Shows
Fire Science Show238 - Fire Fundamentals pt. 19 - Defining fires in your modelsWelcome 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 f...
2026-02-1156 min
Fire Science Show227 - The differences between EV and ICEV fires in car parksA viral clip of an EV igniting was what started my worries about safety in car parks I have been designing. Are we ready for fast growing fires? Since 2019 I've learned and studied a lot, I've relaxed on some aspects of it and was able to identify they areas where a lot more engineering considerations should be placed. In this episode I would like to take you inside the engineering choices that shape outcomes: ceiling height, smoke control, structural details, and how fast systems wake up when seconds matter. Instead of arguing EV versus ICE, we look at what...
2025-11-1954 min
Fire Science Show216 - What do we measure and how? with David MorrissetWhat 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...
2025-08-271h 04
Fire Science Show192 - Fire Fundamentals pt. 14 - Jet fan systems for car parksJet-fan systems effectively control smoke in car parks by creating directed airflows that transport smoke from one point to another, similar to how longitudinal ventilation works in tunnels. These systems offer cost-effectiveness and simplicity by eliminating ductwork while providing powerful smoke management capabilities when properly designed and understood.• Jet Fans create momentum transfer through air entrainment rather than directly moving smoke• Two distinct operational modes exist: smoke clearance (reducing thermal stress) and smoke control (maintaining clear firefighter access)• Systems require careful balancing of extraction capacity with Jet Fan thrust force• Optimal design typically requires CFD mode...
2025-03-1242 min
Fire Science Show190 - Car park fires review with ZahirWith the emergence of electric vehicles, fire safety and dynamics have entered a new domain, raising crucial questions about existing protocols, design fires and data gaps. Today, our Wojciech Wegrzyński welcomes Zahir, Associate Prof. at University Putra Malaysia, to discuss the findings from their latest papers, compare methodologies, and highlight the differences between traditional combustion engines and electric vehicles. The conversation covers various topics, from the nuances of fire dynamics to the importance of context in risk assessment. Zahir shares his extensive experience studying vehicle fires, including the evolution of electric vehicle dynamics that users should ne...
2025-02-2651 min
Uncovered Witness: Fire Science RevelationsS3E01 | Legal framework of the buildingWelcome to the third season of Uncovered Witness: Fire Science Revelations. In the third season, the focus shifts from a purely technical analysis of building design and fire safety measures to an understanding of the intricate legal and regulatory landscapes that govern compliance. Across four in-depth episodes, experts in law, engineering, insurance, and forensic fire research collectively shed light on how buildings achieve (or fail to achieve) legal compliance and genuine safety. These conversations highlight the ongoing tension between prescriptive codes and performance-based solutions, the evolving complexity of building materials and construction methods, and the m...
2024-12-1743 minUncovered Witness: Fire Science RevelationsS3E02 | Building defectsThis episode of Uncovered Witness: Fire Science Revelations, Season 3, delves into the challenging process of defining and identifying building defects, particularly in the realm of fire safety. We emphasize the complexity and multifaceted nature of what constitutes a building defect. Joined by experts from various disciplines, including fire safety, law, and insurance, the episode unravels different perspectives on defects, their implications, and their compliance with building regulations. The discussion includes key insights from experts like Mario Lara Ledermann from Halliwell Fire Research UK, Joanna Grant from Fenchurch Law Ltd, and Garteh Bowers and Richard Gough from McLarens. T...
2024-12-1739 minUncovered Witness: Fire Science RevelationsS3E03 | The pyramid of solutionsIn this episode of 'Uncovered Witness: Fire Science Revelations,' we investigate the complexities of identifying and fixing building defects. The episode begins by outlining the stages involved, from the initial detection of a defect to selecting an appropriate fix. The host highlights the roles and responsibilities of key stakeholders such as developers and insurers, highlighting the challenges of defining what constitutes a defect and determining whether insurance policies cover it. Early responsibility lies with the developer, while latent defect policies can come into play later on, though these often include many exclusions that need careful navigation. ...
2024-12-1746 minUncovered Witness: Fire Science RevelationsS3E04 | Litigation processIn the final episode of "Uncovered Witness: Fire Science Revelations," Season 3, the series explores how defects can arise, the multidisciplinary approach needed to address them, and the pivotal role of loss adjusters and expert witnesses in resolving such conflicts. The process begins with identifying the building defect, which is not merely about identifying something built incorrectly but involves complex definitions based on legal and insurance policies, potential dangers, and regulatory compliance. Experts shed light on the nuanced engagement needed from the involved parties and the broad implications for developers, insurers, and engineers.The next stage...
