151 - Elevator evacuation with Axel Mossberg

Elevator Evacuation in Fire Safety

Speaker 1 0:01

Hello and welcome to the Fire Science Show . You should not evacuate with elevators . I guess you know that . I guess you've learned that it's kind of engraved in the mind of every fire safety engineer . But my question is why ? Why cannot we evacuate with elevators ? What would happen if we could ? Would it be better , would it be worse ? Is it really hazardous , is it not ? What challenges are we could ? Would it be better , would it be worse ? Is it really hazardous , is it not ? What challenges are we in ? There's a ton of questions that appear once you start thinking about the paradigm that exists that you should not use them , and start to think what would happen if we broke that . And for that , of course , I have a podcast guest today , dr Axel Mossberg was kind enough to share with me his insights from his PhD on the behavioral aspects of use of evacuation elevators in buildings .

Speaker 1 0:50

I'll tell you how we came to this episode . I wanted actually an episode about using virtual reality in experiments on human evacuation , because Axel has done that in his PhD thesis . And when we were talking about the Vier experiments and the elevator case study , what was the case study used in that PhD ? I was just fascinated about the way how he was describing the use of elevators , the rationale behind using elevators in evacuation , what you could get with them , and I thought no , I have to do an elevator episode . You guys are gonna love it , so I hope I'm not wrong . I'm sure I'm not wrong . You will enjoy this episode . It gives a very fresh and interesting uh insight into a very important subject evacuation in a different way than we do it always , and perhaps you should see for yourself if the elevators are dangerous spaces or perhaps we can use them to bring safety to our buildings . So let's spin the intro and jump into the episode .

Speaker 1 2:00

Welcome to the Firesize Show . My name is Wojciech Wigrzyński and I will be your host . This podcast is brought to you in collaboration with OFR Consultants . Ofr is the UK's leading fire risk consultancy . Its globally established team has developed a reputation for preeminent fire engineering expertise , with colleagues working across the world to help protect people , property and environment . Established in the UK in 2016 as a startup business of two highly experienced fire engineering consultants , the business has grown phenomenally in just seven years , with offices across the country in seven locations , from Edinburgh to Bath , and now employing more than 100 professionals . Colleagues are on a mission to continually explore the challenges that fire creates for clients and society , applying the best research , experience and diligence for effective , tailored fire safety solutions . In 2024 , ofr will grow its team once more and is always keen to hear from industry professionals who would like to collaborate on fire safety futures . This year , get in touch at OFRConsultantscom .

Speaker 1 3:20

Hello everybody , I'm here today with Dr Axel Mosberg from Pendelgren , brandon Ryska from Sweden . Hey , axel , good to have you in the show . Hi , thanks for having me . It's nice to have you and you have done your PhD on an extremely interesting subject to me , which is elevator evacuation and being a topic that's very under-researched in fire and definitely the elevators are underused as a tool for fire safety and most of my listenership comes from the UK and you know guys there have this crazy battle whether we put two staircases in the building or do we put one , and I jump in , you know , from the side . And how about an elevator ? And let's try and figure out what's up with the emergency elevators in the fire safety engineering world . You happy with that , yeah ?

Speaker 2 4:09

sure Sounds like right up my alley .

Speaker 1 4:13

Fantastic Vertical alley .

Speaker 2 4:16

Anyway .

Speaker 1 4:16

Axel , you know the first thing when I imagine elevator and fire in front of my eyes , I hear a sound in my head saying do not use the elevator . You know , and I think that'll be a common theme . So perhaps let's try and go back a little bit , like where did the do not use the elevator came from and what was the rationale for literally banning them from existence in fire ?

Speaker 2 4:42

That's a good question and I can assure you that you are not alone in having those thoughts of not using the elevator in fire . Very common and basically everyone I talk to about my research , that's the first thing they say . Well , you shouldn't use it . And actually the recommendation or standard not to use it it was introduced in like the 70s or 80s . It's not really clear what it's based on . It's not really a stringent , it's not an event that you can trace it back to if we say it like that , but it's rather like a bunch of rumors in the 70s and 80s that there could be an issue with the elevator during a fire because the heat could activate the call button and then it could be transported to the floor of the fire and if the doors open , the smoke could activate the call button and then you could be transported to the floor of the fire and if the doors open , the smoke would block the photo sensors or the light sensors . That will close the door and you would be stuck there .

Speaker 2 5:34

And there are such events that have happened . There was one not too long ago , actually in Chicago , but once this recommendation was introduced , this was as far as I know . There's no recorded event of such a thing during that period and actually when the elevators were first introduced in buildings , like in the beginning or in the end of the 1800s or the beginning of the 1900s , they were manually driven by people . So you had this person that drove the elevator up and down , and there were several events . There were these elevator managers or elevator drivers actually saved a lot of people during fires . There's this Triangle Shirtwaist Factory , for example , which is one of the worst workplace accidents in the US Several hundred killed . The elevators were accounted for , saving a lot of lives .

