086 - Experiments that changed fire science pt. 4 - Runnehamar tunnel with Haukur Ingason and Anders Lönnermark

Wojciech Węgrzyński: 0:00

Hello everybody welcome through the Fire Science Show. We're here again in the series of experiments that have changed the fire science. I wonder if named Runehammar rings a bell for you. If you are someone dealing with a road tunnels or. Fire safety of tunnels in general. I guess that's the case. If not, Please, let me take you to the world of all the biggest and most important tunnel experiments done in the last 20, 30 years. Experiments that have really changed the way how we design road tunnels. It has been a very bold series of research done in a very specific state in Europe. After a series of really large fires with many fatalities these. As I've read in some of the papers. Uh, European citizens have lost the trust in the European tunneling network. And many, many advances have been done. At that point. And one of these advances has been done. by SP in Sweden now known as RISE my group of professor Haukur Ingason and, uh, an important figure in that also Dr Anders Lonnermark, mark. Both of them are my today's guests. And they take me to their times at Runehammar, explain how the research has been done. What were the challenges? What were the findings? What were their assumptions and how well they were met? Actually, it's pretty fantastic. I'm going to spoil it a little bit. They've Focused on the finding one. Answer on what is the heat release rate of a fire? In a tunnel build the whole experiment. Around that. Done. Everything to figure out that number reliably. And for multiple scenarios, figure out what's the worst outcome. And once they are achieved at they've implemented that. Or the society implemented their findings. Into standards codes. Really what they found out during this experiments. We are. Literally using an every single tunnel. That's the type of impact. I think we should be seeking in fire science, you know, making one really good experiment. That truly makes an impact. That truly changes something we can call the paradigm of the, of the fire safety design. Uh, and that's what these guys achieved, and this is why. They are here now to talk about an experiment that really changed fire science. In a world where. More publications are coming every year than ever before in the world where vague research is published for impact factors and citations. Uh, this type of research that truly makes an impact and changes from the discipline is something we should seek. And I'm super happy to talk about it with Haukur and Anders. So, yeah, that that's absolutely enough. Let's spin the intro and jump into the episodes. This podcast is produced in partnership with OFR Consultants and multi award-winning UK base, fire and risk consultancy. OFR are supporting a number of PhDs at the universities around the UK, including Edinburgh in Sheffield. And the one I would like to highlight today is the opportunity at the Fire Safety Engineering Group at the University of Greenwich. This PhD is about how can we harness the power of BIM in our engineering practice? You may recall episode 62 about BIM. It seems like a promising, useful tool. And then the development in that is much welcomed for the fire community. The PhD will use computational tools like fire models and evacuation tools. And will examine the data exchange requirements for them to be used together in one digital workflow, employing BIM, if you would like to participate in this fully funded PhD bursary. Please check the episode, show notes. You can find there more information, link to the application. Important thing is the date it's closing on 28th, February, 2023. So yeah, please check it out. And now back to the episode

Wojciech Wegrzynski: 4:31

Hello everybody. Welcome to Fire Science Show, another episode on experiments that have changed the fire science. And boy, this, this one really did. today I have with me Professor Haukur Ingason from RISE. Hello Haukur

Haukur Ingason: 4:44

to meet

Wojciech Wegrzynski: 4:44

and, uh, Dr. Andres Lonnermark from from Rice, who also participated. Hello Andes. Great to

Anders Lonnermark: 4:50

Good morning. Thank you.

Wojciech Wegrzynski: 4:51

And you guys, uh, you've set a fire 20 years ago and it seems to be still burning You have done, the famous Runehammar tunnel experiments, or you were part of the larger consortium that that has done these experiments. So I, I know that it changed the fire science because I'm dealing with tunnel fire safety and tunnel engineering. And this research just keeps popping back because it's one of the best data points we have collected as, fire engineers. engineers. I really wonder really the history of this program, what, what happened and how it happened. So let's, let's discuss why the experiments were needed, why why have went to an old tunnel in Norway to do this massive experiments, and, what were the, like the chain of events that that led to this program.

Haukur Ingason: 5:38

Yeah, I can start. And thank you for this nice introduction and uh, it's really, it was in the late nineties, early 2000 when we had all these, uh, large fires incidents and, and uh, in 96 we had the Euro tunnel and we had then Mount Blanc Tower and Saint Gothard all the, in the very sequential, period. And, and I was thinking about all these fires involved HGV so heavy good vehicles, semi trailers with ordinary, hazardous goods. And, and we, uh, knew from experience of doing fire research on warehouses with ordinary commodities. That's, of course these fires can be quite large. but at that time people were talking about 20, 30 megawatt design fires. uh, I felt, it must be higher than that. And, and, and already in 93 there was a test in, in the Eureka program, which was also done in Norway, where they measured, for the heat release rate up to 120 megawatt in ordinary, uh, semitrailer with a ordinary goods of, uh, furnitures of two tons. And, and that also somehow confirmed for me that need to do something to, show people that 20, 30 megawatt as a design fire for a truck, uh, a single burning truck was maybe too low. So, and, and these, uh, fires were, very much in discussion, of course. And, and it was not single. vehicle. It was like multiple, it was 10 15 Hmm. cvs in the world. So, uh, estimation showed me clearly that this was, uh, something here wrong here. So we were, in contact with Chris at SINTEF uh, Uh, in Trondheim since the Fire Research Lab. And he told me about a, a large scale tunnel in and, and thought, oh, that's interesting. We, maybe we should do a fire test there. And somehow that was the starting point. And, and then I went to my manager and said, Hey, I want to do a full scale test in, in Runehammar tunnel. Is, is it okay? Yeah, as long as you find some money. And we started to find money in Sweden and we got actually up to 350,000 Euros, if I recall. And, uh, and my manager said, uh, okay, go ahead, but you need to find some partners because you have not a complete budget for this. I think you need at half a million. So So I was at that part in, involved in project, project called Upton. and I, I asked the management, can we use our part in the, uh, UPTUN project to, to somehow these tests? And, and there he said, yes, of course. That's interesting. And you should also add some partners here also. And, uh, we felt okay, TNO in Netherland, that's excellent partner. And, and also SINTEF in Norway were partners, so they were also part of Upton. So, so that's how we linked into the Upton project and were able to actually perform this in 2003.

