, adaptable indoor climates.
We look into the complexities of humidity-based ventilation, especially France's unique approach to balancing energy efficiency with indoor air quality. Gaëlle's provides an insider's perspective on national agreement procedures, the use of CO2 and humidity indicators, and the historical evolution of these systems. The discussion spans the application of these innovations in countries lacking indoor air quality standards and the tools used to validate their effectiveness, presenting a comprehensive view of how these systems have been refined.
Finally, we explore the latest advancements in air quality measurement technology and the durability of smart ventilation systems. From the significant improvements in sensor technology to the ongoing need for research on long-term robustness,
She highlights both the progress and the challenges ahead. We also emphasize the importance of regular inspections and maintenance, and how organizations like CEREMA play a critical role in advancing building performance and sustainability.
Gaëlle GUYOT - Linkedin
Cerema
AIVC
Annex 86
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Welcome back to the Air Quality Matters podcast. I believe we already have the tools and knowledge we need to make a difference in our built environment. The conversations we have and how we share what we know is the key to our success. I'm Simon Jones and this is episode 42. Coming up a conversation with Gael Gale. In this episode, we discuss smart and demand-controlled ventilation, the long-term performance of ventilation in the field, and the work of Gail and her colleagues at CEREMA, a prolific organisation in the field of air quality and ventilation in France.
Simon:Since 2006, gail has been interested in the complexity of the interactions between the different air flows in buildings and their impact on energy, comfort and indoor air quality. At CEREMA, she is involved in scientific projects that make it possible to remove obstacles in order to anticipate and support the evolution of regulations in France and Europe for buildings that meet the challenges of climate change and public health. The improvement of the quality of ventilation and air tightness of buildings, the development of methods to assess the performance of ventilation at the stage of design, the sustainability of performance and the development and promotion of promising strategies such as smart ventilation are crucial subjects which she is working on. She is the co-author of about 60 articles in international journals and conferences and has been a member of the scientific committee of the air infiltration and ventilation center, the aivc international conferences, since 2018, and has represented france on the aivc board since 2022. I have known gail for over a decade and admire her work enormously, and the quality and quantity of output from her and her colleagues at CEREMA is astonishing. We both have an interest and passion for demand control ventilation systems, so I was really looking forward to this one.
Simon:It took us some time to get this one together, but I hope it's been worth the wait for you. Thanks for listening. As always, do check out the sponsors in the show notes and at airqualitymattersnet. This is a conversation with Gail Gail. One of the things we see is this natural tension in the built environment between trying to save energy, make our buildings more energy efficient and also provide good ventilation, adequate air quality, and one of the solutions that's often talked about as being a potential remedy to that tension is smart ventilation or demand control ventilation systems. What, to you, does demand control ventilation mean, or smart ventilation?
Gaëlle :that's true, that, um, I don't know in in the uk, but in france, when we talk about smart things or smart buildings and so on, it has been connected to the presence of sensors or of IoT, of smartphones connected or something like that. And finally, this is not the definition of smart ventilation that we decided to use, I would say, in the IVC community or maybe in the research world and even on the field, because for us, smart ventilation is really a ventilation which is not dump. The colleagues of LBNL had a report entitled yeah, something I don't have the exact title, but it is yeah, without smart ventilation, building or dump or something like that.
Simon:Yeah.
Gaëlle :And I like this definition because, yeah, we don't leave the light on when we leave a room, and this is quite the same with ventilation. In a sense, I would say leaving the ventilation completely on during a long period when the building is not occupied, for instance, it's something damp or something that we would like to avoid in this international context.
Gaëlle :So, yes, this is a first, very short definition. Smart ventilation is a ventilation which is not dump, but if we want to go further, so the idea, if we go back to the definition of the IVC, is to be able to adapt the ventilation system and so the air flows to the real needs of the building, of the occupants, and to adjust the air flows depending on the needs. And it could be in time, so during the day, for instance, in schools, we don't have the same needs during all day, or in the residential buildings as well, but in location as well. So, for instance, in one room we could have a shower and now we have a high need of air flows, but in a bedroom, where we won't be during one day, we won't have the same need. So, yeah, the idea is that ventilate with the same airflow rates every um, everywhere, every day, is not a good idea. This is not very smart. So the smart ventilation will adjust the air flows. This is, I think, a definition more precise.
Simon:That's a good one. Yeah, I can't remember what the saying is, but I think it's a stuck clock is right twice a day and there's a little bit of that with dumb ventilation, I think. Or fixed rate ventilation systems. We're trying to pitch a guess as to what we think ventilation rates should be based on all sorts of broad assumptions of the building type and the number of people and how airtight it might be or what pollutants people might be generating. And that guess, by the nature of buildings, is constantly changing. The need for ventilation in a space is always going to change. So if you have a fixed approach might be right occasionally, but it's probably going to be wrong more often than not. So I guess that fundamentally, rather than ai or connected devices or some cloud computer, smart ventilation is really describing that ability to adapt to a need. Is that effectively what you're saying?
Gaëlle :Yes, yes, exactly. But finally, what we could, yes, what we consider, is that smart ventilation is something very. It's a very large definition which could include a very wide range of systems. The idea is just not to ventilate with the same airflow all day long, because I talk about the occupant needs. It could be other points, like the, the electricity grid demand, for instance. It could be a high level of outdoor pollution as well. It could be, yes, very. We could think about many, many points which had to be taken into account if we want to ventilate, to consume less energy and ventilate in a more efficient way, more efficient way, and so and the demand control ventilation is a subset of smart ventilation.
Simon:So this is a, yes, a category of smart ventilation, but we could think about more many other types of ventilation yeah, so so for us to be clear, then, when we talk about demand control, ventilation, in your mind are we talking about something that's separate to, or within a sub category of, effectively, this large umbrella of smart ventilation systems?
Gaëlle :yes, exactly, demand control ventilation. Oh, I don't have the exact definition, but this is a ventilation where we have some sensors and that we could, in real time, adapt the air flows. It could be electric sensors, it could be sensor accutor, like we have in France on the humidity-based ventilation. It could be several types of sensors, but in a way we need to sense some EHU parameters in order to have an estimation of the needs and to adapt the airflow. So, yes, this is the demand control ventilation.
Simon:And then the kind of definition for smart ventilation just expands that out even further that you're making choices that might not just be to do with air quality, you might. It might be to do with external environmental conditions, electric grid usage, predictability of use of the building.
Gaëlle :All sorts of things could come into play under that broader definition and, moreover, it could be very simple strategies like turning off the ventilation system for long unoccupied periods, with in but make sure before that occupants come back to have, like, a purge of the building, so to have a high level of ventilation. But, yes, it could be very simple strategies as well, like just turn off when we think it's good to turn off the ventilation systems.
Simon:regarding all the parameters that we have to face, and you mentioned that in ventilation systems like you have in France, France has been certainly has looked at demand control ventilation for a very long time, hasn't it? It's something that it's well understood, particularly in the residential sector.
Gaëlle :Yes, that's true, I think. I don't want to say mistakes, but I think France and Belgium have been the two countries where smart ventilation, or at least demand control ventilation, has been used for a long time, I would say in the beginning of the 80s, because, I think because we had industrial manufacturers in those countries developing such strategies. So in France, indeed, it was the humidity-based ventilation systems which have been allowed in the regulation, in 83 already, and then since 1983, we could say that nearly more than 80% of the residential stock, so single-family houses, but as well the multifamily buildings, they have been equipped with humidity-based ventilation. So, yes, we have like 50 years of feedback on that.
