Fire Safety Engineering at Aalto

We had a pleasure to host an enthusiastic 9th grader for two weeks. Below you see his fantastic report. Thank you Leo for your help, participation, and insightful comments during your stay!

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Report of my TET-period

Author: Herold Leo
Recipient: Aalto University
Date: Friday, 13.11.2026
Event: TET-Period
Framework: School and education
Place: Aalto University, civil engineering department
Keywords: University, engineering, education.

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    Abstract

I had the opportunity to spend two weeks at Aalto University to complete my TET period, a work experience program that gives me something to put on my first CV. These past two weeks have been truly remarkable. I’ve learned a few existential truths about life.

While all burning is oxidation, not all oxidation is burning. Thus, while oxidizing water is possible, burning it is not.

The people at Aalto are very nice and supportive. Furthermore, the food in the cafeteria is unbelievably delicious and only costs €3.10. While that is more expensive than my school’s free lunch, it won’t completely drain my 15-digit bank account balance. Still, it is just enough to make each customer value their food a little bit more when they pay for it themselves.

And that coffee machine? That is the best thing in the whole complex. It offers free coffee whenever you want, exclusively for staff members—including me, even though I still got the student price for lunch.

The past two weeks have been very fascinating, though they would have been considerably less so if we removed every factor that made them fascinating. Then, we would end up with something completely different from a university

I praised the place for a reason, though we should still bring up all the facts for a balanced conclusion. First of all, the automated chalkboard mover on the left side of lecture hall R1 makes quite a loud noise when used. It sounds like someone needs to oil it soon. Speaking of lecture hall R1, I also noticed that the front row does not feature a writing desk like all the other rows do. This might make life harder for people sitting in the front, since they cannot take notes properly. Furthermore, some of the computers are getting very old; in my opinion, they should be replaced with newer ones. They are also running such an outdated version of Windows that it would be reasonable to update it.

Another point is that my school doesn’t even have a big enough budget to buy a net for our ping-pong table—let alone a 27 km-long underground particle accelerator. Meanwhile, Aalto has the budget to buy instruments that can easily cost half a million euros, yet we supposedly live in a country of “equality.”

Everyone tends to think that universities are places of hardcore studying and intense research. Well, not at Aalto. Aalto is a place where you can take a 40-minute coffee break right after a 40-minute lunch break, and then go play around with an FT-IR spectrometer while listening to Linkin Park. To me, universities are chill places without intense studying or constant evaluation, unlike middle school.

There hasn’t been a single person who wasn’t nice, though that is only from my perspective. I might have gotten some people really annoyed. For example, one poor professor whose lecture I was visiting couldn’t properly finish his coffee during the break. It felt like every time he was about to take a sip, I asked a question and he had to put his mug down to answer me. It seemed like everyone else was taking notes on what he said, while I was taking notes on what he didn’t say.

Therefore, I wouldn’t be surprised if he wasn’t too thrilled to see me again in the future. I also asked someone what would happen if we placed a tornado in the middle of a forest fire, and kept another person from properly doing his work because I needed constant IT support in Microsoft Excel and later in Google Sheets. Speaking of which, my rate of productivity didn’t quite delight my dear professor, Simo Hostikka, either. I want to clarify that I wasn’t unproductive on purpose; I just couldn’t figure out how to make those charts in Excel. For anyone who doesn’t understand the struggle, I was supposed to make eight charts with four lines each, and I managed to make one chart with two lines—which was my entire accomplishment for the day.

I’ve been so happy throughout nine of the days during this period. Nine, and what about that one day off? That was the day spent in Excel and Sheets.

However, that brings us to another existential truth I discovered during these two weeks that I’d like to share with you:

You should be thankful for every second you aren’t messing with Excel, because any second could theoretically be spent in Excel.

And I learned that the hard way. I’m offering you the chance to learn it the easy way.

I’ve met a lot of different people there—including someone who thinks rocket science is simple, for instance, and another person who has been in the top 0.001% of Linkin Park fans according to Spotify. That is truly an honorable achievement.

This period has made some relatively rare things possible for me, such as using an FT-IR spectrometer and a cone calorimeter at the age of 14.

What does fire safety engineering look like from the perspective of a 9 grader?

Most of the time, fire safety is just executing an overly dramatic protocol and evacuating the entire complex simply because someone forgot to take their bread out of the toaster. It is also about trying to figure out how to produce a polymer that doesn’t burn—and once it’s found, sticking it to the walls so a fire won’t spread. I played a definitive role in this life-saving work by using FT-IR spectroscopy, which measures the reflectance of different materials across given wavelengths.