Wojciech Wegrzynski: 8:47

Hmm.

Haukur Ingason: 8:48

that time there was a young researcher called Andes Lonnermark he was, uh, I felt I could not do this alone, and we needed help. And that's how, uh, Anders became involved and, and really, did a major impact on, on the performance of this test.

Wojciech Wegrzynski: 9:06

how did, uh, the tunnel. Fire safety field feel after all this because it, it was like an age of really huge fires in tunnels, like one after another, like Gothard Channel uh, Mount Blanc. There was kings Cross, uh, fire, not, uh, not the road tunnel, but also involving, uh, underground Infrastructure. in, in the book after the, the proceedings of the symposium. After the, the experiments, there's a uh, that says that, that people lost faith in transport network. Did you also feel this political, necessity to perform this test, or was it just purely engineering driven, we need a new design fire.

Haukur Ingason: 9:47

I, I can respond to that because I, I recall I was purely driven by the, the knowledge of, I knew there was something wrong in the numbers, uh, and also the science, because we had been doing a lot of model scale testing and we could see this really clearly. And that was really the, the background to do this. Uh, we wanted to some kind of valid validation in full scale test. So it was more science driven, curious, driven than any political, uh, question what, uh, at least concerning

Wojciech Wegrzynski: 10:19

Fantastic. And, uh, you've entered the research, was the question of heat release rate, the main, uh, research cap that you had or were there like immediately things, okay, we also need this and this and this, or, or you were just focused on the size of the fire?

Anders Lonnermark: 10:37

yes. the heater side was, was the main driving force that, that, uh, in most standards they say, uh, this 20 to 30 megawatts is the maximum. and Ker very confirmed, believed that, that, this was much higher. was much uh, this was of course the starting point from my participation of this research. but we also looked at other things, uh, like, uh, the high temperatures and, risk for fire spread, and, uh, also the possibilities for, the fire fighters to fight such large such large But all came back to like to uh, gap between, uh, the thought of the maximum hit rate and what we thought was the, the actual case. And then of course, a scientific part of this was on how to measure this in a, in a correct way in a tunnel with such a large, uh, fire large and, uh, all the practical things about just the measuring the heat, measuring rates. And, challenge was also of course, that we wanted to have have levels of the heat we had looked different transport companies here in, in Sweden and what kind of, uh, mixtures of materials, we can see there, and, uh, was special then mixtures of, uh, celulosic material and plastics, material uh, that we find out that now that approximately 20%. 20% was quite common. quite common. then we tried to, arrange, forecast with different types of those, those that's the same percentage, but different type of, of mixtures and mixtures So reached, uh, different levels of maximum levels of heat release a lot based on how the, these were, sort of ordered, and, uh, set the set how the setup looked like. Then of course, very big driving force was that we thought, okay, we are convinced that, that this is the case. The maximum is much higher than what the standard said, but we have to show it. Uh, we really have to show it with an experiments. Modeling will not be enough here. We need to show this in a real experiment.

Wojciech Wegrzynski: 12:39

I, I hear that very often in the fire science that something is obvious, but, uh, please give me a citation for that. And it doesn't exist. There is, uh, there's many obvious statements that, that, uh, require, experimental proof, because sometimes when you go into, arguments with arguments with or, or some, you know, deciding parties, parties, for them, uh, your say as a scientist is, is insufficient. They want, uh, hardcore proof. And new really solid proof was, uh, obtained. date. I've, uh, read that, uh, the compositions of your fuels, were, were, were four tests done. Uh, three of them had some sort of wood pettes in different numbers. So the first one was mainly wood, pettes, and some, plastic materials. The second was, uh, half, pallets, half mattresses The third was like grill. Furniture, I guess it was Swedish Furniture

Anders Lonnermark: 13:30

Yes,

Wojciech Wegrzynski: 13:31

that's correct. that's, that's my, that's my guess. and uh, the fourth one was, uh, mainly, mainly. plastic cups. So, so that's, that's a very interesting, interesting choice of materials. You said that it, it was driven by the urge to have different heat release rates. But, uh, I wonder you were venturing literally into unknown. So how were you designing this, fuel sources this experiments and, and how, how did you even choose the, the number of four.

