STP1451: A Realistic Approach for Testing the Thermal Insulation Value of Closed-Cell Spray Polyurethane Foam Roof Insulation

    Sherman, M
    consultMORTinc., St. Petersburg, FL

    Mullally, W
    Dow Chemical Co., Joliet, IL

    Garcia, J
    Dow Chemical Co., Joliet, IL

    Dobrez-Flores, D
    Dow Chemical Co., Joliet, IL

    Pages: 8    Published: Jan 2003


    The thermal resistance characteristics of thicker closed-cell spray polyurethane foam insulation products appear to be understated when tested at one inch thickness as required in ASTM C1O29-96 [1]. This results in excessive and costlier foam thicknesses being prescribed to meet a specifier's R-value requirements than if full product thickness conditioning before full product thermal resistance testing had been specified.

    Confirmation of this concern was studied by the Building Envelope Committee of the Spray Polyurethane Foam Alliance, measuring full product thickness thermal resistances after the 180 days conditioning time. Three commercially marketed proprietary closed-cell spray polyurethane foam formulations containing HCFC 141b blowing agent were tested.

    All three formulations affirmed the concept of measuring full product thickness thermal resistance after time conditioning. Increasingly thicker spray polyurethane foam specimens retained more of their initial thermal resistance values after the standard 180 days of time conditioning before testing, than if thermal resistance values measured on one inch thick spray foam specimens multiplied by the full product thickness, were used for extrapolating these thicker product thermal resistances, as done with homogeneous thermal insulations.


    apparent thermal conductivity, apparent thermal resistance, full product thickness, HCFC 141b blowing agent, normalized R-value, roof insulation, spray polyurethane foam, time conditioning

    Paper ID: STP11449S

    Committee/Subcommittee: D08.06

    DOI: 10.1520/STP11449S

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