Simon:Yeah, that's pretty impressive and it was humidity based and I think you you pointed to something salient earlier and that was that we have to have that. We would assume that it requires sensors to measure something. So I'm guessing, back that far back, we weren't looking at electronic voc sensors and particulate matter sensors and things like that in our built environment, humidity was probably one of the first things that we could measure um effectively. So I'm guessing that's why humidity was one of the drivers, and obviously moisture being a major challenge in the built environment as well, particularly in homes.
Gaëlle :Yes, I think it was part of the reason.
Gaëlle :The reason sorry, I think it was as well due to big issues in the building sector regarding moisture and more than moisture mold problems in buildings, more than moisture mold problems in buildings.
Gaëlle :After the oil crisis at the beginning of the 70s, we had big retrofit programs, notably in social housing, and so we changed the windows with airtight windows, we changed the envelope with external or internal insulation and so on, and despite the fact that we had natural ventilation due to vertical chimneys I don't know the English word exactly, but it was not natural ventilation due to the opening of windows it was a design ventilation system which was installed in nearly all the multifamily buildings stocked in France.
Gaëlle :So, despite this, as we didn't allow the air to enter in the bedrooms notably, we had big mold problems we had many pictures with very impressive problems due to mold and I think that we had a big concern, a high concern in France, concerning the humidity management. So I think it's many reasons who pushed toward this system, and one other reason was the discovery of these two industrial manufacturers regarding this sensitive material used in this air terminal device the extract, the exhaust devices and the trickle vents. So they discovered this material At this time, they had the idea to use it in the ventilation. And, yeah, this context, I think this is a context, a global context.
Simon:Yeah, that's really it. I mean, with what you were saying there, gail, you could you could almost imagine you were talking about a problem, now that we were. We had a fuel crisis, there was large-scale retrofit and we discovered that we had problems with condensation, damp and mold as a result of underventilating. It's as almost as if, uh, history is repeating itself to some degree. Um, so I think that's fascinating.
Simon:Um, I think the word that you were searching for is passive stack ventilation. I think we would describe it in english in in that terms, where you would have risers or columns within a building that used the chimney effect effectively to pull air up from the wet spaces, and it was the uncontrollability of that that this type of system was answering the question for. To give listeners a little bit of context, my previous life I worked for one of those french manufacturers, so I perhaps have a little bit more insider knowledge than most interviewers on demand control ventilation, but I think it's a fascinating history. Um, both, because that's just frightening to me that we're having the same conversations in 2024 about the importance of ventilating when we're retrofitting buildings, um, that we were having in the late 70s, early 80s, so it's not as if the.
Gaëlle :The lessons aren't there for us to look back at yes, and and coming back to this, to how those work these systems in France, because sometimes we talk about other professionals in other countries and the systems are very, very different in the different countries. It's not only based on humidity. When you compare a humidity-based ventilation system in different countries in the world, you will have a very wide range of systems, and so the one we have used for a long time in France is able to ventilate more than the nominal airflow when and where we have a high demand, a high need, so a high level of humidity, and is able to ventilate at a very low airflow when we don't have any needs. So this allows a wide range of air flows as well, where, in some countries, you just have the nominal airflow and when you sense you have some sensors, you can have the nominal airflow, and when you you sense you have some senses, you can decrease the airflow, but you can never increase it.
Simon:So this is a big difference that's interesting, yes, and and it's also the other way around in some countries, some countries will insist on always having a nominal airflow and only allowing some adaptability above that minimum rate. So it's interesting, isn't it, how different jurisdictions perspective on what's important, and I guess that's. I guess that's driven largely by either energy or air quality. If you, if you won't allow it to go below a nominal, maybe your fear is the air quality side of things, that allowing the system to reduce below that rate might carry some risks, and I guess, if you're very fearful of energy use, over energy use, you might not allow it to go above the nominal. Um, that's that's interesting, isn't it that?
Gaëlle :so, yes, you talk about the balance between energy and indoor air quality or indoor environmental quality. So what, yes, what pushed to the installation and implementation of this system in France? That's true, that is the energy, because, thanks to this system in France, that's true, that is the energy, because, thanks to this system, the energy savings are around 30% or even 40%. It's a range, but they secure since the beginning, they secure that it would be in a way, it will be done in a way that's without compromising the indoor air quality. And so, in order to reach this target what they do in France they decided to give an agreement to these systems, yes, to give an agreement to these systems. And in order to obtain the agreement, the industrial manufacturers have to go through an agreement procedure and to proceed to a calculation energy-based calculation, but as well with indoor air quality parameters. Proceed to a calculation energy-based calculation, but as well with indoor air quality parameters and indicators. So this is not perfect, but they have been using CO2-based indicators and humidity-based indicators in this procedure.
Simon:So, yes, yeah, that's interesting. Interesting, isn't it? Because I suppose one thing that's interesting for people to get their head around is that, effectively, with demand-based systems, you're allowing a ventilation system to make a decision on how much air a building is going to have, and there are obviously consequences of that, both in energy and in, potentially, air quality, depending on whether you're going to go higher or lower than perhaps that national government has decided. Is the safe number, let's say? Is the safe number, let's say, and in the early days this must have been very early from a modeling perspective, being able to apply this to big CONTAM simulations and things like that. So back in the 80s and early 90s, how did they determine that these variable flow rates were either safe or presented this much of an energy saving? Was that done practically through tests in real houses and things? Was that how it was done?
Gaëlle :No, they used a national tool which is like Kantam. I would say it was developed especially for the French context and, yes, it's a flow, it's a pressure code, so the equations are the same than in Kantam or tools like that, and they have a list of geometries. So, like I cannot remember how many, but maybe 20 geometries they had, we have single family house, we have apartments, and those geometries have have been developed during all the time. I I mean, for instance, at the beginning we had only one-level single-family houses and then we discovered that sometimes we have a problem with one-level houses, so we added a new geometry in this list. So, yes, this is not a fixed list, but we had this list of geometries and then they had to do the airflow calculation and the indoor air quality calculation in order to show that the selected indoor air quality indicators were complying with the thresholds.
Simon:Interesting, and from my understanding as well, that, depending on when in time countries have looked at this and how much history there is behind it, you I mean in the early days well, even today we don't have a lot of indoor air quality standards or thresholds to benchmark against. So in that context I think there's this equivalency approach isn't there with some of these demand systems, where you say well, am I providing the same type of air quality as the fixed version of that ventilation system? So rather than saying I'm going to keep air quality below a certain number, I can say that as long as I'm no worse than an existing system out there, then that's the way of kind of passing, if you like, the efficacy of that system. It's quite common. I don't know if I've explained that very well, but for listeners the challenge with demand-based systems is most countries don't even have basic standards for indoor air quality, so it's very difficult to say a system meets something if it doesn't exist. So there has to be an equivalency approach somehow, doesn't there?
Gaëlle :Yeah, I would say even that in some countries even mechanical ventilation is not compulsory in all buildings. We were working with New Zealand colleagues, for instance or even in Brazil or in different partners. They tell us that already having in the 80s a regulation requiring mechanical ventilation in all the residential buildings is a big step for them in 2024.
