040 - Resilient road tunnel infrastructure with Ingo Riess

WEBVTT

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<v Wojciech Wegrzynski>Hello, everybody.

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<v Wojciech Wegrzynski>Welcome to the fire science show episode 40.

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<v Wojciech Wegrzynski>It's kind of difficult to record this in the cheerful manner when.

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<v Wojciech Wegrzynski>There is a war next doors, like literally in the country.

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<v Wojciech Wegrzynski>Next to mine and.

00:00:14.516 --> 00:00:15.926
<v Wojciech Wegrzynski>we've been called paranoid.

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<v Wojciech Wegrzynski>About Russia.

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<v Wojciech Wegrzynski>We Polish people.

00:00:18.263 --> 00:00:20.405
<v Wojciech Wegrzynski>now you see what we were afraid of.

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<v Wojciech Wegrzynski>Anyway.

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<v Wojciech Wegrzynski>Let's hope for the best.

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<v Wojciech Wegrzynski>I can only tell you that the Polish nation is extremely supportive to the Ukrainians.

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<v Wojciech Wegrzynski>both in terms of supporting their military efforts.

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<v Wojciech Wegrzynski>And at the same time, supporting those who escape.

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<v Wojciech Wegrzynski>From Ukraine and the.

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<v Wojciech Wegrzynski>And this mainly women and children and.

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<v Wojciech Wegrzynski>I must tell you.

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<v Wojciech Wegrzynski>observation.

00:00:41.082 --> 00:00:42.372
<v Wojciech Wegrzynski>It's really surprised me.

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<v Wojciech Wegrzynski>There is hundreds of thousands of young ukrainian males who are working in Poland, who are on their way to the Ukraine to fight.

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<v Wojciech Wegrzynski>If that's not being a hero, then I don't know what is.

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<v Wojciech Wegrzynski>Anyway.

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<v Wojciech Wegrzynski>Let's not make the spotless political, let's go back to fire science and, I hope.

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<v Wojciech Wegrzynski>to some of you hardest to this will at least let you.

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<v Wojciech Wegrzynski>Escape the Realty for some brief time, Today I have a guest today when we wanted to invite to the podcast for a long time.

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<v Wojciech Wegrzynski>Dr Ingo Riess.

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<v Wojciech Wegrzynski>Ingo is an engineer working with our roads tunnels.

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<v Wojciech Wegrzynski>And tunnels in general.

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<v Wojciech Wegrzynski>And to me, he's one of the biggest authorities in terms of engineering tunnels he's not a researcher, but he surely acts like one.

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<v Wojciech Wegrzynski>I love that.

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<v Wojciech Wegrzynski>He's experienced with designing tunnels performing risk analysis.

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<v Wojciech Wegrzynski>One dimensional, um, ventilation analysis and just being a part Often efforts to design some of the Europe's biggest tunnels.

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<v Wojciech Wegrzynski>He's experienced this immense and I was looking forward to the talk because I'm myself, I'm a total engineer lately and we've been involved in many, many road tunnels in Poland.

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<v Wojciech Wegrzynski>So this episode was as much for me as for.

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<v Wojciech Wegrzynski>For you.

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<v Wojciech Wegrzynski>And I've truly learned a lot from that.

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<v Wojciech Wegrzynski>it's a good one.

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<v Wojciech Wegrzynski>You want to listen to, to the end?

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<v Wojciech Wegrzynski>So that's not prolong this anymore that's been the intro and jump into the episode Hello everybody.

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<v Wojciech Wegrzynski>I'm here today with Dr Ingo Riess from Riess Engineur GmbH..

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<v Wojciech Wegrzynski>Hello, Ingo and great to have you here.

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<v Ingo Riess>Hello.

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<v Ingo Riess>Thank you for having me.

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<v Wojciech Wegrzynski>I wanted this for a long time.

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<v Wojciech Wegrzynski>I mean, you're a fellow tunnel engineer, which is probably the closest part to my heart now in the fire engineering world.

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<v Wojciech Wegrzynski>And.

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<v Wojciech Wegrzynski>I must say the resources you provide in your papers and the repos that you participate are priceless to me.

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<v Wojciech Wegrzynski>So I loved the opportunity to talk to you, like face to face.

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<v Wojciech Wegrzynski>Thanks for coming.

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<v Ingo Riess>thank you.

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<v Wojciech Wegrzynski>Okay.

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<v Wojciech Wegrzynski>Recently I, uh, came a report that you've participated on the resiliency of tunnels that was done for PIARC And, I saw you doing a lot of work around the topic of resiliency of tunnels.

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<v Wojciech Wegrzynski>And actually I would love to start with that because that gives us a better impression of why we should design safety in tunnels and how to design it.

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<v Wojciech Wegrzynski>So maybe let's start with.

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<v Wojciech Wegrzynski>Defining what's resiliency in the world of tunnels

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<v Ingo Riess>that's a rather difficult question.

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<v Ingo Riess>We

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<v Wojciech Wegrzynski>know.

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<v Ingo Riess>I'm in a broken group of PIARC In the initial meetings, uh, we try to find a definition, a common definition of resilience, and this was really difficult and it had to be revised several times.

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<v Ingo Riess>For a for tunnels of for the traffic network it's about keeping traffic moving.

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<v Ingo Riess>And if there is a disturbance to the system to get back online as quickly as possible.

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<v Ingo Riess>So the resilience is the measure of, the possibility of keep the network or the connect traffic connection open from any adverse impact.

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<v Ingo Riess>And if there's, the connection is broken to get it open as fast as possible.

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<v Wojciech Wegrzynski>Like the ability to restart, doing normal operation.

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<v Wojciech Wegrzynski>As quickly and as little cost as possible.

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<v Wojciech Wegrzynski>Right.

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<v Ingo Riess>and there's always the aspect of safety.

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<v Ingo Riess>If the tunnel is broken, you can always open it.

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<v Ingo Riess>If you accept any level of safety or unsafety.

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<v Wojciech Wegrzynski>I like the goal of the tunnels to get the traffic moving.

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<v Wojciech Wegrzynski>And, yeah, we, we build them now in Poland.

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<v Wojciech Wegrzynski>For example, Poland is not a very mountainous country.

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<v Wojciech Wegrzynski>We have mountains in the south of Poland, but it's not a part of huge, conurbations or something.

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<v Wojciech Wegrzynski>We have their connections with our neighbors, but now I'm mostly involved or are highly involved in tunnels being built in cities, in large cities as a part of like giving the city back to the citizens.

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<v Wojciech Wegrzynski>And that's a trend that's been here for ages.

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<v Wojciech Wegrzynski>If I.

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<v Wojciech Wegrzynski>remember correctly, there was this huge, fire safety program, Memorial tunnel, and that was connected to a large project like that.

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<v Wojciech Wegrzynski>I think it was in Boston, the USA, where they tried to move, uh,

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<v Ingo Riess>Central.

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<v Wojciech Wegrzynski>Yeah.

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<v Wojciech Wegrzynski>And, that was like 30 or 40 years ago.

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<v Wojciech Wegrzynski>And the trend is now in here.

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<v Wojciech Wegrzynski>And we start digging under the cities.

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<v Wojciech Wegrzynski>We start building this huge tunnels for large volumes of vehicles.

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<v Wojciech Wegrzynski>And this approach is not going anywhere because it seems to be, a successful and w with this growing demand for tunnels growing, Traffic volumes in this tunnels and the modern view on, safety, which is unfortunately triggered by huge tunnel fires we've had in the past.

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<v Wojciech Wegrzynski>This project seemed to be increasingly challenging, at least for us in here, like the expectations are higher and higher.

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<v Wojciech Wegrzynski>Not necessarily saying that the targets are higher because the target was always for the tunnel to be safe, but the solutions to provide that safety are increasing.

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<v Wojciech Wegrzynski>Is that something you observe as well in you're designing tunnels for quite a while, I guess.

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<v Ingo Riess>and my impression is that there's, it's a pendulum.

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<v Ingo Riess>So after the, the large tunnel fires we had.

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<v Ingo Riess>Demand for safety.

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<v Ingo Riess>And, the government put up a lot of money to increase, tunnel safety.

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<v Ingo Riess>And right now it's swinging back a little bit.

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<v Ingo Riess>in, in central Europe, we've got these design codes, so everything is pretty much defined and it wouldn't decrease much above that.

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<v Ingo Riess>On the other hand, there are tendencies to.

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<v Ingo Riess>Except the higher level of risk, for reduced cost.

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<v Ingo Riess>So at the moment, it's more like, possibly going away from these prescriptive codes to risk analysis.

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<v Ingo Riess>And in that way to accept more risk for particular tunnels or infrastructure or.

