124 - Advancements in Fire Safety of Facades with Eleni Asimakopoulou

Hello everybody, welcome to the fire science show. Today we're discussing fire safety of facades and the facade subject. Even though it's one of the most popular in the fire safety science, it has not been that much in the podcast, I've realized. And we had a good opportunity to catch up on the subject for the IFSS conference, which I'm actually right now in. We have planned a facade workshop. For this facade workshop we had two hosts Dr Lenya Simakapulu and Martin McLean. I knew that Lenya can't come to Japan, so I chose to interview her instead and see her broad perspective on the realm of the fire safety facades. And this exactly is the today's episode of the fire science show. So we are discussing the research, testing and modeling landscape in the realm of facade fires pre-grantful, post-grantful, how it evolved, how it changed, where some stuff originated from and where are we going with it. So, hopefully, a nice overview of what's happening around on the facades and perhaps a lot of ideas for new details. Podcast episodes about the most interesting technologies brought up in there. So let's not prolong this, let's pin the intro and jump into the episode. Welcome to the fire science show. My name is Vojty Wigzynski and I will be your host. This podcast is brought to you in collaboration with OFR consultants, a multi-award winning independent consultancy dedicated to addressing fire safety challenges. Ofr is the UK's leading fire risk consultancy. Its globally established team has developed reputation for preeminent fire engineering expertise, with colleagues working across the world to help protect people, property and planet. Their project portfolio includes a lot of buildings at King's Cross, including the new home of Metta, which is open in March 2022. Ofr is also part of the Thomas Hethaway lead design team creating the new landmark campus for Google, described by the Guardian as the land scraper as long as the short is tall. This new HQ is highly anticipated hub comprising workspace and retail and community spaces. If you are interested in working on projects just like that, ofr is continuously growing in steam and is keen to hear from industry professionals who'd like to collaborate. Get in touch at ofrconsultantscom. And now back to the overview of the Fassad 5 science. Hello everybody, I'm here today with Dr Lenny Asimov-Kopoulou from University of Central Lancashire. Hey, lenny, good to get to have you in the podcast.

Hello boys, thank you for having me.

And we're gonna talk Fassad. A few years ago, after the Grenfell tragedy, it was in the very focal point of many, many researchers and research units in the world. You were one of those who were actually studying this before Grenfell. It's not just the accident that led us on this subject, but there were researchers already working on it and it just accelerated. I'm really looking forward to learning from this talk on how the landscape has changed since. So, first of all, maybe you can give me a brief summary of what you were researching since time of Grenfell and now and how your research has evolved, and then we will go into details.

Okay, well, certainly this has been a topic that has been going on since many, many years, especially since high-rise buildings has been widely used and we see a tendency of using new materials into facades in order to improve energy efficiency. So this has been happening for quite a long time, and even way, way many, many years ago. Back in Japan, there has been substantial research of trying to understand how buildings were responded, and Fassad was part of it, so definitely it's not something new. If I go back in history a bit, even back in 1994-5, bavlowskas was discussing issues and then had it just back in 2015, publishing a book about it. So to discuss a bit my relationship with Fassad Fais, I used to be part of the laboratory of heterogeneous mixtures and combustion systems in Greece. I was very fortunate to have a very active professor, maria Pfoodi, that was doing a lot of European projects at the time. So what was the situation back then, almost 10 to 15 years ago? That used to be funding from the European Union to investigate new materials okay, energy materials but little attention was given to the safety aspects of it.

What was the driver of this research? Energy efficiency sustainability.

