Ep 111 - Dealing with Fire Risk in Timber Buildings

Adam Jones (00:07):

So, thanks so much for coming on the podcast. David, can you start by telling us a little bit about yourself and your role and what you do with Arup

David Barber (00:15):

Yeah, so I'm primarily and pretty much now all I do is work with mass timber and I've been doing that for probably close to 10 years now, which has been kind of an interesting sort of journey. My background is structures and somewhat structural timber and then the fireside of timber and then have had a lot of work over the years on timber frame blue land buildings, old historic buildings, anything related to timber really. But certainly in the last, I suppose 15 or so years as more and more buildings have started to use glam and then into CLT and at larger and heights and I suppose more and more complicated buildings they've needed people like myself who understand how the fire interacts with the structure and have wanted to look at different solutions, innovative solutions. And so I've been, and some ways quite fortunate to be able to be involved in quite a range of projects and all different countries as well from Europe, Canada, US, Australia countries in Asia.

(01:20):

And yeah, it's been interesting to be able to see how mass timber has grown from the point of view of the number of projects and the spread of it the extent of projects that are going on now I think, which is incredible. And then just the innovation as well to be able to continually see how we are taking very traditional project and turning four twos and four six s or sorry, two to six s into something which is tall and doing some amazing things structurally. So yeah, it's really interesting and my role has just been part of that process

Adam Jones (01:57):

And we're lucky to have you on because not many people have had exposure to all the codes and there's seem to be different approaches around the world, but it seems to be underlying in the same sort of physics, I mean fires fire and at the end of the day timber's, timber. So from your perspective, what are looking at risk as my novice understanding it's all risk is probably the fundamental thing we're trying to address. So how do you approach that from a fire point of view and what are the risks from your perspective?

David Barber (02:25):

Yeah, well I think go back to how you started that. I think code the codes are kind of crazy in some ways and trying to explain it to anybody is difficult. Even people in codes don't understand you how codes are kind of coming out and there's this concert theme you hear and code committee meetings about the whole sausage factory that you know never want to be involved in it and see what's going on. Cause it's a pretty messy process. And I think the positive part is that codes continually are changing and wanting to adopt mass timber and that's driven by the desire for more sustainable buildings. Buildings which aren't so carbon intensive. And there's governments that are making that change. And the issue is that it's always codes are historic documents, people innovate in buildings and then codes kind of catch up and some catch up very slowly and others catch up quite quickly.

(03:13):

And so you see this continual change going on as we continue to innovate with mass timber and it's going rather quickly. And so some countries codes are way behind in other countries, they're actually right up there in some ways a little bit more advanced. And so I think that's really important for everyone to understand as well as that, and I see this all the time as you see architects and developers looking on architectural websites and seeing timber building and saying I want one of those. And it's kind of like, yeah, but your code says you can't stuck at four stories and you can't have 18 stories. And that's a big challenge to be able to overcome that. And I think that's really important because it goes to that aspect of prior risk and life safety risk for people because the codes set the underlying I suppose, level of performance.

(04:01):

And it's the same for all buildings, whether it's a six-story office building constructed of concrete or a 20-story apartment building, constructive steel, concrete or timber. There's an underlying level of fire safety and performance in different countries address that in different ways. Some sprinkles into buildings, some rely on compartmentation, others have both compartmentation and sprinklers and there's history behind those. And we've got to also understand that that fire risk is also very different in relation to the approach to aspects, how people evacuate, attend the fires. And so the structure of a timber building has to fit within the prevailing nature of the codes and the regulations and standards that are there because they've been around for a long time. And then we're bringing this relatively new technology in some ways and it's some ways it's not so new net nowadays depending on the market you're in.

(04:58):

And then what we're doing is we're challenging the code to say we want to build taller and larger buildings with the same material. And so it's a question then how does it fit within that risk? And so in some ways long answer to get around to the point that I think the codes are really important because that sets the performance level and then sometimes in some ways like an eight-story timber building, which sounds kind of not that exciting. An eight-story office building which you can think you can build anywhere, could be very, very acceptable and very easy to build in one location. It would be very, very difficult to build in another location for exactly the same building. As you say, the timber's the same, the fires the same people are the same, all the systems that go into it are relatively same, but that level of risk changes and that perceives the way that the building has to be treated. And so that's a challenge for us. It's a challenge for developers, owners, engineers, everybody to be part of that. Yep.