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<v Wojciech Wegrzynski>But the thing you can really compensate that in the risk.

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<v Wojciech Wegrzynski>The bottom line is that if you allow for heavy vehicle traffic in the tunnel, any heavy vehicle traffic, you will eventually have a scenario.

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<v Wojciech Wegrzynski>There is a large fire in the tunnel, like very large fire.

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<v Wojciech Wegrzynski>Even like for me, cutting probability by half or one-third, it doesn't really make such a big difference because still you have this scenario.

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<v Wojciech Wegrzynski>I know it may go from like a 10 to the minus five to the 10 to the minus of six, but, is this a big enough change in probability or risk that to, to allow significant cost reductions

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<v Ingo Riess>the argument in Switzerland is that, you could save money in your tunnel and you could spend it elsewhere for road safety.

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<v Wojciech Wegrzynski>uh,

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<v Ingo Riess>So the tunnels are inherently more safe than the open road in average.

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<v Ingo Riess>So accepting more risk in a tunnel,  set, gives you additional.

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<v Ingo Riess>to solve accident points risky points on the open road network.

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<v Ingo Riess>That's the argument and the truck fire or the dangerous goods fire in a tunnel.

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<v Ingo Riess>You have to weigh it against a dangerous goods event on the open road.

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<v Ingo Riess>So we have this discussion again in another country, another project where we discuss dangerous goods in the.

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<v Ingo Riess>And then the argument was what happens if the accident is not in the tunnel, but in the residential area above ground.

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<v Ingo Riess>So in the end, it always should be about risk, but the problem with risk is then you are in performance-based design.

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<v Ingo Riess>And then it's a question.

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<v Ingo Riess>How do you prove that you meet the requirements and how do you prove that you are on the safe.

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<v Wojciech Wegrzynski>I like the two cases that you've made.

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<v Wojciech Wegrzynski>One is that the whole road system is a, is one body.

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<v Wojciech Wegrzynski>And the, you can holistically approach it, especially that in most countries, I would say.

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<v Wojciech Wegrzynski>there is some governmental authority that manages all of it.

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<v Wojciech Wegrzynski>It's not like a bunch of private tunnels of combating gas companies.

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<v Wojciech Wegrzynski>It's, it's mostly, uh, uh, one network in the country.

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<v Wojciech Wegrzynski>And if in fact, you do, free funds in one project to improve safety in another project.

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<v Wojciech Wegrzynski>That's fantastic.

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<v Wojciech Wegrzynski>And the second thing you've mentioned about the, fire or the catastrophic event happening.

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<v Wojciech Wegrzynski>If there was just the road, not the tunnel and you're right.

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<v Wojciech Wegrzynski>It's a, from my experience also is it's usually would be worse than in a tunnel, at least for the people around that, location.

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<v Wojciech Wegrzynski>And this is a very difficult thing to convey to the, communities that needed tunnels.

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<v Ingo Riess>Yeah.

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<v Ingo Riess>It's well, it's the European approach that the whole network is operated by the government, but there are numerous countries where especially tunnels are built and operated by private.

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<v Ingo Riess>We'd have contracts with the road network operator.

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<v Ingo Riess>And this makes the concept of resilience rather complicated because the operator looks at his object is a piece of infrastructure he's tunnel or bridge or whatever.

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<v Ingo Riess>And he wants his, piece of road of the road network as resilient as possible.

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<v Ingo Riess>While the network operator may not be in.

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<v Ingo Riess>In that resilience, especially for an urban town.

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<v Ingo Riess>When you, you mentioned the urban tunnels in Poland, when you have the urban road network around that, if the tunnel has closed, the traffic capacity will be drastically reduced, but the connection will not be closed.

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<v Ingo Riess>So it's not such a big issue as for a tunnel like Mount Blanc, or that's really connecting.

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<v Ingo Riess>and would require a detour of hundred kilometers.

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<v Ingo Riess>it's a different perspective.

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<v Ingo Riess>Are your network operator, are you a tunnel operator or are you the driver just wanting to get from.

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<v Wojciech Wegrzynski>And.

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<v Wojciech Wegrzynski>From your experience for this, private projects is this, capacity to, to restart the tunnel, this resiliency.

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<v Wojciech Wegrzynski>Reflected in the design, because, for us, as you mentioned in European, we have standardization and codes and the good practices that we usually follow.

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<v Wojciech Wegrzynski>And we're usually limited to that.

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<v Wojciech Wegrzynski>So is this resiliency, a design factor that you would design for you?

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<v Wojciech Wegrzynski>Would you spend more money on the tunnel systems, to improve that?

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<v Wojciech Wegrzynski>Which like install, uh, I know sprinklers in the tunnel just for this.

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<v Ingo Riess>Resilience is a rather new concept when it comes to tunnels or Road networks.

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<v Ingo Riess>Let's, let's stick to road networks, it's a new concept.

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<v Ingo Riess>And so far, I think there aren't too many examples where really improvements have been made for resilience.

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<v Ingo Riess>but, the effects are already noticed in, 2016 and 2017, there were rather similar fires in a road tunnel in Germany and in the road tunnel in Austria.

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<v Ingo Riess>And the German tunnel was equipped with a foam fire suppression system.

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<v Ingo Riess>The Austrian tunnel was not.

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<v Ingo Riess>So the Austrian tunnel had a fully developed fire and the tunnel was closed for, I think just about two months.

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<v Ingo Riess>And the German tunnel was closed for about seven or eight hours.

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<v Ingo Riess>So that's resilience, but then you have to consider how much money is the other two months worth.

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<v Ingo Riess>is it reasonable to install such a system to maintain it and test it and operate it?

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<v Ingo Riess>Just to get these two months of operation every 20 years and lots of discussion.

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<v Ingo Riess>Only starting right now.

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<v Ingo Riess>I think that's, in most existing tunnels, this has not been investigated.

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<v Wojciech Wegrzynski>for us, this is in a way problematic because in our law system, which is very prescriptive, like it gives you this.

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<v Wojciech Wegrzynski>Certain requirements.

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<v Wojciech Wegrzynski>You'd your total must pass to be allowed to be built.

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<v Wojciech Wegrzynski>There is almost no ways to include, benefits from like extinguishing systems.

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<v Wojciech Wegrzynski>You, you cannot.

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<v Wojciech Wegrzynski>Install a system and decrease the fire resistance.

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<v Wojciech Wegrzynski>If your walls or don't do a spalling protection on your walls, you cannot lower the capacity of your exhaust system.

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<v Wojciech Wegrzynski>You cannot change the design fire scenario.

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<v Wojciech Wegrzynski>Maybe you can, but it takes a lot of efforts to do that.

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<v Wojciech Wegrzynski>So you are not required to install it and you want to install it.

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<v Wojciech Wegrzynski>You know, the benefits are there, but it's difficult for you to benefit your design that would allow you to, loosen some other requirements.

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<v Ingo Riess>I don't necessarily agree with that.

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<v Ingo Riess>As an example in Switzerland, we currently design.

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<v Ingo Riess>Started to construct the second tube of the Gotthard road tunnel.

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<v Ingo Riess>And this is in principle, a resilience measure because it increases the safety because we've got uni director and the traffic in both tunnels in the end.

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<v Ingo Riess>But first we have to close the existing road tunnel for a couple of years, month.

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<v Ingo Riess>And there has been a study made on  what to do, uh, while the tunnel is refurbished.

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<v Ingo Riess>And, there were several options investigated, like, temporarily using the old rail tunnel, like using the detour across some Bernardino, which would mean several hundred kilometers of detour.

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<v Ingo Riess>and the study calculated the societal.

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<v Ingo Riess>So it was not investment against investment, but costs societal costs, including environmental impact, including, increasing accidents on the open roads.

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<v Ingo Riess>so all of this was investigated and in the end, the government decided, well it's well worth building a second cube to increase safety and, to reduce the impact of the tunnel closure.

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<v Ingo Riess>So this was a cost benefit analysis covering the 30 years, 50 years of tunnel operation.

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<v Ingo Riess>And the government decided, that it's worth including these societal costs, that's public money.

00:14:57.225 --> 00:14:58.095
<v Ingo Riess>That's private money.

00:14:58.475 --> 00:14:59.384
<v Ingo Riess>It's not money.

00:14:59.384 --> 00:15:01.184
<v Ingo Riess>The government saves directly.

00:15:01.778 --> 00:15:12.288
<v Ingo Riess>So if, if you have a more global view on your infrastructure, it may be well-worth for the government as a road network operator to increase resilience.

