QA#1 - November 2022

Hello, everybody. Welcome to the Fire Science Show. Today, we're going to do the first in history of the podcast session of questions and answers. Very happy to do that. So, as you've noticed on the webpage of the podcast, there's a button to send voicemail and you can use that to send me, um, voicemail with a question or comment or your point of view that can be shared in the podcast, which I will happily do in sessions. Just like this one. Uh, or you can just send me an email through the contact form or directly. Can always reach me at wojciech@firescienceshow.com. And I'm very happy to include your views and opinions and questions. And this type of episodes, I hope this allows us to build a better relation and a. I mean, I'm usually the one who's asking the questions in here. And, uh, this time it's only in your hands, you have a chance to ask the questions. I will try to answer them on my own. If I feel I'm not best suited to answer his question, I'm going to try to reach a former podcast guest. To find an answer for you and, We'll see how it gives. So yeah, let's start the first Q and a. okay, so, uh, for the first question for today's q a, I brought, guests, man of the podcasts of, October hi Piotr nice to have you back. hello our local ITB expert on fire resistance. And as the question is on fire resistance, I couldn't resist to, to bring Piotr back. Uh, the question comes from Millie Wan and she's asking about, Fire resistance testing. The question is, in Australia, our fire resistance test methods tests the floor and will assembly separately in order to assign a fire resistance to each element. Recently, the building certifiers have been asking questions about the likely fire resistance at interfaces. Uh, what's the likely impact of on the fire resistance level, at the corner fire that can affect both the floor beam and the steel combs within the fire related wall? I understand that the. Fire test set is not set up for this at all. Is there an inherent point of failure at this interfaces? I think that's quite interesting question about going out from just testing a single element to more like a full frame performance of the building, but Piotr please if you can answer about the fire resistance of interfaces and how our testing methods cover that floor is yours.

So as it happened, I actually have some experience with the Australian standard. I've seen that, uh, as 1504 standard and, let's say it's a very, very limited version of what we do in Europe. So, Indeed, there is absolutely no part of, that testing standard about linear joint fields in Europe. We have a specific standard for, for that test particularly, and this is the e N 1366, part four. So, answer the question, If it's a connection between walls, and floors, or between floors or between walls themselves, this standard is, absolutely meant for, the assessment of fire resistance of that connection of that linear joint. And there is a number of, options that you can test and number of, results that you will then be able to address. Including

So

movement without movement, like linear joint seals made on site or at the factory. the testing of slices, the interface between each part of these, joints of these seals in those joints. Uh, so for walls and floors, there is a standard and we do this test on a daily basis. and that's your, that's your way to go.

and it includes the joint. It, it's, it tells you about the fire resistance of the joint, right?

Yes, it tells you about the resistance of the joint and you have to, and, and your supporting construction, which is your floor and your wall are standardized. so then you have some field of application of your test results depending on, what construction, uh, type that you've used. But, some general information may be also drawn from the test of a wall itself, because its supporting structure also contains, uh, fixed edges. And one of them is, uh, fixed edge to the lintel. And this lintel is, simulating, reinforced concrete floor, for example.

supporting structure? You mean the, framework? You put the testing element when you place it on the furnace.

Exactly. yeah. yeah. that made the, the also types of, supporting constructions that you may use and they will also give you some information. But The specific standard for these joints between walls and floors, or between floors and floors and walls, and walls that are all types of connections. The T joint, the V joint, age, joint, and so on. This is the e N 66 part four that you want to go for. And as the standard, uh, has been refreshed, uh, not so long ago, it's, uh, almost 60 pages long, it contains quite a number of details. I won't go into them, but, uh, that's the way to go.

sorry, I'm gonna steal Millie's question, and to turn into my own, uh, how do you feel about testing these joints and connections in. um, full scale natural fire experiments? Because we, we happen to, to, to do a lot of them at ITB recently, Erecting a frame of a building or a part of the building, uh, making a natural, let's say, office fire. Inside of that, and in every of these tests, we, we had clients, who asked us to, to do additional measurements at the edges at the connections. you think this can give a reasonable information about the performance of such a joint in a fire or you would rather test it on a furnace based on the you just mention.