Speaker 2 6:31

When did the fire happen ? It was in 1911 in the US . Okay , okay , yeah . And shortly after that there was discussions on one of the early standardization meetings in the US about actually having the elevator incorporated into the legislation as an escape route and to account it for a certain amount of stair width and stuff like that . But then it was disregarded again in 1935 because they were worried about the electrical driving . Then electrical elevators had been a bit more common . So I guess the switch between manual and electric elevators is kind of key here and people weren't really trusting the electrical elevators in the beginning . Uh , so then they stopped or started with the recommendation not to use it during a fire .

Speaker 1 7:18

There was also some uh fire in Germany , I think , some like 20 or 30 years ago , when people died in elevators . I'm not sure which airport that was .

Speaker 2 7:29

Yeah , I think there are some . I mean there's several fires where people have died . So , for example , the MGM Grand fire as well , people died in the elevator . It's not really accounted for being the cause of death in that sense , but it's . I mean , along with these recommendations , the recommendation were introduced to smoke-proof it because , as you know , a shaft through the building will accumulate smoke . Be at least a pathway for smoke , and that's not too good if there's people in there . So that's also one of the reasons , I guess , for not encouraging elevator evacuation in that sense .

Speaker 1 8:07

Your PhD is mostly on the behavioral aspects , but I would still like to touch a little bit on the mechanics of the person flow . So you said in 1911 , we'd already saved a lot of lives in one of the largest fires in the US . How efficient actually is like an elevator escape . Imagine we have a 100 meter tall building . Whatever , I guess it shines in the skyscraper . That's where I would assume it shines . How does an elevator compare to a staircase ?

Speaker 2 8:38

That's a very common thought as well and I guess one of the main drivers for introducing elevators would also be , as you say , like the efficiency and as the higher the building is , the better the elevator is compared to the staircase in , at least in like time to ground and most of the calculation studies there's a lot of calculation studies done on elevator evacuation and along with staircases and stuff , I mean all of the calculation studies I , I would say , come to the conclusion elevators are very . They increase the efficiency of evacuating a building , mainly due to comparing to stairs or other things that are not really as efficient . But one of the main pros with an elevator , I guess , is that it's actually designed for a certain load or personal load for serving the building . So for an office building you would have a design for peak time and you would have a certain design criteria for that elevator to accommodate a certain number of people , and when we look in Sweden , we would have phased evacuation .

Speaker 2 9:43

Most of the other calculation studies I've seen are on total building evacuation . In Sweden the most common thing is to have phased evacuation . Then a key question is would the elevator be able to compare to stairs ? Just on looking on a single floor for evacuation ?

Speaker 1 9:58

Yes , I'll interrupt . Sorry you segwayed me to the exact thing that I wanted to ask . I mean , you have to consider this in combination with the evacuation strategy . Uh , I don't think I've ever had a proper high rise episode of Fire Science Show . So in the high rise buildings you would most likely do evacuation of the floor where you have the fire and the floor floor above , floor beneath . That would be a typical strategy we would employ in poland . A total evacuation would be something that the firefighter that reaches the building announces , so it's a decision of the commander , not as that strategy you would employ normally , because you will get the staircase clogged with people and the higher you get if you start evacuating everyone altogether , the more clogged , the more blocked it will become .

Efficiency and Behavior of Elevator Evacuation

Speaker 1 10:49

So there's a very big shortcoming in evacuating through staircases . I mean , I'm not sure if everyone recognizes that staircases are actually not that easy to evacuate a tall building and it may take literally hours to get everyone out .

Speaker 2 11:04

If you want that , yeah , I mean I , I totally agree , and I think that's also a kind of a shortcoming in in most of the elevator studies that are made . They may basically all I've seen are on total building evacuation , which is not really a design scenario , or usually not . In some cases I guess it is , but but usually it isn't . And I mean the main question is can the elevators accommodate for evacuating a single floor , the fire floor , as you say like with the same speed and efficiency as staircases which would then be empty ? In that design scenario ?

Speaker 2 11:40

And I did a with together with two students , or rather the two students did the masterpieces with me as the supervisor , so I shouldn't take the credit it was Johanna Hammerberg and Håkan Niva who did it and they looked at just this elevator evacuation from a single floor , and I think it was published in PED , ped conference procedure a few years back .

Speaker 2 12:04

But then we looked at like so in that case for that office layout that we looked at , five elevators which was what was the design of the office as well accommodated for the same evacuation width as a 1.2 meter wide staircase , which would be the equivalent requirement in sweden as well , and that was regardless on what floor you look like if you looked at the fifth floor or the 50th floor . It doesn't really matter , because the the higher you go , the elevator can increase its efficiency due to higher peak it can keep its peak . What do you say velocity peak it can keep its peak . What do you say velocity in longer . So it's basically as efficient regardless of how high in the building it is , which is kind of interesting .

Speaker 2 12:52

I think 12 time is not such a great component in in in everything right exactly and it's much faster , as I mentioned , like if you're , if you have a really tall building , you would the people choosing the elevator will be out faster because they will reach the ground floor . But in this case the design criteria was just to leave the fire compartment so the other people would be compared to leaving out , going out to the staircase . And of course there is . There is some like you have to look at the size of the elevator lobby because it has to accommodate for awaiting people in in a different way than than the , but it's definitely , I would say , in a regular office building . You could probably have a very efficient evacuation with elevators if you compare the means of escape in that sense .

