Fire Science Show

If you ever had anything to do with Fire Safety Engineering, you have most likely touched the visibility in smoke. What's an easier way to explain how bad the conditions are inside of a building than saying how much smoke was there? And what's a better way to define smoke than saying how far can you see? It's brilliant. We have agreed (unwillingly, somewhere in the '60s) that if visibility is kept at a good'ish level of 10 m or more, conditions inside are fine.  And we know how to calculate it, so it seems we're in a great place.

Well. Not really. Our models for this are quite bad. And there is no one reason for that - from physics, through the assumptions, commonly used constants (magical numbers if you prefer that name) to implementation of this approach into CFD, which was never foreseen by its creators. Together with prof Lukas Arnold we have figured out that this requires not only an improvement but preferably - a complete revamp. After that, we have written a grant application, and guess what - WE GOT IT!!!

In this episode, you will learn everything about the faults of the visibility in the smoke model and how we intend to change it. Please join us in this discussion, and if you have some great ideas on how to make our work better, please be sure to tell us! We are listening and looking forward to changing the FSE together, forever.

As we are just starting, please feel welcome to check existing resources by our teams on the visibility in smoke:

• Fire Science Show Episode 3 with Gabriele Vigne - there is this crazy fire podcast that covers so much!
•  My presentation at UK Fire and Smoke Modelling Forum on YouTube with a lot of background on how the model works (or rather, why it does not work)
• Robust value of Soot Yield for complex materials found at 0.1 with Gabriele Vigne
• Multi-wavelength sensitivity of the smoke obscuration models by W. Wegrzynski et al.
• How to measure visibility in a small scale? by W. Wegrzynski et al.
• A map representation of ASET-RSET by B. Schroeder et al.
• Spatiotemporal measurement of light extinction coefficients in compartment fires by L. Arnold et. al

This research was funded in part by National Science Centre, Poland in the grant OPUS 2020/39/I/ST8/03159.

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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.

This is not a fun episode. It starts with a tragedy, that fueled a whole field of research. Continues into disbelief, that one aspect of fire safety can be at the same chosen as the sole foundation of fire safety within a branch of engineering, and at the same time at a pretty low, clearly insufficient level... And then comes the true shocker - solutions exist and we just don't use them. Because of, who knows why. An unknown force...

Ok, I have spoiled you a bit, but it is absolutely worth hearing the full story that my guest, dr Anja Hofmann-Böllinghaus has to deliver. It is a journey through the world of the resistance to fire and at the same time the frustration and challenges that fire engineers have to go through. And above everything, it is a call for making busses and other means of mass transport safer, by employing the knowledge and solutions we already have!

If you liked it, please take a minute to connect with Anja on her Twitter and LinkedIn 

If you would like to learn more about the fire safety of means of transport, please check out these items:

• Anja Hofmann, Steffen Dülsen, Michael Försth, Jonas Brandt. What can we learn from European train fire safety regulations for fire safety regulations for busses? FIVE 2018, October 2dn – 3rd 2019, Boras, Sweden - in proceedings of FIVE 2018
• Krueger, Simone; Hofmann, Anja; Berger, Anka; et al. Investigation of smoke gases and temperatures during car fire - large-scale and small-scale tests and numerical investigations
• Anja Hofmann, Steffen Dülsen, Georg Scholzen. Rapid fire spread in a bus depot fire. FIVE (Fire in vehicles) Conference 2014, October, 1-2, 2014 in Berlin - in proceedings of FIVE 2014
• A. Hofmann, S. Dülsen, A. Klippel. Problems in bus fire safety – recent developments and possible solutions. Fire and Materials Conference, 28.-30.1.2013, San Francisco, USA

Also, please check the website of the Fires In VEchicles (FIVE) conferences, which is possibly the best place to learn about the issues and solutions within this sector  - https://www.ri.se/en/five

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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.

Have you ever been fascinated by the capabilities of AI? Did you wonder how the heck can an algorithm beat humans in repetitive tasks? Or make multi-level correlations that we would never be able to figure out? I was as well. And I felt the urge to learn more about this technology, in a way to not be left out when everyone plays with their new toys... But at the same time, I felt this feeling of overwhelm and confusion about this technology. What exactly is it, where to start... Then the wall of multiple choices to take - am I even trying supervised or unsupervised learning? Is my problem a regression or classification? I won't lie, it's hard already, and I have not even really started yet.

