Feb. 11, 2026
238 - Fire Fundamentals pt. 19 - Defining fires in your models
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Welcome to another fire fundamentals episode! Today we dig into how to place a fire in a model so results reflect real physics. From plume inputs to FDS burners, we show where HRRPUA, radiative fraction, and D* make or break smoke your calculations. Things considered in this episode:
• why defining the design HRR is separate from placing the source
• what a flame is and why we cannot resolve its chemistry
• plume models compared by inputs: perimeter, Q, Qc
• entrainment, virtual origin, and effective diameter
• realistic HRRPUA ranges for building-scale fires
• radiative vs convective fractions and why they matter
• zone model linkage to plumes for smoke control
• volumetric smoke and heat sources for CFD: volume, placement, and limits
• fuel-based fires in CFD and oxygen constraints
• growth modeling via area expansion vs flux ramping
• soot yields, heat of combustion, and visibility
• D* and meshing guidance for credible resolution
• why predictive fire spread modelling for design use does not really exist...
Resources, resources!
- G. Vigne et al. "Review and Validation of the current Smoke Plume Entrainment Models for Large-Volume Buildings"
- W. Węgrzyński & M. Konecki "Influence of the fire location and the size of a compartment on the heat and smoke flow out of the compartment" - (this is a paper from my PhD where I explain the concept of volumetric heat source)
- M. Bonner et al. "Visual Fire Power: An Algorithm for Measuring Heat Release Rate of Visible Flames in Camera Footage, with Applications in Facade Fire Experiments"
- Episode 100 - Smoke plumes! That was a fun one.
- G. Heskestad "Fire Plumes, Flame Height, and Air Entrainment" from SFPE Handbook (also the source of the overlayed image on the cover showing range at which fires exist)
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The Fire Science Show is produced by the Fire Science Media in collaboration with OFR Consultants. Thank you to the podcast sponsor for their continuous support towards our mission.
00:00 - Why Fire Placement Matters
02:56 - Partner Thanks And Mission
04:36 - Defining The Design Fire
06:35 - What A Flame Really Is
11:02 - Limits Of Detailed Combustion Modeling
13:05 - Consistent Level Of Crudeness
14:37 - Plume Models And Inputs
19:26 - HRR Per Unit Area Boundaries
24:34 - Convective vs Radiative Fractions
27:25 - From Plumes To Zone Models
28:17 - Two CFD Fire Modeling Paths
32:18 - Volumetric Sources: Pitfalls And Placement
36:00 - Fuel-Releasing Fires In CFD And FDS
39:10 - Growing Fires: Area vs Flux Scaling
42:08 - Oxygen Limits, Soot, And Tenability
44:09 - D-Star, Meshing, And Resolution
48:05 - Why Predictive Fire Growth Still Eludes Us
54:04 - Key Lessons And Wrap-Up
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Hello everybody, welcome to the Fire Science Show.
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In today's episode, I wanted to take you somewhere practical, uh, something that is highly relevant to my everyday fire safety engineering.
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Fire safety engineering relies highly on modeling.
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Uh, we're modeling fires, so in those fire models you have to put in some sort of fire, right?
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And uh we all do it like every day.
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We basically model fires, and I'm not sure if everyone reflects on what actually happens when you place a fire in the model, or perhaps rather, how do you correctly place a fire in the model?
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It's not a very trivial question, actually, and I've probably rejected maybe even too many papers, scientific research papers.
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Some of them were quite good, to be honest.
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Papers that shown some physics, some modeling, and in the end, I've noticed that the person done really big mistakes in how they placed fire in the model.
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And that's enough to reject the paper because if your fire model, if you put something that is not really a fire, it makes no sense.
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And the same in your everyday engineering calculations, in your everyday engineering CFD, in your everyday engineering practice.
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I'm pretty sure that if you're trained, fire professional, you do this correctly because we are learned to do it correctly.
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You learn how to do it correctly in your school, in your university, you learn it from online courses, etc.
