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Sunday, December 26, 2010

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.

Monday, December 20, 2010

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.

Saturday, December 11, 2010

Prof Jose Torero's Christmas Lecture

Fire: A story of fascination, familiarity and fear

University of Edinburgh Christmas Lecture 2010
Presented by Prof Jose Torero
Recorded Wednesday 8th December 2010

Prof Jose Torero with the Tam Dalyell medal.

Wednesday, December 08, 2010

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"