090 - Objective driven suppression system for Swedish tunnels with Ulf Lundström

[00:00:00] Wojciech Węgrzyński: Hello everybody. And welcome to session 90 of The Fire Science Show. Today, I'm going to venture into the world of sprinklers or actually my today. Guests test. Done a lot of effort to not call them sprinklers. So let's say today we're venturing into world of water, fixed firefighting systems. And the in two tunnels and the guest is Ulf Lundstrom from Swedish Road Administration. You may wonder why I'm having a Swedish road administrator in the podcast, but that's a, that's a very good reason.

[00:00:26] Wojciech Węgrzyński: As the road administration is, is a client is a company that is building roads and tunnels in Sweden. And for some reasons that are mentioned in the podcast stay figured out, okay, we need some fixed firefighting systems in their tunnels, But they did not really like the state of the sprinkler market at the time.

[00:00:43] Wojciech Węgrzyński: And decided that instead of purchasing the solution that exists and for, or following a code that exists already, they will just base on their needs and base on their capabilities. Like what water is available. Uh, how they can install them. And so on, based on those, they will just [00:01:00] build their own device. That's the most sprinkler ish thing I can think of that. Doing, designing a fixed firefighting system to your own exactly known needs and possibilities. It's amazing. And.

[00:01:11] Wojciech Węgrzyński: Uh, it's interesting both for if you're dealing with sprinklers. Well, Actually, you may be a little angry because They did not go by the code for sure. But that's, that's also kind of far liberating in a way that they have defined. Uh, system for their needs. Not caring about. Anyone's opinion that it cannot be done. They they've just did it.

[00:01:35] Wojciech Węgrzyński: And they are very happy with it. Then the system works. So what else do you need to sounds like a really good investment. If you're an investor. So that's in today's episode and I just wanted to quickly tease on one more thing. That's coming up this week. on Friday, I will publish additional episode. Let's call.

[00:01:54] Wojciech Węgrzyński: Q and a. This time, it's me being questioned by professor Arnold Dix. It's very [00:02:00] non-fire science episode, because we're going to talk about. What happened in Poland after aggression on Ukraine. And I'm going to show you some of my own experiences and, And try to tell you how the situation looked in Poland for, for the last year. Uh, a lot of you are interested in what's happening in Ukraine. It's mess that the worst. Going for a year. And I guess that's my chance to, to share some stuff from the heart. In the podcast. So if you're interested in data, please check it out. It should publish on the, on Friday.

[00:02:29] Wojciech Węgrzyński: But please don't expect any fire science in that you will not find it there. Anyway. Let's go back to the fire science. Let's go back to the episode with Ulf Lundstrom from let's spin the intro and jump into the episode.

[00:02:42] Wojciech Węgrzyński: [00:03:00] Hey, so, you know, I can make the show thanks to the great support and receiving from my main sponsor this year, OFR Consultants.

[00:03:12] Wojciech Węgrzyński: If you have not met them yet. OFR consultants are a multi award winning independent consultancy dedicated to addressing fire safety challenges. OFR is the UKs leading fire risk consultancy and its established team has developed reputation for preeminent fire engineering expertise with colleagues working across the world to help protect people, property and planet.

[00:03:32] Wojciech Węgrzyński:

[00:03:32] Wojciech Węgrzyński: Internationally it's work ranges from Antarctic traffic.

[00:03:36] Wojciech Węgrzyński: And, you know what? I was actually very curious, what are they doing in Atacama desert in Sheila And as an amateur astro photographer myself. My gut feeling was correct. They are dealing with a very large telescope. Actually it's called the extremely large telescope observatory for the european organization for astronomical research

[00:03:53] Wojciech Węgrzyński: wow. That's one project I would like to eventually be involved in.

[00:03:56] Wojciech Węgrzyński: If this works sounds like something you would also like to do, or if [00:04:00] are as keen to hear from industrial professionals who would like to work on the fire safety features this year. Get in at ofrconsultants.com and now back to the episode with all phones from.

[00:04:09] Wojciech Wegrzynski: Hello everybody.

[00:04:10] Wojciech Wegrzynski: Welcome to Fire Science Show. Today I'm with Ulf Lundstrom from the Swedish Road Administration. Hey,

[00:04:16] Ulf Lundstrom: hello.

[00:04:17] Wojciech Wegrzynski: nice to meet you. And I, got a person from Administration, but let that not confuse you as a very good fire safety expert and, and someone responsible for, introducing sprinklers into a bunch of Swedish tunnels. Uh, this topic was sold to me by, by saying that Swedish, uh, have made a 180 degree turn in terms of the, of the safety concepts through introduction of fixed firefighting systems. So I would love to start, the, uh, discussion with the starting point of this, uh, 180 degree turn, like what was before the era uh, fixed firefighting [00:05:00] systems in Sweden. What was the. Environment looking like before you thought that we really need to introduce sprinters into our tunnels.

[00:05:08] Ulf Lundstrom: Uh, in Sweden, we were building a few, quite large, uh, urban tunnels with, uh, quite a lot of traffic. And the general concept is to build, longitudinal, ventilated, the tunnels and, uh, no fixed firefighting systems because at the time they, it was regarded as, uh, even dangerous and, and unnecessary.

[00:05:30] Wojciech Wegrzynski: Hmm.

[00:05:30] Ulf Lundstrom: So. we built two large tunnels, one in Gothenberg and one in Stockholm, especially.

[00:05:36] Ulf Lundstrom: The one in Stockholm turned out to be a problem. It was the Southern Link Tunnel. It's, uh, three kilometers from one end to another in oil. It's, uh, 15 kilometers of tunnel tubes in it. and we, uh, reached about, a hundred thousand vehicles per day in, in the tunnel. And that means it got quite congested and the traffic was moving very slow.

[00:05:59] Ulf Lundstrom: [00:06:00] And, since we had the longitudinal ventilated system, it meant if we had a fire, we risked that the cars would get trapped in the smoke downstream from the fire,

[00:06:11] Wojciech Wegrzynski: Hmm.

[00:06:12] Ulf Lundstrom: if we have a heavy good vehicle that's on.

[00:06:14] Wojciech Wegrzynski: This is a tunnel that's bypassing the city. What, how is it located?

[00:06:20] Ulf Lundstrom: it's, uh, under, uh, southern parts of Stockholm. So it's part of, uh, imaginary Ring Road that yet has to be completed. But it's the, the f the fir, yeah, the first leg of, uh, of the Ring Road.

[00:06:34] Wojciech Wegrzynski: Okay.

[00:06:34] Ulf Lundstrom: So it, opened for traffic in 2004.

[00:06:38] Wojciech Wegrzynski: when you were designing this tunnel, you, you have considered such a big traffic in it or.

