202 - Designing fire safety with firefighters in mind

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<v Wojciech Węgrzyński>Hello everybody, welcome to Fire Science Show episode 202.

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<v Wojciech Węgrzyński>This time there is no science fiction in the episode, but it's not going to be a hardcore fire science either.

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<v Wojciech Węgrzyński>Well, it is fire science, but from the research perspective I'm going to share some fire safety engineering, my own fire safety engineering today, and I must say it's quite a challenging part of fire safety engineering.

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<v Wojciech Węgrzyński>I've picked a topic that perhaps is a little bit difficult, but I guess it needs to be talked among fire safety engineers as it's a big part of our everyday practice.

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<v Wojciech Węgrzyński>So today we're going to talk about firefighters and fire safety engineering, and I do not mean teaching fire safety engineering to firefighters, I mean firefighters as the part of fire safety engineering.

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<v Wojciech Węgrzyński>For some of you the concept may be odd, but in my law system and I know in many European law systems there are specific clauses of your building code, of your technical codes, that refer to firefighters and providing them with some stuff safeguarding firefighters.

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<v Wojciech Węgrzyński>In my Polish system I have to account their ability to firefight in my design of smoke.

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<v Wojciech Węgrzyński>I have to account their ability to firefight in my design of smoke control systems, for example.

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<v Wojciech Węgrzyński>So there's a direct clause of the law that pretty much tells me you need to account for firefighting in your fire safety engineering and how the heck I do that?

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<v Wojciech Węgrzyński>That's a big question.

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<v Wojciech Węgrzyński>Of course I'm not a firefighter, so I have to figure out something and I'm never sure that it's the best thing, but I'm trying my best and this episode is about destroying your best.

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<v Wojciech Węgrzyński>I'm not going to give you answers of what firefighters want, because if you want to learn that, you can really ask them.

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<v Wojciech Węgrzyński>I think for most of the problems, communication is the answer them.

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<v Wojciech Węgrzyński>I think for most of the problems, communication is the answer.

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<v Wojciech Węgrzyński>However, if you're burdened with having this consideration in your fire safety engineering analysis of some sort, I'll at least share with you some ideas of how I, in my own personal fire safety engineering, account for that.

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<v Wojciech Węgrzyński>And we're going to go through different aspects, one being how soon they will be on the site, so all the timeline aspects of firefighting operations.

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<v Wojciech Węgrzyński>We'll touch a little bit on design fire concepts.

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<v Wojciech Węgrzyński>I think it's highly relevant and highly critical to understand the conditions in which the firefighters will operate.

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<v Wojciech Węgrzyński>We will talk a bit about the conditions in the building and assessment.

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<v Wojciech Węgrzyński>So this whole assessment for me is a part of my CFD calculations or computer modeling of fires in buildings, so I have to account for that in my modeling.

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<v Wojciech Węgrzyński>Therefore, we will talk about how to do that in computer modeling and in the end, I will share some opinions about some tools of fire safety engineering not software, but more like devices, sprinklers, smoke control, etc.

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<v Wojciech Węgrzyński>And how they influence fire safety operations in the building fire and rescue operations in the building.

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<v Wojciech Węgrzyński>I hope this will be an interesting one for you, so let's spin the intro and jump into the episode.

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<v Wojciech Węgrzyński>Welcome to the Firesize Show.

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<v Wojciech Węgrzyński>My name is Wojciech Wigrzyński and I will be your host.

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<v Wojciech Węgrzyński>The FireSense Show is into its third year of continued support from its sponsor, OFAR Consultants, who are an independent, multi-award-winning fire engineering consultancy with a reputation for delivering innovative safety-driven solutions.

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<v Wojciech Węgrzyński>As the UK-leading independent fire risk consultancy, OFAR's globally established team have developed a reputation for pre-em independent fire risk consultancy.

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<v Wojciech Węgrzyński>Ofr's globally established team have developed a reputation for preeminent fire engineering expertise, with colleagues working across the world to help protect people, property and the plant.

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<v Wojciech Węgrzyński>Established in the UK in 2016 as a startup business by two highly experienced fire engineering consultants, the business continues to grow at a phenomenal rate, with offices across the country in eight locations, from Edinburgh to Bath, and plans for future expansions.

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<v Wojciech Węgrzyński>If you're keen to find out more or join OFR Consultants during this exciting period of growth, visit their website at ofrconsultantscom.

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<v Wojciech Węgrzyński>And now back to the episode.

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<v Wojciech Węgrzyński>Okay, let's go.

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<v Wojciech Węgrzyński>This episode is really making me uncomfortable.

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<v Wojciech Węgrzyński>Okay, let's go.

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<v Wojciech Węgrzyński>This episode is really making me uncomfortable and I have quite a big moral dilemma whether I should talk about this or I should not talk about this subject.

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<v Wojciech Węgrzyński>You know, accounting for firefighters in my engineering is not something I would like to do because I'm not a firefighter.

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<v Wojciech Węgrzyński>I'm not.

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<v Wojciech Węgrzyński>I'm simply not a firefighter and it's very hard for me to grasp what exactly a firefighter would like to have in a fire.

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<v Wojciech Węgrzyński>I've quenched some fires I would not say I've battled fires but I have some experience on putting water into fires, even large fires.

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<v Wojciech Węgrzyński>I have experience in trying to control fire with firefighting operations.

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<v Wojciech Węgrzyński>I have experience with ventilation, vast experience with ventilation.

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<v Wojciech Węgrzyński>I understand the smoke flow and et cetera.

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<v Wojciech Węgrzyński>I understand compartment fire dynamics, but I'm not a firefighter and I thought maybe I should not talk about this because it just feels wrong.

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<v Wojciech Węgrzyński>But then again, my everyday engineering, the building code, does not clarify I'm a firefighter the technical guidances that tell me to account for firefighting.

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<v Wojciech Węgrzyński>they don't distinguish whether you're a fire safety engineer who by chance is a volunteer firefighter or who, by chance has professional firefighting experience.

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<v Wojciech Węgrzyński>The system doesn't identify that.

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<v Wojciech Węgrzyński>You are just supposed to account that volunteer firefighter or who by chance has professional firefighting experience the system doesn't identify that you are just supposed to account that someone put a clause in the law, and perhaps for better.

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<v Wojciech Węgrzyński>They put the clause in the law because it makes us reflect on what we're doing and it just forces us for this thing, this aspect, this inclusion of firefighting to be a part of firefight safety engineering.

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<v Wojciech Węgrzyński>Perhaps it's better, perhaps that's a good thing, perhaps if we were not forced to that, we would be too uncomfortable to do it on our own.

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<v Wojciech Węgrzyński>So maybe this for the better.

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<v Wojciech Węgrzyński>Therefore, I think it's fair to discuss, as I'm doing this anyway.

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<v Wojciech Węgrzyński>We can as well discuss on how I believe to do it the best I can, and that's the spirit of this episode.

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<v Wojciech Węgrzyński>So in this episode, I'm going to have to put a disclaimer.

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<v Wojciech Węgrzyński>This is not an outcome of any research project.

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<v Wojciech Węgrzyński>This is not something I would call an unbiased fire science.

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<v Wojciech Węgrzyński>This is very biased fire safety engineers opinion about their craft.

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<v Wojciech Węgrzyński>This is me, wojciech, a fire safety engineer, talking with you, fellow fire safety engineers and fire scientists, on how I do my engineering, and there is a good chance someone can do it better, someone can do it in a different way, someone can achieve their goals in a different pathway than mine.

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<v Wojciech Węgrzyński>Uh, that's pretty fine.

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<v Wojciech Węgrzyński>That's that's really good and I would love to share.

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<v Wojciech Węgrzyński>I would love to learn from you.

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<v Wojciech Węgrzyński>Anyway, let's let's move on and discuss on how to include, for, uh, firefighting operations in the building.

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<v Wojciech Węgrzyński>First, what does it even mean?

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<v Wojciech Węgrzyński>Like what does it even mean that I account for firefighting in my building?

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<v Wojciech Węgrzyński>Do I make provisions that allow firefighters for firefighting and, if so, what kind of provisions would that be?

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<v Wojciech Węgrzyński>Do I control the fire in some way until the firefighters arrive?

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<v Wojciech Węgrzyński>Am I supposed to protect the building in some specific way that allows for firefighting?

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<v Wojciech Węgrzyński>I think it can go pretty deep and I think we're going to touch most of those layers in the podcast episode.

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<v Wojciech Węgrzyński>But let's start with the rival.