00:15:12.711 --> 00:15:16.792
<v Wojciech Wegrzynski>I think it's a discussion we need to open in Poland with our road operator.

00:15:16.831 --> 00:15:20.601
<v Wojciech Wegrzynski>They seem to be open for discussions in fields like that.

00:15:20.601 --> 00:15:25.402
<v Wojciech Wegrzynski>And I think the points are very strong that you have to look beyond.

00:15:26.047 --> 00:15:29.600
<v Wojciech Wegrzynski>Just a, the most basic costs of your system.

00:15:29.600 --> 00:15:30.379
<v Wojciech Wegrzynski>And that is it.

00:15:30.679 --> 00:15:47.528
<v Wojciech Wegrzynski>We wouldn't have not even mentioned life safety yet in this discussion because it's self-evident that if you install sprinkler system or some other technical means you will also improve the life safety and operational capacities of the fire brigade, at the same time.

00:15:47.528 --> 00:15:50.077
<v Wojciech Wegrzynski>But this is something that is, is fundamental.

00:15:50.102 --> 00:15:53.643
<v Ingo Riess>it's, it's a standardized approach in Switzerland.

00:15:53.673 --> 00:16:06.836
<v Ingo Riess>You have to do this type of it's a defined procedure, this cost benefit analysis, and you have to do it for every project, every new tunnel, every refurbishment project, and the Gotthard is not the only example.

00:16:06.836 --> 00:16:09.356
<v Ingo Riess>There's the Belchen tunnel, which is.

00:16:10.407 --> 00:16:18.870
<v Ingo Riess>Along on one of the main traffic arteries in Switzerland, which is now getting a third tube for the refurbishment of the existing two ones.

00:16:19.139 --> 00:16:22.019
<v Ingo Riess>And there will never be all three cubes open to traffic.

00:16:22.289 --> 00:16:26.250
<v Ingo Riess>It's just a temporary measure for the refurbishment to have another tunnel tube.

00:16:26.907 --> 00:16:31.840
<v Ingo Riess>And it's, the cost benefit analysis shows it's worth to do that.

00:16:31.840 --> 00:16:33.879
<v Ingo Riess>It's better than closing the tunnel for a couple of.

00:16:34.977 --> 00:16:36.331
<v Wojciech Wegrzynski>That is astonishing.

00:16:36.746 --> 00:16:38.336
<v Ingo Riess>it's really the question.

00:16:38.442 --> 00:16:43.432
<v Ingo Riess>how do you value the time spent for the, the driver needs on a detour?

00:16:44.153 --> 00:16:45.472
<v Ingo Riess>How do you deviate the traffic?

00:16:45.472 --> 00:16:46.643
<v Ingo Riess>What's the impact there?

00:16:47.003 --> 00:16:48.773
<v Ingo Riess>And in the end, the cost benefit is.

00:16:49.398 --> 00:16:50.288
<v Wojciech Wegrzynski>that is astonishing.

00:16:50.347 --> 00:17:00.904
<v Wojciech Wegrzynski>I wanted to drive the discussion towards refurbishment because, I also know that in the Western Europe, like in Germany, or I assume in Austria and Switzerland as well.

00:17:01.044 --> 00:17:03.485
<v Wojciech Wegrzynski>The tunnel network is actually quite old.

00:17:03.815 --> 00:17:08.758
<v Wojciech Wegrzynski>You guys have been digging these things for, hundreds of years almost.

00:17:08.938 --> 00:17:13.698
<v Wojciech Wegrzynski>I think the, the median age of a railway tunnel in Germany is above hundred.

00:17:14.087 --> 00:17:15.576
<v Wojciech Wegrzynski>So that's quite a challenge.

00:17:16.027 --> 00:17:16.807
<v Wojciech Wegrzynski>I wonder.

00:17:16.882 --> 00:17:30.991
<v Wojciech Wegrzynski>How you approach, like you've mentioned now that the third tube, which is for me exotic and amazing concept to, to build for resiliency, but how you approach like developing safety and resiliency.

00:17:30.991 --> 00:17:36.372
<v Wojciech Wegrzynski>When you get into a tunnel that's a hundred years old and you have to work with what you have there.

00:17:36.593 --> 00:17:39.839
<v Ingo Riess>There's no general approach at first, you have to that's.

00:17:40.079 --> 00:17:42.420
<v Ingo Riess>These are the most interesting projects for the design.

00:17:42.420 --> 00:17:48.210
<v Ingo Riess>Of course, first you have to see what is what's there and what can you do with it?

00:17:48.210 --> 00:17:54.680
<v Ingo Riess>And is it possible to upgrade it to current standards or do you have to deviate from that because of the stuff you have.

00:17:55.951 --> 00:18:05.508
<v Ingo Riess>we have ventilation systems conversion from transverse fully transfers concept to longitudinal concept or longetudinally with local smoke extraction.

00:18:06.347 --> 00:18:09.317
<v Ingo Riess>Then you get different pressure forces on the false ceilings.

00:18:09.317 --> 00:18:17.384
<v Ingo Riess>So do you have to strengthen the false ceiling or do you have to reduce the flow rates or do you have to change the concept?

00:18:18.277 --> 00:18:21.997
<v Ingo Riess>Change your fans from fixed blade to variable pitch.

00:18:23.196 --> 00:18:27.037
<v Ingo Riess>There are so many options what you can do, but you have to analyze each project.

00:18:27.441 --> 00:18:30.799
<v Wojciech Wegrzynski>this intriguing guy you've said transversal into longitudinal

00:18:31.165 --> 00:18:36.950
<v Ingo Riess>there are a couple of tunnels where we remove the false ceiling and use the full cross-section for longitudinal ventilation.

00:18:37.579 --> 00:18:38.599
<v Ingo Riess>When it's unidirectional.

00:18:39.317 --> 00:18:51.287
<v Ingo Riess>there are projects where part of the full ceiling has been removed to make room for jet fans and other parts are sturdy used as a cable tunnel or cable duct.

00:18:51.930 --> 00:18:55.259
<v Ingo Riess>it's the kind of work where you as a designer can become really.

00:18:55.980 --> 00:18:58.880
<v Wojciech Wegrzynski>I'm asking that because in here we have.

00:18:58.936 --> 00:19:06.686
<v Wojciech Wegrzynski>this assumption, and I'm not sure where it came from that transversal system is, universally better than longitudinal system.

00:19:07.257 --> 00:19:11.410
<v Wojciech Wegrzynski>And, I have worked with transpersonal systems and, I'm not necessarily.

00:19:12.045 --> 00:19:20.394
<v Wojciech Wegrzynski>Convinced that is the case probably when you have by direction, a little tunnel, that's the only way you can go,  to have, safe conditions, both sides.

00:19:20.845 --> 00:19:26.974
<v Wojciech Wegrzynski>But if the traffic is unidirectional, it really don't feel that improvement.

00:19:27.234 --> 00:19:27.825
<v Ingo Riess>transversal.

00:19:28.164 --> 00:19:31.494
<v Ingo Riess>I mean, distributed, fresh air and distributed exhaust there.

00:19:31.825 --> 00:19:40.105
<v Ingo Riess>I mean, we've got the, we've got the local smoke extraction with the dampers and this is still, this is used in new tunnels in new bi-directional towns.

00:19:40.105 --> 00:19:40.464
<v Ingo Riess>Have a certain.

00:19:41.384 --> 00:19:48.352
<v Ingo Riess>but, uh, we found after the large fires in Europe, that the distributed exhausts doesn't really work.

00:19:48.660 --> 00:19:50.488
<v Ingo Riess>you have to have local extraction in half.

00:19:50.637 --> 00:19:55.817
<v Ingo Riess>You have to have airflow control in the tunnel using jet fans to control the flow velocity.

00:19:56.222 --> 00:19:56.583
<v Wojciech Wegrzynski>yeah.

00:19:56.845 --> 00:20:00.234
<v Ingo Riess>and this control algorithms are still challenging.

00:20:00.450 --> 00:20:00.960
<v Wojciech Wegrzynski>I know

00:20:02.285 --> 00:20:06.148
<v Ingo Riess>They asked that used in Switzerland, in Austria for a long time now.

00:20:06.179 --> 00:20:12.692
<v Ingo Riess>And they work pretty well, but still the requirements, in my opinion, the requirements are not Very well-defined.

00:20:13.345 --> 00:20:14.755
<v Ingo Riess>We know where we want to go.

00:20:14.994 --> 00:20:18.862
<v Ingo Riess>We want to have symmetric flow or we want to have a reduced flow velocity.

00:20:18.862 --> 00:20:22.192
<v Ingo Riess>If there's no smoke extraction, we don't go for critical analysis.

