Fire Science Show

200 - Façade flammability across scales and standards with Guillermo Rein and Matt Bonner

• Wojciech Węgrzyński

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Episode 200! And for this special episode,  I've travelled to London to interview Prof. Guillermo Rein and Dr Matt Bonner on a piece of research carried out at Imperial College London, with the experiments performed in our laboratory at the ITB.

In this episode, we discuss the concept of flammability of the building facades and how this flammability is assessed with different testing methods available in the world. You could argue that every country has their own method, and in some cases, they use those methods even with varying criteria of acceptance. Even though the methods are as different as they can be, they all claim they test for fire safety of the external façade and are used as the basis for local regulatory regimes. Knowing that so many methods exist, we approached this with a question: Will they agree on ranking different facades? Will they show us the same results, or will each show us something else? And this question is inspired by Prof. Howard Emmons, who in 1968 went into a similar endeavour with building materials. Back then, Emmons said:

“Such profound disagreement between serious attempts to measure combustibility points out better than any argument that we really don’t know what we are talking about when we say, ‘this is more combustible than that’; ‘this is a more safe building material than that’”.

In this podcast episode, we discuss a series of 25 experiments: testing five facades, two ETICS and three rainscreen facades with a varying degree of use of combustible materials. All the material combinations were built by us in the same way, and then assessed using five test standards: 

  • The Polish method PN-B-02867, 
  • The international screening method ISO 13785-1 (smaller corner configuration), 
  • The German method DIN 4102-20, 
  • The American method NFPA 285, also used globally
  • and the British BS 8414, also highly influential over the world and the basis for the new harmonised EU approach.

We go into the background and rationale of the experiments, an overview of the testing methods as well as into qualitative and quantitative findings of the study.

Once the paper is published, I will update the shownotes with a link here :)

For now, you may also want to revisit previous episodes of Fire Science Show discussing the fire safety of facades – 

This research was funded by The Berkeley Group. The experimental part was performed at the Building Research Institute ITB, with a group of tests with the Polish method performed as part of our statutory research NZP-130.

Thank you for being with the Fire Science Show for 200 episodes! Huge shoutout to the OFR for enabling this project and allowing me to share insights like this with all of you in an open-access repository!!!

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The Fire Science Show is produced by the Fire Science Media in collaboration with OFR Consultants. Thank you to the podcast sponsor for their continuous support towards our mission.

Wojciech Węgrzyński:

Hello everybody, welcome to the Fire Science Show episode 200. That sounds kind of surreal, but I'm super rejoiced that we've reached this point and I must say the second hundred of the episodes went much faster than the first one did. I'm hugely thankful to all the guests who've participated in those 200 episodes. It's all thanks to your willingness to share excellent fire science and research and engineering with others that allows me to produce this show, and I'm also hugely thankful to how far for their contribution in the podcast is our third year of partnership in this and and they truly are the the amazing force that enables me to to do this for all of you. So huge thanks to our farm and, of course, thanks to you listener. Whether it's your first episode of the fire science show ever or you've listened to all 200 of them, I'm super happy that you're willing to embark on this journey to learn fire science with me.

Wojciech Węgrzyński:

In podcast episodes like this, I I like to close some loops or at least revisit important topics. Actually, the last episode, 9199, we've also closed an important loop on timber. I've talked with Danny Hope and Luis Gonzalez-Avila from OFR on the Commercial Timber Guidebook and how stuff that we've discussed over the episodes of the podcast. As you know, research as growing body of knowledge that we had on timber turned into actionable document that really helps you design offices with mass timber. And in this episode episode 200, I'm trying to revisit the subject of facades and it's a subject that we've kind of started the podcast with. To do this I've went to London. I visited some good old friends at Imperial College London. I've talked to Professor Guillaume Reyn from the Imperial College London and to Dr Matt Bonner. He was a postdoctoral researcher at Imperial back then. Now he's at Trigon and we've discussed a topic that was kind of an Imperial ITB collaboration to really understand the testing methods and testing regimes on building facades.

Wojciech Węgrzyński:

It was kind of a crazy idea. If you could rank projects on craziness, I would rank this one very, very high. The idea was simple let's bring in five testing methods coming from different parts of the world Some big, some small, some having a corner, some being flat, some having a burner, others having a crib, some having a window, some do not. Let's mix them up and test five different types of facades over those five methods and just look at the consistency like just look on how those methods help us rank those facades. Because, if you think about it, it's kind of ridiculous.

Wojciech Węgrzyński:

Every country has their own facade testing standard. Every country seems to like them. There are attempts to unify those, but of course those are influenced by strong, let's say, political forces. As in fire research, it often happens and we don't seem to have a consensus on what's the best way to assess fire safety of a facade, and today, in a post-Grenfell world, it is a topic that bothers a lot of fire safety engineers. So in this episode we discussed the project. It was called Birgit, and Matt actually presented this at SFP Edinburgh, opening the pathway to have a podcast episode about it. Actually it won the Best Abstract Award and Matt gave it as a plenary talk. It was very well received. So I'm super happy to follow up on that with this podcast episode. There's a paper in the pipeline that explains everything that we talk in. It's not yet published but hopefully soon will be.

Wojciech Węgrzyński:

So as soon as that comes up I will let you know and in this podcast episode you'll learn about what we've done, why we have done it, what was the general idea of why this needed to be done, and we will discuss what can be learned from the small methods, what can be learned from the big ones, and, for me, the important part is the sweet spot, where you get the most knowledge out of your money spent on testing. So I think that's more than enough. I'm super happy to invite you for the 200th time to the intro. Let's spin it up and jump into the episode. Welcome to the Firesize Show. My name is Wojciech Wigrzyński and I will be your host.

Wojciech Węgrzyński:

The FireSense Show is into its third year of continued support from its sponsor, ofr Consultants, who are an independent, multi-award-winning fire engineering consultancy with a reputation for delivering innovative, safety-driven solutions. As the UK-leading independent fire risk consultancy, ofr's globally established team have developed a reputation for preeminent fire engineering expertise, with colleagues working across the world to help protect people, property and the planet. Established in the UK in 2016 as a start-up business by two highly experienced fire engineering consultants, the business continues to grow at a phenomenal rate, with offices across the country in eight locations, from Edinburgh to Bath, and plans for future expansions. If you're keen to find out more or join OFR Consultants during this exciting period of growth. Visit their website at ofrconsultantscom.

Wojciech Węgrzyński:

And now back to the episode. And even though we've started this remotely and that was 200 episodes ago Can you believe that that's a long journey? And, matt, we've started with facades, so we're coming back to the facade subject today. It's also a nice, like you know, closing a loop in the podcast. Anyway, we're talking about Burgett Project, something we've recently closed. The papers are in revision process, which will take 100 years, but eventually they will come up. But let's talk what brought us here. So, guillermo, you came to me with a crazy idea some time ago and, yeah, can you pitch it once again?

Guillermo Rein:

Yeah, this is truly a crazy idea. It's a crazy idea with a crazy founder and a crazy false start. So it's almost canceled twice. I was quite worried about this, but it didn't and we had here the dream team of why it went forward. So Matt put in their weight and Voge put in your weight. It was absolutely amazing, but it's a crazy idea. It's a crazy idea because it's in the context of what happened with the Grenfell Tower fire and everybody talking about facade fires but no one putting a solution forward. So the idea was to steer the community, to make them feel a little bit uncomfortable.