Simon:Yeah.
Gaëlle :But coming back to your question, yeah, so in France we didn't have this equivalent approach, because today we are having a national program on that.
Gaëlle :It's my colleague, valérie Leprince, who is in charge, and we tried, with Valérie, to go back to how they defined in the early 80s these thresholds for humidity-based ventilation.
Gaëlle :Only Did they manage some yes, some simulation with the basic constant airflow ventilation system and so on. So we didn't get the answer, but we think that, no, we don't know exactly how they decided these thresholds, but absolutely it was not the equivalent approach. But absolutely it was not the equivalent approach. So, yeah, we don't have the answer, but now we are trying to develop an equivalent approach for allowing many types of innovative systems and not only the humidity-based ones in France, and so we are trying to find, to assess the performance of all the humidity-based ventilation and even all the type of ventilation which are used today in France, and we can say that we observe different reasons. So we know that they are not equivalent at all, but this is what they do. Yes, in the ASHRAE 62.2, for instance, which has been in use for maybe 10 years now, with the smart ventilation section inside. But, yes, this is not the approach we had in France.
Simon:Until then I I would say until today yeah, and today I I'm guessing it must be much more complicated than it was previously, because not only we have a lot more definition over what we consider adequate air quality, that you know the while standards may not exist, there's good evidence as to what type of thresholds of this, that and the other are important to us, but equally our ability to measure those is more sophisticated and we're finding some of those sensors in that decision making. So there are so many more parameters to think about and all of the logics that go with that. You know what, what thresholds trigger what responses and so on. It's it's a much more complicated picture, I guess, than we were 15, 20 years ago yes, several aspects are more complicated.
Gaëlle :The first one is that when you have only one reference system, it's really easy to have the reference performance indicators to have a value and so on.
Gaëlle :When you have 50 reference systems, like this is the case today, it's more complicated. Yes, indeed, about what we know about the relevance of indoor air quality indicators, I would say that we don't have the answer today of what is the more relevant EAQ performance indicator, and there is a difference between what you fix like a performance level for a system and what you can measure. I mean, for instance, you can, you can allow some ventilation systems using, I don't know, like voc detection. They do, they do that in Belgium for the toilets. Even if you are not able to precisely model what is a VOC emission in the toilet and how it will react during your simulation phase and what will be the results of performance based on VOC. Because this is not, you can have some sensors which are very useful to reach performance, even if you cannot really model the performance, neither measure the performance. I don't know if I am very clear. I think sometimes you cannot model some phenomena, physical phenomena, but it doesn't mean that you don't have to model them because they are important.
Simon:Yeah, and I think I get what you mean. But also I think there's a difference between being precise in a number that you read with a sensor and having academic rig over over something. So you know, vocs is a good example. Academics tend to run around with their hair on fire every time someone mentions total volatile organic compounds because it's for most people involved in air chemistry. It's a worse than useless number for them, really, that it tells them absolutely nothing.
Simon:Yeah, but from the perspective of reacting in a space to an event, if you can be fairly sure that it will generate a range of vocs that can trigger a ventilation system to react, do you care that? The challenge then comes in modeling or measuring its effectiveness? It may react and react the way you want it to, and what we mean by that is speed up or slow down or move more air or less air because of a presence of a voc. The challenge comes in demonstrating efficacy, I guess, because you're not really sure what the you have to define, what good is in order to to define efficacy, and that that's harder to do with some of the. The tools and vocs is probably a more complicated example, but no not really, because when you talk about it's nearly the same idea.
Gaëlle :For some chemists it's an aberration to talk about PM without PM 2.5, without talking about a dispersion with a granulometry of all the size of particles and so on. So this is, I think, the same for particle matrix. Yeah, but so you tell it better than me.
Simon:Thank you, simon it was exactly what I had in mind. Well, I think what fascinates me about demand-based ventilation systems is they they come up against this that the confluence of academic rigor and understanding and what what we understand as accurate or measurable or of value from a scientific perspective, and actually getting a good outcome, regardless of how well we can measure it the reality of being in the real world and again, I'm not sure if I'm explaining that concept well enough, but I think what's interesting is that, ultimately, what we care about is getting better outcomes in our built environment and whether or not the particulate matter measurement is accurate to within plus or minus 10 percent, or is really reading 12 micrograms when it should be reading 20 or something. Does it really matter if what you get out the other side is better ventilation and better air quality? And I think that's the interesting thing where you get that? The innovation and engineering of sensors and demand-based ventilation systems and the rigor and academic oversight on thresholds and all of that kind of stuff, how those two butt up against each other yeah yeah exactly it's where science meets the real world, in a way you know,
Gaëlle :yeah, it's fascinating, yes, and in some senses they could be used to detect an event. So, yeah, we talk about the, the toilets, but in the kitchen as well, we, we, if we have not very. We had a national project in france as well. It was not in ceramide, was by satiate colleagues, but they tested the accuracy of particular metal sensors, and so the answer was the response was not very accurate, was not accurate enough to I don't know to really assess the health impact, for instance, but they were accurate enough to detect a cooking event or something who revealed that we need to ventilate more. So, yes, in that condition to ventilate more. So, yes, in that condition. I really think that we have to not to be as narrow-minded in the scientific world. I would say, and to yes, and to be close to the reality and to the field. In fact.
Gaëlle :Such sensors that could be very relevant to make a very high level of energy reduction without compromising indoor air quality, so that's a good solution, I think just going to grab your attention for a minute.
Simon:I wanted to quickly tell you about lindab, a partner of this podcast. For over 60 years, lindab has been dedicated to improving the climate of buildings. I have known them and some of the great people who work there for as long as I have been in this industry. Lindab offers a broad range of products, from individual components to complete indoor climate solutions. Their systems not only promote better indoor environments, but also deliver economic benefits. If you're working on a new building project, lindab's high air tightness products and demand controlled ventilation systems are designed to meet the stringent energy efficiency requirements of today and align with environmental certifications. If you're renovating, lindab's smart units can upgrade existing systems, reducing energy consumption by up to 70%, with minimal impact on the building structure. Lindab's products meet the certification standards for BREEAM, leed, dgnb and many more, ensuring optimal environmental performance. And if you're looking to simplify your design process, their range of ventilation software and tools make product selection, calculation and performance evaluations quite straightforward. Creating healthy spaces is at the core of Lindab's mission, which is why, at Air Quality Matters, we are so pleased to have them as a partner with this podcast. Do check them out in the podcast notes at airqualitymattersnet and, of course, at lindabie.
Simon:Back to the podcast. Yeah, and I think the great thing about that scientific endeavor is is that its response is to the industry to always try harder, always try and improve the accuracy and measurability of the air quality. I think what the industry brings to that is the commercializability and scalability that enables companies and sensor manufacturers to invest in improving, because without that they wouldn't have the money or the commercial viability to do it. And you must have seen it the same as I have over the last, particularly the last 10 years, as I have over the last, particularly the last 10 years. The scale and speed of improvement of this technology is just astronomical at the moment, um, and we're getting more and more sophisticated in our ability to zero in on these measurements, um, and every two or three years we just seem to be making a great leap.