Energy efficiency and sustainability and producing modular components to be used in Fassad thick ones, but also energy efficient ones. At the time people were discussing safety issues but it was not high in the agenda. But, being from a combustion background, fire has always been something that we try to implement in our research. So we try to make sure that we have fire safe buildings along with energy efficient buildings. As part of that, we had many projects. One of those was Elyza, a European project, and as part of that we tried to investigate how ventilated facade systems would respond to fire and whether they would actually deteriorate the development of external venting flames. As a note here, the facade, the ventilated facade system, was not combustible. It was a series of experiments performed under three megawatt fires full fires, liquid fires were used, and we did use instrumentation record temperatures at the interior of the fire compartment which is another aspect of testing and issues currently investigated and also externally, along with the temperature profiles at the facades. We did found out that actually, for the specific configuration we tested, having non-combustive ventilated facades wouldn't deteriorate facades fires. But I think from your experience you can understand that the statement is crucial here the specific configuration we tested, under the specific conditions we tested and the result is to be applied only to the specific system that we refer to. I don't know if you're confused with that.

Were you investigating the conditions within the cavity itself or you were looking on the general whole system behavior?

Yes, yes, both actually. So we had the perforated metal barriers alongside the facade, positioning at 1.5 meter distances, and we had temperature thermocouples measuring temperatures at the interior, so inside the gap, but also alongside the various layers of our systems. But we also had approximately 40 thermocouples at the exterior of the fire compartment trying to measure the properties of the facade fire. And additionally, we had cameras positioned at various places and we did use image processing analysis to calculate the intermittency and various claim characteristics. And also we did have heat flux meters alongside the height of the facade to actually try and estimate the heat impact at the facade side.

So the point was comparing a non-ventilated system to a ventilated system, taking out the combustible material part and just focusing on the technical solution. Did it already highlight some specific issues with ventilated facades and later were challenged in the combustible systems?

Yes, I mean this was a system that was developed at the time, so we did make sure that it would have been safely produced. But, that being said, it was not a standard test. So it was a test format along with a fire brigade in Greece. So exterior environment, which is also debate now Should we have tests done at the exterior or inside big labs? So it was a tailor-made experiment for the specific needs of that research project.

I actually found a paper. I have it in front of my eyes. I put the links to the resources in the show notes of the episode. So if anyone is interested in those particular outcomes, you're very welcome to check the paper. But I've invited you not to talk about a single paper. I want to have a holistic view on the issue. So you said that the research was ongoing already and there was an investigation in materials from the energy efficiency point of view, how exactly that connects to the facade systems and how much you can actually save energy in building from simply the facade.

Yes, it's of great importance. I mean, this is the end for the building, actually enabling heat to be transferred from the interior to the exterior and vice versa. So it's made the effort to actually try on efficient systems to be used in order to have improved energy performance. So, for example, there are many different systems, so you might have a combustible type of system, but if you have the right encapsulation or if you have the right chemistry or you can have additives or add it only. Even some companies have produced materials such as phase change materials that can't be positioned inside the plasterboards or things that wouldn't normally burn, but there are hidden dangers to it. So, ok, we do talk a lot about polyurethane forms and polyestrials and things that were associated with the Grenfell fire, but we shouldn't forget that there is a plethora of other materials out there. Now I'm in favor of investigating new materials, because this is how science will progress. So I have my doubts regarding planning specific materials that can potentially be eco-friendly and of great benefits if they are appropriately used. And, for example, it's been many years now that Sweden and, for example, rise, has done plenty of research into wooden facades. The same applies now with the University of Queensland that they have performed plenty of research into wooden facades and how those can be made safely. And, on the other hand side, we shouldn't forget the interior of the fire compartments. So this is a totally different conversation, because we should remember that external venting flames do depend on the properties of the fuel burning inside the compartment. But also there are many issues that have not been studied in details as of yet, such as, for example, glazing and how new glazing materials would react to fire tissues. So, for example, we have new glazing with new coatings that we don't exactly know how they would interact as part of systems. That takes me to a different discussion. Sorry, I tend to talk a lot.

You're a lecturer. And the second thing, this is the reason why I invite you to the podcast. First of all, we're talking about ventilated facades. Let's define this for those who may not be familiar with this exact technical solution. So what is ventilated facade and why is it ventilated?

