094 - Experiments that changed fire science pt. 5 - Compartment fires at NBS with James Quintiere
In the fifth episode of mini-series 'Experiments that changed fire science' we cover the compartment fire experimental campaigns carried at NBS (now NIST) in 1970's and 1980's, with the maybe most famous of them all - the Steckler's room experiment. My guest - prof. James Quintiere touches on the experimental design, design choices and most importantly - the technology available to measure and how they made it work.
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Hello, everybody. Welcome to Fire Science Show. If you follow last week's episode, you know exactly what's about to happen. I have interviewed professor James Quintiere on the us fire movement and the development of fire science in seventies and eighties in us and collaborations worldwide. It was quite fun. albeit the little, a bittersweet. With, uh, the politics involved and reasons why. The golden era of fire science has ended actually in there. Anyway today, we're coming back to these glorious times, but with a more technical approach. So I have interviewed James for another hour for about, uh, technicalities of research carried at NBS or NIST now. How this experiments were planned, how they choose the topics. Uh, who was involved, how they measured stuff, actually, that's, that's probably the most impressive part of it. How did they measure stuff? And while these guys were advanced in measuring stuff in fire, and so much more careful than many of fire researchers, I know myself, including, It's fascinating and inspiring to learn from James about that. I guess I'll be fine, ending intro as it is now, because I think I need to recommend listening to James Quintiere talking about some of the most impactful fire experiments ever conducted in history. So, yeah, let's spin the intro and jump i into the episodes. It's been two months since I've received a professional support from my sponsor, OFR Consultants. And I must tell you it's really helpful. And really helps me create the episodes, like the one you're about to hear. So I would like to express my huge gratitude to all four consultants for being a pattern of the show. If you had no chance to learn about them yet OFR Consultants is a multi award winning independent consultancy in UK dedicated to addressing fire safety challenges. It's UKs leading fire risk consultancy, and OFRs globally established team has developed a reputation for preeminent fire engineering expertise with colleagues working across the globe to protect people, property environment. OFR is always looking to grow its, and it's always keen to hear from industry professionals, who'd like to collaborate with them on fire safety futures this year. If you're one of such people. Get in touch@overconsultants.com. And if you're an academic looking up for stipends and scholarships that are being funded at major universities across UK. You can also reach out to them. OFR thank you so much for being a patron of this show and helping me create this content free for everyone. And now back to the experiments that changed fire science with James Quintiere.
Wojciech Wegrzynski:hello everybody. Welcome to Fire Science Show. I'm today again with Professor James Quintiere hello, James. Nice to have you here
James Quintiere:again. yes. Thank you. Thank you, Che. Really,
Wojciech Wegrzynski:really happy that you've, uh, to continue our interview. Last time, we were talking a lot about the history of the US Fire Movement, how many things were put into the place, the politics that did not help that much, and sometimes, uh, made destruction to the efforts of fire scientists. However, when we're discussing the mid seventies and your early days at there has been a lot of great fire science and experiments, and that's what I would like to cover in this part of the podcast. So, first, like, if you can, tell me, uh, what sorts of experiments were the ones that were most interesting for you happening in seventies, mid seventies, early
James Quintiere:eighties? Well, uh, I'm the kind of person that sees the big picture, so I would say almost all of them All of them. with, uh, uh, physics instead of chemistry. If it, dealt with flame retardants or maybe smoked particles or something like that. Hmm. didn't attract my attention as much as, flame spray and, the motion of, fluid in fire, pool fires, uh, fires in compartments. so all of that kind of attracted. and I think I spread my career over working in bits and pieces of territory.
Wojciech Wegrzynski:Well, uh, I struggle to call them bits and pieces because in your scientific curriculum, there is so many fundamental, papers and, and stuff that's absolutely fundamental to our modern understanding of fire. Calling them bits, uh, is maybe, uh,
James Quintiere:Well, enabled me and en and encouraged me to write a book to put that together and to try to, uh, create the book in terms of the bits and pieces, but to make it unified in a way. So the style of my book is more like a book on heat transfer or fluid mechanics, which tried to integrate the subject so that. Flame spread is not distinct from a fire plume There's things that are in common and it's becomes part of the same discipline of fire behavior. And so fire behavior, I think was the key attract to, to me, and fires and buildings and, uh, the most of the research at that time, either at NIST or in the academic field, and I would say most of it was in the academic field, focused in that territory. So they were looking at ignition flame spread, how things burn, what's the real science ingredients of a test method. Fires in compartments. Um, what happens when a flame hits a wall, when it hits a ceiling? why are laminate flames different than turbulent flames? So all of that came into a perspective for people to work on because nist assembled three groups in fire into one, Mm-hmm. and they brought in the research activity of the National Science Foundation, which was academia. Hmm. all of that came together and it came together under, the fire directorship of John Lyons. and people started thinking about all those bits and pieces. there were bits and pieces and the integration of them, was not considered. It was just, let's look at each individual piece. And when you look at pieces, what people do first is Let's burn something let's try to figure out what's going on. and so that was the really, the approach that people made those, uh, 1970s
Wojciech Wegrzynski:And, and I assume then you suddenly realize this, all these things intertwined together, one leads to another. You cannot consider flashover without understanding the, ignition of, of a solid
James Quintiere:surface, right? yes. I mean, you need to understand buoyancy. You need to understand heat transfer, flute mechanics, and then you, you need to understand how combustion comes into play in that. and one person we haven't mentioned is Brian Spalding. Brian Spalding in his early work, tried to look at combustion problems, in an engineering framework. In his later years, he moved to C F D because he felt that there was limitations, rightly so. you know, you've probably heard of the B number and the formulation of how things burn in terms of number Hmm. Schwab, Zeldovitch, in how you can make the equations of mass and heat transfer, assemble into one. And so that foundation was there from Spalding and Zel that allowed fire scientists to tap into. So that was an analytical tool that they could use. But really to look at this for the first time that many people were just stepping into it, they, they had to figure out what to look at, how to look at it. Uh, I could remember early scientists making measurements of temperature or velocity, and they were incorrect because they didn't understand that a thermocouple could have errors or that you were measuring velocity so low that, know, their instrument wasn't capable. there were a lot of challenges like, like that. and, bringing all of that together at N B S a catalyst.