Uh, generally I am a big fan of testing, uh, more complex structures rather than isolated elements. very often we'll see, for example, for floors whe where they have combustible infields that will get fire at the free edge. And that's a problem because it wouldn't normally occur over there. when we test some modular, containers or stuff like that, the corners, the joints are absolutely necessary to be tested as well, because they do provide load bearing capacity to the elements. They do provide additional installation and they create natural. fire exposure conditions rather than insulating the, the elements themselves and testing them separately. As for the testing, on fairness versus natural test, well, I, it is like it is for, for any test. I mean, natural test, like with a more complex structure with, Fire load rather than burners, acting, uh, as, as the fire load, this generates a completely different environment for the test specimen and the its behavior, may be very different from the one on the furnace may be more representative to, to reality team. Uh, but what I would like to the takeout of my, uh, my opinion be is that we should, as much as we can include tho those details in every test, whether it's on furnace or whether it's, uh, real fire. And also answering the second part of the, of the question from Millie about the connection between, elements like beams and columns, especially made of steel, as they will usually require some fire protection. the approach, uh, in the standard is that you do not test these connections. I mean, they are, uh, represented a bit

Hmm.

to not go into much of a detail, but it'll say if you test intermission coatings, you get these steel plates at the top of the, of the short. I dissects to short, I dissect columns to represen. A possible connection to a beam where you also put some fire protection, but otherwise, that are not present. You test isolated elements. And I think that the reason for this is similar to the one given in neuro code three that we also used to assess steel, structures in fire. And the idea is that at the connections you will most likely get more mass or more steel than on a, on a singular element. And when you get more mass, your section factor gets lower. The heating conditions are so that the temperature should be lowered than at the, uh, span of the element, let's say. So. Until your fire protection is continuous, uh, there are no gaps and you, you fire, protect everything including bolts, uh, and welds and so on. Uh, the, the additional amount of steel of mass will give you the benefit of lower temperature. So if the, if the connections are designed properly, by which I mean that they're stronger than the elements themselves. Uh, there shouldn't be any problem over there. but you have to keep the fire protection continues, in those places.

And, as you know very well, people hate, , doing, furnace tests because of the cost involved and, and complexities and stuff like that. Any in a way to, test joints at a smaller scale. I Also thinking about, you know, multiple joints within one test or maybe there, there's, a simpler method, uh, that can unravel the the behavior of such joint or maybe numerical method modeling is, is a way what, what do.

I'm thinking that testing multiple joints is like a revenge of the customer over the lab because, the, the standard allows for multiple joints in one test. And I've seen some tests with, I dunno, countless connections, countless joints, like 400, 600 thermo couples at once, like, like a nightmare. So yeah, there's, there's definitely a. to improve the cost result ratio, let's say, Uh, definitely possible and definitely allowed in the standard, even for the connections between walls and floors. Uh, I remember some of my own tests where I've had like 13 types of connections that tested at once. Definitely you can improve the cost. Uh,

that's takeaway from the clients. the clients, If you if you you want to take revenge us give us this extreme extremely expensive test to do, and we extremely unhappy, unpleasant with, doing this, this for you. And, Piotr thank you very much for this comprehensive, answer. Anyone who wants to more about connections. were very welcome to come here and. here and, And burn down a joint with me in p

Thank you very much Wojciech for having me again and uh, good luck to everyone.

