Análise dos impactos da transferência de umidade no comportamento higrotérmico das superfícies internas de paredes externas de edificação histórica do séc. XIX

Abstract

Hygrothermal performance has been an important issue in recent years with regard to the rehabilitation of historic buildings. In Brazil there is a lack of specific standards for this type of building and on issues of performance and preservation of historical heritage. Problems with humidity on the surface of internal walls in buildings offer the risk of condensation, providing favorable conditions for pathologies such as the formation of filamentous fungi, thus compromising the health of users. In this way, the objective of the study was to analyze the behavior of moisture transport on the internal surfaces of the external walls and the risks of internal superficial condensation and formation of filamentous fungi that a historic building can suffer when exposed to the climatic and environmental conditions of temperature and humidity. in bioclimatic zone 2. For the method, the typology of the historic building was defined, Casarão 02, located in the historic center of the city of Pelotas, RS, a region characterized by a humid subtropical climate, with hot summers and cold winters and a high level of humidity on air during the year, and carried out simulations with two softwares. The simulations with the Energy Plus software made it possible to determine the natural ventilation of environments with two different algorithms: the transfer of heat conduction and the transfer of heat and humidity, as well as comparing their behavior through the results. By adopting the WUFI Pro 6.6 software, it became possible to obtain data to analyze the hygrothermal performance of the historic building, as well as the risks of condensation and the formation of filamentous fungi that compromise the construction system and indoor air quality. Construction systems with and without interior and exterior vapor barrier were evaluated, for three solar orientations and two types of climate conditions, natural and artificial. The data for simulations were about the thickness of the layers of the original wall without and with vapor barrier, thermal and hygrothermal properties of the materials, local climate file, use of space occupation, lighting and ventilation. The simulations were carried out for a period of three years and the results of the last year were evaluated, observing the three months of winter and the three months of summer. The results of the internal surface temperature of the CTF-algorithm is higher than that of the HAMT-algorithm, as for the total moisture contents were high for all conditions of construction and ventilation systems, not showing drying on the walls. Of the three orientations, the South one presents the worst result due to solar radiation. When comparing the two algorithms, the results were approximated As for the risk of steam condensation and the risk of forming filamentous fungi, the artificially conditioned ventilation systems, using an internal and external vapor barrier, showed the best results with a temperature above the dew point in the winter months and little or no mold growth on interior surfaces of historic building studied.