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Uh so I don't doubt that you are capable of doing it correctly.
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What's interesting is uh is maybe to discover why this particularly is a correct way of doing some things.
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So in this podcast episode, I wanted to share about what does it mean to model fires or to place fire within a fire model.
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And we will discuss a lot of different approaches from plume models to CFD.
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This is the episode where we discuss the HRR per unit areas, convective heat release rates, hits of combustion, fire perimeters, fire areas, etc.
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This this is an episode where we will cover that, and uh to my surprise, I was wondering if I can uh make a whole podcast episode about this.
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It seems kind of trivial, and as usual, I've rambled so long I've run out of time.
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So, yes, there is enough content to fill a whole podcast episode, and I really, really hope it's a good podcast episode, interesting to you, allowing you to reflect on your fire engineering practice.
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And at the end of the episode, I will tell you why predictive fire modeling that uh predicts the growth of the fire for fire safety engineering applications does not exist, which links to everything I have to say earlier in the podcast episode.
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If you're interested, stay with me.
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Let's spin the intro and jump into the episode.
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Welcome to the Fires Show.
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My name is Wojciech Wegrzynski, and I will be your host.
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We've been on this journey together for three years so far, and here it begins the fourth year of collaboration between the Fire Science Show and the OFR.
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So far, we've brought you more than 150 episodes, which translate into nearly 150 hours of educational content available, free, accessible all over the planet without any payrolls, advertisement, or hidden agendas.
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This makes me very proud and I am super thankful to OFR for this long-lasting partnership.
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I'm extremely happy that we've just started the year 4, and I hope there will be many years after that to come.
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So, big thanks OFR for your support to the fire science show and the support to the fire safety community at large that we can deliver together.
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And for you, the listener, if you would like to learn more or perhaps even become a part of OFR, they always have opportunities awaiting.
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Check their website at OFRconsultants.com.
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And now let's head back to the episode.
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So you're a fire engineer brave enough to try and answer some important fire engineering questions that your stakeholder asked.
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How much smoke control do I need?
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What's the temperature of my structure in the fire?
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How bad this fire can be, etc.
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Can people escape my building?
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We usually resort to modeling to answer those fires due to the inherent complexity of the fires themselves.
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Also, for the purpose of this broadcast, I assume you've already got the toughest number to get, which is the size of your fire.
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So you are perfectly aware of how many megawatts of fire will be emitted to the space that you are considering.
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I mean, getting to that point, getting that design fire, it's a struggle on its own and absolutely deserves not only one but more podcast episodes on their own.
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And uh this is something we will talk in the future of the Fire Science Show.
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But today we assume that you are lucky, you have the number, and all is left is to model that.
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Now, uh why I'm recording a podcast episode, why is this something to be discussed?
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Because this is not particularly straightforward, or it is straightforward uh for many people because of the way how they are used to do those things, or you know, because of the general approach demonstrated by their colleagues.
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There are just ways we do things which already went through this logic that I'm gonna present and then provided us with some general guidance and we just do them.
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But we very rarely think about why we are doing them.
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Anyway, before we go into details of how the fires are represented in your CFD software, etc.
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Uh let's perhaps talk about the fire itself or the flames themselves first.
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So what really is a flame?
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I think that this is a very interesting question from the perspective of fire safety engineer.
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What is a fire?
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What's a flame?
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So I like to uh ask this or put a perspective on this question by asking what's inside the fire?
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That's something that when I uh teach people, when I train people uh on on design fires, etc.
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That's one of the questions that I ask.
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What is inside the fire?
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Because you know, we are used uh to this uh image of fire that's in our heads.
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Perhaps you're now imaging a campfire, perhaps you're imaging a pool fire, perhaps you're imaging a fully fledged compartment fire post-flashover venting into the facade.
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No matter what you do, there obviously is a physical thing in that, the the fire it exists, you can see, you can see the shape, the size, the scale of it.
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But inside of it, it's actually hollow, it's empty.
