A challenge for fire researchers is obtaining data from those fires that are most dangerous and costly. While it is feasible to instrument test beds, test plots, and small prescribed burns for research, it is uncommon to successfully instrument an active wildland fire. With a focus on very specific facets of wildland fire, researchers have created many unique models utilizing matchsticks, cardboard, liquid fuel, excelsior, plywood, live fuels, dead fuels, and wood cribs of different packing densities. Such scale models, however, only serve as valid substitutes for the full-scale system when all functional relations of the scale model are made similar to corresponding relations of the original phenomena. The field of study of large wildland fires therefore was in need of a framework that researchers could use to relate the results from many previous experiments to full-scale wildland fires; this framework was developed during the research for this dissertation. This further work developing laws for instability scaling in wildland settings was founded on the established work in dynamic similitude of G.I. Taylor, H. C. Hottel, F. A. Williams, R. I. Emori, K. Saito and Y. Iguchi. Additionally, in this work, a new dynamic flame parameter was incorporated into the scaling laws for fires that had not previously been assessed and proved to provide additional, important insight into flame spread. The new dynamic parameter enabled improved St-Fr correlations and was established for a wide range of fire sizes and fuel types.

Les travaux menés dans cette thèse concernent le développement d'un dispositif de vision permettant l'estimation de caractéristiques géométriques d'un feu de végétation en propagation. Ce dispositif est composé de plusieurs systèmes de stéréovision multimodaux générant des paires d'images stéréoscopiques à partir desquelles des points tridimensionnels sont calculés et les caractéristiques géométriques de feu tels que sa position, vitesse, hauteur, profondeur, inclinaison, surface et volume sont estimées. La première contribution importante de cette thèse est la détection de pixels de feu de végétation. Tous les algorithmes de détection de pixels de feu de la littérature ainsi que ceux développés dans le cadre de cette thèse ont été évalués sur une base de 500 images de feux de végétation acquises dans le domaine du visible et caractérisées en fonction des propriétés du feu dans l'image (couleur, fumée, luminosité). Cinq algorithmes de détection de pixels de feu de végétation basés sur la fusion de données issues d'images acquises dans le domaine du visible et du proche-infrarouge ont également été développés et évalués sur une autre base de données composée de 100 images multimodales caractérisées. La deuxième contribution importante de cette thèse concerne l'utilisation de méthodes de fusion d'images pour l'optimisation des points appariés entre les images multimodales stéréoscopiques.La troisième contribution importante de cette thèse est l'estimation des caractéristiques géométriques de feu à partir de points tridimensionnels obtenus depuis plusieurs paires d'images stéréoscopiques et recalés à l'aide de relevés GPS et d'inclinaison de tous les dispositifs de vision.Le dispositif d'estimation de caractéristiques géométriques à partir de systèmes de stéréovision a été évalué sur des objets rigides de dimensions connues et a permis d'obtenir les informations souhaitées avec une bonne précision. Les résultats des données obtenues pour des feux de végétation en propagation sont aussi présentés. / This thesis presents the geometrical characteristics measurement of spreading vegetation fires with multimodal stereovision systems. Image processing and 3D registration are used in order to obtain a three-dimensional modeling of the fire at each instant of image acquisition and then to compute fire front characteristics like its position, its rate of spread, its height, its width, its inclination, its surface and its volume. The first important contribution of this thesis is the fire pixel detection. A benchmark of fire pixel detection algorithms and of those that are developed in this thesis have been on a database of 500 vegetation fire images of the visible spectra which have been characterized according to the fire properties in the image (color, smoke, luminosity). Five fire pixel detection algorithms based on fusion of data from visible and near-infrared spectra images have also been developed and tested on another database of 100 multimodal images. The second important contribution of this thesis is about the use of images fusion for the optimization of the matching point’s number between the multimodal stereo images.The second important contribution of this thesis is the registration method of 3D fire points obtained with stereovision systems. It uses information collected from a housing containing a GPS and an IMU card which is positioned on each stereovision systems. With this registration, a method have been developed to extract the geometrical characteristics when the fire is spreading.The geometrical characteristics estimation device have been evaluated on a car of known dimensions and the results obtained confirm the good accuracy of the device. The results obtained from vegetation fires are also presented.