00:20:23.106 --> 00:20:23.557
<v Wojciech Wegrzynski>I love you.

00:20:24.731 --> 00:20:29.051
<v Ingo Riess>But it's, currently these control algorithms are defined as you have.

00:20:29.261 --> 00:20:44.299
<v Ingo Riess>You have to get to that target and you have to get there within say five minutes after fire detecion But I think that that's not enough because sometimes it's better to approach to do it slowly and not use all the jet fans in the tunnel.

00:20:44.480 --> 00:20:52.993
<v Ingo Riess>And today there are jet fans of their tunnels where when the tires detected all the jet fans thought, and these designers, I think, forgot that.

00:20:53.461 --> 00:21:00.670
<v Ingo Riess>The reason why you want to achieve that target of maybe 1.5 meter per second, you want to maintain smoke stratification.

00:21:01.660 --> 00:21:06.490
<v Ingo Riess>And if you spin on all the jet fans in the tunnel, you don't have any smoke stratification.

00:21:07.353 --> 00:21:09.634
<v Ingo Riess>So the measure defeats the objective

00:21:10.304 --> 00:21:10.859
<v Wojciech Wegrzynski>Exactly.

00:21:11.250 --> 00:21:15.569
<v Wojciech Wegrzynski>I love how you segwayed me into the next question I wanted to ask you.

00:21:15.960 --> 00:21:29.926
<v Wojciech Wegrzynski>You you've mentioned symmetric, conditions at ends of the smoke controls, zone and, some assumptions behind the flow management, like starting all the jet-fans at the same, or, or controlling that in a better way.

00:21:30.950 --> 00:21:40.324
<v Wojciech Wegrzynski>A lot of that comes to this unrealistic assumptions or ideas that we go when we modeled tunnels.

00:21:40.957 --> 00:21:47.182
<v Wojciech Wegrzynski>if you, Go into, um, project with the download and you simulate it or you check out the simulations.

00:21:47.648 --> 00:21:53.515
<v Wojciech Wegrzynski>the there's usually no traffic because it's, it's a hell of a problem to model traffic along CFD.

00:21:53.815 --> 00:21:57.432
<v Wojciech Wegrzynski>Or even if you did, it's, not really reliable because.

00:21:57.835 --> 00:22:02.049
<v Wojciech Wegrzynski>Small change in traffic will result in large change in the simulation outcomes.

00:22:02.049 --> 00:22:07.130
<v Wojciech Wegrzynski>So you would have to run a, some Monte Carlo probably to get it right, and that you cannot afford that.

00:22:07.869 --> 00:22:15.866
<v Wojciech Wegrzynski>you usually start with the initial conditions like zero, uh, zero velocity and no movement static field.

00:22:16.176 --> 00:22:23.029
<v Wojciech Wegrzynski>Then you start your fire, which is a beautiful, buoynt plume that touches your ceiling flows both directions.

00:22:23.579 --> 00:22:26.809
<v Wojciech Wegrzynski>Then you start your fans and they disturb it.

00:22:27.440 --> 00:22:37.200
<v Wojciech Wegrzynski>You don't usually consider metrology like the weather conditions outside and not even touch the mistakes people doing the simulations with the grid size or.

00:22:37.779 --> 00:22:49.886
<v Wojciech Wegrzynski>Or a bunch of conditions but this initial image is so different than what you would see in a tunnel where you're in one  we have a tunnel with it, with a bus stop in the middle of it in Warsaw.

00:22:49.886 --> 00:22:53.846
<v Wojciech Wegrzynski>So if you go there, there is definitely a movement in there.

00:22:54.237 --> 00:22:58.346
<v Wojciech Wegrzynski>Uh, not to mention that noise is unbearable but the air movement is always there.

00:22:58.346 --> 00:23:02.250
<v Wojciech Wegrzynski>And, it doesn't like magically disappear when you have a fire.

00:23:02.640 --> 00:23:07.775
<v Wojciech Wegrzynski>So your initial field yes, it's already, you need directional air movement.

00:23:07.775 --> 00:23:10.744
<v Wojciech Wegrzynski>That will make a lot of funny things to the smoke.

00:23:11.015 --> 00:23:21.521
<v Wojciech Wegrzynski>And I'm doing this simulations and I'm doing it like everyone is doing because otherwise I would not be able to explain to the stakeholders why I'd done it differently in why it's better.

00:23:22.162 --> 00:23:23.511
<v Wojciech Wegrzynski>Maybe I should try one day.

00:23:23.571 --> 00:23:24.051
<v Wojciech Wegrzynski>We'll see.

00:23:24.386 --> 00:23:37.497
<v Wojciech Wegrzynski>I think it did go well, but you know, there is something with this that we, we put so much focus into super detailed analysis where the initial conditions are just plain wrong and I feel I'm doing it wrong.

00:23:37.856 --> 00:23:38.967
<v Wojciech Wegrzynski>Are you doing it wrong as well?

00:23:39.727 --> 00:23:44.586
<v Ingo Riess>I think I never had to do a CFD design safety of a simulations for a tunnel design.

00:23:45.096 --> 00:23:45.547
<v Wojciech Wegrzynski>Really?

00:23:46.250 --> 00:23:54.740
<v Ingo Riess>I think for a few projects, we had to deliver it, but this was more about jet fan debt, impingement on traffic and things like that.

00:23:54.800 --> 00:23:57.111
<v Ingo Riess>But I didn't never did a fire simulation.

00:23:57.171 --> 00:23:58.580
<v Ingo Riess>I always avoided that.

00:23:59.181 --> 00:24:03.586
<v Ingo Riess>And today when I'm working on a project, I have someone else do it.

00:24:03.886 --> 00:24:05.326
<v Ingo Riess>I'm not really interested in this.

00:24:06.017 --> 00:24:10.030
<v Ingo Riess>When I see the fire life safety report for these performance based design.

00:24:10.710 --> 00:24:20.806
<v Ingo Riess>Project, they do it, as you say, they use FDS and they use standard boundary conditions, still air as an initial condition, no traffic movement.

00:24:22.125 --> 00:24:29.528
<v Ingo Riess>And they have an egress model showing that everyone gets to the nearest door And well, you have the two scenarios.

00:24:29.528 --> 00:24:33.338
<v Ingo Riess>You have the unidirectional traffic, which is boring because the result is always.

00:24:34.131 --> 00:24:37.371
<v Ingo Riess>And you have the bi-directional tunnel where things get really messy.

00:24:39.425 --> 00:24:42.365
<v Wojciech Wegrzynski>and reasonably is always complicated.

00:24:42.560 --> 00:24:49.903
<v Ingo Riess>what I would like to do at least in the initial, I mean, it's, it's really, a scientific level of CFD.

00:24:49.903 --> 00:24:59.530
<v Ingo Riess>If you start with moving vehicles and moving boundary conditions and dynamic flow conditions, that's not standard stuff you would expect in a design.

00:25:00.243 --> 00:25:10.259
<v Ingo Riess>But what you can do is you can combine the findings from this kind of steady state CFT, 3d modeling with a dynamic 1-D model.

00:25:10.872 --> 00:25:17.682
<v Ingo Riess>So you combine how realistic you can prove show how realistic or unreal realistic are the boundary conditions.

00:25:17.726 --> 00:25:21.378
<v Ingo Riess>And then you have to make an interpretation, which is.

00:25:21.709 --> 00:25:25.727
<v Ingo Riess>Difficult for the client because he wants to see the numbers and the pictures.

00:25:25.757 --> 00:25:26.987
<v Ingo Riess>What does the smoke do?

00:25:27.567 --> 00:25:29.490
<v Ingo Riess>But I think that would be the right way to.

00:25:30.320 --> 00:25:32.540
<v Wojciech Wegrzynski>You think that in this field?

00:25:33.113 --> 00:25:36.816
<v Wojciech Wegrzynski>1-D modeling or the traffic, sorry.

00:25:36.855 --> 00:25:49.026
<v Wojciech Wegrzynski>The network, a modeling of tunnels would be a superior to CFD because of this capacity to model multiple scenarios versus a nice three dimensional flow field in a, in a

00:25:49.651 --> 00:25:57.560
<v Ingo Riess>the thing about 1D is when I do a tunnel model and simulate a fire, I have about seven seconds simulation.

00:25:58.049 --> 00:25:58.961
<v Ingo Riess>For a scenario.

00:25:59.976 --> 00:26:00.215
<v Wojciech Wegrzynski>that's

00:26:00.250 --> 00:26:06.441
<v Ingo Riess>So there are quite a lot of scenarios I can look at and find the critical ones and understand how the system works.