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Well, it's not empty, it's filled with fuel.
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Because the flame is basically a region in space where chemical reactions can occur to create energy out of reacting the fuel and the oxidant, which most commonly would be your air.
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So technically, the flame itself is just the space in which the conditions for those combustion reactions that release energy are pretty much perfect.
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This is the region where you have more or less stoichiometric mixture of your oxidizer and your fuel.
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This is the region where the energy in that volume is more than sufficient for the reactions to happen.
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And this is the region where all the burning processes occur.
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It's not one reaction, it's not two reactions.
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It's kind of interesting when you go deep into chemistry of uh combustion because it's hundreds and hundreds of concurrent chemical reactions happening pretty much at the same time in pretty much the same space.
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And what's interesting, uh which reaction takes place, it's it's kind of a probabilistic distribution.
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Each reaction depending on the oxygen concentration and the concentration of ingredients and the energy or perhaps the temperature at which uh it occurs has its own probability and they kind of compete with each other.
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But eventually the fuel in the perfect conditions will burn off completely, it will and all of this reaction and would end will turn into the products.
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And actually this happens at an extremely narrow space.
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Um why it's so narrow?
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Because for those reactions to happen, you have to have a mixture of this oxidizer and the fuel.
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So there are mixing processes that are happening at a fairly small scale.
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They're driven by by turbulence, by flow, but also mainly by molecular diffusivity.
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And depending on the diffusivity and the reaction rate, you will receive a product of that, which basically means this region of space is the region in which the fuel mixes with your oxidizer, and the time that is available in that mixing is also at the similar time scale as it takes for them to burn off.
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So you end up with with a zone.
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Why I'm bringing that?
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Because the zone is tiny.
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That zone, that that flame sheet would be less than millimeter thick.
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It would be less than 0.1 millimeter thick in many cases.
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It's extremely thin and condensed zone of energy which is wrinkled in the space, it exists within a turbulent motion.
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There are enormous gradients of temperatures existing that cause a very interesting buoyant flow phenomena, turbulent mixing.
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This is constantly moving, the influx of the fuel, the influx of the oxidizer continuously exists.
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So within a space the old fuel is burned down and replaced by new fuel and the mixing continues.
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It's something that happens at a very small scale, and there is an insane abundance of interesting physics that dictate how well those reactants react together and how well in general the thing burns.
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Now do we model that?
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No, we we we compare this is the this is the fun part.
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This if you think about the flame or fire from the perspective of combustion of what it physically is, if you consider it as a combustion reaction between the fuel and oxygen, it it's not something we model in our fire safety engineering.
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Like there exists no single fire safety engineering tool or model other than doing your full scale fire experiments in which this richness of physics would be captured at the scale at which it exists.
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It's simply not possible or not feasible.
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Perhaps you could model a burner or a pool fire with this level of of insight, with this level of capturing the chemistry and turbulence and flows and etc.
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Even for just modeling, you know, a tray of fuel burning, the investment in modeling that would be insane.
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Like it it would this simulation would be more complex than any commercial CFD I've ever delivered for any commercial project.
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So I think we can agree that while we appreciate and understand how complex those phenomena are, we are in a position where we are unable to fully tap into that.
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We we have to model that, we have to simplify it for our practical use.
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And here we come to modeling, here we come to fire models, here we come to fire safety engineering, our everyday job.
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Because we are burdened with answering some very profound questions in our buildings.
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How much smoke will be produced?
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How toxic will it be?
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Will people be able to escape?
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What's the temperature, etc.?
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We need to be able to capture those phenomena at a level which makes sense for the building.
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Now, I also go here because the modeling and the way how you define things in a model for me should be very strictly connected with what the output of the model, what the expected output of the model is.
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Because it's a completely different story when you are interested in general smoke layer height versus when you're interested in perhaps spread of a fire over um solid surface, or maybe you're interested in time to flash over.
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That would be very challenging to model.