Okay. So you need ventilated facade systems to be used in many different, for many different reasons. For example, they're very good for energy efficiency because actually, air is a very good insulation material. So, to first reply to what it is, it's a facade system that contains air as part of their layers. It can be any type of system, so you can have cladding, eddix, and different types of systems used with different materials, but if you have one of the layers being gapped with air, then you can call that a ventilated facade. Now, the thing is that this is a very general description of a facade, so the depth can vary from a few centimeters to many, many centimeters in depth. So this is why we actually should come back to the fundamental type of research in order to understand how fire would evolve inside a cavity. So this is something that has been investigated from many different people around the world, so I will get back to the testing. For example, there are standardized tests in the US and Australia that give the possibility to change the depth between two non-combustible surfaces and then you can put a burner at the bottom and see how the flames will evolve.

And, to my best understanding, the discovery is a fantastic place if you're a fire, because you have re-radiating surfaces, high velocities, fairly good access to air, so everything you would like as a fire to thrive. You also mentioned combustible, non-combustible facades. If I understand correctly, we would be talking about the external part that I think is called cladding and something that you put on your wall insulation or whatever that layer may be called and you probably can end up with different combinations of non-combustible cladding, non-combustible insulation, non-combustible insulation, combustible cladding, like any combination of anything that is combustible, would already mean that the whole system is combustible. How would you define it?

Well, this is a very tricky question. If you have a combustible component, then you have the potential for combustion to kill.

And how about this? It's a different story.

Yes, now, and that's a story of testing.

Let's go there.

I don't know, but that's an interesting thing because, for example, you can have two metal plates and then you can have a polythene that can burn very fast. But if you're sure that your system wouldn't fail, then why not use it? But this is a question that we should all try and answer. Is it a safe component, Is it a safe system? So this is another discussion, because we have a very specific test to account whether a material is flammable or not In terms of small or medium scale testing. But when we go to large scale testing, there are various issues to be discussed. So another issue when it comes to ventilated facades is the cavities. Barriers can be used.

Like elements that split it. You mentioned Porus plates seconds ago. You use metal plates with holes, so that's one solution. What are the solutions that there are?

There are many other things you can even use in my painting as part of it, or use. I mean a very plain and simple one would be to use rock hole barriers.

Okay, like mineral wolves just closing the cavity for a part of it, okay.

But then how to test its efficiency. It's a whole different discussion because, for example, in the BS8414, there is no specific requirement where you should put your fire stops in relation to the height of the fuel. We can imagine that actually that can have a mental effect on whether you will have a pass or a fail, because let's imagine that you have a barrier close to the fire load that can fail easier than if you have a 2.5 meters higher.

So let's move to the testing regime. So how does the testing landscape look like as a part of a testing laboratory and I've done a lot of those tests myself I clearly see there's a lot of different approaches, so maybe you can summarize to the listeners like what's happening around. How are we testing facades today, perhaps after we can move into the mythical European method that is coming our way sooner or later?

Yes, sooner I guess, but hopefully so. Since the European one is a hybrid one, it's good that you propose to start with an overview. So traditionally, there have been many large-scale facade tests, but also medium-scale facade tests around the world.

Where you would put the distinction.

On the geometry and the fire load. So these are two different things. So we need to have an understanding. Do we refer to geometries or to how severe fire events were trying to investigate? In some countries there are both tests. In others there is the large scale one. Additionally, one of the oldest one is the German one, the DIN4102, which uses a lateral wall and it's 5 meters long, and this is also a difference. Some tests have a lateral wall, some tests don't.

Corner versus a plain wall?

