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Les emissions mundials de gasos d'efecte hivernacle han augmentat a nivells sense precedents, provocant un fort enfocament en la descarbonització. L’hidrogen, especialment quan es produeix de manera renovable, emergeix com un vector d’energia prometedor i lliure de CO2 per als sectors de la indústria, el transport i l’energia. Nogensmenys, la transició a l’hidrogen implica desafiaments tècnics significatius, particularment en la producció contínua i l’emmagatzematge segur. Classificat com una substància perillosa segons la Directiva SEVESO III, l’hidrogen planteja riscos d’accidents greus, fet que requereix una rigorosa Avaluació Quantitativa de Riscos (QRA). L’estimació precisa de les conseqüències és crítica per a una avaluació fiable de riscos. Aquest treball va realitzar una anàlisi de referència de les eines de programari Phast, HyRAM i ALOHA per avaluar les seves capacitats en la modelització de la dispersió i la ignició d’hidrogen gasós de fuites de tancs pressuritzats, centrant-se en la precisió dels seus resultats. Per validar els resultats de les simulacions s’han utilitzat dades experimentals de tres estudis, cobrint pressions de 60 a 400 bars i diàmetres d’orificis de 0.5 mm a 52.5 mm. ALOHA presenta limitacions significatives ja que no va poder produir resultats per a la majoria dels estudis experimentals que involucraven dolls d’hidrogen a petita i mitjana escala perquè no proporciona resultats per a distàncies menors a 10 metres i només simula dolls de foc verticals. La comparació de Phast i HyRAM ha mostrat que ambdues eines generalment subestimen les concentracions d’hidrogen, amb Phast funcionant lleugerament millor que HyRAM, especialment en concentracions més altes. Ambdues eines tendeixen a sobreestimar la longitud de la flama, excepte en les simulacions de l’orifici de fuita més petit. Per a dolls de foc a gran escala, Phast va sobreestimar la radiació, mentre que HyRAM la va subestimar., Les emisiones mundiales de gases de efecto invernadero han aumentado a niveles sin precedentes, provocando un fuerte enfoque en la descarbonización. El hidrógeno, especialmente cuando se produce de manera renovable, emerge como un vector de energía prometedor y libre de CO2 para los sectores de la industria, el transporte y la energía. No obstante, la transición al hidrógeno implica desafíos técnicos significativos, particularmente en la producción continua y el almacenamiento seguro. Clasificado como una sustancia peligrosa según la Directiva SEVESO III, el hidrógeno plantea riesgos de accidentes graves, lo que requiere una rigurosa Evaluación Cuantitativa de Riesgos (QRA). La estimación precisa de las consecuencias es crítica para una evaluación fiable de riesgos. Este trabajo realiza un análisis de referencia de las herramientas de software Phast, HyRAM y ALOHA para evaluar sus capacidades en la modelización de la dispersión y la ignición de hidrógeno gaseoso de fugas de tanques presurizados, centrándose en la precisión de sus resultados. Para validar los resultados de las simulaciones se han utilizado datos experimentales de tres estudios, cubriendo presiones de 60 a 400 bares y diámetros de orificios de 0.5 mm a 52.5 mm. ALOHA presenta limitaciones significativas ya que no pudo producir resultados para la mayoría de los estudios experimentales que involucraban chorros de hidrógeno a pequeña y mediana escala porque no proporciona resultados para distancias menores a 10 metros y solo simula dardos de fuego verticales. La comparación de Phast y HyRAM ha mostrado que ambas herramientas generalmente subestiman las concentraciones de hidrógeno, con Phast funcionando ligeramente mejor que HyRAM, especialmente en concentraciones más altas. Ambas herramientas tienden a sobreestimar la longitud de la llama, excepto en las simulaciones del orificio de fuga más pequeño. Para dardos de fuego a gran escala, Phast sobreestimó la radiación, mientras que HyRAM la subestimó., Global greenhouse gas emissions have surged to unprecedented levels, prompting a strong focus on decarbonization. Hydrogen, especially when produced renewably, emerges as a promising CO2-free energy vector for industry, transport, and power sectors. However, the transition to hydrogen involves significant technical challenges, particularly in continuous production and safe storage. Classified as a hazardous substance under the SEVESO III Directive, hydrogen poses risks of major accidents, necessitating rigorous Quantitative Risk Assessment (QRA). Accurate consequence estimation is critical for reliable risk assessment. This study conducted a benchmark analysis of Phast, HyRAM, and ALOHA software tools to evaluate their capabilities in modelling the dispersion and ignition of gaseous hydrogen from pressurized tank leaks, focusing on the accuracy of their results. Real-world experimental data from three studies were used to validate simulation outcomes, covering pressures from 60 to 400 bar and hole diameters from 0.5 mm to 52.5 mm. ALOHA demonstrated significant limitations in this study. It was unable to produce results for most experimental studies involving small and medium-scale hydrogen jets because it does not display distances shorter than 10 meters and is restricted to simulating vertical jet fires only. The comparison of Phast and HyRAM revealed that both tools generally underestimated hydrogen concentrations, with Phast performing slightly better than HyRAM, especially at higher concentrations. Atmospheric stability influenced dispersion but not jet fire characteristics. Both tools tended to overpredict flame length, except in the smallest release hole simulations. For large-scale jet fires, Phast overpredicted radiation, while HyRAM underpredicted it., Incoming

La freqüència i la gravetat dels incendis forestals han augmentat principalment a causa del canvi climàtic i l'escalfament global. Els incendis forestals que es desenvolupen a les zones on coexisteixen indústries i vegetació, també coneguda com a Interfície Forestal-Industrial (WII, del seu acrònim en anglès), poden provocar greus accidents tecnològics. S'han publicat algunes investigacions per avaluar el risc d'incendi a les zones WII, però pocs estudis s’han centrat en el mapeig d’aquestes àrees. Johnston & Flannigan (2018) i més recentment, Planas et al. (2023), han proposat dues metodologies per fer el mapeig de la WII a diferents parts del món utilitzant dades basades en format ràster i vector, respectivament. L'objectiu principal del present estudi ha estat comparar ambdues metodologies. Per fer-ho, s'ha utilitzat com a cas de prova l'àrea geogràfica de Catalunya. Utilitzant mapes de vegetació del conjunt de dades Corine Land Cover del Servei de Monitorització de la Terra de Copernicus, el present treball compara les diferències en el càlcul de l'índex d'agregació, una mètrica del paisatge utilitzada per modelar la capacitat de la vegetació per propagar incendis forestals. Els resultats han demostrat la validesa de la metodologia proposada per Planas et al. (2023). Addicionalment s’ha analitzat la situació dels 158 establiments Seveso a Catalunya i la seva proximitat a zones WII. Els resultats han mostrat que el 2% d’aquestes industries es troben completament envoltades de zones WII, mentre que el 20% es troben parcialment envoltades., La frecuencia y gravedad de los incendios forestales han aumentado principalmente debido al cambio climático y al calentamiento global. Los incendios forestales que se producen en las zonas donde coexisten industrias y vegetación, también conocidas como Interfaz Forestal-Industrial (WII, de su acrónimo en inglés), pueden provocar graves accidentes tecnológicos. Se han publicado algunas investigaciones para evaluar el riesgo de incendio en zonas WII, pero pocos estudios se centraron en mapear estas áreas. Johnston & Flannigan (2018) y más recientemente, Planas et al. (2023), han propuesto dos metodologías para mapear zonas WII en diferentes partes del mundo utilizando datos basados en formato ráster y vector, respectivamente. El principal objetivo del presente estudio fue comparar ambas metodologías. Para ello se utilizó como caso de prueba el área geográfica de Cataluña. Utilizando mapas de vegetación del conjunto de datos Corine Land Cover del Servicio de Monitoreo Terrestre Copernicus, este trabajo se centra en comparar las diferencias en el cálculo del índice de agregación, una métrica del paisaje utilizada para modelar la capacidad de la vegetación para propagar incendios forestales. Los resultados demostraron la validez de la metodología propuesta por Planas et al. (2023). Adicionalmente se ha analizado la situación de los 158 establecimientos Seveso en Cataluña y su proximidad a zonas WII. Los resultados han mostrado que el 2% de estas industrias se encuentran completamente rodeadas de zonas WII, mientras que el 20% se encuentran parcialmente rodeadas., The frequency and severity of wildfires have increased mainly due to climate change and global warming. Wildfires located in areas where industries and vegetation coexist, also known as the Wildland-Industrial Interface (WII), can cause serious technological accidents. Some research has been published to assess the risk of fire in WII zones, but few studies focused on mapping these areas. Johnston & Flannigan (2018) and more recently, Planas et al. (2023), have proposed two methodologies to map WII in different parts of the world using data based on raster and vector formats, respectively. The main objective of the present study was to compare both methodologies. To do this, the geographical area of Catalonia was used as test case. Using vegetation maps from the Corine Land Cover data set of the Copernicus Land Monitoring Service, the present work compares the differences in the calculation of the aggregation index, a landscape metric used to model the capability of the vegetation to propagate wildland fire. The results demonstrated the validity of the methodology proposed by Planas et al. (2023). Additionally, the situation of the 158 Seveso establishments in Catalonia and their proximity to WII areas has been analysed. The results have shown that 2% of these industries are completely surrounded by WII zones, while 20% are partially surrounded.

