Caracterização de Barreiras Pára-Vapor e sua Aplicação

Abstract

Humidity is one of the main causes of buildings' pathologies, being of the largest importance the development of studies that allow a larger understanding of the associated phenomena, so that on can define qualitative and quantitative rules for the conception and execution of the building envelope, in regard to this problem. Condensation is an important form of humidity manifestation with pathological character. It can occur in the interior surface of the building components (surface condensation) or in the interior of the own elements (internal condensation). Internal condensation results of the vapor diffusion phenomenon and in this work the main aspects to attend on its simulation arw referred, namely Fick's theory of vapor diffusion and the Glaser model, of easy practical application. Vapor retarders are building components of great importance, in the way that they restrict vapor diffusion through the building elements, like walls, roofs and floors. In this study are presented the main parameters to attend in the choice and application of this type of materials. In the present work, we can also find the results of some tests that were made to determine the vapor permeability characteristics of several building materials that can be used as vapor retarders. These tests were taken over at the Building Physics Laboratory (LFC) of the Faculty of Engineering of the University of Porto (FEUP). Finally, are presented some design criteria for the buildings' envelope face to the vapor diffusion and internal condensation phenomena, which are referred in related bibliography. Key-Words: Internal condensation, vapor diffusion, vapor permeability, Glaser model, vapor retarders, design criteria.