260 - Fire safety in a carbon budget with Cecilia Wetterqvist and Axel Mossberg

260 - Fire safety in a carbon budget with Cecilia Wetterqvist and Axel Mossberg

A carbon budget can feel like a hard wall in modern building design, and once you treat CO2 as currency, everything starts competing for a slice of it. The problem is that fire safety systems often show up in those spreadsheets only as a penalty: extra embodied carbon for sprinklers, alarms, and protection. What gets ignored is the payoff. A serious fire can erase years of “sustainable” choices through demolition, replacement materials, repair labor, and lost building value, all with a very real carbon footprint. We sit down with Swedish researchers Cecilia Wetterqvist (Lund University and Bengt Dahlgren Fire Research) and Axel Mossberg (Bengt Dahlgren Fire Research) to connect fire safety engineering with life cycle assessment (LCA), climate declarations, and green building certification thinking. We talk honestly about system boundaries, early design lock-in, why “50-year” assumptions can be misleading, and how reuse projects can be both a climate win and a detailing challenge that changes maintenance and risk. The heart of the conversation is a translation tool: turning fire risk into the same unit sustainability teams already use, kilograms of CO2e per square meter. Using incident statistics and damage categories, the method estimates expected fire-related emissions, including the big driver most models miss: replacement. The result can flip decisions on their head, especially for larger commercial buildings where sprinklers may reduce expected lifecycle carbon rather than increase it. If you are looking here for more resources, you know I got your back: * Mossberg A. et al., A methodology for the integration of fire risk in building life cycle analysis [https://www.sciencedirect.com/science/article/pii/S0379711225002656?via%3Dihub] * Wetterqvist C. et al., Sustainability and fire safety decisions in the design process: Overview and two Swedish building projects [https://www.sciencedirect.com/science/article/pii/S0379711226000354?via%3Dihub]  * McNamee M. et al., Challenges and opportunities for reuse of products and materials with fire safety requirements – A Swedish perspective [https://www.scopus.com/pages/publications/85165132487?origin=resultslist] ---- 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.

259 - Communicating fire science with politicians with Birgitte Messerschmidt

Fire safety is a tough “product” to sell because the best outcome looks like nothing happened. That’s exactly why we sat down with Birgitte Messerschmidt (NFPA) to talk about communicating fire science to politicians, regulators, grant bodies, and other people in positions of power who can approve policies, permits, and funding, often with only a few minutes to spare. We share what changes when your audience is nontechnical, busy, and sometimes driven by incentives that do not neatly match engineering logic.  We get practical about preparation: mapping who actually holds the decision power, building an elevator speech, and using storytelling so your message sticks. We also unpack the role of media and “sensation” in shaping political priorities, using electric vehicle fire headlines as a real example. Instead of amplifying fear, we talk about framing the issue as a changing fire landscape: new materials, tighter buildings, batteries, and evolving hazards that demand updated fire safety engineering.  Then we go into the hard parts: how experts can get pulled into political fights, how soundbites get cherry-picked, and when the right move is to say less, not more. We also tackle ethical communication after tragedies, focusing on respect for victims and clear intent to prevent repeat losses. Finally, we wrestle with risk communication, why “it could happen” derails risk-based design, and how to acknowledge emotion while bringing people back to facts. ---- 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.