Deliverable D1.1 del projecte europeu WUITIPS, Preprint

This paper presents an experimental study on horizontally jet flames with rather high velocities (58 m/s-167 m/s, Reynolds number up to 3.0 × 105), which mainly fall in the momentum-controlled region. Both high-speed schlieren and color imaging techniques have been adopted to obtain the time-resolved images, based on which the flame and flow dynamics has been discussed comprehensively. Under the test conditions, all the flames have shown lift-off characteristics. The dynamic mode decomposition (DMD) and proper orthogonal decomposition (POD) analysis has been performed to reveal the flame and flow fluctuating frequency and the corresponding spatial distribution. The results have shown two high frequency modes at 269 Hz and 537 Hz in the lifted-off jet region, which may come from the test bench vibration. The statistics of flame length, height and lift-off distance have been presented, which have been compared with previously reported data at lower velocities. The comparison indicates that the flame behaviors have shown quite dramatic differences in the buoyancy and momentum-controlled regions. The present experiments have extended the research of horizontally placed jet flames to a wider velocity range, which has greatly broadened our knowledge of the lift-off jet flame behaviors under high velocity conditions., Peer Reviewed, Postprint (author's final draft)

As WUI fires have become a global concern, there is a growing need for engineering methodologies that lead to proactive fire management not only at the landscape level, but at all WUI scales. This paper presents a quantitative methodology for structural vulnerability assessment at the WUI settlement level that is based on 10 indicators, established for the different fire exposure phases a WUI area experiences (pre-impact, impact and fire transfer) as well as on other factors that can escalate vulnerability. As output, a Structural Vulnerability Index (SVI) for the entire analyzed area can be obtained. The methodology can not only assess vulnerability of WUI settlements in a quantitative way, but it can also quantify the effect of measures employed for the reduction of this vulnerability. Additionally, the methodology is suitable for comparison between different settlements or neighborhoods of the same area. A case study for the city of Barcelona, Spain, is presented, in which 9 WUI neighborhoods are analyzed and vulnerability reduction measures are prioritized., This research is funded by the Barcelona City Council and “La Caixa” Foundation (project WUICOM-BCN, 21S09274-001), the project PID2020-114766RB-100 of MCIN/AEI/10.13039/501100011033 and the project TED2021-130484B-100, funded by MCIN/AEI/10.13039/501100011033 and the European Union “NextGenerationEU”/PRTR. The authors also want to thank Bombers de Barcelona, the Consortium of the Natural Park of Collserola for their help in data gathering and the Pau Costa Foundation. A. Águeda is a Serra-Húnter fellow., Peer Reviewed, Postprint (published version)

Background. Wildland–urban interface (WUI) fires pose great challenges to firefighting services and there is a growing need for self-protection and the creation of fire-adapted communities. Aim. A tool that can aid homeowners and residents of the Mediterranean WUI was created so that they can identify vulnerabilities present on their properties and consequently reduce them in order to reduce the risk of fires igniting dwellings. Methods. This Vulnerability Assessment Tool is based on a fault tree analysis that includes possible structural vulnerabilities as well as the different ways a fire could spread on a property to finally enter and ignite a dwelling. The probabilities of the different events are obtained from fuzzy preferences of WUI experts. Key results. Our system was tested against real-world data taken from two WUI fires that occurred in 2021 and 2022 in Spain in which several dwellings were affected, with different degrees of damage (minor to major losses). Conclusions. The tool is able to show the vulnerabilities of the properties and to account for differences in building characteristics and vegetation management at the parcel scale. Implications. A planned use of this tool would be key to improving fire resilience at the community level., Peer Reviewed, Postprint (published version)

Over the past years, wildfires have raged with unprecedented intensity across the world, becoming a growing problem, as weather conditions conductive to wildfire ignition and spread will increase in frequency and severity worldwide. This, coupled with a growing human expansion, leads to an increase in wildfire risk and in the threat to wildland-urban interface (WUI) communities. Commonly, definitions for WUI areas consider homes, commercial facilities, office and public buildings. This excludes industrial installations, where wildfires can trigger accidents or cascading events leading to extremely dangerous situations for the population causing enormous economic losses. In this paper, the problem associated to the wildland-industrial interface (WII) is analyzed. A methodology to obtain a global WII map is described, and the first WII maps for Europe and Asia are provided. Results show that, in Europe, 2.5% of the land and 6% of vegetated areas are WII, while in Asia these are respectively 0.24% and 0.5%. An analysis of how wildfire triggered industrial accidents can be considered when performing quantitative risk assessments (QRA) in industrial sites is also performed, identifying the current state of the art and research gaps, with the aim of helping industry, public authorities and policy makers, for better accident prevention, preparedness and response., This research is funded by the project PID2020-114766RB-100 of MCIN/AEI/10.13039/501100011033 and the project 2021_SGR_00251 of Generalitat de Catalunya. A. Àgueda is a Serra Hunter fellow., Peer Reviewed, Postprint (published version)

En els pròxims anys, es preveu que els vehicles elèctrics i d’hidrogen substitueixin als tradicionals de combustió per tal de reduir les emissions contaminants i fer front el canvi climàtic. No obstant, els riscs associats als incendis en aquest vehicles no són tan coneguts. Això podria provocar un augment dels accidents greus, especialment en espais tancats com són els aparcaments subterranis, on el limitat volum d’aire pot agreujar les conseqüències. Per mitigar aquests riscs, és recomanable instal·lar sistemes de ventilació en aquests espais, i més particularment, els de ventilació per impulsos (IVS per les seves sigles en anglès). Aquests semblen una solució rentable i versàtil per extreure l’aire contaminat i, a la vegada, proporcionar una entrada d’aire net. Diversos estudis han avaluat el comportament del foc produït pels cotxes elèctrics i d’hidrogen, així com el rendiment dels IVS en aquests aparcaments. S’ha constatat que els incendis en vehicles elèctrics es comporten de manera similar als vehicles de combustió en quant a productes alliberats i alliberament de calor. Per una altra part, aquests sistemes resulten prometedors a l’hora d’extreure l’excés d’hidrogen, evitant la formació de núvols inflamables. Tot i així, avaluar el seu rendiment en l’extracció del fum dels vehicles elèctric s’esdevé un repte degut a la manca d’estudis de casos reals o simulats. En general, la transició als vehicles elèctrics i d’hidrogen hauria d’anar acompanyada de la implantació de sistemes de ventilació eficaços, com els IVS, per mitigar les possibles conseqüències dels incendis, sobretot en espais tancats., En los próximos años, se espera que los vehículos eléctricos y de hidrógeno sustituyan a los de combustión tradicional para reducir las emisiones contaminantes y hacer frente al cambio climático. Sin embargo, los riesgos asociados a los incendios en estos vehículos no son tan conocidos. Esto podría provocar un aumento de los accidentes graves, sobre todo en recintos cerrados como aparcamientos subterráneos, donde el limitado volumen de aire puede agravar las consecuencias. Para mitigar estos riesgos, se recomienda la instalación de sistemas de ventilación, en particular los de ventilación por impulsos (IVS, por sus siglas en inglés). Estos parecen una solución rentable y versátil para extraer el aire contaminado y proporcionar simultáneamente una entrada de aire limpio. Diversos estudios han evaluado el comportamiento frente al fuego de los vehículos eléctricos y de hidrógeno y el rendimiento de los IVS en los aparcamientos. Se ha constatado que los incendios en vehículos eléctricos se comportan de forma similar a los vehículos de combustión en cuanto a la liberación máxima de calor y los componentes liberados con la excepción del HF, que es crítico en los vehículos eléctricos. Por otra parte, los IVS resultan prometedores en la extracción del hidrógeno excedente, evitando la formación de nubes inflamables. Sin embargo, evaluar con mayor precisión su rendimiento en la extracción de humos de vehículos eléctricos es un reto debido a la falta de estudios de casos reales o simulados. En general, la transición a los vehículos eléctricos y de hidrógeno debería ir acompañada de la implantación de sistemas de ventilación eficaces, como los IVS, para mitigar las posibles consecuencias de los incendios, sobre todo en espacios cerrados., Electric and hydrogen vehicles are expected to substitute traditional combustion vehicles in the coming years to reduce contaminant emissions and address climate change concerns. However, the risks associated with fires in these vehicles are not well-known. This could lead to an increase in hazardous accidents, especially in enclosed areas like underground car parks, where the limited air volume can worsen the consequences. To mitigate these risks, ventilation systems, particularly impulse ventilation systems (IVS), are recommended. IVSs seem a cost-effective, versatile solution to extract contaminated air and provide fresh air intake simultaneously. Studies have evaluated the fire behaviour of electric and hydrogen vehicles and the performance of IVS in car parks. It has been found that fires in electric vehicles behave similarly to combustion vehicles in terms of maximum heat release and released components except for HF, which is critical in electric vehicles. On the other hand, IVSs show promising results in extracting exceeding hydrogen, preventing the formation of flammable clouds. However, assessing more precisely its performance in extracting smoke from electric vehicles is challenging due to the lack of real-case or simulated studies. Overall, the transition to electric and hydrogen vehicles should be accompanied by the implementation of effective ventilation systems, such as IVSs, to mitigate the potential consequences of fires, particularly in enclosed spaces.