2024-12-1747 min
Fire Science Show180 - Fire Fundamentals pt. 12 - Pressurization systemsIn this episode of fire science fundamentals, we cover the pressurisation systems. These are smoke control solutions used to prevent smoke from accessing protected spaces, by creating an overpressure in those spaces. Although the idea is very simple, its execution is far from that. Pressurization systems need to work in two distinct states – when all doors to the protected space are closed (over pressurization state), and when some openings are open (flow-path state). In this episode, we cover:· What are pressurization systems and why do we use them in buildings;· Static and dynamic pressure;
2024-12-0448 minUncovered Witness: Fire Science RevelationsS2E02 | Response to fire cues and group influenceWelcome to Season 2 of Uncovered Witness: Fire Science Revelations! This season, the show's theme is Humans as part of a fire safety engineered system. In this series, we will unravel our understanding of human behaviour in fires and how this complex behaviour may be accounted for in the fire-safe design of buildings. Our understanding of the occupant response, decision-making process and biases may influence our design of exits and improve (or impede) the egress process. In the second episode of the series, we focus on the actions taken by the occupants from the moment they r...
2024-08-1240 minUncovered Witness: Fire Science RevelationsS2E04 | Familiarity and debunking the myth of PanicWelcome to Season 2 of Uncovered Witness: Fire Science Revelations! This season, the show's theme is Humans as part of a fire safety engineered system. In this series, we will unravel our understanding of human behaviour in fires and how this complex behaviour may be accounted for in the fire-safe design of buildings. Our understanding of the occupant response, decision-making process and biases may influence our design of exits and improve (or impede) the egress process. In the final episode of Season 2, we continue the discussion on familiarity, which is explained through the theory of affiliation. W...
2024-08-1239 minUncovered Witness: Fire Science RevelationsS2E03 | Behavioural sequence and role-rule modelWelcome to Season 2 of Uncovered Witness: Fire Science Revelations! This season, the show's theme is Humans as part of a fire safety engineered system. In this series, we will unravel our understanding of human behaviour in fires and how this complex behaviour may be accounted for in the fire-safe design of buildings. Our understanding of the occupant response, decision-making process and biases may influence our design of exits and improve (or impede) the egress process. This episode is all about human behaviour theories - useful concepts that allow us to explain some of the behaviour o...
2024-08-1243 minUncovered Witness: Fire Science RevelationsS2E01 | Pre-evacuation time distribution in fire safety engineeringWelcome to Season 2 of Uncovered Witness: Fire Science Revelations! This season, the show's theme is Humans as part of a fire safety engineered system. In this series, we will unravel our understanding of human behaviour in fires and how this complex behaviour may be accounted for in the fire-safe design of buildings. Our understanding of the occupant response, decision-making process and biases may influence our design of exits and improve (or impede) the egress process. In the first episode of this series, we cover the approach used to account for complex human behaviour in assessing t...
2024-08-1240 min
Fire Science Show163 - Fire Fundamentals pt 11 - Soot in Fire Safety EngineeringSoot is perhaps the most complex product of combustion, and at the same time one of the most profound for our everyday fire safety engineering. The topic of soot is not getting much love in the world of fire science, so I’ve chosen to give you a broad introduction to this subject. In this episode of fire fundamentals we will go through:· Soot creation from chemical perspective;· Soot creation from practical perspective;· Soot effects on radiation, toxicity and obscuration;· Extinction coefficient and specific extinction coefficient;· Soot yield and surrogate value of soot yield fo...
2024-08-0750 min
Fire Science Show162 - Experiments that changed fire science pt. 9 - Jin's experiment on visibility in smokeIn this episode of Experiments that Changed Fire Science we cover T. Jin’s experiments on the visibility in smoke – two experiments carried out in 1970 and 1971 in Japan that truly changed the way how we model fires and how we design fire safety in our buildings.This episodes presents my recollection of Jin’s experiments, based on the published work – the seminal paper at the IAFSS in 1997 (https://publications.iafss.org/publications/fss/5/3/view/fss_5-3.pdf) and the original material published in Japanese in 1970 and 1971:Jin, T. (1970). Visibility through Fire Smoke (I). Bulletin of the Fire Pre...
