CTBUH 2012 Shanghai Congress - O'Connor, "Considerations for Refuge Areas in Tall Buildings"

Good morning, or is it just about afternoon? We're up against the lunch hour, so I will try to get going here promptly. What we're going to talk about today has to do with refuge areas in tall buildings. This week, particularly the last two days, we heard a lot from the developers, and from the finance and investors for buildings. Today, as I go through my presentation and talk about refuges, think about the impact of refuge areas, particularly refuge floors, on the financial model for these buildings and the sustainability aspects of these buildings. What I want to talk about today is really not so much my opinion, but it's really a collective dialogue we've been having within the CTBUH Fire Safety Working Group. To give you a little background, the Fire Safety Working Group has many very experienced engineers who have worked on many tall buildings around the world in Asia, Europe, and the Middle East. One individual was particularly interested in us having a little more critical thinking about how we use refuge floors and refuge areas in buildings. He brought this to our working group's attention, and we started to have a dialogue about this. The dialogue has continued for about the last year and a half, and we've been preparing this paper. This presentation today was presented at the CTBUH conference in Korea, but this is a little bit of an update with a couple additional things we're going to talk about. The important thing is that we thought we needed to maybe slow down and think a little bit deeper about how refuge floors are used, what is their value, and what are they trying to do. I'm here today to bring forth a lot of what our dialogue has been about, and maybe a better understanding for you all about the issues, concerns, and reasons to consider or not consider the implementation of refuge areas, particularly refuge floors, in buildings.

What's been some of the basic reasoning? If you look at the literature, and we have looked at a lot of the literature that's available on reasons people have used refuge spaces in buildings, one is of course taller means longer evacuation. We know that for super tall buildings, evacuation can be on the order of 1 to 3 hours. Certainly, with a super tall building, to descend the stairs can be a physically demanding exercise for people. We recognize as a matter of common sense that stairs are not conducive for people with mobility impairments or health impairments, or those having temporary medical conditions like pregnancy or a broken leg. Also, with super tall buildings, for a lot of standard emergency events, perhaps total evacuation is not a desirable or feasible thing to do. If you have a building with 10, 15, 20,000 people in a super tall, is it really something you want to have a full evacuation of that number of folks? It's been done, but is it something you want to do on a regular basis? So that's a reason people have suggested for having refuge spaces. Let's talk about stairways. People suggest, and we know by looking at the literature, that smoke contamination can certainly be a problem if pressurized and multiple doors are open. If we have a large evacuation, or for some reason many doors are open on a stairway, it's going to be difficult to maintain those evacuation routes in a smoke-free condition. Hence, maybe you want to put folks into a refuge area. Of course, there can be a reason for moving folks into a refuge floor to avoid conflicts with fire brigade operations. This is some of the background we see in the literature, reasons that people have decided to implement refuge areas and refuge floors in buildings. But when we started to look at this and break it down, we saw that there were really two basic methodologies of providing refuge areas in buildings, and I'm going to talk about both of those today.

One approach is what we call the dispersed approach. The dispersed approach is an approach that's been used in North American cities, Canada. It's really used in North America, with some implementation in Europe and the Middle East too. The options available in the dispersed approach are that if I have a fully sprinklered building, each and every floor in that building can be considered a refuge area. That is a fundamental tenet of the requirements for sprinklered buildings in the US and Canada. There might be other ways to do this though, to create dedicated areas of refuge on each floor in a building. For those of you staying in the Jin Mao Tower, if you're up on the hotel floors, which is a beautiful atrium space, the way the refuge is really done there, I speaking with some people this week, I found out that the refuge areas are actually using this dispersed approach because they use a protected elevator lobby on each of the hotel floors, rather than having a large refuge floor somewhere in the building. However, this building does have refuge floors too in the office areas. Horizontal exits, I'll explain a bit more about this concept if you're not familiar with it, and then of course ramps to grade. From a super tall, we're not going to build ramps down to grade from a super tall building, so that's an option available for low rise. Here's kind of a fundamental look at what the dispersed approach is about. Just trying to graphically represent that if we have sprinkler protection to deal with the fire at the point where the fire occurs and deal with it immediately, put the fire out, then we need not be so concerned about moving people around the building to another refuge floor location. From this aspect, we can say that all the floors in the building can act as a refuge floor. We can go a little bit further and say, for dealing with those with handicapped issues, we certainly have the potential to put wheelchair spaces in the stairways too, so that folks who might be heading towards an exit can find refuge in the stairway too, even though it is a sprinklered building. This would be something you might see. I'm from Chicago, and in the buildings in Chicago that are sprinklered, every stairway is required to have at least one wheelchair space in the stairway. That's the dispersed approach.