Anders Lonnermark: 13:59

Well, as I said, we want to have different levels, but we also wanted them to burn, uh, a bit differently. uh, and uh, our main thought was that, okay, wooden, wooden pallets is we have the knowledge of wooden pallets. They're, pallets they an actual case that you see that in transportation, even if these were, were piles of, pi pallets. but we also thought we need to have. also needed plastics and what is better than to, to arrange plastic pallets that have the same sizes. And we just mixed in, mix them in, in the correct, ratio. So that was the starting point. Uh, and then we wanted something to burn a little bit differently, and we also saw that okay, mattresses, it, it's a different type of, of different with this being soft and it has also a different it chemical composition. chemical so the reason to have these pieces of mattresses with and the same size of the, Wooden pallets, uh, then was case of stability in that case, that, they're not as solid. not as therefore we had to arrange some practical things around this setup that we use for all the tests with some nets that it does didn't down. But, but the main thing that was to have these, uh, different types of material, uh, types of that we thought was quite common and useful for us. for the plastic cups is actually actually standardized goods that we use for other testing. we use So we had knowledge of how they burn, of uh, what kind of, uh, Smoke it produces, uh, about the heat rate and all things. So that was also then also. a guess that, that, that would be very suitable. then we came up with a, we would be very nice to have something that was real commodities real uh, therefore we had this test with furniture and we tried them to have, as good this good as possible with the similarities to others. But of course, this was different. In some cases, there was very solid There was very with, with, pieces of, furniture and while others were more, s and Hmm. open, so to say, in their structure. So, but, uh, it turned out very well, I think.

Wojciech Wegrzynski: 16:00

Because of your famous pictures, uh, of, of this pettes, uh, burning in, in this massive configuration. Now, whenever I see a, a truck with Pettes on the road, I'm, I'm immediately urged to take a picture of it. And, uh, when switched somewhere, I've seen three in my life, uh, already on Pia roads, It's like a unicorn. And I guess the drivers are always confused why someone is taking a picture of this, this seemingly uninteresting truck. topic. Haukur you've mentioned, uh, your experience with ordinary hazards and, as, ordinary as you were saying that, uh, it, it clicked in my, in my mind, I, mind, I, remember your papers from like 95 where you were doing like, first, uh, numerical simulations of natural ventilators. So it, it's fascinating how person jumps from home, one field to another, to, to completely change that another field with the experience from the previous one. Um, wondered at that time, 2003 or even before when you were planning, you've put, the big source of fire that this, this plaz, this, all the materials that Andres was, talking, talking, but, you, had to, Have an, and some sort of idea how the fire will develop and it was a forced flow experiment. was at that point, any expertise in how this forced flow will change the fire the Like what were you expecting, uh, from this fires and wires and it go like, uh, in a different way than, than than expected?

Haukur Ingason: 17:27

Yeah, uh, recall when you are saying it, of course, these new numerical simulation of fire course, the, that, that's a part of my, but PhD is on the rock storage phase, Hmm. a vertical piled commodities. Hmm. and by accident really, I came into the tunnel world and I, and I, I just saw the commodities on, on the trailers. That was just a, a horizontal commodity, in a blowing situation. You know, it is like verticals. Fire spread is governed by the, the aided flow of, of flames and so on. But in tunnels, when you have forced ventilation, you create a situation. You know, the flames follow the, the commodity like in a, in a, where it's fire. So there's a similarities there. But, uh, anyway, that experience, of course, I took with me and I, I knew what parameters were governing the fire spread and, and the rate of heat release rate. But, uh, I had also been doing a lot of model skill testing, both in, in warehouse phase and. Took that into the tunnel world and, actually, uh, these tests in, in tests are really based on model scale tests in the design that we, we did, test in 2002 in model scale to evaluate what and how large fires, what situation they create in Hmm. the, the, back layering critical velocity, radiation temperatures, smoke spread and so on, and all that. We took that with us to the Runehammar experience, how to measure the heat related rates, what techniques should we use and so on. We, we had experienced that from model scale test, and then we had of course, what's really made the case for us in, in the Runehammar and, and Anders was highly involved with planning the intermediate size, file, laboratory test where we piled up when we had decided after the survey, that's the type of goods we will use. We piled it up and took one row of the, commodity in the track. It was like 10 rows of, uh, piles. And, we put that under our hood, uh, fire, large fire collector, and measured. the heat

Haukur Ingasson: 19:39

release

Haukur Ingason: 19:39

rate. And from that we were able to predict what should be the, uh, heat releasr list rates. And, and that was really a very accurate prediction. And, and that is presented in the conference after the fire tests in, in 2003, that prediction. And, and, uh, and this was, uh, Part of that and, and what was really, amazing how well we predicted it in advance, the heat release rates, because o of this experience with model scale test, intermediate size test, and then finally the, the full scale test. I think this is a very important parameter that you prepare large scale test in such a way.

Wojciech Wegrzynski: 20:19

I guess, uh, the budget was very large, so you really want to get to the most bank of your Euro you can. Uh, if you, if you can burn it one just a few times, you don't want to, go unprepared. from your memory what, what was the number one, like technical challenge related to the program? Like what, made you sleep the least least

Haukur Ingason: 20:41

Yeah, I mean, we had a lot of, uh, discussion with different people and, but number one, I would say the protection of the production? a, a, abandoned uh, tunnel with no protection at all. It was just a rock tunnel.

Wojciech Wegrzynski: 20:56

Hmm.

Haukur Ingason: 20:56

And, uh, thankfully through the, uh, Upton Project, we were able to get in contact with, Promat International, another Netherland company, uh, called Gerco who, who helped us to fit the, Proma boards into the, Tunnel because Hmm. boards are not usually used in this type of tunnel. But we found a solution they sponsored this really. So Oh were luckily to, to get that, uh, help and, and, for, uh, the test was really, the only possibility to do because we would never, uh, be able to do that. And we were actually in, in contact with the Norwegian Road Administration who us the tunnel in, in sense, they didn't require any. payment for being there. They, they gave us the opportunity to do this and, and all the environmental, uh, parts of it was, uh, dealt with with them. So we are very thankful for, for that as well. But the, the most challenging was the protection, also measuring the heater list rate, uh, where we, and we had to, there was no fans in, in the tunnel, so we had to get a mobile fans. Uh huh. we got a German company called BIG we had two large industrial, mobile fans for industrial, uh, buildings, and they worked perfectly. They could give us over three meters per seconds in the tunnel. So we were thankful for that. You, sorry, there was nothing there. I mean, it a pure, pure, and, uh, Andes can tell you more about that, uh, because, uh, they really, it was, was a hard

Wojciech Wegrzynski: 22:34

so you were not allowed to collapse the tunnel.