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And those models would require you to approach with uh with different tools, and those tools, I'm I'm a huge fan of this term that was uh I think coined in Canterbury, the consistent level of crudeness.
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I mean, if your output is very crude, the models should not be extremely detailed because you gain nothing in this in those details as you lose those details as you get into crude outputs.
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And uh this consistent level of crudeness makes a lot of sense and it's it's a broad engineering guidance that I follow and really like in my engineering.
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And in in fire safe engineering, when you consider fires in your buildings, we have lots of models at different levels of crudeness, starting with zone models, starting with uh your plume models, going into zone models, then venturing to CFD at different levels of complexity.
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And this is the journey that I want to take you in in this fire podcast episode about how we define fires at those different levels of complexities and what factors uh come into play.
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So we'll start with the plume models and build up the complexity.
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So for plume models, I can start in a very safe and secure way by referring you to a paper, uh review and validation of the current smoke plume entrainment models for large volume buildings.
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It's linked in the show notes.
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It was an interesting work done by a Spanish team, crazy Spanish team, who invited me to participate uh in this with them.
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Uh it was Gabriela, Alexis, Candido, Guillermo.
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These guys have done some of the largest fire plume experiments in in the world.
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So it was it was a huge joy to to collaborate with them.
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Anyway, in this paper, we went into the fire plume models that exist in the literature or that are used by fire professionals, and we tried to look into the physics of how they are built and then compare them with some large-scale experiments on how they how well they capture uh fire behavior in a very large scale.
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And the plumes are usually named after their creators, so we have the Thomas Plume, we have Zukosky Plume, we have McCaffrey Plume, we have Haskestad Plume.
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There are more, there's uh Delicatius Plume, there's uh original Morton Plume, the first one I believe.
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Uh there possibly are more plume models than that, but those four I've I've named before are the core ones used in fire safety engineering.
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Plume models are quite interesting because they take as an input the fire, the size of the fire that you have in your building, and give you as an output some of those variables that I've mentioned that are important for us.
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So they would give you the mass flow at a certain height of the building.
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This is the main characteristic that you get out of the plume model.
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You get the mass flow.
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If you get the mass flow and you know how much energy you have released and you have a way to approximate the losses of heat into heat sinks and radiation, you have the mass, you have the energy, you can calculate the temperature.
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So basically, out of this single calculation of the of the plume model, you get some very important data that can guide your decision making regarding the smoke control dimensioning or in general regarding what kind of temperatures you could expect in the space that uh you are considering.
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They take the fire as an input, but they are not unified in the way how they do that.
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And this this is already quite interesting because there are actually three ways the fires across four four models, there are three different ways the fire is input there, and it already reveals a little bit of interesting physics that we have when we try to simplify fires to include them in our models.
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So you can input the fire uh through a property called the perimeter of the fire, which is used in the Thomas model.
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Actually, it's Hinckley's model uh that was derived based on the Thomas model, but we usually refer to that as the Thomas model, and it's very common in uh many standards, especially in UK and Europe.
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So you would put the fire perimeter.
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You have models like Zukoski's plume, where you would put the heat release rate Q in the in the model.
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And you you have uh models like Haskestuds where uh for some of the parameters you would put the convective heat release rate.
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So three different ways to define fires, and there are some some interesting things about that.
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So in terms of of those plume models, what you want to get in the end is the mass flow in your smoke plume.
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I had a smoke plume episode in the podcast as well, it's also should be linked in the show notes.
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To get that mass flow, you need to know how much it changes with height.
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So basically, what is the entrainment rate?
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And the entrainment is a process that happens around the plume.
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It doesn't happen in them in the core of the plume because there's nothing the smoke can mix with if it's surrounded by by other smoke.
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The entrainment happens where the smoke meets your surrounding air.
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So basically around the plume, at the perimeter of the plume, this is where the mixing happens.
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And this this physical dimension, the size at which this happens is quite important.
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You can derive that by calculating the virtual origin of the plume.