2024-07-3141 minUncovered Witness: Fire Science RevelationsThe Expert Witness with Kristen E. LangeIn this episode of The Uncovered Witness, I've invited Kristen E. Lange from Ogden Murphy Wallace P.L.L.C. In her expertise, Kristen has worked on court cases related to fire safety; in those cases, she has worked with expert witnesses who were fire safety engineers. Trying to tap into this experience, we try to identify "who" is the expert witness? What role are they in legal proceedings, and how is their expertise presented? Also, what makes an outstanding expert witness? This show is produced by the Fire Science Media for Halliwell Fire Research. Executive producer...
2024-06-1346 minUncovered Witness: Fire Science RevelationsMeans of Escape pt. 1 - The Exit CapacityIn this mini-series of the Uncovered Witness - Fire Science Revelations, we cover the subject of the means of escape - the technical solutions in our buildings meant to allow for human evacuation in case of a fire.In the first episode of the series, we discuss exit capacities and flow rates. How do we know how many people can fit in the building? What do the models look like, and where did they come from? What data do we have at our disposal, and how relevant is it?We also refer to the tragic...
2024-04-1050 minUncovered Witness: Fire Science RevelationsMeans of Escape pt. 2 - The Building AutomationIn this mini-series of the Uncovered Witness - Fire Science Revelations, we cover the subject of the means of escape - the technical solutions in our buildings meant to allow for human evacuation in case of a fire.In the second episode of this mini-series, we cover the fire engineering solutions for building automation that influence the evacuation processes in the buildings. Reflecting on the Beverly Hills Supper Club tragedy, where the systems were not present, we try to evaluate what tools the engineers have in their toolbox.In this episode, we cover some fundamental...
2024-04-1045 minUncovered Witness: Fire Science RevelationsMeans of Escape pt. 3 - The Good and the Bad SignageIn this mini-series of the Uncovered Witness - Fire Science Revelations, we cover the subject of the means of escape - the technical solutions in our buildings meant to allow for human evacuation in case of a fire.In the third and final episode of the mini-series, we discuss what makes or breaks the design of an evacuation sign. While it may seem like a simple design choice (make it green and make the arrow point in the correct direction?), there are, in fact, many elements that influence the human perception of the sign. We tap into...
2024-04-1044 minUncovered Witness: Fire Science RevelationsTrailer episode for the Uncovered Witness: Fire Science RevelationsMy name is Wojciech Węgrzyński. I'm a professor at the Building Research Institute in Poland, a fire safety engineer, and an enthusiast for fire. In my podcast, Fire Science Show, I interview experts in the field every week on the newest and best knowledge about fire. Catering to fresh and seasoned engineers, it provides unparalleled professional development for any practising FSE.In this podcast, I am joining HALLIWELL Fire Research to provide a more fundamental insight into fire science. With content that does not require any prior knowledge, we hope to guide the listener from th...
2024-04-0805 min
The Smart Passive Income Online Business and Blogging PodcastHow a Small Niche Makes a Big Profit with Wojciech Wegrzynski#735 Many of us believe we need to reach millions of people to make a living online. We then fall into the trap of going as broad as possible with our content. But what if a small targeted audience is actually a major asset? In this episode, we hear all about Wojciech Wegrzynski's incredible journey. His podcast, the Fire Science Show, averages just five hundred downloads per episode. But here's the thing—Wojciech's revenue from sponsors is already surpassing his engineering job income! Listen in because this episode brings together some of the most important topics we always discuss here on...
2023-11-2237 min
Fire Science Show126 - Where is the challenge with tunnel smoke control? with WojciechI'm known for my rant about critical velocity concept in tunnel ventilation systems, and I tried to really control myself and not go into podcast with it :) But in recent weeks, when I was enjoying sake at IAFSS in Tsukuba two important things happened. We have received the PASCAL award from the Polish Ventilation Association for the best ventilation design in Poland - our S2 Warsaw Ring tunnel project. The second was the invitation from the Conference of European Directors of Roads to talk about my view on challenges in tunnel ventilation. So it seems our design in this...
2023-11-0844 min
Fire Science Show116 - Fire Fundamentals pt. 4 - Natural and Powered Smoke Vents with WojciechIt is time for some engineering fundamentals in the show. This time in the fire fundamentals series we delve into the details of natural and powered smoke ventilators - what they are, how they work, how they are tested and what interesting mechanics impact their performance in fire.I hope this episode is valuable for all engineers who would love to know how the devices they place in their design are tested and qualified for use in fire safety. It should also be a great way for fire scientists to broaden their horizons and learn about very...