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The average intensity and frequency of wildland fires have been on the rise over the years, leading to an increase in the risk to homes located in the Wildland-Urban Interface (WUI). Fire suppression is the most used method of wildland fire control, but this suppression can cause wildland fires to become more frequent and devastating. Increased development in the WUI also puts these homes at greater risk. Current methods of passive fire protection are effective, but these methods are expensive, time consuming to set up, and not fully effective. This research proposes a permanent passive fire protection system that is built into the structure. A flame- resistant material would be attached to the sheathing with the roofing and siding attached over the material. This system would allow the easily replaceable exterior components of the structure to burn, and the interior of the structure would be protected. This system protects the structural supports of the building, so the house does not collapse, and the exterior components can be replaced. To test this permanent passive fire protection system 21 small-scale specimens were constructed with five different flame-resistant materials and three different types of siding. The flame-resistant materials include structural wrap, Kaowool, ceramic fiber insulation, Pyrogel, and intumescent paint. The sidings include wood siding, vinyl siding, and hardie board. The testing took place in a burn room to simulate the conditions of a wildland fire. Post-burn charring evaluations and temperature analyses were conducted to determine which type of material and siding were most effective at protecting the small-scale models. The charring evaluation included determining the percent charring of the OSB face of the specimens, and the temperature analysis included determining the percent difference between the internal and external temperatures of the specimens. The performance, cost and installation, constructability, and replaceability of each of the materials were considered in deciding which materials were most effective. Overall, the Pyrogel outperformed the other materials, but this material is by far the most expensive. The ceramic fiber material was overall the second most effective flame-resistant material, and this material could be as effective as the Pyrogel if used in conjunction with the other materials tested. Further testing of material combinations is required to determine if different flame-resistant material combinations could be as effective as the Pyrogel material on its own. The results of this project did prove the feasibility of a permanent passive fire protection system, but further testing of large-scale specimens is required to test the effectiveness of the system in more complex circumstances.

I utilized forest growth model (FVS-FFE) and fire simulation software (FlamMap, Randig), integrated through GIS software (ArcMap9.3), to quantify the impacts varied landscape-scale fuel treatments have on short-term onsite carbon loss, long-term onsite carbon storage, burn probability, conditional flame length, and mean fire size. Thirteen fuel treatment scenarios were simulated on a 42,000 hectare landscape in northern California: one untreated, three proposed by the US Forest Service, and nine that were spatially-optimized and developed with the Treatment Optimization Model in FlamMap. The nine scenarios developed in FlamMap varied by treatment intensity (10%, 20%, and 30% of the landscape treated) and treatment type (prescribed fire, mastication and thin + burn). Each scenario was subjected to 10,000 simulated wildfires with random ignition locations in order to develop burn probability and average flame length values for each scenario. I also recorded mean fire size for each scenario. I used the burn probability values to represent the likelihood of future wildfire occurrence, which I incorporated into our long-term onsite carbon storage projections. Our results suggest that the influence landscape-scale fuel treatments have on carbon dynamics and fire behavior metrics (mean burn probability, flame length and mean fire size) are highly dependent upon the treatment arrangement, type, and intensity. The results suggest that treating 20% of the landscape maximizes long-term carbon storage and that prescribed fire minimizes short-term carbon loss and maximizes onsite long-term carbon storage. Treating 20% of the landscape also appears to be the optimal treatment intensity for reducing fire behavior metrics, and treating beyond this level produces diminishing returns in reduction of fire behavior. When treating 20% of the landscape, site-specific treatments appear to perform well in comparison to spatially-optimized treatments.