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So this is something used by some of those models, where you would assume that the plume is kind of like a reverse triangle, uh standing on its narrowest peak and it just grows in indefinitely uh up, and the the tip of the triangle will usually end up underneath your ground because the fire is larger than a point, so you it has some dimension.
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So you calculate that number, and from that it goes into the entrainment equation, and from that basically the model figures out the physical dimensions of the fire.
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So in the end, you supply the heat release rate to the model.
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Or like in Thomas' equation, you basically supply that.
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You you give the value of the perimeter, how big fire physically is, and that allows you to approximate how much smoke will be produced.
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And those numbers, um when you go into when you use uh the the models which use the virtual origin, there's not that much you can mess up with the definition.
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Because basically you know your number of of Q, you know your heat release rate, uh you calculate the virtual origin.
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So you know where it exists and the model will not allow you to mess it up.
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When you go into the Thomas model, it's different because you have to define perimeter, and perimeter is obviously related to the space in which the fire exists, so so to the area of the fire, if if you consider the fire just as a surface.
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And when you go into that, there are things that can be broken in here.
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Uh because fires are phenomena that exists in very specific range of physical conditions.
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And this applies also to the energy density per unit area.
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We define this parameter in in modeling as heat release rate per unit area HRRPUA.
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You've probably seen that parameter a lot.
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And this is a very critical parameter.
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If this value is too low, then basically you don't have a fire, you don't have those continuous flames existing within the space because the energy density is too low.
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You basically have some sort of heater kind of.
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If you have if this value is too high, then the density of energy contained in a space is way too high for those diffusion processes to happen in a time frame that would allow a fire to exist at At least in the shape that we we know and we expect.
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So for those extremely high energy densities, you got you would go more into phenomena like pre-mixed flames or maybe m maybe some sort of jet fires, you know.
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The fires that are not the types of fires that you would normally be modeling as a part of fire safety engineering tasks.
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So there exist a range of values of this hit release rate per unit area in which it kind of makes sense.
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The fires exist in that space.
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Actually there is a beautiful classical plot in Gunnar Heskestad's chapter of the SFP handbook where he shows different typologies of flames uh related to their dimensionless uh fruit number Q star and the ratio between the height and the diameter of the flames.
00:22:57.680 --> 00:23:05.519
And you can see they all kind of fit or they are plotted in a quite narrow space in which they can exist.
00:23:05.519 --> 00:23:14.799
I I highly recommend reading through the classical material, and I definitely would consider Gunnar's uh chapter in SFP handbook as a classical material on this.
00:23:14.799 --> 00:23:23.599
So for the engineering purposes, let's let's discuss what would be reasonable value for the heat release rate per unit area that kind of makes sense.
00:23:23.599 --> 00:23:32.079
And there's no ultimate answer because this value will one change with your fuels and conditions at which it burns.
00:23:32.079 --> 00:23:53.759
And two, if you have anything that's more complex than a flat surface, then this value is just a statistical approximation because you have some energy emitted in a space and it's just divided by the space that you have, and you're not accounting for the true surface area of your fuel, which is an important consideration actually.
00:23:53.759 --> 00:23:56.559
So what what are reasonable values?
00:23:56.559 --> 00:24:03.599
Um so when we were doing that plume paper, we'd done some calculations using correlating those different plume models.
00:24:03.599 --> 00:24:27.759
And when we took some assumptions of the Thomas Plume model and calculated the sizes of the flames using those assumptions of Heskestat with the virtual origins, etc., we we came out to the value that the minimum point at which the Thomas model in general is physically makes sense or is valid would be around 375 kilowatts per square meter.
00:24:27.759 --> 00:24:36.880
This is where it begins being reasonable and uh in technically it it should be much more than that.
00:24:36.880 --> 00:24:42.799
Uh some researchers have measured H3 straight per unit area in some of those experiments.
00:24:42.799 --> 00:24:49.839
There were experiments done in which those values would be very low, like 220-ish kilowatts per square meter.