man. Bye. Okay. I hope that answers your question. Millie quite dwell. And if you need more, You can always reach. Piotr And he's going to tell you more about fire resistance of joints. I mean, he can talk about fire resistance. Four hours. I don't want this. At business to be too long. now let's move to the second question. asked by Elena Funk She's been a longtime friend of the show and she's Actively encouraged me a year ago, which I appreciate a lot. It helped me do some fun stuff in, in the podcast. And now Elena is researching carparks and she's been asking me. About the Polish experiences with smoke detection. And Car parks she's wondering how smoke detection is carried over the world. And I think it's a brilliant question to ask. Actually now I realized that we, I think almost not at all Spoken about, smoke detection. We did touch the bit. In the space episodes. But, uh, I don't know if that counts. So I must say sometime ago when we were hosting a SFPE um, PBD conference also. I've met some people from Australia and they wondered how we do. Smoke controlling car box and I've told him we often use. jetfan system. Ventilation in car parks and they were very intrigued and, but they were cute. Kept asking like how the jet funds know when to start. How, how do they know when to operate? And I didn't know how to answer that question because for me it seems quite odd to ask about it. And eventually I told him, yeah, I mean, is that, isn't that obvious? The smoke detection, that's the detects the fire. And then they just go and they were like, whoa. So shocked. You have smoke detection in car parks. Then I realized it's a. It might be a cultural thing or local thing. To, to have a certain systems. In your buildings and, in my country, And for all the car parks above 1500 square meters, we do have smoke detection in them. So pretty much all larger carparks are equipped with smoke detection. And I think it's critical to have that type of a system. One that you want to, the fire brigades to come as early as possible to your car park. I mean, you have 15, maybe 20 minutes to react. Before the fire can spiral out of control. Of course that can happen earlier. But, but the typical growth of the fire in the car park, it will take some time to build up. So, so Early access for firefighters early information. Firefighters may be actually critical. In in stopping the fire. A second thing is. The car parks are not always full of people. I mean, that's a good thing from life safety perspective, I guess. But if the fire happens at 5:00 AM on their residential building, it may take a really long time to notice it. And this is a case we had in Poland, which led to a very devastating fire. I have a car park exactly in the residential building. So I think the early detection and detection at all. Is is very helpful in, in fire safety. Of carparks now in terms of how we detect the fires. That's a tricky one. I think in Poland, the most common would be a multi detector sensors, some sort of heat and smoke detectors, or maybe CO and smoke detectors or, or triple censored ones. They are very good in keeping the false alarms away. Because in car parks you're going to have some fumes after all. I mean, it's, it's a carpark so we would use these, these types of sensors. Uh, very rarely it would be just purely a smoke, optical detectors. And I don't think I've ever seen one just on heat detectors. I don't think that would work very well in the car park. So I'm definitely there, there. choice of devices to be used cinder. Uh, one interesting thing in, in many car parks in Poland, we also have the LPG gas detection systems. That's also something I'm not sure how commonly stat in your countries, but in Poland. LPG vehicles are very, very popular and you have this separate sets of gas detectors. At the floor of your building, because RPGs is more dense than air. Uh, scattered around the car park. And they also trigger operation of the smoke control system. It's usually triggered at the sanitary remote, not necessarily the fire mode. But it can also trigger the fire mode without issuing a fire alarm. So, um, yeah, a separate set of devices that also control the operation of the. Systems in, in, in your car park. I hope that answers your question. To a degree. I'm not an expert in fire detection. I guess I should find one and then get an episode about how smoke sounds. work because I knew many scientists have actually no clue how smoke detectors work. And that's a, that's a fascinating part of the fire. Science after all. So Elena thank you very much for your question. And now we jump into question number three. This third question is, is very interesting. It touches the architecture and fire safety. It was sent by a listener Ekponudim friday and yeah, I'm here. The podcast is yours.

Yeah, we like to ask how do we balance aesthetics, design in terms of architectural buildings with fire load? Because I understand recently you see people, the build so many materials, especially wooden materials, easy to interior decoration of building. Considering the fire load in that building, it's really high. So how do we balance aesthetics and and