Wojciech Wegrzynski:you've mentioned analytical tools that existed, What was the state of computational fire science at that point? Was it already the times where Howard Emmons had this first, code produced?
James Quintiere:No,
Wojciech Wegrzynski:No.
James Quintiere:no. The Howard Emmonds code grew out of the work, the early work in the seventies, in which, like even Howard Emmonds himself, he, he would have students, he had one student before all of this came together. Look at how Wood Cribs Mm-hmm. and expanded the work of Dan Gross Robertson from NBS and brought a theory into play. Emmons had John de Ris work on on Flame. and get, almost an exact solution for flame spread. Emmons worked uh, a fire whirl which was a phenomena not understood. Emmons had, Frank Tamanini work on, um, extinguishment of, fires. and then at the same time at FM was work going on on pool fires, uh, Modac. So people were focused on all of this. And there was an collaboration of the work between FM and Harvard. That program was linked. It was funded in as a link from NBS it wasn't funded to Harvard and to fm. It was funded. To Harvard and FM as a single entity. And because they had all these pieces, they decided they should put it together in a compartment fire. Okay, they, had a whole series of compartment fires with the best instrumentation unravel what was going on in the different pieces. And that led to Emmons, concept of a zone model.
Wojciech Wegrzynski:fantastic. And, and what was the understanding of the smoke dynamics at that point? The, the fire plumes, entrainment the
James Quintiere:layers. first of all, I think the smoke layer and the idea that you would have such a stratified Hmm atmosphere was something that was a revelation had to be probed. hmm. but because there was this focus on fire, many people recognized it. So Tanaka in Japan recognized it, and he could make his own model. Uh, people at, Illinois Institute of Technology, they got a grant from the National Science Foundation, and they could conceive of this, Emmons could conceive of it. I, I could do my little experiments in a compartment start to see this, Hmm. so I could form the basis of a system model that said, you have an upper layer, you have a lower layer, and you have flow through an opening. Let's conceive of the model in those terms, and now let's proceed to figure out how you get the flow in and out. what is the fire plume doing and build from there. And so this idea of a zone model came in several places because of the dynamic and interaction I think of the work.
Wojciech Wegrzynski:if you look the zones, the, i I think the distinguishment between the, the hot smoke zone and, and the free zone, you can observe that, you know, but wh when did you realize that the assumption that the, the hot zone can be considered as something, uh, unified, like, uh, How did you probe that? How did you
James Quintiere:validate that? well, in the work with Steckler, used aspirated thermocouple probes, which were first used I think at fm. Mm-hmm. to try to eliminate radiation effects. At the same time, work was going on, at, Caltech, under Ed Zukowski, and he would measure very carefully that temperature profile, in, uh, a room fire. And he would measure the gas profile and he would show, uh, how uniform, Hmm. was. of course, if you have a large room, like a corridor, like room, then it's going to vary as you move away from the fire. as a first approximation, the, that's what you have. And in that sense, Howard Emms was the last thing he was trying to work on was how to extend a room to a corridor like, enclosure. So you could allow for the, in the zone model, the variation in temperature longitudinally along the corridor. So there was, there was work trying to extend that, but there's really no need to do that when you realize that Tanaka applied his zone model to the World Trade Center after the bombing. And he modeled the smoke movement in the entire World Trade Center Hmm, with his own, with his own model. and Tanaka has built in wind effects. He's built in mixing effects between the layers that Ed Zukowski illuminated really. research. so the zone model concept came out of that, catalyst of interaction. and people watching, you know, like you said, you could see it, And so, it's like from an engineering point of view, Hey, let's model this as one zone and another zone. And they interact, they interact through the plume and they interact, through mixing. And they also interact because, when the lower wall gets hot, heat goes, the hot gases move up along that wall, Hmm. and then they encounter a hotter layer. So now they can't penetrate and they blur out the zone between the hot and cold layer. And there was research going on on that. So those things could be embedded into a zone model as secondary. Phenomenal.