[00:06:43] Ulf Lundstrom: not quite as big. And we, the knowledge in Sweden wasn't very big in tunnel safety issues, so we more or less relied on international expertise. So we built the tunnel like it's built everywhere else in the world, but, but it [00:07:00] turned out not to be very good in our traffic environment.

[00:07:02] Ulf Lundstrom: Or, or perhaps we had a, a fire brigade that was a bit more, uh, agile than, than to other parts of the world.

[00:07:09] Wojciech Wegrzynski: And, you at that point consider the congestion in the, the tunnel, or you thought it's gonna be fluid traffic and, uh

[00:07:16] Ulf Lundstrom: it was, uh, said it would be a free flowing traffic, but, I don't think anyone really believed that, considering what the traffic situation in Stockholm were at the.

[00:07:26] Ulf Lundstrom: what we do now is we, we actually have to close the tunnel down for safety reasons. Whe when there are too much traffic on the road network around the tunnel.

[00:07:36] Ulf Lundstrom: So that means it's closed down, uh, a few times every week. and that is very annoying for the motorists, using it for the commuting to the work. So it's a big problem.

[00:07:47] Wojciech Wegrzynski: I can imagine the, users of the tunnel be very happy to find out, uh, a tunnel, uh, with a hundred thousand, uh, vehicle traffic is being closed. That, that

[00:07:57] Ulf Lundstrom: Yeah,

[00:07:58] Wojciech Wegrzynski: uh, difficult. [00:08:00] let's talk you said it's, it's, it was for longitudinal ventilation, 2004.

[00:08:05] Wojciech Wegrzynski: What kind of design fire have you used? Were you already in the a hundred megawatt

[00:08:10] Ulf Lundstrom: It was a hundred megawatt.

[00:08:11] Wojciech Wegrzynski: Okay. So, so let's say you had a modern, modern ventilation system in it. Uh, why haven't you considered, uh, sprinklers as a safety measure at the, at the design stage?

[00:08:22] Ulf Lundstrom: it was, uh, considered, uh, not only by the Swedish Road authorities, by expertise in general in Europe, that, that is, was not. sufficient measure for a row tunnel, it was regarded as, uh, unnecessary or, or even dangerous

[00:08:36] Wojciech Wegrzynski: Okay.

[00:08:37] Ulf Lundstrom: it, you know, you got turbulence in, in the smoke layers, so, uh, you reduced visibility.

[00:08:43] Wojciech Wegrzynski: mix it? Yeah.

[00:08:44] Ulf Lundstrom: Yeah. and there was some very strange old, uh, tests that had been done where you managed to boil pigs by the steam. Dead pigs, I should say , but by this steam from, from a sprinkler in, in a closed environment. [00:09:00] So, so it was said that you, oh, you, you will burn all the vacuums by the steam, but, but that's absolutely not true.

[00:09:06] Ulf Lundstrom: You reduce the temperature.

[00:09:08] Wojciech Wegrzynski: 20 years later, I, I, I still, uh, hear some of these rumors when discussing the, the, this, uh, by evaporating, it's gonna take all the oxygen away from

[00:09:19] Wojciech Wegrzynski: the air and, and, and things, or that the visibility will drop so low you'll, uh, not be able to see. I, I usually responded I would like to not see and be wet rather than,

[00:09:29] Wojciech Wegrzynski: from a radiation.

[00:09:30] Wojciech Wegrzynski: But, uh, if I had a choice, I would choose that

[00:09:33] Ulf Lundstrom: certainly.

[00:09:34] Wojciech Wegrzynski: it's a system that you can use. so it was considered technically unfeasible and most likely it was also considered expensive at that point, right?

[00:09:42] Ulf Lundstrom: Yeah, certainly the installation costs and the cost for maintenance was a very big issue. so that meant that we, uh, had to look at ways to reduce the costs and, reduce the maintenance to get any kind of acceptance for, for this type of the system. In this, we destroyed the authorities.

[00:09:59] Wojciech Wegrzynski: [00:10:00] So I assume now comes your 180 degree turn

[00:10:03] Ulf Lundstrom: Yeah.

[00:10:04] Wojciech Wegrzynski: that, you are with, uh, the state of the tunnel that you would like to increase the safety. And because you already have state-of-the-art smoke control,

[00:10:12] Ulf Lundstrom: Yeah.

[00:10:13] Wojciech Wegrzynski: that can be done to improve that other than installing, uh, fixed firefighting

[00:10:18] Ulf Lundstrom: Yeah. So that, that was, in the next big tunnel project in Stockholm, the, the next part of the Ring Road in the Northern Link.

[00:10:25] Wojciech Wegrzynski: Okay.

[00:10:26] Ulf Lundstrom: So that was around 2009. Then the leading politicians in Stockholm said, we are not gonna build this tunnel the same way as, uh, the Southern Link, because we can't accept having a tunnel that's getting shut down.

[00:10:38] Ulf Lundstrom: And, that was in a very late stage of the tunnel project. It, the tunnel was already more or less built, so, uh, it was supposed to be open within five years. So we had to change the safety concept in, in a very late stage. So, We looked at it, uh, in a man. Many different ways. Uh, if you could do reg regulated [00:11:00] traffic so that you could get the cars to leave the tunnel quicker in case by fire, or if you could increase the detection, uh, systems capacity so you can detect the fire quicker.

[00:11:11] Ulf Lundstrom: But, we never got to a, a real, uh, robust safety concept with these measurements. So finally, we, we started to discuss, uh, fixed firefighting systems.

[00:11:21] Wojciech Wegrzynski: sounds like you, you were trying everything but sprinklers

[00:11:24] Ulf Lundstrom: Yeah, certainly because sprinkler, that, that was a dirty word, at that time.

[00:11:28] Wojciech Wegrzynski: don't use that word in, in,

[00:11:31] Wojciech Wegrzynski: Right.

[00:11:31] Ulf Lundstrom: exactly.

[00:11:32] Wojciech Wegrzynski: uh, I assume you have not went to the nearest sprinter shop to purchase sprinklers. as I've read some of your materials, it seems that you went quite a triplet road by, by figuring out

[00:11:43] Ulf Lundstrom: Uh, yes. Turbulent or, or a very easy road, depends on how, how you look at it. Um, because, uh, as I the sprinkler systems or the fixed firefighting systems that were on the market around 2010, they, they were, uh, dismissed already. They were regarded as [00:12:00] not, uh, sufficient to be in the Swedish tunnel.

[00:12:02] Ulf Lundstrom: So we had to come up with something new to, uh, get acceptance.

