The Science of Suppression FIRESEAT symposium

On November 9th, 2011 the students from the International Masters of Science in Fire Safety Engineering (IMFSE) studying in Edinburgh University were invited to attend the 5th FIRESEAT symposium "The Science of Suppression". During this conference, attended by ~85 people, we saw eight different speakers from varying parts of the world discussing topics focus around fire suppression.

The first speaker we had the privilege of seeing was Ronald Alpert. As the Alpert Correlations were among the topics covered in our Fire Dynamics course, we were all excited to hear him speak. Alpert explained how he designed his correlations and revisited them with new experiments. He eagerly stressed his excitement for someone to advance his correlations past the current level in which they are.

The next speaker was Yibing Xin of FM Global. Sprinkler technology was the topic discussed. FM Global is working on being able to affectively model how sprinkler systems work during suppression. By doing so, they are creating a new modeling tool, FireFOAM. This would be a very useful tool because of the expensive costs of having full-scale burns. We recognize the challenges faced in order to create a program such as this, although there is no doubt that it would be a great use to the Fire Protection Community.

Andre Marshall form the University of Maryland was the third speaker of FireSeat. The research Marshall is conducting also focuses around sprinklers. In contrast to Yibing, his research involves quantitatively breaking down the spray pattern of a sprinkler head and analyzing it. The techniques being used by Marshall are nothing short of impressive.

FireSeat at this point made a turn toward the use of water mist sprinkler systems. Louise Jackman of LPCB discussed some research she was conducting. This involved using mist systems in different setting with different variables. All we could conclude from this was that mist systems are temperamental, in which the system requires just the right variables to effectively work.

The next speaker was Stefan Kratzmeir of IFAB. He discussed his research involving the use of water mist systems in tunnels, hiting mist could be effective in mitigating a fire. Our concern with this topic was the interaction between the mist and the ventilation. We felt this concern was not addressed.

The next research area discussed was the use of cryogenic suppression, presented by MichaelDelichatsios of the University of Ulster. He explained the used of cryogenic material (mainly liquid nitrogen) to extinguish pool fires and wood crib fires. Although the method was effective, the delivering of the agent to the seat of the fire seems to remain the issue in which water and foam systems still have over such a suppression agent.

Suppression in tunnels again arose with the next speaker, Elizabeth Blanchard. Her modelling results of fire suppression inside a medium size tunnel seemed to be more accurate than previous studies. But the question already began to loom among our students concerning the interaction between the mist delivered and ventilation. Our concern was again not addressed, despite the effectiveness of the mist system to mitigate fire and enhance visibility, we felt more research should be performed to address the issue.

The final speaker of the 2011 FireSeat was Stefano Chiti of COWI. This research involved using hypoxic air for fire suppression and prevention. This would basically displace oxygen in the combustion process making combustion slow or near impossible to occur. This is a good research area, especially since Halon is no longer being used. We can see the use of this being great as long as it is ensured not to effect human life.

FireSeat was a great experience. It showed suppression research has many different areas that will improve the suppression actions of the Fire Protection Community in the future.

by Joshua Reichert and Oriol Rios, 2011 IMFSE students

Fire on Earth at the 2011 European Geosciences Union

Dear Researchers interested in Fire and the Earth System,

We very much hope that you will join us at European Geosciences Union (EGU) General Assembly 2012 in Vienna this April by submitting an abstract to our session "Understanding Fire Phenomena in the Earth System Using Interdisciplinary Approaches". The session aims to bring together all disciplines within fire science toward increasing scientific understanding of the impact of fires on the Earth system. The session will position contributors into four key fire research themes:

• Fire Behaviour
• Fire and the Biosphere
• Fire and Earth’s Past
• Fire and the Earth System

These groupings are designed to enhance interaction between the communities of fire safety science and engineering, wildfire ecology, palaeofire and Earth system science enabling insight to be gained into the influence of fire on our planet. More importantly we hope that the session will enhance interaction between all our communities.

The deadline for your abstract submission is 17th January 2012.

EGU has a number of exciting fire based sessions this year making it a must for all of us interested in fire science.

We hope to see you all at Vienna in April.

Best wishes,

Claire Belcher and Guillermo Rein (session organizers)

2010 Impact Factors for fire related journals

The Journal Citation Reports has released the impact factors for 2010. The impact factor, one of the measures available to rank journals, is the frequency with which the "average article" in a journal has been cited in the previous two years. It is calculated dividing the number of citations to papers published in the previous two years by the total number of items published during the same period. In order and for fire related journals, these are:

#1 Progress in Energy and Combustion Science 10.36 (was 12.44 in 2009)
#2 Journal of Hazardous Materials 3.72 (was 4.14 in 2009)
#3 Combustion and Flame 2.747 (was 2.92  in 2009)
#4 International Journal of Wildland Fire 2.21 (was 1.90 in 2009)
#5 Building and Environment 2.13 (was 1.80 in 2009)
#6 Proceedings of the Combustion Institute 1.79 (was 3.51 in 2009)
#7 Engineering Structures 1.36 (was 1.26 in 2009)
#8 Experimental Thermal and Fluid Science 1.27 (was 1.23  in 2009)
#9 Combustion Science and Technology 1.11 (was 1.14 in 2009)
#10 Fire Safety Journal 1.02 (was 1.26 in 2009)
#11 Fire and Materials 0.96 (was 1.20 in 2009)
#12 Journal of Structural Engineering 0.83 (was 0.93 in 2009)
#13 Fire Technology 0.36 (was 0.37 in 2009)
#14 Journal of Fire Protection Engineering 0.15 (was 0.30 in 2009)

Clarification (derived from the wikipedia):
The 2010 impact factor of a given journal is equal to A/B. Where A is the number of times articles published in 2008 and 2009 were cited during 2010, and B is the total number of papers published by that journal in 2008 and 2009.

