Avaliação do Desempenho Higrotérmico de Paredes em Regime Dinâmico em Função do Clima

Abstract

The humidity on the façades of the buildings provokes in a slow, invisible and silent way degradations on the construction materials. Originated mostly by the incidence of rain and condensations on the surface, it allows the ideal conditions for the growth of microorganisms (seaweeds and fungus). The development of these microorganisms is deeply connected to the level of humidity on the surface that results from the humidification by the incidence of the rain on the façade, of the humidification by superficial condensation and the process of drying. These three parameters are influenced by the orientation that modifies the quantity of atmospheric and solar radiation incident on the façade, by the velocity and direction of the wind and by the physical properties of the materials that constitute the element (thermal resistance, solar absorption, liquid water absorption, emissivity, external thermal inertia, etc). In that sense, to evaluate the occurrence of condensations and the level of humidity on the surface of the façades, a study was taken. This way, with recourse to numerical simulation by using the automatic programme of calculation "WUFI Pro 4.2" developed by "Fraunhofer Institut für Bauphysik" in order to evaluate how the kind of constructive solution, the location, orientation, the color of the façade and the thickness of the thermal isolation influence the condensations and the levels of humidity on the surface and consequently the development of microorganisms. It was considered relevant to include in this work, to a better understanding and study of the higrothermal behavior of the buildings, a chapter dedicated to the terminology currently used in the studies about higrothermics. At the end of this study, in a way to allow a quick interpretation of the obtained results, it is presented a chart that through a gradation of colors allows a global perception of the risk of microorganisms' development in the different solutions studied. KEYWORDS: Façades, Higrothermal performance, Terminology of the higrothermal domain, Numerical simulation, Microorganisms development (seaweeds and fungus).