Haukur Ingason: 22:36

We were not allowed to collapse the tunnel, and we made agreement with the Norwegian Okay. that, uh, we should pay for all, uh, repairs. But thanks to this protection, we were somehow, uh, able to, to solve all that. But there, there were of course, uh, parts which fall down because we didn't, we only protected like 75 meters.

Wojciech Wegrzynski: 22:58

that, that's a stressful environment. Anders you want to add something that, maybe, maybe tell me the secret, how you've measured the hit release rate

Anders Lonnermark: 23:05

Yes, if we start with that, about the heat risk rate, which was the main challenge, and what we have learned a lot of we from, uh, also after that, uh, is that we measured from the consumption of, uh, oxygen in the same way as we do in, way. fire telemetry. elementary. made the entire tunnel into Cal large kilometer. but we wanted also the, the, smoke, uh, fire, gases to be well mixed, so that therefore we put this, uh, what called measurement station, like, very close to the, one of the exits, uh, 450 meters of the fire. And there we had a large station of temperature measurements, uh, oxygen and co common monoxide, corona dioxide, measurements and, yeah, measure in, in a similar way as we do in in fire laboratory, but used, as I said, the tunnel tube as a large, calorimeter

Wojciech Wegrzynski: 24:00

so, so far away from the, from the fire, you were measuring the velocity, oxygen concentration, and from that you were, by oxygen depletion, you were, um, estimating the, the, the heat release rate, the oxygen consumption. Perfect. So it's, it's convenient. The tunnels are tunnels one directional, uh, pipes, and, uh, if it's in the rock, it's quite, uh, tight that definitely helps. And, uh, how did you handle the upstream? Because, uh, you probably have not known that. Uh, well, like you mentioned that you did scale research, but you could have expected some back layering maybe, or you were perfectly sure that there will be no backlayering there will be only one directional movement of because that would kind of make the diff measurements quite difficult to, to, to get, if, if you had some smoke going front upstream.

Anders Lonnermark: 24:49

Now our, our aim was to, to not have, uh, ba have, of course, we studied, the part for the, as I said, with fine rescue services and their, and then possibilities to extinguish fire was one part of the research. So we, we had temperature measurements temperature measurements to see if we had, uh, any backlayering but we, our aim was to have aim in the, the order of three meters per second, ventilation in the tunnel. Uh, and we had to had help, uh, to get two large get fans, um, one at the entrance and one inside the tunnel. Two, two, uh, ranges. But what we learned was that, uh, the setup itself and itself fire when it got so big, was a big resistance. Uh, so I, I, in reality, we ended up with ended bit more than two meters per second. two meters And, uh, therefore we also had, quite significant, back layering, during these tests, especially the first one, which was the last largest one.

Wojciech Wegrzynski: 25:48

The largest, eh,

Haukur Ingason: 25:49

I, I think, it was a little bit a surprise. Uh, what I recall that, uh, we had this huge resistance, both us and this mentioned the, the fire, but also we had, beyond the, the fire, there was a downhill, uh, I think the, the slope was somewhere between one to 3% or something like that. And, Downhill, created a buoyancy resistance to the, to the, the fans. So the fans suddenly started to sound a little bit different, we noticed our, our velocity measurement are going down. And on the, then suddenly in the middle of everything, there was, uh, you know, the, the re at 130 megawatt or something, we started to see some kind of pulsations. That was a surprise. We didn't know that. And, uh, I mean, there was a lot of thing happening there. And I, I recall once, uh, I think it was in the first test, I went into the portal on the upstream side because we had no smoke there. And I, I wanted to see, can I see something? Because nobody was Hmm. tunnel. Of Yeah. cameras and, and all the measurements. Nobody was in there. And I, I didn't see so much, uh, of the fire. But when I was coming out of it, there, there's a filming sequence of me coming out and I see so very, I, I'm like grabbing my head with my hands. And, and I, I, I'm totally devastated because I started to feel these pulsations, you know what, what's this? I felt, are we losing the control of the fires? Uh, what's happening? And, uh, I recall this so well, and, and, they, they really, there were, were definitely some surprises.

Wojciech Wegrzynski: 27:28

tell, tell me more about these pulsations. I, I've seen something like that when we were doing hot smoke tests in the Waro Metro. and it was kind of, kind of hilarious and kind of stressful because, uh, we were commissioning a new metro line that was crossing with, existing, uh, metro line that was in operation. And there was like literally one tunnel that was joining them together. And we were doing hots smoke test in that tunnel. And we've seen this, this like pulsation ation Like every few seconds the smoke would move back five meters, front seven meters. meters. was moving towards the existing operating metro station. So we were really stressed if it'll enter, I, I guess, um, it's a hydraulically it would be similar experience to yours, but yours is probably of different physical origin. So, uh, was this pulsating movement?