NOTE: Support your favorite journals by reading (and citing) them often

2011 Lloyd’s Prize to fire research

Congratulations to Dr Angus Law and co-authors for winning the 2011 Lloyd’s Science of Risk Prize in the Biological/Technological category for their paper on travelling fires for structural design. Dr Law graduated in 2010 with a PhD in Fire Safety Engineering from the University of Edinburgh and now works at Arup. The Science of Risk Prize was launched by Lloyd’s to stimulate cutting edge research into the latest emerging risks facing businesses.

 Design for infrastructure protection

The winning paper  is "The Influence of Travelling Fires on a Concrete Frame" (published in Engineering Structures 33), led by Dr Law and co-authored by Dr Stern-Gottfried, Dr Gillie and Dr Rein. The work argues that the trend towards open plan offices has changed the types of fire likely to occur in modern buildings. It uses science to look at ways to improve engineering guidelines and building design, reduce the risk of travelling fires, and help insurers better quantify and model fire risk. The presentation given by Dr Law at the award's ceremony built on the concepts of acceptable risk and the margin of error of design methods in the contextt of the engineering duty to use the world’s limited resources as efficiently as possible (see presentation here). The work was founded by BRE Trust and Arup.

Best runner-up

The best runner-up in the same category was our graduate Dr Sung-han Koo for his paper "Sensor-steered fire simulation" (published in Fire Safety Journal and co-authored by Dr J Fraser-Mitchell and Dr S Welch)

2010 Awards

This is the second time that Edinburgh recieves the award. Last year Dr Francesco Colella won the 2010 (inaugural) prize in Technology for the paper "A Novel Multiscale Methodology for Simulating Tunnel Ventilation Flows During Fires". And Dr Wolfram Jahn (in Technology) and Dr Claire Belcher (in Natural Hazards) were short-listed within the top five submissions.

Related links:

• The Science of Risk - Lloyd’s Research Prize
• Press release from BRE "Centre of Excellence Student Claims Top Prize"
• The University’s BRE Centre for Fire Safety Engineering
• 2010 Lloyd’s Science of Risk Prize goes to Fire Technology

Letter to the Editor of Scientific American

(Email sent on Thur 15 Sep 2011 to editors@sciam.com) 

Dear Editor of Scientific American,

Your September issue included the piece "Castles in the Air" by Mark Lamster where the failed prophecy that the attacks of 9/11 were to end the age of the skyscraper is discussed. 

The article highlights that 2011 will be the single greatest year for the construction of tall buildings in history. That China is leading the skyscraper boom, yet their engineering design is dominated by American firms.

The article discusses design issues on evacuation. But the World Trade Center was designed to evacuate rapidly, and so both towers WTC1 and 2 did below the impact floors on 9/11. WTC7 was also evacuated in time.

The article also discusses design issues on aircraft impact. But the World Trade Center was designed to withstand the impact of a large aircraft, and so both towers WTC1 and 2 did on 9/11. They collapsed because of fire. WTC7 was not hit by an aircraft, but collapsed due to fire as well. 

The article goes to imply that the design of tall buildings for protection against terrorist attacks is mostly about aircraft impact and evacuation. It does not discuses fire. But WTC 1, 2 and 7 collapsed because of fire. So they only issue that is not addressed in the article is the one that brought World Trade Center down, and the one where design advances over the past decade have been most marginal. 

This is a thin favour to fire engineering and to the safety of tall buildings.

Sincerely,


-- 
 *Dr Guillermo Rein*
Senior Lecturer in Mechanical Engineering
University of Edinburgh
http://www.eng.ed.ac.uk/~grein

"so easy it seemed, Once found, which yet unfounded most would have
thought, Impossible!" J Milton  


UPDATE Sept 2011: This letter was followed by two more from Dr Bisby and Hilditch

UPDATE Dec 2011: The letter of Dr Bisby has been published in the December 2011 issue of Scientific American.

FIRESEAT: The science of suppression

Join us in Edinburgh on 9th November this year for a one day symposium on 'The Science of Suppression'. Online registration now open. Click the image above or visit www.fireseat.org for more information.

Dr Belcher takes Earth System Science position at University of Exeter

Congratulation to Dr Claire Belcher who has got an academic position at the University of Exeter as a Senior Lecturer in Earth System Science.

She will join the College of Life and Environmental Sciences there in January 2012 to continue research on the flammable history of the Earth and plans to maintain strong links with us.