00:26:06.441 --> 00:26:11.292
<v Ingo Riess>If it's a steep gradient tunnel that the behavior will show me a pattern.

00:26:11.713 --> 00:26:24.007
<v Ingo Riess>And if I interpret this pattern, right, I can develop the optimized ventilation solution A single CFD simulation 3d will not help me to see.

00:26:25.167 --> 00:26:26.491
<v Wojciech Wegrzynski>that's really that's powerful.

00:26:26.491 --> 00:26:29.692
<v Wojciech Wegrzynski>I, our experience is, opposite.

00:26:29.721 --> 00:26:34.046
<v Wojciech Wegrzynski>We would, do CFD for this projects.

00:26:34.624 --> 00:26:39.064
<v Wojciech Wegrzynski>Mainly, well, we're usually having jet fans and stuff like that.

00:26:39.064 --> 00:26:43.410
<v Wojciech Wegrzynski>And you would like to see is the placement of jet fence, correct?

00:26:43.487 --> 00:26:45.287
<v Wojciech Wegrzynski>did they interfere with each other?

00:26:45.737 --> 00:26:54.903
<v Wojciech Wegrzynski>But frankly, the reality is the main goal is, is to present the authorities with, proof of compliance that, the conditions are maintained for like seven minutes.

00:26:54.913 --> 00:26:55.953
<v Wojciech Wegrzynski>And they're good.

00:26:56.554 --> 00:26:57.153
<v Wojciech Wegrzynski>And.

00:26:57.163 --> 00:27:00.307
<v Wojciech Wegrzynski>From this perspective, the CFDs is necessary as.

00:27:00.977 --> 00:27:07.977
<v Wojciech Wegrzynski>We as engineers, we benefit from it partially by investigating some of the aspects.

00:27:07.977 --> 00:27:11.826
<v Wojciech Wegrzynski>But as you said, it's not possible to, it's not realistic.

00:27:11.826 --> 00:27:12.817
<v Wojciech Wegrzynski>I mean, it is possible.

00:27:12.817 --> 00:27:19.686
<v Wojciech Wegrzynski>It's just not realistic or economically viable to do, to run into this complex simulations.

00:27:19.686 --> 00:27:23.830
<v Wojciech Wegrzynski>So with, multiple variables in, in included in them and.

00:27:24.112 --> 00:27:30.682
<v Wojciech Wegrzynski>In that case, this is 1-D modeling or network modeling seems like an interesting approach.

00:27:31.011 --> 00:27:35.362
<v Wojciech Wegrzynski>We also deal with some very complex tunnel system.

00:27:36.207 --> 00:27:42.517
<v Wojciech Wegrzynski>That have junctions connections, multiple levels, not necessarily in road tunnels.

00:27:42.686 --> 00:27:43.436
<v Wojciech Wegrzynski>In road tunnels.

00:27:43.507 --> 00:27:59.017
<v Wojciech Wegrzynski>The world is a little simpler, but in railway tunnels, when you have a rail network with stations and stations have multiple levels, we felt that CFD was the only way we could truly track where the air will go once it enters the station.

00:27:59.047 --> 00:28:01.146
<v Wojciech Wegrzynski>If it has seven possible outlets.

00:28:01.311 --> 00:28:09.652
<v Ingo Riess>I mean the state railway station, an underground railway station is a classic example where you need CFD that's not one dimensional.

00:28:09.832 --> 00:28:11.182
<v Ingo Riess>That's highly three-dimensional.

00:28:11.651 --> 00:28:12.191
<v Wojciech Wegrzynski>exactly.

00:28:12.616 --> 00:28:16.855
<v Wojciech Wegrzynski>so you would also have these experiences switching from tool to tool in this manner.

00:28:17.153 --> 00:28:20.563
<v Ingo Riess>well, I, I've done very little CFD in my, Past work.

00:28:21.678 --> 00:28:21.978
<v Wojciech Wegrzynski>Uh,

00:28:22.182 --> 00:28:24.643
<v Ingo Riess>it's usually, uh, we have specialists for that.

00:28:24.836 --> 00:28:28.623
<v Ingo Riess>I don't do it myself, but I can, set the, define the boundary conditions.

00:28:28.623 --> 00:28:30.153
<v Ingo Riess>I can discuss the results.

00:28:30.242 --> 00:28:34.900
<v Ingo Riess>I can understand the flow, the mechanics of the software, I leave that to.

00:28:35.734 --> 00:28:47.404
<v Wojciech Wegrzynski>I actually highly respect that because I think this approach should be more widespread in the world and we would have much less issues with the systems as we do today.

00:28:47.944 --> 00:28:53.664
<v Wojciech Wegrzynski>I wanted to ask for another, interesting feedback loop that it's obvious, but it's in the way missing.

00:28:54.315 --> 00:29:01.964
<v Wojciech Wegrzynski>Impact of the airflow velocity and the growth of a fire or in general, our design fire assumptions for tunnels.

00:29:02.460 --> 00:29:09.779
<v Wojciech Wegrzynski>we've as a humanity, we've been lucky enough to have some full-scale controlled tunnel fire experiments.

00:29:09.779 --> 00:29:19.230
<v Wojciech Wegrzynski>Like the Memorial tunnel that has been mentioned, the Eureka Upton, there was Runehammar a fire tests that, or that was the part of Eureka.

00:29:19.319 --> 00:29:21.000
<v Wojciech Wegrzynski>I always confuse them.

00:29:21.069 --> 00:29:22.410
<v Ingo Riess>I think that was part of Eureka

00:29:22.675 --> 00:29:27.675
<v Wojciech Wegrzynski>there, there was the Metro project in Sweden, probably many more, fire experiments in the tunnels.

00:29:27.915 --> 00:29:33.730
<v Wojciech Wegrzynski>There's a tunnel testing facility in, in Spain, in Applus I think it's called the laboratory.

00:29:34.130 --> 00:29:42.633
<v Wojciech Wegrzynski>so we, we have this data points, and they show you the causes of, large vehicle fires and we just go and employ them in.

00:29:43.113 --> 00:29:54.395
<v Wojciech Wegrzynski>Design, but now when you think about fires in tunnels, there are factors that will for sure change the way, how the fire goes first, being the velocity of the air.

00:29:54.816 --> 00:29:56.346
<v Wojciech Wegrzynski>So you may have.

00:29:56.564 --> 00:30:11.208
<v Wojciech Wegrzynski>Something near the critical velocity where you just push the smoke, but not necessarily grow the fire, but if you blow 10 meters per second on the fire, I mean, you don't have to be a fire engineer to understand that increases the severity of the fire and the same with.

00:30:11.688 --> 00:30:16.317
<v Wojciech Wegrzynski>cross section of the tunnel, the, the hammer was like 47 square meters in cross section.

00:30:16.317 --> 00:30:18.807
<v Wojciech Wegrzynski>There was a tiny tunnel and the huge fire in it.

00:30:18.807 --> 00:30:26.335
<v Wojciech Wegrzynski>So the radiation from the walls is completely different than you would have, in the tunnel that was drilled with 12 meter diameter TBM machine.

00:30:26.827 --> 00:30:29.984
<v Wojciech Wegrzynski>so I wonder to what extent.

00:30:30.684 --> 00:30:37.887
<v Wojciech Wegrzynski>It makes sense to use these design fires as the ultimate basis for our design and other in other way.

00:30:37.887 --> 00:30:40.107
<v Wojciech Wegrzynski>I don't think we have another choice though.

00:30:40.878 --> 00:30:45.919
<v Ingo Riess>I didn't look too much into that because the fire dynamics, that's not really my field of expertise.

00:30:46.148 --> 00:30:52.568
<v Ingo Riess>an interesting, interesting aspect was brought up in the paper in Gratz in 2020, the.

00:30:53.086 --> 00:31:06.036
<v Ingo Riess>Geometry of the fire, is it usually we assume it's a point, a mathematical point in the tunnel but if it's a rail wagon on fire or a rail train, which really, if you have the large fires, it can't be a point.

00:31:06.036 --> 00:31:11.526
<v Ingo Riess>It must have some longitudinal extension and the physics change.

00:31:11.556 --> 00:31:17.313
<v Ingo Riess>If your fire is five meter long, or if it's 50 meters long and the critical velocity will change.

00:31:18.113 --> 00:31:22.603
<v Ingo Riess>the smoke spreading will change the oxygen supply towards the fire will change.

00:31:23.150 --> 00:31:26.269
<v Ingo Riess>I don't think this has been investigated in any depth.

00:31:27.074 --> 00:31:27.954
<v Wojciech Wegrzynski>the, the fire is also.

00:31:28.577 --> 00:31:29.508
<v Wojciech Wegrzynski>It pumps air.