A wide range of equipment (boilers, furnaces, reformers, etc.) in industrial processes use fired combustion chambers to retrieve heat from a fuel. Although these systems have been used since long time and their safety has been significantly improved, explosions related with disturbances in the firing chamber still occur with certain frequency. The experimental testing of these explosions is challenging due to the complex design and large volume of combustion equipment, along with the presence of internal elements (heating tubes, burners, ignitors) and explosion relief panels. Moreover, empirical explosion evaluation methods may lack accuracy by not considering overpressure reflections and the effects of internal elements. Computational Fluid Dynamics (CFD) models are becoming nowadays accessible and runnable with ordinary desktop computers. In the present work, GEXCON FLACS software has been used to evaluate the effects of explosions inside combustion chambers. The results obtained confirm the potential utility of CFD simulations to analyze this type of explosions., Peer Reviewed, Postprint (published version)

Aquest treball s'emmarca dins del camp d'estudi de les xarxes neuronals en Aprenentatge profund. L'objectiu del projecte és analitzar i aplicar les xarxes neuronals que hi ha avui dia en el mercat per resoldre un problema en específic. Aquest és tracta de la segmentació de plomalls de fum en incendis forestals. S'ha desenvolupat un estudi de les xarxes neuronals utilitzades per resoldre problemes de segmentació d'imatges i també una reconstrucció posterior en 3D d'aquests plomalls de fum. L'algorisme finalment escollit és tracta del model UNet, una xarxa neuronal convolucional basada en l'estructura d'autoencoders amb connexions de pas, que desenvolupa tasques d'autoaprenentatge per finalment obtenir una predicció de la classe a segmentar entrenada, en aquest cas plomalls. de fum. Posteriorment, una comparativa entre algoritmes tradicionals i el model UNet aplicat fent servir aprenentatge profund s'ha realitzat, veient que tant quantitativament com qualitativament s'aconsegueix els millors resultats aplicant el model UNet, però a la vegada comporta més temps de computació. Tots aquests models s'han desenvolupat amb el llenguatge de programació Python utilitzant els llibres d'aprenentatge automàtic Tensorflow i Keras. Dins del model UNet s'han dut a terme múltiples experiments per obtenir els diferents valors dels hiperparàmetres més adequats per a l'aplicació del projecte, obtenint una precisió del 93.45 % en el model final per a la segmentació de fum en imatges d'incendis. forestals., Este trabajo se enmarca dentro del campo de estudio de las redes neuronales en aprendizaje profundo. El objetivo del proyecto es analizar y aplicar las redes neuronales que existen hoy en día en el mercado para resolver un problema en específico. Éste se trata de la segmentación de penachos de humo en incendios forestales. Se ha desarrollado un estudio de las redes neuronales utilizadas para resolver problemas de segmentación de imágenes y también una reconstrucción posterior en 3D de estos penachos de humo. El algoritmo finalmente escogido se trata del modelo UNet, una red neuronal convolucional basada en la estructura de autoencoders con conexiones de paso, que desarrolla tareas de autoaprendizaje para finalmente obtener una predicción de la clase a segmentar entrenada, en este caso penachos de humo. Posteriormente, una comparativa entre algoritmos tradicionales y el modelo UNet aplicado utilizando aprendizaje profundo se ha realizado, viendo que tanto cuantitativa como cualitativamente se consigue los mejores resultados aplicando el modelo UNet, pero a la vez conlleva más tiempo de computación. Todos estos modelos se han desarrollado con el lenguaje de programación Python utilizando libros de aprendizaje automático Tensorflow y Keras. Dentro del modelo UNet se han llevado a cabo múltiples experimentos para obtener los distintos valores de los hiperparámetros más adecuados para la aplicación del proyecto, obteniendo una precisión del 93.45 % en el modelo final para la segmentación de humo en imágenes de incendios forestales., This work is framed within the field of study of neural networks in Deep Learning. The aim of the project is to analyse and apply the neural networks that exist today in the market to solve a specific problem. This is about the segmentation of smoke plumes in forest fires. A study of the neural networks used to solve image segmentation problems and also a subsequent 3D reconstruction of these smoke plumes has been developed. The algorithm finally chosen is the UNet model, a convolutional neural network based on the structure of autoencoders with step connections, which develops self-learning tasks to finally obtain a prediction of the class to be trained, in this case smoke plumes. Also, a comparison between traditional algorithms and the UNet model applied using deep learning has been carried out, seeing that both quantitatively and qualitatively the best results are achieved by applying the UNet model, but at the same time it involves more computing time. All these models have been developed in the Python programming language using the Tensorflow and Keras machine learning books. Within the UNet model, multiple experiments have been carried out to obtain the different hyperparameter values most suitable for the project application, obtaining an accuracy of 93.45% in the final model for smoke segmentation in wildfire images.

Tesi amb menció internacional, (English) Wildfires that reach the border between the wildland and urban areas, defined as the Wildland-Urban Interface (WUI), have rapidly expanded in frequency and severity over the past few decades, and the number of structures lost each year has increased significantly. As WUI fires pose great management challenged in terms of civil protection and fire mitigation, self- protection has become a growing necessity and focus must be placed in creating fire-adapted communities that can safely co-exist with wildfires. At the WUI microscale (i.e., homeowner level), susceptibility of a home to wildfire depends on the management of its surroundings and the hardening of the structure itself. The goal of this thesis is to develop a risk analysis framework based on the analysis of the fire hazard posed by the fuels located in the surroundings of a building and on the identification of building vulnerabilities for Mediterranean WUI scenarios. To meet this goal, an analysis of the different types of fuels present on a property and of the vulnerable elements of a building is performed and three scenarios are selected for further analysis with performance-based strategies. Performance criteria are identified for each of the selected scenarios and an analysis of the available information on the fire characteristics of the different types of fuels located at the microscale is presented, which highlights a lack of quantitative knowledge on WUI fire hazards. Real-scale tests of four fuel packs that contain artificial fuels that could be present in WUI environments have therefore been performed, and the obtained results can be used for the analysis of WUI fire scenarios. A methodology for the quantitative analysis of the vulnerability of building and property sub-systems based on a Performance- Based Design (PBD) approach is presented and applied to the three selected WUI scenarios. The methodology includes the modelling of the scenarios with the Computational Fluid Dynamics tool FD, (Català) Els incendis forestals que arriben a la frontera entre les zones amb vegetació i les àrees urbanes, definides com la Interfície Urbana-Forestal (IUF), s'han expandit ràpidament en freqüència i severitat durant les últimes dècades, i el nombre d'estructures perdudes cada any ha augmentat significativament. Com que els incendis IUF suposen grans desafiaments a nivell de gestió en termes de protecció civil i mitigació d'incendis, l'autoprotecció s'ha convertit en una necessitat creixent i cal centrar l'atenció en la creació de comunitats adaptades al foc que puguin coexistir amb els incendis forestals de manera segura. A nivell micro-escala de la IUF (és a dir, al nivell del propietari de l’habitatge), la susceptibilitat d'una casa als incendis forestals depèn de la gestió dels seus voltants i de la resistència de l'estructura en si mateixa. L'objectiu d'aquesta tesi és desenvolupar un marc d'anàlisi de riscos basat en l'anàlisi del perill d'incendi que presenten els combustibles situats als voltants d'un edifici i en la identificació de les vulnerabilitats pròpies dels edificis per als escenaris de la IUF mediterrània. Per complir aquest objectiu, s'analitzen els diferents tipus de combustibles presents en una propietat i els elements vulnerables dels edificis, i es seleccionen tres escenaris per a una anàlisi més detallada amb estratègies basades en prestacions. Es defineixen criteris de prestacions per a cada un dels escenaris seleccionats i es presenta una anàlisi de la informació disponible sobre les característiques d'incendi dels diferents tipus de combustibles situats al micro-escala, la qual mostra que hi ha una manca de coneixement quantitatiu sobre els perills dels incendis a la IUF. Per tant, s'han realitzat proves a escala real de quatre conjunts d’elements que contenen combustibles artificials i que solen estar presents en entorns de la IUF. Els resultats obtinguts es facilitaran l'anàlisi d'escenaris d'incendi de la IUF. Es presenta i s'aplica u, Postprint (published version)

