In-Situ Measurement of the Moisture Content of Building Materials Using Ultra-Wideband Radio Waves.
In-Situ Measurement of the Moisture Content of Building
Materials Using Ultra-Wideband Radio Waves.
(162 K)
Healy, W. M.
NRCC-46103;
Research in Building Physics and Building Engineering.
Building Physics Conference, 3rd International.
Proceedings. August 27-31, 2006, Montreal, Canada,
Taylor and Francis/Balkema, Leiden, Netherlands,
Editor(s), 173-180 pp, 2006.
Keywords:
building materials; moisture content; radio waves;
transmission; tests; strand board; plywood; gypsum
board; wood; data analysis; sensitivity; experiments
Abstract:
A study was carried out to determine the feasibility of
commercial, off-the-shelf, and potentially low-cost
ultra-wideband radio hardware to serve as a measurement
tool for the moisture content of building materials. The
study examined both reflections from and transmission
through an envelope assembly when pulses with a center
frequency of 4.7 GHz were emitted towards the materials.
The reflected energy was found to be the best measure of
moisture content. Tests on oriented strand board,
plywood, and gypsum board showed that a linear trend was
found between the reflected energy and moisture content
of the two wood products, but the range of moisture
contents in the gypsum boards was insufficient to have
any appreciable effect on the signal returned. The
ability to independently measure the moisture content of
several layers with a single scan was also examined, but
the data suggest that more work is needed to accomplish
this goal.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899