258 - e-mobility fires in trains with Adam Barowy

A battery fire on a train is not “just another small fire.” When a lithium-ion battery in an e-scooter or e-bike fails, the rail car can behave like a long pipe that moves smoke fast, limits escape options, and compresses decision-making into minutes. We sit down with Adam Barowy from UL Research Institutes FSRI to unpack new full-scale passenger rail car burn tests using real micro-mobility devices and realistic storage locations. We talk through what thermal runaway looks like before flames, why that venting phase is a crucial warning sign, and what changes once flaming ignition starts. Adam shares the data that surprised even seasoned fire researchers: smoke can spread from one end of the car to the other in about 30 seconds after flaming ignition, floor-level visibility can collapse in roughly two to three minutes, and toxic exposure can become a serious egress limiter on the same timescale as train stopping and evacuation. We also zoom out to the operational and societal reality. Rail operators want to support first mile last mile travel and riders who depend on e-mobility for work, yet they need policies that actually reduce risk. We cover practical options like limiting device size, avoiding carriage in the first or last car when exits are constrained, improving passenger education, requiring battery safety certifications, and exploring segregation strategies that keep devices away from passengers without pushing the problem underground. I promised you links, so here they are: * Summary of the research on trains and batteries [https://ul.org/press-releases/ul-research-institutes-releases-new-report-examining-the-fire-safety-hazards-of-e-mobility-devices-on-passenger-railcars/]  * The full report [https://fsri.org/research-update/report-examines-fire-safety-hazards-e-mobility-devices-passenger-railcars]  * Li-Ion battery safety guide [https://fsri.org/lithium-ion-battery-guide]  Cover image created from pictures from their report linked above! Following Adam's recommendation and taking your resources for a creative spin :) ---- 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.

257 - Fire Fundamentals pt. 21 - Radiation with Simo Hostikka

In this episode of fire fundamentals we sit down with Professor Simo Hostikka from Aalto University to cover radiation in fires, both from the angle of physical phenomena and ways to model it. In this episode we cover following topics: *  feel less mysterious, from blackbody basics and role of radiation actually does inside the CFD N-S equation.  * Spectrum and emissivity to real engineering outcomes like heat flux, tenability * Radiation’s two roles in fire CFD: target heat flux and the gas energy source term  * Emission versus absorption and why Kirchhoff’s law is spectral, not just a single number  * Spectrum intuition using Planck, Wien’s law, and why T to the fourth explodes heat flux  * View factors as a hazard mental model for layers, panels, and distance effects  * Why gases are strongly non-gray while soot often looks smooth and easier to approximate  * How FDS uses the finite angle method, why 104 directions exists, and how updates are staged in time, how to manage spatial and temporal resolution of the radiation  * Ray effect and numerical diffusion, when you can see the error and when you cannot  * Other radiation models such as Monte Carlo, and when they are worth it. ---- 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.

256 - Modelling turbulent combustion in fire CFD with Bart Merci

While we can get pretty far with a very simple approximation of what a fire is in our fire cfd, at some point our simplications are not enough. And there is a plenty of features and phenomena, for which we simply need a better tool to handle -  carbon monoxide, soot, extinction, flashover behavior, and what happens when ventilation disappears. At the IAFSS symposium, we sit down with Professor Bart Merci (Ghent University), fresh off delivering the Howard Emmons Invited Plenary Lecture, to talk about what it really takes to model turbulent combustion in real fires without asking practitioners to become full-time combustion scientists. We start with the engineering reality check: you do not get unlimited mesh resolution, unlimited runtime, or the luxury of endless sensitivity studies. As Bart says - "you need to pick your battles". That practical constraint shapes everything, from whether LES is a smart choice to how you treat the “unseen” physics inside a CFD cell. Bart breaks down turbulence in plain terms, explains why the largest eddies dominate entrainment and smoke movement, and shows how mesh decisions can quietly decide whether LES outperforms unsteady RANS in practical smoke control and compartment fire problems. Then we go deep on sub-grid combustion models. We unpack why infinitely fast chemistry can be acceptable in well-ventilated flames yet collapses in under-ventilated conditions, where toxicity, soot, and extinction dominate the risk picture. Bart explains a finite-rate, autoignition-informed approach that uses detailed chemistry offline to tune simplified reactions, then applies flamelet concepts and turbulence measures to predict reaction rates and species production inside each cell, including ignition and extinction behavior without relying on a guessed “critical flame temperature.” We close with what’s next: validation in compartments, microgravity as a brutal test of “universality,” and why advanced non-intrusive diagnostics could finally improve near-wall heat transfer and flame-surface interaction. If you care about CFD, FDS modeling limits, fire dynamics, and the future of practical fire safety engineering, you’ll want this one.  If you would like to read more on the topic, here is Bart's paper that accompanied his brilliant lecture [https://www.sciencedirect.com/science/article/abs/pii/S0379711226000330]. Figure 3 is what we discuss at the end of the episode. ---- 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.