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<v Wojciech Węgrzyński>Let's start with firefighters getting to your building.

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<v Wojciech Węgrzyński>And I must say in Poland I'm not personally doing that in my engineering, but I saw many consulting companies would do that.

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<v Wojciech Węgrzyński>They would try and estimate the time to arrival, the time to arrival of firefighters into their buildings and put a number in their report.

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<v Wojciech Węgrzyński>It takes 14 minutes for firefighters to come from the nearest fire station to this building and they put this as a number.

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<v Wojciech Węgrzyński>You know, that defines the timeline, defines at what point the firefighters will be able to fight fire in that building as always.

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<v Wojciech Węgrzyński>I'm comfortable with that, and there are multiple reasons.

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<v Wojciech Węgrzyński>One is that fire station location is I mean it's pretty stable, but at the same time it's temporary.

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<v Wojciech Węgrzyński>We design buildings to last for 50, 100 years.

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<v Wojciech Węgrzyński>You cannot assure that a fire station that is there at some specific point where you design the building will be there for the next 100 years.

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<v Wojciech Węgrzyński>There's no kind of social contract you can sign to make sure that the conditions at the day of design will be unchanged for the entirety of the life of the building.

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<v Wojciech Węgrzyński>So that's one uncertainty that I'm very uncomfortable with.

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<v Wojciech Węgrzyński>Another thing is the time itself, how long it takes the firefighters to come, and I would distinguish like three specific periods of time that I think should be considered in this part.

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<v Wojciech Węgrzyński>One is how long it takes to successfully notify the fire brigade that there is a fire in the building.

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<v Wojciech Węgrzyński>The second one is how long it takes them to arrive to your building.

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<v Wojciech Węgrzyński>And the third one is how long it takes from their arrival to a point in time in which they efficiently can apply water.

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<v Wojciech Węgrzyński>So first, how long it takes them to be notified, this largely depends on the types of systems you have in your building.

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<v Wojciech Węgrzyński>I'm mostly dealing with larger buildings in the ITB in the work that we're doing, so I'm used to working with buildings that are already very well equipped with different fire safety systems, and having a fire alarm system is kind of prerequisite for us to be on the building.

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<v Wojciech Węgrzyński>Even so, we pretty much never work with buildings which would not have fire alarm systems and therefore I can to some extent rely on the fact that a fire alarm will be triggered by the fire.

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<v Wojciech Węgrzyński>Therefore, at the early stages of fire, I can assume that the fire will be detected in the building.

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<v Wojciech Węgrzyński>Now what's going to happen after a fire is detected in the building?

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<v Wojciech Węgrzyński>I have a whole episode about what happens in the building after a fire is detected in the building.

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<v Wojciech Węgrzyński>I have a whole episode about what happens in the building after a fire is detected.

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<v Wojciech Węgrzyński>You can listen to that if you want to understand more about fire automation and all the sequence of things that happens.

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<v Wojciech Węgrzyński>But once the fire is detected in building, multiple things can happen due to the action of the people inside the building.

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<v Wojciech Węgrzyński>So even if you have a system that will automatically transmit the alarm to the fire brigade, it will only do so if the fire is confirmed and the fire can be confirmed by manual operation of the people at the building.

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<v Wojciech Węgrzyński>It can be automatically confirmed if you, for example, have a second detector going into alarm and you have a program that tells you, okay, if two detectors come, this means it's a confirmed fire.

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<v Wojciech Węgrzyński>It can also be confirmed if sufficient time passes from the first detection to, let's say we call it times T1, t2.

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<v Wojciech Węgrzyński>They refer to the operations of the crew at the building.

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<v Wojciech Węgrzyński>So there's a specific amount of time that the team at the building has to confirm or decline a fire.

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<v Wojciech Węgrzyński>And if they do not take any action and this time simply passes, then the fire is also considered confirmed.

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<v Wojciech Węgrzyński>If someone pulls a manual alarm after automated alarm is also confirmed.

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<v Wojciech Węgrzyński>So multiple ways you can confirm an alarm.

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<v Wojciech Węgrzyński>But there's so multiple ways you can confirm an alarm.

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<v Wojciech Węgrzyński>But there's also multiple ways you can delay this.

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<v Wojciech Węgrzyński>The people who are working at the building.

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<v Wojciech Węgrzyński>They can cancel the fire alarm.

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<v Wojciech Węgrzyński>They are able to ignore it for some period of time At some point.

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<v Wojciech Węgrzyński>It's probably impossible to ignore it if it's a large fire and it triggers multiple sensors.

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<v Wojciech Węgrzyński>But if it's a small fire and it's in see.

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<v Wojciech Węgrzyński>But if it's a small fire and it's in sepian stage.

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<v Wojciech Węgrzyński>It's possible to delay that by manual operations of the people inside the building.

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<v Wojciech Węgrzyński>Now, if the building is unmanned in terms of fire alarm central, then it's going to be automated and I assume at least in our system, most of the buildings would be fit with transmission devices which would send a signal to the fire brigade and inform them that there is a fire in this building.

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<v Wojciech Węgrzyński>Sometimes it would even inform them in what relevant part of the building the fire is, if such a distinction is put in place.

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<v Wojciech Węgrzyński>If there is a crew in the building, I assume the automated information also passes through.

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<v Wojciech Węgrzyński>But there will also be a human contact with the Far Brigade, telling them what's happening and probably guiding them.

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<v Wojciech Węgrzyński>Now, this timeline to notification.

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<v Wojciech Węgrzyński>It sounds like immediate, but it can really be a long time which we have to address.

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<v Wojciech Węgrzyński>So we cannot ignore it.

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<v Wojciech Węgrzyński>It's not like 60 seconds in the fire.

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<v Wojciech Węgrzyński>The fire brigade already knows it may take quite a long time for them to be notified about the fire, and the better the fire automation systems in the building, the better the fire alarm system in the building and the higher trained the people staffed in the building, the shorter this time will be.

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<v Wojciech Węgrzyński>The second one is time to arrival, and here I don't really have that much to comment.

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<v Wojciech Węgrzyński>I know that the firefighters operate very quickly, so as soon as they will be notified, you can expect the team to be dispatched in literally minutes and they will come to your building as soon as possible.

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<v Wojciech Węgrzyński>Some people try to establish that with a simple Google map directions from the fire station to the building.

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<v Wojciech Węgrzyński>How long it takes?

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<v Wojciech Węgrzyński>It is an approximation, I guess, and perhaps not even the worst one, so you can pretty much say how much time can pass from the firefighters leaving the fire station and arriving to your building.

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<v Wojciech Węgrzyński>And the third thing is what's going to happen when they arrive to your building.

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<v Wojciech Węgrzyński>I think this is very, very interesting.

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<v Wojciech Węgrzyński>So here I would like to jump into an episode of podcast that I've recorded.

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<v Wojciech Węgrzyński>Three years ago it was episode 51 with a good friend, szymon Kokot, and Szymon is one of the most well-known FAR instructors in the world, I guess Definitely the most known in Poland.

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<v Wojciech Węgrzyński>A good friend of mine and I had this podcast episode with Shimon about looking on fire science through the eyes of a firefighter, so really doing something like in today's episode, but talking to an actual firefighter.

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<v Wojciech Węgrzyński>And I've asked him Shimon, what happens when a fire brigade arrives on the scene?

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<v Wojciech Węgrzyński>What are the things that you consider?

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<v Wojciech Węgrzyński>So I would just like to play a short response of Shimon to that question, because he's a firefighter, he knows what he's saying.

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<v Wojciech Węgrzyński>So I want you to hear the commentary from Shimon, and then I'll probably enhance this with some thoughts of my own.

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<v Wojciech Węgrzyński>So let's play the sample.

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<v Wojciech Węgrzyński>Let's go to the car park.

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<v Wojciech Węgrzyński>Let's tell the fire engineers what the firefighter does when they get a call that the car park is on fire and it's underground.

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<v Wojciech Węgrzyński>We already agreed that.

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<v Wojciech Węgrzyński>Okay, multi-level underground car park.

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<v Szymon Kokot>So, based on experience, there is a PDA predetermined attendance.

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<v Szymon Kokot>That's probably a very British term.

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<v Szymon Kokot>Like a minimum of vehicles and personnel that absolutely has to be dispatched to this kind of event as a minimum.

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<v Szymon Kokot>First, let's say serving, and then, when the commander is on scene, he or she will decide if it's enough or will they need more.

00:16:03.489 --> 00:16:07.645
<v Szymon Kokot>Now this decision is based on multiple factors.