Yes, yes, and actually this is a big difference because for the people that are studying fire or work with fire, we know that air entrainment is a very important parameter. So having lateral wall would influence how the fire would develop, but also that represents realistic geometry that could exist in a real building. So there are positives and negatives into having that. Personally, I think it's a good representation of real geometry and I'm in favor of having lateral walls. Now, the other thing that makes difference in the various tests large scale infosub tests around the world is the existence of an opening. So you can have an opening on a higher level than your fire source or not. Now we need to step back a bit and discuss what is the fire load. So there are two mentalities of testing. You can have a compartment attached with a facade that can include a fuel source, such as wood creep, or a liquid fuel or a gas fuel, or you can have a different type of source that is positioned at the exterior of the facade. So you can have, for example, as the American test, a gas burner attached to the lower surface of your facade, which is a big difference when it comes to how the fire will be developed. Now another thing is the duration. So you can have a test that lasts at around 30 minutes, or you can go to a smaller test. So, for example, the Swedish test has a minimum of 12 minutes, where others don't have a minimum. And also, if I go back to the windows, as we discussed, you might have a compartment attached to the facade, and in that facade you may or may not have an opening. So, for example, in the England test, in Germany, you don't have an opening. In the UK test, the BS8404, you don't have an opening. In the American test, you don't have an opening. In the Swedish test though, the SP105, you do have an opening.

And actually you do have two openings on top of your fire source In Hungary you have an opening, and the American is really intriguing because you actually have the compartment there. It's just no opening to it.

The thing is that the mankind of developing those tests is different, so you have developing different tests.

And also they were created in different times. You did not have ventilated facades and post-grantful environment in the world. These methods have been here for ages. The Polish method I'm not sure if you're familiar with it the small 2.5-meter wall, wind and everything that was developed in my institute in the 80s Because we needed something for quick assessment If the facade systems are generally OK or not. Ok, quite simple method was created which actually passed the test of time because it allowed us to have quite a stable system in this regard in the country. But it was end to the environment. But today we're in a completely different place. Today, after the grantful discussion, no one today would be questioning it's not a serious issue. No one would be telling you why you're researching facades Like they don't burn or they burn very rarely. What's the point of doing that? No, we're way, way, way past this discussion and yet today we are actually having a new method being implemented. So, let's put the European method on this landscape.

I mean, this zone started some years ago, actually post-grantful again, so it was back 2019 or 18 that was extended from the European Union to actually develop new European fart tests specifically for facades. And this is a collaborative effort with many, many, many partners with great experience, such as Rise and Bam and even a golf was involved in that and some universities, and the concept was to first try and understand what was the different methodologies around Europe really, but also it was pro Brexit, so UK was included in that research and then through I think this is still an ongoing project, if I'm not terribly wrong they have narrowed down the various parameters that should be implemented. There's now a recommendation for two different tests to be implemented according to the intensity of the fact that you want to investigate, and actually this is a hybrid of the German and the British standard, so it's a hybrid approach. So try to use the positive aspects of those testings and actually implemented some differences. So, for example, it's very similar to the British test, but also the new European test for intense fires would have an opening. An interesting aspect of it is that the opening watch will not be at the centerline of the opening of the compartment part, but it will be off center, which is an interesting aspect, because I mean, as you can imagine, you need not only see if the blazing above would fail, because this has been done in the past. For example, one amazing research was from Kloppovic back in the 90s on façade fires. Amazing research she did, and a female engineer, by the way. So they put it off for the centerline to investigate whether you would have some of the systems surrounding the opening fail. Also, quite an increasing duration, so 60 minutes, and it's a three megawatt fire, if I'm not wrong, with an option to have both gas or wood.

Okay, that's interesting. Yeah, I don't completely understand the existence on Crips. I mean, I recognize that Crips can burn very in a repetitive manner, but also is uncertainty related to the fuel sources or how like you can have a moist. If you don't have perfect control over the moisture of the Crips, it can be challenging, but it's great that there's a gas burner in it.

Yes, I mean, to my mind, also for standardized testing. Except you can make sure that you have a conditioning role to put the Crips and you can assure that you have the same Crips, wood species, used every time, consistently and with the same humidity, treated the same way and put. There are so many aspects of it. But yes, I would echo your comment that actually humidity is a huge parameter here and a recent publication highlighted that actually, having taken the lowest limits when it comes to humidity, because there are specific thresholds that are allowed, if you take the lower limits you can have up to half the total heat release rate produced by the same Crips at the same environment. So that's not a parameter that we should neglect. Everything.

