Electric field probes for quantitative moisture measurements in building materials

Conference · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5486728

Courville, G E; Hylton, J O; Murray, W P; Blalock, A; Remenyik, C J

Three novel capacitance techniques for making moisture measurements in insulated roof systems are being studied at the Oak Ridge National Laboratory (ORNL). These are designated as the ''Pin Probe,'' the ''Thermocouple Probe,'' and the ''Planar Probe.'' The Pin Probe, developed at the Massachusetts Institute of Technology (MIT), consists of two parallel lines of straight pins as the two probe electrodes. This is an intrusive probe that must be mounted within the system being tested. The Thermocouple Probe is also intrusive. Its use assumes that thermocouple junctions exist at known locations in the specimen for temperature measurements. The probe electronics allows high frequency capacitance measurements between thermocouples without interfering with their temperature measurement function. The third probe, the Planar Probe, is non-intrusive and consists of a series of equally spaced plate electrodes in a box that sits on the surface of the roof. These electrodes provide several independent electrical signals from overlapping depths within the roof system. An analysis procedure was developed to identify the electrical properties of successively deeper layers of material. Prototypes of each of these probes have been constructed and promising preliminary data are available. Probe calibration, circuit stability, and range of applicability are major outstanding issues that must still be addressed. 6 refs., 12 figs., 4 tabs.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5486728
• Report Number(s): CONF-871271-1; ON: DE88006415
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320107* -- Energy Conservation
Consumption
& Utilization-- Building Systems-- (1987-)
440300 -- Miscellaneous Instruments-- (-1989)
47 OTHER INSTRUMENTATION
BUILDINGS
CALIBRATION
CAPACITANCE
DESIGN
ELECTRIC IMPEDANCE
ELECTRICAL PROPERTIES
ELECTRONIC CIRCUITS
IMPEDANCE
MEASURING INSTRUMENTS
MOISTURE GAGES
PHYSICAL PROPERTIES
ROOFS
TESTING
THERMOCOUPLES