Wojciech Wegrzynski:just like plume model is, is is also embedded as
James Quintiere:embedded. but of course when you embedded, you don't have the effect of coming in from one side knocking the plume mm-hmm. in the zone model, the plume stands up straight. But in a CF D model, the plume will bend over because it will, yield to that fluid of mechanics. and might do the mixing too, but it might not because that's a viscous, turbulent effect.
Wojciech Wegrzynski:So when designing experiments, to see inside the layers, what kind of tools you had available? You said, aspirating, thermal, uh, couples. That's, that, that I guess is quite advanced. Uh, what, what was your options for, for example, measuring heat fluxes? You, you had water called gouges at
James Quintiere:that point. Y Yes. there were these companies like Mether, Hmm whose founder actually had a PhD from who developed, thermopile type heat flux sensors. There's also a gourdon guide type hmm. a guard type heat flex sensor is a, a thin piece of metal in which you measure the center and the edge. And that difference corresponds to the heat flux that's received. thermo pile actually acts like a, it is a thin layer, but it has, the ability to measure temperature difference across that thin layer and from the conduction through it. uh, you can get the heat flux and the thermo pile one is far superior. The guard on gauge has some, uh, problems with it. So, people would use these and there would be issues of, Jorge, it's water cooled. You're putting it in a wall that's hot. Now you have a flow coming along and it sees this cold thing, and then suddenly it sees a hot thing again. And so there's issues of heat transfer, fluid mechanics of how to really interpret that gauge. mm-hmm. People were struggling with that. I think people forgot that today,
Wojciech Wegrzynski:And, uh, devices like we used today, like plate thermometers or thin skin color meters. They, they were not available.
James Quintiere:thermometer is Thermo couple. Yeah. type gauge. not the guard on gauge. It's actually measuring it. It's, you know, Wickstrom, promoted this thing. but it, it's been there for a long time and it can give you, uh, results. and so I, I've used that on occasion too. but to me, I think the, the, uh, thermo pile gauge is probably the best. The issues with those gauges is that need to make sure you know, the emissivity of the surface and the surface doesn't get cor fouled up during your experiment. In addition, if you try to separate out radiation, you put a window over it Mm-hmm. and the window is now transparent, but not completely to radiation. So you have that issue. you try to blow air over the window to keep soot from coming in, but it deposits anyway. So there are still issues with those, gauges. very fundamental issue that I don't think has been resolved, and maybe ISOs tried to do this, but I don't think they succeeded, to figure out how, how to find a way to calibrate these gauges.
Wojciech Wegrzynski:we, we still think about that, you know,
James Quintiere:You think about it and you don't have a way to do it. And when I was at NIST there are ways to do it. There's, there's improved techniques. There's a, device called a ellipsoidal, radiometer that has uh, gold surfaces in an ellipse. And you one focal point of the ellipse where the. the stuff enters and the other fo focal point, you have a sensor. Hmm. and the gold allows you to capture everything that comes in, uh, between the two focal points and you blow air through this thing. So you're always, blowing the smoke away. So you will always get the radiation that comes in. And that's an expensive, tool. If you go to Med Tham these days, the current guy that's operating that, he, he also has a PhD from M I t and I think he has a good understanding of these gauges. don't tell you how they calibrate them, but they probably have a black body someplace. And in my days at NIST in the seventies, I went to the people who did. radiometry measurements for light and things like that at mbs. So they were very accomplished and understood, uh, spectral aspects and emmis civilities, and they calibrated, uh, thermo pile gauge for me that I bought for mether, and they calibrated it up to, I think, I don't know, maybe two, kilowatts per meter squared. They couldn't go beyond, they couldn't go beyond the certain, so they, they, they calibrated two of these for me, and then I inherited a, a light source that gave me ability to get to a hundred kilowatts per meter squared. And so as, as long as I had a paint on this sensor, That was an emmis of one, Mm-hmm. did, I I, there was a special paint that gave you an emissivity of like 0.98. Mm-hmm. I had these two things calibrated, and although they were calibrated at a low heat flux, we could show that the thermo pile gauge works in a linear way. Interesting. Yeah. So if, if you go to higher heat flux, it's linear here, and you, you could show that, scientifically, uh, from the theory of that gauge. so we developed, this technique and it stays at NIST to this day. However, after I left nist, they lost one of the sensors and, they used the sensor. To give to anyone in the cone that wants to calibrate their cone. And so this sensor that is supposed to be in a lockbox is distributed to people to use. Now, when you, when you have a calibration source, you've developed transfer standards. So people haven't done that. the FAA, I've done work here, uh, I'm in New Jersey right now. they went to med and they got assurances that they would get the right so in recent years, I took the sensor I had, which came from nist, you know, traceable to NIST and That was traceable to mem. they were within 5%. So that's the kind of confidence level I have today in those sensors. I do think that a lot of people should pay attention to how they calibrate them.