Another way of providing for refuge in buildings is the concept of horizontal exits. This basically says that if we provide a fire separation in the building, a rated fire separation probably would be a two-hour separation that extends from exterior wall to exterior wall, people can leave from the fire side to the non-fire side and be in an area of refuge. That's a concept quite often used in healthcare and hospital type facilities. But also, as Anthony Wood pointed out in his opening comments today, bridges such as those at the Petronas Towers can definitely serve as a valuable method of exiting the building, coming down, crossing over into another building, and as he said, to a building that's not at risk. Bridges can be a valuable way to achieve horizontal exits too, either inside a building or moving from structure to structure on these bridges.

Continuing our discussion about the two methods of providing refuge, the second approach is the consolidated approach. The consolidated approach is really what we find here in Asia being used regularly. The consolidated approach, from what we can find looking at the literature, seems to have been an outcome of several Asian fires in the 1990s, including Hong Kong's Garley Building. If you really go back and look at that building fire and the reports on that fire, that building didn't even really qualify as a high-rise structure or a tall building; it was only about seven stories. The fire started in the basement, but it was a bad fire. Out of that discussion came the need and desire to create refuge floors in buildings. In using this consolidated approach, we say let's move people to one central floor area or to one of several floors located in the building. We do that for a couple of reasons. The literature seems to indicate that these are good places to pause during the evacuation process, perhaps you're tiring from moving vertically through the building. It also is assumed that these are safe holding areas and that you can stay maybe in this refuge area for a long period of time and wait for further instructions to further evacuate. What we see in the requirements in Asia is that these refuge areas are required maybe every 15, 20, 25 floors, it varies. I'll talk more about that in a few slides. In India, the requirement for refuge space is one every seven floors. Also, one thing we see in the application of refuge floors in buildings is that a common feature is interruption of the stairway at the refuge floor. That is a very common architectural feature that is used now. In this building, the Jin Mao building, if you're in the office parts of the building, in the upper levels we have application of the dispersed approach, but in the office portion of the building they actually use the consolidated approach because they have two or three levels that are refuge floors in the building. As you come down the stair, you can leave the stair and go into a corridor that then connects into a room that's on the order of, I was on the 15th floor, they had two of these rooms, they were on the order of a thousand square meters in area, just big white empty spaces. You can look out the windows. I don't know if on the tour they showed you those or not, but they do have those in this building. So this building in effect uses a mixture of both approaches, I found that interesting this week.

Let's stop and slow down, take a look what the refuge floor concept is about. In the refuge floor concept, basically what we're saying is we're going to dedicate one floor out of our tall building to refuge for occupants. That allows for us to have this dedicated area, and we might say let's move people down to this refuge floor. Effectively, we take an area that's empty and move a large population of people into this floor, either to wait further instructions or maybe because they decided they could go no further in the building because of the type of event that happened. There are a number of issues when we do this. Moving all these people to a floor, there are a number of serious design issues that include: are toilets needed? Do we need drinking water on these floors? It depends on how long these people are going to be there on these refuge floors, what the nature of the event in the building is. Do we need to provide seating facilities, or is it just going to be standing room? Certainly an important consideration can be what is the emergency power for the lighting and the floor amenities that are provided in this refuge floor area. Also, there can be issues related to how well is this floor area protected against increasing fire spread in the building, whether that means flames or smoke. Then, once we move everybody from all these floors who were probably on floors that had an HVAC load as needed for the population, now we have all this large potential population on the refuge floor, what does that HVAC design need to be to accommodate them?

Then there might be some safety issues that we see related to application of refuge floors. Looking back at the literature by a number of Asian authors, we see a list here of Quach, Chang, and Chow, and Chow. You can find these references in our paper. They have all pointed to the fact that when refuge areas are done, and I think Hong Kong likes to use the concept of having two opposite walls open air, they pointed to the issues of potential for smoke contamination of those open air areas from fire and smoke that might be venting out the building. Also, there are HVAC system function considerations. Is there going to be adequate fresh air for the population there, and are we going to pressurize this area to try to keep contaminating smoke out? One of the things I have a particular interest in is human behavior in fires. One of the things I become a little bit concerned about is overcrowding, the potential overcrowding issue. If we have this large crowd of people here, remember the building may have been designed with only two or three stairs to serve the upper floors. Now we've created a much larger population that's a factor of four, five, six times normal to this floor plate area, and we still have maybe only the same number of stairs. So we've essentially maybe created an assembly occupancy in an area, but yet we might have still the same number of stairs. Should a fire event continue and get to the point that this population needs to move, then we may see some problems with overcrowding as people push to the stairways to continue their evacuation of the building. I've already mentioned the issue of protection of the floor from increasing fire spread from floors below perhaps, and we've talked about the large assembly of people.