And then comes him. Dressed in white (just kidding). MZ Naser.

MZ is not only a genius who seems to have figured it out in the world of fire, but he is also documenting every step of his path in research papers. More to that, he also wrote a bunch of entry-level papers, and a review paper summarizing the basics and explaining the core concepts. Wow, what a service to the community! Please join me in this discussion in MZ, where he literally walks me through the fascinating world of AI in fire and explains where to start.

At this point of the show notes, I would list you a bunch of papers and relevant resources.
(Update: originally  there  was  just link to MZ’s site, but as this got published you totally need to start with this paper:  https://www.readcube.com/articles/10.1007/s10694-021-01210-1 )

 MZ Naser is so nice, he has a website where all of this is summarized and kept updated! If I started listing the resources, I would do you a disservice... You have to test what he has out there.

https://www.mznaser.com/

And also, please connect with MZ at his Twitter and LinkedIn 

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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.

If you have ever learned about the compartment fire dynamics framework, have tried zone modelling or any kind of fire modelling, you have probably noticed that as the compartments get bigger, the less uniform conditions inside are. At some size, the flashover or a "single-zone" model theories just break, MQH equation does not give a reasonable solution and the fire seems not capable of growing to a huge size... But yet, they destroy buildings. Local fire exposure may be damaging to structural elements in the same way as a flashover is. And that is how we considered it for many years...

But there was a gap. Something between a localized fire and a flashover'd fire. For many years we've seen it, but we have not acknowledged it fully untill it was given a name - the Travelling Fire. In today's episode, I have invited prof. Guillermo Rein of Imperial College London, to tell us the origin story, recent developments and future plans related to this methodology. This should be interesting to all - from fire scientists to engineers.  IMHO, a well invested hour of your time!

Make sure to connect with Guillermo on socials:
- Twitter
- LinkedIn
and with his group - Imperial Hazelab (also on Twitter).

Guillermo has published 200 research papers, and among them many landmark pieces on travelling fires that I recommend:

• Travelling fires for structural design (2012) with J. Stern-Gottfried
• Improved formulation of Travelling Fires (2015) with E. Rackauskaite et al.
• Improved Travelling Fire Methodology - iTFM (2017) with E. Rackauskaite
• Computational analysis of thermal and structural failure criteria of a multi-storey steel frame exposed to fire (2019) with E. Rackauskaite et al.
• Flame extension and the near field under the ceiling for travelling fires inside large compartments (2020) with M. Heidari et al. 
• Fire Experiment Inside a Very Large and Open-Plan Compartment: x-ONE (2021) with E. Rackauskaite et al. 
• Thermal Response of Timber Slabs Exposed to Travelling Fires and Traditional Design Fires (2021) with F. Richter et al.

and some many more... You may also be interested in the relevant PhD thesis:
- Jamie Stern-Gottfried (2011)
- Egle Rackauskaite (2017)

And some other work related to travelling fires carried across the world:

• RK Janardhan and S Hostikka When the fire is spreading and when it travels? 
• X Dai et. al. Extended Travelling Fire Methodology
• D Hopkin Testing the single zone structural fire design hypothesis
• C Maluk Energy distribution analysis in full-scale open floor plan enclosure fires

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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.

Thanks to the courtesy of the International Water Mist Association I have been invited to the recent conference held in Warsaw. The conference was a two-day event focused on water mist technology. In fact, it was the 20th meeting of this kind, and in a way special, as it was the first at which the new European standard EN 14972-1, which is a cornerstone for the future growth of this technology. You can learn more about the standard here.

It was a huge pleasure to participate in the conference, and I must say I have learnt a lot about water mist technology. Out of all talks, the one I have enjoyed the most was probably the talk by Arnstein Fedøy on sprinkler reliability. You will hear more about this in the podcast episode and you can also check Arnstein's book on sprinkler reliability. For me, the runner up was Max Lakkonen who discussed the use of numerical modelling in the water mist world, but I admit, I am biased. The CFD is my world and I love hearing a different perspective from a different industry. It was refreshing to hear Max's balanced stance on what can and what cannot be done. I regret not interviewing him, but at least I have discussed the matter with Alex Palle - one of the leaders of the water mist industry from VID Fire Kill. Alex told me what's all the fuzz with the EN standard, and why it is such an important step for the community.