Speaker 1 13:38

In case of a fire evacuation , how would calling the elevator look like ? Is it locked to the floor of the fire ?

Speaker 2 13:48

I mean it would be annoying to stop at every floor going down , so I assume that's not the case yeah , I think that's that's also a good question and I guess that depends , like what's the purpose of the elevator ?

Speaker 2 13:57

We we just introduced uh , two years back the swedish standard on elevator evacuation and that mainly looks at evacuatinguating people who can't walk the stairs , and then the prioritization is not that important , I think , because you will still wait shorter time than you would in like an area of refuge , and cutting costs would be important because you don't want that solution to be much more expensive than the area of refuge , because then no one is going to choose it and it's introducing safety , even if you have to wait a few minutes . But if we're looking at the scenario as we talked about now , with an office building or you actually exchange an escape route with elevators , I would say you would probably have a prioritization scheme and probably , as you talked about earlier , maybe prioritizing the fire floor and then when you get no calls from the fire floor , you would go to the floor above and the floor below and then , when you have no calls from those , you would go for the rest of the floors .

Speaker 1 14:55

That's probably the usual way to do it . I also know that some common evacuation models I think Pathfinder has a elevator model you could play with . So I mean it's a commonly used tool in fire safety engineering elevator model you could play with . So , if I mean it's a commonly used tool in fire safety engineering , so if someone would like to try it out on their own on some case study , they have just build a model and then check it out , like run it versus a staircase . It's interesting . It's interesting to see how it works out . Anyway , let's move on to the main theme of your PhD , which were the behavioral aspects of elevator evacuation . So first tell me , like , why you are interested in behavioral aspects of this , like what behavioral aspects are there to consider ?

Speaker 2 15:38

I think you pinpointed it , like in the introduction here , like the first thing that people say are like oh okay , elevator evacuation , why are you looking at that ? No one is going to use the elevator anyway and I would never use the elevator in the fire and and that's the common answer you would get . And I guess that's also a relevant point like why , if we look at this office scenario , if , even if we introduce elevator evacuation , it's not going to work , if no one is going to choose it , so it's a main aspect of having it at all that people are actually using it , and I guess that's one of the main drivers .

High-Rise Building Evacuation Behavior

Speaker 2 16:15

I got into it by accident . I did my master thesis , I needed a job and there was a high-rise project at Lund University at that time with Daniel Nilsson as my supervisor , and it was pretty unspecified . But we started looking at elevator evacuation and that was , I mean , the reason for me , I guess , to get into it . But it's actually a very interesting subject because it's about what people have learned . It's about your perception of yourself .

Speaker 2 16:47

Like you think you're not going to use it , but when we look at like studies , the real studies or studies of field studies and also real fire events , people are actually using the elevator in almost all events we can look at . So there's a contradictory there . And there's also this aspect on how do we , how do we assess these ? Like if , if there is , if that's the case , that people are not willing to use the means of evacuation , how do we get them to use that means of evacuation ? So it's a multi like component question . And also we have that , the component of waiting time , like how long would you be willing to wait for elevator in a fire scenario ? And also , can we increase that time if we do something about it , if we introduce a technical system or information system or something like ?

Speaker 1 17:37

that . So it is also kind of a choice like , because you will most likely have a alternative path , being this the staircase you know present to you . So the question is uh , at what point you'll stop , you know , give up and go with the stairs , right is that ? Is that a part of the , of the willingness ?

Speaker 2 17:56

exactly so . So I mean the . The one part is would you ? What is your primary exit choice like ? Is your primary exit choice the stairs or the elevator ? And how does that change with different aspects ? So the first studies looked at the height of the building and you would find that you have probably an increased probability of wanting to use the elevator the higher up in the building you are , which may be natural , but it's not as natural when you look at it in the following studies . But it's a natural thought , maybe , maybe , and it's also so .

Speaker 2 18:32

You have the primary exit choice and the factors that affect that , and then you have like , once you choose the elevator if you choose the elevator , we have the waiting time . How long will you be able to wait and what is your alternative ? As you say , would you , would you go to the staircase ? In that case , how long would it take and what would that mean ? Would you pass ? Would you be , and what would that mean ? Would you pass ? Would you be , so to say , impatient that you would actually go back through smoke , or would you stay and wait for that ? And I mean some of these questions we still don't have answers to , but there's a lot of interesting behavioral aspects to look at .

Speaker 1 19:04

It's also interesting from the architectural point of view because the modern office buildings and the high rise development you'd have , you'd have a very central elevated lobby where the normal traffic would occur for the building and at least in the buildings that we design in Poland , the staircases would be , you know , just attached somewhere remotely , not necessarily directly , to that lobby , probably connecting to some corridors under the floor which they serve . So , technically , people who would be going through everyday use of the building , they may not even ever go to the staircase , may not even see the staircase . You know , it's not the choice that , oh yeah , I have . On my left hand I have elevator doors . On my right hand I have doors to the staircase . It can be in a different part of the building , you know , and this makes the decision a little bit more difficult , and it probably just when you start making the decision whether I evacuate , you have to pick your pathway .