Wojciech Wegrzynski:uh, that's astonishing. Like, uh, it, it seems you may even, like, you definitely had a higher comprehension of,
James Quintiere:of this, well, we worried about stuff like that in those days. Like Bernie McCaffrey wondered what's the best way to measure
Wojciech Wegrzynski:that, that was my next question, like,
James Quintiere:he, he said I could do it with a Pitot tube I know a pitot tube is, now it, if he did it with a hot wire and put it in a fire plume, Mm-hmm. it may not survive. Mm-hmm. the error that you would get from the so collection or the buoyancy effect on, on the thing There would be problems. So went to the pitot tube, but then later on he went to the bidirectional probe, particularly if we looked at doorway flows, because Heskestad developed that. And if he wanted to measure a doorway flow, didn't want to take a, have two pito tubes there. Yeah. made the bidirectional probe, which works on the same principle as the Pito tube, in place of two pito tubes in different directions,
Wojciech Wegrzynski:So, so to give a better context to listeners. So we are here talking about compartment fire dynamics. We just said that you had two layers. We've discussed how temperatures were measured in layers. The second, next most important thing is the opening at which the exchange of mass between the compartment and exterior happens. So you really need to very precisely quantify the flow in and flow out in both in terms of temperatures and terms of, the volumetric, uh, flows. So, so that's a challenging measurement even today. And I think, what you are now describing the bidirectional probe is still the, the standard, uh,
James Quintiere:approach. it is a way to do it, but at that time period, Hmm, like Bernie McCaffrey said, okay, uh, Heskes that developed this, h how does it work compared to the pido tube? hmm. what, uh, coefficient do I need for this bidirectional probe? how is it affected by the angle of the flow the direction of the velocity if it doesn't hit it straight on? And so people were concerned about that because if you put this thing in a doorway flow, you see right away that if flow is coming out, the flow goes down over the soften and then goes back up again. you, you have that probe now in a way where the flow is actually changing direction very strongly. And so is it measuring the, the flow accurately then? And so we looked at all those issues know, and Ed Zukowski was another guy that took pains to make sure he had the right measurements. and so measurement techniques were important and their validity, based on how they're calibrated or how, how they should be interpreted?
Wojciech Wegrzynski:were the experiments on the ceiling jets also carried at NIST at that time?
James Quintiere:Oh, the ceiling jet was done. it was probably motivated by John gave Ron Alper, uh, his, of baptism into fire by working on the ceiling jet. and so Ron, cobbled together, an analysis of a plume to the jet. And, there's been, you know, uh, work on it since. But, even Spalding said to me one time, he says, the jet will re Lamin rice. and so these are still issues that people haven't fully looked, looked at. one thing from the ceiling jet work that Ron Albert did is very useful for fire investigators or fire And that is that a kind of a useful, simple rule that comes out of the ceiling. Jet is the ceiling jet takes up 10% of the room height. So if you don't have a sprinkler or a detector in that region, they're the ceiling of 10%. It's not going to work. Yeah. very useful stuff came out of Ron Oh. But if you go to extend that and try to extend it to flame length under a ceiling, there's still work that needs to be done. and that work stopped?
Wojciech Wegrzynski:how about entrainment? McCaffrey did experiments on, on fire plumes within an immense amount of different fire plumes. How, how was, how was entrainment captured
James Quintiere:by you when in from McCaffrey measurements, he measured the distribution in a plume. of velocity? he, he measured the velocity across the radius Okay. different heights. if he, if he did that, he got the temperature and velocity over that radius, then he could integrate that and get mass Mm-hmm. However, at the edges, he had big, hes so, he did not put a lot of faith in his entrainment interpretation from those measurements.
Wojciech Wegrzynski:Don't tell me that my whole career is on that, on this equation.
James Quintiere:The entrainment work, the good entrainment work comes from Ed Zukowski and Byler picked it up as a, another student with Emmons. Ed Zokowski conceived of this thing that if you have a hood Mm-hmm. and you're extracting gases from it, and you put a fire plume below it, the fire plume will go and fill the hood and some will spill over. Mm-hmm. . Okay. Uh, but if you contain that fire plume in the hood and you don't get any spillover, essentially the, the plume is going into that layer. And the flow is coming out the top. And so if you vary the height of the, the flame, you could get entrainment at different levels in the flame by that, ture type, technique. and so Zukowski that showed that, that could be an accurate way of making the measurement. And then Byler and other people probably picked it up. But the best measurements come from, Zukowski. Fantastic. I think in zukowski did it at different sizes. All right. some people do it for a point source, Mm-hmm. can't work for a point source. You have to, get some measurements and then extrapolate it to a virtual origin and do things like that. But Zukowski measurements of different sizes. And again, if you try to take in the effective size, you can get an equation that covers most of the data. And I think it's in my book someplace. We, one of my students helped, integrate all of that data. but, there still needs to be work done there because, you have a big pool fire. A big pool. Fire is basically laminar at the base. So its entrainment is totally different than after you get beyond that region. Now is, if FDS is, giving you the answer to all of that, is it good in that lamina range as well as in the turbulent range? I don't know. Hmm. So those problems still are out there And because you people use C f D, think they got it all already when, they may not. That's the. before CF d you, you would focus on the experiment and you say, look, what's happening down there at the bottom? That's laminar, but I'm analyzing this as a turbulent plume. How can my my answer be right down at the bottom? and so that's, swept away. Now,
Wojciech Wegrzynski:Very, very
James Quintiere:interesting. You CF d prevents us from looking there because we say, look, we, we got it down there. It looks laminate.