Simon:I was in the Sensirian factory in Switzerland there a couple of years ago and they've got a great visual demonstration of how the technology has advanced over the last few years. It's quite a famous image. I'll see if I can find it, I'll put it on the show notes. But it's a a series of test tube jars. Have you seen it where they've got their first ever humidity sensor and they look like little spiders. They're like big chips in the first jar and I think they've got like a 50 or 100 of them in a big test tube and it goes right to the top and then every three or five years they show the next version of the temperature and humidity sensor and their latest version. It looks like a bit of dust in the bottom of the last test tube.
Simon:They're so small that these the speed of innovation over that 10 year period is shocking that they can do the same thing with something so tiny and so efficient that now actually their last revision of that sensor can't be produced because there isn't the machinery to place a sensor that small on circuit boards. So they're the. The other side of the industry that puts these uh circuit boards together doesn't actually have the machinery to physically pick these little sensors up and place them because they're just too small. Um, so it's an incredible journey that industry's on, and I was talking to Stanton Wong, who's the president of Reset, and even something like VOCs, which he's been looking at for the last 10 years or so as part of the Reset standard.
Simon:He's saying clever things come across his desk now, where you'll actually have three or four VOC sensors on a board, all calibrated to look at a different spectrum of VOCs, and they work against each other. They're using AI and algorithms to zero in on what the VOC is likely to be. So they're kind of deliberately cross-sensitive, these series of VOC sensors. So the industry is just constantly innovating. So what we think we know now, in a couple of years' time it's probably taken another leap forward.
Gaëlle :Yes, but I think as well that progress has to be made on the durability aspects of these sensors. It's what we observe, that we nearly don't know anything about the durability and the robustness of the sensors that are used in the buildings in general, but especially in the ventilation systems. In the ventilation systems, I think, in general in buildings, we don't know many things about the durability of components, in fact, a lot of things, yeah, quite frighteningly.
Gaëlle :That is, sensors and ventilation components, among a lot of other things. But yes, we look to the literature, to the international studies and so on, and we never, we only found a very, very small number of papers or reports or data about the durability of sensors and ventilation components, and I think that the industrial partners have manufactured. They have really to look to that aspect. Yeah, especially for smart ventilation, because you already have a podcast or an article some days ago about the real performance of ventilation in buildings.
Gaëlle :So we know that, yes, in general, the quality of installed ventilation system is far from the attended quality. We have many, many dysfunctions in general, and so this is a general problem for buildings. But for smart ventilation this is even more a problem, I would say, because when we talk about the variation of air flows, we have low air flows at some times and some places, and higher we are supposed to have lower and higher air flows and higher we are supposed to have lower and higher air flows. But if the system stays blocked at a low air flow, this is a problem. And this is what happens when we don't have a robust census on the long term, or even when I say long term, it 10 years maybe, or even five years, we don't know yeah, that's a really interesting point you make and I I think the evidence is quite clear that there's absolutely benefits to modulating airflow for a range of needs.
Simon:Right, it's just common sense. Like you say, we turn the light on when it gets dark or we want to read a book, or off when we want to go to sleep or we don't have it on during the daytime. Like it's common sense to control lighting based on the need to light a space. In the same breath, it makes sense to modulate ventilation based on a whole range of other needs. So it's no surprise that it can be more energy efficient to turn ventilation off or lower it when you don't need it and increase it to meet the demand when you do need it. I think that's manifestly obvious.
Simon:The the point you're making I think is really interesting is we're absolutely rubbish, even as it stands today, at figuring out how to provide a fixed airflow and the the way problems arise in the built environment is somebody has a problem, either that they feel like there isn't enough ventilation, or there isn't enough ventilation and you have problems with air quality or damp or mold or something like you were describing with in the 70s and 80s in france.
Simon:And then somebody has to go in and figure out what's going on and at least you can measure that fixed flow rate and say, well, look, it's supposed to be x, it's y, this is the gap we need to address. Look, it's supposed to be X, it's Y, this is the gap we need to address. That right, and it's fairly straightforward, doesn't happen in the real world and we find these huge gaps in performance because nobody really maintains systems. We haven't had very good policing and building control over the years. It's a bit of a forgotten building service ventilation in a lot of ways. You add the complexity of not knowing what the flow rate should be when you turn up, because it's variable. That's a whole other ball game.
Gaëlle :A lot because we had a big study about the dysfunction rate of ventilation in single-family dwellings. So we already knew at this time that nearly 50% of the buildings in France were not compliant either with the airing regulation, which is the regulation about ventilation, or with the energy performance regulation. So that means that if we had too high rates we were not complying with the energy performance regulation. So that means that if we had too high rates we were not complying with the energy performance regulation and if we had too low rates airflow rates we were not complying with the airing advantage. So we knew these global statistics but we had a precise study looking to more precisely. In every report that we got that we compiled all the problems, the sources of problems and the dysfunction rate was 68%. So 68% of single family dwellings in France in this national study we had more than thousands of dwellings were not compliant. So this was very, very high.
Gaëlle :And at this time at the national level, the policymakers, they were really open, I would say, to implement a new regulation with an inspection of ventilation systems.
Gaëlle :But the barrier was we were able to measure the air flows for constant air flows, ventilation systems, but they equipped only maximum 10% of the residential buildings.
Gaëlle :So this is not really interesting, really interesting but we are not able to measure the performance at the air terminal devices for more than 90% of the humidity ventilation systems.
Gaëlle :So we had a national research project. It was really about research how are we able, and what are the protocols to be used in order to do this measurement? And so, with this system that we are using in France, we have a range of performance depending on the range of pressure, of difference of pressure that we have inside the duct and in the room, and so, thanks to this measurement I make it very simple but thanks to this measurement it is possible to know if the systems works, comply with the regulation or not. And so, after five years, I would say, of research, we had a national protocol, and so now it's really recent, but two years ago we had this national. In the national energy performance regulation we included a new compulsory inspection for ventilation, and this is possible to have this inspection on the humidity based ventilation, even if we cannot measure directly the air flows. So, yes, I think in all the contexts it could be possible, but it's more complicated indeed.
Simon:Yeah, and for context, that's about the same time that Ireland was introducing its compulsory inspections of ventilation systems as well. How does it work in France? Is it? Every ventilation system of a new build has to be inspected? Is it a percentage, like they do in Belgium? How does it?
Gaëlle :work in France, it's every.
Simon:Every, and is that an independent organization that does those inspections?
Gaëlle :Yes, independent organization with an independent qualification process. We had nearly the same procedure that for air tightness and sometimes they are the same testers who come to do the air tightness test and the ventilation inspection yeah, we've seen the same manifest in Ireland because ultimately they're the people going around in vans with the equipment to do the tests anyway.
Simon:So you know, if it's the same scale of inspections for air tightness as it is ventilation, it enables the two industries to piggyback, although what we have found is that the inspection of ventilation systems here in Ireland tend to happen much later than the air tightness tests of ventilation systems here in ireland tend to happen much later than the air tightness tests, so they're not quite piggybacked. Ventilation tends to be tested right at the end because sometimes you may not be able to until power is turned on to buildings, which can be very end, very late in the day, depending on the particular project. So we find ventilation inspections can be very last minute I don't know, I have not the data.
Gaëlle :I think, uh, if you invite valerie le prince, she will yeah she will tell you all the the details about what she knows about that. But sorry, I don't have the the feedbacks at this time but it is very recent so I'm not sure she already have the feedback.
Simon:But maybe I mean.
Simon:One of the interesting things, um for listeners is something I've been talking about this week actually, funnily enough, has been the, the actual complexity of measuring ventilation systems.