Speaker 2 20:09

Yeah , I mean , I think you're spot on here . And it's also a very interesting part about the elevator evacuation things , because one of the central behavioral theories we have in human behavior and virus is the affiliation theory , which is pretty much that you would probably choose the way that you're acquainted with or that you usually take if you're in a stressful situation , and in most high-rise buildings that would be the elevator . But if you're not going to use the elevator , then what are you going to choose ? And I think it's also where we looked at . As I mentioned , there's a lot of like one of the central aspects here like it's that people are saying that they they are not willing to use the elevator and that's based on a number of questionnaire studies that are done . So when we do questionnaire studies and make people imagine a fire scenario , they would say that they're not especially willing to use the elevator . I think in average there's maybe 10% to 50% , depending on building floor . When you have really high buildings , more people would be saying that , okay , maybe I'll choose the elevator , but in general there's around 10% maybe willing to use the elevator as an escape route . But when we look at real fire events where you're not supposed to use the elevator .

Speaker 2 21:25

We have higher elevator usage than that in many cases and there's also when we did a field study , like an unannounced evacuation study , we saw that there was almost exclusive elevator usage . It was 95% of the people in a hotel building on the 16th floor that used the elevator for evacuation and that was very surprising to us . It made us rethink the whole , the whole experimental layout . But one of the reasons for that and now this is a very long answer to your to your question but but one of the reasons for for them to choose the elevators when we interviewed them afterwards was that they did not even know that there was a staircase in the building . They , they I mean as a fire safety professional .

Speaker 2 22:08

We would say that everyone knows that it's two ways out . You always have like two options , which is not true for all buildings , but for many buildings it's true , and you would definitely say that the most common way to evacuate in a high-rise building is a staircase . But for these people , 75% answered that they were unsure if there was another way out than the elevator from that hotel building and I think that's a misconception that we , as professionals , we think that there's a general level of knowledge on escape routes that may not be there for people in the real world , which also makes elevator evacuation like . I think it's kind of an important question , because if people are going to use them anyway , there is a reason to design them safely and actually accommodate for the efficiency that they can provide . And if we're not going to be able to use them , we need to make sure that people are not . I mean , if they're unsafe to use , we need to be very strict about how do we get people not to use them .

Speaker 1 23:09

Have you seen the similar patterns in different buildings in high-rise ? I don't know what you've studied . Perhaps I've mentioned a railway station , perhaps settings like that . Have you done something like this ? Or maybe sports arenas ?

Speaker 2 23:25

Erik Bjontegard Now I get excited . No , we looked at . So the only field study that is out there , I think , is a study we did on a hotel building , the hotel building I mentioned . So that was a high-rise building .

Metro Station Evacuation Strategy Interview

Speaker 2 23:37

But we've also done questionnaire studies and a VR experiment for a underground metro station , which is based on a real situation in Sweden , where they're building a metro station which is approximately 100 meters below ground in Stockholm and basically to achieve the efficient evacuation , we need to use the elevators , because it's too far to walk 100 meters upward .

Speaker 1 24:08

Why are they building metro stations a hundred meters below there ? For fun ?

Speaker 2 24:12

No , it's not for fun . I think they would have chosen not to if it was possible . But it's because they're going on below sea level in central Stockholm to get down to the traveling tunnel . They don't want to build it through the sea , so they want to go under it , the NATO lake now , yeah , exactly .

Speaker 2 24:35

And in that case we looked at first there was a questionnaire study looking at would you be willing to use the elevator for evacuation from a metro station ? And then with VR , to see what is the base case . And that is , people are probably going to use the stairs in a metro station because elevators are not that common in in metro stations , not for normal transport , so people won't be expecting to use them in the same way as in a high-rise building . But then we tried , like a different , a bunch of different technical systems and so that we we can actually increase the elevator usage to the amounts that we need to make the design criteria in that case , in case of your metro station .

Speaker 1 25:18

okay , that's kind of different choice , because you probably have staircases . I assume you must have staircases , but you probably also have escalators and these movable automated stairs that move up . Are you utilizing those for evacuation as well ?

Speaker 2 25:35

Jan-Pieter Pozner . Actually , this station will not have escalators . You will . So for normal use in this station it's too far to go down with escalators . It would take a long time to from surface to a hundred meters . Gideon Lenski . Vertical transport . Jan-pieterical transport . Yeah , so for normal use you would use dilators in that case , which is very , as you say , like that's not really a normal situation for a metro station . So it will be .

Speaker 2 26:02

I guess for people who are used to that station it will be a different behavioral aspect than for people who are just visiting it and stuff like that . So there's a lot of things to think about . But we treated everyone in that case as visitors , people not knowing the station , pretty much . So you would go down to like a platform or a top level and then you would use escalators to get down even further to the platform level . So in the evacuation case you would have escalators to take you up to the elevator lobby . But then you would have the choice to either use one of the really large and I think it's like eight or 10 elevators , very large ones or choose one out of three staircases , I think , or two or three staircases , but , as I said , we don't want too many people to use the staircase , because it's actually going to be like a very high physical stress for you and it's probably going to get clogged pretty quickly because upwards rather than downwards and yeah , it's a lot of problems evacuating that sort of height upwards .