Another big thing we see, and again this goes back to the financial models for tall buildings, is what are the costs associated with these refuge floors? There are a number of different things that can impact the financial model for the building: additional construction time to add these additional floors into the building; cleaning and HVAC costs for normally an empty space; and definitely a loss of efficiency and an impact on the potential leasing plan and leasing model for the building. There might be definite issues with the usability of the building when you have to interrupt a tenant who wants perhaps four, five, six floors in the building, and then you have to tell them that we have to interrupt your operation with the refuge floor out of the number of floors you would like to take. Certainly there might be property tax issues. Are these floors and zoning potential issues related to this, because are we losing zoning potential by having to add these additional floors in, and what are the property tax issues related to having an empty floor that sits there dedicated for the use of refuge? These are questions that go to the financial model of tall buildings and also go to the sustainability aspects of the tall buildings. Depending on the similar building here, you can see that if you're providing every 20 stories, you're taking up a floor here and a floor here. But if you go to every 15 meters as India requires, then you would maybe have refuge areas in this fashion. But in either case, you might be taking quite a bit of real estate up and the loss of revenue.

One of the things I wanted to point out today, discussions we've had about, and there are a number of different evacuation scenarios. You can take any given tall building and probably develop a dozen different evacuation scenarios. But what I wanted to show you here today is just for example, to try to understand what some of the issues might be with refuge floors. So we have a fire that occurs in one area of the floor. The typical response might be to order an evacuation of the floor above, the floor below, and the fire floor, and then we would let those people evacuate through the stairs out of the building, and yet let everybody else remain in the building. Or maybe this fire continues to grow in size, and perhaps then there's a need to move people into a refuge floor. Now, if we really think about what we do to design our tall buildings, we're typically going to have two-hour or better fire resistance floors. We're going to spend a lot of time and money to fire stop any of the mechanicals and protect the vertical shafts that go through these floors, and we're going to have sprinklers in this building too. So is it even really necessary, if we've moved the people out of the immediate zone here and with the two-hour floors, the fire stopping, and the sprinklers in place, is it even necessary to move these people up to a refuge floor? Perhaps not. I would suggest to you that those folks could have stayed in place on their floors where they were. So that's one scenario.

What this shows you here is an issue that we see could be problematic. This is an evacuation model where people are filtering down the stairs and they're coming into a large refuge floor and they're trying to use the elevators on this floor. What's happened? People come out of the stair, they come into the refuge area, and then they go back in the stair. But you can see with a potential crowding condition here, you'll see elevators rising up and down here at times, but there can be potential crowding conditions developed as people wait for the elevator here. We don't really know a lot about how people might use these floors. So this is just one illustration of what could happen. Will this happen in this manner? I can't say that it will, but it's something that we see in the models that can be an issue depending on how the floors are arranged and they're being used and what their purposes are. Maybe it would have been better to not have a refuge floor here and let everybody stay in the protected stairway and just continue to exit through the building, or maybe stay on the floor where they were.

Here's a second scenario, where we have a fire located on the floor immediately below a refuge floor in the building. In this case, we would say let's evacuate two floors because our refuge floor is empty already. But a good concern I have is, how are all these people being trained and thinking in the evacuation process? What do they need to do and what are they being told to do? Are they being told, 'We have an emergency event, please go to the refuge floor,' because then after we evacuate the two near floors and we have that zone, is it really fair to say, 'Well, let's move you down right into the refuge floor even though it is supposedly a protected space'? Do we need to move those folks into their refuge floor right above the fire? I would say my suggestion would be that it would have been better to have just left this population on the floors where they were in the building. So the question is, how are you using these refuge floors? What are people's perceptions about these refuge floors? How will they really use them? My understanding from talking to a number of people here in a number of buildings here in Asia is that people kind of ignore the refuge floors and they don't really use them. That is feedback that I am getting from people on our Fire Safety Working Group.

One of the things I mentioned earlier was the various codes. We see one thing is there's a wide variation among the various codes we're looking at. We have collected the requirements from the codes from a number of various countries. Here's just for example a listing of a few. In Korea, when are refuge floors required? Refuge floors are required when you hit 50 stories. In Hong Kong, their rules say 25 stories in height. In Saudi Arabia, 30 stories. In India, it starts when the building hits 24 meters in height. That's when they're required. Then there are issues related to differences in implementation. There's a lot of variation we see in Asia with how much floor area do you really have to use and make available for this refuge floor concept. In Hong Kong, we see that they like to have 50% of the total gross floor area. In Korea, they like to have as much as they can, as near to 100% of the floor area, although they do have room allowance for mechanical areas. In India, they do use a different approach of calculating either having 15 square meters of area on every floor or calculating it based on population. In Saudi Arabia, we see that they like to have dedicated floor areas, the entire floor, every 20 floors in the building.