Anders Lonnermark: 28:15

Maybe I can answer that, because that was quite large part of my PhD studies when we realized that it was not just ordinary fire positions that you can see from, uh, liquid fires fires cause of under ventilation. We also can see, uh, the fire breathing air, to which were sort of a starting point. But then we realized that, that, whole tube acted like some resonance, uh, cylinder, in the same way as, as, uh, an organ pipe, for example, that you study in physics. in and, uh, I started to look more. In detail into this and, uh, and, that this has been studied before and was called something like, uh, thermoacoustic instabilities. and even earlier they talked about something called a singing flame, singing where you had to get a sound from, from, uh, a pipe where you had a heating source. you had what it is, is that you you have the combination of a heating source of some kind that can give energy to a flow. So you need to have a flow. and then it's also related to where you put, this, energy source energy sort of giving energy to, to, the node at that point. Or if you, there is someone working against that acoustic node in, in a certain point. So it's very so it's very relevant also where you place this fire. And when we started to, to know this, we could also. Calculate and see that the frequencies of these pulsations was very accurate in accordance to some of these node. And they notes interacted to give some combined notes as well. So that was, uh, very fascinating. very we don't know how, how dunno important this is for, for safety, for but I think, uh, it's very interesting for explanation scientifically because we have seen it, as you said, also also in other cases other cases ations where we can also have related also the, the fire to having tubes that was shorter, which gave us another type of frequency. So it's very interesting.

Wojciech Wegrzynski: 30:14

Anders, if I'm not wrong, you are some sort of mu musician, right? Or you have

Anders Lonnermark: 30:20

I sing, uh, like to Yes.

Haukur Ingason: 30:23

a famous for singing in ISS conferences.

Wojciech Wegrzynski: 30:27

it must have been a musician that went into the tunnel to discover, um, thermo acoustic phenomena. And, uh, and the scientists who mass, uh, commodity tests to see commodity on wheels, wheels, to, to plan a commodity experiment. Inza what, uh, fire science is a world of, um, of, lucky accidents that, puts the perfect people in the perfect place in the perfect time. I'm very glad this, uh, all of this came so how, how long did it take? Like how, how long did it take you to prep the research? How long did it take you to do the burns, the take process, the data? Was it a very long program?

Anders Lonnermark: 31:06

It was a long program and, uh, of course Haukur started course early in the planning and having the ideas of what to do. And he mentioned also this, uh, we did in our laboratory. then a lot of the work was practical. was cause this was urban Tunnel with literally nothing in it to, to assist us for performing fire tests. So we had Tori Range pide electricity, lighting, the somewhere to clean up. we used, uh, like a waterfall for cleaning up. cleaning up, but we have arranged toilets and some work shed to be somewhere between the tests. Uh, the the protection protection a lot of time, as Haukur said, but then we also had to arrange machines to, to have something to to, own tractors, move all the, these commodities that we were using for the tests for the build up there was a new setup for each test, uh, with steel frames, uh, see, uh, a floor for, for this, uh, palace to be on. Of course all the measurements all to be arranged. So a lot of fact planning and the renting things, uh, was done before. But then in the tunnel itself, after the protection had been been of started, sort were there for, we uh, like two months uh, like in, in, in Theam test, starting with, sort of digging grapes for, for, for the, or channels for, for, for the cables to be protected. the Geico, making the frames for from a board to, from a tech board to be. Mounted. So they were doing their job and in the same time and we were preparing the measurements and all the cable drawings with these long distances. And also keeping track of course, of what cables go, goes to, what measurements and all that. All that is more difficult when it's so long distances long. and one, one very 1, things. There was no lighting in, in the tunnel, so the uh, we had to arrange also lighting where we were at, at this site where the testing site, but there were no other lighting in the tunnel, so we had to have like lamps. head and we had to arrange and where we range cause of the distances, uh, between our work shed and the fireside. the fire so we had to have these so headlines given some kind of light where we worked, light but it was. but was Interesting phenomena when we came from the very, very light outside and take the bicycle inside the very dark tunnel even you have the highlight. It was headlight moment before the eyes adjusted. It was completely darkness then. And then we had these sort of small lights to see that it was, uh, safe. So with all of those practical, funny things, but also sometimes very very. thing, practical things to really arrange to make it work.

Wojciech Wegrzynski: 33:51

and, and how long it took between the experiments? Uh, you said two months, but two months was for all

Anders Lonnermark: 33:56

Yeah. So it's app approximately one month for just arranging things, and then it was a month for the test and approximately one week between each test.

Wojciech Wegrzynski: 34:08

that, that's very, very quick. And, and how many people were involved or around

Anders Lonnermark: 34:12

Uh, in total, uh, think, maybe around 20. around billing up, the protection, projection, the practical arrangement with measurement. And, measurement. also hurricane mentioned that we have three different different scientific doing different types of measurements. And, uh, we all had, uh, a number of, of people at the site,

Wojciech Wegrzynski: 34:32

I'm cheating because I have the conference proceedings in front of me, and I, I found, found the SP hoot test results, uh, that you've mentioned, Haukur and I see that the predicted, heat release rate, uh, for pallets was 186. And in your experiment it was like 200 something. I, let me check Yeah, I you remember that. Good. for mattresses, the predicted was 167, and that's very remarkably close to. outcome. and the cops also, you predicted 79, and it was also in this range. range, I'm fascinated because it's, uh, the, the laboratory tests are in free burn, situation. yeah, in the uh, not only had a tunnel, but you had this protective, uh, enclosure. It was very close to the fire. So I would assume the effects of like heat, radiation and everything around a surrounding that would be, um, massively changing that, that size of the fire compared to a free burn. But, but it seems you, you did a very good estimation by just multiplying it. How would you explain that? Just the oxygen diffusion in the

Haukur Ingason: 35:42

I explain it with luck comes with skills.