Guillermo Rein:

When you look into how facade tests are done around the world, most countries I think probably every country in the world actually does have a facade test. They might borrow from the British influence or from the American influence or from the Germanic influence or from the other influences, but it's fascinating that they all look so different. And when I mean different, I really really really mean different. You put them together and they hardly agree on anything except that they have a facade. The rest, the ignition source, the size, the shape, the configuration, not to talk about the criteria for passing it and the question is it cannot be that everybody's wrong, right. So some people have to be right. Some people have to be making sense of how they measure the facet. How do you figure this out? How do you figure out which tests make sense, which tests agree with each other, which tests are worth to put a significant amount of money into them and which ones can be put on the side for the time being?

Wojciech Węgrzyński:

I wonder, is a test meant to be an objective truth, or is it just a test? You know?

Guillermo Rein:

It's a test. But if you have 26 tests depending on the nation, not based on the laws of physics, not based on the technical knowledge of the nation, and the question is do they agree? Because if they agree amazing, they agree, there's agreement. We have 26 ways to answer the same question. Is that the case? Because before we do this study, no one could answer that question. Are the 26 wrong? Are the 26 right? Are 15 right? Are 3 right? I mean right in the sense of agreeing with each other. Obviously, we don't know why it's right or why it's wrong, but the question was agreement, and this is something that had already been done, but not with facadesades. Professor emmons in the 60s did this with flammability of panels and he showed that there was no agreement and that led to a new standard yeah, so I think maybe the framing was slight.

Matt Bonner:

Maybe I saw it as slightly different to that as in.

Guillermo Rein:

Obviously the premise is the same you don't like the right and wrong, but I wrote the proposal so I know why it's framing. Yeah, no, no exactly.

Matt Bonner:

Yeah, no, no, exactly. I'm saying how I approached it, not necessarily how we got the funding or what the purpose of the project was, but when we sat down, because basically the project was, we wanted to compare, as you say, different facade test standards. So in order to take the same facades, facades across a range of different amounts of fuel and different configurations are things that we expected to have kind of a different flammability performance, whatever that means. We can come back to that, but we expected the facades to have different performance. But we didn't know. You didn't know automatically. You might guess which ones might be better or worse, but you wouldn't be able to rank them, certainly looking at them. That would be an opinion, exactly, you'd have an opinion.

Guillermo Rein:

A desktop study, no desktop study. And then, fascinating, he knows, Bodger. You know because you have a testing facility. So what we saw and we saw this, Matt, in real time when we, before we approached you, Bodger, before I approached ITV we were a poor project because we didn't have too much money and we went to many different testing houses and one thing that happened when we were talking to the testing houses, we realized that the engineers in the testing house knew. They knew which facade would be more flammable or less flammable according to the standard they knew. The question is, how do they know? Not because they read the book, not because they wrote the paper, not because they ran the code, not because they have a computer model, not because they are mathematical geniuses is because they have seen the test so many times. They trained themselves, they became artificial intelligence learning machines and they could actually not explain to you why, but they could actually tell you the right results.

Matt Bonner:

So, yeah, I think this was the kind of the topic of my PhD and sort of the previous research we had done was kind of trying to look at. And this is how we started our collaboration with you, wojciech, and with IT. Itb was trying to see whether these tests, whether we could draw out the predictive mechanisms that were happening by people performing the tests, who could tell which facades would perform well and which wouldn't. Could we draw that out?

Matt Bonner:

Now, obviously, because of the nature of the collaborations and the data we were able to get hold of during the PhD, this was very weighted towards one particular test method, the one done at ITB, the Polish test method, and so this kind of was building on, because when we had a few examples in our PhD data set from the British standard BS8414 and from the American standard NFPA285, and we actually found, when we tried to compare the results of these tests and sort of combine them into one data set, that was really really difficult because they were all measuring different things. They seemed to be measuring somewhat the same thing, but trying to work out the sort of causal mechanisms behind that with the kind of data they were recording was very, very challenging. Yeah, and so there was sort of this question of like, well, why are they all different? What are they measuring? And so, to kind of step back a bit, guillermo came to when he presented this project to me. He came to me with this paper.

Guillermo Rein:

This is after your PhD.

Matt Bonner:

This is after my PhD yeah, this was me looking for work to do and Guillermo came forward with this project and showed me a paper from Professor Howard Emmons from 1968 called Fire Research Abroad, and in this paper there was other stuff in the paper, but part of it was he had done this kind of round-robin study where he'd asked six test houses around Europe to rank 24 materials in terms of their combustibility. He didn't define what that was, because at the time lots of people were using the phrase combustibility as if it had an inherent meaning, as if everyone agreed on this, that this material is more combustible than that material, obviously, except he was asking well, do we agree what that means? Can you tell me which of these 24 materials is more combustible? Can you rank them According to their national?

Guillermo Rein:

standards 24 materials is more combustible? Can you rank them According to their national standards? The standards existed.

Matt Bonner:

Yes, exactly. So each country had a standard around combustibility. And he went to these testing labs and said just tell me what the rank of these?

Guillermo Rein:

materials is and he got the materials and he sent the same material to each of the six labs.

Matt Bonner:

Exactly and they ranked them and the results were no better than random noise. They did not agree on which were more or less combustible.

Guillermo Rein:

And the materials? Do you remember some of the examples? One of them was plasterboard. I think it's the only one that people agree on it has no combustibility. I can't remember they were polymeric.

Matt Bonner:

In the figure. They don't label all the materials. It's like a separate bit in the paper where you have to read other things. So I don't remember it off the top of my head. But there was a lot of plastics. There were some organic polymers um as well, yeah, like wood and things like that. So it was quite a range of of stuff and some of them were the same kind of generic plastic, but in different forms as well. So it gets quite tricky, yeah, and some of them were thermoplastic, some of them thermosetting, so they charred or melted and all of that. And that's part of the challenge with defining combustibility right. And because of that, part of the outset of this was in Europe. They sort of tried to harmonise these standards and that's what ended up eventually becoming the European reaction to fire suite of tests which kind of define combustibility. It is quite arbitrary in a lot of ways. There is some. Some it did have a physical basis, but that's not the point of this episode and I'm sure you've got another episode of the podcast.

Matt Bonner:

This is where voychek will like link in the podcast description. But so we saw this and we went okay, we're in a similar situation right now with facades and that if we asked, I imagine, if we did this round robin study now and we asked everyone to rank facades in terms of their flammability, would countries agree or wouldn't they agree? Now, obviously we couldn't really, or we didn't have the funding or the ability, yeah, to talk to all these to ask people.

Guillermo Rein:

The original idea was to do exactly what MNs did with facades in Europe. Now the amount of money? No, we couldn't.

Matt Bonner:

Yes, that was infeasible and actually even trying to do what we did. So what we were trying to do was okay, can we just run all the experiments ourselves?

Wojciech Węgrzyński:

Realistically, you cannot send a bunch of facades across Europe to burn them down in multiple hubs. No, you could.