I wish I could cover every talk that was given, as their technical level was really good, and I have enjoyed all of them. Hopefully, some of these resources will be made publically available, and if not, keep your eyes open for the next IWMA conference in 2022 (I've heard it will be in Madrid).

In the meantime, if you would like to learn more about water mist technology, the IWMA website is full of great resources, which I highly recommend exploring. Starting with How does the watermist work? by Bettina McDowell and other seminar papers shared on the site. You should also check their position papers on the water mist technology.

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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.

In Episode 18  we have touched on the important topic of fire performance of engineered wood and its wide use in the modern built environment. Today,  we follow up on this subject with Dr Felix Wiesner from the University of Queensland. We leave the (important) topic of compartment fire dynamics and focus on what happens inside the wood in the fire. And there is much more going on than I have initially thought... The transport of moisture, weakening bonds at the glue line and connections, complex thermodynamics of char layers... I will be honest - this is not an easy episode. But that is how it is supposed to be. Because this topic is not easy. You cannot proxy all of these considerations with simple fire resistance. You cannot pretend these issues do not exist.

So the next time someone writes on LinkedIn that "wood in fire is stronger than steel" please send them a link to this episode, with a comment that it is not that simple...

You should definitely follow Felix on Twitter, where you can learn a lot about timber in fire and be updated with the progress on the National Centre for Timber Durability and Design Life.

To arm you up with some resources, please check Felixs' PhD Thesis on "Structural behaviour of cross-laminated timber elements in fires".

In terms of papers interesting ones to read on the structural reductions in the cooling phase are: 

• Wiesner et al, Structural capacity in fire of laminated timber elements in compartments with exposed timber surfaces – for a theoretical consideration of the problem based on real temperatures. The predictions of capacity loss for the glulam column are from tests that were done for a real building.
•  Wiesner et al, Structural Capacity of One-Way Spanning Large-Scale Cross-Laminated Timber Slabs in Standard and Natural Fires where they've validated the model from the paper above in follow up tests by CERIB
• And they have also checked the recovery potential of heated stiffness loss in the following paper (which originated from my PhD). There was no recovery! There was a big dependency on the adhesive type and ply thickness in the loss in structural capacity, which was kind of the whole theme of the PhD - Wiesner, Deeny, and Bisby, Influence of ply configuration and adhesive type on cross-laminated timber in flexure at elevated temperatures

 In terms of testing of structural wall elements, there is the following paper, which kind of then kickstarted a lot of Felixs' PhD research. He says "I was very fortunate to have worked with great Masters students on this and other projects" Wiesner, Randmael, Wang, Bisby, and Hadden Structural response of cross-laminated timber compression elements exposed to fire)

 Also, if your listeners are interested in outcomes from sitting hours in front of a Universal Test machine and waiting for the wood to heat up to specified temperatures before crushing it then they might be interested in the following paper:  (Wiesner, Thomson and Bisby, The effect of adhesive type and ply number on the compressive strength retention of CLT at elevated temperatures). Again we found that adhesive is an important factor in determining failure temperatures in CLT. Also a big difference between transient and steady-state heating.

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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.

Who is a Fire Safety Engineer? And when do you become one? How do you know the person on the other side of the table at the project meeting has the necessary competencies to judge fire safety solutions of a building you design?

That is a problem with (a) the definition of the profession and (b) the definition of the core competencies related to the profession. And both of these issues are close to the heart of my guest, Jimmy Jönsson, Director at JVVA in Spain and a member of SFPE Board of Directors. Jimmy has led an SFPE "Core Competencies" task group which created a reference document - Recommended Minimum Technical Core Competencies for the Practice of Fire Protection Engineering. 

In our talk, we dive deep into the competencies of fire engineers, and to what particular tasks these competencies are required. You will learn where one can obtain the broad view over a fire science, and why Jimmy would rather hire someone with wide but shallow knowledge, over a specialist without a fire engineering background.

If you are looking for more resources, SFPE has some goodies for you:

• almost every good FPE university has now an SFPE Student Chapter, and you can find the list of all of such chapters here
• Pathways to a career in FPE
• Higher education in FPE

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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.

Risk as a concept is well established in modern Performance-Based Design in Fire Safety Engineering. However, it comes in many flavours - from a simple calculation of consequences vs probability, through indexing methods and using some arbitrary measures (number of fatalities, cost of damage etc.). Most of these methods focus on the value or threshold of the risk... while my today's guests seem to focus much more on the process itself.