Wojciech Wegrzynski:the lack of, um, of full scale research, uh, is, is
James Quintiere:full scale. You could do work on a, okay. spread on a napkin and, and still not fully understand it
Wojciech Wegrzynski:That's, a challenging,
James Quintiere:well. Well, I mean, you go to the work of flame spread, right? hmm. Concurrent flame spread is still complicated because it involves turbulent and radiation from that. but a post flow flame spread is more simple because it's a very kind of stable laminate flame moving, moving along. Fernandez when you, hopefully you'll interview him and he could give you the history of that and how they, they had to include, oxygen effects and velocity effects at the leading edge, in terms of a Damkohler number. Mm-hmm. And, and, and so w work like that was going on, but then it stopped.
Wojciech Wegrzynski:We got safety. We got everything
James Quintiere:now. I, I don't know, but you know, upward flame spread is still, upward burning. Mm-hmm. people I saw that did upward burning. To match experiments done at FM Global and by Jerry Faith are the using the, fire foam code from, uh, FM Global, uh, uh, Ning Ren and, ye I mean they produce good results, but they had to get that turbulent boundary layer working, Hmm. and I'm still not sure how NIST handles that.
Wojciech Wegrzynski:Now to go back to the experimental design, I think at some point of the interview you've, uh, you've referred to them as box buildings. Uh, so, uh, how you constructing them. How are you choosing like the configurations to, to go where you're starting with a very simple configuration of a compartment corridor mixing them. What was the logic behind that?
James Quintiere:Well, it, again, these things were motivated by c certain things. when I got my feet wet in fire nist, it was looking at these corridor fires involving floor covering Mm-hmm. a room in the
Wojciech Wegrzynski:you said that was an effect of a fire that happened and, and, blocked people.
James Quintiere:Yes, there was a fire in a, nursing home in Pennsylvania. And source of funding at that time was, the housing department in the US government, and they gave a lot of money to NIST to study those fires. So where one side of, uh, NIST and FIRE had money, directly through nist, which would be almost full funding. The other side of the NFI program needed to rely on projects like that. And they were able to get some really big, long-term projects, to look at, things like that. So both sides motivated each other. You know, you could see these big fires going on and other people are saying, oh, wow, I never saw that before. Mm-hmm. So we, we were in a learning mode, And we had a lot of stimulation.
Wojciech Wegrzynski:when, um, looking at, uh, that research, correct me if I'm wrong, but I I've, I didn't see any research on vehicle fires. I
James Quintiere:what kind
Wojciech Wegrzynski:vehicle fires Like cars in garage.
James Quintiere:Yeah. Uh, yes. There weren't yes, because at that time the focus was flashover fire tests. How are they doing a good job with materials? they causing flashover? So the, focus was room fires. the, fires in cars only became like, an anecdote when they discovered that the statistics on people dying in car fires, was, off by a factor of 10. And so immediately the, Death rate in fire in the US went from 8,000, a year, to 4,000
Wojciech Wegrzynski:by correcting By by, by correcting the, the vehicle. Okay.
James Quintiere:Yes. And, fires in motor vehicle to give you perspective is 40,000 Mm-hmm. and today the, I think the number might be 4,000 for fire in the US today. So no one worries about fire anymore.
Wojciech Wegrzynski:Well, I, I think now with the electric vehicles, it became a trendy topic again,
James Quintiere:Well, yes, but they'll solve that problem because look, using gasoline in vehicles for over
Wojciech Wegrzynski:which is kind of flammable
James Quintiere:Yes. More worse than the batteries always. They're flammable. The batteries are only going to be a problem if they're, they have a fatal flaw Hmm when they were made or if there's an accident. And the reason is, if you have one go bad, they'll all go bad because the batteries only this big. it's like a a, double A battery Yeah. has thousands of these things in their cars. And. so so they'll figure out a way to prevent it.
Wojciech Wegrzynski:Y your research, this era of research at, at NIST also coincided with, uh, increased use of plastics.
James Quintiere:Yes. that's why the fire service started to say, Hey, we're seeing fires occur a lot faster. We can't get there fast. and somehow they're growing faster. And so people started to say plastics and people started to say test methods. So the focus of this early science research on fires developing fast in a room flashover, how do test methods behave? So a lot of the research was focused on how does the, uh, so-called tunnel test in the US with fire down a, a tunnel like thing with a fire on a ceiling. how is that really working? how does, um, the cup burner work, Hmm. how does Fire on a Rod work? How does the, uh, test for you know, upward spread Hmm. a little material work. So there was focus on those things too. And that's what prompted work on flame spread.