Wojciech Wegrzynski: 35:45

I mean,

Haukur Ingason: 35:46

it was, it was, uh, really, I, I, always remember we felt this need to do this in, in our file laboratory. And, I knew from experience, uh, in adding up some up, you Knowing, uh, the, the rate of, uh, you know, spread, you can't, uh, get this very close. And, and that was really, we, we were quite convinced that we would get this, uh, high heat release rate, but at the same time we, we, I think we were more surprised about the temperatures we Okay. expected, uh, 1,350 degrees. Uh, the RWS Curve, we more were in the range of 1200 degrees and, uh, hydrocarbon fires like that because we had seen this in our model scale test and in in fire test that we have usually thousand to 1200 degrees, but. in, in retrospective. We know, uh, that after doing calculation modeling and so on, that this was really not surprising. You know, the, the thing is that we had a very good, fire protection of ports who also happens to be quite insulating, and that affects the, Hmm of course. also we had a, the ventilation of course create this situation, which we didn't have in our fire lab, but we know the spread between the piles is really by the, exposed, way of wind into the fire lot. But, uh, we had, in our test, we had a tarpole as a protection initially, but that burned away quite So we had like a, a stream into the goods. So, so we, we were quite convinced that, uh, how it will spread. But, uh, Temperature. Definitely were a surprise here.

Wojciech Wegrzynski: 37:37

I'm asking, uh, this, for, for a reason. I, I'm wondering to extent someone can extrapolate these fire dynamics into modern tunnels. The tunnels that I'm designing today, you know, they have three lanes. They have, emergency lane, they have two meters of, of pedestrian walkways on the size. They are six meter tall. They end up having like 120 square meter cross section even. here, you had a tunnel with a cross section of 30 something. Uh, when, uh, you've built the protective and closure, do, do you think the size of the fire could grow to the same scale in, uh, much larger tunnel where the, all these feedbacks would be lesser?

Haukur Ingason: 38:17

with the same ventilation condition and the same around the commodity. Like it was really a direct blow at the, the, since the tarp in the plastics, it, it disappeared soon. We have done test later in with steel plate in front of the, the goods. And, and that slowed definitely down the fire growth rate, but the maximum heat lice rate because it, it's dominated by the surface area of, uh, how large areas involved. And we know that the heat lice rate per unit, area is quite in most cases, even if it's blowing at that, uh, so, so. the fire growth rate definitely is influenced by the range of in, in that, uh, high ventilated situation. If you, if you lower the, the ventilation rate, of course you'll get slower heli rate, but I think it will, it'll more controlled by the, the type of, uh, how you arrange the commodity. And usually in trucks you have a cabin in front or you have some kind of doors at the backside. All these things affect, so these run tests really. Showed some kind of, uh, what you can expect. Uh, in the worst case, it was like, uh, you know, as you said, uh, it was only 30 square meter in, the fireplace. We had this, uh, protection. Uh, we have done tests later without this type of protection, but with, uh, with spray concrete and, and we don't get that high as we got in, in the room number huh. in 2003. So, so definitely there are parameters affecting Hmm

Wojciech Wegrzynski: 39:58

So, so this is pretty much the, I, I like how you positioned it. This is, this seems like a worst case scenario. and that, that was what, what you was suing because, uh, in tunnels I guess we should be prepared for, pretty bad scenarios. also, uh, So, uh, more question to the heat straits. You've also mentioned that the growth was linear and that, that was quite interesting to me. I'm, I'm, I'm living in the world where the fires grow in a quadratic, manner. So was that something that surprised you that it was linear or, or

Haukur Ingason: 40:29

in the reality, not because we had seen that in, in our uhhuh. was also so it, it's more related to the, the, how the goods is, piled

Wojciech Wegrzynski: 40:38

so again, it's a, it is a fuel, property more than, uh, the, the tunnel setting property. Okay.

Haukur Ingason: 40:44

I I would say it's more of the type of fuel you are using. Hmm. of course, wind, uh, affects this. It's a wind fire spread

Wojciech Wegrzynski: 40:52

and back to temperatures. So you've mentioned, you, you've seen this, uh, massive, uh, 13 hundreds, range, uh, temperatures that actually match the, the curves everyone in the fire testing industry hates because it's, it's challenging if we, we have accomplished, uh, self melting of one of the furnaces. When we were a, a attempting one of these, uh, tests for these massive temperatures, was it only in the biggest fire or, or it was consistently in this, in this range, uh, in the smaller fires to.

Anders Lonnermark: 41:22

it was the highest temperature was, was in, in the first test, and that's where we also realized that these high temperature were actually possible. So it's, it's was relating to. the type of, test that was, uh, performed, but we reached high temperatures, in, uh, most the test. But, but test number one was the extreme case. Uh,

Wojciech Wegrzynski: 41:44

Why did you choose to make the biggest fire? The first, like if you, if it collapses, you have the best results anyway, or that's like risky

Haukur Ingason: 41:53

I, I, Yeah. uh, we had a plan, and, we actually, were wanted to do a little small test in the beginning and then, you know, have, uh, some kind of, uh, final test with the, the, the LAR one. We, we knew that this was the, toughest one, in discussion with, uh, the partners, we came to this conclusion that we should, when we have the best protection, we should do the, the largest Hmm. So it was, uh, more re practical reason and in retrospect, it was a totally correct decision because was a huge, uh, stress to the, the protection system, but they managed to, to keep it, uh, intact.

Wojciech Wegrzynski: 42:37

in

Haukur Ingason: 42:38

that was a

Wojciech Wegrzynski: 42:40

ch challenging, very brave decision. let's move to the impact of the program. I assume you've achieved your goals. You found your hit release numbers. So how, how happy were you with the outcomes of this, of this research and, and do you feel it accomplished what was set in front of it?