Speaker 1 27:07

Well , actually walking down many flights of the stairs is quite challenging as well . You would perhaps not expect that , but if you walk like 25 flights of stairs and we sometimes do it when we commission a high-rise building and the elevator guy goes home because we stayed too late You're only too busy then to go to sleep on the concrete or walk down .

Speaker 1 27:30

Apparently , it takes a lot of time to walk down . Okay , so so elevators seem to be seem to make sense in the evacuation . You can accelerate the process . You can evacuate people from the floor of origin More conveniently obvious benefit which we didn't even mention , but it's kind of obvious . For the disabled people . This is significant improvement . However , when I was talking to Marie Watson about building fit for disabled people , she mentioned that the lobbies need to be designed accordingly to accommodate a disabled person with a wheelchair . Also , it's kind of a stressful situation to wait Like was this something that you have investigated ? I mean , you've brought up the willingness to wait , so perhaps tell me , like , how willing are people to wait for an elevator and how long they can take , and are there any strategies to increase the time ?

Speaker 2 28:23

Yeah , I think that's a really interesting question also , and it's so for people who can't walk the stairs . It's it's also a different situation , which not a choice , really right . Yeah , I mean there is a choice . There is because there is like this real event that has been accounted for in different journals or interviews and stuff like that , that people have actually left their wheelchair and started like trying to get down without the wheelchair , bumping down on on the stairs and stuff like that , which is , of course , that increases the the difficulty of for the rescue service once they arrive . That .

Speaker 1 29:00

I mean it's a very complex then to it must be pretty traumatic to a person's will definitely and it's .

Speaker 2 29:07

I mean , if you're so stressed that you actually leave the stair , your movement device , it probably looks horrible , I guess . So there's probably a discrepancy in the waiting time acceptance for people who don't have that choice and people who just they can actually just choose to take the stairs in that case . And there's some studies on areas of refuge and willingness to wait as well , and they actually don't show that long , but they're a bit longer than people answer that they would stay in elevator cases . And when we look at elevator , I mean it's a difficult factor to actually study , but we tried to study it , for example , in virtual reality .

Speaker 2 29:53

So for this metro station , as I mentioned , we studied waiting time and we studied different techniques to get it , to prolong it , or at least one technique . We introduced a timer over the elevators and so the accepted waiting time if we didn't have a timer . I don't remember exactly , but I think it was around like one to two minutes or something like that . There are some people who actually leave quite early and they are going to leave quite early even when we introduce the timer . So I think it's around 10 to 20% or something like that .

Speaker 1 30:24

What does timer show ? The time to arrival or how ?

Speaker 2 30:27

Yeah , so we just simulated . So we put the timer over each elevator as I mentioned . It was , I think , eight , six or eight elevators or 10 or whatever it was , and we put just between three to five minutes . So once you push the elevator button they started to count down individually from different times , but between three to five minutes , and then the elevator didn't come when the timer reached zero . So we wanted to see what people did then . Uh , just to mess them up , you're awful , but yeah , but it was in virtual reality reality , so it wasn't that stressful it's it and there was no fire in it and stuff like that , and that would be .

Speaker 2 31:04

The people would actually wait longer or more . People would wait until at least the first timer reached zero , but there's still like a decent amount of people that are not willing to wait more than more than a minute even if you have a timer and then there's some people who actually wait I mean around , I think it was 10% , something like that wait past all the time , is reaching zero and keeps waiting a bit after that and then leaves .

Speaker 2 31:32

So there's a big discrepancy , but the the general acceptance is quite low . I would guess it's not much more than a minute at least if you don't get any like good feedback on what the elevator is doing . If you get feedback on what the elevator is doing , you're gonna probably increase the accepted waiting time and you probably can increase it a few minutes . But if it's more than than a few minutes , yeah , you , you're going to have , like , the people who are not dependent on using the elevator will probably leave and try to use the stairs instead , and the people who has to wait will probably wait longer . And there's also , like the studies that looked at this are also one of the factors that people who's in wheelchairs or can't use stairs for other reasons they want to have like feedback . Of course , everyone wants feedback . So what is the elevator doing ? Why is it taking so long ? If we can provide that information , then people are probably willing to wait , maybe for as long as it takes , or maybe at least a few minutes , which would probably be .

Speaker 1 32:37

Does congestion playertsson Does congestion play a role in that , in terms of how many people are waiting for the elevators ? Like either positively , like you're enforced that others are waiting too , but you can also be discouraged . Oh my God , there's like a hundred people waiting for elevator and you know it can take six of them .

Speaker 2 32:53

Jan Bogaertsson , I think you're again . This is a very interesting I mean behavioral aspects . As you mentioned , there's both the fact that you don't want to wait , if you expect the waiting time to be too long and there's a lot of people in the elevator lobby , you would be discouraged from waiting . But at the same time , again , one of the key theories is social influence in evacuation , so you're probably going to follow other people . Theories is social influence in evacuation , so you're probably going to follow other people , and that's those . These two factors contradict each other in elevator evacuation , in the same way that the exit choice contradicts what you naturally would do , and and the evacuation behavior which makes it very interesting .