Wojciech Węgrzyński:

You could and unfortunately there's no other way to find out. I know you could, you could and unfortunately there's no other way to find out, because what we did with Matt in the Kresnik and in his PhD project, where we just took the results, purpose in mind, with the same solutions in mind, preferably by the same technical team, there's literally only one way to find out if, for the same sample, for the same type of facade and it sounds the same facade, but trust me, the Polish method facade built with a certain type of solution and be a standard facade of the same time of solutions, those are completely two different builds in terms of effort, scale, structure, amount of people involved. They just, they're just different. Right, it is even hard to say the same facade is just built from the same materials in this, with the same technical principles in mind, but you really have to put them in place and burn them down.

Matt Bonner:

And actually maybe to kind of highlight a particular example of this and something I've had discussions about at conferences, at places where I've presented our work so one of the things we had to decide when sort of setting up these facades because there are all these standards of very different sizes and scales was about do we include cavity barriers and, if so, where we had ventilated facades? And in some countries you would need those facades to have cavity barriers and quite often, if you're going to include them, you'd want to test them because that would give a more. You want to include them in the test because that would give a more favourable outcome. Of course, in these larger tests you are testing for in a way, they're trying to represent flame spread between multiple stories and they're considering the size of them is above one story.

Guillermo Rein:

Some of them do multiple stories. That's a beginning already. The size right. Some of them the ones that I might prefer actually cannot.

Matt Bonner:

So that was kind of my question is there was lots of ways you could maybe interpret, how you would even compare across these tests. So we did include cavity barriers in the larger tests and we basically aligned their position to the British one. We said, ok, the British one puts them at these heights, and those heights are chosen because they're where the thermocouples are. And the thermocouples are there because they're vaguely supposed to represent the height of a compartment and correlate with these previous tests. That happened in Canada in the 90s, and so there's all these historic reasons about why they are where they are and why the cavity barriers are where they are and other tests aren't correlated in the same way. So already we're kind of that's the thing. Like the test, the instrumentation of the other test isn't set up in the same location, wouldn't have the cavity barriers in the same location, of course. We then chose our own instrumentation location, so that's a bit different. But then with the smaller tests the question is do you include cavity barriers at all? And we didn't, because that's not the intent of those tests.

Matt Bonner:

When they're screening those facades they would not put cavity barriers in. They were. They're looking at kind of the flame spread over a kind of a sample of this or the flammability over a part of this facade. And I've been challenged already about like saying, oh well, shouldn't you include? Like, if you're not including cavity barriers, it's not really representative, because the fire is now impinging into your facade in a way that it might not in reality, but then again you're getting to this mistake of, oh well, these tests are supposed to represent reality in some way. Anyway, I was more bringing that up as an example of why this sort of idea of direct comparison. It's not as simple as in the material case with combustibility.

Wojciech Węgrzyński:

I can get the discussion a little, even a step back, because the first challenge was okay, we want to compare five facades, you want to rank them? Yeah, but how do you ensure that?

Guillermo Rein:

we chose five because then that's when the money ran out and really we went to 25, right. So I remember with matt we put them. Actually, with matt we put all the standards, what we wish to do, obviously way more than five, all the facades we wanted to do way more than five. And then it's like we wrote a line where, with you guys, we ran out of money and it was five on five.

Wojciech Węgrzyński:

I'm happy to do more If there's a founder listening who sees value in burning more.

Guillermo Rein:

I'm happy to burn more. I feel the audience might need to know the final five because actually we would have loved to have 20 of them.

Wojciech Węgrzyński:

Let's go with five tests and then let's talk to five types of wars.

Guillermo Rein:

What is important is there were many tests. How many tests was there in that review? 26, right? So we found I think there was 21 across the papers. So we wanted to choose within those 21,. Right, Because these are the ones that have been looked at already. We wanted to use countries that are relevant to the world but also relevant to us based in the UK, and we wanted to be different. We wanted to use countries that are relevant to the world but also relevant to us based in the UK, and we wanted to be different. We wanted to embrace diversity.

Guillermo Rein:

So, we didn't want to get five that are identical. No, we wanted to actually go across boards and immediately we found the POLIS test, which first you at United TV know how to do the POLIS test, but through the PhD thesis of Matt we developed a love for the POLIS test. We actually end up. Many people might not know about the PN test. We actually really like it. There's a lot of value in it, so obviously we keep it right. Then we have the ISO, which has in size a lot of similarities with the POLYS test.

Wojciech Węgrzyński:

Small ISO because there's also a big ISO. So we pick the two-meter tall one.

Guillermo Rein:

It's 2.8 meters already. It's taller than a person. It doesn't fit into a fire lab already. Again, we say small. We just want people to realize what we mean by small. Then we have the NFPA. Of course we cannot go without the Americans. American is a very influential type of way of thinking and is adopted in many other countries that might not actually have a standard otherwise. So the American one is very strange because it's just two stories with two compartments. And an external burner in addition to yeah with two different English sources.

Matt Bonner:

Well, I'd also say, part of the choice of the Polish, the American and you're about to mention the British one as well was that we had data from my PhD and we had performance stuff, we had knowledge and there was availability to compare stuff in the literature. And similarly with the other two, we chose which Guillermo is about to explain the ISO and the German one. That was again about comparison with other data and we knew the European harmonized standard was being worked on at the same time as well. So this was about trying to choose the ones that would be most able to have comparison with other things in the scientific.

Guillermo Rein:

yeah, okay, the bigger ones so you know I I want to recap. So we have the police, one is 2.5 meters. We have the small iso 2.8 meters tall. The nfba is five meters, more than 5.3 meters.

Guillermo Rein:

These are already constructions, right yeah we definitely need an itv kind of testing site. It doesn't go anywhere else. Then we went to the D, the German. The German is very influential, especially because most German engineers are very proud of it. So the D is already more than 5.5 meters tall and it has a corner configuration, which is actually a configuration that has a lot of merit, because then it radiates to each other, the two panels, and then you have the British one, which is a corner test as well, and it's the tallest of them all, which is it goes to 8.9 meters. Right, this is a proper wall of a building, right.

Wojciech Węgrzyński:

It is massive.

Guillermo Rein:

And it's fascinating when you put them all together. There's one of the figures in the paper and in the presentation of Matt is how different they look already just by putting them together. The same scale. Not just only that the way the barriers go and the ignition sources and the criteria and the tiny details, the big details already could not be more different. And yet Polish people, international level, american people, german people and British people, they receive their protection of the environment and the safety of the environment through these standards. And we are in a context where the Grenfell Tower we know that the market and the regulation was not working. So the question is could this be one of the reasons, this disagreement in the way they want to measure and test facades? Could this be part of a disarray in the market and the regulation?

Wojciech Węgrzyński:

Okay, and so those were the five testing methods, and we also burned down five types of solutions. My question that I asked before, but I'll reiterate how do you actually compare five different like, if you want to compare five different facades, how do you make it fair play? You know, I could build an extremely heavy let's say, timber facade and compare it to a thin aluminum foil, and the aluminum foil will probably fail, even though it's not combustible. So how did you make it for play, matt? Because I know there was a lot of engineering in that as well.

Matt Bonner:

Yeah, I think this was a tricky question and again we were kind of trying to base it on the previous research we'd done in the PhD and the lessons we learned there.