Adam Jones (05:53):

Yeah, I'll drill down a bit further and this is just coming from a place of curiosity. I see. And there might be some underlying frustration from a personal point of view because it seems to be the same physics, but the international building code seems to be quite far progressed forward and I totally get, we don't want to be moving too fast at the risk of unknown unknowns. And then relative to Australia, it's like there's a big step change it seems in allowance for exposed timber. And I guess the devil's advocate of if we play, we got to make sure that the sustainability and biophilia credentials is balanced against that sort of if it is in encapsulation strategy. So what are Australia relative to the rest of the world? What do you think we're sitting right now?

David Barber (06:43):

Yeah, I mean I'll answer it two ways. First of all personally I think you've got kind of high-rise buildings and low and medium-rise buildings and typically there's a line somewhere in the sand and most codes of where you get to high-rise some it's perfectly delineated and Australia is 25 meters. We kind of have very different requirements above and below 25 meters. And other countries like the US, the IBC, it's 26 meters, it's 85 feet and you have different criteria and a lot of countries are like that. And for me, low and medium-rise buildings, the buildings that were sort of six and seven-story floors, I think one-hour fire rating, 60-minute fire rating, put sprinklers in them, leave all the timber exposed perfectly. I think there is no issue at all buildings like that. And I think we should be exposing the timber and we should be having codes that allow lots of buildings like that to be built because that's the strength of timber is low and medium wise buildings, we want to have all those kind of boring three and four-story office parks built out of timber.

(07:43):

That's where the change is going to occur to have the sustainable buildings we really want, it's in that 2, 3, 4, 5 story range and all those kind of unexciting kind of buildings. That's where the change has to happen. And then for buildings, and I think in some ways that's where Australia should be as well. We should be having those buildings fully exposed timber have sprinklers in them and you can just pretty much, you can have a whole lot of basic standard solutions. Architects can download all the typical details, engineers can easy to price, easy to build, go straight through from a permitting point of view, it's not a trouble. Easy to price, easy to build, very competitive and that's kind of where we want it to be. Anything that's kind of high-rise and there's a different requirements from a code perspective cause it's there, it's more about how does the building do you design the building to allow it to withstand a very extreme fire and still stay structurally you need more engineering, you need more analysis, you need more research to go into a high-rise building and that's where encapsulation becomes part of the storyline.

(08:50):

How much timber you expose becomes important, the type of building how tall it is. A whole lot of other issues, how protective the beste is pressurization, there's a range of different fire safety measures that go into a high-rise building and I think we should be able to lineate between smaller buildings and having greater fire protection and a lot of it the type of work we need to put into those buildings from an engineering and approval point of view as opposed to low and medium-rise buildings. So we make them very simple to build and have a product which is desirable for the engineering, construction and architecture and developer community to want and becomes a very competitive building against concrete and steel because that's what we want. I'm an advocate of mass timber, I want our buildings to be a lot more carbon positive and we've got to have cones and standards that back that up and that's where I think the change needs to occur.

Adam Jones (09:50):

And you mentioned, so 25 meters Australia, I think you said 26 meters, the IBC. What is that step change? What is the big difference there that goes from low to medium and in terms of risk it's a big step up in terms of when we go to highrise.

David Barber (10:04):

Yeah, I suppose there is a number of items that go with that from a fire point of view and part of it is that a highrise building is you a 10-story building is a high-rise building, I got an 80-story building is a high-rise building and they're very different but from a code perspective they're not actually that different. And so that's part of the issue is we typically don't, some codes actually have a stepped process where you can step through different heights and you sort of gradually make a change in types of fire protection. Certain codes just have a clear line and it's maybe a couple of smaller changes but realistically it's a bit of a line in the sand and that when you talk to people outside of that it doesn't make sense why is a 10-story building the same as a story building But that's the reality and what we are we're facing, that's the history and that's fine, just deal with that.

(10:51):

But part of that is the structure itself. So if we have a high-rise building and we have to design the structure on the basis that even though it's got automatic de detection automatic sprinkler systems within it we have to assume that those systems fail or fail to operate correctly and then we have to assume that the fire brigade actually quite delayed or potentially fully delayed and actually fighting the fire. So the structure has to stand on its own two feet. So we have to ensure that a fire that occurs, which is a pretty extreme fire can grow and burn itself out and the structure still stands. And that's quite a significant goal for any building, whether it's concrete or steel or timber or any sort of material, you've got to go through a process of making sure that your high rose building is a very, very resilient structure.