Okay, I'm going to try to take these on my own. If I fail, let me know on the find someone better. so early in my career days, I. Have figured out that we cannot really change the way how architects build buildings. And, beauty is a function of a building. I mean, Even in de architectura era from Roman times. I think the first piece of literature on building engineering, it was already defined it. The beauty is one of the functions of the building. And I feel that truly EAs. I mean buildings and their aesthetics are a super important, I was raised, you know, in a communist blocks uh, every building in the, my. Half kilometer proximity looked the same and there were all equally horrible, not a very pleasant view. Then I moved war. So it's much better in here now as the city. is, is growing, is getting beautiful. There's so much beautiful architecture around and that I really enjoy that. It just feel better. It feels better to leave in a beautiful. Uh, space. So I think beauty is an important function of the building. Really, really an important one, not something we should, cancel or play down when designing our stuff. We're fire engineers. We should design with whatever comes our way. Here, I think an interesting episode to listen to is episode 15 with Benjamin Ralph who is working with an architect bureau and a. That's his bread and butter. How to define fire safety in a Ethically pleasing buildings. So definitely take a listen to that one. Now in terms of, your work as fire safety engineer first, I think the most important thing. In balancing beauty and fire safety is actually trying to do that. I mean, having fire safety engineer. Involved as early in the project as possible, where the most fundamental decisions are being taken. This is the first guarantee that. fire safety and aesthetics will not have to compete between each other. But, uh, as tactics can be achieved. While maintaining fire safety. So first thing. Get the fire safety engineer on the project early, because that will help you make informed decisions on the materials on the settings. On, uh, the, the shape of the building that promotes fire safety. Second thing is, you can, design, fire, safe buildings with, let's say not to fire safest materials. It's all about how much and where you placed him. I think a great example is with timber compartments, everyone would like to have all walls and ceilings exposed, but, do we really need that may be a aesthetics can be filled with just having the ceiling exposed, for example, and, the walls, uh, protected with fireboats, which tremendously changes the fire behavior of the whole compartment. That's just one example. Another example is, is I always liked to build larger, like bigger spaces, promote fire safety. They. Change the, the fire dynamics in your compartment in larger buildings, larger volumes, you can provide more safety. So sometimes you can maybe come to measure some choices with, with more space or maybe with active systems like sprinklers, water, mist. Smoke control. There are solutions that are low you to take into account that someone wants to. Do something in a very specific way, maybe because of the aesthetics. And you can find a solution that, covers that gap in the fire safety of your building by proposing an alternative scenario, alternative solution, additional means of protection. Or maybe simple choices. Of course. You also want to block decisions that inherently lead to very dangerous solutions. And then there, that is where fire engineers should come in and say, okay, this combination of materials is absolutely dreadful. I have blocked some stuff like that. I remember a tunnel tramway tunnel, where they wanted to line the tunnel walls with, HPL boards you know, the ones that we know from facades that burned quite vigorous, even though they are. can be done in class C or class B quite high, but in very specific arrangements doesn't matter that much. So. A very aesthetically pleasing material, but from my opinion, quite a dangerous one I've told them that I've explained them why they have made some smart. Changes replaced them with some sort of A2 boards that look very similar. And we have both. We have beauty, we have the fire safety in the building, so we have. It's definitely achievable, not easy to buy. I don't have a one single equation for safety and, and beauty birds. I really think beauty is an important objective. And I really think the role of fire engineer is to make that happen in the building. The fourth question came from a listener from Iran. Neda well, Neda that the floor is yours.

Hi. I am Neda an Assistant Professor of Fire, department of Road Housing in Urban Development Research Center of Iran. In Iran we do not have fire engineering as a course in our universities. All we have related to fire and buildings is the fire department of R U H D, which I am working in. So you can imagine the situation in which I am, I have to be familiar to different aspects of fire behavior in buildings to develop codes, guidelines, and regulations. For near 90 million people's buildings, and all I know about fire is my self studies. So I really appreciate your efforts in producing such an advantages show. thanks for your good podcast. And, I want to ask you to provide a written version of Fire Science show, like fire paper or something like that, because sometimes I need to refer to one of the shows and I cannot, it's not written, thanks.

