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Hygrothermal Property Measurements

On this page you'll find information about the Building Technologies Program envelope materials R&D project on hygrothermal property measurements, including objectives, benefits, and approach.

Objectives

Develop a world-class laboratory capability for measurement of the hygrothermal properties of building materials, required for modeling moisture transport in building envelopes. Such property values are needed as inputs to moisture simulation models and provide the link between the models and large-scale experiments on moisture transfer in building envelope components.

Benefits

Greater control of moisture problems, resulting in enhanced energy efficiency, improved indoor air quality, and reduced structural decay.

Approach

Properties to be measured include the moisture capacity as a function of temperature and relative humidity (sorption isotherms in the hygroscopic range of less than about 90% RH and suction isotherm in the capillary range of greater than about 90% RH); water vapor permeability; liquid diffusivity; liquid uptake; and two-dimensional distributions of moisture.