[00:12:06] Wojciech Wegrzynski: Hmm

[00:12:06] Ulf Lundstrom: So, uh, we looked what the, the tunnel itself looked like. We already had water system installed, the fire hydrants for the fire brigade, and there was quite a lot of water that could be delivered in them.

[00:12:19] Wojciech Wegrzynski: Hmm

[00:12:20] Ulf Lundstrom: so we, looked at the possibilities to just make something very simple, some kind of IKEA system just to, spray water, uh, directly from the hydrants out in the tunnel.

[00:12:31] Ulf Lundstrom: And, uh, by then we didn't look so much at the sprinkler regulations. We just looked what was, uh, physical possible in the tunnel. What could we do to achieve the such? Robust and, efficient system. Cost efficient system as possible.

[00:12:47] Ulf Lundstrom: first we decided what do we want to build? And, and, looked at that and especially how much water do we have and how can we distribute that in an efficient way over the tunnel?

[00:12:58] Ulf Lundstrom: And then we started to [00:13:00] look, alright, what does the sprinkler regulation say about this? When we saw. We, we can't build a sprinkler like this. So then we had a choice, all right, forget the whole thing. Or, or we can forget the sprinkler regulations. And we, we chose to not call it a sprinkler, we just call device to spray water in case we fire.

[00:13:18] Wojciech Wegrzynski: I my listeners, uh, from the sprinkler industry have not died of a heart attack after this last sentence. uh, I find it very uncommon, uh, to go, and do a that, that essentially is a sprinkler system, not following. the guidelines, you know, sprinklers, sprinklers is a part of fire engineering that. Maybe even the, the, the first active system ever that, that originates 150 years ago. You know, it was all built in experiment in an experimental setting by burning and proving that, that that something works then codifying it, you know,

[00:13:54] Ulf Lundstrom: Yeah.

[00:13:55] Wojciech Wegrzynski: and standards that, that regulate the, the whole thing up [00:14:00] to the tiniest details of, of mounting and everything

[00:14:02] Ulf Lundstrom: Yeah. And perhaps that, perhaps that is the problem. it's difficult to adapt the technology to a new environment.

[00:14:10] Wojciech Wegrzynski: Exactly.

[00:14:10] Ulf Lundstrom: So, so we thought that, uh, when we looked at the needs for, for our road tunnels, the sprinkler regulations wasn't really up to, up to date. They, they need to be developed.

[00:14:20] Wojciech Wegrzynski: I think, uh, perhaps he even went into more, how to say it. Uh, Origin way of, of designing sprinters, you know, trial by fire,

[00:14:32] Ulf Lundstrom: Yeah, certainly.

[00:14:33] Wojciech Wegrzynski: down and, and designing, up to need. Maybe

[00:14:37] Wojciech Wegrzynski: the more, how sprinklers were. Were born so, so act actually, I, I believe a lot of, uh, people will appreciate that.

[00:14:45] Wojciech Wegrzynski: So, but, but let's, let's talk about this un feasibility of, of the existing solutions. So there are very different, uh, sprinkler solutions for different demands. Even e early suppression, fast response, E SF r sprinklers uh, that [00:15:00] can deliver enormous amounts of, of water. There are all types of water sprays that you can use.

[00:15:06] Ulf Lundstrom: Yep.

[00:15:07] Wojciech Wegrzynski: Like, so, so, so you were sure that none of the existing solutions would fit. Why? Why? Why would that not, not,

[00:15:13] Ulf Lundstrom: It was a lot of, uh, cost benefit discussions.

[00:15:18] Ulf Lundstrom: So, um, we are building in the Northern Link. It was, as I said, uh, total 15 kilometers autonom tubes that should be fitted with the system. So, so it's very important to, so to get a layout that is, cost-effective.

[00:15:32] Wojciech Wegrzynski: Hmm.

[00:15:32] Ulf Lundstrom: and the most cost effective way to build the pipes in the tunnel is just one pipe in the center of the ceiling.

[00:15:40] Ulf Lundstrom: and just, feed it from, uh, each, uh, escape route, which we have, uh, 150 meters, distance in the Northern Link. So that meant the most cost effect layout that was, uh, 75 meter long del loose section, half the way to next, escape [00:16:00] route. and, there was no, existing, uh, concepts that, could, build the, uh, section that looks like that within the regulations.

[00:16:07] Ulf Lundstrom: So if we wanted to build that, cost effective layout, we had to break the regulations.

[00:16:12] Wojciech Wegrzynski: You are the regulations.

[00:16:15] Ulf Lundstrom: Yeah.

[00:16:16] Wojciech Wegrzynski: That's, that's a very lucky position.

[00:16:19] Wojciech Wegrzynski: the, in the materials. you, you sent me, uh, there's a very striking thing. Related to this section. So if you have a 75 meter long section, you, uh, had the capacity because you were, as you said, you, you already had the design very far advanced, so you were really capable of densities of five millimeters per minute. that's very like, Low, uh, capacity for large, hazard in high storage systems,

[00:16:46] Wojciech Wegrzynski: for much, much higher, uh, uh, values. And, in this article you sent me, you were saying that For a high risk storage warehouse, you really need, these high values, like okay, [00:17:00] the, the high rise storage, uh, maybe somehow imitates the conditions within the tunnel in terms of the fire load.

[00:17:06] Wojciech Wegrzynski: In terms of the material in the tunnel. I just had Haukur Ingason who, who said that when he went. A tunnel. He's so like, uh, saw commodities, but on a truck. And that, that gave him inspiration to do these Runehammar or tests. So indeed, there are similarities. However, the goal of a system in, in, in warehouse is very different than the goal from

[00:17:29] Ulf Lundstrom: yeah. Certainly in, the normal warehouse, the, the reason you put in the sprinkler system is to protect your facility, to save the, the building and the goods in the warehouse. , in the row tunnel we are trying to slow down the, the fire growth just to buy us time to evacuate the tunnel and to, have a small fire for the fiber to attack.

[00:17:51] Ulf Lundstrom: We are not trying to put it out like you were do in a sprinkler system in the warehouse. So, so we have a different, uh, ambition [00:18:00] than, than you have in, in the normal, sprinkler regulat.

[00:18:03] Wojciech Wegrzynski: So by acknowledging you are unable to, uh, achieve the complete suppression or the full safety goal, of a warehouse sprinkler system, you, you also acknowledge that, you're okay by just slowing the fire or,

[00:18:16] Ulf Lundstrom: Yeah.

[00:18:17] Wojciech Wegrzynski: any, any kind of. Benefit a typical sprinkler, uh, would give you, and, and you are fine with, uh, with the fact that it will not be perfectly efficient against any fire we can meet.

