ASTM C1045-19
Standard Practice for Calculating Thermal Transmission Properties Under Steady-State Conditions

Standard No.

ASTM C1045-19

Release Date

2019

Published By

American Society for Testing and Materials (ASTM)

Latest

ASTM C1045-19

Scope

1.1 This practice provides the user with a uniform procedure for calculating the thermal transmission properties of a material or system from data generated by steady state, one dimensional test methods used to determine heat flux and surface temperatures. This practice is intended to eliminate the need for similar calculation sections in Test Methods C177, C335, C518, C1033, C1114 and C1363 and Practices C1043 and C1044 by permitting use of these standard calculation forms by reference. 1.2 The thermal transmission properties described include: thermal conductance, thermal resistance, apparent thermal conductivity, apparent thermal resistivity, surface conductance, surface resistance, and overall thermal resistance or transmittance. 1.3 This practice provides the method for developing the apparent thermal conductivity as a function of temperature relationship for a specimen from data generated by standard test methods at small or large temperature differences. This relationship can be used to characterize material for comparison to material specifications and for use in calculation programs such as Practice C680. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 This practice includes a discussion of the definitions and underlying assumptions for the calculation of thermal transmission properties. Tests to detect deviations from these assumptions are described. This practice also considers the complicating effects of uncertainties due to the measurement processes and material variability. See Section 7. 1.6 This practice is not intended to cover all possible aspects of thermal properties data base development. For new materials, the user should investigate the variations in thermal properties seen in similar materials. The information contained in Section 7, the Appendix and the technical papers listed in the References section of this practice may be helpful in determining whether the material under study has thermal properties that can be described by equations using this practice. Some examples where this method has limited application include: (1) the onset of convection in insulation as described in Reference (1); (2) while a phase change is taking place in one of the insulation components causing an unsteady-state condition; and (3) the influence of heat flow direction and temperature difference changes for reflective insulations. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

ASTM C1045-19 Referenced Document

• ASTM C1033 Standard Test Method for Steady-State Heat Transfer Properties of Pipe Insulation Installed Vertically (Withdrawn 2003)
• ASTM C1043 Standard Practice for Guarded-Hot-Plate Design Using Circular Line-Heat Sources
• ASTM C1044 Standard Practice for Using a Guarded-Hot-Plate Apparatus or Thin-Heater Apparatus in the Single-Sided Mode
• ASTM C1058 Standard Practice for Selecting Temperatures for Evaluating and Reporting Thermal Properties of Thermal Insulation
• ASTM C1114 Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Thin-Heater Apparatus
• ASTM C1199 Standard Test Method for Measuring the Steady-State Thermal Transmittance of Fenestration Systems Using Hot Box Methods*， 2022-03-01 Update
• ASTM C1363 Standard Test Method for the Thermal Performance of Building Assemblies by Means of a Hot Box Apparatus
• ASTM C168 Standard Terminology Relating to Thermal Insulation*， 2022-05-01 Update
• ASTM C177 Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus
• ASTM C335 Standard Test Method for Steady-State Heat Transfer Properties of Horizontal Pipe Insulation
• ASTM C518 Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus
• ASTM C680 Standard Practice for Determination of Heat Gain or Loss and the Surface Temperatures of Insulated Pipe and Equipment Systems by the Use of a Computer Program
• ASTM E122 Standard Practice for Calculating Sample Size to Estimate, With a Specified Tolerable Error, the Average for Characteristic of a Lot or Process

ASTM C1045-19 history

• 2019 ASTM C1045-19 Standard Practice for Calculating Thermal Transmission Properties Under Steady-State Conditions
• 2007 ASTM C1045-07(2013) Standard Practice for Calculating Thermal Transmission Properties Under Steady-State Conditions
• 2007 ASTM C1045-07 Standard Practice for Calculating Thermal Transmission Properties Under Steady-State Conditions
• 2001 ASTM C1045-01 Standard Practice for Calculating Thermal Transmission Properties Under Steady-State Conditions
• 1997 ASTM C1045-97 Standard Practice for Calculating Thermal Transmission Properties Under Steady-State Conditions