 

(11:40):

And from a timber perspective that's quite a challenge because simply we haven't done internationally that many high-rise buildings, we've had to go through that process and looked at exposing and I think that's the issue. You can Brock comma's building in British Columbia, it was a very early tall building 18 stories, the decision was made to wrap that with by a board on the basis of getting around that is issue and that was exactly the right decision to make to allow building all of that to be built. And there's others which have been like that where it's made sense to encapsulate or wrap some or most of the timber. So now that there is a lot of push to be able to say well let's try and expose some of that. And I think we've got to be sure of the research that we've got with that, which we've got some really useful amount of research on that. But also be aware of the limitations of that as well and what it does tell us and what it doesn't. And I think that's part of the important part, going back to your questions about fire risk, about knowing what we do know and then knowing where the gaps are and where the limitations are in being able to design tool to timber buildings within those. And that's the important part now and in the future as we continue to research this and continue to look at building those sort of buildings.

Adam Jones (13:01):

And no doubt in this question you could probably go on for three days but there's a lot of nuances in fighters. Fighters on I I'm aware there's a lot of research. What do you see as some of the most fundamentally important research and addressing some of the nuances that we need to find out from say those or hopefully now known unknowns which were previously maybe unknown unknowns?

David Barber (13:23):

Yeah, I think for me and I think importantly is with when you have a lot of exposed timber is that the fire that burns from all the materials which spend all the furnishings and fixtures or anything which sit in the space the timber actually interacts with the fire and so you've got the fire interacting with the timber but if the timber's exposed that timber and the burning of that timber will actually interact with the fire and change the fire. And that doesn't happen with the steel and concrete structure. And so that adds another level of complexity which means that all the methods and correlations we used to have or we currently have for stealing concrete buildings don't work and shouldn't be used for timber buildings. We've got to amend those, change those or have new ones. And so the way we can analyze spaces with exposed timber has to be different.

(14:16):

And then part of that is we've importantly is we've done quite a lot of research looking at somewhere smaller compartments, so like residential type compartments. So sort of 50, 60, 70 sort of square meters up to sort of a hundred square meters of a residential space and had some really, really good research showing how the fires develop in those and understanding how the ventilation in the windows and the type of fuel and the type of materials, the type of CLT and glue lamp can burn up in those spaces. And that's really, really helpful. So we've got some really good information on residential spaces. What we don't have is really good information on large spaces and large compartments and we have methodo methods and methodologies for large open spaces where we've got steel and concrete and we have method to be able to understand how the fires burn within those.

(15:07):

But that doesn't apply and isn't really valid where we've got the timber because the timber changes the fire. And so that's the area where we need to do more work on. And it's important I think for us to be able to understand the limitations of what we know in those large spaces where we do have the timber exposed because it changes the fire, it changes the way the fire sort of grows through the space and also the way it comes out of the windows, which is important because that's potentially important for vertical fire spread and also changes the way we think about the way that the actual structure interacts with the fire. Especially things like timber columns that are really important as well. So there's continue to be good research but there's also some gaps. And so that's where, from our point of view, we are being very cautious about how we design pool buildings with large open spaces, timber being exposed. I think they're the area of the biggest unknown at the moment.

Adam Jones (16:04):

So on that is that, so we got to so speak traveling fire then because there are some buildings I'm aware of it has partial encapsulations. So how would you position encapsulation or something like that to help mitigate this sort of risk?

David Barber (16:19):

And it's an interesting approach because I think there's a certain amount of, part of it is a certain amount of analysis that you can do. There's a certain amount of analysis you can't do because you can't actually know what the right answer is because you know can some ways, as you can mention all the analysis we do is typically based off some form of testing and so that the analysis just has always been, we've done a certain range of tests and we know that within that sort of envelope of tests we can carry out sort of analysis and be confident with it. And then if you go outside that you've got to be a little bit more conservative or do a lot more work to be able to make sure you're getting the right answer. When it comes to the type of exposure and where the exposure is against where it's encapsulated, there is a lot less on that.

