In this episode we try to demonstrate another step in integrating fire engineering into WUI risk management, and vice versa. These two areas together form some sort of fire engineering method, which I strongly believe will be an important part of our profession in the future. Today I got to sit down with Dr. Pascale Vacca from UPC to unpack a practical, end-to-end framework for wildland–urban interface risk that engineers can use today, which she has shared in her keynote at the ESFSS Conference in Ljubljana earlier this year.

From mapping hazard, exposure, and vulnerability across scales to chaining wildfire spread outputs into building-focused simulations, we show how careful modeling turns uncertainty into a plan communities can fund and maintain.

We begin with risk assessment that respects terrain, fuels, and construction typologies, then translate FARSITE’s rate of spread and fireline intensity into FDS boundary conditions to test real weaknesses—like heat flux and breakage in large glazed facades. The case study in Barcelona grounds it all: what happens when wind pushes a fast front toward a community center, and which retrofits move the needle? Noncombustible shutters, smarter venting, and defensible spacing emerge as high-ROI fixes, while fuel breaks and fuel treatments reduce intensity so crews can act. Along the way, we tackle data resolution, moisture, and weather selection—how to choose between worst case and representative scenarios and why that choice matters for policy and budgets.

Preparedness and recovery complete the cycle. Annual maintenance keeps gains from eroding as vegetation regrows; community preparedness days build habits and trust; and a homeowner app scores parcel risk to make decisions concrete. On the response side, precomputed scenarios and quick wildfire modeling inform shelter-in-place versus evacuation, aligning engineering insight with operational realities. We also confront limits: validation gaps, ember exposure, and the fact that risk is never zero. But the path forward is clear—interdisciplinary planning, better data sharing after fires, and education to bring more engineers into WUI work.

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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.

Fire doesn’t play by Earth’s rules once you leave gravity behind. In this deep dive with Professor Michael Gollner, we unpack what the recent experiments at the ISS called SoFIE-MIST taught us about solid fuel flammability in microgravity—how tiny ventilation, oxygen levels, and pressure shifts determine whether a flame spreads, stalls, or vanishes. The details are surprising: blue “bubble” flames, two distinct extinction points, and sustained burning at oxygen levels that would fail to ignite on Earth.

We walk through the entire setup: PMMA rods chosen for clean, uniform burning; a compact wind tunnel inside the ISS hardware; ceramic heaters delivering 1–3 kW/m² to probe incipient behavior; and a control strategy that often lets the flame’s own oxygen consumption carry the chamber gently to extinction. Along the way, you’ll hear how constraints drive design—why rods beat flats, why halogen lamps didn’t fly, how crew time is minimized with robotic runs—and how data is captured without weighing anything. Opposed-flow flame spread becomes a window into fundamentals: radiative preheating, thermal thickness, and the delicate balance between convective loss and feedback when buoyancy is gone.

The implications stretch to future habitats and vehicles. As spaceflight moves toward longer missions and more commercial operators, safety will hinge on accurate flammability limits under low ventilation and non-Earth atmospheres. We connect the dots to normoxic choices, partial‑g research on the Moon and Mars, and the growing need for space fire engineering that’s grounded in real data. If you care about spacecraft safety, materials selection, and the science behind early fire detection, this conversation is right for you.

If you want to learn more, do it here:

• a brilliant article at the Berkeley website
• NASA Glenn website about the SoFIE programme
• Episode 75 with David Urban on spacecraft fire safety
• QA session 5 - brainstorming martian habitat fire safety

Cover image credit: NASA, Igniting a 12.7 mm sample at 21% oxygen under 100 kPa ambient pressure in microgravity. From article https://engineering.berkeley.edu/news/2024/12/nasa-funded-project-offers-new-insights-into-fire-behavior-in-space/

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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 episode we dive into the ap between standardized tests and experiments, trying to figure out (a) is there a difference and (b) if there is, could not understanding the difference quietly erode safety. With guest David Morrisset (Queensland University), we unpack furnace ratings that read like time but aren’t, cladding classifications that were never meant for façades, and the infamous bird-strike test that shows how any standard bakes in choices and consequences. The throughline: context rules everything.