[00:18:29] Wojciech Wegrzynski: And I

[00:18:30] Wojciech Wegrzynski: it also probably comes down to the. Probability of fires and the probability it'll be large fire. I guess we'll touch that, uh, at the later stage of the podcast, discussing your with this, uh, built and used, uh, system. but, but to continue on the design of the, system.

[00:18:48] Wojciech Wegrzynski: So the objective was to build up time for evacuation. The objective was to create, um, conditions in which the firefighters can advance in the tunnel. [00:19:00] Somewhere in the papers there's, um, mentioning of reducing this a hundred megawatt to approximately 30 megawatts, which

[00:19:09] Ulf Lundstrom: Yeah, that's.

[00:19:10] Wojciech Wegrzynski: more manageable.

[00:19:11] Ulf Lundstrom: Yeah.

[00:19:12] Ulf Lundstrom: yeah, that's the dimensioning, uh, for the fire ventilation in the tunnel. That's 30 megawatts.

[00:19:17] Wojciech Wegrzynski: Okay, so, okay, so, so you also included that in, so that's a cost effective solution

[00:19:23] Wojciech Wegrzynski: make a significantly smaller system, which probably pays a lot of the costs of the,

[00:19:28] Ulf Lundstrom: Yeah, certainly.

[00:19:29] Wojciech Wegrzynski: So, so tell me about development of that you come in at the very late stage of the Pro project how do you, design the solution and how do you. Verify that the solution that you are designing is actually meeting these new goals and objectives you've set.

[00:19:45] Ulf Lundstrom: Yeah. Uh, as I said, we, we started to look at what do we want to build in the tunnel, and then we started to do some practical tests, but what can that achieve that we, that we want to build? And, we were surprised [00:20:00] actually by what we achieved at the tests. We, we used to work quite a lot with the, Haukur as, who you talked to earlier.

[00:20:08] Ulf Lundstrom: so they were both, uh, scale tests and, uh, full scale tests with different types of nozzles. Uh, we were very happy to see the performance of these, low pressure sideway nozzles. because they create large droplets. And that's, uh, quite opposite what you usually say. You, you, if you lo listen to the water mis industry, they say you, you must have small droplets to cool down efficiently.

[00:20:35] Ulf Lundstrom: But that depends on what you want to cool down. If you want to cool down a surface, then you need a big droplet that penetrates all the way down to that surface and hit it and then get a large, uh, area when it's, uh, shattered in a smaller, smaller droplet. . And, if you get these large droplets to penetrate all the way down to the fuel in the fire, then you get to very efficient, suppression of [00:21:00] the fire.

[00:21:00] Ulf Lundstrom: So that, that's something we have seen actually at the, the larger droplets, the, the more efficient, uh, suppression we get.

[00:21:06] Ulf Lundstrom: and makes us, quite safe with these, uh, only five millimeters per meter per uh, minute.

[00:21:12] Wojciech Wegrzynski: Okay, because you, that you are sure that, uh, these five ERs are actually delivered to the fuel because

[00:21:19] Wojciech Wegrzynski: droplets and they have a large momentum

[00:21:22] Wojciech Wegrzynski: the buoyant smoke.

[00:21:23] Wojciech Wegrzynski: that, that's interesting. And, the efficiency of this solution, it was tested by, by trialed, by fire, right?

[00:21:28] Ulf Lundstrom: Yeah.

[00:21:29] Ulf Lundstrom: it was both, scale tests and laboratory tests down RISE in Boras and we also made, uh, full scale tests in Runehammar in Norway. there's, uh, abandoned road tunnel where you can, uh, conduct full scale tests up to a hundred megawatts.

[00:21:44] Wojciech Wegrzynski: We, we were just discussing that with, with Haukur

[00:21:48] Ulf Lundstrom: yeah,

[00:21:48] Wojciech Wegrzynski: fascinating. May maybe you can tell us a little more about these experiments, like what you've put in the tunnel and, and how did the sprinklers, worked there? Like what was the achieved?

[00:21:57] Ulf Lundstrom: yeah. We, we tried to [00:22:00] simulate, full scale, uh, heavy goods vehicle, the same type as he burned down in, uh, 2003. So there were.

[00:22:08] Wojciech Wegrzynski: wooden pettes and stuff.

[00:22:09] Ulf Lundstrom: exactly. Four, 420 wooden pallets. And we had, uh, steel roof on top of it to challenge the sprinkler system more. And then there were open sides to, to get, uh, enough air into the, the fire.

[00:22:24] Ulf Lundstrom: So, so you could reach these a hundred megawatts. That's the potential

[00:22:28] Wojciech Wegrzynski: mm-hmm.

[00:22:28] Ulf Lundstrom: peak of heat release rate.

[00:22:31] Wojciech Wegrzynski: and, and what was achieved.

[00:22:32] Ulf Lundstrom: Uh, yeah, it, it depends on when, when you start the, the system. we did a few tests with, uh, these small noles for the Northern Links. We also did other tests with larger, nozzles for, uh, later tunnel projects. But, but with this, s Suite 24 noles for five millimeters per minute, we, we achieved, controlling the fire at around, 30 megawatts, you know, potential a hundred megawatts fire.

[00:22:58] Wojciech Wegrzynski: So this, uh, [00:23:00] primary, uh, goal that also went in the design of smoke control system was, was achieved,

[00:23:04] Ulf Lundstrom: Yeah. We could verify that's

[00:23:08] Wojciech Wegrzynski: significantly down

[00:23:09] Ulf Lundstrom: And then we also Quite a lot of tests in, uh, an existing row, tunnel where we had put up some, uh, test rigs so we could use, uh, different nozzles. And uh, also there we had help from, uh, rise and, uh, we measured temperature at, uh, different surfaces around the. and there we could see it didn't really matter if you had 10 millimeters per minute or five millimeters per minute.

[00:23:36] Ulf Lundstrom: The surface that got sprayed with water never reached more than 70 degrees anyway

[00:23:42] Wojciech Wegrzynski: Okay

[00:23:43] Ulf Lundstrom: you water floating at it. So you can't, uh, physically, uh, go over a hundred uh, degrees.

[00:23:48] Wojciech Wegrzynski: and, You've mentioned about a system with a single pipe, uh, going through the central point of the tunnel.

[00:23:56] Wojciech Wegrzynski: also mentioned, um, a sideways spraying [00:24:00] sprinklers.

[00:24:00] Ulf Lundstrom: Yeah.

[00:24:01] Wojciech Wegrzynski: how about the obstructions and the impact obstructions can have, I mean, you can have, uh, multiple trucks and, and very complicated

[00:24:07] Wojciech Wegrzynski: geometry in

[00:24:09] Ulf Lundstrom: Yeah. you, you could have, uh, large obstructions and small obstructions. when we look at small obstructions such as, uh, road signs or uh, lamps or these kind of things, then, then we are not really worried because. There are relatively small, uh, areas that are, uh, shaded by these obstructions.