00:16:07.645 --> 00:16:11.115
<v Szymon Kokot>They need more Now.

00:16:11.115 --> 00:16:12.039
<v Szymon Kokot>This decision is based on multiple factors.

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<v Szymon Kokot>If this is a building that was in the area for some time, there is an increased chance that they know the layout of the building.

00:16:16.095 --> 00:16:21.707
<v Szymon Kokot>If it's a new one, maybe there was just one visit or maybe there was no exercise yet.

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<v Szymon Kokot>We have operational planning that envisages going to all major or complex buildings you know frequently, or at least try to put them on the list and check them one after another, because it's a maze, the problem like whatever.

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<v Szymon Kokot>When I sometimes teach the firefighters in the factory, I tell them the difference.

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<v Szymon Kokot>You know what is your advantage.

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<v Szymon Kokot>You know the buildings, you know exactly the building.

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<v Szymon Kokot>So next, you know what is your advantage.

00:16:49.366 --> 00:16:49.549
<v Szymon Kokot>You know the buildings.

00:16:49.549 --> 00:16:49.744
<v Szymon Kokot>You know exactly the buildings.

00:16:49.744 --> 00:16:55.460
<v Szymon Kokot>So next time you just are walking around, you know eating your donut, chatting with your friend, just have a look around.

00:16:55.460 --> 00:16:57.221
<v Szymon Kokot>This is your great advantage.

00:16:57.956 --> 00:17:01.643
<v Szymon Kokot>When we are attending a fire, we basically don't know where we are going.

00:17:01.643 --> 00:17:02.465
<v Szymon Kokot>That's one thing.

00:17:02.465 --> 00:17:07.175
<v Szymon Kokot>The second thing we take into consideration what is the time of the day?

00:17:07.175 --> 00:17:08.997
<v Szymon Kokot>The second thing we take into consideration what is the time of the day?

00:17:08.997 --> 00:17:12.097
<v Szymon Kokot>If it's evening till morning, the car park is mostly full.

00:17:12.097 --> 00:17:15.059
<v Szymon Kokot>If it's the other part of the day, it's mostly empty.

00:17:15.359 --> 00:17:26.885
<v Szymon Kokot>So fire load, fire load, but also the ability or the easiness to travel around it without being disoriented, because obviously you have to throw in limited visibility.

00:17:26.885 --> 00:17:29.307
<v Szymon Kokot>If it's limited visibility, it's smoke.

00:17:29.307 --> 00:17:31.528
<v Szymon Kokot>If it's smoke, it means breathing protection.

00:17:31.528 --> 00:17:33.890
<v Szymon Kokot>Breathing protection has limited time.

00:17:33.890 --> 00:17:48.442
<v Szymon Kokot>So, depending on also depending on another, let's say, science, which is ergonomics, you have to be able to assess it's not entirely the case of the fire commander, because every firefighter has to know this for themselves how much air they are using.

00:17:48.442 --> 00:18:03.355
<v Szymon Kokot>Is it 50, 60, 70, 80 liters per minute, based on different types of work moderate work, heavy work or so on, or, more practically, they have to just read the gauge of their BA pressure frequently enough and be able to communicate, if we want to communicate.

00:18:03.535 --> 00:18:11.538
<v Szymon Kokot>There's a problem with concrete floors which blocks the signal, so there's a number of difficulties.

00:18:11.538 --> 00:18:27.383
<v Szymon Kokot>What is the average ability of a firefighter to combat fire, be it cool smoke, be it attack the seat of the fire, and if I'm having today an average firefighter, a very good firefighter or a poor firefighter?

00:18:27.383 --> 00:18:29.867
<v Szymon Kokot>It's a great set of variables.

00:18:30.394 --> 00:18:33.222
<v Wojciech Węgrzyński>So there's many levels of constraints.

00:18:33.222 --> 00:18:51.400
<v Wojciech Węgrzyński>You have to take into account the time you can send people for a certain amount of time until their breathing apparatus stops working, and probably you need to secure the logistics how to exchange them, pull them out early enough so that they don't work.

00:18:51.961 --> 00:19:04.838
<v Szymon Kokot>yeah, they don't work on the reserve, because it's basically being in the danger zone, working on reserve, but also being able to send in someone in exchange so that we have a continuous firefighting operation.

00:19:05.359 --> 00:19:09.426
<v Wojciech Węgrzyński>Then you mentioned communication, which also can be blocked by the building itself.

00:19:09.426 --> 00:19:09.788
<v Wojciech Węgrzyński>It can.

00:19:11.575 --> 00:19:15.163
<v Szymon Kokot>Then visibility Do I have thermal imaging cameras?

00:19:15.163 --> 00:19:23.421
<v Szymon Kokot>Now, that's a piece of scientific equipment, you know, like reading thermal radiation from emitting objects, which, by the way, is also.

00:19:23.421 --> 00:19:24.459
<v Szymon Kokot>They need to understand.

00:19:24.459 --> 00:19:27.511
<v Szymon Kokot>This is not a thermometer, this is an assessment.

00:19:27.511 --> 00:19:29.557
<v Szymon Kokot>If it's heavy smoke, there's a lot of soot.

00:19:29.917 --> 00:19:36.680
<v Wojciech Węgrzyński>You will not be able to see through it okay, I'm back and, uh, it was fun to revisit episode 51 with shimon.

00:19:36.680 --> 00:19:42.603
<v Wojciech Węgrzyński>I recommend you listening to that one because it's a firefighter speaking about firefighting, so he's much more fit than me to talk about it.

00:19:42.603 --> 00:19:55.474
<v Wojciech Węgrzyński>Anyway, the things that shimon mentioned were not first things that came to my mind when I imagined what a fire brigade may do at the site, and there indeed is a ton of considerations to be done at the site.

00:19:55.474 --> 00:20:09.016
<v Wojciech Węgrzyński>What I wanted to achieve with this walk down memory lane and bringing back Shimon into the podcast episode is to highlight that the fact that firefighters arrived in your building does not mean the fire has stopped.

00:20:09.016 --> 00:20:14.107
<v Wojciech Węgrzyński>It does not mean that the water is on the fire and immediately the action is being taken.

00:20:14.107 --> 00:20:23.583
<v Wojciech Węgrzyński>And, depending on how complicated your building is, how large your building is, it can take considerable amount of time to reach the location of the fire.

00:20:23.583 --> 00:20:26.076
<v Wojciech Węgrzyński>That's the problem with Mastimber, for example.

00:20:26.076 --> 00:20:29.517
<v Wojciech Węgrzyński>We highly rely on firefighters' intervention in Mastimber.

00:20:29.517 --> 00:20:33.519
<v Wojciech Węgrzyński>They literally have to be there because the structure is participating in the fire.

00:20:33.519 --> 00:20:42.580
<v Wojciech Węgrzyński>Therefore, it must be actively battled, and if they have to climb 30 flights of stairs, it's going to be difficult.

00:20:42.580 --> 00:20:48.682
<v Wojciech Węgrzyński>At the point when they reach the fire they will be already exhausted and that their job has not even started yet.

00:20:48.682 --> 00:20:51.483
<v Wojciech Węgrzyński>Therefore, there's a lot to be accounted for.

00:20:51.483 --> 00:20:58.748
<v Wojciech Węgrzyński>Firefighters appearing in your sight does not mean that they have started fighting fire.

00:20:58.748 --> 00:21:15.355
<v Wojciech Węgrzyński>Perhaps I'll invite someone from FSRI to discuss this in a much deeper state, because FSRI is working a lot with firefighters and they have prepared those great considerations for firefighting, so maybe we will be able to narrow down the timeline a little bit better.

00:21:15.355 --> 00:21:33.544
<v Wojciech Węgrzyński>For me, the important thing is that it just can take a lot of time, and the bigger, the more complicated building I am designing, the more time it's going to take and more reliant on my fire engineering those firefighters will be to reach the point where they can fight fire.

00:21:34.085 --> 00:21:40.185
<v Wojciech Węgrzyński>Okay, the other thing is, the fire brigade was notified, they were dispatched, they've arrived to the scene.

00:21:40.185 --> 00:21:42.298
<v Wojciech Węgrzyński>At the same time the fire was growing.

00:21:42.298 --> 00:21:45.346
<v Wojciech Węgrzyński>Kind of right, we have a fire developing in our building.

00:21:45.346 --> 00:21:57.640
<v Wojciech Węgrzyński>So now, if I try to do any sort of engineering assessment, what would be the conditions when the firefighters arrive or when the firefighters start their firefighting operations?