Deliverable D.2.1 del projecte europeu WUITIPS, Preprint

The purpose of this thesis is to assess the sensitivity of the results of quantitative risk analysis (QRA). The first step was to reproduce a QRA for the MILES S.A plant, a simulated reference company. In carrying out the analysis, all the required steps were followed as described in Instruction 14 in force in Catalonia, regulating the conduct of the QRA. After having identified and described the primary events, a frequency value equal to that given in the BEVI manual was attributed to each type of scenario identified and then it was adapted to the process conditions. The evolution of primary events was assessed using the method of quantified event trees, necessary to link the primary event with the possible accidentalscenarios that can be generated from them. In addition, with this method the final accidental scenario frequency of occurrence was also evaluated as the frequency of the initial accidental scenario multiplied by the probability product on each branch of the event tree. The next step was to describe the accident scenarios identified in terms of the physical variables that characterise these scenarios (overpressure, thermal radiation, concentration). The physical variables obtained were used as input to the Probit equations required to calculate the lethal concentrations associated with both the substance and the final accident scenario under consideration. Once all the necessary data had been collected, the risk around the plant was calculated, represented by isorisk curves (curves joining all points with the same risk value). The sensitivity of the results was assessed by changing one of the input parameters of the QRA, the frequency of the primary event, which is a determining factor in calculating the risk associated to a given accidental scenario. The change that influenced the variation in the final results was assessed by examining how the isorisk curves changed in diameter, with particular reference to the 10-6 value curve representing the limit, El objetivo de esta tesis es evaluar la sensibilidad de los resultados del análisis cuantitativo de riesgos (ACR). El primer paso fue reproducir un ACR para la planta de MILES S.A, una empresa de referencia simulada. En la realización del análisis se siguieron todos los pasos requeridos por la Instrucción 14 vigente en Cataluña, que regula la realización del ACR. Una vez identificados y descritos los sucesos primarios, se atribuyó a cada tipo de escenario identificado un valor de frecuencia igual al indicado en el manual BEVI y se adaptó a las condiciones del proceso. La evolución de los sucesos primarios se evaluó mediante el método de los árboles de sucesos cuantificados, necesario para relacionar el suceso primario con los posibles escenarios de accidente que pueden generarse a partir de ellos. Además, con este método también se evaluó la frecuencia de ocurrencia del escenario accidental final como la frecuencia del escenario accidental inicial multiplicada por el producto de la probabilidad en cada rama del árbol de sucesos. El siguiente paso fue describir los escenarios de accidente identificados en términos de las variables físicas que caracterizan estos escenarios (sobrepresión, radiación térmica, concentración). Las variables físicas obtenidas se utilizaron como entrada para las ecuaciones Probit necesarias para calcular las concentraciones letales asociadas tanto a la sustancia como al escenario de accidente final considerado. Una vez recogidos todos los datos necesarios, se calculó el riesgo en torno a la central, representado por curvas de isorriesgo (curvas que unen todos los puntos con el mismo valor de riesgo). La sensibilidad de los resultados se evaluó cambiando uno de los parámetros de entrada del QRA, la frecuencia del suceso primario, que es un factor determinante en el cálculo del riesgo asociado a un determinado escenario de accidente. El cambio que influyó en la variación de los resultados finales se evaluó examinando cómo cambiaban de diámetro, L'objectiu d'aquesta tesi és avaluar la sensibilitat dels resultats de l'anàlisi quantitatiu de riscos (QRA). El primer pas va ser reproduir un AQR per a la planta MILES S.A, una empresa de referència simulada. En la realització de l'anàlisi s'han seguit tots els passos requerits tal com es descriu a la Instrucció 14 vigent a Catalunya, que regula la conducta del AQR. Després d'haver identificat i descrit els esdeveniments primaris, es va atribuir a cada tipus d'escenari identificat un valor de freqüència igual al que indica el manual BEVI, i després, es va adaptar a les condicions del procés. L'evolució dels esdeveniments primaris s'ha avaluat mitjançant el mètode dels arbres d'esdeveniments quantificats, necessaris per vincular l'esdeveniment primari amb els possibles escenaris d'accident que se'n poden generar. A més, amb aquest mètode també es va avaluar la freqüència d'ocurrència de l'escenari accidental final com la freqüència de l'escenari accidental inicial multiplicada pel producte de probabilitat a cada branca de l'arbre d'esdeveniments. El següent pas va ser descriure els escenaris d'accident identificats en funció de les variables físiques que els caracteritzen (sobrepressió, radiació tèrmica, concentració). Les variables físiques obtingudes, es van utilitzar com a dades de entrada a les equacions de Probit, necessàries per calcular les concentracions letals associades, tant a la substància, com a l'escenari final d'accident considerat. Un cop recollides totes les dades necessàries, es va calcular el risc al voltant de la planta, representat per corbes d'isorisc (corbes que uneixen tots els punts amb el mateix valor de risc). La sensibilitat dels resultats es va avaluar canviant un dels paràmetres d'entrada del QRA, la freqüència de l'esdeveniment primari, que és un factor determinant en el càlcul del risc associat a un determinat escenari d'accident. El canvi que va influir en la variació dels resultats finals es va avaluar examinant com les corbes d'is, Incoming

En este siglo, el consumo global de materiales peligrosos ha aumentado. Esto se debe a que, en los últimos años, las actitudes de la industria con respecto a los compuestos peligrosos, que son componentes clave de muchos bienes comerciales esenciales, han cambiado significativamente. Estos materiales exigen una precaución especial ya que pueden tener graves consecuencias para la salud y el medio ambiente. El objetivo principal de esta tesis es identificar y analizar los peligros del almacenamiento de sustancias pirofóricas, a las que la exposición al aire y al agua puede provocar la ignición. Entre todos los productos químicos pirofóricos empleados regularmente en la industria, el trietilaluminio (TEA) ha llamado la atención de esta tesis en términos de su amplia gama de usos como un componente catalítico eficiente, un aditivo con combustible para microencapsulación, en el diseño de aeronaves y en aplicaciones militares. El TEA se obtiene básicamente a partir de aluminio, hidrógeno y etileno en un proceso de uno o dos pasos. El TEA es un líquido de incoloro que se auto inflama y reacciona violentamente con aire y agua. Como resultado, se liberarán gases combustibles a alta temperatura como hidrógeno, cuya concentración aumenta a medida que aumenta la temperatura del sistema. Las industrias de procesamiento y las operaciones relacionadas con el TEA están expuestas al riesgo de varios accidentes graves, como incendios de balsa causados por derrames de combustible, que es uno de los incidentes no intencionales más frecuentes en un entorno industrial. Los daños causados por un incendio de TEA están relacionados principalmente con el calor irradiado en el área circundante. Entonces, para analizar y predecir los peligros esperados del TEA puro y su almacenamiento en solución, Se ha marcado como objetivo de esta tesis el cálculo de calor recibido por un objetivo determinado. El modelado experimental de incendios es una técnica habitual utilizada para generar rápidamente es, In this century, the global consumption of hazardous materials has risen. This is because, in recent years, industry attitudes regarding hazardous compounds, which are key components of many essential commercial goods, have changed significantly. These materials demand extra caution since they can have serious health and environmental consequences. The main goal of this thesis is to identify and analyze the hazards of storing pyrophoric substances that exposure to the environment or other materials at ambient temperatures can cause these materials to ignite. These analyses are used to develop the storage and handling hazards. Among all the pyrophoric chemicals regularly employed in industry, Triethyl aluminum (TEA) has piqued this thesis's attention in terms of its wide range of uses as an efficient catalytic component, an additive with fuel for micro-encapsulation, in aircraft design, and in the military area. TEA is basically prepared from aluminum, hydrogen, and ethylene in a one or two-step process. TEA is a colorless liquid that self-ignites and reacts violently with air and water. As a result, high heat and combustible gases such as hydrogen will be released, the concentration of which increases as the system temperature rises. The processing industries and related operations for TEA as a hazardous commodity are exposed to the risk of various serious accidents, such as pool fires caused by fuel spills which is one of the most prevalent unintentional incidents in an industrial setting. The damages caused by a TEA fire are mainly connected to the heat radiated in the surrounding area. So, in order to analyze and predict the expected hazards of neat TEA and its solution storage, the heat received by a given target was computed using various classical equations, the most frequent of which are compiled in this thesis. At the same time, experimental data for neat TEA and its solutions has also been collected to be compared. The empirical fire modeling is a generaliz

seven story building made of shipping containers is planned to be built in Barcelona, Spain. This study mainly aimed to evaluate the fire performance of one of these residential shipping containers whose walls and ceiling will have a shaft wall system installed. The default assembly consisted of three fire resistant gypsum boards for vertical panels and a mineral wool layer within the framing system. This work aimed to assess if system variants (e.g. less gypsum boards, no mineral wool layer) could still be adequate considering fire resistance purposes. To determine if steel temperatures would attain a predetermined temperature of 300-350ºC (a temperature value above which mechanical properties of steel start to change significantly) the temperature evolution within the shaft wall system and the corrugated steel profile of the container was analysed under different fire conditions. Diamonds simulator (v. 2020; Buildsoft) was used to perform the heat transfer analysis from the inside surface of the container (where the fire source was present) and within the shaft wall and the corrugated profile. To do so gas temperatures near the walls and the ceiling were required, so these temperatures were obtained from two sources: (1) The standard fire curve ISO834; (2) CFD simulations performed using the Fire Dynamics Simulator (FDS). Post-flashover fire scenarios were modelled in FDS taking into account the type of fuel present in residential buildings according to international standards. The results obtained indicate that temperatures lower than 350ºC were attained on the ribbed steel sheet under all the tested heat exposure conditions. When changing the assembly by removing the mineral wool layer, fire resistance was found to still be adequate. Therefore, under the tested conditions, the structural response of the containers would comply with fire protection standards, even in the case where insulation was reduced., Postprint (published version)

Wildfires are uncontrolled fires involving the combustion of wild vegetation. When a wildfire front approaches the Wildland-Industrial Interface there can be a serious threat for process and storage equipment items located at the plant boundary. Ensuring the integrity of such equipment prevents the fire from spreading inside the plant site and causing major accidents such as fire, explosion, and toxic gas dispersion. The provision of adequate clearance areas is paramount since the early stages of the plant design. Once the facility is built, the implementation of safety measures can protect industrial items and ensure tank integrity. A tailored methodology for the calculation of safety distances between wild vegetation and tanks accounting for the safety system was developed and applied to a case study. The outcomes provide useful information on the effectiveness of safety measures for the protection of industrial items exposed to wildfire., Peer Reviewed, Postprint (published version)

