ASTM C1058-97

1.1 This practice covers standard mean temperatures for reporting thermal properties of thermal insulations, products, and materials, and of related systems and components, both insulated and uninsulated.

1.2 Thermal properties may be determined as a function of temperature by standard test methods. (Test Methods C177, C201, C236, C335, C518, C745, C976, C1114, Guide C653, and Practice C687, all in combination with Practice C1045.)

1.3 This practice recommends standard temperature conditions for use in testing and evaluating thermal properties as a function of temperature by standard test methods.

1.4 General applications of thermal insulations include:

1.4.1 building envelopes,

1.4.2 mechanical systems or processes, and building and industrial insulations.

1.5 The mean test temperatures to measure thermal properties for the two applications shall be selected from those listed in Table 1. It is recommended that thermal properties be reported at mean temperatures that span at least 80% of the intended end-use temperature range. The temperature differences for any chosen mean temperature will depend upon both the thermal insulation application (see appropriate materials specification), the method of evaluation, and the limitations of an apparatus. Temperature differences or relevant temperature conditions required by ASTM material specifications shall take parecedence over those recommended in this practice.

1.5.1 Standard temperatures are presented for conditions where both surfaces are exposed to fixed ambient temperatures that are typical for testing building constructions, both insulated and uninsulated (Table 2).

1.5.2 Standard temperatures are presented for conditions where the temperatures of the two surfaces are fixed and surface coefficients are not considered (Table 2 or Table 3).

1.5.3 For conditions where the temperature of only one surface is fixed with the other exposed to fixed ambient temperature, use the mean temperatures of Table 1.

1.6 The values given in SI units are to be regarded as the standard. Approximate inch-pound units are provided in the tables.

1.7 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.