As a field of science, fire safety isn’t very visible in my daily life because all the things engineers design blend subtly into “normal” life. Still, it is completely necessary because an oxygen atom has six valence electrons, which means it is constantly trying to bond with other elements. Once it finally forms two covalent bonds, it successfully reaches a full octet. Therefore, firefighters and fire safety engineers are basically working against oxygen’s aggressive urge to bond with everything else. It is fascinating how oxygen keeps us alive while simultaneously trying to kill us. Ultimately, fire safety engineering is just studying how oxygen reacts with other things.

    Conclusions

Now, you might wonder: what was the best thing about Aalto? Well, there are actually two best things:

1. The legendary coffee machine with unlimited  coffee and hot chocolate (though it never fills your cup all the way…).
2. Everything and everyone around the machine.

Thank-yous go to:

• Simo Hostikka, for hosting this period and not raging upon realizing how bad I am at Excel.
• The person who helped me use Excel, for also not raging upon realizing how bad I am at Excel.
• Simonas Kaskelevicious, for not raging when I misclicked “Clear All” in the FT-IR software a couple of times before saving the results.
• Shanmugasundaram Dakshanmurthy for not raging when I made wrong conclusions about the physical properties of the sample wood and after finding out that I reported unwanted speech to Simo Hostikka.
• Suvi Holmsted, for giving the most interesting organic chemistry lectures I’ve ever attended (I know it is her job, but thank you anyway).
• Sina Bazrpash, for sharing the fact that we cannot burn water.
• Jukka Seppälä, for still answering my questions even though I frequently interrupted his coffee breaks.
• Joonas Jaaranen, for patiently waiting, clearly explaining how different bridges work, and answering my hypothetical scenarios about them.
• Hermanni Komaro, who also put a considerable amount of effort into helping me write this report.

It has truly been a pleasure working with all of you.

Posted by Simo Hostikka

Preparing a plenary lecture was actually a lot of work. I had never done such a thing in this scale, and probably will not in very near future. After more than half-a-year of article writing and lecture preparing, I must admit I felt exhausted. Of course, it was a huge honour to both me and our team to be invited to deliver this plenary in the 15th International symposium of the IAFSS in La Rochelle, France, this June. Big thanks to my co-author Soroush Rashidzadeh for your amazing contributions!

The title of the lecture was Thermal Radiation – From Science to Engineering. I started with an overview of methods in solving the radiation transport equation as well as radiative properties of gases. But the main focus was in the challenges arising from the use of grey assumption, and the operating principle of the modern non-gray models that tackle the non-greyness through spectral re-ordering.

A recording of the lecture can be found from the IAFSS Youtube channel, and the full article from Fire Safety Journal.

Many colleagues have asked if they could use some of the presentation material. So I decided to share the PowerPoint file and the script for creating the Line-by-line (LBL) animation through GitHub. I used AI to generate the script, but was amazed how quickly I was able to perform real, physics based LBL using a true HITEMP API.

To celebrate the long process of writing the article and preparing the presentation, we visited Serlachius Art Museum in Mänttä, Finland with my wife. There we saw something very special: radiation -relevant contemporary art. Anish Kapoor’s Non-object black radiates but doesn’t reflect! In these sculptures, Kapoor has used Vantablack, a carbon nanotube -based commercial coating, which has super low reflectance at visible wavelenghts. (In their website, the manufacturing company claims absorption characteristics are similar all the way to far IR.) It was an amazing experience to watch something you don’t see! These objects have shapes, but you cannot see them until you watch from some particular direction, e.g. from the side.

Posted by Simo Hostikka

Since about two years, part of our team has been participating in planning and kick-off of the IAFSS Measurement and Computation of Fire Phenomena -working group on radiative heat transfer. This sub-broup was officially established in the third MaCFP meeting in Tshukuba, 2023.

The first activity of this group has been to prepare two benchmark simulation datasets using Particle Monte Carlo – Line-by-line modelling. Leading figures here have been Chandan Paul (now at NIST) and Prof Somesh Roy (Marquette Uni). I add below a snapshot of our recent poster in Combustion Institute meeting, presented by prof Fabian Brännström (Uni Wuppertal). These benchmark datasets were very recently published in Journal of Quantitative Spectroscopy and Radiative Transfer.