She is sorry to be leaving the FireLab but is looking forward to living in the warmer south and setting up her own research group.

NOTE: Yes, you are right. Claire has promoted directly from Research Fellow to Senior Lecturer without resting at the Lecturership level. That I see as the take off of a stellar career indeed.

PhD defense of Jamie Stern-Gottfried on Travelling Fires for Structural Design

Dear All,

I’m very happy to convey the news that Jamie Stern-Gottfried has successfully defended (with flying colours) his PhD viva, “Travelling Fires for Structural Design (pdf)” this morning in Manchester.

The viva was instructive and educational for all (candidate, supervisor (Guillermo Rein), internal examiner (Luke Bisby), and even external examiner (Colin Bailey)), and Jamie has only very minor corrections to make before he can insist (as I'm sure he will!) on being called Doctor.

In the words of Prof Bailey, all of the questions were “extremely well answered” and the thesis was beautifully defended.

Congratulations to Jamie (and to Guillermo) for this novel and important piece of work!! I can only hope that Jamie’s penchant for collaboration with structural engineers continues in the future...

Luke Bisby
Internal Examiner

(sent on Fri, 15 Jul 2011)

Call for papers: Fire Technology special issue on WTC Collapse

Fire Technology, the journal of the National Fire Protection Association published by Springer, is preparing an issue on the 2001 fire and collapse of World Trade Center.

The purpose is to collect research, forensic and engineering output of the highest scholarly standards synthesized in the 10 years passed since the event.

Multidisciplinary and international contributions are especially encouraged. Topics of interests include: WTC 1, 2, 5 and 7, the crash, fires, structural response, collapse, forensic conclusions, experiments, modelling, Fire and Rescue intervention, human behaviour, building design, post-collapse fires and recovery, previous attacks on WTC and related subjects.

Submissions will be accepted until 11th Nov 2011 at: http://fire.edmgr.com (choose article type "World Trace Center") .

The call for papers flyer can do downloaded here. Please spread the word, we are looking for a wide range of high quality submissions.

For further information, contact the Associate Editor of this special issue: G.Rein@ed.ac.uk, Dr Guillermo Rein, The University of Edinburgh.

A New York City fireman calls for 10 more rescue workers to make their way into the rubble of the World Trade Center. Photo form Wikipedia, United States Navy ID 010914-N-3995K-01

Rory Hadden PhD defence

Dear all

It is my pleasure to inform you that Rory Hadden has successfully defended his PhD thesis in the viva exam today, subject to minor editorial corrections.  His studies were supervised by Guillermo Rein and the thesis title was:

Smouldering and self-sustaining reactions in solids: an experimental approach 

The external examiner was Dr.-Ing. Martin Schmidt, Head of working group on Flammable Bulk Materials and Dusts, Solid Fuels at BAM (Federal Institute for Materials Research and Testing); I was the internal.

Rory had done a great job exploring the diverse topics of smouldering combustion, from fertiliser fires and fire brand ignitions to the pervasive problems of (unwanted) underground coal and peat fires.  So there was no need to haul him over the coals ;)

Well done Rory!

Stephen

-------------------------------------------------------------
Stephen Welch

Lecturer in Computational Methods for Fire Safety Engineering
SAFE MSc Course Director
IMFSE Director of Studies

PhD funding on subsurface fires. Earth and Natural Sciences

A PhD studentship to study peat fires between University College Dublin and University of Edinburgh is available to a student of any nationality. We are most interested in engineers, physicists and chemists with a background on thermal sciences, some experience in laboratory work and an interest on Earth sciences. See below a brief description. For information and application, see PhD Programme in Earth and Natural Sciences at UCS.

Project BIO 3: Characterising the dynamics and environmental impact of subsurface
peat fires by controlled experiments

Principal Investigator: Dr Jon Yearsley (UCD) – jon.yearsley@ucd.ie
Collaborators: Claire Belcher (University of Edinburg); Guillermo Rein (University of Edinburg)

Fire is an increasing global threat to the carbon store and ecosystem services provided by peatlands (they contain 1/3 of terrestrial carbon). Peatland wildfires are extreme events that are becoming more frequent both in Ireland and internationally. Smouldering peat produces 5‐40% of annual global carbon emissions, but these are presently not accounted for by the IPCC7. They threaten the environment (e.g. habitat destruction and greenhouse gas emissions) and human health (e.g. air quality), but our understanding of these smouldering fires is poor compared to flaming fires. The core of the project will study sub‐surface peatland fire behaviour by performing experimental peat burns for a range environmental conditions. The student will develop the experimental protocol at the Centre for Fire Safety Engineering (University of Edinburgh) and then installed at UCD for the majority of the experimental manipulations. This project combines fire dynamics and Earth systems research and builds upon an existing collaboration between UCD and University of Edinburgh. The work has relevance to climate change mitigation/adaptation, managing peatland carbon stores against the risk of sub‐surface fires and the fundamental science of smouldering fire. We are looking for an outstanding student with interest in undertaking experimental research on the interface between fire dynamics, Earth systems and ecological modelling.
There is one PhD Studentship associated with this Project and will be based at UCD

The Twin Towers: 10 years – 10 Lessons on Sustainable Infrastructure

On Monday 14 March 2011, Prof Jose Torero (University of Edinburgh) delivered the public lecture:

The Twin Towers: 10 years – 10 Lessons on Sustainable Infrastructure

Joint event of The Royal Society of Edinburgh and The Royal Academy of Engineering.