00:21:57.640 --> 00:22:00.326
<v Wojciech Węgrzyński>This is what my clause of the building code tells me to do.

00:22:00.326 --> 00:22:01.498
<v Wojciech Węgrzyński>I have to account for that.

00:22:01.498 --> 00:22:09.977
<v Wojciech Węgrzyński>So I have to in some way assess in what conditions, they will be able to start their firefighting operations in the building right.

00:22:09.977 --> 00:22:15.195
<v Wojciech Węgrzyński>So if I want to do that, I need to understand how big the fire is at that point.

00:22:15.195 --> 00:22:20.425
<v Wojciech Węgrzyński>And it's quite intriguing because many people do not realize that.

00:22:20.445 --> 00:22:35.740
<v Wojciech Węgrzyński>But in some design fires you already have that as an integral part of your design fire, for example, the TNO fire for vehicles, one that I've praised a lot of times in this podcast and I like it a lot.

00:22:35.740 --> 00:22:47.363
<v Wojciech Węgrzyński>But it kind of assumes that around 20th minute you will have an intervention and this is the reason why the fire stops growing, because there's a firefighting intervention.

00:22:47.363 --> 00:22:51.424
<v Wojciech Węgrzyński>And indeed those firefighting interventions can be very, very efficient.

00:22:51.424 --> 00:23:02.968
<v Wojciech Węgrzyński>In car parks, bre experiments, for example if you go back to them you will see that experiment, one the one with three vehicles, very huge growth fire, very large fire in a very small space.

00:23:02.968 --> 00:23:09.228
<v Wojciech Węgrzyński>But as soon as they applied water it really dropped the heat release rate and they controlled it very quickly.

00:23:09.228 --> 00:23:12.325
<v Wojciech Węgrzyński>So we also know that those interventions can be very efficient.

00:23:12.734 --> 00:23:18.428
<v Wojciech Węgrzyński>But okay, what state the fire will be when those firefighters can start their work?

00:23:18.428 --> 00:23:20.881
<v Wojciech Węgrzyński>And now it's pretty uncertain.

00:23:20.881 --> 00:23:24.761
<v Wojciech Węgrzyński>Of course, like everything in fire safety engineering, fires are growing.

00:23:24.761 --> 00:23:28.925
<v Wojciech Węgrzyński>We mostly consider growing fires, some kind of alpha-thisquad fires.

00:23:28.925 --> 00:23:36.308
<v Wojciech Węgrzyński>That's a relationship that fairly well captures the growth of fires in most types of buildings that we deal with.

00:23:36.875 --> 00:23:38.623
<v Wojciech Węgrzyński>But fires can also be limited.

00:23:38.623 --> 00:23:52.067
<v Wojciech Węgrzyński>Fires can reach some sort of steady state or quasi-steady state, and if they reach a steady state the job becomes easy because you just assess what the steady state fire science is, then look for the conditions in that steady state.

00:23:52.067 --> 00:23:55.304
<v Wojciech Węgrzyński>The steady state can be reached through different ways.

00:23:55.304 --> 00:23:55.805
<v Wojciech Węgrzyński>To be honest.

00:23:55.805 --> 00:24:06.290
<v Wojciech Węgrzyński>One is when you have a fire confined to a small compartment, your fire size will be highly related to the openings and ventilation in the compartment.

00:24:06.290 --> 00:24:09.105
<v Wojciech Węgrzyński>So it's classical compartment fire dynamics.

00:24:09.105 --> 00:24:17.621
<v Wojciech Węgrzyński>You can tell the maximum size of a fire in a compartment knowing what kind of openings the compartment has, and you cannot skip physics.

00:24:17.621 --> 00:24:18.941
<v Wojciech Węgrzyński>It's not going to be larger than that.

00:24:18.941 --> 00:24:20.855
<v Wojciech Węgrzyński>It could be larger, but outside.

00:24:20.855 --> 00:24:35.237
<v Wojciech Węgrzyński>So perhaps if your compartment is lined with timber or you have some just ridiculous amount of fuel inside your compartment, the fuel will burn out outside of that compartment when it gets oxygen in the exterior conditions.

00:24:35.237 --> 00:24:39.919
<v Wojciech Węgrzyński>That's a different thing, in some cases highly important, in some cases not that relevant.

00:24:39.919 --> 00:24:45.497
<v Wojciech Węgrzyński>But in terms of the compartment itself, the size of the fire, there is a maximum limit to that.

00:24:45.497 --> 00:24:47.222
<v Wojciech Węgrzyński>That comes from physics.

00:24:47.222 --> 00:24:47.584
<v Wojciech Węgrzyński>That's it.

00:24:47.584 --> 00:24:50.673
<v Wojciech Węgrzyński>It can also be limited by availability of the fuel.

00:24:50.673 --> 00:25:07.907
<v Wojciech Węgrzyński>So every compartment fire until there's a flashover is basically a collection of single items burning or groups of items that are burning, and if you have a vehicle parked in the middle of a car park and there is no other vehicle around it, the fire cannot spread.

00:25:07.907 --> 00:25:08.429
<v Wojciech Węgrzyński>That's it.

00:25:08.429 --> 00:25:14.084
<v Wojciech Węgrzyński>If there's no fuel package to which the fire can jump, then the fire is not able to spread.

00:25:14.304 --> 00:25:30.778
<v Wojciech Węgrzyński>Now, this is pretty tricky to design for, because you have to understand the exact location of the fuel in your building and the type of fuel if you're building, and the conditions at which the fuel may ignite or may not ignite, and you probably also need some sort of control over that.

00:25:30.778 --> 00:25:32.603
<v Wojciech Węgrzyński>This exact fuel will be in the building.

00:25:32.603 --> 00:25:36.034
<v Wojciech Węgrzyński>So if you are designing a car park, you really hope there is not going to be a garage sale or something in the building.

00:25:36.034 --> 00:25:42.678
<v Wojciech Węgrzyński>So if you are designing a car park, you really hope there is not going to be a garage sale or something in the car park, because that's a completely different hazard than the one you designed for.

00:25:42.678 --> 00:25:52.257
<v Wojciech Węgrzyński>Vincent Brennan once told me that if there is a space you have to consider a wedding being placed there and people would put weddings into most ridiculous spaces.

00:25:52.257 --> 00:25:54.220
<v Wojciech Węgrzyński>So I can actually imagine a wedding in a car park.

00:25:54.220 --> 00:25:56.644
<v Wojciech Węgrzyński>So that's a hazard I usually do not design for.

00:25:56.905 --> 00:26:02.355
<v Wojciech Węgrzyński>But in your classical case the fire can spread through, of course, direct flame contact.

00:26:02.355 --> 00:26:08.859
<v Wojciech Węgrzyński>That's probably the easiest, and if it happens it will most likely spread to any type of combustible material.

00:26:08.859 --> 00:26:10.465
<v Wojciech Węgrzyński>It can spread to radiation.

00:26:10.465 --> 00:26:23.519
<v Wojciech Węgrzyński>That one is a little bit more challenging because you really need a lot of radiation to ignite things, and the radiation from a flame to its surroundings, if it's fairly small flame, is actually not that intense to ignite at high distances.

00:26:23.519 --> 00:26:27.457
<v Wojciech Węgrzyński>Of course, if you have like 10 megawatt fire it can ignite a lot of stuff around.

00:26:27.457 --> 00:26:34.500
<v Wojciech Węgrzyński>But if it's a few hundred kilowatts, one megawatt really, the distance at which you're unable to ignite is pretty small.

00:26:34.500 --> 00:26:39.288
<v Wojciech Węgrzyński>But you may also have radiation from the smoke layer and that changes the dynamic a lot.

00:26:39.288 --> 00:26:42.384
<v Wojciech Węgrzyński>So yeah, it's something you can account for.

00:26:42.384 --> 00:26:56.151
<v Wojciech Węgrzyński>It can also ignite through convective heating, some sort of firebrands or flamelets that are flying parts of your burning item that are falling apart from that item and flying through your building.

00:26:56.151 --> 00:26:57.921
<v Wojciech Węgrzyński>They can also ignite very easily.

00:26:57.921 --> 00:27:08.577
<v Wojciech Węgrzyński>A classic new example is lithium ion batteries, where you start having your individual cells flying around your building and igniting stuff at different locations.

00:27:08.577 --> 00:27:12.047
<v Wojciech Węgrzyński>This is a pretty crazy fire scenario but yeah, it can happen like that.

