Relating measured moisture of gypsum board to estimated water activity using moisture meters
| Autor: | Kazukiyo Kumagai, Janet M. Macher, Mark J. Mendell, Wenhao Chen, Rachel I. Adams |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Environmental Engineering
Gypsum Moisture Water activity Geography Planning and Development 0211 other engineering and technologies Soil science 02 engineering and technology Building and Construction 010501 environmental sciences engineering.material Principal factor 01 natural sciences Adverse health effect engineering Metre Environmental science Relative humidity 021108 energy 0105 earth and related environmental sciences Civil and Structural Engineering |
| Zdroj: | Building and Environment. 147:284-298 |
| ISSN: | 0360-1323 |
| DOI: | 10.1016/j.buildenv.2018.10.030 |
| Popis: | Dampness and mold in buildings are linked to multiple adverse health effects. The principal factor allowing microbial growth in a material is the water activity (aw), the amount of metabolically available water. To assess the practicality of a portable “aw sensor” that estimates aw by measuring equilibrium relative humidity (ERH) at a surface, we measured the time required, starting at typical room RH, to reach a stable ERH reading on gypsum board at an elevated aw supportive of microbial growth. To estimate aw with commonly used moisture meters, we compared multiple meters (two types: pinless or 2-pin) to each other and to the portable aw sensor, for several gypsum board configurations, at multiple targeted ERH conditions. The aw sensor response was too slow for practical use. Across board configurations (i.e., single or double layers, unpainted or painted, and moisture-resistant), relationships between moisture meter readings and estimated aw differed, as expected, between sorbing and desorbing conditions. Some pinless meters showed inadequate sensitivity to low moisture conditions. Unexpected irregularities in responses were seen, especially on painted board. We provide estimated ranges of moisture meter readings, for each meter and board configuration, corresponding with selected aw values potentially supportive of microbial growth. One or two meters showed most promise for use in estimating critical aw values, although with substantial caveats. The irregularities observed may limit the potential for estimating aw from moisture meter readings in real world applications, even with prior collection of the data needed across different meters, conditions, and building materials. |
| Databáze: | OpenAIRE |
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