I shared this observation like, really like this. Variability introduced by moisture can be huge, following on the window detail. Let's try and understand that from the construction of the facade perspective. Because if everything you only cared about was the glazing, you could probably go away with putting a plate thermocouple there and approximating the heat flux there and just assuming some critical value or even assuming some temperature at which the glazing would break. But however, introducing a physical opening in that test forces the participant of the test, the company that's testing their facade, to actually work on the technical details around that opening. And, to what I understood from the existing research, these tiny details can in some cases make or break the facade system. What's your experience with that?

Yes, yes, this is a huge point here. So, for example, I was part of the European project that investigated how sealant should be used around openings, what is the most efficient materials, but still there is no specific guidelines out there. So another issue that I would like to discuss is you did mention companies, and companies wanted to test. So another thing is what is being tested and what is being applied, which is another huge thing, so testing construction details is of paramount importance and actually they should be documented in the report and actually this is part of the new European testing that details on the constructions will be implemented in the report. Mandatory.

So placing them in the test makes a good pathway to put them in the certification documents. But, come on, that also limits the scope and we're talking about a massive test. I'm in the business. I know how much it costs to run a414 and this is a similar scale. So I wonder to what extent we will have flexibility with that or to what extent people will have to go through multiple, multi rounds of tests to test different tiny details of the system. I don't want to argue that it's not important, because I absolutely understand how important the details are, but I also know the market and I know the negotiations between the laboratory and the companies and I know that if there's one thing they're going to battle for is to reduce the number of tests and make it as universal document in the end as possible.

True story. So we have a huge battle here. So there is a battle of the cost versus safety. So, this is like if you imagine a Pareto front. This is a case you want to do things as low in budget as possible but, at the same time, produce very safe products and systems, which is a contradictory thing, and this has always been the case. But, as research hasn't, actually the key is of importance. If it wasn't, then we wouldn't have large-scale testing.

But both the scale of the size, geometry, or only the scale of the size of the fire, which you could probably reproduce in a smaller setting.

Well, I would argue both. But still, if you are able to upscale your results in using proper mathematical tools, then fine, do it, because we cannot expect that it's not practically feasible to test all systems to be installed in large-scale assets. So this is that way. It's important to try and understand the physics of such fires and try and see how those fires will evolve, regardless of the testing procedure. So this is why actually research towards using other tools, such as CFD or finite element, or even coupling CFD with finite element analysis, can give us a bit of a confidence, trying to understand the mechanisms and then potentially upscaling it so we can do research, for example, and we do large-scale fire testing for every different system out there.

Well, if I'm selling, I can do as many as you like, but I am very doubtful there would be a company or a group of companies that would be interested in paying. So you would say that future would be in a coupled testing regime, enhanced by some sort of modeling simulation tools that would allow us to expand on those results. Can you elaborate on that?

I think that performance-based design enables us to use other tools. I have huge confidence and I'm totally in favor of large-scale facade testing. Don't take me wrong at aspect here. I do believe that we should test, test and test, but on top of that we should develop other methodologies to support this knowledge, because we will test part of the facade, but was Grandfilm Tower just innate by two-meter facade?

With no opening, no.