Well, first of all, I'm hugely thankful for your kind words about the podcast. And I'm delighted that it's a way for you to find. Knowledge about fire safety. So first let me refer on building your, your conscious fire safety. I think that's an enormously responsible job that you have, and. While providing. Uh, fire safety, the whole country. Having ability to actually affect that. It's something that many of us dream of in our countries. I'm not sure if we really would like to have that. Sort of obligation or, or possibilities in here. it must be very, very tough. As you mentioned. If I had the blank page to build fire safety for my nation. I think the first step that I would take would be to, uh, Just speak of a. Prescriptive. Code model code. And build something around it. Maybe something like IBC, the international building code. Though I understand that that political constraints may be here against you because that's something that origin needs from us. Um, I guess many listeners would go crazy. Like Wojciech what do you mean? Take a prescriptive code and employers you where you are the chosen one. You were meant to stop them, not join them. I agree, but. In the end. if you are in the country where there is not that great fire safety education, as Neda mentioned, she is struggling to find resources. I highly doubt. There is a lot of skilled fire safety engineers in the country. Going performance based design way. It could be a recipe for disaster. And, and prescriptive codes have a history of providing fire safety worldwide. So I guess that would be a good starting point because. Uh, model code, try to implement it with modifications That are reasonable for your local requirements, local. engineering practices and execute that. And eventually tried to find a way to put more performance-based engineering in, in the mix of the, of the low and Seaway where you gather with that. I think that would be the. The safest bet. At the place where you are. It's difficult. Uh, and, but definitely. You have a lot of space for creative work. And I really wished that, uh, you find a way to, to, to provide this fire safety to your country. If you do, please let me know. I would love to talk about that. The second question you've asked is how to cite the podcast how to refer to the fire shows. So. At this point, every episode is transcribed, which means there's a written version of it in the, in the episode, webpage. These transcriptions are not perfect because they are done by AI. Uh, the AI is, is improving, but it still has some silly mistakes in it. Please forgive me that, but it's an enormous amount of work to, to transcriber. I've spoken podcast episodes to written form. I'm not really sure if you should refer to them though. Keep in mind. It's it's a podcast. I mean, I try to be as objective as I can. And I bring guests that in my own opinion, there are world-class specialists in what they're talking about. However, it's not peer reviewed. It's. Inevitably biased. In some ways I cannot guarantee that, uh, what we say here is an objective through the event, the thing like that exists. even in, in science, there are opinions and, that's why, why we have peer reviewed science in the first place. So I'm not sure if I would like to refer the most important decisions to what you've heard on the podcast. Now a good idea is that most of my guests come here to talk about the research. Uh, about things they did in the past. And most of these things are published in very well established peer reviewed journals. And I try to link to these pieces of work. In the show notes. If I don't please reach out to me or reach out to my guest. We will be super happy to direct you. To a citable source. That's very credible, unbiased peer reviewed. Which you can definitely use in your work. And I think that would be that the best way. To, to cite the podcast. Through the work that has been talked over in here. I hope that that helps you and add all the best in, in building fire safety in Iran. And the final question of today comes from Szymek Matkowski. Szymek is an architect he's, uh, in his free time. He's designing space habitats in Nexus, Aurora project. And you can imagine before the. Uh, space episode, he sends me like 20 questions. To ask To Dr. Urban from NASA. I've used some of them. Thank you, Szymek was very helpful. To see what's interesting, the habitat community, and I hope I've managed to ask some important things online that that help me design. Your projects now onto your question, You have asked me about boutique shops in shopping malls. Referring through in the episode that they did about the smoke control from malls and what drives the smoke control and how can we design it better? Uh, your question is too formal. First, you ask. Why don't we just connect the smoke reserve was above a multiple smaller shops to create one large smoke reserve war and exhausts from that. And the second one, this is why I would like to have the smoke in the mall in the first place. When there are people when there's evacuation taking place. from the mall itself, both are great questions. So, let me start with the first one. Um, connecting with Deeks. It's technically possible. And if you, if you can do that and have a joint smoke control system. That extracts the smoke from all of them all together. That probably is very, very good strategy, especially that you most likely will have quite tall. Compartment, which makes, uh, extracting smoke easier and more efficient. So if you can do that, that. Then probably that's, that's a great way to go. However, I always found troubles, merging them. First of all, because of the acoustics. These shops tends to like, to torture people inside with their own music and, all communicates it. Sometimes due to acoustics in general, we, we had to compartmentalize