Simon:There's a there can be some misunderstanding of the capabilities of different approaches. I know the ai vc did some presentations on this many years ago, looking at the difference between powered flow hoods and unpowered flow hoods and different approaches, and there's, I think, a bit of a misunderstanding or misalignment in the industry over what's the right thing to do when and and ventilation technology is moving on quite quickly as well. So I think the appropriateness of some of those tests might be lacking. But interestingly, for the systems that you're talking about, the the constant pressure systems, actually the tests are quite simple because it's relatively straightforward to measure pressure differences between ductwork and room side and actually it's quite if you've got confidence that the system performs in a certain way at a certain pressure makes it very easy. But that's only those types of systems. Other demand control systems are going to have perhaps more complex ways of controlling flow rates, so it's not always going to be simple.
Gaëlle :Yeah, that's true.
Simon:Yeah, you've been looking at demand control, ventilation systems and performance systems for quite a long time, girl, haven't you one way or the other? When did you first start seeing and researching these types of systems, do you think?
Gaëlle :Yeah, so I started to work with Rémi Carrier in 2006. During this time, we were focusing on airtightness a lot, because we had this big market transformation in France and then we had quite airtight buildings or we were on the way, and so we had like alerts about the high rate of dysfunction. So we started working a lot of ventilation. But, yes, humidity-based ventilation were like a reference system in France. So we were working on that among all the ventilation issues and it was not really clear in my mind that it was a special system, an efficient system and so on. It was just okay, that's like that. And when I was invited in the Berkeley lab with Ian Wolk and Max Sherman, the topic of my stay there was smart ventilation. So, but it was not clear that humidity-based ventilation, it was not clear to me that humidity-based ventilation could be a smart ventilation. You know I am French, so it was just okay, the French ventilation. Why would it be smart? I don't know. No, but it's really. It's really, yes, funny looking back to this time. And so, yes, we started, and at this time, so it was in 2016. So we were. So I think LBNL published maybe, yes, two or three reports at this time on smart ventilation reports at this time on smart ventilation, but we were not using so much this term in Europe or even in the IVC community. It was not really.
Gaëlle :We used human-controlled ventilation, talking about efficient ventilation, and so, yes, after that, when I was there, it was, we were working with Aereco as well and, yes, I realized that French humidity-based ventilation was quite an interesting system. Yeah, I think it's an interesting system as well because we have long-term feedback now. So at the beginning I think they had doubts and we could have doubt everything. We use a new innovative system because you said, between the within, between the theory the theory that we are not always able to do in a more accurate way and between the practice, there is a big gap and sometimes it's not easy to know to assess the real performance of solutions. So, yeah, I think it was a good solution because we had this feedback, this long feedback, and we knew that we didn't have problems at a large scale on the French building stock. So for me it's one of the most reliable feedbacks to show that the solution is robust.
Simon:Yeah, yeah, yeah, and it's, you know, I think, one of the interesting things and it goes back to sometimes we overcomplicate things, but in many circumstances pollutants keep bad company. So just because you're measuring one doesn't mean it's not a good way of covering your bases with many other pollutants. And one of the interesting things that's always struck me about moisture-based sensors is that we're also covering off one of the the factors that damages buildings as well, you know. So it has a very precise control over one of the major risks we face in the built environment, which is moisture imbalance, condensation risk and so on. So, as you'd expect, these humidity-based systems can be very good at limiting some of the problems we see with damp and mold yes, you're right, simon, and but in many discussions we are with researchers, humidity is forgotten.
Gaëlle :Why? Because there is not a real, a direct link I mean a dose response law between humidity and health, or even between humidity and comfort aspects. So humidity, I think, is really one of the most problematic pollutants. Even some persons don't want to name it a pollutant. So you have direct effect on health, you have direct effect on building damages and in some countries where they have high humidity problems in buildings, like in New Zealand for instance, they have one of the worst rates of children's asthma. They have a very high rate of health problems that don't exist in other developed countries and this is due to humidity. They know that the high rate of humidity in buildings causes all these problems.
Gaëlle :So, yes, I think humidity is quite a good parameter. That's true that it's not the only one, but this is one that we can measure quite easily. We can measure it For modeling. We know the emission rates quite easily. We can measure it For modeling. We know the emission rates quite well for metabolic humidity production, but as well for activities like cooking, washing clothes, clothes washing and drying, like all the important activities which emit humidity in buildings, and we are able to quite accurately model humidity in buildings. We have quite a wide range of works for several decades on humidity modeling in buildings. So, yes, humidity is quite an interesting parameter for smart ventilation and for EQ performance in general. I would say and we know that, contrary to formaldehyde, for instance, formaldehyde maybe one day it will be replaced by another pollutant because it could be removed and it could be replaced Humidity. We know that we cannot replace humidity. We will always have humidity in residential buildings.
Simon:So and I and I think that's one of the one of the things about demand controlled or smart ventilation systems is and I was saying this, uh, the other day actually that I think what's interesting about viewing ventilation through the lens of demand is that it forces you to ask the what next questions. It forces what about ism and systems thinking, because if you've decided to measure one thing, you have to answer those questions. You have to think, well, what about co2? Or well, what? What about measuring vocs? What? Well, what about measuring VOCs? What happens in this circumstance? Am I going to cover this? It makes you systems think your way through, I think, to a better solution, assuming you do it the right, assuming you do it with good intent.
Simon:The trouble with fixed systems is you just tend to, because it's such a blunt instrument, you just kind of say, well, that's the standard, we just aim to hit that and I don't have to think too much about the consequences, whereas most jurisdictions that are seriously thinking about demand control ventilation. It forces the issue to systems think your way through the process, which is kind of a bit of the work you've been doing with annex 86, isn't? It is that kind of next evolution of okay, what is smart ventilation? What are reliable measurements in 2024? How do we link that to energy grids and health and all of these kind of things? It's that. It's that evolution and systems thinking of an approach to say, well, okay, if if we're going to match something to something, what are the consequences of it? What are the benefits, what are the unintended consequences? So it's a much more sophisticated conversation than just taking some broad assumptions and saying, look, we think this is our best bet.
Gaëlle :You know we'll hit that rate yes, in the annex 86, we we try to to think about what are the good um, the best, the best um, performance indicators, including health-based indicators. Then we talk about how to take into account the emission rates, the occupancy patterns as well, because as long as we talk about demand-controlled ventilation or smart ventilation in general, we need to have some ideas about where are the needs, where are the occupants. So, yes, we try to work on that and then in the subtask that I am leading with Jakub Kolarik, we are trying to implement all these issues in the process of assessing the performance of smart ventilation. We have several issues. In fact, we try to. I think at the end, because it's nearly the end of the annex it's more about the methodology, how to assess the preferences, because we have yes, I detailed an approach. We have in France, but, yes, in the ASHRAE 62.2, it's another approach with the equivalence principle. We have other standards in Europe, some standards, not a lot, but in the Netherlands, for instance, they have a standard which is using other assumptions and in Belgium, for a while they have been using.