With no opening and with no influence of wind and I don't know multiple file sources at the same time. So this large-scale facade fire testing is a representative scenario, worst case representative scenario. I'm confident of that. We need to be clever. We need to take advantage of new tools that exist out there machine learning and CFD. So there is a lot of research on developing CFD methodologies to be used in facade fires. There are many groups around the world that invest a lot in such tools. I've been very fortunate to observe many interesting PhDs recently on those topics. One of them will also take the SFB Award on the best thesis, which is amazing work done in USTC and University of Vienna. So we are developing new tools to try and see how we can cap on CFD in order to predict behaviors better. Now the other major work stream is how we can actually cap on CFD with finite elements, because we are well aware that some of the software's out there have restrictions when it comes to calculating the heat transfer at the solid boundaries. So coupling CFD with finite element, I think, is of great importance in order to have accurate results. On the other hand side, people that will work with CFD, as yourself and others, would know that if you want to do assimilation, that the class for like a medium scale type of testing that can take up to a week. Even if you have very good computers and with a very good PU, this is not feasible. If you want progress, that I see many roads ahead. So, for example, what about using CPU instead of CPU? One way. Another way is to actually try and use machine learning, so the FISIM intelligence and you had many great scientists talking to your show about AI we can use both hybrid approach, using both experimental data and CFD simulations in order to feed our neural networks and produce some results.

So you said you're a huge believer in CFD modeling. In this I'm also, to extend, a huge believer, though I have one issue with it and that's the two-sided coupling. It's not just that fluid simulation couples to construction and provides it with thermal information, but those things really get damaged. The grade in a time scales that are relevant to fire, like if I do a couple simulation for a wall and it collapses into hours and I just was interested in fire resistance of that wall, that's it. I don't care. But if I have a 5 centimeter cavity and I know this panel will fall off after 5 minutes or you know it will bend and suddenly the cavity will be 10 centimeters or 20, this kind of changes the flow filter significantly. I would never say it's insignificant. I mean I know it's omitted today because we don't have good capability to incorporate this other feedback, like how the change in the structure changes the flow feel. But I think at some point it will have to become important in those considerations.

Yes, I would agree with you. I mean, if you have a serfans heated, then you would expect, in the scales that you did mention, that you would have re-emitted back to the compartment of the fire origin, or vice versa. Or suddenly you can have a compartmentation lost, and this is a capability that is not currently embedded in most of the CFD available, and actually this is the real. So I think you highlight the importance of having real-time fire structure interaction, so not just feeding the finite element more than as a boundary condition, but instead having a communication. Now, I am aware of some people working on that, but I don't think this is a mature product that is ready to be used extensively for our community. By the way, even people working with CFD and finite element interaction, the process is not very straightforward and it takes a lot of effort to produce results. You need to have a small algorithm connecting the output. It's something that it's not to be used extensively in the next months, I would say.

Whoever is serious about it the moment they discover how difficult it is to even simulate convective heat transfer. If you really want to know it's not just a sums some value and have it approximate, but really similar. There are challenges on the way, which doesn't mean we shouldn't try. It's important to try and I also have a feeling that, with the diversity of the solutions that will come to the market and also having a tool that actually an engineer can work, because if you step beyond the compliance, beyond the testing, there's also an engineer that will be designing a building. And also said at the beginning of the interview, perhaps a combustible facade. I mean it can work in some settings. I can envision a building which has a wall that's completely closed, no windows, no openings. It's a wall of some less-past-populated building. There are risks overall could not be huge. Perhaps if it solves your issues with energy efficiency, perhaps that's a setting in which you could apply it safely. But the safety comes from the context, not from the solution itself. It's always solution the building and the possible fire.

Yes. So that's why we do have a need for tools to be widely applied, such as, for example, the effect tool, as developed by an FPA, which can help us evaluate external facade fire components and how those should be used, and, on the other hand side, I would say that we should be mindful of new technologies. So another research thread that exists at the moment is how we can understand how fires would evolve into smart facade systems, such as facade system with implemented football-type panels or systems. So there's currently no guidelines and actually I would find that there is a gap on guidelines provided to fire engineers on how properly use safety, for example. So, when it comes to training, yes, there are people out there that provide training to people, which is fine, but still there is no uniform approach. Neither that are specific guidelines for the people to follow. So can we trust always see if the results?

I'm not sure Because we're closing to the finish. So what would you observing, like the past, pre-grantful, the research happening after grantful, the emergence of the new testing method, people realizing that SBIs perhaps not the best tool to assess safety of facades and note that there has been a lot of progress? How do you feel the environment evolving? Where are we heading with this? What would be your predictions for the new future?