00:24:49.839 --> 00:25:03.279
But uh I would say for engineering considerations, the fuels that we expect in buildings, those values around 300-200 kilowatts per square meter are extremely, extremely low.
00:25:03.279 --> 00:25:20.559
When we were doing the comparison between the predictions of the Thomas Plume and our full-scale fire scenario in uh in a very large H room and we were comparing it, how the layer descends in time and how well the steady state is captured by the model.
00:25:20.559 --> 00:25:26.480
We found that the best agreement was slightly above 500 kilowatts per square meter.
00:25:26.480 --> 00:25:29.519
That was where we noted that the agreement is the best.
00:25:29.519 --> 00:25:51.519
There's also a number that is often uh brought up, which is 625 kilowatts per square meter, and I think it it comes from some of the UK standards where this is a value recommended for some of the fires, and I would agree this is quite a reasonable value to be taken uh for a fire.
00:25:51.519 --> 00:25:54.400
On the lower end, but but quite reasonable.
00:25:54.400 --> 00:26:02.559
Um a value that I usually try to not exceed would be around uh 1000 kilowatts per square meter, one megawatt per square meter.
00:26:02.559 --> 00:26:12.720
This is the upper range at which the models, uh the plume models kind of make sense, and this corresponds to to quite a severe fire, to be honest.
00:26:12.720 --> 00:26:25.519
One uh megawatt per square meter is quite a huge energy generation to give you some reference point if you burn uh heptane.
00:26:25.519 --> 00:26:33.440
I know I'm not sure if you ever burn burnt heptane, but heptane is one of the most viciously burning fuels that I've seen in my life.
00:26:33.440 --> 00:26:38.960
It like produces those extremely tall, very narrow uh fire plumes.
00:26:38.960 --> 00:26:40.480
Heptane is crazy.
00:26:40.480 --> 00:26:48.799
And uh and heptane gives you the energy density of maybe two megawatts per square meter, maybe a little more, depends on how big the pool is.
00:26:48.799 --> 00:27:03.039
So I struggle to imagine what would be the fire like if this wall value was higher, if this value could exist in the higher, like five megawatts per square meter.
00:27:03.039 --> 00:27:09.119
What's interesting is that often uh people uh do mistakes with that.
00:27:09.119 --> 00:27:14.079
People sometimes would use very large number of this heat release rate per unit area.
00:27:14.079 --> 00:27:25.759
They would just do one square meter fire source and then just emit whatever amount of fuel they have from that square meter reaching heat release rate per unit area values of I don't know, five megawatts.
00:27:25.759 --> 00:27:36.480
I've seen that in in scientific papers, and those scientific papers unfortunately did not meet their publication because of that.
00:27:36.480 --> 00:27:38.720
It's simply unphysical.
00:27:38.720 --> 00:28:01.680
So you have the perimeter, basically, if you know the heat release rate per unit area, if you need if you know the uh heat release rate that you're emitting, you have the fire area, you have the fire area, you can calculate the diameter of a circle and you can calculate the perimeter of the circle, which has this area, and this is something you can put into that equation.
00:28:01.680 --> 00:28:08.880
I also think that in in the British nomenclature, this is standardized, so there are some values to be placed in that model.
00:28:08.880 --> 00:28:31.519
When you have different bloom models that take heat release rate as an input, it's much simpler because as I said, you have to calculate some parameters based on that heat release rate, so therefore whatever you calculate will correspond to that heat release rate, there's one caveat which is sometimes you put the heat release rate, sometimes you put the convective heat release rate part into the equation.
00:28:31.519 --> 00:28:52.079
The reason you would like to do that is that heat release rate technically is the entirety of the chemical energy released by the flame, by the reactions happening in the flame, while the convective part is basically the part that goes into heating up the air and causing the upward motion of the smoke.
00:28:52.079 --> 00:29:00.240
What's not in the convective part is the radiative part, which is what the fire radiates away from itself.
00:29:00.240 --> 00:29:10.400
Fire is luminous, it's high temperature, there's soot in the flame that creates the very strong emissivity of the flame surface.