[00:24:31] Ulf Lundstrom: So, uh, it has to be a really small fire to, uh, not be reached by the water. And, and we are not really bothered about small fires. It's, it's the big ones we are, uh, fighting. , but then you also could have a large, uh, obstruction, you said, heavy goods vehicle. And, and that is, uh, very important. you must, look at the risk that you have, uh, uh, 4.5 meter high, uh, heavy goods vehicle in the tunnel.

[00:24:54] Ulf Lundstrom: So the system, the, the demands we have on the system is that it must put water [00:25:00] on top of such a vehicle. So you get water on top of the roof and then it pours down on the side of it. Both sides. So even if it's, uh, sort of shaded because you have a sideway sprinkler, it, it gets down to the opposite side of the of the vehicle anyway.

[00:25:17] Wojciech Wegrzynski: you're not focused on having the most perfect performance, but

[00:25:22] Ulf Lundstrom: yeah. Good

[00:25:23] Ulf Lundstrom: enough.

[00:25:25] Wojciech Wegrzynski: performance to to prove, to have evacuation and rescue operations, which then. targets the, the sites which are shielded to something.

[00:25:33] Wojciech Wegrzynski: guess this is a big, uh, a big difference because, uh, if you were focused primarily on very uniform water distribution, it, it happens in, in, in sprinkler testing that we would be very focused on, on how, delivery of water is distributed, was the initial spray pattern.

[00:25:51] Wojciech Wegrzynski: Where, where does the water go? Here it seems you had this performance objective behind your head all the

[00:25:59] Wojciech Wegrzynski: time

[00:25:59] Ulf Lundstrom: Yeah, [00:26:00] certainly. it's preventing fire spread. That's the important stuff. You should get everything as wet as possible while the fire is still small, that that's the key issue here.

[00:26:11] Wojciech Wegrzynski: Again, it's, it's very helpful that, you are setting the goals

[00:26:15] Ulf Lundstrom: Yeah, certainly.

[00:26:17] Wojciech Wegrzynski: you are a who wants to sell, uh, someone's solution. So that's a very different set up and I actually appreciate this setting a lot. It, it, It seems to allow a true performance based engineering of, of the system.

[00:26:30] Ulf Lundstrom: Yeah.

[00:26:32] Wojciech Wegrzynski: the Ru hammerer tests gave different outcomes depending on the time of activation. So, uh, how, how is the trigger of the system decided and how do you know where to fire the the,

[00:26:43] Wojciech Wegrzynski: system

[00:26:44] Ulf Lundstrom: Yeah. Well, our tunnels are, uh, supervised by, uh, a man control central. And, as soon as they, uh, verify that there is a fire in the tunnel that they start, uh, pre-action plan for the fires, and that includes activating [00:27:00] the fixed firefighting system immediately. So, after verifying the fire, it takes about 30 to 40 second before the first water reached, uh, the tunnel.

[00:27:11] Ulf Lundstrom: of course the early detection is very important. So we have a lot of different systems now tunnels to detect the, the incident. We, of course we have the stop, stop vehicle detection systems. We have, uh, smoke alarms in our cameras. If you suddenly get, lower visibility, but you get an alarm, we got heat sensing cables.

[00:27:33] Ulf Lundstrom: and of course we full mobile telephone coverage in the whole tunnel. That's often the quickest way we get to know about the fire that, uh, someone calls.

[00:27:41] Wojciech Wegrzynski: the decision about triggering this sprinkler system is, decision uh, personnel

[00:27:45] Wojciech Wegrzynski: or

[00:27:46] Ulf Lundstrom: yeah.

[00:27:46] Wojciech Wegrzynski: automated

[00:27:47] Ulf Lundstrom: Uh, that, that is, uh, automatic, solution as well. I, if the temperature in the heat sensing cable reach very high levels, then, then it activates, uh, automatically, but that's, uh, about [00:28:00] 70 to 90 degrees, something like that. It's, very high. so then you have a real disaster in the tunnel.

[00:28:05] Wojciech Wegrzynski: So I guess, uh, there is much higher chance that it will be already observed by cameras

[00:28:09] Wojciech Wegrzynski: automated, uh, incident detection. So it'll tell you there's a stop vehicle. I guess the cameras zoom on that. So, so the, the people, administrators know. Fantastic.

[00:28:19] Ulf Lundstrom: and the, one more thing about these, large droplets, uh, they also give us a very good visibility through the activated section.

[00:28:27] Ulf Lundstrom: Uh, and that's very important if you want to activate it immediately so we don't have to wait for the traffic to stop or, uh, the people to activate by foot before reactivated.

[00:28:39] Ulf Lundstrom: It's just the second you see the verify that there is a fire or a probable fire, then, then you just start the.

[00:28:45] Wojciech Wegrzynski: Have you ever tried to drive through such a

[00:28:47] Ulf Lundstrom: Yeah. Suddenly, many

[00:28:49] Wojciech Wegrzynski: a guy who you look like a guy

[00:28:51] Wojciech Wegrzynski: who would try that

[00:28:52] Ulf Lundstrom: Yeah, we, we did that. And also unfortunately, the motorist in Stockholm also try that. So when we have had real fires, [00:29:00] they don't stop. Although we give them the signs in, in the ceiling, you know, these red crosses that they must stop.

[00:29:06] Ulf Lundstrom: And the radio. Transmissions and, text signs, they, they just keep driving through the activated sections into the smoke and out of the tunnel.

[00:29:15] Wojciech Wegrzynski: And how

[00:29:16] Ulf Lundstrom: So,

[00:29:17] Wojciech Wegrzynski: have a rain

[00:29:17] Wojciech Wegrzynski: or

[00:29:18] Ulf Lundstrom: yeah, r really heavy rain.

[00:29:20] Ulf Lundstrom: But, uh, if, if you have a car in front of you, then it's no problem. It's just like driving through a snowstorm. You, you follow the taillights of the coral in front of you.

[00:29:29] Ulf Lundstrom: are the first car, then it's more, uh, , then it's more challenging.

[00:29:32] Wojciech Wegrzynski: So So, it's not the worst weather conditions a driver can find in Sweden,

[00:29:36] Ulf Lundstrom: No

[00:29:38] Wojciech Wegrzynski: Certainly. mentioned, uh, at the beginning that, you wanted the water delivery system. That's, that's simple. And, and,

[00:29:47] Wojciech Wegrzynski: this robustness. Like what, what were the factors in simplifying the system outside of using the existing hydrant system feed with

[00:29:54] Wojciech Wegrzynski: water

[00:29:55] Ulf Lundstrom: Well, you know, by using very long sections, then, then you reduce the number [00:30:00] of moving parts that you have to, uh, look after. And also, uh, there was, discussions about putting in the extra valves that you, you could test the valves without, getting any water out in the real tunnel so you can test activate it while, while there's traffic, in the tunnel.