Anders Lonnermark: 42:57

we were very happy. Of course it was, sort of overwhelming overwhelming during the, the test series, relating both how to handle these big fires, but also the, the results that were high both in temperatures and heat risk rates. And also that we have sort of reached what we thought and of course realized that, that this is, very important for tunnel, fire, science, and, uh, society. and that's of course also why, we. Had this, conference and also the result of the conference and the, the interest from, from many organizations. and then of course, then to use this R and that hook can tell more about being, uh, part of different standardization conversation, and, and, these numbers were discussed afterwards. How, how, uh, should I relate to different types of, uh, scenarios or situations, and all that and all myself, of course, being in the middle of a PhD started, it's, that was, important thing that, and this, thing I was very lucky to partner up with Haukur in this and getting five. Papers outta these only four four that was, uh, very good and very interesting and very, very focused work so to thing.

Wojciech Wegrzynski: 44:10

what a PhD topic to have, uh, Haukur can you tell me more about how, how the data was, uh, disseminated in the standardization committees and what impact on the, the industry it, it made.

Haukur Ingason: 44:24

somehow, of course, people had started to realize, uh, 2030 megawatt is quite low in relation to what we see in, in, in incidents, involving ordinary, hazardous goods. became a part of the N F P A 5 0 2 committee in 2009. Uh, when I came into, the committee, the R w S curve was already there. So, so I, I assume it was somehow related to our test that, uh, made it, uh, possible to, to somehow, that type of, uh, information. the, uh, 200 megawatt fire that came, during my, Process in the, in the N F P A committee, I think, uh, it was in, or it maybe was already there, but that definitely, uh, it was 20 to 30 earlier, but today we talk about a hundred megawatts, uh, for, for trucks and even, uh, and two, 300 for, for, petro tanks and so it raised the level of, uh, the design fires. But, uh, it's also started, in combination with the incidents, to use fixed fire fighting system. And I, I think these tests really somehow proved something. but the incident also proved something. The, uh, the eureka test in 2 19 93 also had showed us the way, so we needed to do something and on in within the pr. There is of course also these numbers. Uh, you can see people are not willing to go up to 200 megawatt, but a hundred megawatts some kind of consensus. Uh, in the room, Imma test. We only tested. To 11 tons, uh, and, and trucks, trailers, uh, they, they can't carry much higher loads than that. So, and this is only one vehicle we, we were interested in, in the fire spread also. And, and we really succeeded to show that, vehicles about 90 meters away downstream, they could, uh, start to burn Even. We had a target only 15 meters because we, we, we thought in the beginning, this is only four vehicles close to each other, but we really were able to show that these phase, they can't jump like, uh, 50 - 100 meters easily. Hmm. that's something what this has shown. But in a standard standardization organization, I would say, this? Uh, a number here is a hundred megawatt, and that that's was raised from 20 to 30. And, and just by that, I think we succeeded to, to have impact and also the impact on the, on the fixed firefighting,

Wojciech Wegrzynski: 47:03

Yeah.

Haukur Ingason: 47:04

questions.

Wojciech Wegrzynski: 47:05

that, that's, that was my follow up question because in the conference paper there are, papers by Alan Brisson on, on the sprinklers. There are some early about of, uh, water aist in, in, in tunnel settings. I guess once you had the you that the virus can be this massive, that the temperatures can be this high, this also like opened the, the way for active fire protection to show how successful it can be I guess, many research further followed. Uh, I know about the research in, in Spain, done with, with different suppression systems. Can you just

Haukur Ingason: 47:41

Yeah. I know. I was involved in, in, uh, it was 2007, in a series with, uh, water mis, uh, testing and, and, and the, and the driving industry was really the water mis manufacturer, not, not the ordinary sprinkler, manufacturer. They have come into this later, but, uh, the, the waterest industry was really, uh, more unrealized, the need for, for cooling down because the waterest is very effective in cooling, uh, down the temperatures. And they saw it very early. The, the possibilities here and, I think partly due to the UNAMA test pit, of course, partly due to what I saw in reality. I mean, these huge fires, we can't have it like that. but somehow you need confirmation Runehammar has played a role in that. It was confirming something. People maybe have thought or knew.

Wojciech Wegrzynski: 48:33

If someone gave you today opportunity to repeat that, uh, would you do it and, and what would be your number one research question today? If you had a chance? If I give you half million Euros in a tunnel and, and, and, uh, support from,

Haukur Ingason: 48:49

Yeah, that is a good question. I, I mean, uh, there, there are of course always need for more full scale tests and, we somehow these tests in, in 2003 somehow proved for us and, and others that, ordinary hazard this material can, uh, make a, singing fires in run hammerer and, and That's, that's quite interesting. But, uh, anyway, uh, I always said that I, my dream is to, uh, run a petrol tank fire in a tunnel. I mean, we saw in the Norway 2015 that actually occurred. Such fire doing that type of fire in, in a tunnel is of course maybe getting too late because we have electrical vehicles and things like that. But I, I think somehow doing, uh, heavy, good vehicles with all near or with like batteries or what, I mean

Wojciech Wegrzynski: 49:39

With

Haukur Ingason: 49:40

And. That, that I think there is a time to do something there. the future will show what what is the most interesting thing. Of course, we have a lot of debate on, still on, critical velocity and back layering, things like that. Uh, but most of the research today is done in, uh, model scale test. So somehow we need to calibrate again, uh, the, all these model scale, you know, research, which has been done to, more full scale testing. So, so I see maybe we don't have to look for the biggest fires, but maybe we have to look for well defined fires and, and we have to go into the new al alternative fuel, research, uh, you know, frame for the future. So,