00:29:10.400 --> 00:29:17.200
It radiates heat away, and uh a big chunk of energy of the fire is actually radiated away.
00:29:17.200 --> 00:29:20.160
It's uh something we call the radiative fraction.
00:29:20.160 --> 00:29:22.559
It also sometimes is used in CFD.
00:29:22.559 --> 00:29:48.480
You may not even know that you're defining it, but it's an important parameter to tell how much of the heat is immediately radiated by the fire, by the flames, and how much of the heat goes along with the smoke, creating buoyancy effects, promoting entrainment, mixing, and in the end, eventually influencing how much smoke you have in your room and uh how big temperature that uh smoke is at.
00:29:48.480 --> 00:30:02.319
The radiant fraction, um a common value used is between 0.3 and 0.35, uh, dependent if you're using zone models, sometimes for for dependent if you're using plume models or going into advanced modeling.
00:30:02.319 --> 00:30:10.079
For plume models, a typical value would be 0.3, so convective is 0.7 of the of the total.
00:30:10.079 --> 00:30:15.599
In fire modeling, I believe the default would be 0.35, but you can correct me on that.
00:30:15.599 --> 00:30:25.119
It kind of stabilizes for large fires, it's it's slightly different for uh small fires, very small fires, which were where it would be important.
00:30:25.119 --> 00:30:37.839
So those would be the properties, the heat release rate, convective heat release rate, fire perimeter, in a way also the diameter of the fire, the location of the virtual origin, the triangle rule.
00:30:37.839 --> 00:30:43.759
Those will be the properties that you define when you model a fire with a simple plume model.
00:30:43.759 --> 00:30:55.759
If you go to zone model, well, it's kind of the same, because the zone models just assume there are two zones in the building, the hot gas layer and the cold uh underneath it.
00:30:55.759 --> 00:31:01.039
And the fire is usually defined by a plume model in the zone model.
00:31:01.039 --> 00:31:08.160
So the plume model is the engine that uh moves the gases from the lower region to upper region of your room.
00:31:08.160 --> 00:31:13.119
It's the engine that creates energy and the mass and it goes into all the equations.
00:31:13.119 --> 00:31:19.680
So if you know, if you're comfortable with plume models, uh you should also be comfortable with zone models.
00:31:19.680 --> 00:31:22.400
It's essentially the same math.
00:31:22.400 --> 00:31:36.880
Now, as much as I like zone models, and that was one of the first uh episodes I've ever recorded in the podcast with uh Colleen Wade about zone modeling not being dead yet, and I still believe zone modeling is not dead yet.
00:31:36.880 --> 00:31:43.680
The expectations of our peers, the expectations of other stakeholders of our clients is that we deliver CFD.
00:31:43.680 --> 00:31:47.119
So now let's move into how we define those in CFD.
00:31:47.119 --> 00:31:49.200
And is it more complex or not?
00:31:49.200 --> 00:31:51.119
That's a stupid way to put it.
00:31:51.119 --> 00:31:54.079
It's obviously more complex, that's what the clients are paying for, right?
00:31:54.079 --> 00:31:57.759
More complexity in the colorful pictures we sell them.
00:31:57.759 --> 00:31:58.079
Yeah.
00:31:58.079 --> 00:32:07.839
Jokes aside, uh, you're a good fire engineer, you spent 30 minutes with me learning about fire physics, so you you definitely want to do this well.
00:32:07.839 --> 00:32:11.680
Uh let's let's talk about how we do it and how to do it well.
00:32:11.680 --> 00:32:24.000
Uh we have multiple ways we can introduce fires into CFD models, and those ways are also kind of related to the type of software that you are using.
00:32:24.000 --> 00:32:33.279
Because if you are using FDS, you probably already are committed to a specific path of entering the fire into your domain, which is not the only path.
00:32:33.279 --> 00:32:38.240
There are there exist different pathways to introduce fires into CFD models.
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