I've finally done it. We've repeated Jin's experiment! I thought I knew-it-all about that experiment, but boy... knowing and doing it are two different things. I can say, I've finally cleared my mind on some thoughts after this, which I am finally happy to share with all of you!

First things first, massive thanks to my partner in crime Wai-Kit Wilson Cheung, from the group of prof. Xinyan Huang, who was the man on the ground doing the experiments with me. Together we went further into this model, than ever before. 

The revelations are far-reaching. We found that Jin used extraordinary lighting conditions—180 lux background brightness and impossibly bright signage—far from realistic building emergency conditions. Background brightness emerges as perhaps the most critical factor in determining what can be seen through smoke, with dramatic differences between light-emitting and light-reflecting signs. Most significantly, the experiment's careful constraint of sign size (using proportionally larger signs at greater distances) created elegant mathematics but removed a crucial real-world variable from the model.

These insights have profound implications. Engineers likely overestimate visibility in many scenarios, particularly with reflective signage. The widely used K-values (3 for reflective signs, 8 for light-emitting signs) appear reasonably conservative for typical building conditions, though higher values might be warranted in darker environments. Most provocatively, simply increasing sign size would almost certainly improve evacuation safety, yet our current models provide no mechanism to quantify this benefit.

Fire safety practitioners will find this episode transformative, offering both practical guidance and theoretical understanding. Should we stick with visibility distance or shift to smoke density as our primary metric? How can we balance lighting conditions to optimize visibility of both obstacles and signage? And most critically, how might next-generation visibility models better serve real-world building safety? These are things we currently work on.

If you look for reading, check the paper on the extinction coefficient by the German colleagues:  https://arxiv.org/abs/2306.16182

If you strive for more podcast episodes:

• this one covers historical Jin's experiment: https://www.firescienceshow.com/162-experiments-that-changed-fire-science-pt-9-jins-experiment-on-visibility-in-smoke/
• this one is on soot and smoke: https://www.firescienceshow.com/163-fire-fundamentals-pt-11-soot-in-fire-safety-engineering/
• and this one our general thoughts about modelling visibility and new pathways we see forward: https://www.firescienceshow.com/030-visibility-prediction-framework-with-lukas-arnold/

The research was funded by the National Science Centre, Poland, based on a contract for the implementation and financing of a research project OPUS LAP No 2020/39/I/ST8/03159 and by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under the project number 465392452, for the joint project: “Visibility Prediction Framework – a next-generation model for visibility in smoke in built environment”. 

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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.

The gap between fire safety engineering and firefighting operations creates a profound challenge that affects building safety worldwide. Even experienced fire safety engineers - myself included - face uncertainty when designing for firefighters without being firefighters themselves. Yet many building codes explicitly require engineers to account for firefighting operations in their designs.

This examination dives into the timeline analysis essential for effective firefighter support, from notification (when firefighters learn about the fire) to arrival at the building to actual intervention. Each phase contains complexities often overlooked: fire alarm systems might be delayed by human verification, architectural complexity can significantly slow down firefighters reaching the fire, and building conditions upon arrival dramatically affect intervention capabilities.

The assessment of design fires represents one of the most challenging aspects of this engineering work. At what fire size will firefighters begin their intervention? The fire might be growing, steady-state, limited by compartmentation, or controlled by active systems. This crucial but uncertain consideration fundamentally shapes how we design for firefighter safety.

Through computational fluid dynamics modelling, we can evaluate the building conditions firefighters will face. Rather than using simple pass/fail criteria, experienced engineers look for smoke layer behaviour and clear access paths. The gold standard is providing smoke-free routes from the building entry to the fire vicinity. When this isn't possible, we must carefully evaluate the conditions through which firefighters must navigate.

Fire safety systems - from sprinklers to smoke control, information displays to architectural layouts - all dramatically influence firefighter effectiveness. Yet perhaps the most important principle is creating systems firefighters trust. Overly complex designs may be disabled by firefighters who don't understand them or don't trust them with their lives.

The most effective approach combines rigorous engineering analysis with direct input from firefighters themselves. By understanding their actual needs, which might surprise you - we can design buildings that truly support those willing to risk everything to save others. What would your building design look like if you asked firefighters what they really need?

