ASTM C351-92b(1999)e1

Mean specific heat is an essential property of a thermal insulating material when the latter is used under conditions of unsteady or transient heat flow. It is a part of the parameter, thermal diffusivity, which governs the rate of temperature diffusion through insulation. It is a basic thermodynamic property of all substances, the value of which depends upon chemical composition and temperature.

Note 1—Specific heat of insulations, as measured by this test method, using small specimens of a multi-component composite or of a low-density product that has to be highly compressed, may not be directly applicable for use in calculations involving transient thermal response. The applicability of the results will depend upon a system being analyzed, the desired accuracy, and the relative amounts, and specific heats of the various solid or fluid components, or both, of the thermal insulation.

1.1 This test method covers the determination of mean specific heat of thermal insulating materials. The materials must be essentially homogeneous and composed of matter in the solid state.

1.2 This test method employs the classical method of mixtures. This provides procedures and apparatus simpler than those generally used in scientific calorimetry, an accuracy that is adequate for most thermal insulating purposes, and a degree of precision that is reproducible by laboratory technicians of average skill. While this test method was developed for testing thermal insulations, it is easily adaptable to measuring the specific heat of other materials.

1.3 The test procedure provides for a mean temperature of approximately 60°C (100 to 20°C temperature range), using water as the calorimetric fluid. By substituting other calorimetric fluids the temperature range may be changed as desired.

1.4 The values stated in SI units are to be regarded as the standard.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.