The collapse of the World Trade Center towers represents one of the most dramatic failures of modern structural engineering. One of the most exhaustive and expensive failure analyses in history was conducted in the midst of speculation, controversy and conspiracy theories. In parallel, the world has seen an extraordinary evolution of the super-tall building. Seven of the ten tallest buildings in the world have been built after 9/11. These not only include the tallest four, but eight of these buildings are outside the USA. Furthermore, a strong drive towards sustainability has driven tall building design to levels of innovation never seen before. This presentation will extract, from a decade of questioning and innovation, ten lessons on what is sustainable infrastructure.

A summary of the lecture and the 10 lessons can be read here

Seminars on Flame generated species, and on Amazonian Wildland fires

The Fire Group is hosting 2 seminars next week - see details below

ALL WELCOME

--
Tuesday 8 March, at 1pm
Sanderson Classroom 3
Pizza at 12.45 in Sanderson Foyer

Speaker: Dr Johannes Kiefer, Lecturer in Chemical Engineering, University of Aberdeen

Innovative approaches for the detection of flame generated species

The detection of combustion generated species is an important task from many viewpoints. Firstly, it is essential in the field of combustion research where a major aim is to obtain information about the distribution of the fuel and oxidiser, the products, as well as transient intermediates with high spatial and temporal resolution. This allows the complex phenomena of combustion chemistry, turbulence, heat and mass transfer, and their interactions with each other to be studied. Secondly, combustion species detection is important for environmental and safety reasons, in particular in view of toxic and corrosive products that can cause severe problems when human beings or structures are exposed to them. The presentation will give an overview of recent developments in the field of optical combustion diagnostics using innovative light sources. This includes the use of novel ultraviolet light emitting diodes (LEDs) for the quantitative detection of sulphur dioxide at trace level, and the use of alexandrite lasers, which are actually well known for applications in cosmetic surgery, for imaging of flame radicals.

-
Friday 11 March, at 1pm
AGB Seminar Room

Speaker: Dr Saulo Freitas, INPE Brazil, Centro de Previsão de Tempo e Estudos Climáticos

Wildland fires in Amazonia as seen from the atmosphere

Biomass burning in Amazonia recurrently releases large amounts of trace gases and aerosol particles to the atmosphere. The consequent change from low to very high atmospheric concentrations of oxidants and aerosols therefore affects the radiative, cloud microphysical and chemical properties of the atmosphere over Amazonia. This seminar aims to summarize current studies and numerical regional modeling at INPE of the biomass burning process and its impacts on weather, climate, and air quality. We will also describe the model developments associated with the estimation of biomass burning emissions, the plume rise mechanism and the fully coupled atmospheric chemistry transport model developed to study and forecast smoke aerosol and trace gas concentrations, weather and air quality.

How Uncertainty Transforms the Way we Quantify Fire

Posted in the name of Prof Jose Torero.
(related to the previous blog entry "Study or Gamble, but not both - 2nd annual Christmas tree fire test")



It is common practise to use experimental data for many purposes in the analysis of Fire Safety. It can be used as direct input (HRR, flame spread rates, ignition times, etc.) to models (analytical, semi empirical and CFD) as well as to obtain parameters that then can be used as input to other more fundamental models (heat of combustion, thermal properties, etc.). In many cases, due to the complexity of the tests, we rely of single data points to infer the values that we need. We can conduct a detailed analysis of the data and provide output values. In this particular case, the output values were the pHRR and the burn time of the tree. If I was to use this data for modelling, both parameters will be of critical importance and I could define a Q_dot=alpha x t^2 fire on the basis of both parameters. Furthermore, I could divide the HRR curve by the burning rate and obtain a heat of combustion that together with a flame spread model I could convert into another form of Q_dot. I could even use this data as part of a fundamental model that will attempt to predict all processes involved. Much of the research work we do tries to do two things, develop better models and try to make best use of the data we have. Thus this test is a fun example of what we are all about!

So, given the interest that this particular test has created I thought that it will be important to do a little exercise of uncertainty, not to question the winner, or to question the methodology used in defining this winner, simply to establish how important it is to look at these tests with caution and how difficult it is to use them in a manner that is truly representative of the event we are trying to describe via our engineering techniques. Furthermore, it is important to do this analysis to establish one of the key values of apriori estimations coupled with aposteriori explanations.

Apriori estimations have the distinct value of providing predictions that are only biased by the user’s knowledge or experience and not by the knowledge inferred through the observation of the test. Aposteriori estimations always carry the bias associated to having the knowledge of the results of the test. The aposteriori analysis of the apriori predictions reveals the effectiveness of the thought process associated to the apriori predictions. This analysis is extremely valuable in the sense that it can allow to separate the logic that is “user robust” from that that is purely a “guess.” It is also important because it allows establishing which of these “user robust” criteria have large experimental variability. Finally, it allows to identify common errors that can lead you to a “bad guess” but most important to a “good guess.” “User robust” logic with known “variability” is what we want to use to interpret test data and extract this information to introduce into our Fire Safety calculations.