The combustion of artificial fuels at Wildland-Urban Interface (WUI) homeowner scale has been identified as a contributor to fire spread through a property, often leading to the ignition of structures, hence involving major safety issues at community level. However, little information on the real-scale burning behaviour of these type of fuels is available. These fuels are usually located close to the main structure of a property and are often piled together, forming packs containing different types of materials. Real-scale tests on four different fuel packs have been performed to gather quantitative data on items that are commonly present on WUI properties. The fuel packs consisted of typical combustible materials present in porches, gardens, backyards or stored in secondary structures. Data on Heat Release Rate (HRR), Mass Loss Rate, fire load, smoke species concentration, heat flux, temperature and flame height are provided. The duration of the fires was between 49 and 83 min. Peak HRR values between 383 kW and 2.55 MW were recorded, along with flame heights up to 3.6 m. Radiative heat fluxes were calculated for each test, and safe distances for people were identified. Reported data can be used to quantify vulnerabilities of WUI properties through Performance-Based Design methodologies. Results show that the most hazardous fuel packs out of the four tested are those containing pallets, cardboard, paint, foam mats and garden furniture. In all cases, the flaming area expanded significantly increasing the risk of fire spread through a property even after the passage of the wildfire front., Peer Reviewed, Postprint (author's final draft)

Wildfires pose a growing threat to populated areas around the world and especially in the Mediterranean Basin. Numerous Mediterranean cities have typically developed neighbourhoods that expand into forest land in which basic aspects for an efficient WUI fire management have not been considered. In this paper, we present a holistic approach to analyse threats to metropolitan areas due to WUI fires, accounting for infrastructural, societal and ecosystems vulnerability at settlement scale. Based on design fires and the key parameters responsible of fire impact and percolation through communities of most probable WUI fire events, we define key indicators to describe how vulnerable structures are in WUI metropolitan areas. Following, urban and societal indicators are selected to account for population’s vulnerability and, finally, ecosystems potential losses are accounted by ecosystem vulnerability indicators such as ecosystem sensitivity and adaptability. We have implemented this methodology to analyse vulnerability in Barcelona WUI areas and identified those that can be more threatened in case of wildfire. Results of this study will be key to inform risk-reduction public policies, as they provide particular insights on those WUI areas within Barcelona municipality that should be prioritized along with the specific issues that should be tackled., Peer Reviewed, Postprint (published version)

WUI fires are posing great challenges to firefighting services, which are overwhelmed by the need to not only suppress the fire, but also protect the community. The need for self-protection is therefore growing, as is the need for the creation of fire-adapted communities. A tool that can aid homeowners and residents of the WUI is therefore created, so that they can identify the vulnerabilities present on their properties and consequently reduce them in order to diminish the risk of damage due to a wildfire. This Vulnerability Assessment Tool is based on a fault tree analysis that includes possible structural vulnerabilities as well as the different ways a fire could spread on a property to finally enter and damage the building. The identification of the probabilities of the different events in the fault tree is obtained through the use of fuzzy logic, for which inputs, outputs and rules are identified. A questionnaire targeted to homeowners and based on the fault tree and linked to the probability identified with fuzzy logic is then developed. By filling in this questionnaire, homeowners at the WUI will be able to know what the probability of a fire entering their house is. The result of the questionnaire also indicates which are the issues on the property that need to be addressed in order to lower this probability. Finally, the tool is validated with a case study of several houses affected by a fire in Spain., Postprint (published version)

Among the major accidents that can occur in process plants and in the transportation of hazardous materials, those involving fire are the most frequent ones. And one type of fire which has been the origin of severe accidents are the jet fires, originated by the ignition of a flammable gas/vapour or spray, released through a hole, a broken pipe, a flange, etc. Jet fires often occur in rather compact process or storage plants, and the probability of flame impingement on another equipment is rather high. In such a case, very high heat fluxes can exist, with quick and severe effects on that equipment implying a probable domino effect. The present study aims to contribute to the knowledge and prediction of the main features of jet fires, focusing on the distance over which flames impingement can occur. New expressions are proposed to predict this distance for the case of horizontal subsonic and sonic hydrocarbon jet fires, from both experimental data and the mathematical and computational modelling of the main geometrical (size, length, reach) features of the flame., Preprint

Els accidents tecnològics causats per esdeveniments naturals o NaTech events són una amenaça creixent per a les instal·lacions industrials perquè les seves conseqüències són habitualment ignorats en les anàlisis quantitatives de riscs (ACR) convencionals. Terratrèmols, inundacions, tempestes, activitat volcànica, etc. suposen un risc amb conseqüències severes per a les plantes químiques i industrials i, per tant, els seus impactes han d'ésser estudiats. En aquesta tesi, una recopilació d'esdeveniments NaTech provocats per incendis forestals és portada a terme per reflectir la freqüència d'aquesta mena d'esdeveniments junt amb les seves conseqüències, localitzacions i tipus d'instal·lacions més comunament afectades. Es porta a terme una anàlisi més detallada de dos accidents concrets fent servir els mètodes Bow-Tie i MTO (Man, Technology and Organization). A més a més, es desenvolupa i aplica un model per realitzar ACRs d'accidents causats per incendis forestals, els resultats dels quals són comparats amb els obtinguts mitjançant un ACR convencional., Los accidentes tecnológicos causados por eventos naturales o NaTech events son una amenaza creciente para las instalaciones industriales debido a que sus consecuencias son comúnmente ignorados en los análisis cuantitativos de riesgos (ACR) convencionales. Terremotos, inundaciones, tormentas, actividad volcánica, etc suponen un riesgo con consecuencias severas para las plantas químicas e industriales y, por lo tanto, sus impactos han de ser estudiados. En esta tesis, una recopilación de eventos NaTech provocados por incendios forestales es llevada a cabo para reflejar la frecuencia de este tipo de eventos junto con sus consecuencias, localizaciones y tipo de instalaciones más comúnmente afectadas. Se lleva a cabo un análisis más detallado de dos accidentes concretos usando los métodos Bow-Tie y MTO (Man, Technology and Organization). Además, se desarrolla y aplica un modelo para realizar ACRs de accidentes causados por incendios forestales, cuyos resultados son comparados con los obtenidos mediante un ACR convencional., Technological accidents triggered by natural events or NaTech events are a rising threat to industrial facilities since their consequences have been typically overlooked in conventional quantitative risk analysis (QRA). Earthquakes, floods, storms, volcanic activity, etc. suppose a risk with severe consequences to chemical and industrial installations and, therefore, their effects must be addressed. In this thesis, a survey of NaTech accidents and incidents triggered by wildfires is performed in order to reflect the frequency of this type of events along with their consequences and the locations and types of installations more commonly affected. A more detailed analysis of specific accidents is carried out making use of the Bow-Tie and MTO (Humans, Technology and Organization) analysis. Besides, a model for QRA of accidents caused by wildfires is developed and applied in a case study where a comparison between the results of the recently developed model and the ones obtained through a conventional approach is performed.

A historical analysis was carried out on 189 accidents that occurred in gas and oil fuel fired equipment. The variation of frequency as a function of time, the main causes leading to a fire or an explosion, as well as the consequences of the accidents were studied. Explosion was the most frequent accident, followed by fire; in a few cases the final outcome was a release. Accidents in gas fired combustion equipment were significantly more frequent than those in the liquid fired ones. The main causes were tube rupture and/or error in ignition/reignition sequences, followed by loss of flame in the combustion chamber and, with a minor frequency, entrance of non-expected fuel and presence of non-combusted materials. The consequences on people were much more important in case of explosions than in case of fires. Even though the equipment involving combustion chambers can be considered essentially safe, this historical analysis has shown that accidents continue to occur with certain frequency because the number of existing units is quite high and the possibility of human error during its operation and maintenance is still significant., Postprint (author's final draft)

Wildfire occurrence frequency is increasing worldwide, generating more and more concern, especially in Wildland-Urban interfaces (WUI) and Wildland-Industrial Interfaces (WII) areas. Wildfires approaching WII can cause severe damage to people and industrial assets. In these scenarios, storage tanks present in industrial installations are among the most vulnerable pieces of equipment, since they are usually located in the proximity of the plant boundary. If hazardous substances are stored, tank damage caused by the fire can lead to loss of containment and trigger technological accident scenarios, escalating the consequences. Preserving the integrity of this type of equipment in case of wildfires is of paramount importance. The present study proposes a stepwise methodology for the evaluation of safety distances between storage tanks and vegetation that may be affected by a wildfire. According to the available data on the wildfire, on the lay-out and on the tanks that are likely to be affected, the methodology provides safety distances that may be applied to design fuel-reduced fringes around the industrial facility. The methodology proposed represents a quantitative tool for the calculation of safety distances that can guide industrial managers and assist regulators in the definition of more reliable standards. The comparison of the safety distances resulting from the present study with regulations and guidelines currently in use in different countries rises concern about the possible underestimation of required safety distances in the case of severe wildfires., Peer Reviewed, Postprint (published version)