Gaëlle :There is Ireland as well. You talk about Ireland, spain. So in some countries they are using different approaches. So the idea was to talk about the different approaches and to try to find a consensus about what could be the best one. I would say yeah, but it's a challenge. I don't think we answered all the questions, but I think, yes, it's a step forward and we will see later on what will happen. But yes, we had a consensus about the indicators to be used, about some assumptions, but we were more on the modeling approach, more on the yes, how I talk about the French agreement. Yes, how I talk about the French agreement. So yes, in general, when we allow smart ventilation somewhere, what would be the conditions to do that in a way to maintain good health and EQ conditions in the building?
Simon:Yeah.
Gaëlle :So this is not very easy to have an international consensus on that issues, I think it's interesting that that conversation is happening.
Simon:At the same time there's a lot of efforts internationally to reach agreements on having an indoor air quality standard that we might be slowly moving to a point where, again very difficult to get international consensus and depending on where you are in the world, some of those standards could be impossible to reach. But at least that conversation is happening about. Okay, if we're going to have a particular matter 2.5 threshold for an indoor environment what should it be? Um, that makes the conversation and the framing around smart ventilation interesting, doesn't it? Because the the smart ventilation is the next piece. You know, if we can get agreement on what we think good, looks like or acceptable, it makes it easier then for those systems to aim for. That gives them a target.
Gaëlle :Yes, exactly. But what we agree it's the equivalent principle, I would say in general is really to think about what is the performance of the reference system and how to calculate the performance of new, innovative, smart ventilation strategies and to compare these performances with the reference performances. And when we do like that, we don't care about a given threshold for PM concentration, for instance, because we know that there is no consensus as well on that. And I think it's a good way of working on the field, because if we want to open the markets to these systems and we can prove that these systems are saving energy, but maintaining or even sometimes improving the eaq, nobody wants will stop or, yes, make barriers to these systems yeah, and there's two sides to that coin, and I've had this conversation recently.
Simon:There's been some standards coming out of Europe around categories for certain air pollutants and thresholds, co2 being one of them, and we've already seen people starting to make remarks that perhaps existing ventilation systems aren't capable of meeting category one or two or whatever the what would be seen as the good practice or best practice. Um, but there are consequences to that and and I think that's what makes it a much more sophisticated conversation because you're saying well, look, it's fine to have a air quality threshold or something you want to aim for, but that doesn't happen in isolation. There are potential consequences of that, and if you want to, for example, keep co2 in bedrooms below 800 parts per million, you're probably going to have to ventilate quite a bit more than you're doing at the moment, and so there's an unintended consequence from an energy perspective or an investment required to look at things like heat recovery. Um, but at least those conversations are happening, which is really good.
Simon:I think you work for sarima. Uh, how do I say that? Sarima, sarima, sarima. Explain to people what that is, because it's um for somebody that's skirts around it. I I find the output from your organization phenomenal like the, the. The amount of stuff you do is incredible. Is it a government organization or private, or a mixture? What is it exactly?
Gaëlle :so. So serema started to exist in 2014, so I said I started working here in 2006, so before it was a government organization. So we were part of the French Ministry of Ecology or of Housing, I would say, because the name and the perimeter is changing every five years or maybe more, and so when the CEREMA was created, it was a national public agency. So we are still most of us are still working for the French Ministry of Ecology and Housing, but we are employed by this public agency named for Center of Expertise for Risk, human Planning, mobility, environment. Sorry, and yeah, maybe I.
Simon:I'll provide a link. Yes, okay.
Gaëlle :But so for we work on building. So the building sector in Cerema is about 200 agents, 200 persons, experts and specialists.
Simon:Wow.
Gaëlle :And we are 13 research teams, and so I am the how do you say? Deputy head of the research team focusing on building performance. So I am a researcher where, while some colleagues are not researchers but are more working for the government or for local authorities as well, who are the person in charge of implementing all the national regulations on energy transition, yes, environment and on the building sector. So in total, the CEREMA is nearly 2,000 persons with several sites in France. Every region has a CEREMA site, and I am located in the center eastern region, so near Lyon, for the people who know, our football team and the rest of the research team is located in Nantes, on the west coast. So here we are, like 15 researchers in my team near Lyon.
Gaëlle :The permanent researchers are people that are quite known in the IVC community, so they are Norwen Hurel, Basa Moujaled, adeline Melois, and then we have postdoctoral researchers, phd students, master's degree students and so on. So, yes, I think we are in charge in the research team. We are in charge of research program, I would say half of the programs. We are trying to work on barriers in the implementation of new regulations and to propose protocols or analyses or feedbacks in order to improve the next regulations or standards, and half of the other research activities are more based on more, I would say, academic study research studies, and we work as well for industrial partners and it's um, and it's had quite a good amount of output focused on things like ventilation and air quality, hasn't it over the last few years?
Simon:so it's that's definitely been. I mean being I know there's many areas that it looks at, but there's been some really good outputs from a ventilation and air quality perspective thank you.
Gaëlle :It's always nice to hear that. Uh, yes, I would say that at the national level, and even the international level, we we try to. So at the national level, we are really, we have been really involved, uh, so, with valerie le prince as well, who is not in the research group, but she is in charge of all the national activities and ventilation and indoor quality. We have quite been involved a lot in all the regulations since 2005. So we are in charge of national groups trying to make progress on these regulations and in these national groups we have, yes, all the communities concerned by the regulations on ventilation, air tightness and indoor air quality.
Gaëlle :So it includes, yes, private partners, building managers, representative of national community on buildings, and I think this is really productive because research is really in the process. It's not something beside, it's really integrated in the process to answers to field questions. So we have been involved in the, yes, the regulations where we have problems, we try to produce tools and we are as well involved in the trainings programs for private operators. So, yes, and at the international level, so Valérie is more involved in European standards. We are involved in the IVC because we really think that we have a lot to gain from sharing all the feedbacks at the international level, all the feedbacks at the international level, feedbacks from Europe, from France and from other parts of the world. So, yes, we are really interested to be really involved in this community.
Simon:Yeah, and that's how we met, I think, many, many years ago is at the AIVC conferences discussing what was happening internationally, which I think is a great conduit, I think, the AIVC for those discussions. So is Soema fully publicly funded then, or is it kind of a semi-private? You say you have private partners as well, you do some.
Gaëlle :Yes, our salaries are funded by the french government, but we have to, to collect, to collect financial support for all the rest. So for all the, the buildings, the travels, the yes all the other things than the salaries.
Gaëlle :so so we have financial targets to reach in order to reach the balance of Cerema. So, yes, we work with, we answer, we spend a lot of time for answering national and European calls, and I think it's like that in research in general. So it's not only here, but yes, we have to publish. We have targets for a number of papers to publish a number of papers with international partners and we have targets on an amount of projects have to be conducted with industrial partners as well interesting.
Simon:So how similar or how much crossover do you have with organizations like the cstb?
Gaëlle :then do you occupy similar, similar arena in a lot of circumstances yeah, so we cstb is really the national uh center for buildings, so they have don't know how many people, but they are really focusing on buildings where in serema, on 2000 people we are, are only 10% of people working on buildings. Historically we are not the same place because we were, yes, a government agency, whereas they are not. They are private. The, I would say this is a public agency, cstb, but they have to get funding for the salaries, contrary to us, and I am in the same in Cerema, we are in the same ministry that the people are in charge of developing and implementing the regulations in the ministry. So, yes, the links are closer for us and the financial supports between financial fluxes between CEREMA and the French government is not the same that between CSTB and the French government.