the shopping malls into smaller units. So it was not technically possible to merge them above the false ceilings. Second thing would be something as. Protection of the property. Or just separating them so they can be sold as separate units. So I think the limitations come from outside the fire safety world. I never could really merge this, uh, shopping. Things easy. If in your system, wherever you work, it is possible. I guess that's a, that's a very decent strategy and the the bigger, the joint. Uh, compartment as long as it's not crazy large, but. It's very hard to do to extract smoke from something that's just hundreds of 200 square meters. If you can merge five or six of, of compartments like that into one larger one. It's certainly easier to extract the smoke from, from The second part. Why do I want to have smoke in my mall? Why not? Just from the shop. Well, it is very difficult to extract a large amount of smoke from small shopping. Uh, You need, you would need quite large. Um, exhaust exhaust rates in that shop to succeed. Talking about 50, 60, 70,000 cubic meters per hour. shopping unit. Sometimes it's impossible to create docs that lodge. And successfully extract for a super, super small space. In contrary, the mall is quite safe space. Even if you have smoke in it. I mean the smoke. Um, because of wounds, it will go up and usually the mall is, is quite a large space. You have a giant small reservoir in it and you can extract quite efficiently from it. So when we were designing extraction from malls, from common malls in shopping malls, We've very rarely reached a scenario in which in a single shop fire. We would ever have smoke at the height of evacuation. We always kept it a boat that that was our design objective. And we kept the it above not just for the evacuation time, but usually we kept it above the evacuation pathways infinitely as the fire reached some steady state size. We were just extracting the smoke as se. Entered the mall reserve war. And did that layer never Declined to the level where people are. So I'd say. If you can design a system like that, it's neutral to the fire safety of the mall. So you still have a space that is viable for evacuation. You still have a space that's viable for firefighters to enter and do their jobs. And at the same time you have space from which extracting this smoke is, um, very easy. I think I would call it a very cost-effective solution. Definitely easier to put two, three large fans in the mall on the roof, somewhere with very short ducts with direct exhaust to the atmosphere. Rather than making complicated smoke control system, connecting to the individual shopping units. With the mass of dampers that we'll need to open and close depending on where the fire is. I mean, the alternative is very, very complicated and expensive system. And in the end, if you design it well, If the exits of the shops are large enough tall enough. You really can reach the level of safety. Same as if the boutique shops were individually extracted. So, yeah. Cost effective. solution that doesn't, hindered the safety of the mall. If, um, someone has a different opinion, I would love to hear it. I would love to learn how you do shopping malls in your countries. The way, how I did it in Poland, the way how I investigated it. And it, my PhD is, is just like I said, and from my experience that worked, that worked well. So we are sticking to that, I guess. And that's all of it. Uh, five questions asked and answered on the first question and answers episode of the fire science show. I hope it went well. And you've enjoyed that. Thank you very much for all the people who sent their questions. It was a huge joy to work with them and try and answer them. And I'm looking forward to more questions asked. As said, as mentioned in the beginning of the episode, there's a sense voicemail button on the webpage through which you can send me. Your prerecorded question and I'm going to play it in here. Like you've heard. In some of them, you can also send me an email and I will just read it out and try and answer. If I cannot, I'm going to find the guests to can, And no matter what I'm going to try and find you. And answer to a problem that you have, and I'm super curious of your opinions or. Maybe you do something different, like I'm really, really interested. If someone is doing something in fire safety. That is completely different than how I discuss it in here. Like with the detection in car parks it's so fascinating. I do find differences in the world that come from the culture from engineering, from the local low, from maybe just a fire that happened 50 years ago in your particular country. And it changed everything in that country. It's super interesting to find it out and I'm very, very happy. Uh, To do that. So, yeah. Looking forward to more of your questions and comments. One thing before we end. There is also the listener experience survey going on. You can find the links are on my social pages. You can find the link in the show notes to this episode. Or you can find it in the newsletter. If you signed up for the newsletter. And the listener survey is about you. It's about finding what you like about the show, what you don't like about the show, how the show can be improved. I really want to make this. The best experience possible for all of you. So please share your opinions with me. I, I trust them. I, uh, I will do my best to, to move the show into the direction that reflects your. Overall opinions about, how it gives so far. So, yeah, I am an engineer. I like to take informed decisions. I need information. Please give me it in the, in the Google forums. That's it for day today's Q and a one. Thank you very much for being here with me. And the podcast is back on Wednesday, two days from now. So, ah, see you soon, friend. Cheers.