Measuring wildland fire behaviour is essential forfire science and fire management. Aerial thermal infrared (TIR)imaging provides outstanding opportunities to acquire suchinformation remotely. Variables such as fire rate of spread(ROS), fire radiative power (FRP) and fire line intensity maybe measured explicitly both in time and space, providing thenecessary data to study the response of fire behaviour to weather,vegetation, topography and firefighting efforts. However, raw TIRimagery acquired by Unmanned Aerial Vehicles (UAVs) requiresstabilization and georeferencing before any other processing canbe performed. Aerial video usually suffers from instabilitiesproduced by sensor movement. This problem is especially acutenear an active wildfire due to fire-generated turbulence. Fur-thermore, the nature of fire TIR video presents some specificchallenges that hinder robust inter-frame registration. There-fore, this paper presents a software-based video stabilizationalgorithm specifically designed for thermal infrared imageryof forest fires. After a comparative analysis of existing imageregistration algorithms, the KAZE feature-matching method wasselected and accompanied by pre- and post-processing modules.These included foreground histogram equalization and a multi-reference framework designed to increase the algorithm’s robust-ness in the presence of missing or faulty frames. Performanceof the proposed algorithm was validated in a total of ninevideo sequences acquired during field fire experiments. Theproposed algorithm yielded a registration accuracy between 10and 1000 times higher than other tested methods, returned 10xmore meaningful feature matches and proved robust in thepresence of faulty video frames. The ability to automaticallycancel camera movement for every frame in a video sequencesolves a key limitation in data processing pipelines and opensthe door to a number of systematic fire behaviour experimentalanalyses. Moreover, a completely automated process suppo, Peer Reviewed, Postprint (author's final draft)

Pel què fa al transport de materials perillosos per canonades, l’aparició d’un doll de foc és un dels accidents més freqüents en cas de pèrdua de contenció. A la llum d'aquesta consideració, és necessària una estimació adequada de l'escenari d'accident per determinar la magnitud del risc i les mesures necessàries per evitar o mitigar-ne les conseqüències. La dinàmica de fluids computacional representa una eina vàlida que s’utilitzarà en aquest marc, per la seva capacitat per descriure l’evolució de l’accident, tenint en compte els obstacles i els factors específics del lloc. En aquest treball s’analitza la capacitat del codi FLACS CFD per simular un doll de foc horitzontal de propà i el codi es valida amb dades experimentals proporcionades per Vahid Forughi (Foroughi et al., 2019). Els paràmetres utilitzats per a la validació són les característiques geomètriques doll de foc i la temperatura de la flama. L'avaluació es realitza comparant diferents models numèrics disponibles al codi FLACS per tal de definir el més adequat per descriure aquesta tipologia d’incendi. Després, la precisió dels resultats de la simulació s’avalua mitjançant paràmetres estadístics. En conclusió, els resultats mostren que el codi FLACS CFD és capaç de descriure els dolls de foc horitzontals amb una bona concordança amb les dades experimentals, tot i que amb una lleu sobrepredicció, Con respecto al transporte de material peligroso por tuberías, la ocurrencia de un dardo de fuego es uno de los accidentes más comunes en caso de pérdida de contención. A la luz de esta consideración, es necesaria una estimación adecuada del escenario del accidente para determinar la magnitud del riesgo y las medidas necesarias para evitar o mitigar sus consecuencias. La dinámica de fluidos computacional representa una herramienta válida para ser utilizada en este marco, por su capacidad para describir la evolución del accidente, considerando los obstáculos y los factores específicos del lugar. En este trabajo se analiza la capacidad del código FLACS CFD para simular un dardo de fuego horizontal de propano y se valida el código contra datos experimentales proporcionados por Vahid Forughi (Foroughi et al., 2019). Los parámetros utilizados para la validación son las características geométricas del dardo de fuego y la temperatura de la llama. La evaluación se realiza comparando diferentes modelos numéricos disponibles en código FLACS con el fin de definir el más adecuado para describir esta tipología de incendio. Luego, la precisión de los resultados de la simulación se evalúa utilizando parámetros estadísticos. En conclusión, los resultados muestran que el código FLACS CFD es capaz de describir los fenómenos de fuego de dardo horizontal con una buena concordancia con los datos experimentales, aunque con un ligero exceso de predicción., With regard to pipeline transportation of hazardous material, the occurrence of a jet fire is one of the most common accident in case of loss of containment. In light of this consideration, an appropriate estimation of the accident scenario is necessary to determine the magnitude of the risk and the required measures to avoid or mitigate the consequences. Computational Fluid Dynamic represents a valid tool to be used in this framework, because of its capability to describe the evolution of the accident, considering the obstacles and the site-specific factors. In this work the capacity of FLACS CFD code to simulate a propane horizontal jet fire is analysed and the code is validated against experimental data provided by Vahid Forughi (Foroughi et al., 2019). The parameters used for the validation are the jet fire geometrical characteristics and the flame temperature. The assessment is performed comparing different numerical models available in FLACS code in order to define the most appropriate to describe horizontal jet-fires. Then, accuracy of simulation results is assessed using statistical performance metric parameters. In conclusion, results show that FLACS CFD code is able to describe the horizontal jet fire phenomena with a good accordance with experimental data, even though with a slight overprediction., Incoming

Quan un incendi forestal amenaça una zona habitada, l’opció més segura que normalment es considera és l’evacuació precoç. Tot i això, diversos factors poden dificultar que les persones evacuïn de forma segura. Els principals motius són la incapacitat de proporcionar o rebre un avís precoç, o que les xarxes de carreteres dificultin la sortida de forma ràpida. És en aquestes circumstàncies que el confinament pot ser l’opció més viable. Aquest projecte té com a objectiu principal estudiar en quines condicions és possible dur a terme aquest confinament i quines mesures s’han de tenir en compte per tal que sigui segur. Aquest projecte té com a objectiu específic crear i analitzar un escenari d’Interfície Urbano-Forestal (WUI; de l’anglès) mitjançant les eines del simulador Fire Dynamics Simulator (FDS) i demostrar així la seva utilitat en l’estudi d’aquest tipus d’escenaris. Un incendi i, com a conseqüència, el fum d’aquest sempre comporta una gran dificultat per predir la seva evolució ja que cada escenari és completament diferent. L’evolució del plomall de foc i de les condicions tòxiques a la casa han sigut detallades amb èxit. A més, s’ha pogut demostrar la importància de l’efecte tèrmic, superior a la de l’efecte tòxic, a l’hora de considerar el confinament durant un incendi., Cuando un incendio forestal amenaza una zona habitada, la opción que normalmente se considera más segura es la evacuación precoz. Sin embargo, varios factores pueden dificultar que las personas evacuen de forma segura. Los principales motivos son la incapacidad de proporcionar o recibir un aviso precoz, o que la red de carreteras dificulte la salida de forma rápida. Es en estas circunstancias cuando el confinamiento puede ser la opción más segura. Este proyecto tiene como objetivo principal estudiar en qué condiciones es posible este confinamiento y qué medidas se deben tener en cuenta para que sea seguro. Este proyecto tiene como objetivo específico crear y analizar un escenario de Interfaz Urbano-Forestal (WUI; del inglés) mediante las herramientas del simulador Fire Dynamics Simulator (FDS) y demostrar así su utilidad en el estudio de este tipo de escenarios. Un incendio, y como consecuencia, el humo de éste siempre conlleva una gran dificultad para predecir su evolución porque cada escenario es completamente diferente. La evolución de la columna de humo producida durante un incendio así como las condiciones tóxicas dentro de la casa han sido detalladas con éxito. Además, ha sido posible demostrar la importancia del efecto térmico, superior a la del efecto tóxico, en el momento de considerar el confinamiento durante un incendio., When an populated zone is threatened by a wildland fire, the safest option usually considered is an early evacuation. However, several factors may avert people from evacuating safely. The main reasons are the inability to provide or receive an early warning, or road networks that hinder a rapid departure. It is under these circumstances that shelter may be the safest option. The main objective of this project is to study under what conditions this shelter is possible and what measures must be taken. This project aims to specifically create and analyse a Wildland-Urban Interface (WUI) scenario through the use of the Fire Dynamic Simulator (FDS) and thus demonstrate its usefulness in the study of this type of scenarios. A fire and, as a result, its smoke always involves a great difficulty in predicting its evolution because each scenario is completely different. The evolution of the fire plume and toxic conditions within the house of the main simulation has been detailed successfully. Moreover, it has been possible to prove the importance of the thermal effects over toxic effects, while considering the sheltering during a wildfire.