2023-08-3046 min
Fire Science ShowQA5 - Brainstorming fire safe Mars habitats with Ruben van Coile, Jaime Cadena Gomez and Szymek MatkowskiThis time we try out something new! Instead of interviewing experts on subjects of their expertise, this time I took world-class risk specialists for a brainstorming session. And while sitting together, we discussed something out of this world - the fire safety of Mars habitats. This podcast episode is literally a recording of the conversation between the panellists, it is very unscripted and lightly edited. I really hope you will feel like a part of this conversation, and if you would like to voice your ideas - share them on socials or mail them directly to me. I...
2023-07-051h 00
Fire Science Show100 - Fire Fundamentals pt. 3 - Smoke plumes (and other flow phenomena) with WojciechThis week we cover the fundamentals of smoke flow (proliferation!), entrainment and smoke plumes. All the basics that impact the spread of the smoke in our buildings. You will learn:the ideal gas assumption for a smoke mixtureturbulent nature of fire-induced flowsaxisymmetric plume models and their originsspill plumeswindow and door plumesbasics of smoke controlIf you would like to read up more, please resort to:Review of plume modelsEnclosure Fire Dynamics - Karlsson, Quntiere, JohanssonFluid Mechanics Aspects of Fire and Smoke Dynamics in Enclosures - Merci and BejiProbably the best thing about visibility in smoke I...
2023-05-1057 min
Fire Science ShowQA4 - Wojciech in Smart Firefighting podcast episode 151 - fire science, innovation and built environmentThis week in place of a normal episode I would like to share an interview I gave to my friend Kevin Sofen in his podcast. In this episode I am interviewed by Kevin on the science of fire, how I understand the built environment and the challenges it brings. Kevin asks me some really tough questions, like what the fire-safe world is, and how to innovate in space of the fire engineering. I have highly enjoyed this discussion, and if you have not heard it at the Smart Firefighting Podcast, I hope you will enjoy it as well here!
2023-04-2654 min
Fire Science Show070 - Fire resistance is whatever you want it to be with Piotr TurkowskiToday we talk fire resistance, but unlike you have ever heard. Join me and Dr Piotr Turkowski - two fire laboratory professionals in an honest discussion about their craft. The challenges in standardization and committee work, discoveries in laboratories that are very tough to implement in the test method design, and sometimes unscientific approaches which are necessary for a market consensus. All the challenges that make us view fire resistance in a different way than you may have. Here are some resources for further learning:EGOLF webpage, and a direct link to EGOLF R...
2022-10-0555 min
Fire Science Show069 - Challenging fires at the wildland-urban interface (WUI) with Michael GollnerWhy so many researchers are spending their time tackling fire issues at the Wildland Urban Interface (WUI)? What is so challenging about this? We always lived near nature, why today this emerges as one of the 'hottest' topics of fire science? As my today's guest Prof. Michael Gollner says - you need a very bad combination of weather and vegetation conditions to create a really bad fire. However, these conditions are occurring more and more often - in California they are not even considering fire seasons anymore, but wildfires become a threat all year round. I don't want to...
2022-09-2858 min
Fire Science Show068 - Human walking speed and factors that influence it with John GalesWhat factors influence the walking speed of an occupant? Is it just their physiology and crowd density? It seems it is more complicated than that (as most things are in fire science...). Dr John Gales of York University takes me on a journey through their extremally interesting research on anthropomorphic data and movement speeds, which they have been extensively carrying through the last years. You will learn why the crowd at a football match will have a different characteristic than one attending American football (handegg?). Why evacuation is quicker in torrential rain than in fire, and how stimuli may...
2022-09-2158 min
Fire Science Show067 - Next-gen smoke control experimental facility and a digital twin with Grzegorz KrajewskiWe've felt a bit awkward about how FSE handles smoke control in corridors. If you look closely into common practices, they rarely do include impressive engineering - more often you see some 'tips and tricks' that make the CFD simulations work out and systems are accepted. Doors opening/closing in specific timeline points, heat source sizes or soot generation parameters... I agree it does not necessarily mean that all the systems are designed wrongfully, or they do not provide safety... but in fact - how can we tell what they provide if we are not evaluating them in a...