We talk plainly about what tests actually deliver—repeatability, reproducibility, and comparability under fixed boundary conditions—and why that’s powerful but limited. Then we pivot to experiments: how to define a clear question, choose boundary conditions that matter, use standard apparatus for non-standard insights, and document deviations without pretending they’re compliant. We share stories from timber in furnaces to car park fires and design curves, showing when consistency beats a shaky chase for “realistic,” and when exploratory burns are the fastest way to find the unknowns that really drive risk.

If you’ve ever tried to drop a cone calorimeter value into a performance model, equated furnace minutes to evacuation time, or treated a single burn as gospel, this conversation will help you do this safely and prevent you from falling into some well known caveats. You’ll leave with practical heuristics for reading test data without overreach, structuring experiments that answer narrow questions well, and communicating uncertainty so decision-makers understand what the numbers can and cannot promise.

Essential reading after this episode:

• When chick hits the fan paper
• The rise of Euroclass, A. Law et al.
• The rise and rise of fire resistance, A. Law et al.

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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 episode, we give focus to the SFPE Foundation – a catalyst transforming how fire engineering research is funded, conducted, and shared globally. In this conversation with Leslie Marshall, Interim Executive Director of the SFPE Foundation, we discover how a relatively small organization has distributed over $1.2 million in grants, scholarships, and research funding since 2021. While the Foundation has existed since 1979, its recent expansion with dedicated staff has accelerated its impact across the fire engineering community worldwide.

Leslie reveals the Foundation's unique position in the fire safety ecosystem – while SFPE maintains the gold standard for current practice, the Foundation focuses on emerging topics and future challenges. This forward-looking approach has funded groundbreaking work, such as, in my opinion, landmark David Morissette's research on furniture fire variability, which began with a modest $5,000 student grant but yielded findings that challenge fundamental assumptions in fire modeling.

The conversation explores the Foundation's flagship Grand Challenges Initiative, a 10-year collaborative effort addressing four critical areas: energy and infrastructure, resilience and sustainability, climate change, and digitalization/AI/cybersecurity. With over 40 industry and academic partners worldwide, this initiative exemplifies how bringing diverse perspectives together can tackle complex problems that no single entity could solve alone.

For researchers, students, and professionals looking to give back to the fire safety community, Leslie outlines multiple pathways for involvement – from financial contributions to volunteering on advisory panels or working groups. The Foundation's commitment to open access ensures all research findings are freely available, maximizing their impact across the field.

You can learn more about the foundation on its website here.

Additional resources can be found here:

• The 2026 WUI Summit: https://www.sfpe.org/2026wuisummit/home
• The WUI Handbook: https://www.sfpe.org/wuihandbook/home
• Grand Challenges Initiative website: https://www.sfpe.org/gci/home

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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 the flames die down? It's a question rarely addressed in fire engineering, yet the decay and cooling phases of fires can be more dangerous than peak fire conditions. In this deep-dive conversation with Dr. Andrea Lucherini from Frisbee at ZAG in Slovenia, we uncover why these overlooked phases matter profoundly for structural safety.

Most engineers focus on protecting structures during the fully developed fire phase, but as Dr. Lucherini reveals, catastrophic failures can actually occur during cooling. We discuss a tragic case where seven firefighters died when a concrete structure collapsed, not during the fire's peak, but while they were extinguishing what appeared to be a dying fire. This sobering reality highlights how current testing methods fail to capture real-world risks—standard fire curves never decrease, creating a dangerous blind spot in our understanding.

The physics of cooling creates unique challenges for different building materials. Reinforced concrete might reach maximum temperatures in the steel reinforcement during decay rather than during peak fire. Steel structures face destructive tensile forces during contraction that can exceed the compressive forces experienced during heating. Mass timber presents particularly complex behaviour that may never truly enter a cooling phase without proper design considerations.