I will do an aposteriori analysis of my estimates not to over-emphasize/or counteract the ridicule of being among the furthest away from the answer or to incontestably establish how my brain seems to have deteriorated with years doing fire research. The objective of this analysis is to encourage you to retrospect on how you achieve your estimate, post it, and let’s see what are the “user robust” criteria, which criteria is not robust, what were purely “guesses” and of these which ones are good or bad.

I know I am taking the risk of taking the joy out of a fun event, but given my role as an educator I find myself compelled to do this. The effort put on the tests and Guillermo’s fantastic statistical analysis encouraged me to do this. In any case, if you do not feel it is important, you will not participate and that is the end of the story!

900 kW and 20 seconds – How did I get there?

The way I reached my estimates, which I tried to qualify, but was told I could not (fair enough), was based on my experience of similar data published in the literature and the previous test conducted in Edinburgh.
When estimating the pHRR I made the following assumptions:

• The variability between tress in the literature was small.
• The pHRR was dominated by upward flame spread (VS) and time to burn out (tBO) of the leaves. Lateral flame spread is negligible compared to upward flame spread of a fuel of such low density, thus the effect of radial spread will happen after the pHRR.
• The base of the fuel burning (A) will be dominated by buoyancy not lateral spread, thus it should be the same for all tests.
• The tBO is very small and the base of the tree tends to have a higher density than the top, thus the pHRR will be generally attained before the flames reach the top of the tree.
• The HRR (given that this is a low density porous medium) will be proportional to the burning volume, so given a constant value of “A” it will be proportional to the height, thus to H=VS.t_b.
• The available data generally estimates a pHRR that ranges between 900 kW and 1100 kW.

So, given that the real height of the tree should not matter, then the pHRR should be similar to that of the literature. Because the tree was small, it was not so dry and it did not seem that dense I decided to opt for the lower bound value and estimate 900 kW.

Now, that being said, generally, literature values tend to be corrected by the time delay of the calorimeter. Our calorimeter has a time delay of about 10 seconds. What does that mean? Basically, it means that oxygen consumption measurements lag by 10 seconds the mass burning rate measurements. This generally makes no difference for events where things do not change within that period. If the event time scale is of the same order of magnitude of the time delay, then the measured value is somewhere between the measurement and that 10 seconds later. So, if I was to take the HRR curve measured by the calorimeter, then the value will be somewhere between what was measured 697 +/- 25 kW and 1000 kW.

An important lesson to learn is that the pHRR of a fast event (actually, even a slow event, but for different reasons) is a very difficult quantity to estimate precisely, thus the +/-25 kW stated as the error is truly only the direct measurement error. The true error will have to include the variability associated to the burn out time, the buoyantly driven upward spread, the global density and the comprehensive experimental error which is a parameter that is relevant in this case because the times are so short. So, any estimates within +/- 200 kW will probably have exactly the same value if the variable used is the pHRR. Thus 11/28 of you truly guessed the same answer.

If a different variable, such as the average HRR, or the Heat of Combustion was to be used as the “estimate,” then once all corrections due to time delay were made, would have probably delivered a smaller error bar.

The second variable to be estimated was the burning time. My estimate was 20 seconds and was based on a simple calculation of a typical upward flame spread rate of 10 cm a second. This had nothing to do with trees but with a fuel I know better (polyurethane foam). I estimated that the global value of “krhoC” is dominated by the density and I assumed that the density was more or less the same for both fuels. Thus I took that number. The tree was about 1.5 m, this gave about 15 seconds, time to burnout is so short that once the flame spread to the top, I could assume the fire was over.

Now, here is where I tried (unsuccessfully) to introduce a qualifier, I could not engage to estimate the initiation time (from the moment of ignition to the moment when the fire truly takes off). Furthermore, after the pHRR, what is left is lateral spread, then the branches and finally the trunk. The trunk will extinguish as soon as the branches die (bulk wood does not burn unless assisted!), but the lateral spread (being dominated by the shape of the tree) and the branches (being dominated by their individual shape and size) are impossible to predict. So at the end I gave up and simply estimated the time that it will take to achieve the pHRR from the moment the fire truly takes off. I reluctantly added a 5 second buffer for the slow initiation. While not a good estimate for what I was being asked, there is something to be said for the accuracy of the estimate! From the HRR curve we can establish that the primary burning will be somewhere between 10-20 sec (considering the instrument delay).

Now, what have I learnt, buoyancy is such a strong driving force that the estimate of the upward flame spread is a very robust one. The estimate of total burning time is one that carries a massive error bar, thus I will be reluctant to dismiss any of your estimates. From my perspective 28/28 gave estimates that I will consider within the expected error bars. Needless to say, last year’s Christmas tree was the proof to this point; the initial time could have been infinite if I did not decide to push the candle towards the denser part of the tree!