Gaëlle :I could say as well that CSTB does research but does as well other activities in the building sectors, like this agreement that we talk about for ventilation. We have many other agreements for all the building materials being used in France and CSTB is really the agency in charge of all these agreements. So, yes, we are like complementary, I would say. And on the topic of indoor air quality, ventilation and air tightness, we are not working exactly on the same actions. Sometimes we are together, but, for instance, cstb was really in charge of the National Observatory for Indoor Air Quality. Now it has been changed to the National Observatory for Indoor Environmental Quality. So we are in the scientific committee but we are not in charge of this observatory.
Simon:Very interesting in charge of this observatory.
Gaëlle :Yeah, interesting yeah. So yes, I would say that we are like complementary with CSTB and we are really specialised on ventilation and air tightness in CSTB, in CEREMA, in CEREMA.
Simon:Yeah, yeah, yeah. And what are the kind of things you're working on now then in that field, because the the last output I saw from you is, uh, beniette, I think was doing some work on categorizing different types of demand-based systems and energy efficiency and work around that. Are you doing anything new when it comes to ventilation and air quality at the moment? That's interesting.
Gaëlle :At the moment. So we are finishing this big work that we have started with the Annex 86 to work on some geometries of dwellings in Europe and collecting. We have collected, I would say, maybe seven or 10 types of smart ventilation strategies being used by partners in Europe. Sometimes they are really used in real buildings, sometimes they are just the results of scientific studies but they haven't been implemented in a real building at this stage. But we are also collecting these smart ventilation strategies and implementing those strategies in the two geometries and we are testing what are the performances. We are comparing the performances, changing the climates between all the participants of the Annex. So we have some Brazilian colleagues, we have New Zealanders colleagues.
Gaëlle :This is really not the same climate than here and even in Europe we have a very different range of climates. So we are testing the performances of all these systems. So this is one big piece of work. We are still working on the long-term durability of performances. This was a big project with two industrial partners in France with the humidity-based ventilation, and now we are trying to work on solutions, because in this project we work on the long-term durability of the performances. So the intrinsic, I would say really the performance of the ventilation itself, but as well how the ventilation system are maintained during the duration of the whole life of buildings and so on the maintenance aspect. There are a lot to do. So in social housing stock. Many partners are interested to continue the work and to find a solution to the problem of lack of lack of maintenance yeah, I.
Simon:I think there would be many countries the uk and ireland as well very interested in understanding more about long-term durability of various different systems. Um, because it's the great, it's the great next puzzle, isn't it? Like you say, we've spent a lot of time investing in understanding the installed performance of systems. We really need to understand better the long-term durability, replaceability, recyclability, particularly as other environmental considerations, like embodied carbon, start to come into play. We really want to understand the whole life cycle of these systems, and I think that's what's been fascinating about this durability monitoring that you've been doing is it's the first study I've seen that's gone right. Okay, let's look at ventilation systems that are a decade old and let's actually start looking at how they're performing. In this case, it was the humidity systems, though, wasn't it? In this case, it was the humidity systems, though, wasn't it, in particular?
Gaëlle :Yes, yes, it was.
Simon:Yeah, and that was because you were quite fortunate. There was a series of studies done a decade or so. Was it a decade? Probably more than a decade ago, wasn't?
Gaëlle :it.
Simon:Yes, yes, 15 years, yeah, 15 years ago it was a very famous study in France called the Performance Study, which you were lucky that many buildings were hardwired up and set up for the long-term monitoring of these systems, these innovative systems, and that's enabled you to go back many years later and revisit some of that work, hasn't it?
Gaëlle :you to go back many years later and revisit some of that work, isn't it? Yes, and we were lucky as well to have been able to have the performances at the commissioning stage.
Gaëlle :So, yes, we had this big project at the end of the yes, it was in 2007. So we were involved in the construction phase of the two buildings, one in Lyon, one in Paris. And so, yes, 15 years ago after sorry we went back to these two buildings and we were studying what are the performances 15 years ago and, yes, we learned a lot about the systems. We were quite impressed by the performance of the systems. 15 years after, we were impressed by the level of the level, the low level of maintenance. So most of the most of the exhaust devices there were really dark, even if you come two days after the maintenance.
Gaëlle :So the maintenance was just on the paper, yeah. So, and the the building managers were quite impressed as well, because they didn't. They they thought the maintenance was done and they never went on the field to to check that. So it was not always the case, but sometimes it was the case. But even with dark components dark components, dirty components we were impressed how the systems were still able to react. I don't want to say that maintenance is not compulsory yeah, but it's, but it's a reality.
Simon:You know that most systems are run to failure in the built environment. We tend to replace components in ventilation when they start making a noise or we become uncomfortable. They stop working. So we literally stress test every ventilation system to the point of failure.
Gaëlle :Um so it is interesting to go back 15 years later and see the the shocking level of non-maintenance really interesting yeah yeah, and they were pretty interesting photographs in that report yeah, yes, yes, we have many photographs and drafts as well of all the points were measured and how the deviation between the beginning the commissioning stage and 15 years ago was quite low in most of the cases. So, yes, we were really impressed, honestly, by the level of performance, even with dirty components. But once the components were cleaned, it was really really good performances in most of the case. So that was a very interesting point.
Gaëlle :We were impressed by the lack of data in the literature. When we tried to compare the results with other results, we really found nothing, nearly nothing in the literature, which is quite impressive as well. And because we were really in contact with the occupants as well, we were really impressed by the low level of awareness of occupants. I mean the low level of understanding about how works the ventilation system and what is the air in the building and so on where the air is entering, where the air is entering, where the air is going out. It's really something that people don't know or don't care, and I think it will be a next step in our research is to work with social psychologists and social science in order to work on that aspect as well, I think it's same case everywhere.
Gaëlle :People don't care about indoor air. And finally, I think that scientists have to work with people as well in order, because it's one piece of the puzzle. I would say If nobody cares about indoor air quality, we will never reach the target.
Simon:No, that's very true, and I was interviewing Sarah West there from the Stockholm Environment Institute last week. She's a citizen scientist and really interesting to get her perspective on that this. They have this saying no research about us without us, and I think citizen science has some real insight in how to engage with stakeholders because that's fundamental to how they approach their science. So I think there's loads we can learn in how we understand, how occupants and tenants and people understand ventilation. So, to summarize what you've been saying, basically, it's probably not a surprise to anybody on this podcast that demand based systems can be robust and I think by nature they're quite robust because they can go so above the ventilation flow rates and below that they've got a little bit more adaptability perhaps than fixed systems. That basically nobody maintains ventilation systems and nobody understood what they had in the first place. Um, so I think it's a good picture of where we are.
Simon:Probably with ventilation at the moment is uh, we've got there's some low hanging fruit. Let's say that we can. There's lots of opportunity to improve. What have been the big lessons for you out of that performance project? So have you been able? Is there? Has that kind of spurred some ideas about what next, like you say, engaging with homeowners better or engaging with industry about maintenance of systems in a different way or like? Apart from understanding that demand-based systems can be robust and have some long-term strengths, is there are some other takeaways from that study?