00:31:29.537 --> 00:31:34.161
<v Wojciech Wegrzynski>If you take cold air you heat it up, you pump it upward and it goes away.

00:31:34.580 --> 00:31:39.270
<v Wojciech Wegrzynski>So it needs a lot of air for a hundred megawatts fire.

00:31:39.631 --> 00:31:47.070
<v Wojciech Wegrzynski>And if you do a CFD, you can see a local velocities of like five, 10 meters per second near the fire, just because the fire exists.

00:31:47.070 --> 00:31:48.810
<v Wojciech Wegrzynski>And it's so, so powerful in there.

00:31:49.260 --> 00:31:55.506
<v Wojciech Wegrzynski>And,  I don't think we take this into account, you know, that that's such things w we'll we'll have around the fire.

00:31:55.625 --> 00:32:04.154
<v Wojciech Wegrzynski>You've also investigated a lot about the throttling effect of fires and how this influences the, the ventilation system in the tunnel.

00:32:04.631 --> 00:32:06.938
<v Ingo Riess>well, that's a, that was an interesting project.

00:32:06.968 --> 00:32:15.734
<v Ingo Riess>There was a lot of discussion about the fire trotting effect in since well, I learned about it in 2006, from a paper from conference paper.

00:32:16.252 --> 00:32:27.509
<v Ingo Riess>And, in 20 17, 18, 19, I had a research project funded by the Swiss, road administration to do a CFD analysis on this.

00:32:27.645 --> 00:32:34.236
<v Ingo Riess>and I had some very interesting findings, which contradicted a lot of the papers that were published before.

00:32:34.900 --> 00:32:36.369
<v Ingo Riess>the report was well received.

00:32:37.296 --> 00:32:52.750
<v Ingo Riess>and, but still, to me, this is a CFD study and I did the CFD, myself, so I'd like to mistrust my own results and I would really love, any confirmation or any opposition against those results provided by.

00:32:53.525 --> 00:33:04.327
<v Ingo Riess>Or if possible, even large-scale fire test to validate the results because without, without large-scale fire tests, the value of these results is a bit limited.

00:33:04.691 --> 00:33:15.847
<v Ingo Riess>The current status is that a PhD student has confirmed via the fire throttling effect as found in, in my study in an independent analysis, using different.

00:33:16.530 --> 00:33:18.510
<v Ingo Riess>But still, that's just a verification.

00:33:18.510 --> 00:33:19.590
<v Ingo Riess>That's not a validation.

00:33:20.601 --> 00:33:20.961
<v Wojciech Wegrzynski>Mm.

00:33:21.448 --> 00:33:31.300
<v Ingo Riess>And, currently I'm hoping for funds for a research project where we can actually measure the throttling effect in this Spanish, test facility.

00:33:31.805 --> 00:33:35.738
<v Ingo Riess>But that's rather expensive doing full, size fire tests.

00:33:36.289 --> 00:33:36.647
<v Wojciech Wegrzynski>Yes.

00:33:37.905 --> 00:33:40.685
<v Wojciech Wegrzynski>Uh, so this effect how does it work?

00:33:40.715 --> 00:33:45.875
<v Wojciech Wegrzynski>Like the fire is a resistance to the flow, and you try to measure how big this resistance

00:33:46.185 --> 00:33:47.746
<v Ingo Riess>there are several effects going on.

00:33:47.776 --> 00:34:00.386
<v Ingo Riess>One effect is that the expansion of the heated air in the fire, which causes a local press of drop because of the acceleration that's been newly more or less or momentum balance.

00:34:00.897 --> 00:34:07.228
<v Ingo Riess>And then you have increased friction downstream because of the higher volume you push through the tunnel.

00:34:07.445 --> 00:34:15.190
<v Ingo Riess>And there's another effect downstream from the fire when you have temperature stratification and the flow profile resembles the temperature profile.

00:34:15.681 --> 00:34:18.360
<v Ingo Riess>So it's not the fully developed tube flow.

00:34:18.360 --> 00:34:19.855
<v Ingo Riess>You, you know, from the cold.

00:34:19.864 --> 00:34:19.954
<v Ingo Riess>Yeah.

00:34:20.614 --> 00:34:28.155
<v Ingo Riess>And the, the resistance along the tunnel of this, oddly shaped flow profile is apparently higher than the normal tunnel flow.

00:34:28.668 --> 00:34:30.074
<v Ingo Riess>And this is significant.

00:34:30.327 --> 00:34:31.880
<v Ingo Riess>this fire throttling effect.

00:34:31.880 --> 00:34:37.284
<v Ingo Riess>If this temperature stratification remains stable, that would be relevant for ventilation.

00:34:38.255 --> 00:34:39.215
<v Wojciech Wegrzynski>I've read your report.

00:34:39.244 --> 00:34:40.175
<v Wojciech Wegrzynski>And I loved it.

00:34:40.204 --> 00:34:58.447
<v Wojciech Wegrzynski>And I immediately struck me that again, in the   like when we commissioned the tunnel when we do hot smoke testing in it with, 2, 3, 5 megawatts source in it, and we base our opinion on the observations in that moment of time.

00:34:59.077 --> 00:35:11.701
<v Wojciech Wegrzynski>And you have, Investigated this, I assume, with the relation to the ventilation systems and how it could impact the ventilation system in a negative way.

00:35:11.701 --> 00:35:15.668
<v Wojciech Wegrzynski>Like it's a high resistance that you would have to push against for us.

00:35:15.907 --> 00:35:17.588
<v Wojciech Wegrzynski>It was interesting opposite way.

00:35:17.737 --> 00:35:20.018
<v Wojciech Wegrzynski>Like the wind effects on, on the tunnel fire.

00:35:20.230 --> 00:35:25.186
<v Wojciech Wegrzynski>If the wind is acting on the tunnel, let's say against us.

00:35:25.606 --> 00:35:34.275
<v Wojciech Wegrzynski>And there is this increased resistance that comes from large fire being there, mainly the thermal expansion and this heat pump that I talked.

00:35:34.568 --> 00:35:51.405
<v Wojciech Wegrzynski>Briefly before then maybe the wind effort would have less severity because it will also act against this local and throttle making the whole equation so complex, probably unsolvable because suddenly you have so many forces that act on each other and influence each other.

00:35:51.585 --> 00:35:59.775
<v Wojciech Wegrzynski>But the main point is we pace our opinion on thing that is happening in this brief moment.

00:35:59.775 --> 00:36:02.105
<v Wojciech Wegrzynski>When we do the hotsmoke test.

00:36:02.409 --> 00:36:10.110
<v Wojciech Wegrzynski>Unfortunately not possible with a hundred megawatts or not really welcomed owners have the talent to do that with a hundred megawatts.

00:36:10.679 --> 00:36:18.432
<v Wojciech Wegrzynski>And, in a way, you know, understanding that in reality, it's going to be different because there's going to be different forces acting than we have now.

00:36:19.507 --> 00:36:20.498
<v Ingo Riess>the smoke test.

00:36:20.527 --> 00:36:22.246
<v Ingo Riess>They convey a level of safety.

00:36:22.246 --> 00:36:23.387
<v Ingo Riess>That's not really there.

00:36:23.572 --> 00:36:24.327
<v Ingo Riess>it's very good.

00:36:24.327 --> 00:36:25.317
<v Ingo Riess>For public opinion.

00:36:25.317 --> 00:36:26.726
<v Ingo Riess>You can have a nice movie.

00:36:26.726 --> 00:36:27.867
<v Ingo Riess>You ask you get the smoke.

00:36:27.867 --> 00:36:39.896
<v Ingo Riess>Stratification is also an effect I don't think there was too many real fires where we had a stable smokes layer because usually vehicles are moving in the smoke.

00:36:40.152 --> 00:36:46.572
<v Ingo Riess>there's the fire brigades are, is run rushing in and every movement, like that will disturb the smoke layer.

00:36:46.931 --> 00:36:50.442
<v Ingo Riess>It might not stop the temperature stratification, but the visibility.

00:36:50.514 --> 00:36:50.784
<v Wojciech Wegrzynski>Yeah.

00:36:50.829 --> 00:37:01.554
<v Ingo Riess>And, all these fire tests show very stable smoke stratification So it's, it's again, it's the test and what you see there is it conveys a level of safety that might not be there.

00:37:01.876 --> 00:37:05.867
<v Wojciech Wegrzynski>Well, my experience is that the bigger the fire, the better the stratification though.

00:37:06.197 --> 00:37:06.797
<v Wojciech Wegrzynski>And, uh,

00:37:07.722 --> 00:37:08.291
<v Ingo Riess>Froude number.