A final point, did I think of all of this in the 2 minutes that passed between the moment I learnt of the bet and the moment I provided my estimates? Obviously not! Most of this knowledge resides within your experience, and the estimate is an “educated guess.” Nevertheless, for the estimate to be adequate we need to carefully assess the question being asked (which I unfortunately decided to ignore) and the question needs to be posed correctly (meaning that what is being asked needs to have error bars that are smaller than the discrimination we are seeking). Otherwise, our guess will not be educated, nor it will be an estimate, it will just be a guess. If the error bars are small your chances of being the closest answer are very small (the educated estimate will have a much greater chance), but if the error bars are large you have as much of a chance to get it right as the most educated of estimates.

So citing Guillermo Rein: “while many stories can be told aposteriori,” and 3 hours of rationalizing my estimates can lead to this story, the stories need to be told and the discussion needs to follow. It is within the aposteriori 3 hours of introspection that I have truly managed to gain some insight into what happened not within the 2 minutes it took me to “guess.”

Congratulations to the winner!

Prof Jose Torero.

Study or Gamble, but not both - 2nd annual Christmas tree fire test

An esteemed colleague had generously donated a Christmas tree to the scientific cause for the 2nd annual Christmas tree fire test. It had been used in the living room during the winter celebrations.

The tree was a Nordmann Fir of conical shape, 1.5 m tall and 0.9 m diameter at the bottom. It weighted 4.74 kg and was in dry conditions (measured in the oven at ~8% moisture content in dry base) after having spent one month not watered inside a warm living room.

Before conducting the experiment, fire experts were asked to bet on the peak heat release rate (pHRR) and the burning time (t_b). We recorded 28 guesses (£1 was collected per guess). A person with no research experience and no previous knowledge on fire dynamics (an international lawyer) was asked to provide a guess and act as control. NOTE: This required explaining the concept of HRR in layman terms, after which the control quantified the pHRR in terms of the equivalent number of burning matches.

Significant spread was recorded in the guesses. pHHR guesses ranged from 400 and 2300 kW, with average at 1173 kW. Guesses for t_b ranged from 15 to 377 s, with an average of 120 s. Two people provided guesses for pHRR but not for t_b, so they were assigned the average t_b value from the other participants.

Figure 1. Sequence of images, from left to right: The first day (early December 2010) when it was brought to the living room. Just seconds before ignition when the tree was inside the medium scale calorimeter. Fire spread over the tree about 40 s after ignition. Remains left after the test.

The tree was ignited putting a small household candle next to the tree trunk at 1/3 of the height from the base. The HRR was measured using oxygen consumption calorimetry (corrected for CO and CO2 production). Figure 2 shows the HRR as a function of time. The growth of the fire is very fast, reaching a peak near 700 kW, 45 s after candle ignition.  The decay is also fast, and reduces the fire to 50 kW 60 s after the peak. The peak value (pHRR) was 697 kW ± 25 kW. And the burning time t_b was 146 s ± 24 s. This was measured by visual observation using the video of the test and defined as the period going from first observed ignition of a tree element (between 0 and 24 s after candle ignition) to the end of significant flaming (between 146 s and 170 s).

Figure 2. Evolution of the HRR (power) as a function of time measured by oxygen consumption calorimetry.The ranges of observed times for the ignition of first tree element and end of flaming are indicated.

A short video of the test can be seen below (NOTE: it starts 30 s after ignition and lasts for 55 s):

Measurements and guesses are plotted in Figure 3. There was only one guess falling within the measured result range. This person won the bet. For the quantification of how close a guess was to the measurements, the Euclidean distance was calculated, nondimensionalizing each guess by the measurement. The resulting average distance is 0.97, with minimum 0.1 and maximum 2.12. The control was at a distance of 0.26, well below the average and closer to the result than 89% of the participants.

Figure 3. Scatter plot of the guesses for the Peak HRR and the burning time. Measurements and experimental uncertainty are in blue. Histograms of guesses for each quantity are included.

The participants were grouped in three sets: Academics, Postdocs and Students. The years each participant has been researching fire was estimated and plotted against the distance of each guess (see Figure 4). There is a positive correlation of distance with experience. Students and postdocs show a similar large slope, but Academics are a distinct group from the rest and have a smaller slope.

Figure 4. Non-dimensional Euclidean distance from guess to measurements vs. years in fire research of each participants. Blue line is the trend of the Student and Postdoc populations.

Upon seeing this data, one could conclude that the longer you stay in research, the less you earn. And, study or gamble, but not both!

Forecasting Fire on Scottish TV News

On 29 Nov 2010 Dr Guillermo Rein was interviewed by Scottish TV about a recent research paper published about "Forecasting  Fire Growth".




On the same day he was interviewed for BBC Radio Scotland and  The Scotsman.

Fertilizer fire aboard cargo ship

A recent journal paper titled "Small-scale experiments of self-sustaining decomposition of NPK fertilizer and application to the events aboard the Ostedijk in 2007" has published in Journal of Hazardous Materials. Its content is presented here.