Guillermo Rein:

The lessons learned from the research, not the research itself. Exactly exactly. What I mean is that I'm trying to paraphrase that. This previous knowledge, this project, didn't start with us playing with Lego. No, the team had knowledge and this was used to launch to the next step.

Matt Bonner:

Yes, exactly, but also the knowledge was quite a course level and so that was what we're sort of carrying over, in the sense that we've been able to identify that in the research we've done before. Across all these three different test sets we had only three types of facades were tested in 95% of cases, which are the rain screen facades, which is where you've got a ventilated cavity and some external cladding, ethics facades or EIFs, whatever.

Matt Bonner:

The other one is facades which is like render facade systems, where you've got some insulation and then some render which is kind of fixed to a substrate not ventilated, and then the last one is sandwich panels, which were and of those it was more common in our data set to see ethics facades and rainscreen systems in our data set to see ethics facades and rain screen systems. The other thing that gets chosen very commonly is curtain walls, but of course curtain walls aren't really flammable in the same way. In general People argue about this but they're not really tested in these tests looking for flammability facade systems. So that was the first thing. We were kind of like OK, we have these three types of facades and of the ones we see, the most common are rain screen and ethics. So that was where we started and we also realized that actually when we looked into it deeper, in general we found so only a very small proportion of the data, as the facades we looked at in our phd kind of failed these tests or performed badly in these tests, supported the spread of flame, and the ones ones that did needed it kind of seems obvious needed some sort of combustible material, some source of fuel, and it was a lot more common to fail if they also had a ventilated cavity. So we're like right, we think rain screen facades are going to perform worse than ethics facades, and we also think that the more combustible material you have, the more likely there's going to be flame spread, and so we tried to kind of cover that range. We had an order to our facades of how we had a predictive ranking for these. So we had two ethics facades, one that used mineral wool insulation and one that used EPS insulation. That's very common insulation for these kind of facades and so there's an obvious ranking there. You think the one with no fuel in it, that was kind of just a control. We assumed that all the tests would rank that the same and rank that as the best one.

Matt Bonner:

Then, after the ethics ones, we then had three rain screen facades, and so in the rain screen these can get very complicated. On real buildings there can be a lot in the build-up. We were kind of keeping it to this kind of essentialised rain screen facade, which was you just had some cladding, a ventilated cavity and then some insulation fixed to your testing substrate. In this case what we are varying between these three facades is we had one that had non-combustible cladding and combustible insulation, one that had combustible cladding but non-combustible insulation and one that had combustible cladding and combustible insulation. So you can see that those three cases have kind of increasing amounts of fuel. So because the cladding's thinner, it actually provides less fuel, but obviously it's also on the outside, so possibly more exposed to fire, to the sort of impinging flames, and so it wasn't really clear exactly what the ranking of those three would be. We would imagine they'd perform worse than the.

Guillermo Rein:

It's very important. We talk a lot of people. Everybody had an opinion. I thought this was absolutely fascinating. Everybody had an opinion. I thought this was absolutely fascinating. Everybody had an opinion. Some people raised some technical knowledge, some people have been talking to their friends, some people have been reading books. Everybody has an opinion. You show this table of these five facades and the discussion would be for hours and hours and hours. I'm unprofessional. What we wanted was to provide the evidence, not the opinions, not the. I think. I feel I thought it's like the evidence. This was the objective of the project.

Wojciech Węgrzyński:

And the amount of combustible material was kind of normalized by the U-value of the facade. So it was not based on some unrealistic case. Oh, we're going to put like 20 centimeters of EPS now because it's better when it's thicker. No, they were normalized to provide the same U-value.

Guillermo Rein:

U-value is the resistance to heat for insulation of a building.

Wojciech Węgrzyński:

Yeah, so this is.

Guillermo Rein:

Which is the reason why we have facades. Exactly, yeah.

Wojciech Węgrzyński:

Exactly that's one of the major points right now, why you would put EPS on the exterior of your building. You want it to insulate better.

Matt Bonner:

It's worth saying that we actually used a relatively high U-value, so not as much insulation as you'd use on a real building, and that was partially for cost-saving and partially for safety reasons, just so that we wanted to keep the fires within manageable lab conditions.

Wojciech Węgrzyński:

Thank you, matt, I really appreciate that.

Guillermo Rein:

It's important because we didn't go. One of the five is not the most flammable facade that everybody's worried about. It's actually so flammable that it's actually forbidden in the UK, for example, because we were afraid that it would overwhelm the testing facilities. It would I tell you this? Because when I go around the world telling people that are not fire experts and they don't visit very often our conferences they are fascinated by that detail that the testing lab already knows. Oh, I don't test that one.

Wojciech Węgrzyński:

No, I'm not testing that one.

Guillermo Rein:

It's like well, if they knew. Why is it that the market didn't know?

Wojciech Węgrzyński:

No, no, guillermo. The sad part is, the market does as well.

Guillermo Rein:

The sad part is the market does as well. The sad part is that exactly.

Wojciech Węgrzyński:

But let's not go there.

Guillermo Rein:

Anyway you place your order and I'm left with buying 25 facades, Sorry context, it's very important One of the two false starts of this project, the two difficulties that we had to overcome. The last one is that this happened in the middle of the lockdowns of the pandemic, of the COVID-19 pandemic, so which means that this project was literally all on Zoom and phone calls and emails and remote testing and obviously success story, massive success story, but it was really hard.

Wojciech Węgrzyński:

Yeah, yeah, and it took us a lot of time to actually take your ideas and turn them into designs. And of course I'm a Polish lab. I can do as many Polish tests as you like, but if you ask me to do a British standard test for you, I don't really have the rig, you know. So I had to build one, and I had to build the NFPA one and I had to build the DIN one. So in the end they were not the most perfect rigs that you would have in testing houses for testing houses, who just run them as run-of-the-mill tests.

Guillermo Rein:

And NFPA, dean and BS are very upset with you because you didn't build the perfect, of course, of course. No, it was very professional. What I mean is a joke. Is that, yeah, and we are exposed to this. We are exposed to this. Some of the listeners already have this. Everybody has opinions on this, everybody. Some of the listeners already have this. Everybody has opinions on this. Everybody has opinions. Oh, you chose the barriers wrong. Oh, you chose the wrong facade. You did wrong the thermocouple location. We can have thousands and millions of hours of discussions about the tiny details, but let's focus on the big details. One of them is almost 10 meters tall.

Matt Bonner:

The other one is one meter tall. I think the key thing is that we did realize that we wouldn't be exactly matching by building thing is that we did realize that there we wouldn't be exactly matching. By building our own system we wouldn't be exactly matching these standards. We didn't have the time to be like certified each one, we didn't have the budget to do that. We did actually look but you know we went out for tender with this project. We didn't automatically uh, itb was bought in as a collaborator nobody tell them what happened when we went to tender.

Matt Bonner:

Oh, it was extremely, extremely expensive.

Guillermo Rein:

It would have cost, it was 10 to 100 times bigger budget than we had Right.

Matt Bonner:

And it was. Yeah, it definitely would have cost probably five times the amount at least. Okay, Anyway, it was a lot of money to do these by a sort of test certified rig, as it were, for these larger tests. But the key thing is we're not interested in and I think a lot of the reason I have people who have challenged me at conferences and stuff is because it's people from manufacturers or people or testing houses who are like worrying that we're trying to compare these tests or rank these tests, no we are trying to compare the tests.