[00:30:18] Ulf Lundstrom: But we choose not to have that kind of systems we, because then we add another risk of failure. so we, we really want to keep it as clean and simple as possible. Reduce the number of moving pots as far as you ever could go. Now we just have two moving parts in the whole system. The, the big rubber membrane valve and the electric.

[00:30:39] Ulf Lundstrom: So night valve that operates all of

[00:30:41] Ulf Lundstrom: it.

[00:30:42] Wojciech Wegrzynski: and the the pressure comes

[00:30:43] Wojciech Wegrzynski: from the

[00:30:44] Wojciech Wegrzynski: from from what

[00:30:45] Ulf Lundstrom: In the Northern Link, it's just, attached to the water city water supply net. So there's no pumps, it's just normal water

[00:30:52] Wojciech Wegrzynski: what what kind of

[00:30:53] Wojciech Wegrzynski: pressure does it

[00:30:53] Wojciech Wegrzynski: operate at

[00:30:54] Ulf Lundstrom: we get about, five or six bars into the tunnel system and, [00:31:00] uh, in the nozzles we have two bars or something like that.

[00:31:05] Wojciech Wegrzynski: Straight out of the the city network.

[00:31:07] Ulf Lundstrom: Yeah.

[00:31:08] Wojciech Wegrzynski: That's good. what, what about the, um, corrosion? The, the tunnel is not a very nice environment.

[00:31:15] Wojciech Wegrzynski: is it

[00:31:16] Wojciech Wegrzynski: like stainless

[00:31:16] Wojciech Wegrzynski: steel pipes Uh

[00:31:17] Ulf Lundstrom: yeah, we, we looked at that first, but then we actually chose to go for a pre-manufactured, plastic coated, uh, steel pipes.

[00:31:27] Wojciech Wegrzynski: Mm-hmm

[00:31:28] Ulf Lundstrom: So, uh, it's called Alvenious uh, pipes. So they are plastic coated both on the inside and outside and the at the end. So there are no exposed metal anywhere,

[00:31:39] Wojciech Wegrzynski: Uhhuh I see

[00:31:40] Ulf Lundstrom: and, and that gives us, uh, a possibility to, uh, use, uh, Couple links to, build the system.

[00:31:48] Ulf Lundstrom: So you just have a, a wrench, number 13 wrench. That's all you need to build the complete system. So it's, again, IKEA version. So there's no, no welding or anything when we build the system. [00:32:00] It's just, uh, bolted together. And that,

[00:32:03] Ulf Lundstrom: very good. If you damage in the tunnel, some, some sort of, uh, accident or incident, then it's very easily to.

[00:32:09] Wojciech Wegrzynski: Fire protection system delivered in a, in a flat package.

[00:32:13] Wojciech Wegrzynski: nice. so, so now let's talk about your experience as a user of these devices. So,

[00:32:20] Wojciech Wegrzynski: before you said that there. was that it will be very, expensive to test, maintain, uh, fix, audit.

[00:32:28] Ulf Lundstrom: Yeah.

[00:32:29] Wojciech Wegrzynski: what, what's your experiences against that of this, this custom-built

[00:32:34] Wojciech Wegrzynski: systems in

[00:32:34] Wojciech Wegrzynski: in your network

[00:32:36] Ulf Lundstrom: Yeah. we we're actually very happy of, of course, all this testing were, uh, quite expensive, this development of, of the system. But, uh, if you look at that as a once, cost, then, then we use this concept over and over again in different tunnels. So, so the more systems we built, the, cheaper it gets.

[00:32:54] Wojciech Wegrzynski: Hmm

[00:32:55] Ulf Lundstrom: the, the audit part of it's also no big deal actually be because we [00:33:00] did these very good, uh, tests together with rice and Haukur uh, and they are sort of world leading expertise. So, so no one could argue with, with their results and their conclusions that, that this system actually performs, uh, as we wanted.

[00:33:14] Ulf Lundstrom: and, and when it comes to, uh, maintenance, uh, we, test every section once a year in the Northern Link. If we had followed the sprinkler regulations we would have had, uh, certified, controller doing, tests four times a. . And since we have, uh, something like 300 sections, we would've a full-time guy going there all the time.

[00:33:38] Wojciech Wegrzynski: But, uh,

[00:33:39] Wojciech Wegrzynski: testing you mean using a separate valve

[00:33:41] Wojciech Wegrzynski: or or just

[00:33:41] Wojciech Wegrzynski: releasing the water through

[00:33:43] Ulf Lundstrom: the, the tunnel is shut for maintenance, so there's no traffic. So, so we, open it fully. Yeah. And then we look at the, the spray pattern that it's okay, we don't have any damage, no salts or something like,

[00:33:54] Wojciech Wegrzynski: Very interesting. Very interesting. uh, now tell me about the real incidents. So do you have them for, [00:34:00] for some use, I guess

[00:34:01] Wojciech Wegrzynski: there were some

[00:34:01] Wojciech Wegrzynski: fires in in these

[00:34:03] Ulf Lundstrom: Yeah, we in the Northern Link, we have around, one fire every year. So I think we have, uh, seven or eight, uh, fires now. And, usually it's, uh, just, uh, normal cars. this spring we something a little bit more challenging. Uh, we had a camper van that caught fire after collision

[00:34:22] Ulf Lundstrom: and, uh,

[00:34:24] Wojciech Wegrzynski: vehicle

[00:34:25] Ulf Lundstrom: yeah, suddenly, and it's glass, fiber and plywood.

[00:34:28] Ulf Lundstrom: So, it was not a steel, uh, steel vehicle. so that was, uh, potentially quite a very big fire, the system operated as, uh, it was supposed to. it didn't put out the fire, but uh, it controlled it. So, so the situation was not very dramatic. Haukur looked at the pictures afterwards and he concluded that, uh, it reached about 10 megawatts, uh, in the.