The idea of generating numerical benchmarks came from the observation that it is very difficult to perform detailed radiation measurements in fires or flames of relevant size. Also, when modelling the radiation phenomena, all the uncertainties of boundary conditions, fluid flow, turbulence, combustion, etc., will propagate to the radiation predictions and make it difficult to isolate the uncertainties that originate from radiation models themselves. By carrying out PMC-LBL and classical RTE solutions that are based on exactly the same scalar fields (temperature, concentrations), we should be able to isolate the sources of error.

Currently, we try use these datasets for validating non-gray gas phase radiation models for FDS. This work is carried out by Soroush Rashidzadeh in his doctoral thesis project. The FDS implementation will build on the analytical model comparison (also JQSRT), and the two-zone Turbulence-Radiation Interaction model, we published with Randy McDermott of NIST.

Posted by Simo Hostikka

Fire-stops are an essential component of buildings’ fire resistance. They are used for closing gaps between compartment boundary elements and as seals for cable and pipe penetrations. Many modern fire stop materials are based on polymeric materials, and for a basic fire protection engineer, it is difficult to understand why and how they can work. Why don’t they just burn away?

Also, building are designed for tens of years use, and the fire stops should be effective throughout the whole use period. Ageing of polymeric materials has been a hot topic of nuclear safety for many years, but there is little information on how the fire-stops perform when they get old.

If you are interested in characterizing commercial fire-stops, studying their ageing performance, and developing numerical models for their performance assessment, this could be your opportunity to get into academia. If you have a MSc degree and relevant skills, go ahead, read more and apply over here.

Posted by Simo Hostikka

Farid Alinejad defended his thesis in May 12th, 2023. The title of his thesis is “Modeling in-depth transfer of thermal
radiation in non-gray condensed materials”. Opponent was Prof Frédéric André from INSA, Lyon (now Univ Lille). Defense was successful and Farid has now graduated, and is already making career in research. Congratulations!

Farid’s work was extensive. The thesis was based on five published papers:

1. Alinejad, F., Bordbar, H., & Hostikka, S. (2020). Development of full spectrum correlated k-model for spectral radiation penetration within liquid fuels. International Journal of Heat and Mass Transfer, 158, 119990. https://doi.org/10.1016/j.ijheatmasstransfer.2020.119990
2. Alinejad, F., Bordbar, H., & Hostikka, S. (2021). The ordinate weighting method for solving radiative heat transfer through a Fresnel interface. Journal of Quantitative Spectroscopy and Radiative Transfer, 270, 107685 https://doi.org/10.1016/j.jqsrt.2021.107685
3. Alinejad, F., Bordbar, H., & Hostikka, S. (2021). Improving the modeling of spectral radiation penetration into the condensed materials with the separated full spectrum correlated-k method. International Journal of Heat and Mass Transfer, 176, 121448. https://doi.org/10.1016/j.ijheatmasstransfer.2021.121448
4. Alinejad, F., Bordbar, H., Makowska, M., & Hostikka, S. (2022). Spectroscopic determination of the optical constants and radiative properties of black PMMA for pyrolysis modeling. International Journal of Thermal Sciences, 176, 107501. https://doi.org/10.1016/j.ijthermalsci.2022.107501
5. Alinejad, F., Bordbar, H., & Hostikka, S. (2022). On the importance and modeling of in-depth spectral radiation absorption in the flammability analyses of black PMMA. Fire Safety Journal, 103706. https://doi.org/10.1016/j.firesaf.2022.103706

First two dealt with fundamental methodological development for thermal radiation modelling. The third and fourth were focus on the material modelling using non-gray methods, and the fifth combined all these methods into pyrolysis modelling in fire engineering.

Prof André’s visit was an intersting opportunity for us at Aalto to learn about the forefront of radiation modelling. We look forward in new collaboration in this field.