Speaker 2 33:31

It's it's really hard to study . I mean there's there's a questionnaire study by mckinsey and galea and the p Lawrence in the UK where they took pictures from the simulation program with different densities in the elevator lobby and looked at how people's exit choice or in the questionnaire . What would people answer depending on the density questionnaire , what would people answer if , depending on the density ? And then they saw like if there's a high densities , people would be discouraged from using the elevator , at least in the questionnaire . But as we , as I said , the questionnaires aren't really that reliable , which makes it very interesting to see , like , how would that perform actually in reality ? And there's no real good studies on that . There are some , some studies from china that looks at elevator loading and unloading and they have a congestion factor where some people who aren't once you have like a full elevator and it travels down , some people are going to leave and take the stairs instead of waiting . But unfortunately , like the setup and the experiment setup was informed so they knew they were taking part in an evacuation experiment which would probably affect their behavior and also there wasn't that much people .

Speaker 2 34:46

So it's very hard to make any conclusions out of those results . But I mean , that's a very interesting question . There's some indicative studies that says that you're probably going to be more prone to using the stairs or changing from your first evacuation choice if there's a lot of people waiting in the lobby . But we can't really be certain . There's a need forperson account that says that on some floors there was a really long like there was . I think the first-person account says that there's a block-long queue to the elevator but people were still like I should probably take this there , no , let's go for the elevator , and they would stay and wait for the elevator , even though there was a lot of people there . So I mean , it's a very interesting behavioral aspect .

Speaker 1 35:39

One massive difference between staircase and elevator is that if you're talking about evacuating a single floor at the beginning of your phased evacuation , your stair capacity is pretty much unlimited because it's designed to accommodate those Like you probably will have a queue which is a result of the flow rates through the doors , but you could assume that everyone will eventually enter the staircase and they are in area of some sort of safety . In case of elevator lobby , the lobbyist that I know would not be that big . I mean , it's every square meter that you're spending for lobbies , not a square meter sold to a customer who's buying the floor . So it's a lost money . So everyone would minimize those lobbies as much as possible . And what even makes it more ?

Speaker 1 36:30

There's an interesting dynamic because if you have a really tall buildings , like 200 , 300 meters tall , perhaps even at 100 meters , you would already see that Some elevators would reach like floor 20 . Some elevators would like reach level 40 . Some would go to level 50 . Not all of them go all the way up to the building . Because you reduce the number of elevators , you increase the number of square meters at upper floors which you sell at higher premium , right ? So the lobbies get smaller and smaller and smaller the higher you get into the building in spaces where you need them more and more and more . It's a really challenging dynamic .

Speaker 2 37:08

Yeah , I mean you're perfectly right , but I guess that's in essence it's like what the science and area are looking at . Is it the full building evacuation or is it the the single floor evacuation ? Because in the single floor evacuation you would probably also have a much higher elevator efficiency because , well , once the fire alarm goes , you , you would probably have the elevator , go to that floor and wait for people . So the first like round of people who comes would probably already have the elevators there and then you would . So that's like when we looked at this elevator , like on a single floor study , actual lobby size that we had in the building , which the elevator consultant had derived , was actually enough , sufficient to have the same queuing time out of the fire compartment as towards the stairs , depending on what split we looked at . But I mean , that's depending on what is the scenario . And if you have a full building evacuation , maybe the lobby size it's not that important that everyone reaches the lobby that quickly because you can actually queue out in the floor without having fire reaching you .

Speaker 1 38:13

This is such an interesting dynamic . You know , if you think about staircase , the staircase would be sized for a single floor and everyone would be using it . And an elevator is reversed because it's designed for the entire building and you use all that power for one floor . So it's actually reversed efficiency . It's more efficient in fire than it would be in a general case . It's very interesting . How about ?

Elevator Safety Guidelines and Standards

Speaker 1 38:37

You said you were working on guidelines for Sweden for use of elevators ? Did you put any specific requirements towards the lobbies ? I don't know . Compartmentation , smoke control sprinklers .

Speaker 2 38:51

That's also . I mean that's a very important aspect because when we look at elevator evacuation , I guess one of the key questions for a designer would be like what is , as you say , what is the protection requirement ? What do we compare the elevator with if it would be a stair ? Pretty much so in the Swedish standard for elevator evacuation , which is kind of new and it's kind of a short standard with a lot of annexes instead , which makes it maybe easy or hard to use depending on scenario , but it's basically designed in Maine is the design of elevator evacuation for people who can't walk the stairs .

Speaker 2 39:34

So the Maine comparison made in like the basic part of the standard is that in sweden you would have a requirement for an area of refuge . But if you change that to an elevator , how would that look like ? And actually an area of refuge is a very unsafe environment . I mean it's basically a separate fire compartment where people can wait until they get help from the rescue service or the stairs or whoever it is building management and it has a fire compartmentation requirement , but there's nothing else . It's and a communication device . In sweden it would be um , and then you , you get to sit there and just wait until someone helps you and you would have a fire right outside .

Speaker 1 40:17

Yeah , that's a very stressful situation probably .

Speaker 2 40:20

And if you just exchange that , I mean if you put the elevator and the elevator lobby so , a normal situation in Sweden would be that you would have this area of refuge in the elevator lobby actually , and if you just say , okay , hey , you can use the elevators until there's smoke or heat in the lobby , the elevators until there's smoke or heat in the in the lobby , that's actually it's very easy to say that that's probably a safer solution than just sitting and waiting in that area .