Wojciech Wegrzynski:but you were trying to incorporate that, uh, with the, the full compartment size test, like the time to flash over the spread on a, on a carpet. So, so it was not just the material properties, it was, uh, a full scale physics of the whole compartment
James Quintiere:at fire, right? I think the focus on room fires, yes, flashover was a motivator in what that was. But when people started, modeling the fire, they didn't think they could. Put in all the aspects of fire spread do that correctly. They were still looked at independently, Mm-hmm. some people use FDS to model fire spread in a building today. I mean, you can do that. But there's a, there's a group called, there used to be a, a meeting annually, internationally where people came from all different places to show how they, applied fds. And I think, uh, Kevin McGrattan would cringe when he saw,
Wojciech Wegrzynski:Yeah, I, I, I also have very limited belief in modeling fire spread in fds. There are tricks that you can apply, and simplifications you can make, so it looks realistic
James Quintiere:you you can do it, you can, you can use the code to do that. but the question is, are you getting the right answer? in the. just, just a turbulent burning wall. when I saw fm, do that with their fire foam do that correctly to the data, I was impressed. more like that should be, my opinion, should be, done. I
Wojciech Wegrzynski:completely agree to that,
James Quintiere:you, have worked by Koseki done under Hirano , which are big fires and they show aspects of these big pool fires. I challenge the CFD people to reproduce that data.
Wojciech Wegrzynski:I, I still think even reproducing something as, as simple, if I may, as temperatures in, fire compartments, that's already a challenge. Like, whenever I see a paper that, uh, is a CFD paper and they show me a comparison with experiment, and they show, you know, this perfect, alignment of temperature, uh, between CFD and experiment. I, my first thought is that, that this is either made up or, or, or mistake because it's, it's, it's almost impossible to get this,
James Quintiere:correct. Yeah. maybe, maybe it's, it's not impossible. If you designed the experiment to fit the CFD model, Okay. This way is. designed the experiment, so based on the strengths of the CFD model, then you, you might get good results. I'm not saying CF I'm saying that there's aspects of it that need to be improved, especially for something like fire.
Wojciech Wegrzynski:1 interesting thing about the experiments you've carried at NBS that we're discussing today, today, your experiments, for example, the done, the one done with Steckler about the fires in compartments, but also the, the, corridor compartment experiments. These are staple validation cases for today's models. Have you, was this your intention? Have you foreseen that 40 years later, people will still refer to those as the, validation
James Quintiere:points. No, but I'm, I, I am impressed, with, there were CFD models before fds, uh, some of them out of Imperial College and uh, the Staler. experiments that we did, were basis of, trying to validate those c f D models. And as I said, the last time I had a look at this, this with a student, and we used FDS in the first shot. We didn't get it, get it right, because we stopped the grid at the doorway Hmm. then the students went on further and extended the grid outside the doorway and got some improved results. I forget the details of that, but published someplace. we didn't think it was going to be the b the basis to validate c f D models. It, it was to get a fundamental understanding before that, the only, results that were kind of over a wide range of conditions was done by and Joe Pr which were using water and salt water. So they, they were using water in salt water on a smaller scale. And we, we wanted to look at the, the large scale system and out of the small scale results, showed that as you changed the Reynolds number or something, uh, you got a different, flow coefficient to make the correction and work right. Hmm. And so we wanted to see if that would hold up, in more full scale, realistic. Flow conditions. That was more the motivation to try to, to extend, this work. Emmons did it in a nice, cute way. wanted to see if we could use, that time, the instrumentation that we were using was uh, pressure transducers that allowed us to measure in that low range accurately. And they were expensive. And I think it took me three years before I could buy enough of them to use in St
Wojciech Wegrzynski:H how many was there like, 10, 20.
James Quintiere:we might have had about 10. and then to measure the temperatures, right? we used, work that was done at fm, To investigate the accuracy of aspirated thermo couples where you put a thermocouple in a tube and you suck air over it. So when the, the air comes into that tube, you're measuring really the air temperature, at a high velocity over the thermocouple. if you just put the Therma couple in bear and you have a fire in hot walls, seeing radiation.
Wojciech Wegrzynski:how, how deep is the, the thermocouple into the tube? Is it at the beginning of the tube? Is it, uh, deep into,
James Quintiere:a beginning of, beginning
Wojciech Wegrzynski:so, so it's just a shielded thermocouple that
James Quintiere:aspirates the, good ther couple. Yes. I mean, you could make a Therma couple with a lot of baffles on it too, but then the baffles Hmm,
Wojciech Wegrzynski:okay. And re radiates. Okay.
James Quintiere:then radi radiates. uh, or you could use, you know, different size wires and I think. we tried different techniques and we, we said, oh, this technique is the best. Then. So when we did those experiments, we tried to do it in the best way possible. p tried to align the, bidirectional probes where the flow was going to be horizontal, you know, even though it's Yeah. this. And so we, we did the best, we could. Those experiments were done not on the NIST campus. They were done at a site that NIST inherited from a missile defense site with underground missiles. And so we got a building, on those grounds where we could do this and leave it set up for the whole time. That took some politics too, Hmm. in the missile pits later on, they were doing work on, I think Dave Evans was doing work on ceiling jets because it was a very quiet environment underground. so we, we had this extra, because not, I could not build a full scale room at nist, and if I went to the place where we had the big laboratory, we couldn't exhaust that easily. I mean, so it, it was tricky. So we, we got, know, permission to do these fire experiments, clean fires, and we, can move the, uh, fire plume around so we could show the effect of when you put it in there, a door or an narrow. or, you know, you would get different results. And so it, it was really gratifying work. the technician involved in that. Bill Rankin, lives in, uh, I think Northern Michigan on Lake His heritage is, from Finland and he became very close to Matt Kokola when Matt Kokola came and spent time with us. So in the eighties when I had my group, I invited a lot of people from abroad to come and integrate with our group and, and work. And, Matt Kok has with this guy Bill Rankin, and they did experiments of flames on ceilings that have all kinds of shapes. You, you maybe use, could see pictures of them. Someplace, but they're quite remarkable. And again, I don't think anybody has reproduced them by C f D.