Wojciech Wegrzynski: 50:24

Thank you very much. I, I must say, I, I, hate the modern science with this, uh, tiny model skill, uh, tunnels, figuring out, you know, critical velocity to the third significant digit and, uh, innovation coming from this time. We've put, the fire sources not next to each other, but to each one behind another. And there's a paper and another paper when they're like separated by three lengths and five. It is. it seems more an industry oriented on publishing papers than on tunnel fire safety. Unfortunately, that, that's, that's my view on the modern fire research. This is why, uh, why Research projects like like or we were discussing today feel like, you know, some, someone opens window in a room and, and le lets all the fresh air in. Th this is the type of research that that fire science needs to truly advance. Not, uh, just, uh, you know, have impact factors and citations. Uh, that's, uh, that's what I really appreciate from your program.

Haukur Ingason: 51:22

I think, uh, concerning the how to proceed on, on, on, I, I review a lot of, uh, these journal papers and I know exactly what you're talking about. but we have a lot of experience of model scaling, but, uh, we need to do this with full Yeah,

Wojciech Wegrzynski: 51:39

Exactly. Exactly.

Haukur Ingason: 51:40

I always say you learn by model scaling, but you have to confirm by full scaling. but, uh, know, we have this, uh, conferences which originate from the, uh, test in Runehammar we had this conference as, and as mentioned 2003, and then we started, uh, this is tss, international Symposium, tunnel Safety and. We have, I think a 10, in, in April. Uh, we will have in Stavanger uh, the 10th I S T S S, and that's also a product of these, uh, fire tests So, so it has given both us and hopefully research community is something, and, and hopefully IST is a conference where we try to focus on science also and also on practical situations.

Wojciech Wegrzynski: 52:31

and then this year it's very conveniently, organized together with fires in vehicles. Uh, five conference. They're like one next to each other, uh, in the same place, I think. So you can like with one triple 10, both if I'm not wrong. So, so that's a very interesting opportunity to visit s Stavenger and, to learn about autonomous vehicles and, uh, all these aspects of safety Anders uh, final question to you. How, how did the, this program change you as a young scientist and what, what was the number one lesson for you as as a young PhD student given such a toy

Anders Lonnermark: 53:01

Well, if I answer that question in two ways, it of course changed my scientific life, uh, completely. Uh, this, were a different type. I mean, I've done research before, done but, uh, both. seeing the influence that these results had, uh, was very satisfying. But also the the, the results we, we saw also gave other opportunities for Haukur and me to continue to the research within internal research within the uh, a platform here that HKU has been responsible for, very much increasing the, the research within tunnel and underground facilities and of course IST ss and getting to know so many other people's many in the fire safety society. So, so that was, And big change in my certificate career. Of course, not only getting the PhD degrees from it, so that, so that is one side. The other lessons learned is of course, these large scale tests take a lot effort, uh, costs, uh, a lot of planning. There are many things that that can go, go wrong, uh, or at least needs to be changed. But with, uh, a lot of planning and, uh, use of previous experience, you can perform these tests, uh, in in a good way that they are very useful. very And, to sum up that sometimes we really need these, as also Haukur mentioned, these large scale tests because they give much, so much extra than then extra than. or, or model scale can, can do for one thing to convince, one a other people, but also to, to be used for, for modeling, validation later. And we actually see what, what, what it is when we put on fire, real large scale test.

Wojciech Wegrzynski: 54:43

Fantastic. Gentlemen, thank you very much for coming to the it was fantastic to learn firsthand, uh, from you about Reno Hammerer tests. And, uh, I mean, if, if you're not bored with it, I wish you wish continue talking about this important important for the next, uh, decade or so, at least, uh, because it's still, uh, making making impact on, on the fire science.

Haukur Ingasson: 55:05

Finally, we would like to, thank our fantastic colleagues, especially our technicians who made a, a great job during this test. And, uh, also, To our manager, Ruth Fixer and Morgan mc, who have played a major role in, in making this possible. And, uh, also of course, we want to thanks to our Swedish Financeers as well as our partners and UPTUN project to make this possible. And at the end, I would say the. Work from, uh, the, uh, proma International and, uh, GERCO as well as, uh, the fire ventilator big in Germany was, uh, was necessary to make this possible.

Wojciech Wegrzynski: 55:49

thanks again and see

Haukur Ingason: 55:51

Thank

Anders Lonnermark: 55:53

you. Thank you.

Wojciech Węgrzyński: 55:54

And that's it. I hope you've enjoyed this episode. Runnehamar.. This experiments have really changed the tunnel fire science and they steal make an impact today. I recall a thing a year ago. We were publishing a paper with a student from Spain, Diego, and we were investigating one D 3d, coupled modeling, and we used Runehammar case study for, for that, because it's so well described. So well measured. that is really well available. So why, why not using that as probably the best experiment we have. So even though it happened 20 years ago, Steel today. It is a very, very useful piece of research. And it was huge fun to interview the creators of that. Uh, I mean, You can learn all about the science behind these experiments from the papers. But, understand how they felt, what made them do it? What were the challenges were where they had to push a little more. All of this fun things. Is what I try to deliver through this episodes of fire science show. So I really hope you've enjoyed that. I know that. experiments that have changed. Fire science are one of the most liked parts of the fire science show. So I'm going to produce more of them. If you have a good idea about an experiment that has changed the fire science. Please send it towards me and I'll try to organize. The discussion with creators or people knowledgeable. About that, uh, background of that experiment. So thank you for listening and see you again next wednesday thank you bye