Fires at the Wildland-Urban Interface (WUI) are becoming increasingly hazardous for life safety and property protection. Guidelines and standards for fire practitioners are needed in order to help WUI communities face this threat and become fire-adapted. A performance-based design approach (PBD) is proposed to deal with the complex issues present at the WUI homeowner scale, which entails the use of Computational Fluid Dynamics (CFD) tools such as FDS in order to identify vulnerabilities in a quantitative manner. An analysis of recent European WUI fires is presented, along with the definition of several pattern scenarios that can be derived from these. Based on this analysis, examples of PBD fire scenarios specific for the Mediterranean WUI microscale are presented, involving glazing systems, roofing and gutters, external structures adjacent to the main building, and gaps present in the building envelope. A worked example to show the implementation of the proposed PBD method is provided in which the fire impact of residential fuel on a glazing system is quantitatively analysed., Award-winning, Postprint (author's final draft)

The concept of the Dispersion Safety Factor (DSF) was introduced by Vílchez et al., 2013, Vílchez et al., 2014 and has been revisited in this work. The DSF is defined as the ratio between the flammable region of the vapor cloud (set at a concentration equal to the low flammability level (LFL)) and the corresponding visible boundary of the cloud. We have used a computational fluid dynamics model (FLACS v.10.4) to simulate the dispersion of two liquefied flammable fuels (LNG and propane). DSF results have been analyzed using main effects and interaction plots, and a complementary metric (DSF50) has been introduced in order to establish more conservative threat areas in flammable vapor cloud scenarios. We have observed an interaction between relative humidity and wind velocity for DSF in the low-to-medium range of RH and wind velocity values. Four regression models have been proposed for the computation of DSF and DSF50 for LNG and propane dependent on ambient wind velocity and relative humidity. Contour plots have been prepared to be used as a practical tool, because through the reading of these plots the DSF (and DSF50) can be obtained immediately given wind velocity and relative humidity data., Peer Reviewed, Postprint (author's final draft)

Accidental jet fires occurring in industrial facilities can involve severe consequences as they can trigger domino effect. The assessment of the flame-geometry descriptors of the jet can contribute to prevent flame impingement on plant equipment, hence reducing inventory loss and structural collapse. This paper reports the geometrical features of vertical methane subsonic jet flames at normal and sub-atmospheric pressures: 1.0 atm, 0.9 atm, 0.8 atm, 0.7 atm and 0.6 atm. Differences on flame shape are evaluated, and linear correlations of the main geometrical parameters of interest (i.e. lift-off distance, radiant flame length, and equivalent diameter) are defined as a function of the Reynolds number. Moreover, the predictive capabilities of FDS, FireFOAM and FLACS-Fire codes are assessed when determining the geometrical features of jet fire experiments. Based on a qualitative and a quantitative comparison between simulation results and experimental data, the main strengths and weaknesses of each code are identified. Recommendations on suitable grid sizes are delivered., Peer Reviewed, Postprint (author's final draft)

En aquest treball s’ha dut a terme una recerca bibliogràfica sobre el desbordament tèrmic en piles d’ió liti en l’àmbit automobilístic elèctric. S’ha realitzat una investigació teòrica sobre les piles, el seu funcionament, la seva composició, la funcionalitat i la tipologia d’aquestes. La literatura fa referència a tres models de piles diferents, les de níquel-cadmi, hidrur de metall de níquel i les d’ió liti. S’ha enfocat el treball a les piles d’ió liti destacant les possibles fallides d’aquestes al desbordament tèrmic, és a dir, a l’auto-escalfament derivat d’una reacció exotèrmica fora de control. Aquest fenomen pot ser degut a un abús tèrmic, físic i/o elèctric, aquest treball s’ha centrat en l’abús tèrmic en funció de la exposició de la pila a una font de calor externa. S’ha realitzat una proposta d’un dispositiu experimental per a l’estudi del procés de desbordament format per un assecador com a font d’emissió d’aire calent i una pila LXD 18650-25P3. Durant les proves de posada a punt del mètode experimental es va monitoritzar la temperatura per tal de comprovar el moment en el que s’arriba al desbordament tèrmic. S’han validat les dades obtingudes de la monitorització de temperatura amb la recerca bibliogràfica feta i s’ha arribat a concloure que en els experiments realitzats no s’arriba al desbordament tèrmic de la pila degut a la manca de potència de la font externa d’emissió de calor. La situació derivada de la pandèmia de COVID-19 ha fet impossible millorar el dispositiu experimental i la realització de més experiments.

We present the experimental performance analysis of a fire protection fabric for cars designed to protect people's life in case of fire entrapment. Two experimental burns were executed to simulate heat and smoke exposure conditions in case of vehicle entrapment in a rural road. For the first experimental burn, a 2-m high fuel bed of pine slash was arranged in a 13¿m¿×¿6 m area. Fire was ignited at one end of the fuel bed and spread wind driven (3 m/s midflame wind speed). 2.8¿m away from the other fuel bed end, a car covered with the fabric was placed parallel to the fire. Data analysis provided values of fire behavior and flame characteristics, being typical of wildfires of moderate intensity (1800¿kW/m). Maximum air temperatures inside the vehicle ranged around 41°C to 42.5°C, providing evidence of the fabric's good performance. To evaluate the degree of protection against smoke, air change rates were estimated with and without the fabric covering the car. Also, an experimental burn similar to the previous one was executed to monitor CO2 and CO concentrations inside the car. Tenable conditions for these gases were maintained during the whole test according to reviewed exposure criteria., Peer Reviewed, Postprint (author's final draft)

Document oficial del projecte WUIVIEW corresponent al WP1 de Project Management, This report summarises the degree of accomplishment of project tasks and activities as described in the Technical Annex, highlighting expenditure of efforts and resources. It is based on the monitoring and quality assurance activities and periodic reports within project life cycle, Postprint (author's final draft)

En aquest treball de fi de grau s’ha dut a terme un estudi d’una corba d’incendi per a projectes de disseny prestacional en aparcaments tancats amb l’objectiu de trobar una corba que ens proporcioni una eina fiable a la validació de dissenys de ventiladors i de protecció contra incendis amb disseny prestacional a través de simulacions CFD. L’estudi s’ha desenvolupat en dos apartats: a. Estudi bibliogràfic i presentacions de les corbes proposades En aquest apartat s’ha dut a terme una recerca bibliogràfica i s’han proposat 5 corbes: tres corbes experimentals i dues corbes teòriques, i s’han presentat dues simplificacions de cada corba experimental basant-nos en dos punts de vista diferents: - Presa de dades en intervals de dos minuts. - Màxims i mínims locals. b. Estudi de les corbes proposades En aquest apartat s’ha fet una comparació entre les cinc corbes proposades basant-nos en valors extrets de les mateixes corbes proposades a l’apartat anterior.

Incoming

El canvi climàtic està afectant cada vegada més a la humanitat, incrementant la probabilitat d’incendis forestals i agreujant les conseqüències que se’n deriven. En aquest aspecte, els habitatgeslocalitzats a la Interfície Urbana-Forestal (WUI) es veuen més afectats. Per aquesta raó, és necessari que les urbanitzacions forestals estiguin preparades per sobreviure als possibles incendis. Davant la situació exposada, l’estudi de com es comporten les finestres durant un incendi és clau per a la prevenció de la propagació d’aquests cap a l’interior de les edificacions. Aquest treball forma part del projecte europeu Wildland-Urban Interface Virtual Essays Workbench (WUIVIEW) dirigit pel Centre d’Estudis del Risc Tecnològic (CERTEC) de l’Escola d’Enginyeria de Barcelona Est (UPC-EEBE). L’objectiu general d’aquest treball és l’estudi dels efectes d’un incendi localitzat davant d’una finestra situada a la WUI, mitjançant les eines de simulació computacional Fire Dynamics Simulator (FDS) i Pyrosim. L’estudi se centra en analitzar el temps de supervivència de les finestres quan s’exposen al foc, i a les distàncies de seguretat respecte el foc, per tal de poder obtenir unes pautes que minimitzin el risc de que aquest entri a l’habitatge. El treball consisteix en la recerca bibliogràfica dels diferents experiments realitzats prèviament sobre trencament de finestres degut a l’efecte del foc, per tal de definir un criteri prestacional que garanteixi la supervivència de les finestres en un incendi. Tot seguit, es realitzen diverses simulacions per tal d’analitzar les diferents variables a tractar, com per exemple el gruix del vidre, mida de la finestra, tipus de marc, entre d’altres. Finalment, a través de la interpretació dels resultats, s’obté una idea de com aquestes variables afecten a la supervivència de les finestres. Per acabar, aquest treball forma part de la investigació per a futures directrius i recomanacions per la protecció i prevenció dels incendis en comunitats situ, El cambio climático está afectando cada vez más a la humanidad, incrementando la probabilidad de incendios forestales y agravando las consecuencias que de ellos se derivan. En este aspecto, las viviendas localizadas en la Interfaz Urbano-Forestal (WUI) se ven más afectadas. Por esta razón, es necesario que las urbanizaciones forestales estén preparadas para sobrevivir a los posibles incendios. Ante la situación expuesta, el estudio de cómo se comportan las ventanas durante un incendio es clave para la prevención de la propagación de éstos hacia el interior de las edificaciones. Este trabajo forma parte del proyecto europeo Wildland-Urban Interface Virtual Essays Workbench (WUIVIEW) dirigido por el Centro de Estudios del Riesgo Tecnológico (CERTEC) de la Escuela de Ingeniería de Barcelona Este (UPC-EEBE). El objetivo general de este trabajo es el estudio de los efectos de un incendio localizado en frente de una ventana situada en la WUI mediante las herramientas de simulación computacional Fire Dynamics Simulator (FDS) y Pyrosim. El estudio se centra en el tiempo de supervivencia de las ventanas cuando se exponen al fuego, y en las distancias de seguridad de la fuente de fuego, para poder obtener unas pautas que minimicen el riesgo de que éste entre en la vivienda. El trabajo consiste en la búsqueda bibliográfica de los diferentes experimentos realizados previamente sobre rotura de ventanas bajo el efecto del fuego, para definir un criterio prestacional que garantice la supervivencia de las ventanas en un incendio. A continuación, se realizan varias simulaciones para analizar las diferentes variables a tratar, como por ejemplo el grosor del vidrio, tamaño de la ventana, tipo de marco, entre otros. Finalmente, a través de la interpretación de los resultados, se obtiene una idea de cómo estas variables afectan a la supervivencia de las ventanas. Por último, este trabajo es una parte de la investigación para futuras directrices y recomendaciones para la protección y pre, Climate change is a big environmental problem for humanity, increasing the likelihood of forest fires and exacerbating its consequences. In this aspect, houses located at the Wildland-Urban Interface (WUI) are being increasingly affected. For this reason, these urbanized zones need to be prepared to survive the possible wildfires. Given the above situation, studying how windows behave in front of a wildfire plays a crucial role for fire prevention, especially in the WUI, since those are one of the most vulnerable parts of a house. This work is part of the European project Wildland-Urban Interface Virtual Essays Workbench (WUIVIEW) led by the Center of Technological Risk Studies (CERTEC) of the Barcelona East School of Engineering (UPC-EEBE). The general objective is to study the critical effects of a fire located in front of a window at the WUI using the simulation computational tools Fire Dynamics Simulator (FDS) and Pyrosim. The focus is placed on the survival time of glazing systems when exposed to fire, and the safety distances from the fire source, in order to obtain guidelines that minimise the risk of a fire entering a house. The present work consists on the literature research of the different experiments previously carried out on the breakage of glazing systems due to fire, with the objective of defining a performance criterion for the survivability of windows during a wildfire. Thereafter, various simulations are performed in order to analyse the different studied variables, such as the glass thickness, size of the window, type of frame, among others. Finally, through the interpretation of the results, an idea is obtained on how these variables affect the survivability of glazing systems. To conclude, this work is part of the research for future guidelines and recommendations for wildfire protection and prevention in European WUI communities.