The global fertilizer industry produces 170 million tonnes of fertilizer annually. As the global population increases and countries develop, this is expected to rise. Production sites are limited to locations with good availability of key raw materials. Therefore, large quantities are required to be shipped to the point of use.

Fertilizers contain three main ingredients essential for plant growth: nitrogen, phosphorous and potassium (NPK). These are present in various forms, however it is the presence of ammonium nitrate that constitutes the biggest risk. Ammonium nitrate is classified as a Dangerous Good by the UN Recommendations on the Transport of Dangerous Goods. This is because in the presence of an initiating event, ammonium nitrate will undergo self-sustaining decomposition. This is a chain reaction that occurs when a molecule of ammonium nitrate breaks down and releases heat which allows the decomposition of further molecules. In the presence of organic material this may result in explosion as in Texas City (1947) in which 581 people were killed.

Figure: The Ostedijk on 21st February (the 5th day) after the hold was opened and before specialized fire-fighting activities had commenced. Derived from photograph courtesy of Agencia EFE.

The research presented here gives an experimental insight into the decomposition of NPK fertilizers, highlights some of the limitations of the current UN Recommendations and applies the results to the events aboard the cargo ship Ostedijk in 2007.

The Ostedijk was carrying a cargo on NPK fertilizer from Norway to Spain when an accidental decomposition reaction occurred. The decomposition continued for seven days before it was stopped by partial flooding of the cargo hold as previous attempts to cool the cargo had been unsuccessful. During this time, a large plume of toxic gases formed and the crew had to be evacuated from the ship.

This unique set of experiments was performed in the laboratory using NPK 16.16.16, an industrially available fertilizer, and three different apparatus. The propagation behaviour was studied in an apparatus similar to that proposed by the UN test. Thermo-gravimetric analysis was performed to identify the reactions occurring and investigate the reaction mechanism. Finally, the state of the art for testing reactive materials, the Fire Propagation Apparatus, was used to find the conditions under which the reaction would become self-sustaining and to measure the heat of reaction.

The experiments showed beyond doubt that NPK 16.16.16 can undergo a self-sustaining decomposition reaction. This results in temperatures up to 350°C and releases heat at a rate of 1.8 MJ/kg of reacting fertilizer. This is in contradiction to the UN classification that the material is free from the hazard of self-sustaining decomposition. The paper allows us to understand and quantify some of the observations during the accidental event aboard the Ostedijk.

Figure: (a) Unreacted fertilizer granules and (b) cross section showing partially reacted sample with 4 phases visible.

These experiments are important as there is very little research in the open literature regarding decomposition of ammonium nitrate containing fertilizers and this is the first time such measurements have been applied to a real scenario. They also provide an insight into this complex risk and the controlling mechanisms. The data and experimental methods can be used to further investigations into other incidents which may help in identifying causes of, and reduce losses from, this phenomenon.

FireGrid: An e-infrastructure for next-generation emergency response support

by Dr Sung-Han Koo

A recent journal paper titled "FireGrid: An e-infrastructure for next-generation emergency response support" has been published in the Journal of Parallel and Distributed Computing. Its content is presented here.

The costs of fire are great, commonly estimated in the range of 1-2% of GDP. Despite this, emergency service intervention at fires is often reliant upon very basic information (i.e. fire alarm panel information) or simple “gut instinct” of experienced fire officers. This need not be the case in the modern era, when a range of technologies are available which, if effectively harnessed, could transform the way in which fire emergencies are tackled, thereby significantly impacting the costs associated with failures. Here we describe development and demonstration of a novel concept which integrates sensor technologies, fire simulation, High Performance Computing (HPC) and knowledge-based reasoning, to provide an “intelligent” emergency response system known as FireGrid.

The heart of the system is the sensor-linked fire model (described in more detail in reference 17). While fire simulation has found wide application historically for design purposes, the uncertainties of fire development defeat any attempt to provide a true predictive capability of hazard evolution, generally precluding real-time use. We bypass these uncertainties by continually updating our model with a flow of sensor-derived information regarding conditions in the building. The modelling strategy exploits Monte-Carlo techniques in combination with Bayesian inference for “steering”; being “embarrassingly parallel” in nature it is ideal for implementation on multiprocessor HPC systems. The output contains embedded probabilistic information about the likelihoods of various future hazard conditions, encompassing both threat to humans (i.e. escaping occupants, and incoming fire and rescue personnel) and to the building itself (in terms of structural weaknesses, or collapse potential). The interpreted information is conveyed rapidly to the end user, i.e. the “incident commander”, to provide decision support information that can effectively assist their intervention strategies.



Initial application of a system such as FireGrid would be most relevant to high-risk and critical infrastructures, including tall buildings. It is readily apparent that better information to incident commanders could be vital in avoiding scenarios comparable to the World Trade Center tragedies, where emergency responders continued intervention operations totally oblivious to the impending
collapse of the towers. FireGrid is an ambitious vision, and its success also depends upon an effective partnership and engagement with potential end users. Our initial project was undertaken in conjunction with various members of the UK fire and rescue services, culminating in a live fullscale demonstration test attended by a broad audience including a senior fire officer. The complex evolution of the fire, with unexpected behaviours and ultimate transition to “flashover”, was an ideal test of the sensor-linked model running on the grid, and the system capabilities were effectively demonstrated. Further development of such systems extends a genuine hope that some of the chronic and long-standing problems associated with accidental fires might be eventually be overcome, with wide–ranging benefits to all relevant stakeholders.