[00:34:55] Wojciech Wegrzynski: mm

[00:34:56] Ulf Lundstrom: And, uh, if it had been a free burning vehicle, we'll [00:35:00] have to fix firefighting system. We probably would've reached over 30 megawatts and the vehicle would've been completely destroyed. Now, this was quite a lot of fuel left that hasn't burned

[00:35:10] Wojciech Wegrzynski: very

[00:35:11] Wojciech Wegrzynski: And, and, how does it work along with the longitudinal ventilations? Like is there any negative interaction between the

[00:35:18] Wojciech Wegrzynski: systems

[00:35:19] Ulf Lundstrom: No, I, I think it's actually, uh, performing better when you have the ventilation running. We, we have, uh, even increased, uh, air speed in the action plan. So now we are running it, uh, three meters per second, uh, all the time, no matter the traffic situation downstream. Because you create turbulence when you have the high air speed, and that means that the water gets into, uh, different parts of the vehicle in another way.

[00:35:45] Ulf Lundstrom: So I think it's, uh, very good to, to have the longitudinal ventilation.

[00:35:50] Wojciech Wegrzynski: Coming back to that, uh, camper fire. What was the exact damage to the tunnel and its systems

[00:35:57] Wojciech Wegrzynski: from such

[00:35:58] Wojciech Wegrzynski: a fire

[00:35:58] Ulf Lundstrom: There was, uh, [00:36:00] some damages to cables on a cable tray just, immediately above the vehicle because, they, they drove, uh, at, at side when, when the accident happened. So, so they stood right under the cable tray. So there, there were some cables that got burnt and then there was a large road sign that got some suit and, heat damage, but we, we could open the tunnel within two hours after the fire

[00:36:27] Wojciech Wegrzynski: hours. Wow.

[00:36:29] Wojciech Wegrzynski: that,

[00:36:29] Ulf Lundstrom: So,

[00:36:30] Wojciech Wegrzynski: resilience.

[00:36:31] Ulf Lundstrom: uh, and then it was also a police investigation, so perhaps we could have, uh, opened it even quicker if it was just because of the fire reason.

[00:36:40] Wojciech Wegrzynski: Have you left the sprinklers, watered the the police as

[00:36:43] Ulf Lundstrom: Yeah, we should have, so, so we got them after the tunnel. Yeah.

[00:36:47] Wojciech Wegrzynski: I don't want to be nasty, but

[00:36:49] Wojciech Wegrzynski: would do

[00:36:50] Ulf Lundstrom: Yeah.

[00:36:51] Wojciech Wegrzynski: Uh, Um, you said it was on the side of the road where the, the, the camper stopped.

[00:36:57] Ulf Lundstrom: Yeah.

[00:36:58] Wojciech Wegrzynski: uh, and you had [00:37:00] this single, uh, single pipe system

[00:37:02] Wojciech Wegrzynski: to the middle. So

[00:37:04] Wojciech Wegrzynski: effects and everything. And, and, uh, no observed, negative interference of

[00:37:08] Wojciech Wegrzynski: that.

[00:37:09] Ulf Lundstrom: No, I think the system worked, uh, as, uh, expected. the, that Noel can throw, uh, 7.5 meters, uh, sideway and we have them back to back in the center of the tunnel, so we could cover up to a 15 meter wide tunnel. And, uh, this tunnel, it was just two lanes, so I think it was, roughly 12 meters wide.

[00:37:29] Ulf Lundstrom: So, uh, we, there was still some margins we could.

[00:37:32] Wojciech Wegrzynski: so now for the end, I would love to talk about resilience. you said that you've opened the tunnel two hours after the incident. That that

[00:37:40] Wojciech Wegrzynski: That's amazing resilience. I, I had an episode of the podcast with, engineer Ingo Reiss who was talking about, uh, resilience in tunnels and, uh, use of what suppression system's to provide that. I didn't hear when you were telling me the reasons, uh, didn't list resilience as one of the reasons, like you

[00:37:58] Ulf Lundstrom: No,[00:38:00] uh, certainly now it's one of the most important aspects actually.

[00:38:04] Wojciech Wegrzynski: Hmm.

[00:38:05] Ulf Lundstrom: it's, if you look at the socioeconomical costs of a large fire, then, then it's, uh, certainly in, in favor of a fixed fire fighting system really.

[00:38:14] Wojciech Wegrzynski: And you put sort of socioeconomical cost in the considerations, uh, for, for the future tunnels. I should ask, will you put this type of devices

[00:38:23] Wojciech Wegrzynski: in all your tunnels now?

[00:38:24] Ulf Lundstrom: unfortunately a as, things are right now. It's when we expect, traffic congestions whe when the, personal safety, requires, uh, these type of measures. . But, uh, yeah, we have one tunnel that is, being fitted with the fixed five fighting system for, uh, socioeconomical reasons. And that is a old tunnel thing, stud tunnel.

[00:38:46] Ulf Lundstrom: It goes under a river in central Gutenberg, so it's, uh, sink tunnel. You know when you have a, a concrete box that you drop down on the bottom of the,

[00:38:57] Ulf Lundstrom: the river?

[00:38:57] Ulf Lundstrom: that old, uh, [00:39:00] concrete, uh, construction, it, it can't take a large fire. So, so then we could lose the whole tunnel. So therefore we are, uh, fitting it with a fixed firefighting system.

[00:39:09] Ulf Lundstrom: So,

[00:39:10] Ulf Lundstrom: yeah.

[00:39:10] Wojciech Wegrzynski: And what's the future for the, uh, Soutehrn link, uh,

[00:39:14] Wojciech Wegrzynski: tunnel. The one

[00:39:15] Wojciech Wegrzynski: we've started with

[00:39:16] Ulf Lundstrom: Yeah, we we're looking at it. We, we have, uh, several challenges with this, tunnel. As I said, it's a hundred thousand vehicles per day, so you can't just shut it down and start mounting, uh, of the expired fighting system cause people will get crazy. So, so you have to do it that nighttime and you have to have some sort of traffic running in the tunnel.

[00:39:37] Ulf Lundstrom: So therefore, we are looking at the system where we. Cover the whole cross section of the tunnel from one side. And, also the tunnel ceiling is constructed in such a way that we are not allowed to touch anything in the ceiling. So we have to mount the pipes on the wall somehow. Yeah,

[00:39:56] Wojciech Wegrzynski: throw, throwing water from

[00:39:57] Wojciech Wegrzynski: the side,

[00:39:57] Wojciech Wegrzynski: uh, on the middle

[00:39:59] Ulf Lundstrom: that [00:40:00] tunnel is, 15 meters wide.

[00:40:01] Ulf Lundstrom: So, so we have to develop some sort of noles that can through, uh, 15 meters. As I said, we are between, uh, seven or nine meters, uh, in the existing nozzles, but we're, we're looking at means to, to increase

[00:40:15] Ulf Lundstrom: this.

[00:40:15] Wojciech Wegrzynski: And if you find a solution, you intend to install that under the traffic and just, uh,

[00:40:21] Ulf Lundstrom: Yeah.