Perhaps most fascinating is how thermal boundary conditions transform as fires decay. When dense smoke thins, radiation patterns change dramatically, creating heat transfer scenarios that standard models fail to capture. These insights aren't just academic—they're essential for performance-based engineering approaches that prioritise realistic structural behaviour throughout a fire's entire timeline.

Andrea was kind enough to share these papers with me:

- Defining the fire decay and the cooling phase of post-flashover compartment fires: https://doi.org/10.1016/j.firesaf.2023.103965
- ⁠Thermal characterisation of the cooling phase of post-flashover compartment fires: https://doi.org/10.1016/j.ijthermalsci.2024.108933
- ⁠More information about FRISSBE project and team: https://www.frissbe.eu/

And I can shamelessly plug one of our own: https://onlinelibrary.wiley.com/doi/abs/10.1002/fam.2735

Cover image from experiments with Danny Hopkin that we have discussed here: https://www.firescienceshow.com/172-lessons-from-mass-timber-experiments-with-danny-hopkin/

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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 my personal view, an alarming truth about building fire safety lies in the gap between what's designed and what actually works in a building. After conducting 1000+ hot smoke tests in 200+ buildings, my experience is that most (maybe even 90%) of buildings had deficiencies in their smoke control systems, with 30% experiencing issues significant enough to potentially endanger occupants during a real fire. But it's not just about the problems. Good news - we have solutions.

Hot smoke testing stands as a powerful, yet underappreciated methodology that reveals what standard commissioning simply cannot. By creating controlled fires using methylated spirits and specialized smoke machines, we can observe how an entire building's safety ecosystem responds under fire conditions. The results are often eye-opening: systems operating in the wrong sequence, air flows disrupting smoke layers, pressurization fighting extraction, and critical components failing to activate when needed.

The most dangerous issue we encounter involves systems that don't "lock" to the first activated detector. This programming error causes safety systems to operate in areas far from the actual fire while leaving the fire location unprotected – a potentially life-threatening situation that's surprisingly common but easily fixable. Other frequent problems include excessive air velocity disrupting smoke buoyancy, extraction systems operating out of sequence, and auxiliary systems working against each other rather than in harmony.

What makes hot smoke testing so valuable is that it bridges the gap between aspirational safety (what designers intended) and actual safety (what the building delivers). Almost all identified issues can be corrected during commissioning, making this one of the most cost-effective safety investments possible. While the process may be disruptive and demanding, the alternative – discovering these failures during an actual emergency – is unthinkable.

Connect with me on LinkedIn to discuss implementing this approach in your projects and ensure your buildings aren't just designed for safety on paper, but truly deliver it when it matters most.

Recommended complimentary podcast episodes:

• https://www.firescienceshow.com/136-fire-fundamentals-pt-6-the-fire-automation-in-a-building/
• https://www.firescienceshow.com/033-science-theatre-or-engineering-polish-take-on-hot-smoke-test-with-piotr-smardz-and-janusz-paliszek/

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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 we stick a thermocouple into a fire? The answer is surprisingly complex and has profound implications for fire safety engineering. In this deep-dive episode, Dr. David Morrisset from Queensland University joins Wojciech to unravel the science of fire measurements that underpins every experiment, test report, and dataset in our field.

The conversation reveals a critical truth often overlooked by practitioners: measurements don't capture reality directly - they capture the interaction between our instruments and fire phenomena. When a thermocouple reports a temperature, it's actually measuring its own thermal equilibrium, not necessarily the gas temperature we assume it represents. This distinction becomes crucial when using experimental data to validate models or make engineering decisions.

The hosts explore various measurement techniques - from temperature and flow measurements to heat flux gauges and oxygen consumption calorimetry - detailing their underlying principles, practical challenges, and hidden assumptions. David shares fascinating insights from his research, including innovative approaches to extracting meaningful data from noisy mass loss measurements and using high-resolution temperature fields to calculate heat fluxes without traditional gauges.

