|
Hygrothermal Property Measurements
|
introduction
The program for Hygrothermal Property
Measurements seeks to measure the properties of moisture transfer through laboratory
research. The data obtained will help us to understand the combined moisture and
thermal transfer, thus enabling us to develop strategies for proper moisture control in
buildings.
issues
Moisture transfer through building envelopes
affects more than the energy efficiency of the building. It also influences the
building’s durability and indoor air quality, and the health and safety of the
occupants. Moisture damage to the exterior envelopes of numerous buildings has been
widely publicized in the past few years. Moisture control is key to the development
of both energy efficient and durable buildings. Proper moisture control design
requires complex mathematical models of the dynamics of moisture transfer in
buildings. Because material properties may age at different rates and thermal and
moisture transfer affects the long-term performance of most construction materials, a
thorough knowledge of the hygrothermal properties of the constituent materials and
assemblies is needed.
objectives
|
Develop laboratory facilities for measurement
of the hygrothermal properties of building materials |
|
|
Develop testing methods and standards
|
|
|
Support modeling activities by supplying needed
material characterization of hygrothermal material properties and durability
attributes of materials |
research
For several years, moisture transfer in building envelope systems,
especially roofs, has been studied. This research has involved experiments
in the Large Scale Climate Simulator, outdoor tests, and simulations using
the
MOIST,
WUFI, and
MATCH computer
programs. In order to run these programs, input data are required on
the hygrothermal properties of the specific materials used in construction
of the test sections.
A world-class laboratory capability for measurement of the hygrothermal properties
of building materials is being set up. Properties to be measured include
moisture capacity in both the hygroscopic (low moisture content) and capillary
(high moisture content) regimes, water vapor permeability, liquid diffusivity,
liquid uptake, two-dimensional distributions of moisture using nuclear magnetic
resonance or gamma-ray methods, thermal conductivity, specific heat, and air-flow
permeability. The dependence of these properties are factors such as temperature
and relative humidity or moisture content will be determined, and a database of
material properties will be created and published.
|
|
|
|
| RESEARCH PROGRAM MENU SELECTIONS
|
)
)