Matt Bonner:

But the idea is we're not coming away to say this one's the best one, this one's the worst one. That wasn't the point. What we're trying to say is are they consistent? And the consistency is going to depend a lot more on these big differences, like if the consistency, if it is as important as those tiny, tiny little details that we might have got wrong. If that's what's affecting the consistency, then you know that's already a finding.

Guillermo Rein:

Yeah, exactly, this is very, very important because we are discussing all the details, and even more than they are. If the final classification of a test of a facade or any material depends on tiny little details, I say that a standard is not useful and also look, the new European method is in development.

Wojciech Węgrzyński:

Right, you brought some tiny details about cavity barriers. They are tiny details really. Guillermo brought the corner configuration. He said it matters a lot if there's a corner. No, no, I said it's interesting. It's interesting, but it matters because they re-radiate. There's details around windows, there are details about the connectors, there are details about what you do at the end of your building, at the top of your building. There's so many tiny little technical details and if those tiny little details can change something from very good to very bad, then we have a very big problem.

Guillermo Rein:

We have a big problem. We should not be using that as standard.

Wojciech Węgrzyński:

Yeah exactly that's where I found a lot of joy in this project to actually standardize my details. I did everything the same. That was the first time where we could, as a laboratory you said we build up the knowledge base, so we also build a 25-experiment knowledge base, now more. But it was the first time where we had a chance to actually do the Polish test method and build the exact same facade in the exact same way, in a much bigger way, and see what happens First time ever, because I saw smaller tests. I saw larger tests it was never the same exact type of construction that I had control over the tiny details. It was very important for us and I would like to Sorry, I want to say something.

Guillermo Rein:

It will probably cause a stir in the academics in the audience, but it's not the first time that you saw this, boji. This is the first time that it's been done. Yeah, okay, in the wall and it's unacceptable that it has to happen in 2022. Yeah, it should have happened decades ago that it has to happen in 2022.

Wojciech Węgrzyński:

It should have happened decades ago. Yeah, perhaps when we were starting thinking about standardizing stuff. Well, I had episodes about you brought up SBI and the Euroclass system and Van Muelen told me that facades were next to be standardized. It just never happened. So it should have happened 20 years ago. Anyway, I wanted to bring in Jakub because Jakub Bielaski from ITB. He participated in this with me. He was an immense support and he's probably the only one who saw all 25, because I think I've missed one or two days of the small elements testing. So Jakub probably has even more on-hand experience than me on testing those. From our perspective it was very interesting and I don't know. Maybe let's go through the results briefly or what we found briefly, and then I'll tell you my experience about doing them, because I think it's an interesting context to the findings themselves. Let's try and briefly cover how did these facades behave? Can you give us a five, five minute executive?

Matt Bonner:

update, matt.

Matt Bonner:

So I think, starting from a purely qualitative explanation, I think what was interesting is, if you just looked at the videos of these tests, you could see that in general, the qualitative behavior was quite consistent, in the sense of pretty much all of the rain screen facades promoted flame spread in every test, more than the ethics Well, more than the ethics and in fact the ethics facades, because of and this was a challenge with measurement it's very difficult to see actually whether spread is happening behind the render or not.

Matt Bonner:

Only in one of the experiments did the flaming break through the render to the outside, so it was visible, um, and we can actually we'll circle back around to that, but in general you could see this trend of like okay, they're all supporting flame spread, the insulation versus the cladding. That was very difficult to distinguish, just without going into sort of quantitative analysis, uh, the difference. But you could see that the one that had both of them was noticeably the worst one, which is what you'd expect, but also that, uh, in all three of those rain screen facade cases, they all supported flame spread to the point where you'd be like that you probably don't want to see that on a building, you know yeah, that's bad yeah yeah, so you're only able to distinguish the sort of ranking stuff once you sort of dived into the quantitative analysis with them.

Matt Bonner:

However, while we're still at the qualitative level, that was the good news.

Guillermo Rein:

That was the good news. The good news is there was some level of agreement. Yes, this is good news and I want to highlight this we didn't know this ahead of time. We actually maybe we were right in the hypothesis that there was no agreement like M168. And now that this is public and a scientific discovery, people can use this. It's not an opinion now. Now it's evidence. There is a level, a level of agreement.

Matt Bonner:

Yes. But I think what was interesting is you could notice some kind of key. You notice that actually the sort of details of this behavior was quite dependent on these small details of the test. So for instance, because of the size of the Polish and ISO tests, because they don't have cavity barriers, they've got open top to the test, you actually kind of get a, rather than having, like flaming within your cavity, the flame spread within the cavity. You don't really even have flame spread in your cavity. What happens is the stuff that pyrolyzed in the cavity just goes to the top of the facade and then burns at the top.

Guillermo Rein:

It becomes a reactor. More than flame spread.

Matt Bonner:

So, rather than flame spread, or seeing like there is eventually flame spread on the surface of your facade, or flame spread in a more traditional definition of flame spread. But it's not really. You don't see flame spread. What you see is at some point you suddenly get flaming at the top of your cavity.

Guillermo Rein:

The flame is too large in a small cavity, sorry, in a small rig, to see flame spread.

Wojciech Węgrzyński:

Yes, whereas because you're all this because you've seen it in the bigger ones you can see flame you could argue that if it exited the sample, that if there was a continuity, it would have to burn above that. So all you can say that there was flaming above two meters and it would have burned in the cavity if the cavity existed beyond it. But you're not able to capture, like, how far would it go?

Guillermo Rein:

There's no need to see flame spread in the small ones. There's not. It's just that it's true that you don't see flame spread in the small ones because they're small I mean, they have three meters tall, um but in the big ones that means they're still.

Matt Bonner:

You can actually see yeah, you kind of, in a way, you almost see ignition, because it's like the point at which it is very soon very soon after things reach ignition.

Matt Bonner:

You'll get ignition at the top of this facade. So there's that and there was also also in the corner. You noticed in the ones with or we noticed in the ones with the corner test, you kind of got this kind of behavior where, again, you kind of got this transition behavior of like, as things were heating up, you'd get kind of the accumulation of gases around the corner and then you'd get a point where, oh, you got a sudden transition of quite a lot of flaming around some point in the corner you get a very sudden flame spread. Again, this couldn't really be captured in metrics very easily because these aren't flame spread in the way we traditionally talk about flame spread in theories around fire safety. But these were things you could see and describe qualitatively.

Matt Bonner:

And the final one, which is a really interesting one this sort of comes back into this discussion about consistency is so when I talked about this ethics facade, we had one test where it actually broke through. The flaming broke through to the outside of this facade. That was actually the ISO 137851 test, this really small scale test. It's like why is that one the one that performed worst for these facades? And what happened in this test is. It's the only one of the five standards we looked at where the facade is actually raised up above the ground and above the burner. And because EPS is a thermoplastic material, it melts. The melted plastic dripped down to beneath the facade formed a pool fire, and then that pool fire ended up igniting the corner of this facade, and that's bad. That's a scenario.

Guillermo Rein:

I mean bad is unsafe, right, it's not a flaw of the test. Actually, it's actually good of the test that they allowed us to see the pool fire.