(17:03):

And so we've got the ability to understand how that may influence the fire, but we've also got to have the ability to understand where that may have some detrimental effects on the fire. And a good example of that is that in some ways a lot of architects would want, if you said to them you could have half the timber exposed say on the ceiling or the say the CLT, most architects say they'd want it near the windows because people are outside the buildings, they can look into the building and see the timber And generally in some ways there's a lot of meeting rooms and other kind of unexciting spaces around the center of the building and so you know want people to see the timber as they walk towards the windows and so that'll make sense. The issue from my point of view is that if you have the exposed timber near the windows, it actually increases, the flame heights would extend if you have a really, really extreme fire, which basically means you're spreading the fire relatively potentially quicker.

(17:56):

So from a fire point of view you actually want it the other way around. You'd rather have the timber away from the windows and potentially have that as an and take away that influencing factor. So there are fact, there are aspects like that which we know about but we need to understand how that's going to work in a building and also be able to work out whether that's actually going to stack up for the building as well. Because in some ways you've got to be able to balance what's reasonable architecturally and cost-wise but also balance what's going to work from an engineering point of view. Yeah,

Adam Jones (18:27):

I'm interested to get your perspective and I think there's some disagreement in industry who I speak to on this and that's around dealing with structural adequacy. So how you deal with the char rate and what your capacity is of the panel. There's probably one school of thought where you need your in Australia as 1530 path four tests and do a fire test for everything and leave it all to the testing authorities and then you've got the other school of thought leaving it more of a performance based design and maybe passing on a char rates to a structural engineer maybe using the step model and the proper char models around the world. What's your perspective on that? Is there something for say testing laboratories to be making the call or is it something in the scope of a structural engineer with assistance for the fire engineer to treat a adequacy?

David Barber (19:14):

Well, I suppose from my point of view, all the methodo methods of calculation methods are derived from testing. So you've got to have the testing to be able to then have a methodology you can use from a calculation point of view. So we proved the methods are appropriate based on the testing that's been carried out and pretty straightforward from that. And that's no different to any other material that typically you ever test and test a lot. And then at some point people sit on the committee and decide that we test it enough and we can actually publish something, which we can be used by engineers and then we don't have to do so much testing which is exactly the right approach. And we always want to be able to do that because testing is relatively expensive and we want to be able to make sure that buildings are cheaper and efficient to be able to build.

(20:02):

So from my point of view, and this is where it comes back to, if you've got codes and standards that support a certain type of building which allow you to build very easily without having to do any analysis and without having to get people like me involved, you know can just basically pick a whole lot of straight details off and you've got a code compliant building, that's where we want to go. People like me should be doing ourselves out of a job. I don't want to be involved in the design of timber buildings from that point of view should be, they should be easy to build about getting engineers involved from the point of view of having to do performance based analysis. We should be able to say here's the code, here's some standards, you know, tickle these boxes, you do a standards design like you would for steel and concrete and then you can build your six story building and someone can price it, get it built and it's very straightforward.

(20:52):

That's where we should be and that's where we want to be. And then if it's different, if it's complicated, if it's tall, if it's crazy design or whatever, you need to do something different cause it's in the code, you get engineers involved, then you do a whole of analysis and that's where you know need to do something a little bit different. So from my point of view, I think don't think we've, in some ways we've done enough testing of CLT and glue that we shouldn't need to do anymore testing the material unless it's someone who's got something new or innovative or do doing something slightly different. Which I think we still need to, there's ideas of doing a lot of low-grade combination CLT, which I think is really positive. There's people doing all sorts of different size of different timber timbers with CLT to see how, and it's all about how do we use more of the tree in engineered timber, which is great. All those things, slightly innovative need to do more testing to see if a meet the current correlations. But for a standard design we shouldn't need to do that, we should, shouldn't need to test. We should be able to have basic simple methods to be able to engineer it and we shouldn't need to have any sort of performance based design and adolescence. It's a complicated building the tool building something a bit different and that's where we should be working towards and that's where I hope we could get towards.

Adam Jones (22:09):

Yeah, the question, the answer might be my question here a little bit. So if I'm an architect or builder right now and I don't want to reinvent the wheel, what does it say the best path to go down that they know they're going to get the most simple sort of design and compliance pathway to make sure and de-risk the need for fire testing at all and the costs and programmers that might come along with something like that.

David Barber (22:32):

And I think it's being as compliant as possible with appropriate codes and standards. There is a pathway to build a six story office building now within the code, but it means that you've got to put on layer of master board on the timber but you don't need the fire test. And I think in pretty much most countries where unless you're a countries, there's some countries we still, you're stuck at three or four stories for timber buildings mainly where you're slightly tall, there is always a code path to be able to build a timber building. And my philosophy and most projects is that we want to be able to make it as easier to approve as possible. And so you want to be able to go down the path, which is the path of these resistance because the best in the building is one that's actually built rather than the ones which are designed and priced and then don't get built.