Listen to the entire episode with Szymon Kokot here: https://www.firescienceshow.com/051-fire-science-in-eyes-of-a-firefighter-with-szymon-kokot/

Want to know what happens in the building after a fire alarm? Find out here: https://www.firescienceshow.com/136-fire-fundamentals-pt-6-the-fire-automation-in-a-building/

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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.

What happens when a lifetime of studying industrial fire hazards meets the creative mind of a novelist? In this conversation with Professor Joaquim Casal, we explore the unique intersection of fire safety engineering and science fiction through his novel "The Last Fire."

Professor Casal, a retired academic from Universitat Politécnica Catalunya and founder of their fire research group, has crafted something unique – a  novel where the protagonists are fire researchers and the plot revolves around fire phenomena, fire research and fire testing. 

Beyond the novel on its own, our discussion also takes us deep into the world of industrial fire hazards, exploring phenomena that many building-focused fire engineers rarely encounter. From the extreme temperatures of jet fires that can trigger catastrophic "domino effects" in industrial facilities to the deadly "boil-over" phenomenon that has claimed numerous firefighters' lives. We examine the behaviours of jet-fires, pool fires, flash fires, and the spectacular but devastating fireballs created by BLEVEs (Boiling Liquid Expanding Vapor Explosions).

And finally, I think the greatest imminent value of this novel is in the communication - it is a brilliant example of how you can communicate difficult technical concepts of fire to lay people. I believe many fire engineers could be inspired by this example.

If you would like to read the novel, it is available at Amazon:

https://www.amazon.co.uk/Last-Fire-Joaquim-Casal-ebook/dp/B0F4QYLYSV

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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.

Episode 200! And for this special episode,  I've travelled to London to interview Prof. Guillermo Rein and Dr Matt Bonner on a piece of research carried out at Imperial College London, with the experiments performed in our laboratory at the ITB.

In this episode, we discuss the concept of flammability of the building facades and how this flammability is assessed with different testing methods available in the world. You could argue that every country has their own method, and in some cases, they use those methods even with varying criteria of acceptance. Even though the methods are as different as they can be, they all claim they test for fire safety of the external façade and are used as the basis for local regulatory regimes. Knowing that so many methods exist, we approached this with a question: Will they agree on ranking different facades? Will they show us the same results, or will each show us something else? And this question is inspired by Prof. Howard Emmons, who in 1968 went into a similar endeavour with building materials. Back then, Emmons said:

“Such profound disagreement between serious attempts to measure combustibility points out better than any argument that we really don’t know what we are talking about when we say, ‘this is more combustible than that’; ‘this is a more safe building material than that’”.

In this podcast episode, we discuss a series of 25 experiments: testing five facades, two ETICS and three rainscreen facades with a varying degree of use of combustible materials. All the material combinations were built by us in the same way, and then assessed using five test standards: 

• The Polish method PN-B-02867, 
• The international screening method ISO 13785-1 (smaller corner configuration), 
• The German method DIN 4102-20, 
• The American method NFPA 285, also used globally
• and the British BS 8414, also highly influential over the world and the basis for the new harmonised EU approach.

We go into the background and rationale of the experiments, an overview of the testing methods as well as into qualitative and quantitative findings of the study.

Once the paper is published, I will update the shownotes with a link here :)

For now, you may also want to revisit previous episodes of Fire Science Show discussing the fire safety of facades – 

• It all started with episode 4 with Matt Bonner: https://www.firescienceshow.com/004-facade-fires-and-ai-with-matt-bonner/
• An overview of current Issues with Eleni Asimakopoulou: https://www.firescienceshow.com/124-advancements-in-fire-safety-of-facades-with-eleni-asimakopoulou/
• And some interesting facts about SBI method with Rudolf van Mierlo (and their development of façade testing method): https://www.firescienceshow.com/140-development-and-implementation-of-the-sbi-test-with-rudolf-van-mierlo/

This research was funded by The Berkeley Group. The experimental part was performed at the Building Research Institute ITB, with a group of tests with the Polish method performed as part of our statutory research NZP-130.

Thank you for being with the Fire Science Show for 200 episodes! Huge shoutout to the OFR for enabling this project and allowing me to share insights like this with all of you in an open-access repository!!!

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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.

We know a whole lot more about mass timber in fire than we did a few years ago (even when I’ve just started the podcast 199 episodes back …). But is this knowledge widely used in engineering practice? Is it used in the same way by different stakeholders? Definitely not.