Speaker 2 40:45

So the standard does not introduce too many requirements on the elevator , but it also says , like , if you're going to do something , if you're going to as we have talked a lot about here if you're going to change one of the escape routes for for elevators , then you're gonna have to equivalent the safety that would be required for a stair on the elevator and the elevator lobby . So so the key like concept is that you look at the elevator and the elevator lobby as the flights of the stair and that would be the requirement . So so in sweden , for example , again , you would have the higher the building , the higher the requirement on the protection of the stair . So for a certain building you would have a protected lobby outside two doors until you leave an occupancy , and in some cases you would have either . That lobby should be open to the outside .

Speaker 2 41:32

But the usual design concept is that you pressurize the staircase . Like design concept is that you pressurize the staircase . So if you're going to change that sort of staircase to elevators , then you would have the same requirement for the lobby . So you would have a separate fire compartment or fire lobby in front of the lobby where people are actually waiting for the elevators .

Speaker 1 41:54

Yeah , like a separate compartment that you go through to enter the elevator lobby , and would you pressurize the elevator lobby itself or the elevators themselves ?

Speaker 2 42:04

Yeah , I mean , if you're equivalenting it to a pressurized chair then you would also pressurize that way of having it . But I mean the key concept here is looking at how fire protected are people that are actually standing in the staircase and making their way out , and that is the equivalent safety that we want for the people who are actually , who are just waiting for the elevator because they are in in the evacuation cells . They are in the same place , they are in their travel .

Speaker 1 42:31

So in Poland I think we're overdoing it kind of because we would have normally two staircases , both pressurized . You would have lobbies connecting those staircases to corridors . The lobbies would themselves be pressurized . The corridor would be with a smoke control actually taking the air from the lobby as an inlet and extraction at the corridor . So the flow path is established from the staircase to the corridor in all cases , whether the doors are open or closed , and you would have the elevators pressurized , not for the life safety but to limit the spread of the smoke through the building to elevators .

Speaker 1 43:09

And the elevator lobby would not really be any way fire compartmentalized . It would be closed usually because you want to block the noise and for you know , crowd control , say security and stuff , but it would be usually pressurized because we're talking about the middle of the core of the building . You would usually also have your air inlets in that space to transfer air to the corridors and we would not use the elevators for evacuation usually . Typically , even though we have such a nice combination of safety systems in there , I think those elevators would be actually quite safe to use in escape . How ?

Speaker 1 43:52

about firefighting elevators Sorry .

Speaker 2 43:55

Oh , finish your thought on that last one .

Speaker 2 43:56

No , yeah , sorry I'm interrupting you , but I think that I mean that's a very , that's much stricter requirements , I would say , than there is in Sweden .

Speaker 2 44:05

We would not have that sort of design . But I think the general like concept that you touch on here is relevant for a lot of legislations and regulations and standards around the world that the elevators are actually pretty safely designed but they're not used Because we don't want them to be a pathway for smoke or stuff like that . And I think in many cases , like when we look at buildings , it's not that costly or it's not that difficult to make the elevators actually safe for evacuation and to go into firefighter evacuation . As you mentioned , here in Sweden we would also have a requirement for firefighter elevators above the 11th floor . So we have those in a lot of buildings and if we can design elevators to be safe for firefighters who are actually going into a fully developed fire pretty high up in the building , it's reasonable to assume that we can design elevators to be safe during the evacuation period of that same fire , because that's probably going to be a much easier fire to protect the elevators against .

Elevator Evacuation Safety Strategies

Speaker 1 45:20

The firefighter elevator would be a little different device because it operates differently . It requires a key to operate , there's no call button . The doors open and they close automatically . There are some additional levels of layers of safety so that firefighters do not enter the floor of fire and then get stuck in there . So that's an important feature . But indeed we and usually you know , in many cases that would be the same elevator that is used for everyday use . It just has a second door in the back which the firefighter uses to enter a secret lobby that's on the other side of the shaft . That's how often they would be built in Poland .

Speaker 2 45:57

so it's I would say in Sweden we usually have the same lobby , so so it's uh , the firefighter elevator often use and use the same lobby as as the regular elevator and the other elevators and that's that same . So you basically have the this . I guess we we base our design on the same European standard , but there's probably a discrepancy in how we use it in practice and I think in the general in Sweden you would have a protected space outside which is the same . As you say , there's also additional layers of safety . You protect it against water , you protect it against power failure and stuff like that . You protect it against water , you protect it against power failure and stuff like that and some of those features .

Speaker 2 46:40

If you're going to introduce elevator evacuation , that may be relevant , depending on what . Again , what are you actually equivalating ? Are you equivalating an area of refuge ? As I said , that's very easy to say that just use the elevator , probably safe or safer at least than the compared solution . But if you're comparing it to a pressurized stair or something that's going to be there for evacuation and for firefighting for a long time , you would probably have to introduce a number of layers of safety which probably would be kind of similar to the firefighter elevator in many senses , but different in other senses .