For roughly the past 200 years land-managers have used the practice of “muirburning” to manipulate the structure of heather (Calluna vulgaris) to create a patchwork of habitat structures able to provide forage and nesting sites for red grouse (Lagopus lagopus scoticus) as well as grazing for sheep (Ovis aries) and red deer (Cervus elaphus). This thesis investigates both the behaviour and impact of management fires in recognition of the need to develop multi-aim land management practices that ensure both continued productivity and protection of biodiversity in the face of climatic and environmental change. Fuel structure and loading are crucial controlling factors on both fire behaviour and impact governing both rate of spread and heat release to the ground surface. A visual obstruction method is developed that estimates total and fine fuel loading as well as the structure of the heather canopy. In order to adequately understand fire impact a dimensional analysis approach is taken to estimating the mass of burnt heather stems. Experiments at a number of spatial and temporal scales relate variation in heather fuel moisture content to stand structure and variation in weather conditions. Monitoring shows moisture contents to be relatively stable temporally, but spatially variable. Periods of extreme low moisture contents in early spring are associated with frozen ground, winter cuticle damage and physiological drought. Such conditions may have contributed to the large number of wildfires in 2003. A replicated plot design was used to investigate the effect of weather conditions and fuel loading on fire behaviour. An empirical approach is taken to fire behaviour modelling with equations describing rate of spread and fireline intensity being developed on the basis of fuel structure descriptors and windspeed. The theoretical negative correlation between fuel bed density and rate of spread is demonstrated to hold true for heather stands, while the impact of heterogeneity in fuel bed structure is also investigated. Redundancy Analysis is used to investigate the influence of multiple predictors on a number of aspects of fire behaviour including: rate of spread, fireline intensity, flame length and ground surface heating. Data from this and previous studies are used to ground-truth a number of fire behaviour prediction systems including BehavePlus and the Canadian Fire Behaviour Prediction System. Finally linkages between fire behaviour, fire severity and heather regeneration are investigated. A number of proxy measures of ‘Immediate Severity’ are tested and used to examine the influence of fires on plant regeneration. The post-fire development of stands is shown to relate primarily to stand age and structure before burning, and to post-fire substrates rather than variation in fire behaviour and severity.

Ce travail est consacré à l’étude expérimentale et numérique de la propagation des feux de végétation à l’échelle du laboratoire. Une méthode de suivi de front de flamme par caméras visibles a été développée pour reconstruire et mesurer les propriétés du front au cours du temps. Les données recueillies comprennent la vitesse de propagation (Rate Of Spread), l’épaisseur du front, les longueurs du contour du front, les profils de hauteur et la puissance du feu. Une campagne expérimentale de 105 expériences de propagation sur de la frisure de bois a été réalisée sur la plateforme PROMETHEI (Plateforme de Recherche Opérationnelle en Métrologie Thermique dédiée aux Essais Incendies) du laboratoire LEMTA. Elle contient notamment une étude de l’effet de la largeur et de la charge sur la dynamique de propagation (sur la vitesse et l’épaisseur). Une base de données (en libre accès sur internet) dédiée aux feux de végétation a été créée et fournit les positions du front de flamme (avant et arrière) pour 85 expériences. Un modèle de propagation Petit Monde à réseau de cellules hexagonales a été également développé en parallèle. Plusieurs approches sont proposées pour déterminer l’évolution de l’état des cellules : la première modélise le transfert radiatif alors que la deuxième se base sur une fonction de distribution identifiée. Un algorithme d’optimisation par essaims particulaires (PSO) est employé pour estimer les différents paramètres du modèle à l’aide des résultats expérimentaux. Le modèle Petit Monde est ensuite comparé à des expériences de propagation comprenant des coupures de combustible ou des rétrécissements/élargissements de la largeur du lit / This work is devoted to the experimental and numerical study of wildland fire spread at laboratory scale. A tracking fire front method using visible cameras was used in order to follow the fire front positions during the propagation and to evaluate some fire front properties. The data include the Rate Of Spread (ROS), the fire front width, the length of fire, the profile of flames and the Heat Release Rate. An experimental campaign of 105 fire spread tests with wood shaving as fuel was conducted on the PROMETHEI plateform (Plateforme de Recherche Opérationnelle en Métrologie Thermique dédiée aux Essais Incendies) of the laboratory LEMTA. This campaign was essentially focused on the effect of the fuel bed width and the fuel loading on the fire dynamics (particularly on the ROS and fire width). An open-source data base provides the positions of the front and backing fire as a function of time. A fire spread model based on the small world concept with a hexagonal cell network was developed. Two approaches were studied: the first one is based on a radiative transfer model for the definition of the cell states and the other one is based on an estimated distribution function. A particle swarm optimization (PSO) algorithm was used for the identification of the different parameters of the model using the experimental results. Then, the model was compared to other experiments included fuel breaks or narrowing/widening of the fuel bed width