Matt Bonner:

And that's something that couldn't have occurred in the other tests, and people have gone. Oh well, is that something that could occur in real life? And you're like, well, maybe on a balcony, if you've got this above a thing, I don't know.

Guillermo Rein:

No, but in general terms, the fact that fuel in liquid form is moving somewhere else, as a fire engineer, that's not good.

Matt Bonner:

Right, but the challenge of this is then when we come to the next part, we might stand this bit longer. But when we come to the quantitative element of it, and how do you rank these and how do you analyze these quantitatively? This doesn't really fit into any. You can't really fit this into an obvious metric. You can't obviously quantify this.

Guillermo Rein:

No, you can quantify it. What you mean is that then there is no agreement, you can create metrics and standards and indices, but then they don't agree with it. That's when the disagreement starts to happen.

Matt Bonner:

Right, yeah, there's no obvious one of like oh, this is what flammability means, or this is what this means, according to all of them. Yeah.

Guillermo Rein:

If you only stay with one. Imagine that you and I just do British because we are in the UK. Then we might find agreement within the British standard, but then when you move to other standards, that disagreement starts to disappear.

Matt Bonner:

This is what you're saying yes, exactly, we can maybe go on to that, but I want to just open to in case you want to add anything more.

Wojciech Węgrzyński:

While we're on the qualitative aspects of what we saw, One thing when you assess those things in the lab, the point is that the client doesn't come to because they're very interested scientifically on what their facade does. They want to have a certificate. And to have a certificate or some sort of proof of passing detail, you have to first assess the failed pass.

Guillermo Rein:

So so maybe you can comment on on the failed pass, like how many of them failed or not well, but that depends on the national criteria, which is a different, yes, but if we didn't really cover that in the paper because that's, but that depends on the national criteria, which is a different? Yes, but if one. We didn't really cover that in the paper because that's something else.

Wojciech Węgrzyński:

Well, we kind of did.

Guillermo Rein:

Well, we tried, but that's the opinionated part of the project, because each country has a different rig and a different criteria.

Wojciech Węgrzyński:

I know and I know, but if a facade passes in three countries and fails in two others, then Well, part of the challenge as well is that these don't all have the same.

Matt Bonner:

So, as we were saying before, there's 21 test standards, but there's more than 21 countries using the 21 test standards, and so, yes, while the standards may be the same, the criteria that gets used isn't always the same, um, so, there are like 21 rigs and maybe there are like 200 criteria.

Matt Bonner:

Right and the ISO 137851 test. The screening is mainly used as a screening test, so it's not intended to be used necessarily as a standard that you would apply, pass or fail to. Having said that, apparently in our research it is used as a standard in the czech republic, I think, um, I saw it's even bigger than the, the police, and the police is used for regulations I'm just talking about when you're trying to compare these with in terms of like pass fail.

Matt Bonner:

It depends on whose pass failure criteria you use. So we did try and compare them in our paper and actually we were quite generous because we kind of invented our own pass fail criteria you use. So we did try and compare them in our paper and actually we were quite generous because we kind of invented our own pass fail criteria for the ISO standard. Because if you used I wasn't I did find some examples of what the Czech ones apparently were the failure criteria. But if you applied them, even the mineral wool facade, the mineral ethics facade, failed, according to the temperature thing.

Guillermo Rein:

So I was like that's not in the paper and it's gonna get very complicated it's in the paper but or currently it's in review we'll see whether it gets through reviews, but there is a table on it.

Matt Bonner:

But anyway, what we found is there was some consistency in which ones passed and fail for sure. But the quantity, when we were sort of quantitatively measuring consistency, it wasn't like it wasn't suddenly a hundred percent consistent.

Guillermo Rein:

There was still some, some inconsistency no, no, but definitely not a hundred percent. But you can actually quantify.

Matt Bonner:

You have metrics of correlation but this is where it gets really tricky because essentially and this is the problem with we've got quite a small sample size with 25. We've got 25 tests and the degrees of freedom on the pass and failure. Things are only it's kind of like a binary thing and so the metric of consistency for the pass fail isn't quite the same as the metric of consistency for ranking and it gets very tricky, and this is why you should probably read the paper for the competitive part of it.

Guillermo Rein:

It becomes very muddy and it becomes actually opinionated. This is the part of the paper that I would prefer to move less the emphasis. The answer is there is agreement across the standards for these five facades in the broad sense, in the very broad sense, you as a person say, oh, that's a big fire, oh, that's a small fire. Good, when you go into, oh, I'm a fire engineer, I'm a fire scientist, I can actually tell you flame spread, heat release, rate, damage. That's when there is no agreement and it's important they don't agree on, not just on the fine details. They don't agree on the non-broad details. That is very interesting. They agree broadly. They disagree on anything else, but don't forget, one of them is small, the smallest one is very small, the largest is very large.

Guillermo Rein:

In terms of money, this is really really, really important for the project In terms of the effort that one has to do to test we're talking about orders of magnitude difference in the cost in time, in an effort that one has to put to use the judgments which are NFPA, dean and BT standards, and there is a small effort to put in the small ones which are the POLIS and the ISO. It means that with the same amount of money to understand your facade, to understand the safety of the product that someone is selling. With some of the small tests, you can do hundreds of tests and truly understand all the little details of what is happening. With the monster ones, you can only do one test.

Matt Bonner:

You were saying to us before we started recording. I think that the wood crib from the BS8414, the wood crib from one of those tests costs more than running three of the Polish tests.

Wojciech Węgrzyński:

We either have very expensive timber or very cheap laboratory. But that, unfortunately, is the truth. It does indeed, and I also. Maybe you remember that, matt, but just shortly before COVID, when we were burning the facades for one of the chapters of your PhD, like you came to my lab. We were burning like five in the morning, like literally we were doing five tests in the morning. Then we were going for lunch and the technicians were cleaning up the lab after the five burns, and by cleaning I mean they were tearing down the old facades from the rigs, the walls.

Guillermo Rein:

It was the polystain there.

Wojciech Węgrzyński:

The polystain yeah, the small walls. So the walls it was the polystandard. The polystandard yeah, the small walls. So they were clearing the walls, attaching new facades to the walls. So when we came back from the launch and it was not extremely long we had three more facades to burn before the evening.

Guillermo Rein:

Eight tests a day, and then you describe the amount of productivity in one day with the polystandard. How would that work with the British one, jesus?

Wojciech Węgrzyński:

Christ, it's incomparable. Like to build a facade for the big rig first. It's over eight meters tall. I need a scaffolding or a lift Scaffolding. You need to have a person certified that. You need three people working two upstairs, one on the bottom to build it up. You need three people to instrument the facade it. It takes you more than one day of work to just put the thermocouples in in the correct location.

Guillermo Rein:

So one day for thermocouples? How many days to put the facade?

Wojciech Węgrzyński:

it's a week no, no, two, two days probably, maybe three days if it's really complicated, maybe one day if it's super simple. But but you measure that in days. Then the fire itself is so big you cannot do anything else in the lab if you're doing that indoors because it's huge. So you'll need a team of five, six people running the test itself for safety. So you run the test. That probably takes you an entire day of the lab to run the test. It's unlikely you're going to have three or four rigs of that scale. You're not going to build three of them. So, realistically, you're burning the thing. It takes you many hours to cool down, you're not taking stuff out of a very hot wall and the crib is smoldering for many hours after the test. It's super annoying and then you need two days to clean up the stuff. So I would say, if you have Two weeks, I think If you are optimized for testing that thing and that thing, only you could run one a week. That's it.