00:27:12.555 --> 00:27:32.566
<v Wojciech Węgrzyński>But anyway, if you assume that the fire cannot spread and you put a limiting size of your fire because of that, you have to be really confident in the design and you probably have to have some sort of way to execute that, to really enforce the fact that the fuel packages in your building will be exactly what you've just described in your fire safety engineering or your fire strategy.

00:27:32.566 --> 00:27:41.896
<v Wojciech Węgrzyński>In some cases, when you have large spaces, open spaces, the fire will turn into a traveling fire, and that's something we've discussed with Professor Guillermo Reyn in the podcast.

00:27:41.896 --> 00:27:50.846
<v Wojciech Węgrzyński>In a traveling fire, basically, the concept is the fire is continuously spreading, but it's not so fast that it takes the entire compartment within a minute or two.

00:27:50.846 --> 00:27:57.488
<v Wojciech Węgrzyński>Therefore, some of the fuel burns out and eventually you have one front of fire spread.

00:27:57.488 --> 00:28:10.606
<v Wojciech Węgrzyński>That fire spreads to the nearby objects and moves through your building and the second front of decaying fire, where it's just burning away the fuel package that it just consumed.

00:28:10.606 --> 00:28:16.826
<v Wojciech Węgrzyński>Therefore, it cannot burn anymore and overall it looks like the fire is traveling through a building.

00:28:17.295 --> 00:28:31.827
<v Wojciech Węgrzyński>I remember when we were doing first Obora X1 experiment and it was supposed to confirm or disprove the hypothesis that traveling fires exist and that the fires can travel through the fuel package.

00:28:31.827 --> 00:28:37.000
<v Wojciech Węgrzyński>And I remember I was burdened with securing the perimeter with a good friend, francesco Restuccia.

00:28:37.000 --> 00:28:51.011
<v Wojciech Węgrzyński>So we were at one part of the building and we were putting water on the roof structure outside of the building because the fire was venting through open windows outside and we had the roof structures that we really did not want to lose.

00:28:51.011 --> 00:28:57.508
<v Wojciech Węgrzyński>Therefore we were applying water and we had this fire know, fire spread front, move in front of us.

00:28:57.508 --> 00:29:15.464
<v Wojciech Węgrzyński>So our perimeter was burning and, uh, quite some minutes later we see, you know, this fire decaying and, kind of, you know, going down, moving away from us, and we're like, oh, thank god that fires travel, because I'm not sure how long more we could handle this perimeter.

00:29:15.464 --> 00:29:17.188
<v Wojciech Węgrzyński>So it was good that fires traveled.

00:29:18.476 --> 00:29:21.766
<v Wojciech Węgrzyński>You may also have the fire size limited by firefighting operations.

00:29:21.766 --> 00:29:28.857
<v Wojciech Węgrzyński>So if firefighters arrive off the scene, they start applying water to your building, to your compartment, the fire size.

00:29:28.857 --> 00:29:30.202
<v Wojciech Węgrzyński>You can consider that.

00:29:30.202 --> 00:29:35.804
<v Wojciech Węgrzyński>That's the point at which the outcome is very uncertain and highly reliant on the firefighting capabilities.

00:29:35.804 --> 00:29:40.547
<v Wojciech Węgrzyński>So therefore I don't see any point to grow the fire anymore beyond that point.

00:29:40.547 --> 00:29:43.505
<v Wojciech Węgrzyński>But you really have to have in mind the time at which they will come.

00:29:43.505 --> 00:29:47.605
<v Wojciech Węgrzyński>So you really need to understand at what point of alpha T squared fire.

00:29:47.605 --> 00:29:52.846
<v Wojciech Węgrzyński>The T is the time where the firefighters intervene and my growth stops.

00:29:52.846 --> 00:30:03.397
<v Wojciech Węgrzyński>The growth may also stop because you have some kind of system in your building that simply limits the spread of the fire, like a sprinkler system, like water mist system, like foam system.

00:30:03.498 --> 00:30:09.818
<v Wojciech Węgrzyński>Any fixed firefighting system should, by design, prevent the spread of fire or limit the spread of fire.

00:30:09.818 --> 00:30:17.241
<v Wojciech Węgrzyński>So if you have one of those in your buildings, I think it's a fair assumption to find some kind of steady state fire size and design for that.

00:30:17.241 --> 00:30:24.359
<v Wojciech Węgrzyński>And I would put forward that you could potentially slow or stop the spread with smoke control.

00:30:24.359 --> 00:30:31.106
<v Wojciech Węgrzyński>Not always, in some circumstances you could and it probably would be very difficult, but many people say you could not.

00:30:31.106 --> 00:30:45.010
<v Wojciech Węgrzyński>But I would put forward that you potentially could significantly influence the spread of fire in your building through smoke control, especially if you're able to remove the heat from your ceiling and you prevent the smoke layer to radiate on the fuel packages.

00:30:45.010 --> 00:30:51.682
<v Wojciech Węgrzyński>I think it's a considerable action of smoke control and could be accounted for, but again, highly uncertain.

00:30:51.682 --> 00:30:57.738
<v Wojciech Węgrzyński>So, as you see, the design of fire is quite a problem because it really is an uncertain consideration.

00:30:57.738 --> 00:31:00.066
<v Wojciech Węgrzyński>It really is From my perspective.

00:31:00.105 --> 00:31:13.957
<v Wojciech Węgrzyński>All the fires are growing and for the perspective of assessing the conditions for firefighters, I need to know a number, I need to have a number of the size of the fire at which they have started their intervention, to assess what's happening in the building.

00:31:13.957 --> 00:31:20.625
<v Wojciech Węgrzyński>And it's probably some of the most challenging fire safety engineering decisions that I'm taking in my professional career.

00:31:20.625 --> 00:31:21.976
<v Wojciech Węgrzyński>At what level?

00:31:21.976 --> 00:31:27.607
<v Wojciech Węgrzyński>I stop the size of the fire and I assess and I say this is the fires they will fight.

00:31:27.607 --> 00:31:31.502
<v Wojciech Węgrzyński>Therefore, I'm assessing their ability to enter the building.

00:31:31.502 --> 00:31:38.865
<v Wojciech Węgrzyński>Well, we'll just go in there in a minute, but I just stop at this fire size and I do my fire safety engineering for this Design fires.

00:31:38.865 --> 00:31:44.285
<v Wojciech Węgrzyński>What a funny problem, what an interesting concept and what a huge challenge for fire safety engineering.

00:31:44.285 --> 00:31:54.377
<v Wojciech Węgrzyński>Perhaps there should be a design fire podcast or something where we would discuss how things burn and what kind of design fire they lead to Maybe a spin-off.

00:31:54.377 --> 00:31:55.660
<v Wojciech Węgrzyński>Maybe I'll do that one day, we'll see.

00:31:55.901 --> 00:32:00.796
<v Wojciech Węgrzyński>Anyway, now let's move to a part that I thought that will be the main part of this episode.

00:32:00.796 --> 00:32:21.323
<v Wojciech Węgrzyński>It kind of ended a smaller chunk at the end and this is what can we assess and how to assess if we have a design fire, if we know for what kind of heat release rate we'll be designing the systems and what kind of fire we will expect at the time when the firefighters come into a building, when they come.

00:32:21.323 --> 00:32:24.420
<v Wojciech Węgrzyński>So you've assessed your timelines and you're fairly comfortable with them.

00:32:24.420 --> 00:32:29.397
<v Wojciech Węgrzyński>Now how do we assess what's happening in the building when they come?

00:32:29.397 --> 00:32:34.709
<v Wojciech Węgrzyński>And this is something that exactly is required by the building code in here.

00:32:34.709 --> 00:32:36.441
<v Wojciech Węgrzyński>So I have to do exactly that.

00:32:36.441 --> 00:32:39.462
<v Wojciech Węgrzyński>I have to assess the conditions in which the firefighters will operate.

00:32:39.462 --> 00:32:40.566
<v Wojciech Węgrzyński>How do I do that?

00:32:40.566 --> 00:32:46.563
<v Wojciech Węgrzyński>Of course I do it by fire modeling, and by fire modeling I mean CFD, and for me it's a simple choice.

00:32:46.563 --> 00:32:56.615
<v Wojciech Węgrzyński>I would just use CFD method as my preferred tool of choice, and I think that's not a very controversial statement, that that's how the fire safety engineering is practiced worldwide today.

00:32:57.135 --> 00:33:05.009
<v Wojciech Węgrzyński>And in CFD you have ability to measure or estimate different variables, conditions that define the environment in the building inside.