Editor note: A related paper is discussed in "Towards the forecast of fire dynamics to assist the emergency response"

Lloyd’s Science of Risk Prize goes to Fire Technology

Congratulations to Dr Francesco Colella for winning the Lloyd’s Science of Risk Prize in the Technology Category.

The prize was for his research paper "A Novel Multiscale Methodology for Simulating Tunnel Ventilation Flows During Fires" (published in Fire Technology). He led this work as a Research Associate at The School of Engineering from 2007 to 2010.

Dr Richard Ward, CEO of Lloyds told Francesco "The judging panel, comprising experts from academia and insurance felt your paper illustrated how novel computational methods can be used to reduce fire risk in the future. The panel were particularly impressed with how you reduced model run-time by concentrating on what is critical and by coupling fast and slower models".

This is Lloyd’s research prize for academics and aims at keeping the world’s leading specialist insurance market with the pace of academic knowledge and cutting edge thinking.


On top of this winning paper, The University of Edinburgh had three more papers short-listed as the top of each category (two of them from the fire group as well):

* Mr Craig Poland, short-listed in Technology Risk (best runner up), from the School of Medicine for his paper "Carbon nanotubes introduced into the abdominal cavity of mice show asbestos-like pathogenicity"  (published in Nature Nanotechnology).

* Dr Wolfran Jahn, short-listed in Technology Risk, from the School of Engineering for his paper "Forecasting Fire Growth using an Inverse Zone Modelling Approach" (published in Fire Safety Journal).

* Dr Claire Belcher, short-listed in Climate Change Risk, from the School of Geosciences for her paper "Increased fire activity at the Triassic/Jurassic boundary in Greenland due to climate-driven floral change" (published in Nature Geoscience).

See related article Hot talent in risk research in the Staff Bulletin of the University of Edinburgh.
See press release by Springer.

Fire Scholarships from The Lloyd’s Register Educational Trust

New Fire Safety Engineering scholarships from The Lloyd’s Register Educational Trust aim to make buildings safer from fire.


Modern buildings and the people who live and work in them will be better protected from the risk and consequences of fire, thanks to new education and research initiatives within the BRE Centre for Fire Safety Engineering at the University of Edinburgh.

Researchers at the University of Edinburgh are aiming for a better understanding of how contemporary building features – such as lighter construction materials and open-plan interiors – can influence how fires take hold and how fast they spread.

More than £200K in new student scholarships supported by The Lloyd’s Register Educational Trust will help to create a core of leaders who will use new understanding to bring change to the field.

Research and teaching programmes will seek to influence safety planning and design such as building evacuation procedures, fire-safe construction, and guidance for firefighters.

Top-flight undergraduate and postgraduate scholarship students will be recruited to create a cohort of fire safety specialists with expertise in all aspects of modern fire safety techniques.

Three LRET international MSc scholars will be sponsored through a new two-year International MSc in Fire Safety Engineering (IMFSE). The degree, the first multi-institution course of its kind globally, is operated by the Universities of Edinburgh, Lund and Ghent and funded by the European Commission’s Erasmus Mundus programme.

A further six LRET International MEng scholars will be supported in their final two years of the existing degree in Structural and Fire Safety Engineering at the University of Edinburgh.

Dr Luke Bisby, a researcher at the University of Edinburgh’s BRE Centre for Fire Safety Engineering, said: “Building design has changed radically in recent decades – we need a pioneering approach to developing fire safety solutions. We have to ensure that the chances of fire are as low as possible and that if a fire should occur, it will have little chance to spread, everyone inside can be evacuated safely, and economic and environmental losses can be minimised. Only through research linked to innovative educational programs can new approaches to fire safety take hold.”

Michael Franklin, Director of The LRET commented: “The Lloyd’s Register Educational Trust funds exceptional students studying science, engineering and technology throughout the world. We want to encourage and help them to become the future leaders in their chosen field. We hope The LRET scholarships at the University of Edinburgh will help to increase fire safety significantly in the years to come.”

The 2010 winners of the LRET Scholarships are (from left in the photo below):

• Ieuan Rickard, LRET MEng Scholar in Fire Safety Engineering
• Sarah Higginson, LRET MEng Scholar in Fire Safety Engineering
• Eduardo Maciel, LRET International MSc Scholar in Fire Safety Engineering

Congratulations to all three of the winners!

For further information, please contact:
Dr Luke Bisby, School of Engineering, tel 0131 650 5710; email Luke.Bisby@ed.ac.uk.


Notes:

The Lloyd’s Register Educational Trust is an independent charity that was established in 2004. Its principal purpose is to support advances in transportation, science, engineering and technology  education, training and research worldwide for the benefit of all. It also funds work that enhances the safety of life and property at sea, on land and in the air.