Guillermo Rein:

One a week high intensity High intensity.

Guillermo Rein:

And the effort, this effort that we're describing, it's just the time. It's not that we don't have patience Experimental people have a lot of patience, like you, boji is that there's the cost associated to it. Yes, no material that you have to store in the lab to do one experiment for a week. The amount of people that you have to have the team around, right, the debris that has to be collected and has to be put somewhere else, whereas in one day you could do many Eight, easily, okay. So as an engineer, as a scientist, I can learn so much from having one complex facade analyzed a hundred times in different situations and with repeats and different questions, and I cannot learn much from one single shot experiment.

Matt Bonner:

I'd like to add on that, because I think we go to all that work with these tests of making this huge, huge test rig and it's so you know it costs so much money and then actually what gets measured as well in these tests is then like some thermocouple measurements at two heights, some very coarse measurements and like some videos. And if you just think I mean, even for these tests I don't want to say there was a reason we chose to do these experiments and there's's a good reason why we want to open this to discussion. But honestly, if you think of the budget to perform that mostly went on doing these large-scale experiments, if we had done that amount of money's worth of smaller experiments and really kind of delved into varying these and working on the thing it could have probably generated a lot more knowledge about how facade fires work.

Guillermo Rein:

I've done that for you, but this is important. That's why we have to go through the pain of including the dean, the NFPA and the British Standard, because it has not been done before, because people have wished to do it. Could not do it for all the barriers that we have to go through. The first one is the funding and then the time. Do it, could not do it with all the barriers that we have to go through. The first one is the funding, and then the time, and then the facility, and then all the pain. Right. I feel sad that fine engineering and fine science has to wait so long to do something that is obvious the market should have done decades ago.

Wojciech Węgrzyński:

To be fair in terms of efficiency the NFPA rig is built for efficiency, so NFPA rig is built like a furnace. Efficiency the NFPA rig is built for efficiency, so NFPA rig is built like a furnace. It has a movable attachment wall, which we didn't. That's why our rig was a little different than the NFPA rig, because we didn't have the movable attachment wall. Because I'm not going to build that for an ad hoc test rig, right, but in normal lab you would have a movable wall. So you build a wall outside of the rig, you just bring it to the rig, burn it down, take it down.

Wojciech Węgrzyński:

Another one it's a gas burner also there we we had gas burner in din. Gas burner versus script that's a very interesting discussion and then perhaps we were not in time to talk about it today but also the the heat exposure in those tests. It was different and it was also something that we've studied. So so some of the tests are built for repeatability, but there's like there is this much you can do if your facade is nine meters tall and so much more you can do when it's two and a half meters tall. The question is, do you get more answers from just it being nine meters tall?

Guillermo Rein:

You definitely get an answer which is different. So there is value. There is value in the big rigs and this is something that actually Matt has 100% taught me in this study. There is value in this. They are expensive, they are months of that difficult, but they do actually provide some sort of answers and there is value in them. Right? Maybe I'm personally inclined to the smaller ones because they can give answers much faster and much more flexible. But what I worry about is how many people are thinking this way. How many people are thinking what is the rig that will help me the most to understand the product that I'm selling? Which is the rig that will answer the worries that I have about the safety of facades in buildings? And they don't think like this. They say no, they feel entrained. It's like no matter that my product is being sold across different countries. I am not going to be comparing what different countries are saying about my product. I'm just going to be quiet about this.

Wojciech Węgrzyński:

One more thing that I can bring in. If you put yourself into the shoes of an engineer who's engineering a building and they have a limited choice of tools they can use to figure out more about the solution there like to reassure that it's fire safe you can perhaps perform a desktop study, which is an expert judgment. I once taught desktop studies. You know it's like a cone calorimeter because it sits on a desk. It's a small device. That's a desktop study for me, boy was I wrong.

Guillermo Rein:

You might want to explain what a desktop study is Very controversial.

Wojciech Węgrzyński:

It's a person sitting at the desk doing a study and after the study they give an opinion.

Guillermo Rein:

It's an opinion, which is fine to give opinions, but I just want to say, as a far scientist, there is no theory, model or experimental series that can support that opinion.

Wojciech Węgrzyński:

Yeah, yeah, I know, it was shocking for me to find out, but anyway, you can do that. You can do some sort of simulations. You can perhaps do a smaller screening test like a Polish or ISO one. Like, if I compare the cost of the Polish test method versus the cost of simulation and knowing Simulation.

Guillermo Rein:

you mean computer simulation. Computer simulation and knowing, yeah, but you mean computer simulation, computer simulation and knowing, yeah, but it has to be validated.

Wojciech Węgrzyński:

I know, guillermo, but some people would do that and knowing roughly how much it costs of a desktop study, they're in the same bracket of costs, more or less. I would even risk saying that the test method is cheaper than the simulation study. If you would like to have a good one, you probably cannot because there's no validated method for that. But if you just want something to strengthen your opinion on the subject, I would say that using those cheaper, smaller tests to the advantage of an engineer is a brilliant way to engineer to support you in your decision-making. Perhaps we'll have a machine learning tool, perhaps we'll have some sort of clever tool in the future that will help you do that. But today, if you're designing a building and you're uncomfortable with the design because there are too many unknowns in the design that you feel those uncertainties need to be addressed, testing is not just for manufacturers. I see value and this paper also shows that you can learn most of the stuff from the stuff that doesn't cost that much.

Matt Bonner:

I was going to say so. I recently presented this work in Edinburgh Award-winning.

Wojciech Węgrzyński:

Award-winning hey.

Matt Bonner:

Yeah, thank you Won the top abstract award at the SAP Europe conference in Edinburgh. But when I was presenting this work I top abstract award at the uh sap europe conference in edinburgh. But when I was presented this work I sort of mentioned at the end with these test standards when I so in the discussion I've had, I've discussed with a lot of fire engineers and fire scientists over the last few years of doing this work.

Matt Bonner:

Um had a lot of informal arguments, discussions, sometimes over drinks, but the thing is it generally, people generally come up with three reasons as to why they think these tests are done right. What are the point of these tests? Either they they think these tests are. Oh, these tests are providing a pass or a fail. They tell you if your facade is safe or not to put in a building. So it's like these tests need to basically be so representative or so good that if you pass this in one particular range of enrichment, suddenly that facade and also all the variations where you suddenly have a window or you have a little opening in it, or now it's at a corner you know all of the ways your facades can vary on your building just doing that test guarantees that that's safe. I think that's quite unrealistic, that particular view.

Guillermo Rein:

Don't say unrealistic, because that's what they are aiming for. That's not helpful, maybe.

Matt Bonner:

Yeah, I think that view is not helpful in the sense of like yeah, I don't mean the test is unrealistic, I just mean like I think, imagining that one test could somehow tell you like oh it's passed or it's failed. I think that's not realistic or not true, and it's not what tests do Exactly?

Guillermo Rein:

Of any test mechanical engineering, chemistry.