2022-09-1435 min
Fire Science Show066 - Fire Safe Use of Wood in Buildings with Andy BuchananI wonder if we will be ever able to say: we know exactly how to build fire-safe buildings with mass timber. However that day may never come, each day of research brings us a little bit closer to achieving this goal. And some days - like the one in which Andy Buchanan and Birgit Östman published their open access handbook on fire-safe use timber, we definitely leap towards success! In today's episode, I'm interviewing prof. Andy Buchanan on his thoughts on fire-safe use of timber, in relation to the handbook published recently (Book website). W...
2022-09-0757 min
Fire Science Show065 - Understanding mesh sensitivity and model uncertainties with Jason FloydWill a higher resolution mesh make my CFD more accurate? That is a harmless question, and most of us would tend toward 'I guess yeah'. But let us try and unpack this. Into atoms! What does higher resolution mean? How exactly solver deals with increased spatial discretization and what are the exact consequences of that? What is a high resolution for a tiny orifice and what is a high resolution for a road tunnel? But it gets better... What makes CFD more accurate? Is it better alignment with experimental data - if so, do you know the experimental and...
2022-08-3155 min
Fire Science Show064 - Heat stress in fires - from inside and outside with Denise Smith and Gavin HornThis amount of heat flux for this amount of time, routine conditions, check, done. This is how I used to do my engineering and tenability assessment related to heat stress... up till today when prof Denisse Smith and prof Gavin Horn took me on a bumpy journey into the physiology of humans in fire conditions and in personal protective equipment (PPE). It is astonishing, that the stress on the body of the firefighter may be as great from the fire as from their own heat generation due to work being done. If you think about it - it is...
2022-08-241h 02
Fire Science Show063 - Why do we need a handbook of fire and the environment with Brian Meacham and Margaret McNameeDo we need another fire handbook? If so, what handbook would that be? I guess a question like this must have gone through Brian Meachams' mind when he got the idea for a handbook of fire and environment. And he got a brilliant co-editor - Margaret McNamee to support him in this tough work. The effect - a complete piece on the environmental effects of fires - but beyond just smoke and contamination. A piece that deals with the complexities of the modern world, sustainability and resilience. One that considers product lifecycle assessment as much as the toxicity of...
2022-08-1755 min
Fire Science Show062 - BIM (not only for fire) with Peter Thompson and Rino LovreglioIt does not matter if you hate or love BIM, does not matter if you use it daily or have no idea what it is... Building Information Modelling will be an important part of our engineering future and we better get used to it. In this episode, I talk to Peter Thompson of GHD, who had previously worked at Autodesk as a Revit developer, and prof. Ruggiero Lovreglio, a teacher of computer methods in design at Massey University. Having two experts - one a developer, and the other a user of BIM I try to get balanced answers on w...
2022-08-1059 min
Fire Science Show061 - Glazing in fire with Yu WangThe relation between ventilation conditions and fire severity is quite a fundamental one. You don't even have to be a fire safety engineer to realize that more air means a bigger fire. But how does air get into the compartment fire in the first place?Through broken windows of course!And here we come to the subject of today's episode. Because with all the considerable improvements in glazing technologies for building facades, is it really okay to assume that the glazing has failed and all we are left is a giant hole that allows the...
2022-08-0347 min
Fire Science Show060 - How PV panels change the fire behaviour of roofs with Jens Kristensen[March 2023 update] The Thesis PDF is finally available! Check it here: https://www.researchgate.net/publication/369141515_Fire_risk_associated_with_photovoltaic_installations_on_flat_roof_constructions_-_Experimental_analysis_of_fire_spread_in_semi-enclosures If a PV panel is fire safe, and the roof is fire safe, what is the outcome of a panel placed on the roof? Not a great surprise that merging two things that meet their requirements within their respectable eco-systems gives a not such a fire-safe outcome after all... This is the difference between considering systems versus product characteristics, and in...
2022-07-2743 min
Fire Science Show059 - Residential fire safety with Dan Madrzykowski and Charlie FleischmannHow much the fire scene at households has changed over the last 30 years? Why modern furniture burns worse than one made with wood, cotton and other natural materials? And what does that mean to firefighting? What challenges do modern firefighters face fighting residential fires... There is so many questions to be asked about residential fires, and in this episode, I answer a lot of them with the firefighting research legends - Dan Madrzykowski of the UL Fire Safety Research Institute and professor Charlie Fleischmann from the University of Canterbury. After listening to this episode you must check...
2022-07-2055 min