00:37:08.291 --> 00:37:14.545
<v Ingo Riess>Yeah, the stronger, the temperature stratification, the strong number, the better the stability of the smoke layers.

00:37:15.391 --> 00:37:25.963
<v Wojciech Wegrzynski>but in reality, I also think that in the hot smoke test, when you immediately set on fire five megawatts pans of diesel and, gasoline, like people did that Austrian style.

00:37:26.023 --> 00:37:26.893
<v Wojciech Wegrzynski>I love that.

00:37:27.331 --> 00:37:40.365
<v Wojciech Wegrzynski>I there's also an unrealistic representation of the growth of the fire, which, which will be growing, which will be, uh, hopefully slower in a way, and may not have this buoyancy or will be spread out, at the larger fire source.

00:37:40.786 --> 00:37:44.715
<v Wojciech Wegrzynski>Not necessarily a point source, like, like a panel would be a point source.

00:37:44.963 --> 00:37:46.793
<v Ingo Riess>and there's also the traffic behavior.

00:37:47.117 --> 00:37:51.257
<v Ingo Riess>there, there were so many, especially in tunnels that got an emergency breakdown.

00:37:51.922 --> 00:37:53.271
<v Ingo Riess>We don't have that in Switzerland.

00:37:53.512 --> 00:38:07.751
<v Ingo Riess>Most tunnels don't have that, but if you have that, the likelihood that a fire occurs on that breakdown lane is probably the highest in the tunnel cross section, which leaves two lanes of traffic free for the vehicles.

00:38:07.811 --> 00:38:19.282
<v Ingo Riess>So maybe the vehicles will not stop in front of the fire as we assume in our safety analysis, but they will continue to go through, they will see close to nothing, but still what they will continue to put.

00:38:20.208 --> 00:38:22.599
<v Ingo Riess>That's how people act.

00:38:23.192 --> 00:38:30.722
<v Wojciech Wegrzynski>and, at the phone for the end we've discussed so many interesting aspects of the tunnel, fire safety and ventilation, and.

00:38:31.175 --> 00:38:35.315
<v Wojciech Wegrzynski>How much research you see about this particular aspects?

00:38:35.346 --> 00:38:48.918
<v Wojciech Wegrzynski>Because, and I mean, in, in like peer reviewed papers, because I see very little, the only places where I really see this research, as a great source of knowledge is you've mentioned Graz conference and that's a place where.

00:38:49.923 --> 00:38:50.884
<v Wojciech Wegrzynski>You can learn a lot.

00:38:51.333 --> 00:38:56.373
<v Wojciech Wegrzynski>There's a PIARC conferences, but in peer reviewed research, I have this odd feeling.

00:38:56.373 --> 00:39:09.704
<v Wojciech Wegrzynski>It's all about critical velocities and backlayering, scale models of tunnels I'm really let down by, by the fact how disconnected or disjoint from the engineering that is.

00:39:10.110 --> 00:39:10.501
<v Ingo Riess>yes.

00:39:10.561 --> 00:39:13.351
<v Ingo Riess>I mean the, the engineers don't read peer reviewed papers.

00:39:14.280 --> 00:39:15.530
<v Ingo Riess>They are too expensive.

00:39:15.559 --> 00:39:17.719
<v Ingo Riess>And usually you don't come across them.

00:39:18.117 --> 00:39:24.592
<v Ingo Riess>Most engineers are not directly connected to a university, so they don't, they simply don't have access to these papers.

00:39:25.056 --> 00:39:35.615
<v Ingo Riess>The only thing they have access to is conferences where the community meets and, the same, the research for these project is done by engineering companies and not at universal.

00:39:36.501 --> 00:39:38.594
<v Ingo Riess>So there's research done in Germany.

00:39:38.594 --> 00:39:41.144
<v Ingo Riess>It's funded by BAST in Switzerland.

00:39:41.144 --> 00:39:43.670
<v Ingo Riess>It's funded by ASTRA, in Austria.

00:39:43.670 --> 00:39:45.981
<v Ingo Riess>And they've got their research program.

00:39:46.130 --> 00:39:48.141
<v Ingo Riess>It's done by engineering companies.

00:39:48.411 --> 00:39:54.471
<v Ingo Riess>And in the past couple of years, there has been some work done on human behavior with a sprinkler systems.

00:39:54.501 --> 00:39:55.827
<v Ingo Riess>And what do people actually do?

00:39:56.760 --> 00:40:05.039
<v Ingo Riess>And we've got due to the European directive we've got by now consider data from real events.

00:40:05.469 --> 00:40:07.840
<v Ingo Riess>This was another change in the last 20 years.

00:40:07.996 --> 00:40:10.306
<v Ingo Riess>Now we really know we get the report.

00:40:10.335 --> 00:40:12.905
<v Ingo Riess>We see what happened, how people behaved,

00:40:13.275 --> 00:40:15.585
<v Wojciech Wegrzynski>We also get the measurements and that's, that's something

00:40:15.715 --> 00:40:18.235
<v Ingo Riess>and we've got more equipment in the tunnel that gives us more date day.

00:40:18.817 --> 00:40:22.322
<v Wojciech Wegrzynski>But I still, I would put the case in the reverse order.

00:40:22.353 --> 00:40:24.916
<v Wojciech Wegrzynski>The scientists are also the engineers and they are.

00:40:24.949 --> 00:40:31.373
<v Wojciech Wegrzynski>Rarely have practical experience designing or solving technical issues in tunnels and, there's a level of.

00:40:31.400 --> 00:40:34.418
<v Wojciech Wegrzynski>Problems that you only learn when you face them.

00:40:34.418 --> 00:40:50.260
<v Wojciech Wegrzynski>And when you match them on, on a real project and that are not evident in a small-scale tunnel in your laboratory, and you can run into this loophole off of critical velocity or back layer in distance, which is very interesting to research.

00:40:50.307 --> 00:40:55.630
<v Wojciech Wegrzynski>I would say it's, fairly easy to research in, your scale models because they are very convenient for that.

00:40:55.661 --> 00:40:55.840
<v Wojciech Wegrzynski>But.

00:40:56.215 --> 00:40:58.885
<v Wojciech Wegrzynski>You've already said you don't use critical velocity.

00:40:58.885 --> 00:41:00.114
<v Wojciech Wegrzynski>And that does not either.

00:41:00.505 --> 00:41:03.775
<v Wojciech Wegrzynski>I do not really care that much about that concept.

00:41:04.014 --> 00:41:07.534
<v Ingo Riess>well, I think the critical velocity is a design requirement.

00:41:07.855 --> 00:41:10.755
<v Ingo Riess>It defines the capacity of the system and.

00:41:11.137 --> 00:41:13.027
<v Ingo Riess>I like the Swiss approach to this.

00:41:13.027 --> 00:41:18.097
<v Ingo Riess>They, the Swiss design code for old tunnel ventilation just says we want three meter per second.

00:41:18.355 --> 00:41:21.324
<v Ingo Riess>They don't, they don't talk about critical velocity at all.

00:41:21.485 --> 00:41:25.065
<v Ingo Riess>We want three meters per second, and I think that's a very sound approach.

00:41:25.190 --> 00:41:30.998
<v Wojciech Wegrzynski>and so much easier then the page long equation to solve for the fourth, significant digits in the

00:41:31.333 --> 00:41:34.632
<v Ingo Riess>And with every new edition of NFPA it changes.

00:41:35.788 --> 00:41:36.027
<v Wojciech Wegrzynski>Yeah.

00:41:36.027 --> 00:41:40.228
<v Wojciech Wegrzynski>So there we've seen the papers that, that actually, and I'm happy with that.

00:41:40.327 --> 00:41:54.731
<v Wojciech Wegrzynski>They started questioning the new values that there are the, they started to be unreasonably high, like unrealistically high end, without really sound proof of why we need as high numbers, because they translate into costs.

00:41:55.485 --> 00:42:05.293
<v Wojciech Wegrzynski>Operational costs, construction costs and, and, they just make it more difficult to design the system, which probably has worked even with the previous versions.

00:42:05.347 --> 00:42:06.967
<v Ingo Riess>and this may be an another program.

00:42:06.967 --> 00:42:10.628
<v Ingo Riess>Why we, we don't research these things enough.

00:42:10.771 --> 00:42:13.590
<v Ingo Riess>there are two, we've got these design codes in Europe.

00:42:14.556 --> 00:42:15.936
<v Ingo Riess>Which are pretty well fixed.

00:42:16.536 --> 00:42:22.753
<v Ingo Riess>And, there are too many energy engineering companies, where people think we already know everything.