Matt Bonner:

So then there's these two other things. Are these tests to sort of rank the relative performance of different facade systems? So you're just trying to say, okay, this facade is worse than this one, and actually that's kind of how the combustibility?

Wojciech Węgrzyński:

That's the market ladder.

Matt Bonner:

That's how the combustibility rankings work, in a way.

Wojciech Węgrzyński:

I would say it's mainly a ranking system.

Guillermo Rein:

Yeah, yeah, yeah, yeah, yeah but this is fascinating because most people don't know this.

Matt Bonner:

So either it's ranking relative performance facades against different systems, because this is kind of how combustibility works as well, like when they were coming up with the combustibility classes, they were picking, they were, they were choosing reference materials which they're like we're kind of happy with this material we're not happy with this material, so we want to see how other materials perform compared to them.

Matt Bonner:

So that's a way of doing it and you know if you're using that. That's kind of what we're saying with, like, actually they're relatively consistent in ranking, depending on what metrics you use for ranking and how you choose to do that ranking. That could be quite a sensible approach, but of course that doesn't match with this kind of idea of just getting a pass or a fail. You need more of ranks associated with it.

Matt Bonner:

But then there's this third one, which comes up a lot and it's kind of what you were saying there, wojciech of actually these tests are tools to be supported by a competent person, to then extrapolate from them to some sort the ideal of how we'd like to be doing fire engineering, but also, I think, with the data available right now, the sort of experimental data available right now, with the knowledge as well, the theory available right now, we don't really have the ability to do that beyond.

Matt Bonner:

You know, some really sort of rough assumptions and judgments, some really sort of rough assumptions and judgments. So, yeah, I think, if we want to take that approach, which I think is really beautiful, I think we need a lot more of a body of theory, or a body as well, of like large tests and this was kind of where my PhD was around either this kind of top-down approach where you have loads and a big database of lots and lots of test data enough that you can just kind of extrapolate based on judgment because you've seen enough tests, or enough kind of different kinds of tests as well, not just like one test method for the reasons we talked about before that you can kind of see how a facade will behave across lots of different scenarios, or you have developed the theory enough that you can kind of predict from fundamentals what will happen. I think both of those need to expand.

Guillermo Rein:

Yeah, and all those three uses of tests in general is quite meaningful. Thank you for that. So your final thoughts.

Guillermo Rein:

My final thought is that the paper has news or information for different stakeholders. I would love this paper to be debate ground for fire engineers. I think fire engineers have been having a lot of conversations, having beers, but they have not having enough professional conversations together and maybe this paper and the controversy that it comes with and the disagreement and the agreements with it can actually help that conversation happening. There is also a value, I see, for authorities. Authorities need to harmonize because if authorities don't harmonize, they're creating the possibility to game the system.

Guillermo Rein:

If everybody has a different rig, everybody has a different criteria, you are going to end up with different manufacturers doing different things and obviously some of them are going to be unsafe and some of them are going to be unsafe. So harmonize. It is extremely painful to harmonize, especially at a multinational level, but there is an incredible amount of value for the safety of your citizens if you harmonize, because then manufacturers cannot game the system. And and the third one is to the manufacturers to manufacturers, who are actually making money out of their products and they're providing a service to society they need to make sure that they themselves, not just the regulator they are selling a safe product. Before you go to market. You might want to learn how your facade is behaving not because you have to, but because you should and there is value in exploring which rig you want. That will give you more information about the product you are selling.

Wojciech Węgrzyński:

Yeah, beautiful.

Guillermo Rein:

Unfortunately I don't think there is many value in the paper for testing houses. Maybe you can extract something. No, no. Normal testing. You are not a normal testing house. I'm definitely not a normal testing house.

Wojciech Węgrzyński:

I'm definitely not a normal testing house, I hope In a positive way, I hope.

Guillermo Rein:

In a very positive way.

Wojciech Węgrzyński:

But I put that 10 years ago, I think. I had a paper where I said that there's a space for performance-based testing and a testing house that can play a little different role in the future and also, you know, kind of Ruben's ERC project is also. I like this job and I like burning stuff for a lot of money for people, but it is sometimes painful when you know you could learn more. You know, and if you could maximize knowledge per euro spent on the testing, I would be very happy and I think it would be good for the business of testing house. So therefore, I see value From this paper, from this paper indeed and yeah, let's hope the reviewer too is listening to the podcast and they've took some of the considerations and brought in here as an answer to the comments. So thank you, gentlemen, for this.

Guillermo Rein:

Thank you. Thank you, budi, it was great.

Matt Bonner:

Thank you, matt, thank you so much.

Wojciech Węgrzyński:

And that's it. Thank you for listening. Challenging project done with some good friends, some really good engineering out there and really for the testing house. It was quite stressful to run this project but we've somehow managed to and I'm really happy that now it reaches the daylight and engineers worldwide can benefit from our findings. I think it was interesting just to burn those facades, just to look at them, just to compare those facades, you know, just to look at them, just to compare those methods. It was an interesting experience and I think it kind of gives me this sense of unease that is there really a value of spending that much on the nine meter tall wall? That doesn't really teach you that much more over the small method, though in some sense that are things that you can see only at this scale.

Wojciech Węgrzyński:

Perhaps the criticism is more towards how we arm those devices, how we prepare those experiments. If you only have a limited set of thermocouples that you base everything on and you have people who put cavity barrier just next to your thermocouple so it doesn't record too much of temperature, I don't find that really helpful to move fire safety forward. If you use those rigs as experiments, as we use them in science, then you can learn much more, and perhaps that's the biggest finding of this project. You can learn so much more from those methods if you don't just do the minimum required by the test standard but you really try to understand the flammability, whatever that is, of your facade, you can do it with whatever method you choose. Perhaps that's the biggest lesson and I wish more people did it like this. I wish that those information scattered from those experiments would be shared openly with fire safety engineers so you can make your own decision based on those, not just on the fact that something has passed or failed a specific test that you never had the chance to witness or really dive deep into.

Wojciech Węgrzyński:

Anyway, that would be it for today's podcast episode. Matt has presented this on SFP conference in Edinburgh. I have a feeling that this will be shared more widely with people around in more conferences and more talks. There's a paper in the pipeline, as we've mentioned. We really hope that it will get through all the review stages fairly quickly and we will be able to share it with you. I will be sure to send the paper your way as soon as it is ready to to be read as it as it's ready to be published, and, once again, thanks for being here with me for the 200th time.

Wojciech Węgrzyński:

Whether it's your first five-star show episode or the 200th one, I'm really grateful that you choose to spend your time with me, and if you haven't listened to many of those podcast episodes, there's an entire library waiting there for you. All of them are good, all of them are relevant to modern fire safety engineering. That was the point of running this podcast to create this living library of interesting things that you can jump into. So many different topics that are in the fire science again, something that will never stop to amaze me how wide and vast the world of fire science and engineering is. I don't seem to be running out of topics to talk to and out of people to talk to, so that's that's good news for you.

Wojciech Węgrzyński:

On to the third hundredth of episodes, and uh yeah, time flies by so fast and I feel it's kind of accelerating, so I guess episode 300 will come sooner than I think. Anyway, thanks for being here with me today. Have a great day and guess what? Next Wednesday, another part of fire science coming your way in this podcast. So see you there. Cheers, bye, cheers, bye.