Speaker 2 47:18

I mean's there is a european proposed standard for for evacuation lifts , but it's focused with focus , yeah , and it's . It's take a base on the firefighting lifts , I think , I would say , and it has like different features . So it has like manual drive , that someone has to come there and drive it , and then it has like some sort of there's a supervision Someone looks at like sits in a control room and steers it , and then there's an automatic option and I think that all other like options than the automatic one is probably not . It's very hard to get that to work , but if you have an elevator and you actually can protect it properly and it can just do its job , it's probably going to increase the safety for that building . I would say .

Speaker 1 48:07

Okay , I'm now going to ask for your opinion and I emphasize that it will be an opinion and it's a dadgerous question , so watch out how you answer it . But do you think , given all your experience with emergency elevators , that you could have a building designed for , I don't know , 30 floors or something high-rise building ? Take one staircase out of the building , replace it with evacuation elevators and provide the same degree of safety in that building ?

Speaker 2 48:40

Yes , I definitely think so . Yeah , I think so , and there is one such building . I mean , as I mentioned , we did this hotel study and that was actually in a hotel in Sweden which is 35 floors in a 35-floor building where they have switched one of the staircases . So in Sweden we have a general hotel requirement with these two staircases here , one of the staircases there's one staircase and there's one like elevator , five elevators for evacuation . So we did the study in that building because it's very conveniently designed for such a study .

Speaker 2 49:14

And , as I mentioned , I mean , the basic indication from that study is that most people are first at least going to go heading for the elevators , because that's the way they came in .

Speaker 2 49:25

And if the staircase is not there which , as you say , in Poland and in many Swedish buildings you may have like an elevator , separate elevator core and then a stair in some other part of the building that would probably have people going to the elevator core and then having to find their way's out there .

Speaker 2 49:42

It's highly probable , I would say , that some people are going to try to use the elevator during an evacuation , even though that might not be a part of the evacuation strategy , that it's probably not a part of most buildings' evacuation strategy , but I think that in most cases people are going to try to use the elevators and if we don't accommodate for that behavior , probably less safe design than actually accommodating for the real behavior that we're expecting . So my personal opinion would be that you can definitely design a building with an equivalent level of safety using elevators instead or together with a staircase . And I also think , and a prolong of that opinion , is that we should probably design more buildings for elevator evacuation , because that is the expected behavior in quite a lot of buildings , actually All buildings where we have that as an entry and you know what .

Speaker 1 50:55

Go ahead and try to feed the staircase to an already existing high-rise building . Good luck with that , while every high-rise building since 1850s would have elevators for vertical people transferred , and actually that is something you can work with and adapt on . So in most of the existing buildings , it's not that you have every choice , really no . So exactly .

Speaker 2 51:20

I mean , we we've talked about people who can't walk stairs , which is an obvious situation , and it's , I mean , that's a component which is more relevant , I guess , in all countries now to to design for , which hasn't been designed for that fully previously , which is very I mean that's a very important argument for elevator evacuation , I would say , and there's also , like hospitals and other occupancies where what is the actual options ? So I think it's really are the options actually an option or is it just something that you could put on a paper ? The option's actually an option or is it just something that you could put on a paper ?

Speaker 1 51:56

I'm pretty sure that I've heard about building designs where they've proposed emergency parachutes before they proposed to use elevators . Actually , that's how big the stigma is , and I'm pretty sure that an elevator would be safer than a parachute Anyway . So let's end up on this . I'm sure you'll be flooded with poems from UK now after this , and I hope that . Thank you very much for coming to Fireside Show , for explaining the evacuation elevator concept to us , and good luck , man . Thanks , it was good talking to you and that's it . Thank you for listening .

Speaker 1 52:32

I wonder , after all of this , what's your stance on evacuating a building with elevators For me , I'm almost quite shocked with the stuff that Axel said Well , particularly because it made sense . It made a lot of sense , and I was kind of ashamed that I did not view the world of evacuation like this before . It's kind of ridiculous that we do all those things because you shall not use elevators . You shall not do this . There is this golden number and we stop looking for sources , stop looking for ideas , stop looking for explanations , and perhaps we should do more . Well , the podcast , the Fire Science Show , is one of the ways where I'm trying to find such food for thought for you and for myself and educate myself . And yeah , today I've learned that you can build a pretty good evacuation strategy using elevators on par with at least rescue areas and perhaps even on par with a staircase . This is amazing and I will be working on that and thinking about it more in the future , professionally .

Speaker 1 53:37

And in Poland we already have one building , as far as I know , maybe we have more , but one that I know of that was designed from scratch with one evacuation staircase . I'm not sure what kind of elevator evacuation strategy is employed there , if it is there or not , but I can see , I can imagine that there will be push for more buildings like that . Our law is very strict , so it's not something you can just do , and here we gained a new tool to play with , and I'm pretty sure my friends and colleagues from UK will enjoy this episode , because I hope that for your struggles , this is also a very , very interesting insight . So thank you very much , ax Axel , for coming to the fire science show and sharing all of that and looking forward for your future research , and perhaps I would like to visit that 100 meter deep underground metro station in Stockholm one day to see it for myself . That's it for episode 151 of the fire Science Show . Thanks for listening and looking forward to have you here . The same time , same place , next Wednesday . See you .