Wojciech Wegrzynski:Beautiful. one thing I wanted to ask you, given the modern technology we got today, my generation of fire experiment, you know, laser velocity, fantastic. color, uh, devices, F T I R spectrometers that you can integrate into your, uh, smoke exhausts
James Quintiere:multi wavelength But, iso, when they were looking at F T R R results for toxicity, laboratories couldn't get consistent measurements. You know, that No, I didn't know that. to the people on a toxicity committee.
Wojciech Wegrzynski:I, I'm, I'm actually, uh, going to have David per soon into the, the podcast. I'll ask him about that.
James Quintiere:I don't think F D I R was current in David Pursers time, but please say hello to him.
Wojciech Wegrzynski:I will, I will. but, but Jim, the, the question is like, if he could like pick one tool of the modern fire science and, and tr try travel it to the eighties, like, uh, what do you think is the coolest thing we, we have now that you struggled with in the past that way Maybe we don't appreciate
James Quintiere:Well, when you mentioned lasers, Yeah. there, are, many ways of the combustion. People have learned how to measure things in flames, Inside?\ The inside flames, even look at, uh, The temperature at points and things like that. So there, there are many type diagnostic techniques that allow you to see things in flames probably people should start applying to fire you,
Wojciech Wegrzynski:you, you have mentioned research like, Prahl and Emmons uh, flows through openings. Uh, that, that's actually one of my favorite research pieces from 1975. Amazing. piece and fundamental piece of research for, for practical, for engineering. Well, yeah.
James Quintiere:saltwater. and again, with, with Steckler, we looked at saltwater, work, later on In fact, my colleague Andre uh, at Maryland when he joined Maryland, he got the salt water tank that I salvaged from this cause they were gonna throw it away. And, he did very fundamental work and he did work on, ceiling jets in which he did it with salt water. And he measured the velocity and, salt concentration so he could relate it to temperature. And that work is quite unique, and advanced for its time. But, it was never, extended. look look at what. Marshall did with salt water on ceiling jets. And that was, that was like an extension of all of this work from the seventies and eighties. And someone like Andre Marshall when he came to Maryland appreciated that. That's why I think the Chinese are going to get into it, because I see papers by young Chinese I see that they're reading the literature very carefully. Now, whether they're supervisor is forcing them to do this they're doing it based on their own, kind of motivation and the resources that exist around them at U S T C, they seem to have a respect and an embracement of, of that work. if they have that and they carry it forward, I see that there's, there's a, a linkage there that improve, fire research through the work in China. I hope we don't go to war before that time. Uh, please
Wojciech Wegrzynski:don't, don't enough politics in, in here. I hope that's not the case ever. Uh, where, where is horrible, what I've meant when I started this. Is this with the
James Quintiere:to study history.
Wojciech Wegrzynski:Of course. but, uh, I, I think there finishing this episode on this, on this beautiful experiments you've you've conducted at NBS that, that were cornerstone for many further achievements of fire science.
James Quintiere:one, one experiment, uh, that I, I didn't mention Okay? work by Jerry Faith on turbulent wall fires. Okay? and he had a student, I think that student passed away early, but, he did work on turbulent wall Mm-hmm. first he did like just hot plumes along the wall. Then he did the laminate fire along the wall. So he did, you know, can I get data for a laminate fire against the Hmm. And how did he make those fires? He made them in a simple way. He wanted to predict the burning rate of those fires. So he used, liquid fuel embedded into the wall where he could then know the evaporation, thermodynamics of that liquid, which is very simple kind of Hmm. You don't have to worry about spiralizing wood. And so if he knew that, he knew the burning rate very, very well. so, they developed a theory for the laminate flame, uh, using B number type Hmm. and they measured the temperature very carefully with, fine thermo couples and the velocity with, I think they used, uh, hot Wire. But they, Jerry Faith was a, a really excellent, mean, he was, he was unbelievable. uh, he was the editor of Combustion in Flame. He was the editor a journal, uh, in Fluid Mechanics. He was, he, he was remarkable person. and so this was very careful work. And then they extended it to the turbulent, field above it, with the same student. And they made the same measurements and they made the same. And they had a turbulent model that they, that they used, and got reasonable predictions even though they realized that there was a lot of radiation in those flames. and they swept that under the rug a little bit. But th that's a, that's a point where someone needs to go further. you see, like the next step would've been, let's see how we could bring in the radiation. Let's see how we could predict it. how is that a function of the fuel were burning? it be generalized? Can we get a simple equation? Or do we have to resort to CFD every time we wanna learn something? those steps never were taken anymore.