Today I'm happy to host Dr Jaime Cadena Gomez (UQ, Transurban) and Dr David Lange from UQ, who will introduce us to the Maximum Allowable Damage risk assessment methodology. Two unique things about this approach are:
1) you calculate the inherent risk of your building, and start working towards solutions from this point, making the whole engineering process better aligned with delivery of a *true* safety, rather than compliance.
2) you focus on the process and not on the measure. This means you understand the building so much better, can include other parties and authorities in the process.

If you are a Fire Safety Engineer you should listen to this episode. Even if the method will not be useful for you, the discussion is definitely refreshing.

Connect to my guests:
Jaime Cadena on Linkedin
David Lange on Linkedin

A short introduction to Jaime's work:
https://www.youtube.com/watch?v=_6YOBkS9Uds

Read more on the Maximum Allowable Damage methodology at:

•  Jaime's PhD thesis
• Cadena et al. Overcoming risk assessment limitations for potential fires in a multi-occupancy building
• Cadena et al. Uncertainty-based decision-making in fire safety: Analyzing the alternatives

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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.

https://firelab.berkeley.edu/ this is the place you need to go!

Ignition at different slope angles. Firebrand spotting. Fire whirls. What does connect these various fire phenomena? They are all driven by fluid dynamics and can happen only in very particular flow conditions. To define and understand these conditions... well that is a bit longer story that I will unravel with Prof. Michael J. Gollner of the University of California, Berkeley.

In Episode 14 we have gone on a journey through scales of the fire phenomena with Sara McAllister (USDA).  Today's episode is in a way follow up to that journey, as with Michael we try to understand why slope angle is such an important variable in the ignition of solids (and why peakHRR is not necessarily at the same slope as peak fire spread!).  We venture into wind-driven crown fires and ember generation within them. Finally, we discuss the fire whirls, and notably - Michaels team discovery of "blue fire whirl" during his time in UMD. Although the topics seem very fundamental, we stay in touch with engineering... In the end, the influence of slope angle on the flame spread is interesting, and at the same time fundamental to predicting wildfire spread. Firebrand aerodynamics is fascinating, but if we don't understand that, we won't be able to build homes resilient to wildfires. Blue whirl is beautiful, but one day it may be the answer to efficient cleaning of oil spills. This episode is full of fantastic fire science, for everyone!

Connect with Michael on Twitter and LinkedIn

Check the collection of resources for fire protection engineers on Firelab Berkeley website.

Read up on Michaels research:

• Studies on upward flame spread (PhD Thesis at UCSD)
• M Finney et. al. Role of buoyant flame dynamics in wildfire spread PNAS
• A Tohidi, MJ Gollner, H Xiao, Flame Whirls Annual Review of Fluid Mechanics
• H Xiao, MJ Gollner, ES Oran, From fire whirls to blue whirls and combustion with reduced pollution PNAS

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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.

It is hard for us, fire safety engineers, to talk to firefighters on how to do their job... Probably we even shouldn't, as we have no idea how it is to truly go there into the heat and battle fire to save lives. But it does not mean we should not care. Firefighters are important actors in the fire safe world, and we cannot design buildings as if they were not. In the end, the probability of you being in a fire is fairly low, while for a firefighter this P = 1. Our decisions shape the building environment, which acts as a battleground for them, affects their actions and options. And we can design buildings better!

My today's guest, dr Ali Ashrafi of Thornton Tomasetti is passionate about building safer buildings. Ali highlights the key elements of making the building safer for firefighters, with a great focus on the structural resilience of the buildings. Highlighting the performance-based design approach he claims that we can build not only better but also cheaper at the same time. Well, that's kind of a win-win situation... If you want to learn more, this episode is for you.

Learn more about Ali at:
https://www.thorntontomasetti.com/person/ali-ashrafi

And connect with him through LinkedIn

Followup material:

• A presentation about Performance-Based Design of Buildings in Fire: Implications for Firefighting
• Performance-based structural fire design: Exemplar Design guide developed by ASCE and Charles Pankow Foundation
• Dan Madrzykowski Using Fire Dynamics Research to Save Firefighters
• Stephen Kerber, Dan Madrzykowski Fire Behavior and Tactical Considerations
• NIST & UL Research on Fire Behavior & Fireground Tactics

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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.