This is why to move timber into something we would consider “new normal”, we need more than research. We need a consensus on how to apply the outcomes of our research in practice. And this is this podcast episode.

Built by Nature, with a group of investors, property owners, and managers, funded a grant led by Elliot Wood to write a “consensus” guideline on using mass timber in office buildings. A large part of the book covers fire, which we also cover in this podcast episode. 

I’ve invited prof Danny Hopkin and Luis Gonzalez Avila from OFR to walk me through the story of the guidebook, its contents of it and we also jump deep into the design philosophy of the book.

https://builtbn.org/knowledge/resources/commercial-timber-guidebook/

In this podcast episode, we try to stay away from explaining how timber burns (sorry!). But if you want to know more about physics, the Fire Science Show has you covered. Check out the timber section of the podcast! Look here: https://www.firescienceshow.com/categories/timber/

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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.

The devastating impact of waste and recycling industry fires costs approximately $2.5 billion annually in the US and Canada alone, with lithium-ion batteries causing roughly 50% of these incidents. In this episode with Ryan Fogelman from Fire Rover, we discuss:

• Understanding the scale of waste facility fires and why traditional fire protection methods often fail in these environments
• How lithium-ion batteries have created a "hockey stick" rise in fire incidents since 2015
• The "vape effect" - how 1.2 billion single-use vapes with no proper disposal options are contributing to the fire crisis
• Why remote monitoring and response systems can detect and fight fires faster than traditional sprinkler systems
• The importance of early intervention - FireRover's systems respond in seconds rather than minutes, and targeted suppression uses 88% less water than traditional methods while providing more effective control, reducing the contaminated water spill
• Why waste and recycling operators are victims of consumer disposal habits and regulatory gaps
• The need for more convenient battery drop-off locations to prevent improper disposal
• How innovative fire solutions are changing the approach from "water, water, water" to targeted remote response

Visit firerover.com to learn more about remote fire suppression solutions for waste facilities or contact Ryan Fogelman on lnkd for a free PDF copy of the latest "Waste & Recycling Facility Fire Annual Report"

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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.

When wildfire threatens neighbourhoods with closely-spaced homes, what determines whether flames leap from one structure to the next? The FSRI research team - Rebekah Schrader, Joseph Willi, Daniel Gorham and Gavin Horn - joins us to unveil their experimental series that methodically dissects the pathways through which fire spreads between buildings.

The team walks us through their massive outdoor experimental setup, where they created controlled compartment fires and measured their impact on adjacent walls and windows at various separation distances. They discovered that even non-combustible exterior cladding like fiber cement board won't necessarily protect a home when the underlying sheathing is combustible—especially at close distances where heat fluxes reach a staggering 75-125 kW/m².

Windows emerge as perhaps the most vulnerable component, with their research revealing dramatic differences in performance between glass types. Double-pane tempered glass significantly outperforms plain glass configurations, but the surprising finding was how much window frame materials matter. In one experiment, vinyl frames completely failed while the glass was still intact, causing entire window assemblies to drop from the wall.

Another aspect of their research are the measurements of the heat transfer through intact windows. Using specialized measurements, they found that significant radiant heat penetrates even unbroken windows, potentially igniting curtains or furniture inside before the window itself fails. Low-emissivity coatings proved remarkably effective at reducing this heat transfer.

This research offers crucial insights for homeowners, fire safety engineers, and policymakers working to create more resilient communities. The findings extend beyond wildland fire applications, providing valuable data for urban fire safety engineering across multiple contexts.

Find the research papers at:

• https://onlinelibrary.wiley.com/doi/10.1002/fam.3278
• https://link.springer.com/article/10.1007/s10694-024-01685-8
• https://link.springer.com/article/10.1007/s10694-024-01656-z

And additional resources at:

• https://fsri.org/research-update/journal-article-reports-heat-transfer-through-different-window-constructions
• https://fsri.org/research-update/journal-article-investigates-role-residential-siding-materials-spread-exterior

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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 this podcast episode, we host Rebekah Schrader, Joseph Willi, Daniel Gorham and Gavin Horn, all from the FSRI, to cover their recent experimental research on fire spread through external walls. This is part 1 of the interview - the background, rationale and context. In part 2, we cover the experiments themselves, findings and actionable guidance from the experiments.