Wojciech Wegrzynski:I, I hope there are a lot of young researchers listening who, who, who, who seek their careers.
James Quintiere:Yeah, yeah. Yeah.
Wojciech Wegrzynski:And there is so many experiments that need to either a step further or maybe a revisit with a friendly update in a, uh, in the specs.
James Quintiere:like any field, if you throw money at it, people will do stuff. are not throwing enough money at fire. throwing money at batteries now. But, uh, Hmm. I don't think the industry cares, just like the plastic industry didn't care.
Wojciech Wegrzynski:So fire research fantastic. Was byproduct of, like you said, the the fines they
James Quintiere:got. the use of plastics, uh, was a technological change in the way we live that, enabled fire to develop in different ways. A and so, that was the, the spark really like batteries are now the, the spark that are saying, you know, we should do more fire research in batteries. So there, there will always be new technologies that come about. that will, you know, maybe people will invent fusion with those high temperatures, there will be a lot of fires.
Wojciech Wegrzynski:We'll see. The one thing I've learned after two years of doing this podcast, we create issues in fire quicker than, uh, than we generate solutions and people to who can solve them. So we are not gonna get out of job anywhere soon.
James Quintiere:No, the people in combustion may lose their jobs, but the people in fire will not because, and as I said, as investigators, uh, embrace this and the fire service embraces it, fire research should grow.
Wojciech Wegrzynski:Beautiful. let's end this, uh, episode with this, uh, with this thought. May maybe one more thing I'll, I'll maybe publish it separately. Like if you had a message to young people. Just coming into fire. There's so many young people coming into fire science more than ever before. So many faculties open, so many good places to pursue career in fire.
James Quintiere:Well, it's a stimulating field and it's a field that is rich in un discovery, so you can do a lot to contribute to it. But the reality is, is that I think a lot of young people have graduated through fire research curriculum, but they don't stay in the field the field is not embracing. a shame. If you, if you ask how many fire protection engineering firms hire fire scientists or people who did a, a, maybe a somewhat arcane to them research topic in fire, they won't be the first on their list to hire. Hmm. So, the field is not in need of science. The field is in need of tools to how to solve problems.
Wojciech Wegrzynski:Well, we can use scientists
James Quintiere:to, Yes. And the way that works is like, you know, if somebody says, let's go to the moon and people throw money on that, then, then you figure out how to get off this planet. But as soon as somebody says, who cares about the. you see what happens? mm-hmm. fire is in that vein. it's a drag on the economy. It's not a promotion of economy. so it's not like inventing a new thing and everything takes off. And, and now, now you, you have Silicon Valley, fire degrades from, a commerce and economics. It's a drag. it's a loss. But that's why I said if the fire, service community, the firefighters wake up say we need better tools That is, need science. that may be the savior. Lund is the only program that realizes this, that educates their people and then they go into the fire service. So that is one seed that I haven't seen Grow beyond Lund
Wojciech Wegrzynski:Now I, I, I see James, I see. See some promising seeds. Uh, fire, fire Safety Research Institute, ul, this, I, I really believe,
James Quintiere:I, know, I commend those guys I,
Wojciech Wegrzynski:I, really believe this will, this, this is a thing and yeah, let's well, I hope that your prediction that, uh, the golden era is still in front of us.
James Quintiere:it's there. I mean, look, it took Hottel and Emmons a long time to get, you know, some activity going in fire, so, It's there, is always going to exist on this planet. And the as the need to understand it grows, the science will grow. Fantastic. Thank you very much.
Wojciech Węgrzyński:And that's it. This concludes the whole interview I had with professor James Quintiere. I'm really thankful to James for spending so much time with me and sharing so much of his thoughts about the us fire science, how it developed, how it grown. How it changed over the years and maybe some inspiration in How we can go back to the glorious times of the fire science research. In today's episode, we've talked a lot about how the experiments were carried and I think a good message to everyone listening. The researchers listening is that. Many of those experiments. Are done in Hades. Like 40 years ago and they are still this stable. Cases for validating our models. It's it's astonishing. What long lasting impact you can achieve with carefully planned experiments and. Really well thought out fire science. It's a statement that's very contradictory to the modern science, where you're pushed to get papers published quickly, publish as many as you can, hopefully with high impact factors. Look, this is like the exact opposite end of spectrum. Doing a very carefully planned experiment, maybe taking a year or two, doing that. Publishing a single paper. Which still 40 years later. It's a basis of models. How amazing is that? If I had to choose. Between writing a really, really good. paper that we'll continue making impact in few decades and, and. popping Salemi slices of research. I, I would highly recommend doing the former, I guess this is something we try with our fire science. The ITB. I'm not sure if we always accomplish that, we'll see in a few decades, but, Yeah, that's, that's something I aspire to and I highly. Recommend that to any academic around. And I hope this interview with James, Can serve as an inspiration on how to achieve that. Thank you very much for tuning into the fire science show. And there's more great episodes coming your way. So see here next Wednesday bye!.
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