00:33:05.009 --> 00:33:16.228
<v Wojciech Węgrzyński>The most basic ones, of course, temperature, radiation, visibility these are the most common variables and probably you will end up working mostly with those.

00:33:16.228 --> 00:33:24.885
<v Wojciech Węgrzyński>So when I look at my fine safety engineering analysis on my simulations, what I'm trying to find in them?

00:33:24.885 --> 00:33:27.738
<v Wojciech Węgrzyński>First of all, what is extent?

00:33:27.738 --> 00:33:30.344
<v Wojciech Węgrzyński>So I'll probably change the way of thinking.

00:33:30.344 --> 00:33:32.448
<v Wojciech Węgrzyński>So there's no easy way to do this.

00:33:32.448 --> 00:33:37.538
<v Wojciech Węgrzyński>There is no easy way that says okay, you know, if the temperature is below 120, we're good.

00:33:37.538 --> 00:33:45.261
<v Wojciech Węgrzyński>Or if the visibility is above 10 meters, we're absolutely fine and the conditions are beautiful and they can just work.

00:33:45.261 --> 00:33:47.125
<v Wojciech Węgrzyński>It's not as easy as that.

00:33:47.125 --> 00:33:55.805
<v Wojciech Węgrzyński>It's not binary, it's a spectrum and therefore it's an assessment and in some buildings some conditions may be okay.

00:33:55.805 --> 00:33:58.429
<v Wojciech Węgrzyński>In some buildings the same conditions may be critically wrong.

00:33:58.429 --> 00:34:11.369
<v Wojciech Węgrzyński>A lot depends on what you are designing and how complicated it is going to be to get to that location and how uncertain you are about the design fire, how uncertain you are about the timeline of the intervention itself.

00:34:11.369 --> 00:34:16.143
<v Wojciech Węgrzyński>All those things will matter in the assessment and what you're looking at.

00:34:16.143 --> 00:34:20.701
<v Wojciech Węgrzyński>For me it's never a simple binary exercise 10 meters, check.

00:34:20.701 --> 00:34:23.246
<v Wojciech Węgrzyński>120 degrees check, we're good.

00:34:23.246 --> 00:34:24.449
<v Wojciech Węgrzyński>It's more than that.

00:34:25.054 --> 00:34:31.686
<v Wojciech Węgrzyński>So I'm trying to look first of all on the extent of smoke in the building.

00:34:31.686 --> 00:34:35.219
<v Wojciech Węgrzyński>So how much of the building is filled with smoke?

00:34:35.219 --> 00:34:38.697
<v Wojciech Węgrzyński>One thing that I'm looking into is the layer behavior.

00:34:38.697 --> 00:34:49.146
<v Wojciech Węgrzyński>So is the smoke in a well-defined upper layer in my compartments or does it fill the entire space of the building from the floor to the ceiling?

00:34:49.146 --> 00:34:52.298
<v Wojciech Węgrzyński>Because those are two completely different conditions.

00:34:52.298 --> 00:35:05.563
<v Wojciech Węgrzyński>If you have a layer, in some cases it doesn't really matter what the visibility in the layer is, because if you're on your knees you can see through the building and you have a really good chance to identify where the fire is.

00:35:05.563 --> 00:35:13.286
<v Wojciech Węgrzyński>Of course, if you have a simple open plan compartment, it's much easier than if you have a labyrinth built in.

00:35:13.286 --> 00:35:22.231
<v Wojciech Węgrzyński>The architectural structure of your building also influences how easily one can define where the fire is and effectively fight it.

00:35:22.231 --> 00:35:37.789
<v Wojciech Węgrzyński>But a layer is something that I look for, and if my systems can maintain this stratification of layers and I can maintain some sort of free layer height, that's a good sign that then I'm already very pleased with the outcome.

00:35:38.375 --> 00:35:42.603
<v Wojciech Węgrzyński>If I cannot, then the visibility will start to matter a little bit.

00:35:42.603 --> 00:35:47.143
<v Wojciech Węgrzyński>A little bit, because I don't find it as a definitive criterion.

00:35:47.143 --> 00:35:54.784
<v Wojciech Węgrzyński>There will be more podcasts on visibility based on the current research that we're doing, so I'll probably go there in those podcast episodes.

00:35:54.784 --> 00:36:04.297
<v Wojciech Węgrzyński>But one thing is like imagine you have 11 visibility and you have a smoke filling your entire compartment, which is, let's say, 1000 square meters.

00:36:04.297 --> 00:36:13.559
<v Wojciech Węgrzyński>Even if I had 11 meter visibility, which would be something that's fine with my tenability criteria, still I can't see anything in that building.

00:36:13.559 --> 00:36:25.362
<v Wojciech Węgrzyński>So it's not really helpful that the tonnability criterion was maintained when the smoke filled the entire space, and also the uncertainties related to this assessment.

00:36:25.362 --> 00:36:29.809
<v Wojciech Węgrzyński>You know the suit yields of materials, the combustion efficiencies and so on.

00:36:29.809 --> 00:36:34.746
<v Wojciech Węgrzyński>So I rather like to look at it whether I had smoked somewhere or not.

00:36:34.746 --> 00:36:40.940
<v Wojciech Węgrzyński>That's the information that I'm rather certain about and the parameters of that smoke.

00:36:40.940 --> 00:36:42.144
<v Wojciech Węgrzyński>That's a challenging one.

00:36:42.556 --> 00:36:46.505
<v Wojciech Węgrzyński>So definitely layer behavior visibility in some conditions I would look into that.

00:36:46.505 --> 00:36:52.228
<v Wojciech Węgrzyński>But really what I'm looking is is there a smoke-free access path?

00:36:52.228 --> 00:36:54.543
<v Wojciech Węgrzyński>That's really a thing that I'm looking for.

00:36:54.543 --> 00:36:56.260
<v Wojciech Węgrzyński>Is there a pathway?

00:36:56.260 --> 00:37:06.063
<v Wojciech Węgrzyński>Because if I design a smoke control system, I would like the smoke control system to work in such a way that it creates a smoke-free access to the compartment.

00:37:06.063 --> 00:37:10.699
<v Wojciech Węgrzyński>That kind of connects the point of access with the fire itself.

00:37:10.699 --> 00:37:16.768
<v Wojciech Węgrzyński>And I like to justify it for myself and perhaps, if I'm wrong, my firefighter friends.

00:37:16.768 --> 00:37:38.295
<v Wojciech Węgrzyński>Please correct me, but I assume that if firefighters have ability to enter a large compartment on fire imagine a car park If they have a good point of entrance and I always make the gates of the car park point of entrance I never allow to extract smoke through the gate point of entrance.

00:37:38.315 --> 00:37:39.719
<v Wojciech Węgrzyński>I never allow to extract smoke through the gate.

00:37:39.719 --> 00:37:49.768
<v Wojciech Węgrzyński>I always use the gate as my main air supply location, because then the firefighters will always have a chance to enter the car park through the external gate, which is the most convenient way to access it.

00:37:49.768 --> 00:37:53.521
<v Wojciech Węgrzyński>So first, is my access point free of smoke?

00:37:53.521 --> 00:37:56.248
<v Wojciech Węgrzyński>If it is, it means they can enter the space.

00:37:56.248 --> 00:38:05.606
<v Wojciech Węgrzyński>Now, if there exists a smoke-free path between the entrance point and the seat of the fire.

00:38:05.606 --> 00:38:11.626
<v Wojciech Węgrzyński>It doesn't have to be directly the fire, but let's say 10, 15 meter perimeter around the fire.

00:38:11.626 --> 00:38:26.621
<v Wojciech Węgrzyński>I assume that firefighters can take a look into the building and immediately see where the smoke or flames are and conveniently approach it and start feeding water, because the discharge distance of water is actually quite large.

00:38:26.621 --> 00:38:28.507
<v Wojciech Węgrzyński>So you can fight fire from 10, 15 meters.

00:38:28.507 --> 00:38:33.875
<v Wojciech Węgrzyński>So I assume if they have this smoke free access, they're very good, in a very good position.

00:38:33.875 --> 00:38:46.503
<v Wojciech Węgrzyński>In some cases it's not really feasible or possible to provide that kind of access and in those buildings we look into the conditions of the smoke through which they will have to move to get to the fire.

00:38:46.503 --> 00:38:50.400
<v Wojciech Węgrzyński>And here we go into those visibility ratings, the temperature of the smoke.