What else do we want to talk about? Refuge too. I think Fang mentioned earlier about helicopter landing here in China and the Chinese requirements. But we know that some people like to look at the roofs as refuge areas too. Some authorities we know have a strong desire, if not requirements, to see the roof being used in evacuation zone. However, others see this as a very high-risk strategy. Let's take a look at a little example here. Here we are in Shanghai, back in November of 2010. This was a 28-story apartment building. There were a number of factors in this fire: there was exterior scaffolding and welding, and also contributing factors from polyurethane foam and exterior wall construction. But this fire was a serious fire that resulted in 58 deaths. If you looked, going through Wikipedia and trying to find some reference, we saw that the roof was not a good place to want to move people to. If you look at the pictures, they did try to implement helicopters to assist in this, but as the reports indicate, the helicopters were prevented by thick smoke from really approaching this building. Again, this is a situation where helicopters may not be good. What we see when we look at rooftop refuge and helicopters too, I think we have to take into consideration the issues of flight safety. We have the issues of the impact of weather on flight on any given day there might be an incident, but we also, as we can see from the Shanghai fire, the issues of turbulence and operating a helicopter in the zone of a large fire. Also, helicopter flight operations are very tricky, risky operations. Certainly occupants on the roof, we don't want to put them on the roof and expose them to undue heat and smoke. But this is equally important: do we want to really take on the risk and the potential consequences of a helicopter crash in an urban setting? Other things that are concerns of our group for helicopters is what's the time really required to land a helicopter, load, disembark, take these people, and get back to the roof? It's really not an efficient way to deal with trying to evacuate people, particularly any large groups of people.

This slide is why I go back to some of my earlier slides about saying if we have a fully sprinklered building, maybe we need not be so concerned. These are buildings that were not fully sprinklered. This was not a fully sprinklered building. Both of these buildings burned for on the order of 11 to 18 hours, and the fire department actually suspended and abandoned operations at the buildings. Certainly for One Meridian Plaza, they did. This is a building that is in Caracas, Venezuela. This was a fully sprinklered building, but what happened here is, and this is where we need to really pay attention to the sprinkler systems we have in our buildings, because not only are they very effective systems, but they're very critical to preventing this. What happened here was they had a type of sprinkler technology that were on/off sprinklers. On/off sprinklers back in the 70s, they installed them, and these on/off sprinklers started to leak. So what did they do? Instead of fixing it, they just shut down the sprinkler systems in the building. So this building burned for a long time. Certainly, if you look at this, even if we have refuge floors in buildings, even if we have pressurized stairs in buildings, if we have an event like this, the pressurized stairs and the refuge areas are likely not going to be able to deal with the volume of smoke and fire production in these types of events. So the point I like to make here is that we need to pay very, very particular attention to the sprinkler systems we put in our buildings and maintain and test them on a regular basis to ensure that they can be reliable.

With that, what are we doing? Our CTBUH working group is moving to create a document that talks about all these issues. Some of the conclusions that we are coming to are the fact that we think if you have a fully sprinklered building, most if not all floors can serve as refuge space. Also, if you're going to institute refuge floors in buildings, can we, in terms of the financial model and sustainability of tall buildings, maybe have some kind of use for those spaces rather than them sitting there as empty shells? Certainly, buildings with bridges and horizontal connections reduce our reliance on or need for refuge floors in buildings. Rather than taking up the real estate in the tall buildings, what we think is more important to do is take the cost savings by not putting refuge floors in the buildings and focus on sprinkler system reliability, testing, and maintenance. Put your money to that because if the sprinkler can be like the on-demand firefighter there to take care of that fire and put it out, we will not run into these types of issues. And of course, there are property tax and zoning issues.

One of the final notes or thoughts I wanted to leave you with today is, I came across information this week. One of my colleagues explained to me that in Shanghai, there are at least a thousand buildings over 100 meters tall. So I did a little math. I assumed if every one of those thousand buildings, each building on average had 40 stories, then we would have 40,000 stories. If I provided refuge floors every 20 floors, I would have 2,000 refuge floors. Now this building, the Jin Mao Building, we're in, is 88 stories tall. So if you do the math, what I concluded is, if we didn't build all those refuge floors, we could actually build 22 more Jin Mao towers. So think about that from the standpoint of cost, financial viability of tall buildings, and sustainability of tall buildings. That's it.