PBD WUI-specific guidelines; initial draft

Postprint (updated version

Comparative analysis of BLEVE mechanical energy and overpressure modelling

The mechanical effects of a BLEVE are overpressure and ejection of fragments. Although fragments reach much longer distances, peak overpressure can be very strong over a certain area. Diverse authors have proposed methodologies for the estimation of the explosion energy and peak overpressure from these type of explosions, based on different thermodynamic and physical assumptions. Here these methodologies are commented and compared. Their predictions, which show an important scattering, are checked by comparison with two sets of experimental data taken from the literature. The results obtained indicate that none of the models take into account Reid’s theory. The models based on ideal gas behaviour and constant volume energy addition, isentropic expansion and isothermal expansion give quite conservative (i.e., high) values of both energy released and overpressure, while those assuming real gas behaviour and adiabatic irreversible expansion give lower values, much closer to the real/experimental ones. The diverse uncertainty factors affecting the prediction of peak overpressure are also commented.Postprint (published version

Technical Note TN 2.4. Fuel sampling, tree ignition and burning tests in ADAI facilities

In this document, the followed methodology to characterize several natural fuels (trees of Cupressus arizonica, Cupressocyparis leylandii, Prunus laurocerasus and Thuja occidentalis) is presented. Also, the ignition method and the equipment used to monitor the burning of these fuels in two different configurations are described. These activities were performed in ADAI facilities (Lousa, Portugal).Preprin

Short-term fire front spread prediction using inverse modelling and airborne infrared images

A wildfire forecasting tool capable of estimating the fire perimeter position sufficiently in advance of the actual fire arrival will assist firefighting operations and optimise available resources. However, owing to limited knowledge of fire event characteristics (e.g. fuel distribution and characteristics, weather variability) and the short time available to deliver a forecast, most of the current models only provide a rough approximation of the forthcoming fire positions and dynamics. The problem can be tackled by coupling data assimilation and inverse modelling techniques. We present an inverse modelling-based algorithm that uses infrared airborne images to forecast short-term wildfire dynamics with a positive lead time. The algorithm is applied to two real-scale mallee-heath shrubland fire experiments, of 9 and 25 ha, successfully forecasting the fire perimeter shape and position in the short term. Forecast dependency on the assimilation windows is explored to prepare the system to meet real scenario constraints. It is envisaged the system will be applied at larger time and space scales.Peer ReviewedPostprint (author's final draft

Modelling Temperature Evolution in Equipment Engulfed in a Pool-fire

A method is presented to calculate the incident radiant heat ßux and the temperatures reached on any point of a tank surface when this tank is engulfed in a pool-Þre during the Þre transitory state (developing phase). ¹he method used to calculate the radiant heat ßux on the cylinder is based on a three-dimensional formulation and uses the deÞnition of a surface to establish the ßame contour (according to a rectangular pool) taking into account the temperature changes with height and time. ¹he results are compared to experimental data obtained with large scale pool-Þres of hexane and kerosene, and show a good agreement. Finally, some conclusions are derived.Peer ReviewedPostprint (published version

Efectivitat dels tractaments de combustible en la reducció del risc de propagació d'incendi