00:38:50.400 --> 00:38:55.099
<v Wojciech Węgrzyński>We like to keep it as low as possible and to give them a chance.

00:38:55.099 --> 00:39:04.221
<v Wojciech Węgrzyński>Of course firefighters can take higher temperatures than your normal people because they are wearing full personal protection systems and those suits are very high quality nowadays.

00:39:04.221 --> 00:39:05.443
<v Wojciech Węgrzyński>They can take a lot actually.

00:39:05.443 --> 00:39:11.304
<v Wojciech Węgrzyński>So we know that they can take a little higher temperatures and radiations than general population.

00:39:11.804 --> 00:39:16.000
<v Wojciech Węgrzyński>The question what is the magic number that you should look for is a difficult one.

00:39:16.000 --> 00:39:17.722
<v Wojciech Węgrzyński>Is it 120 degrees.

00:39:17.722 --> 00:39:19.626
<v Wojciech Węgrzyński>Is it 5 kilowatts per square meter?

00:39:19.626 --> 00:39:21.548
<v Wojciech Węgrzyński>Is it 2.5 kilowatts per square meter?

00:39:21.548 --> 00:39:26.318
<v Wojciech Węgrzyński>I don't feel like I'm in a position to tell you what the value is.

00:39:26.338 --> 00:39:28.543
<v Wojciech Węgrzyński>You probably have to discuss this with the firefighters in your location.

00:39:28.543 --> 00:39:34.239
<v Wojciech Węgrzyński>The authority having jurisdiction so we call it in fire safety engineering that's the person you need to talk about this.

00:39:34.239 --> 00:39:52.867
<v Wojciech Węgrzyński>But we have the numbers that we use and we assume that if those conditions are there, they simply can enter, use some sort of thermal imaging to identify the direction at which the fire is and slowly progress towards that fire.

00:39:52.867 --> 00:39:55.331
<v Wojciech Węgrzyński>Of course it's a completely different progression than if you have a smoke-free access.

00:39:55.331 --> 00:39:56.800
<v Wojciech Węgrzyński>It's completely different conditions, but we just assume that it's a completely different progression than if you have a smoke-free access.

00:39:56.800 --> 00:39:59.731
<v Wojciech Węgrzyński>It's completely different conditions, but we just assume that it's still possible.

00:39:59.731 --> 00:40:23.985
<v Wojciech Węgrzyński>And if the conditions in the car park are extreme, like I have a 400 degrees average temperature of smoke or I see the conditions inside the compartment are promoting a flashover in that compartment or fast growth in that compartment, I just assume I cannot provide anything to firefighters and I have to either change my design fire affect what's in the building or I have to change the systems that I have in my building.

00:40:23.985 --> 00:40:24.985
<v Wojciech Węgrzyński>Perhaps that sprinklers?

00:40:24.985 --> 00:40:27.788
<v Wojciech Węgrzyński>That would be the first and most immediate choice.

00:40:28.148 --> 00:40:30.490
<v Wojciech Węgrzyński>Now let's move to the tools of fire safety engineering.

00:40:30.490 --> 00:40:31.891
<v Wojciech Węgrzyński>I've already mentioned sprinklers.

00:40:31.891 --> 00:40:40.043
<v Wojciech Węgrzyński>I think any type of fixed firefighting system in your building is already the best thing you can have in relation to the firefighting operations.

00:40:40.043 --> 00:40:45.360
<v Wojciech Węgrzyński>Simply, it's best to have your water applied to your fire as soon as possible.

00:40:45.360 --> 00:40:52.521
<v Wojciech Węgrzyński>I think this will universally make the life and job of firefighter easier and by far safer.

00:40:52.521 --> 00:40:55.349
<v Wojciech Węgrzyński>So there's nothing that can be fixed.

00:40:55.349 --> 00:40:58.516
<v Wojciech Węgrzyński>Firefighting systems, whatever kind you are using for sure.

00:40:59.177 --> 00:41:01.802
<v Wojciech Węgrzyński>Smoke control yes One.

00:41:01.802 --> 00:41:04.708
<v Wojciech Węgrzyński>It's going to decrease the temperatures of the smoke.

00:41:04.708 --> 00:41:13.202
<v Wojciech Węgrzyński>It just removes the energy from the building, from the compartment system, therefore limiting the radiation, the hazards related from the temperature to the smoke.

00:41:13.202 --> 00:41:16.320
<v Wojciech Węgrzyński>To some extent it reduces the hazards related to toxicity.

00:41:16.320 --> 00:41:33.188
<v Wojciech Węgrzyński>But keep in mind that the firefighters would be operating in breathing apparatus, so these hazards are not as much directly to them as to your normal population, excluding hydrofluoride, which is a nasty stuff and comes from some of the EV fires.

00:41:33.188 --> 00:41:35.335
<v Wojciech Węgrzyński>So let's say that that's a different story.

00:41:35.335 --> 00:41:42.748
<v Wojciech Węgrzyński>But for most fires the breathing apparatus allows them to proceed, even in the clouds of gases of smoke.

00:41:43.815 --> 00:41:47.206
<v Wojciech Węgrzyński>Smoke control is also capable of providing the smoke-free access.

00:41:47.206 --> 00:41:56.344
<v Wojciech Węgrzyński>And I think in here especially the pressurization systems, the systems that you use on your horizontal pathways, like corridors.

00:41:56.344 --> 00:42:00.503
<v Wojciech Węgrzyński>You can do a lot of those and you can do a lot of engineering with those.

00:42:00.503 --> 00:42:10.590
<v Wojciech Węgrzyński>You can really create great conditions to make sure that the compartment that's on fire, that's the only place in the building where the smoke and fire is.

00:42:10.590 --> 00:42:23.143
<v Wojciech Węgrzyński>The smoke doesn't spread through your corridors, staircases and so on, because if firefighters approach a building, the fire is on the 10th floor and there's already half of the building filled with smoke.

00:42:23.143 --> 00:42:25.824
<v Wojciech Węgrzyński>You have to perform rescue operations, save lives.

00:42:25.824 --> 00:42:35.059
<v Wojciech Węgrzyński>It really makes firefighting extremely challenging, orientation in the building extremely challenging, firefighting extremely challenging, orientation in the building extremely challenging.

00:42:35.059 --> 00:42:42.382
<v Wojciech Węgrzyński>It just makes everything slower and less efficient there than it could be and I believe through my engineering I shall make their life as easy as possible.

00:42:43.065 --> 00:42:44.648
<v Wojciech Węgrzyński>Another thing is information.

00:42:44.648 --> 00:43:14.690
<v Wojciech Węgrzyński>Firefighters need information and if you can design a clever interface that indicates where in the building there is a fire, where in the building there is smoke, which access path is smoke-free, how many people you have in the building, the procedures that are easily outlined, which floor has been evacuated, where do we have places of safety in the building, how this building deals with helping evacuation of disabled population.

00:43:14.690 --> 00:43:34.416
<v Wojciech Węgrzyński>The information is kind of critical because it also will make decision making on the site easier for firefighters and I'm a huge supporter of visual aid systems that have a map of the building that just show you, you know, with LED diode, here is the location of the fire, you are located here.

00:43:34.416 --> 00:43:43.985
<v Wojciech Węgrzyński>It really makes life easier if you can communicate such an information and I don't think enough value is placed on systems like that in fire safety engineering.

00:43:43.985 --> 00:43:54.309
<v Wojciech Węgrzyński>I think those information systems are perhaps as important as active means to suppress the fire or extract smoke and heat from the building.

00:43:55.315 --> 00:44:00.807
<v Wojciech Węgrzyński>Earlier I've mentioned fire alarm systems and automated alarm transmission devices.

00:44:00.807 --> 00:44:02.300
<v Wojciech Węgrzyński>For me it's kind of prerequisite.

00:44:02.300 --> 00:44:14.960
<v Wojciech Węgrzyński>I don't really do fire engineering in buildings that do not have them because we're typically involved in large buildings, but definitely if this is something your building does not have, it will make this transition into firefighting easier.

00:44:14.960 --> 00:44:19.606
<v Wojciech Węgrzyński>It will just help issuing signal to firefighters that there's a fire in your building.

00:44:19.606 --> 00:44:20.708
<v Wojciech Węgrzyński>It will shorten the timeline.

00:44:20.708 --> 00:44:34.356
<v Wojciech Węgrzyński>So definitely a very important system lifts and lifts for firefighters.

00:44:34.356 --> 00:44:35.780
<v Wojciech Węgrzyński>So vertical transport of heavy equipment is extremely difficult.