Posted by Simo Hostikka

Rahul has reach a point at his research path at Aalto University, when it is time to say Goodbye! He started in Aalso’s FSE group as a MSc thesis worker in PAHAHUPA -project. From that project, he received two journal articles:

1. Kallada Janardhan, R., Hostikka, S. Experiments and numerical simulations of pressure effects in apartment fires. Fire Technology, 53(3):1353-1377. 2017. http://doi.org/10.1007/s10694-016-0641-z
2. Hostikka, S., Kallada Janardhan, R., Riaz, U., Sikanen, T. Fire-induced pressure and smoke spreading in mechanically ventilated buildings with air-tight envelopes. Fire Safety Journal, 91:380-388. 2017. doi:10.1016/j.firesaf.2017.04.006

Rahul’s doctoral thesis is titled “Understanding fire spread, its influence on structures and fire intervention tactics through computational methods”. You can find the thesis from https://aaltodoc.aalto.fi/handle/123456789/114663

The thesis is built on the basis of four collaborative research papers. First two developed a computational affordable (coarse mesh) CFD method for modelling fire spread on wood. Third investigated the effect of spreading fire on structural response through CFD-FEA coupling, and the fourth one introduced the aspect of fire intervention by developing a CFD model for large fire brigade water sprays and a means to consider cooling in the CFD-FEA coupling.

1. Kallada Janardhan, R., Hostikka, S. Predictive Computational Fluid Dynamics Simulation of Fire Spread on Wood Cribs. Fire Technology, 55:2245-2268. 2019.  http://doi.org/10.1007/s10694-019-00855-3
2. Kallada Janardhan, R., Hostikka, S. When is the fire spreading and when it travels? – Numerical simulations of compartments with wood crib fire loads. Fire Safety Journal, 126: 103485. 2021. https://doi.org/10.1016/j.firesaf.2021.103485
3. Kallada Janardhan, R., Shakil, S., Lu, W., Hostikka, S., Puttonen, J., Coupled CFD-FE analysis of a long-span truss beam exposed to spreading fires. Engineering Structures, 259, 114150, 2022. https://doi.org/10.1016/j.engstruct.2022.114150
4. Kallada Janardhan, R., Shakil, S., Hassinen, M., Lu, W., Puttonen, J., Hostikka, S. Impact of Firefighting Sprays on the Fire Performance of Structural Steel Members. Fire Technology, 2022. https://doi.org/10.1007/s10694-022-01257-8

Rahul’s defense was organized in June 15th, 2022. Opponent was Prof Wojciech Węgrzyński of Institute Techniki Budowlanej, Poland. The examination lasted for about two hours and covered the entire thesis work. Here is a group photo after the defense, with opponent, candidate, and custos wearing black.

As the last project, while waiting for the reviews of his latest journal, Rahul participated in the measurements of LIESIPALO-project.

Posted by Simo Hostikka

We are part of the Nordic Fire and Safety Network!

The Nordic Fire and Safety Network is a consortium consisting of the Nordic universities and research institutes dealing with risk and fire safety. The network is organized by the Technical University of Denmark in collaboration with RISE (Research Institutes of Sweden), Norwegian University of Science and Technology, Lund University, Aalto University, Luleå University, University of Stavanger, Western Norway University of Applied Sciences and Iceland University as well as VTT Technical Research Centre of Finland Ltd and Danish Institute of Fire and Security Technology.

Main activities:

• Seminars on research and education
• Nordic Fire and Safety Days
• PhD student workshops and summer schools
• Researcher exchange

In fall 2021, Aalto hosted a (online) PhD student workshop on the theme of sustainability of research. Next workshop is planned for August 2022.

Posted by Simo Hostikka

Our publicly funded project on the multiphysics simulation of stone-wool fire resistance is now ending. In this project, we studied the thermal behaviour of stone wool and developed simulation models to extend the standard test results. The project was made in collaboration with Owens Corning Paroc who provided experimental test data from 30 different stone wool samples.

The work was published in Fire Technology.

The work was funded by Palosuojelurahasto.

The main conclusions were

• Stone wool, as other non-combustible, A1 class insulation materias contain varying amounts of organic materials that react with oxygen during fire, and produce heat that increases wool temperature even tens of degrees.
• Temperature increase is highest in stone wools with high organic content, but the amount of organic content alone does not explain the whole phenomenon. It is necessary to consider the transport of oxygen too.
• The processes can be best simulated with models that include both heat conduciton, mass transfer, and heterogenous reactions.
• Closing the stone wool between non-permeable linings, like steel sheets in sandwich elements, will prevent oxygen diffusion into the wool, and reduce the cold-side temperatures.

 

Posted by Simo Hostikka

Simo posted at LinkedIn about the calculation of infection risk and aerosol concentrations in closed spaces with ventilation. This was a result of consultation with public transport -related actors in Finland. In the end of the post, there will be links to a GitHub space with matlab-functions.

 

 

Posted by Simo Hostikka