A Conceptual System of Moisture Performance Analysis
Pages: 10 Published: Jan 2009
IN A MANUAL SUCH AS THIS ONE, INDIVIDUAL ASpects of moisture control are discussed in separate, discipline-oriented chapters, even though such a treatment of the subject matter does not allow the integration of these various aspects into a comprehensive strategy of moisture control. Yet, there is a need for consolidating the multitude of findings of the research and field studies in the rapidly developing science of environmental control in buildings. This chapter attempts to fill this need by introducing a conceptual system of moisture performance analysis. The following chapter, added in the second edition of this manual, will continue the topic even further, leading the reader towards the development of methods for assessment of moisture-originated damage. Performance of whole buildings as it depends on building components, e.g., external envelope, mechanical and electrical systems, and operational conditions (defined by climate and occupancy of the building), must also be related to the selection of materials forming the components of the building system. In this process, the materials are selected on the basis of structural and environmental control considerations . Yet, while the structural design is well defined, this is not the case with the environmental control process. In the worst case, the environmental design is based on experience gained by the designer in the trial and error process. Heat, air, and moisture transport across a building envelope are inseparable phenomena. Each influences the other and is influenced by all the materials contained within the building envelope. Often we simplify the process of design by relating control of each phenomenon to a particular material or component. The thermal insulation, for example, is perceived to control heat transfer and the air barrier to control air leakage (Table 1). Likewise, the rain screen and vapor barrier eliminate ingress of moisture into the system.
Paper ID: MNL11567M
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