This research is conducted within the context of structure-to-structure fire spread, potentially in urban conflagration scenarios. The subject is most relevant, as when wildfires meet urban areas, they transform into something far more destructive – "wildfire-initiated urban conflagrations." These events devastate entire communities as fire spreads rapidly from structure to structure, overwhelming firefighting resources and leaving widespread destruction in their wake.

The Fire Safety Research Institute has embarked on a comprehensive research initiative examining exactly how these conflagrations develop and spread. What started as a response to their advisory board's call to action in 2018 has evolved into a groundbreaking exploration of the complex interactions between wildland fires and the built environment.

We break down the three primary mechanisms of fire spread – radiant heat, direct flame contact, and firebrands – while highlighting specific vulnerabilities in modern construction, particularly windows and cladding systems.

What makes this research particularly valuable is how it bridges traditionally separate disciplines: wildfire science and structural fire engineering. The team explains how they've translated complex wildfire scenarios into controlled laboratory experiments that yield actionable data for improving building codes and community design.

Whether you're a fire safety professional, community planner, or homeowner in a wildfire-prone region, this conversation offers crucial insights into how we can create more resilient communities in the face of this growing threat.

In the next episode, we will cover in depth the details of three experiments mentioned today.

Find the research papers at:

• https://onlinelibrary.wiley.com/doi/10.1002/fam.3278
• https://link.springer.com/article/10.1007/s10694-024-01685-8
• https://link.springer.com/article/10.1007/s10694-024-01656-z

And additional resources at:

• https://fsri.org/research-update/journal-article-reports-heat-transfer-through-different-window-constructions
• https://fsri.org/research-update/journal-article-investigates-role-residential-siding-materials-spread-exterior

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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.

The UK's Building Safety Act requires high-risk buildings to maintain comprehensive fire safety cases - living documents that identify hazards, mitigate risks, and establish clear accountability for building safety. This is the subject of my discussion with Chris Mayfield and Martyn Ramsden from OFR.

• Safety cases differ from fire strategies by being owned by the building's accountable person rather than consultants
• The Principal Accountable Person must take responsibility for preventing fire spread and structural failure
• Safety cases must document hazards, protective measures, and management systems
• The approach draws from lessons in high-hazard industries following disasters like Piper Alpha
• Safety cases should follow a logical structure: building description, safety management, hazard identification, safety measures, emergency procedures, and conclusions
• Bow tie diagrams help visualise threats, consequences, and barriers in a way all stakeholders can understand
• For new buildings, safety cases integrate with the "gateway" approval system
• Existing high-risk buildings (over 18m/7 stories with 2+ dwellings) must have safety cases ready for inspection
• When properly implemented, safety cases create cultural change by helping everyone understand their role in safety

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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.

Professor Xinyan Huang from Hong Kong Polytechnic University shares his expertise on battery fires and the various experimental methods researchers use to trigger thermal runaway events under controlled conditions.

• Terminology matters - "thermal runaway" more accurately describes battery failure than "ignition" as the critical reactions occur inside the cell
• Nail penetration testing is widely used but contains surprising complexities, including nail material, penetration depth, velocity and battery orientation
• Mechanical abuse tests (crushing, dropping, squeezing) simulate real-world accidents but often lack repeatability
• Thermal abuse via heating typically targets 200°C surface temperature using methods including flame exposure, electrical coils, and laser heating
• Electrical abuse through overcharging (150-200% SOC) significantly increases risk, while poor-quality charging equipment creates additional hazards
• State of charge plays a crucial role in how batteries respond to abuse tests
• New research aims to bridge the gap between micro-scale material testing and cell-level testing

Professor Huang is organising the 4th International Symposium on Lithium Battery Fire Safety (ISLBFS 2025) in Hong Kong from October 30th to November 2nd - the largest battery fire safety conference in the world.

I intended to link Xinyan's papers on batteries, but there is 19 of them!?! Let me link the most recent ones:

• Dynamic thermal runaway evolution of Li-ion battery during nail penetration
• Modeling liquid immersion-cooling battery thermal management system and optimization via machine learning
• Laser-induced thermal runaway dynamics of cylindrical lithium-ion battery
• Effect of thermal impact on the onset and propagation of thermal runaway over cylindrical Li-ion batteries
• A Review of Battery Fires in Electric Vehicles
• Alleviation on battery thermal runaway propagation: Effects of oxygen level and dilution gas

Cover image source: https://doi.org/10.1016/j.est.2024.111337

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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.