STP779

    Moisture Migration in Fibrous Insulating Materials Under the Influence of a Thermal Gradient and Its Effect on Thermal Resistance

    Published: Jan 1982


      Format Pages Price  
    PDF Version (244K) 16 $25   ADD TO CART
    Complete Source PDF (4.8M) 16 $86   ADD TO CART


    Abstract

    The thermal conductivity of a high density mineral fiberboard has been experimentally determined as a function of water content, at ambient temperature. The measurements, performed on three different apparatus over a moisture range of 0 to 150 percent by weight, show that the temperature gradient causes a redistribution of moisture which affects the thermal conductivity. The results are strongly dependent on the experimental conditions (for example, the orientation of the specimen). The variation of thermal conductivity with respect to dry state may reach 10 percent for a moisture content of about 30 percent by weight. In practice, the main cause of moisture presence in fibrous insulating materials is adsorption. The quantities adsorbed at 90 percent relative humidity are of 2 percent or less (in mass). For this small amount of water the variation of thermal conductivity with respect to dry state is negligible. All the results are discussed with the present problems of standardization in mind. Of particular interest are the problems concerning the “corrected” values of thermal resistances or thermal conductivities of insulants “in use” (design λ value).

    Keywords:

    adsorption, condensation, fibrous material, glass fiber, guarded hot plate, heat flowmeter, heat transfer, porous material, thermal conductivity, standardization, moisture migration


    Author Information:

    Langlais, C
    Isover Saint-Gobain, Centre de Recherches Industrielles, Rantigny,

    Hyrien, M
    Isover Saint-Gobain, Centre de Recherches Industrielles, Rantigny,

    Klarsfeld, S
    Isover Saint-Gobain, Centre de Recherches Industrielles, Rantigny,


    Paper ID: STP38694S

    Committee/Subcommittee: E06.41

    DOI: 10.1520/STP38694S


    CrossRef ASTM International is a member of CrossRef.