[00:40:22] Wojciech Wegrzynski: That's very interesting. if, if you start doing that, I will, I would love to see that. Maybe I'll come to, to Stockholm

[00:40:28] Ulf Lundstrom: Certainly

[00:40:29] Wojciech Wegrzynski: Uh,

[00:40:30] Ulf Lundstrom: I'll

[00:40:30] Ulf Lundstrom: keep in touch.

[00:40:31] Wojciech Wegrzynski: Thank you very much. Uh oh. That was, uh, very insightful.

[00:40:34] Wojciech Wegrzynski: I, I hope that the people from sprinkle industry are still listening

[00:40:39] Wojciech Wegrzynski: episode. I am pretty sure a large chunk of them has, uh, switched the radio at some point

[00:40:45] Ulf Lundstrom: Yeah.

[00:40:46] Wojciech Wegrzynski: of the blasphemy you were saying here. But, uh, I found it very interesting and it, I think it's one of a. Few, true performance engineering projects that, that go beyond and above for [00:41:00] codes and standards in the sprinkler industry.

[00:41:02] Wojciech Wegrzynski: Very, a very interesting, um, case study. possibly interesting to, to repeat in, in other places of the worlds. I know you are having a keynote at I S T S S conference. so,

[00:41:15] Ulf Lundstrom: That's right.

[00:41:17] Wojciech Wegrzynski: If someone would like to hear more about these tunnels, plus see the videos, visuals, and learn more, I guess that is a great, uh, place to meet, uh, with you and, and learn more.

[00:41:29] Ulf Lundstrom: Certainly.

[00:41:30] Wojciech Wegrzynski: to read about the developments of these systems, is it possible? Are the reports

[00:41:35] Wojciech Wegrzynski: published?

[00:41:35] Ulf Lundstrom: Yeah, E everything is, uh, official. So, so either you can go, buy RISE or, or they can, uh, just Google it. if, you can't find it, uh, that, that will be ways to find it. Not nothing is, uh, secret.

[00:41:49] Wojciech Wegrzynski: Fantastic. Uh, if it exists in the, in in the internet, I will then link it to the show notes of this episode so

[00:41:57] Wojciech Wegrzynski: can just by one click, uh, find the links to [00:42:00] read more. Tha thank you so much o for coming to, to the podcast and sharing your experience, uh, with us.

[00:42:06] Ulf Lundstrom: All right. Thank

[00:42:07] Wojciech Wegrzynski: suddenly pass your experience to the polish or administration because it sounds like a very

[00:42:12] Ulf Lundstrom: Yeah. Nice.

[00:42:14] Wojciech Wegrzynski: and

[00:42:14] Wojciech Wegrzynski: developments you

[00:42:15] Wojciech Wegrzynski: have done. Very

[00:42:16] Ulf Lundstrom: A actually, the, the similar system is, uh, being put in one of your tunnels after wa heard. So,

[00:42:23] Wojciech Wegrzynski: so that's, so that's the one. Okay, that's interesting. We, we have just one tunnel that's, that's employing sprinklers right now. So I know which tunnel we were talking about.

[00:42:31] Ulf Lundstrom: Okay.

[00:42:32] Wojciech Wegrzynski: That's great. Then, then I may have a chance to see it in action sooner than I thought. Uh,

[00:42:37] Wojciech Wegrzynski: that one is, is being built right now. Uh, ooh, thank you so much and,

[00:42:43] Wojciech Wegrzynski: uh, see you around

[00:42:44] Ulf Lundstrom: Okay. Yeah. Thank you. See you

[00:42:47] Wojciech Węgrzyński: And that's it. Thank you for listening. I wonder what's more important in this episode. The technology of deluge system they are using in their tunnels. Which works at very low water intensity and actually [00:43:00] allows them to achieve their goal of slowing down the fire. So the fire brigade may enter extinguisher. It protects people and lost them. Save escape that that's actually.

[00:43:09] Wojciech Węgrzyński: Quite good idea to build a system captured for the. Available water and the vulnerable pressure and available parts. Really amazing effort to, to, to build, uh, to truly build a solar system for your own solution. Or maybe this other aspect is more important. the fact that they actually did it in a world full of regulations, you know?

[00:43:28] Wojciech Węgrzyński: Full of standards codes. Uh, insurers, I mean, this system would never be approved if they were not an administration. If they were not creating their own laws in their own country, being able to do whatever they like to do. And I feel that's a, that's a shame, maybe in many other places, we would be able to design systems that could just feel our need.

[00:43:52] Wojciech Węgrzyński: fill that and nothing more, nothing less, but we are. Limited by the system that surrounds us a system that of course provides a safety and [00:44:00] gives us some rules to play. I guess everyone in the game is. Uh, appreciates that or has to follow that what we've built. But sometimes now on projects like this, having this complete freedom.

[00:44:14] Wojciech Węgrzyński: To design the safety solution for your tunnel. This is brilliant. Brilliant. And now I know us as. You've mentioned, they are installing a very similar system in Poland. Actually, one of the manufacturers who participated in these tests with a Swedish show that administration is now offering this kind of a system with a single lodge pipe through the middle of a tunnel. Alyssa.

[00:44:36] Wojciech Węgrzyński: As a common solution. That's. That can be used in different tunnels. It's not the exactly same solution as far as I know. So, um, you have a chance to, to change the lengths of the sections. Uh, There are pumping stations to get the performance you want to achieve. It is a little bit codified now, not as free as it was in Sweden.

[00:44:57] Wojciech Węgrzyński: But still, it's an interesting advancement in, in [00:45:00] providing fire protection for tunnels. I must say a moderate cost and. Whenever the topic of sprinklers is brought up. In Poland, at least I don't know about your countries, but in Poland it's always mentioned, oh, this is gonna be so expensive. We cannot afford that. And, it seems you can, it seems, it seems if you're smart, if you're building your.

[00:45:19] Wojciech Węgrzyński: Systems in a way that, uh, one safety feature can compensate for other safety features that you can maybe lower a bit. You may eventually find money to, to buy them. I really like this way of thinking like this way of looking on safety. And I certainly appreciate how brave people like off can. And steal create and, design new solutions in, in 21st century when everything is rigid, tested, and qualified. So thank you Ulf for, for sharing your story with listeners of fire science show.

[00:45:52] Wojciech Węgrzyński: And this is the fireside show. Thank you very much for being here with me. And, uh, if you'd like to learn about my feelings [00:46:00] about the invasion in Ukraine and what happened in the here in the last year. You can join me on Friday where highly we'll publish additional QA episode about this. And if you're interested in more fire science,

[00:46:12] Wojciech Węgrzyński: There is a lot more fire science coming your way on next Wednesday. So thank you very much. See you. Bye.