00:42:23.313 --> 00:42:25.083
<v Ingo Riess>So they don't do research anymore.

00:42:25.690 --> 00:42:30.639
<v Ingo Riess>if you get, go to the conferences and you see the work that's presented, there it's so much today.

00:42:30.909 --> 00:42:35.643
<v Ingo Riess>There's so much more about projects we did and then no longer questions.

00:42:36.516 --> 00:42:43.342
<v Ingo Riess>And, it goes more into marketing and less into research, which is a pity, because I think there's still a lot of work to do.

00:42:43.943 --> 00:42:44.452
<v Wojciech Wegrzynski>Thank you.

00:42:44.483 --> 00:42:45.356
<v Wojciech Wegrzynski>Thank you for that.

00:42:45.365 --> 00:42:50.460
<v Wojciech Wegrzynski>I'm happy to finally have an engineer in the podcast and well, you're, you're a scientist to me.

00:42:51.570 --> 00:42:58.663
<v Wojciech Wegrzynski>And, was a great pleasure to discuss with you the challenges of resiliency of safety in tunnels, and then eventually ventilation.

00:42:59.432 --> 00:43:02.630
<v Wojciech Wegrzynski>I think a beneficial thing would be to advertise a bit.

00:43:02.630 --> 00:43:12.373
<v Wojciech Wegrzynski>this conferences are the places where the engineering mixes with research and for me, such places is Tunnel Safety Ventilation Conference in Graz.

00:43:12.393 --> 00:43:14.409
<v Wojciech Wegrzynski>And I hope to be there this, this year.

00:43:14.409 --> 00:43:18.682
<v Wojciech Wegrzynski>It's, um, it's in may my ninth to 10th, in GRAZ in Austria.

00:43:18.773 --> 00:43:21.266
<v Wojciech Wegrzynski>And, I'll link to that conference in the bottom.

00:43:21.266 --> 00:43:23.065
<v Wojciech Wegrzynski>You have your favorite conference outside of.

00:43:23.545 --> 00:43:34.150
<v Ingo Riess>well, actually in the, in the past couple of years, I only went to Graz there is The HR conferences, British hydraulic research Institute, which I left 20 years ago.

00:43:34.463 --> 00:43:36.382
<v Ingo Riess>but I didn't have the opportunity to go.

00:43:36.413 --> 00:43:42.246
<v Ingo Riess>They were very innovative and very technical, the ones on ton of fire and ventilation.

00:43:42.739 --> 00:43:46.019
<v Ingo Riess>but I don't know how they develop the past 10 to 15 years.

00:43:46.168 --> 00:43:50.141
<v Wojciech Wegrzynski>there's also PIARC conference in Granada that's happening in October, I think.

00:43:50.141 --> 00:43:51.960
<v Wojciech Wegrzynski>And I hope to be there

00:43:52.030 --> 00:43:57.960
<v Ingo Riess>Yeah, the PIARC conferences, they are more strategic and a state of the art.

00:43:57.990 --> 00:43:59.161
<v Ingo Riess>They are less scientific.

00:43:59.320 --> 00:44:01.208
<v Ingo Riess>it's a different they're different topics.

00:44:01.208 --> 00:44:01.297
<v Ingo Riess>This.

00:44:01.639 --> 00:44:08.773
<v Wojciech Wegrzynski>And I would also like to highlight that, the materials from the technical conferences in Graz are available online usually.

00:44:08.773 --> 00:44:13.003
<v Wojciech Wegrzynski>And you, you can find them, I just see your paper on trotting ethics.

00:44:13.003 --> 00:44:13.932
<v Wojciech Wegrzynski>So it's there.

00:44:14.452 --> 00:44:19.543
<v Wojciech Wegrzynski>That's great that this is being shared outside of the conference to be used.

00:44:19.992 --> 00:44:24.523
<v Wojciech Wegrzynski>So I'll link to this resources and also rulings.

00:44:25.021 --> 00:44:26.521
<v Wojciech Wegrzynski>Research that, that you have been doing.

00:44:26.965 --> 00:44:37.690
<v Wojciech Wegrzynski>Ingo thank you very much for coming here and being a part of the podcast was a, it was a huge pleasure to have you in here and, see you soon on some tunneling project in Europe.

00:44:38.039 --> 00:44:39.210
<v Ingo Riess>thank you for having me.

00:44:39.300 --> 00:44:40.650
<v Ingo Riess>I hope to meet you in God's.

00:44:41.242 --> 00:44:42.280
<v Wojciech Wegrzynski>Looking forward to that.

00:44:42.311 --> 00:44:42.880
<v Wojciech Wegrzynski>See you soon.

00:44:43.891 --> 00:44:44.581
<v Wojciech Wegrzynski>And that's it.

00:44:44.664 --> 00:44:46.159
<v Wojciech Wegrzynski>What a great talk with Ingo.

00:44:46.159 --> 00:44:47.688
<v Wojciech Wegrzynski>I'm really happy to.

00:44:47.704 --> 00:44:55.989
<v Wojciech Wegrzynski>Having discussed with him, especially the risk aspects And he know this whole concept of resiliency and how we could actually build the third.

00:44:56.619 --> 00:45:05.614
<v Wojciech Wegrzynski>Tunnel nodes just to have the tunnel operational for, for the time of refurbishment that's, that's is something very new for me and very intriguing.

00:45:05.614 --> 00:45:07.474
<v Wojciech Wegrzynski>And it makes a lot of sense.

00:45:07.474 --> 00:45:10.954
<v Wojciech Wegrzynski>When you think about the economical impact that tunnels have in.

00:45:12.889 --> 00:45:15.349
<v Wojciech Wegrzynski>here that he doesn't like to do CFD.

00:45:15.817 --> 00:45:17.702
<v Wojciech Wegrzynski>it doesn't feel secure about it.

00:45:17.731 --> 00:45:18.871
<v Wojciech Wegrzynski>Please don't trust him.

00:45:19.081 --> 00:45:24.782
<v Wojciech Wegrzynski>He literally writes his own one dimensional coats for tunnel ventilation and everything.

00:45:24.782 --> 00:45:25.592
<v Wojciech Wegrzynski>So I am.

00:45:25.981 --> 00:45:28.952
<v Wojciech Wegrzynski>Way more confident in his capabilities then.

00:45:29.012 --> 00:45:29.731
<v Wojciech Wegrzynski>He is.

00:45:30.092 --> 00:45:36.362
<v Wojciech Wegrzynski>And I've read his report on throttling ethics, which is linked in the show notes and it is purely excellent.

00:45:36.385 --> 00:45:38.027
<v Wojciech Wegrzynski>One of the best pieces I've read.

00:45:38.027 --> 00:45:38.742
<v Wojciech Wegrzynski>In a long time.

00:45:39.342 --> 00:45:43.048
<v Wojciech Wegrzynski>Uh, so for the end, I think the resources are there.

00:45:43.048 --> 00:45:44.798
<v Wojciech Wegrzynski>You should follow Ingo and researchgate.

00:45:44.818 --> 00:45:46.139
<v Wojciech Wegrzynski>He posts all his reports.

00:45:46.139 --> 00:45:48.929
<v Wojciech Wegrzynski>That's actually the best place to go, I assume.

00:45:49.418 --> 00:45:54.099
<v Wojciech Wegrzynski>we also advertise hard the Graz conference, because it is really good.

00:45:54.489 --> 00:45:56.139
<v Wojciech Wegrzynski>It's a really great conference for everyone.

00:45:56.309 --> 00:45:57.599
<v Wojciech Wegrzynski>Dealing with tunnels.

00:45:58.179 --> 00:45:59.559
<v Wojciech Wegrzynski>it's full of great people, full of grades.

00:45:59.559 --> 00:46:03.818
<v Wojciech Wegrzynski>Research is a great place to be if you're engineering funnels and I hope to be there.

00:46:03.998 --> 00:46:05.018
<v Wojciech Wegrzynski>And I hope to see you there.

00:46:05.858 --> 00:46:07.719
<v Wojciech Wegrzynski>And that's it for the episode.

00:46:07.838 --> 00:46:09.068
<v Wojciech Wegrzynski>Thank you very much.

00:46:09.128 --> 00:46:13.677
<v Wojciech Wegrzynski>And cross fingers for Ukraine and the safety of Ukrainian people, please.

00:46:14.307 --> 00:46:17.097
<v Wojciech Wegrzynski>And let's stop the madmen from blowing up the world.

00:46:17.818 --> 00:46:20.367
<v Wojciech Wegrzynski>Thank you and, uh, see you here next week.

00:46:20.427 --> 00:46:20.878
<v Wojciech Wegrzynski>Cheers.