00:44:35.780 --> 00:44:42.719
<v Wojciech Węgrzyński>If we can provide them with lifts that are safe in case of a fire, that are at a higher degree of safety that they can trust.

00:44:42.719 --> 00:44:45.746
<v Wojciech Węgrzyński>I think those could be great things.

00:44:46.306 --> 00:44:47.108
<v Wojciech Węgrzyński>I've mentioned trust.

00:44:47.108 --> 00:44:50.257
<v Wojciech Węgrzyński>This is an important one Really.

00:44:50.257 --> 00:44:54.219
<v Wojciech Węgrzyński>Whatever system you're designing, the firefighters have to trust it.

00:44:54.219 --> 00:45:04.523
<v Wojciech Węgrzyński>I've had those discussions with firefighters where I was designing a very complicated smoke control strategy that, in my eyes, was beautiful for the building.

00:45:04.523 --> 00:45:08.025
<v Wojciech Węgrzyński>It's really great.

00:45:08.025 --> 00:45:12.867
<v Wojciech Węgrzyński>But the first thing that I will do when I arrive, I'm going to turn this off.

00:45:12.867 --> 00:45:14.188
<v Wojciech Węgrzyński>I do not trust this.

00:45:14.188 --> 00:45:19.871
<v Wojciech Węgrzyński>I do not understand this and I do not trust this with my life and this was like a red light for me.

00:45:19.871 --> 00:45:22.413
<v Wojciech Węgrzyński>I cannot make my systems too complicated.

00:45:22.413 --> 00:45:35.514
<v Wojciech Węgrzyński>I need to make systems that can be understood by firefighters and that they can use to their own benefit, because they will also take actions in the building.

00:45:37.755 --> 00:45:42.347
<v Wojciech Węgrzyński>If you think about smoke control, smoke control works in a very well-defined set of boundary conditions inlets, outlets you know what the flow path is.

00:45:42.347 --> 00:45:49.715
<v Wojciech Węgrzyński>But if they put, let's say, smoke curtain in an inlet that you consider your makeup air inlet, they're going to change everything.

00:45:49.715 --> 00:45:55.126
<v Wojciech Węgrzyński>If they use positive pressure ventilation outside of your building, they can change the flow path.

00:45:55.126 --> 00:46:05.927
<v Wojciech Węgrzyński>They will affect how your systems work and the better they understand the systems, the less chance is that the final outcome of your system working and their intervention.

00:46:05.927 --> 00:46:08.677
<v Wojciech Węgrzyński>There's less chance of failure in that case.

00:46:08.677 --> 00:46:18.786
<v Wojciech Węgrzyński>Therefore, I think making systems easy to understand and obvious in how they operate and trustworthy is a key component in here.

00:46:19.568 --> 00:46:26.804
<v Wojciech Węgrzyński>And finally, a big factor is architectural complexity, and it's something you can also think about when designing buildings.

00:46:26.804 --> 00:46:31.300
<v Wojciech Węgrzyński>What are the view paths from the points of entry?

00:46:31.300 --> 00:46:36.182
<v Wojciech Węgrzyński>How much you can see from the point you enter a compartment or a floor?

00:46:36.182 --> 00:46:40.405
<v Wojciech Węgrzyński>Is it easy to navigate that floor or is it very difficult?

00:46:40.405 --> 00:46:50.360
<v Wojciech Węgrzyński>Is it possible to just enter a floor and immediately see all ends of it, therefore making identification of the location of the fire easier, or is it a labyrinth?

00:46:50.360 --> 00:46:52.981
<v Wojciech Węgrzyński>You can't just go above that.

00:46:52.981 --> 00:46:56.219
<v Wojciech Węgrzyński>It has to be part of your considerations.

00:46:56.219 --> 00:47:13.409
<v Wojciech Węgrzyński>You have to account for that, and any good fire strategy or any good fire safety engineering analysis must be aware that different architectural complexities will lead to different firefighting operational procedures and, different times, different timeline of operation.

00:47:13.409 --> 00:47:15.902
<v Wojciech Węgrzyński>I think a good fire safety engineer should consider that.

00:47:15.902 --> 00:47:30.923
<v Wojciech Węgrzyński>One challenge is that we sometimes, for example, office buildings, we often would do fire safety engineering for shell and core design and then when a tenant comes there, they would come with tenant design, which would be completely different thing.

00:47:30.923 --> 00:47:41.809
<v Wojciech Węgrzyński>So for shell and core, I just provide means that someone eventually the tenant can design with those means a system that will work for them.

00:47:41.809 --> 00:47:50.641
<v Wojciech Węgrzyński>It's probably challenging to account for firefighting means when you have a shell in core stage, but but still I think it's.

00:47:50.922 --> 00:48:02.137
<v Wojciech Węgrzyński>Anyway, this was a lot of talking about how we account firefighters and I think one thing that you can notice in this episode is how insecure I am about this.

00:48:02.137 --> 00:48:04.742
<v Wojciech Węgrzyński>It's kind of really uncomfortable.

00:48:04.742 --> 00:48:07.668
<v Wojciech Węgrzyński>I like to think about myself as an expert.

00:48:07.668 --> 00:48:10.382
<v Wojciech Węgrzyński>I've designed a few hundred buildings like probably like 500 of them, and in each of them.

00:48:10.382 --> 00:48:15.034
<v Wojciech Węgrzyński>I've designed a few hundred buildings probably like 500 of them, and in each of them I've considered the fire safety operations of firefighters.

00:48:15.034 --> 00:48:38.559
<v Wojciech Węgrzyński>Therefore, it's something that I routinely do every day, but I do it because I have to, and every time I'm doing it I remind myself I'm not a firefighter, and one thing that really helps me doing this job is talking to firefighters, having firefighters included in the design and seeing what their expectations are.

00:48:38.559 --> 00:48:45.304
<v Wojciech Węgrzyński>I would not say it's possible on every single project, but when you design a tunnel, when you design an airport.

00:48:45.605 --> 00:48:56.411
<v Wojciech Węgrzyński>It's very easy to reach out to them and they are very interested in participating in those discussions and they can tell you exactly what you want to know, and you may be surprised with the things they want.

00:48:56.411 --> 00:49:00.726
<v Wojciech Węgrzyński>You would think they want smoke control, but no, they may want better water supply.

00:49:00.726 --> 00:49:05.378
<v Wojciech Węgrzyński>They may want a better hydro network or more access points to water.

00:49:05.378 --> 00:49:14.021
<v Wojciech Węgrzyński>They may want a safe space in which they can rest and, you know, reorganize their safety operations at the 20th floor of your building.

00:49:14.021 --> 00:49:22.826
<v Wojciech Węgrzyński>They may want a space where they can change their oxygen bottles or a sort of a system that will automatically change them.

00:49:22.826 --> 00:49:32.418
<v Wojciech Węgrzyński>These are the things that they often want and, as a fire safety engineer, you probably would not consider them up to a point when you are forced to do that.

00:49:32.418 --> 00:49:41.610
<v Wojciech Węgrzyński>They may want communication systems in place, better radio antennas in your building to support their radio communication.

00:49:41.610 --> 00:49:53.914
<v Wojciech Węgrzyński>Those are things that you would not think as a fire safety engineer until you talked with firefighters, which I highly advise you If you want to design your building to support firefighters.

00:49:54.614 --> 00:50:30.320
<v Wojciech Węgrzyński>Firefighters are the people you should talk with to assess what they need and I'm pretty sure as soon as it's clear what their expectations are, and as soon as you clarify some key components of your designer, such as the timeline, the design, fire, and so on, your designer, such as the timeline, the design, fire, and so on you will be able to create a building for which you will be able to say yes, I have accounted for firefighting operations in this building in my engineering design and that's how I would like to conclude all my engineering and this is how I would like to conclude this episode.

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<v Wojciech Węgrzyński>I hope you will have a good time designing buildings.

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<v Wojciech Węgrzyński>I hope you will be able to design fire-safe buildings and you will be able to account for the needs of firefighters.

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<v Wojciech Węgrzyński>They are awesome people.

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<v Wojciech Węgrzyński>They are people willing to risk their lives to save others.

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<v Wojciech Węgrzyński>I have the greatest appreciation to the firefighters and I would simply like my engineering to be useful to them.

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<v Wojciech Węgrzyński>Thank you very much for listening to this Fire Science Show episode and I hope to see you here again next Wednesday.

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<v Wojciech Węgrzyński>Thank you.