Els programes de simulació han estat àmpliament utilitzats en l'estudi del comportament dels incendis forestals i concretament en l'avaluació de l'efectivitat dels tractaments de combustible. Aquests tractaments, tals com les cremes prescrites o les aclarides, provoquen la modificació de l'estructura de les masses forestals i, per tant, de certs paràmetres bàsics del combustible que condicionaran el comportament d'un eventual incendi. Els diferents estudis que han avaluat els tractaments de combustible en la reducció del risc de propagació d'incendi evidencien la seva efectivitat. Tanmateix, aquests estudis no estan en consonància sobre quin tipus de tractament és el més efectiu. En aquest treball s'inclou una revisió bibliogràfica sobre l'avaluació de l'efectivitat dels tractaments de combustible, detallant en profunditat la metodologia utilitzada i els resultats obtinguts.Efectividad de los tratamientos de combustible en la reducción del riesgo de propagación de incendio. Los programas de simulación han sido ampliamente utilizados en el estudio del comportamiento de los incendios forestales y concretamente en la evaluación de la efectividad de los tratamientos de combustible. Estos tratamientos, tales como las quemas prescritas o clareo provocan la modificación de la estructura de las masas forestales y, por lo tanto, de ciertos parámetros básicos del combustible que condicionarán el comportamiento de un eventual incendio. Los diferentes estudios que han evaluado los tratamientos de combustible en la reducción del riesgo de propagación de incendio evidencian su efectividad. Aun así, estos estudios no están en consonancia sobre qué tipo de tratamiento es el más efectivo. En este trabajo se incluye una revisión bibliográfica sobre la evaluación de la efectividad de los tratamientos de combustible detallando en profundidad la metodología utilizada y los resultados obtenidos.Fuel treatment effectiveness in reducing the fire risk propagation. Simulation tools have been widely used in evaluating the effectiveness of fuel treatments on wildfire behavior. Fuel treatments, such as prescribed burning or thinning, lead to changes in the forest structure and therefore modify certain basic parameters that may influence the fuel?s behavior in a potential fire. Fuel treatments have been shown to be effective at mitigating fire damages in various studies. However, these studies are not consistent regarding what treatment is the most efficient. This paper reviews the state of the art on the evaluation of the effectiveness of fuel treatments paying special attention to the methodology used to assess them and the results obtained

Computing wildfire behaviour metrics from CFD simulation data

In this article, we demonstrate a new post-processing methodology which can be used to analyse CFD wildfire simulation outputs in a model-independent manner. CFD models produce a great deal of quantitative output but require additional post-processing to calculate commonly used wildfire behaviour metrics. Such post-processing has so far been model specific. Our method takes advantage of the 3D renderings that are a common output from such models and provides a means of calculating important fire metrics such as rate of spread and flame height using image processing techniques. This approach can be applied similarly to different models and to real world fire behaviour datasets, thus providing a new framework for model validation. Furthermore, obtained information is not limited to average values over the complete domain but spatially and temporally explicit metric distributions are provided. This feature supports posterior statistical analyses, ultimately contributing to more detailed and rigorous fire behaviour studies.Peer ReviewedPostprint (published version

WUI state of the art and regulatory needs in Europe

The document summarizes the state of the art of the regulationsrelevant to WUI in Europe, providing an organized set of references to the specific regulatory documents. It is focused on three main relevant topics: i) fuel-reduced fringes; ii) Building codes and standards; iii)Wildland-Industrial Interface. Current regulations are analysed and compared, leading to the identification of important needs and limitations of the current European regulatory frameworkPreprin

A new procedure to estimate BLEVE overpressure

Several methodologies, based on different thermodynamic assumptions and requiring substance properties and thermodynamic data, have been proposed in the literature for the prediction of the mechanical energy released by a Boiling Liquid Expanding Vapour Explosion (BLEVE) and the associated overpressure. A new method, simple and easy to use, is presented which only requires the vessel filling degree and the temperature at failure as input variables to estimate this energy. The polynomial approach has been used to obtain the equation corresponding to the diverse substances most commonly involved in these explosions. The comparison of the predicted values with experimental data shows a good agreement.Peer ReviewedPostprint (author's final draft

How to qualify the vegetation in public squares to help the management of urban ecosystem services?

We adopted procedures to analyze the floristic composition of public squares in Irati, Paraná, in order to diversify the provision of methods to generate information for public management. We found that describing the ratio of taxa may not be efficient for presenting problems regarding species diversification. Species diversity analysis should be divided into tree quantity and canopy area to determine the benefits that could be lost from removing exotic species. Using the procedure that considers crown area is more effective for estimating the cover value of the species. The diameter distribution, total height, and crown area curves can help management decisions about new plantings and prioritize risk assessment. The results of spatial indices can complement the information about data distribution