Resumen de Contribucio a l'estudi de l'efectivitat dels retardants a llarg termini aplicats als tallafocs quimics en la lluita contra incendis forestals
Forest fires not only devastate the wildland, but also have an effect on the economic and social systems. Due to the climate conditions, European Mediterranean countries are prone to suffering them. Among them, Portugal and Spain are heading the list in number of fires and area burned in the last 24 years. In addition, it has been detected the increase of the large forest fires in the last decades, this is caused by the lack of forest management for the leaving of country area.
Large wildland fires spread out of control and their extinction requires a great number of crews. Therefore, the resources have to be optimized and apply effectively the fire-extinguishers and retardants agents. These substances reduce inflammability and combustibility of the material that have impregnated. One type of these fire retardants are the long term ones, which applied for the construction of chemical firebreak during indirect attack, give new chances to the extinction techniques.
The objective of this thesis is focused on the contribution to the improvement knowledge of long-term forest fire retardants. On this subject, it has been studied the changes, in relation to the fire retardant applied, in the fire behaviour parameters and analyzed the influence of determinant factors on retardant effectiveness.
In order to achieve this objective, a series of trials have been executed in Barcelona's (UPC) and Portugal's (Coimbra-ADAI) facilities, using durum and hard wheat strew as fuels, respectively. In combustion table located in Barcelona the effects of the mixtures on the rate of fire spread and weight loss, the distribution of surface fuel bed temperatures, the heat flux by radiation and the irradiation have been studied. In Portugal's installation the rate of fire spread and weight loss using hard wheat strew were studied comparing the results with the obtained ones in Barcelona, also topography (slope and canyon configuration) and wind effects on the capacity of these mixtures in