Gaëlle :uh, there are several aspects. The first one is that, um, now we are really I would say we are really, I would say we are really sure that in the French context, this humidity-based ventilation system are the good, probably the best answer to the challenge, because I mean spending a lot of money in developing new innovative systems with a high level of technologies in the world, where we have, yes, a limit in the availability of materials and availability of electricity and so on that I think now it's time more to focus on the solutions which already exist and to study the range of performance. I mean, for instance, the humidity-based ventilation is a good answer in France, but maybe in a country where there is a I don't know, I don't know, but I could say in a country where there is a high level of humidity outdoor outside. I don't know, it's just open question. At this time Maybe it's not the good solution or I don't know. So at this stage we are not able to answer to all these questions, but in the French context, we know that we can say energy, that the level of indoor air quality is really acceptable, that the solutions are robust 15 years after, even if there is no maintenance. I would say what else? We are just quite pretty sure about these systems now and we are at this stage where we would like such solutions, which are economically very acceptable because they are really cheap as well compared to other systems.
Gaëlle :We are at this stage that in some countries where they don't use a ventilation system at this stage, maybe they could have a look to these systems, and we would like. It's not. I really have no financial interest in French manufacturers and so on. It's not really. It's really not the idea. It's just identify in all the countries where such solutions exist, where they are robust, where they could work even after 15 years, and trying to leave all the markets open to these solutions because it's just saving time and saving energy. So we are at this stage. We need to work on maintenance, as I already said, and we need to work on other aspects, like thermal comfort during heat waves, because this is really a challenge here in France, but not only in France, and at this stage, all the performance assessment schemes are focusing on the heating seasons. So, yes, there is a challenge for the systems to reach good thermal comfort during summer as well.
Simon:Interesting.
Gaëlle :And this is not taken into account at this stage in France. So working on future climate scenarios and testing, including new performance indicators based on thermal comfort and quantifying the performances during this period, is a challenge in France.
Simon:So what do you think is next then for smart ventilation and demand-based systems? Is it that broader expansion, as you described, into indoor environmental quality, that there's just much more in the pot that we now need to consider when it comes to optimizing the built environment? Is it just finding ways to introduce that complexity, do you think? Or is it about getting the basics right, as you kind of indicated you were saying just now about actually, we do some stuff pretty well, let's just concentrate on that.
Gaëlle :I think that there are two stages. There is the immediate stage and then the middle term or long-term stage, and we have to focus on the two stages at the same time. So the first stage is just that now we are ready, I think, to have regulations everywhere for making it obligatory to have mechanical ventilation, I would say in all the climates who are compatible with that, I mean in some climates maybe natural ventilation is more a solution than mechanical ventilation.
Gaëlle :But I don't have the exact answer and the exact globe world image on where it's the solution or not. But I know many countries around the world where they should have mechanical ventilation and they don't have it, should have mechanical ventilation and they don't have it. We know that once we have mechanical ventilation compulsory in the regulation, it's not the only solution. As we talk about that, we need inspections and we should do like they do in Ireland making the regulation at the same time requiring inspections. Otherwise it won't be done in the proper way. I would say the ventilation system won't function in the proper way. And we know that we have mechanical ventilation. So it could be balanced ventilation. It could be smart ventilation, depending on the climate. It could be balanced ventilation, it could be smart ventilation, depending on the climate. We have to identify where those solutions are the best ones and we have to open the regulations to performance-based regulation. Like that, we don't make a choice between the type of mechanical ventilation. We just say you have to reach the target. Once you reach the EAQ thermal comfort target, the system can be installed in buildings. So, yes, these are the immediate answers, and we know that many ventilation systems exist and they are performing quite well. Smart ventilation, but not only smart ventilation. I would say yeah.
Gaëlle :And then the next stage is at middle. At middle, in some years, we have to be ready with the climate change. And we have to be ready with the climate change and we have to be sure that the systems which are installed today are still functioning in 10 years, 15 years, maybe 20. We don't know exactly what is the duration of the ventilation system in buildings, but maybe it's 30 years because they are never changed. So, yes, we have to make sure that these systems are still working in some years and we have to make sure that they will be still the good answer in 10 years, and this is quite challenging. We have quite good climate scenarios, including temperature, but we don't have very precise scenarios concerning humidity in the outdoor air, so this is a challenge, and we don't have all the performance indicators, so this is quite challenging.
Simon:Yeah, and you think that's where the pinch points will be in the future is not just systems being fit for purpose from a maintenance perspective, but actually fundamentally fit for purpose by their design for changing in environmental conditions, whether that's temperatures or air pollution or moisture, you know it. It's it's trying to understand where we start to hit some glass ceilings with some of these technologies that we may be not anticipating at the moment. Yeah, yeah, no, that's really interesting.
Gaëlle :There are so many things to take into account when we are thinking to the future. There are the fires. So some countries are already experiencing many fires compared to before, and so this will affect the strategies. For instance, in Europe, or at least in France, compared to America, we don't use so much filtration strategies. In some countries, yes, like Poland, they are really used to have outdoor pollution, but we are not used to that and we are not used to have outdoor pollution, but we are not used to that and we are not used to have fires.
Gaëlle :So, yes, this is an example. We had the COVID crisis and we know that pandemics will be, we will have more pandemics in the future, and so this is another type of aspects that we have to take into account in the ventilation strategies. There are so many things, but already researchers are working on resilience in Kauleven, for instance, with Hildebrecht, or many people involved in the Venticool platform and the annex it's the 80, I think. So, yeah, researchers are working already on that, and I think in the real world as well, in buildings.
Simon:But again, some, some of us are already experiences, experiencing sorry issues that we we will learn from from them and we have to continue to work together around the world in order to avoid surprises that are not surprised for other people yeah, no, absolutely well, and we'll get to discuss those and many more subjects at the AIVC conference, which happens in October, the 9th and 10th. So, for listeners, if you've had an interest in some of the stuff we've been talking about in this podcast and over the last year, many of the guests on the podcast and authors of the studies that we cite are going to be at the AIVC conference talking about some of this latest research and clearly have you got some things you're talking about this year, girl, at the the conference yourself um, yes, I'm laughing because just before the recording colleagues told me you have four presentations.
Gaëlle :I was thinking four. No, I don't think so. So I checked. I have two presentations, but two have been assigned to me. But they will be done by colleagues. So yes, we are working. I am introducing a topical session on performance-based approaches and regulations, which is organized by our colleagues from Spain, pilar and Sonia, and I am presenting the status of ventilation in France in a topical. Presenting the status of ventilation in France in a topical session with status of the ventilation aspects in several countries, because we had a series of VIP in the AIVC community and so some colleagues are presenting their VIP.
Simon:And I'm chairing that session, I think, along with, uh, valerie, yep, so we'll be. We'll be, um, I'll be talking about ireland, you'll be talking about france, and we have some other countries as well presenting where they are, um, so I'll share the links in the show notes for the conference if people are interested. It's well worth trying to attend if you can, and it's in Dublin as well this year, which is a great city to visit, if you can. Gail, thanks so much for your time today. It's been brilliant talking to you, as always. I look forward to seeing you in a few weeks time and we really appreciate the time you've taken out to talk to us.
Simon:Thanks a million. Thank you, simonon, for inviting me. Thanks for listening. Before you go, can I ask a favor? If you enjoyed this podcast and know someone who might be interested, do spread the word and let's keep building this community. This podcast is brought to you in partnership with 21 degrees lrees, lindab, aeco, ultra Protect and Imbiote all great companies who share the vision of the podcast and are not here by accident. Your support of them helps them support this podcast, so do check them out in the links and at airqualitymattersnet. See you next week.
