Isotherm

Isotherm is the relation between moisture content versus relative humidity at a given temperature. It is also called: soption isotherm. Hysteresis exists for many material, due to the difference between wetting and drying of materials.

Standards:

ASTM Test Method C 1498

drying temperatures ˇ°a) for materials which do not change either structure or dimensions at 105ˇăC, for example, some mineral materials, use 105 ˇŔ 4ˇăC; b) for materials in which structural or dimensional changes occur between 70ˇăC and 105ˇăC,

for example for some cellular plastics, use 70 ˇŔ 4ˇăC; c) for materials in which elevated temperatures bring about chemical or physical changes, for example crystalline water in gypsum or blowing agent solubility in some cellular plastics, use 40 ˇŔ 2ˇăC.ˇ±

complete when five successive daily weighings produce mass changes of less than 0.1%

ISO 12571

Hansen, K. K., 1986, Sorption isotherms: a catalog and a data base kept a database of more than 100 materials.

Isotherm, among other hygrothermal properties, were also derived from pore distributions. (? Hedenblad, G., 1996, Moisture properties of some modern building materials)

Wood movement as it effects joinery

Effect of moisture, isothermal, shrinkage of various wood specias

under periodical relative humidity

A new algorithm to calculate the isothermal moisture penetration for periodically varying relative humidity at the boundary, by Arfvidsson, J., 1999

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Analysis of selected water absorption coefficient measurements, by Bomberg, M., Pazera, M., Plagge, R., 2005

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Isothermal moisture properties of wood-cementitious composites, by Bouguerra, A., Sallee, H., Barquin, F., Dheilly, R. M. and Queneudec, M., 1999

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Measurement of the moisture storage capacity using sorption balance and pressure extractors, by Janz, M., Johannesson , B. F., 2001

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Moisture diffusivity of building materials from water absorption measurements, by Kumaran, M. K., 1999

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Moisture properties of some modern building materials, by Hedenblad, G., 1996

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Moisture storage and non-isothermal transport properties of common building materials, by Dahl, S. D., Kuehn, T. H., Ramsey, J. W. and Yang, C., 1996

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Restrictions on the rate of absorption when evaluating sorption isotherms obtained using a micro-calorimetric technique, by Johannesson, B., 2001

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Retarded sorption in wood. experimental study, analyses and modelling, by H?kansson, 1998

a catalog and a data base

Sorption isotherms: a catalog and a data base, by Hansen, K. K., 1996

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Test of Four Different Experimental Methods to Determine Sorption Isotherms, by Johannesson, B. and Janz, M., 2002

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Transport and sorption phenomena in concrete and other porous media, by Johannesson, B., 2000