This episode offers essential context for anyone who reads research papers, interprets test reports, or uses experimental data in their practice. By understanding the nuances of how we measure fire phenomena, engineers can better evaluate the quality and applicability of experimental results, recognise their limitations, and ultimately make more informed safety decisions. Whether you're conducting experiments or applying their results, this conversation will transform how you think about the data that drives our field.

I've received a bunch of papers from David to share with you, here we go:

1. Data smoothing - particularly around things like the MLR. This is covered in many papers, and you can start with: https://linkinghub.elsevier.com/retrieve/pii/S0379711222000893
2. The "blue light method" was discussed in the podcast with Matt Hoehler from NIST - I came up with the same kind of effect but with PMMA (using black light instead of blue light) - https://doi.org/10.1016/j.firesaf.2025.104425
3. We did some work on characterising the thermal boundary layer generated by gas-fired radiant panels. https://doi.org/10.1016/j.firesaf.2023.104013
4. In the flame spread work, I did use temperature data to approximate the heat flux acting at the surface https://doi.org/10.1016/j.firesaf.2023.104048

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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 2018 Camp Fire in Paradise, California serves as a haunting reminder of how rapidly wildfires can overwhelm communities. We have not known anything like it - the flames raced through Paradise at four miles per hour, 30,000 residents had mere minutes to evacuate, and many couldn't escape in time. What happens when the fire goes worse than worst case scenario, but still people need to escape? How do we protect lives when escape routes are blocked by fire or gridlocked traffic?

Dr. Eric D. Link, NIST's researcher in the groundbreaking ESCAPE Project, takes us deep into these critical questions. The project's findings reveal how temporary refuge areas saved over 1,200 lives during the Camp Fire when people couldn't outrun the flames. These ad-hoc safe zones – parking lots, road intersections, and open spaces with reduced fuel loads – provided crucial protection when primary evacuation plans collapsed.

The conversation explores how communities can prepare for these worst-case scenarios by pre-identifying Temporary Fire Refuge Areas (TFRAs) throughout their neighbourhoods. Unlike traditional wildfire safety zones that require enormous clearance, TFRAs offer practical, achievable alternatives that acknowledge the realities of wildland-urban interface communities. The key insight? Even perfect evacuation plans can fail when fires move too quickly, so communities need backup options.

We also delve into the concept of "decision zones" for evacuation planning, the challenges of "no-notice fire events," and the potential for developing dedicated fire shelters that could protect large groups during extreme fire conditions. With climate change intensifying wildfire behavior and more communities at risk, these lessons from Paradise provide crucial guidance for protecting lives when evacuation isn't possible.

Read further on the ESCAPE project findings at the amazing NIST repository (in general, reading the NIST repository is a good life advice :)): https://www.nist.gov/publications/wui-fire-evacuation-and-sheltering-considerations-assessment-planning-and-execution-0

NIST dedicated webpage with more resources, especially for community managers: https://www.nist.gov/publications/wui-fire-evacuation-and-sheltering-considerations-assessment-planning-and-execution-0

Trigger boundaries podcast episode: https://www.firescienceshow.com/156-trigger-boundaries-with-harry-mitchell-and-nick-kalogeropoulos/

Cover image credit: On the morning of November 8, 2018, the Camp Fire erupted 90 miles (140 kilometers) north of Sacramento, California. By evening, the fast-moving fire had charred around 18,000 acres and remained zero percent contained, according to news reports. The Operational Land Imager on Landsat 8 acquired this image on November 8, 2018, around 10:45 a.m. local time (06:45 Universal Time). The natural-color image was created using bands 4-3-2, along with shortwave infrared light to highlight the active fire. Officials evacuated several towns, including Paradise. They also closed several major highways.
NASA, Joshua Stevens - https://earthobservatory.nasa.gov/images/144225/camp-fire-rages-in-california

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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.