(23:16):

They're not good. And there's a lot of those unfortunately which don't get built. So we want to be able to make them easy to price, easy to build, but also of course easy to improve. So the easiest path is you've got, there's fire tested CLT out there there, there's an appropriate standard to assess the timber you've, from a Charing point of view, we've got all the tools you need to be able to build a timber building at the moment up to 25 of most classes, office in residential going to probably be the predominant ones, but obviously assembly, buildings, libraries, whatever you know could do that. Now it's just a question and if you're going to step outside the code, that's when you need people like myself and others to be involved and you need a certain level of performance based engineering and performance solutions to be able to get you around whatever part of the codes you're not meeting.

(24:11):

And that's where the level of complexity jumps up and that's where it becomes more expensive, becomes time timey to get it approved and you've got to go through that process. So to me, if we can, and I do this, I say to people, why don't you just build it to the code? You'll get a building which will be so much simpler to be able to get approved and get built rather than have to go down this path. And we've potentially going to be a lot longer to approve it's peer review, there's potentially appeals or whatever to be able to do that. And it's a difficult process and that's not what we want. The timber buildings kind of goes back to my, we've got to change things and we allow the easy, simple, medium and low-rise buildings to be built in a way which makes them easy to build.

Adam Jones (24:55):

Yeah, fantastic. Well it's been so good speaking to you David, I'll end on a pretty open question for you. It can be on this topic or anything you like. What do you see as the future of timber construction going forward five, 10 years and with a bit of blue sky thinking?

David Barber (25:10):

Well, I would hope, certainly I hope we can build more timber building. That's the first thing. And I would like them to become more efficient and I think they will be. And I think if you look at sort of North America as a market, the US and Canada and then you look at sort of Europe as a whole, market codes are changing to support master whether there's more production, which has been really important from a timber supply point of view. And as in some ways it seems just to supply demand on supply for timber can't keep up. The more we supply the more the demand grows. And that's really, I think important and it is kind of one global market for timber supply. And that's I think something which is really interesting because it means we see a certain amount of competition but also a lot of situations where the timber is a lot easier to be able to source than maybe it was five or 10% more than 10 years ago.

(26:01):

So I would like to see the barriers being removed and continually being removed and allows us to build more and more buildings that are normal buildings, but also sort of eight to 10, 12 stories. I think we certainly get to a point where we should be Australian, New Zealand, but also parts of Asia and hopefully in Europe it's starting to move this way as well where maybe it's 10 or 12 stories is online in the sand and where you know can build a timber building. You put in these fire protection measures, you don't need to put a whole lot of in some ways lots of carbon-friendly materials on the outside of a timber and protect it all. And those buildings are easy to build and efficient and that's the change we want to have to be able to, the carbon impact that we have with buildings at the moment. So that's where I'd like it to see it to be and I hope that we will get there, but it does mean changes to regulations and codes and I think the market is willing to support that and I can see that that will actually happen. So yeah, it's important for people like me and others to continue to try and help influence and get codes and regulations changed.

Adam Jones (27:04):

Fantastic. Well it's been so good speaking to you today. David is there, if people want to find out more about yourself and some of the research you've been up to, where should everybody go?

David Barber (27:14):

Oh, I mean feel free to drop you or myself a line. I mean just email me, it's fine. david.barber@arup.com. People do it all the time. My email address isn't too hard to find <laugh> or just drop me a line on LinkedIn or something. I'm always happy to help out and answer questions if I can or point people in into the direction of people who can. So there's a lot of good timber people out there who can provide I think good support and certainly from a timber industry point of view, a lot of I think goodwill of people wanting to be able to make sure that in the buildings can get started and if they've got problems to try and get around those. So yeah, absolutely feel free to

Adam Jones (27:51):

Reach. Fantastic. Also recommend listeners, I think you've got a few on YouTube, which I might have seen before when I was just jumping on the exercise bike and to <laugh> watch something a bit nerdy but <laugh> a few webinars I believe from yourself. So thanks so much for coming on the show, David, it's been a pleasure to be able to speak to you.

David Barber (28:07):

Yeah, thanks very much Adam, and yeah, great, just great to talk with you.