Samples of two mineral fiber/portland cement-based FRMs were obtained from a manufacturer. The samples were of nominal size 300 mm by 300 mm by 25 mm. Heat capacities, densities, and thermal conductivities of these materials had been previously determined by various laboratories.2, 6, 7 Here, the two materials shall be designated as FRM A and FRM B. The room temperature densities of FRM A and FRM B were measured to be 314 kg/m3 and 237 kg/m3, respectively.6 The heat capacity and mass loss measurements versus temperature for the two materials are provided in Figures 4 and 5. The testing laboratory reported their heat capacity values to be normally within ± 5 %.6 For each test run in the furnace, two panels of dimensions 152 mm by 152 mm by 25 mm were cut from the larger panels to use in the sandwich specimen configuration. The initial mass of each specimen was measured and recorded. The specimens of the FRMs were not preconditioned prior to evaluation in the box furnace.
Figure 4- Measured values6 and fitted curves for heat capacities vs. temperature of the two FRMs. Fitted curves are of the form cp = A + BT + Cln(T) with T in degrees K.
Figure 5- Values6 measured according to ASTM E11311 and fitted curves for mass loss vs. temperature of the two FRMs. Fitted curves are of the form M = A + BT + Cln(T) with T in degrees K.
A fumed-silica insulation board with a low thermal conductivity (≈0.02 W/m·K) was used both as thermal insulation in the sandwich configuration and as a non-reactive "reference" material for evaluating the experimental setup. The board is available as NIST Standard Reference Material 1449 (http://ts.nist.gov/) and its room temperature8 and high temperature9 thermal conductivities have both been previously measured by NIST. Specimens8 were obtained in panels having nominal dimensions of 600 mm by 600 mm by 25 mm with a nominal bulk density of about 310 kg/m3. For the purposes of this study, smaller sections were carefully cut as needed from one large panel using a hand saw. All samples were pre-conditioned overnight in a 100 ºC oven prior to being used as insulation or test specimens in the box furnace setup. The panels had been previously heat treated at 650 ºC for 8 h by the manufacturer.8 The heat capacity of the fumed-silica board as a function of temperature was measured using a differential scanning calorimeter (DSC) and the ASTM E1269 standard technique1 and determined to be on the order of (1000 ± 100) J/(kg·K), in good agreement with the limited data available in the literature for similar materials currently in production.10, 11