Aerial Thermal Infrared (TIR) imagery has demonstrated tremendous potential to monitor active forest fires and acquire detailed information about fire behavior. However, aerial video is usually unstable and requires inter-frame registration before further processing. Measurement of image misalignment is an essential operation for video stabilization. Misalignment can usually be estimated through image similarity, although image similarity metrics are also sensitive to other factors such as changes in the scene and lighting conditions. Therefore, this article presents a thorough analysis of image similarity measurement techniques useful for inter-frame registration in wildfire thermal video. Image similarity metrics most commonly and successfully employed in other fields were surveyed, adapted, benchmarked and compared. We investigated their response to different camera movement components as well as recording frequency and natural variations in fire, background and ambient conditions. The study was conducted in real video from six fire experimental scenarios, ranging from laboratory tests to large-scale controlled burns. Both Global and Local Sensitivity Analyses (GSA and LSA, respectively) were performed using state-of-the-art techniques. Based on the obtained results, two different similarity metrics are proposed to satisfy two different needs. A normalized version of Mutual Information is recommended as cost function during registration, whereas 2D correlation performed the best as quality control metric after registration., Peer Reviewed, Postprint (published version)

These data are associated to the paper with the same title and are structured according to the figures in the paper. These data correspond to the research results of the WP3 of the European Project 4D-POLYSENSE., The present dataset reports the scientific results corresponding to a scientific study where a bidimensional (2D) polypropylene flexible mesh material has been converted into a fourth dimension (4D) dynamic system. The platform is composed by a fibres of isotactic polypropylene (iPP) mesh coated with thermosensitive poly(N-isopropylacrylamide-co-N,N'-methylene bis(acrylamide) (PNIPAAm-co-MBA) hydrogel, and undergoes variations in its geometry by reversible folding/unfolding behaviour. Folding and unfolding motion in aqueous solution of bilayer and monolayer systems composed by two or one layer of hydrogel, respectively, are reported in the present dataset. Furthermore, an infrared thermographic camera and an optical microscope were used to evaluate the macroscopic and microscopic structure stimulus response in air. Additionally, PP-g-PNIPAAm meshes showed an increase in the mechanical properties (bursting strength) with respect to the uncoated mesh., 1

Managing Wildland-Urban-Interface (WUI) fires is a challenging task due to the inherent complexity of the WUI environment. To ensure the success of strategies for the protection of population and structures, safety measures have to be implemented at different scales (landscape, community and homeowner). The present study is focused on the homeowner scale and deals with the threat related to the presence of LPG domestic tanks in a WUI fire scenario. Recent accidents have demonstrated that the risk associated with this type of installation is real, but often disregarded by residents. A methodology was developed, providing a set of indicators that may easily be compared with risk acceptance criteria, assessing whether the integrity of an LPG tank exposed to WUI fire scenarios is compromised or not. The methodology is applicable to a vast range of situations and at a different level of detail according to available data. A number of case studies were carried out, showing that WUI fire scenarios impacting on domestic LPG tanks complying with regulations currently adopted in several Mediterranean countries cannot be deemed safe. The methodology proposed represents an advanced tool to assist on safety distances sizing to be prescribed by standards, driving regulators towards better-informed decision-making., Peer Reviewed, Postprint (author's final draft)

Herein, a facile approach toward transforming a 2D polypropylene flexible mesh material into a 4D dynamic system is presented. The versatile platform, composed by a substrate of knitted fibers of isotactic polypropylene (iPP) mesh and a coating of thermosensitive poly(N-isopropylacrylamide-co-N,N’-methylene bis(acrylamide) (PNIPAAm-co-MBA) hydrogel, covalently bonded to the mesh surface, after cold-plasma surface treatment and radical polymerization, is intended to undergo variations in its geometry via its reversible folding/unfolding behavior. The study is the first to trace the 3D movement of a flat surgical mesh, intended to repair hernia defects, under temperature and humidity control. An infrared thermographic camera and an optical microscope are used to evaluate the macroscopic and microscopic structure stimulus response. The presence of the PP substrate and the distribution of the gel surrounding the PP threads, affect both the PNIPAAM gel expansion/contraction as well as the time of folding/unfolding response. Furthermore, PP-g-PNIPAAm meshes show an increase in the bursting strength of ˜16% with respect to the uncoated mesh, offering a strongest and adaptable system for its future implantation in human body. The findings reported offer unprecedented application possibilities in the biomedical field., Peer Reviewed, Postprint (author's final draft)

In the event of a BLEVE, the overpressure wave can cause important effects over a certain area. Several thermodynamic assumptions have been proposed as the basis for developing methodologies to predict both the mechanical energy associated to such a wave and the peak overpressure. According to a recent comparative analysis, methods based on real gas behavior and adiabatic irreversible expansion assumptions can give a good estimation of this energy. In this communication, the Artificial Neural Network (ANN) approach has been implemented to predict the BLEVE mechanical energy for the case of propane and butane. Temperature and vessel filling degree at failure have been considered as input parameters (plus vessel volume), and the BLEVE blast energy has been estimated as output data by the ANN model. A Bayesian Regularization algorithm was chosen as the three-layer backpropagation training algorithm. Based on the neurons optimization process, the number of neurons at the hidden layer was five in the case of propane and four in the case of butane. The transfer function applied in this layer was a sigmoid, because it had an easy and straightforward differentiation for using in the backpropagation algorithm. For the output layer, the number of neurons had to be one in both cases, and the transfer function was purelin (linear). The model performance has been compared with experimental values, proving that the mechanical energy of a BLEVE explosion can be adequately predicted with the Artificial Neural Network approach., Peer Reviewed, Postprint (author's final draft)

La Interfaz Urbano-Forestal (IUF) constituye uno de los escenarios de mayor riesgo en incendios forestales. Esto se debe –entre otros importantes factores –al aumento en la complejidad de la emergencia, el incremento de daños potenciales y el desvío de recursos desde el incendio hacia la protección de bienes y personas. No existe, sin embargo, un consenso científicamente basado sobre las medidas preventivas sobre la vegetación que mejor contribuyen a construir una IUF más resistente y segura frente al paso de las llamas.El objetivo de este trabajo es la adaptación al entorno mediterráneo del «Australian Standard 3959: Construction of buildings in bushfire-prone areas (AS-3959)», que estima el flujo de calor que impactará en la IUF. Se busca, de esta manera, sentar una base sólida sobre la que tomar decisiones en el ámbito preventivo (diseño de infraestructuras perimetrales de defensa y pirojardinería) y operativo (triaje de estructuras).El AS-3959 se basa en el Modelo de Cuerpo Sólido para obtener el flujo radiante incidente en los objetos cercanos a un incendio, estimando de manera precisa la potencia emisiva de la llama, su factor de vista y la transmisividad atmosférica. En este trabajo se presenta la estrategia de adaptación de este estándar a la IUF mediterránea, tanto por lo que se refiere al modelo matemático como a la implementación del mismo en un software diseñado ad-hoc. La programación de este modelo analítico ha dado lugar a una herramienta con la cual, a partir de una serie de variables de entorno (escenario, fuego y meteorología), es posible estimar el flujo de calor que impacta sobre elementos concretos de la IUF (v.gr. una ventana, un seto, un tanque de GLP, etcétera). Esta herramienta permite, además, comparar de manera gráfica y numérica el efecto que distintos tipos e intensidades de tratamientos preventivos tienen sobre el flujo de calor incidente en bienes expuestos y, por tanto, sobre la seguridad en la interfaz.Este trabajo ofrece, por lo tan, Peer Reviewed, Postprint (published version)