WORKSHOP HELD ON MOISTURE SENSORS FOR BUILDING ENVELOPES.A workshop to discuss moisture sensing in building envelopes was held at NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. in July 2000. Researchers and industry representatives met to discuss many of the problems that exist in determining the moisture content of building materials Building materials used in the construction industry to create . These categories of materials and products are used by and construction project managers to specify the materials and methods used for . and to discuss new technologies that may improve those measurements. Moisture in homes and buildings lies at the heart of many problems that afflict af·flict tr.v. af·flict·ed, af·flict·ing, af·flicts To inflict grievous physical or mental suffering on. [Middle English afflighten, from afflight, buildings. Mold, pests, allergens, structural damage, and unwanted heat loss arise when unwanted water accumulates in the building envelope. While the modeling of moisture transport has advanced the state of knowledge in controlling these problems, the sensing technology for measuring the in-situ moisture content in building materials has lagged. Several presenters with extensive field and laboratory experience shared their success and failures in measuring moisture. These presentations indicated that the technol-ogy is sorely in need of refinement to provide sensors with simpler installation, more accurate calibrations, and less drift. It also was determined that a need exists for both moisture content measurements in the building materials (for model verification and predictions of rot) and relative humidity relative humidity n. The ratio of the amount of water vapor in the air at a specific temperature to the maximum amount that the air could hold at that temperature, expressed as a percentage. measurements at the surface of the materials (as an indicator of mold and mildew mildew, name for certain fungi and protists, for the diseases they cause in various crops, and for the discoloration (and sometimes the weakening and disintegration) they cause in such materials as leather, fabrics, and paper. growth). Several presentations were made on new technologies that potentially could be used for these applications such as infrared sensors, nuclear magnetic resonance nuclear magnetic resonance: see magnetic resonance. nuclear magnetic resonance (NMR) Selective absorption of very high-frequency radio waves by certain atomic nuclei subjected to a strong stationary magnetic field. , fiber optic sensors, and algorithms that can be incorporated in sensors to predict the onset of damage. Information from the workshop will enable NIST to target its research efforts on moisture sensors. |
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