Unfortunately, we are guided by catastrophes in this field and I can certainly see that grantful hard-pressed towards having robust methods in designing fire-safe facades. Now I think that there will be a research effort towards understanding the fundamentals, and it's funny, but I don't think we're still there. So I'm not sure what we do understand fully. What are the physics of flame inside, on the flame development inside the cavity? Neither do we fully understand the fact or start influence external venting flames. So if we start from the fundamental type of research, there is still ways to go. So people now are investigating combustible facade materials in various scales using tools that did not exist in the past. So people are trying to connect between medium-scale testing and large-scale testing. So there are libraries developed with available tool information on material properties that we can now use in our analysis. So this has been a very interesting thing. When it comes to testing, we see various research organizations, even private companies, funding comparative facade testing in various conditions the interior, the exterior, addressing various issues in relation to the use of materials and fire breaks and the use of wind elevation. There is a lot of research now on what is the impact of air entrainment. So should the test start from the bottom touching the ground, or should we have a gap from the burner to see the air entrainment from?

the side. Yeah, this is very, very interesting Something I also had witnessed firsthand. There is this funny let's call it funny test, small iso test. I don't recall the number of the standard from my head, but it's literally a small 100 kilowatt burner. It's a linear burner, but the trick is you put the facade directly above it, so the bottom edge of your facade is directly above the burner. That thing it's through the facade. Seriously, if you told me there's a 100 kilowatt burner, that's easy, but the fact that it simply goes into the yes you have direct contact with the flame. Direct contact exactly. Yeah, that's really really impressive.

Yeah, but still we need that to figure out lots of things. So, for example, what about non-rectile energy geometries? So, how can. A facade would influence the development of the fire. And then combustible materials. I mean, simply banning them is not a solution. We should find clever ways to improve them instead. So a lot of people are studying how we can do that. Also, how we can test a futboletikes embedded in facades in a horizontal direction, how we can design facades that are safe if we have energy storage systems installed at the vicinity of the facades. And, to conclude, how we can combine technologies from other disciplines for designing a safe system. So this has always been the case with fire, where a combination of chemistry, of heat transfer, of material science, of I mean how many disciplines you need to understand in order to part understanding fire.

Yes, especially in such an interesting setting of a ventilated facade. Lenny, thank you very much for this very interesting update of what's happening in the realm of facades. Definitely a lot of interesting stuff happening around great research, great progress, great developments in the European test method. We'll see. It still has to stand the test of time, so we will see in 10, 20 years if it's really a great method. So far it looks interesting, at least Looking forward to see. And you opened. I cannot concentrate because, like PVs in facades, that should be a podcast episode.

actually there is so many we will test that at the moment, so hopefully we'll have some results soon.

Thank you so much, lenny.

Thank you very much.

And that's it. Thank you for listening. Hope you've enjoyed this update on what's happening in the realm of facades. I can just add that we have finished the workshop on facades in Tsukuba. It was very interesting. I had the chance to talk a bit about the green facades and how we were designing them the ones that we believe that are a little bit more safe, at least. Karan Guskak presented some insights into exposure conditions in relation to timber compartments for facades and Julian Mendez shown his research on the cavity flames and measuring those. A lot of interesting discussions that followed. It was like the workshop was mostly discussion not presentation. So, yeah, it was great to catch up with all the bright minds in the realm of facades and, as you can hear from Lenny Sok, there is so much going on, so much to do. These efforts will, for sure, continue. So that would be it for the facades subject. Thank you very much for listening If you're listening on time. Apologies that this episode was a little late. It's not that easy to produce the podcast from and a hotel room inside the International Conference. I guess this experience is something I have to take in future planning. But next week, thankfully, I'm home and nothing should stop me from giving you five signs on Wednesday, as you deserve it. So thank you very much and see you here next Wednesday. Bye.