Ces travaux de thèse ont porté sur le développement d’un modèle de propagation d’un incendie de forêt et son intégration dans une chaîne opérationnelle d'aide à la lutte tactique. C'est un modèle dont la propagation s'effectue sur un réseau de sites combustibles qui prend en compte les mécanismes principaux de transfert de chaleur radiatifs et convectifs des sites en feu vers les sites sains et l'environnement. Ce modèle tient également compte du relief et des conditions locales de vent et végétation. La simulation « temps réel » a nécessité deux développements distincts. Le premier a consisté à combiner la méthode de Monte Carlo à un algorithme génétique pour créer une base de données des facteurs de vue radiatifs de la flamme sur la végétation environnante, pour une large gamme de propriétés de flammes et de conditions environnementales. Le second repose sur une méthode de suivi du front de feu afin de limiter les données manipulées aux seules données utiles au calcul de sa propagation. La phase de validation a porté sur l’analyse comparative des contours de feux calculés par le modèle avec ceux mesurés lors de deux brûlages dirigés, dont un réalisé en Thaïlande dans le cadre de cette thèse, et ceux mesurés lors du feu de Favone de 2009 en Corse et d'un feu de grande ampleur aux États-Unis. Les temps de calcul sont très inférieurs au temps réel. Le modèle a été ensuite étendu pour permettre une évaluation du risque incendie à l’interface forêt-habitat. Dans le cadre du projet TechForFire, porté par la société NOVELTIS, il a été enfin couplé aux différents modules de la chaîne opérationnelle. La chaîne complète a été validée sur le feu historique de Velaux de 2015. / This thesis work is focused on the development of a wildfire spread model and its integration into a decision-making tool for planning firefighting operations. The fire spread model is based on a network model to represent vegetation distribution on land and considers the main heat transfer mechanisms from burning to unburnt vegetation items (i.e. radiation from the flaming zone and embers, surface convection and wind-driven convection through the fuel bed, and radiative cooling from the heated fuel element to the environment). The effects of local conditions of wind, topography, and vegetation are included. To address the challenge of real-time fire spread simulations, the model is also extended in two ways. First, the Monte Carlo method is used in conjunction with a genetic algorithm to create a database of radiation view factors from the flame to the fuel surface for a wide variety of flame properties and environment conditions. Second, the front-tracking method is introduced in order to reduce the amount of data to store and handle during propagation. The fire spread model is validated against data from different fire scenarios, showing it is capable of capturing the trends observed in experiments in terms of rate of spread, and area and shape of the burn, with reduced computational resources. It is then extended to evaluate fire risk at the wildland fire interface. In the frame of the TechForFire project coordinated by the NOVELTIS company, the new version of the fire spread model is coupled with the other modules of the operational chain. Finally, data from the fire of Velaux in 2015 are used to evaluate the TechForFire solution.

The topic of this master’s thesis is design of fire fighting and rescue vehicle, more specifically wildland fire apparatus primarily intended for difficult terrain. The main aim of this design is to create functional object fulfilling ergonomic, technical, and aesthetic demands.