ASTM C177-19
Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus

Standard No.

ASTM C177-19

Release Date

2019

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM C177-19e1

Latest

ASTM C177-19e1

Scope

1.1 This test method establishes the criteria for the laboratory measurement of the steady-state heat flux through flat, homogeneous specimen(s) when their surfaces are in contact with solid, parallel boundaries held at constant temperatures using the guarded-hot-plate apparatus. 1.2 The test apparatus designed for this purpose is known as a guarded-hot-plate apparatus and is a primary (or absolute) method. This test method is comparable, but not identical, to ISO 8302. 1.3 This test method sets forth the general design requirements necessary to construct and operate a satisfactory guarded-hot-plate apparatus. It covers a wide variety of apparatus constructions, test conditions, and operating conditions. Detailed designs conforming to this test method are not given but must be developed within the constraints of the general requirements. Examples of analysis tools, concepts and procedures used in the design, construction, calibration and operation of a guarded-hot-plate apparatus are given in Refs (1-41).2 1.4 This test method encompasses both the single-sided and the double-sided modes of measurement. Both distributed and line source guarded heating plate designs are permitted. The user should consult the standard practices on the single-sided mode of operation, Practice C1044, and on the line source apparatus, Practice C1043, for further details on these heater designs. 1.5 The guarded-hot-plate apparatus can be operated with either vertical or horizontal heat flow. The user is cautioned however, since the test results from the two orientations may be different if convective heat flow occurs within the specimens. 1.6 Although no definitive upper limit can be given for the magnitude of specimen conductance that is measurable on a guarded-hot-plate, for practical reasons the specimen conductance should be less than 16 W/(m2 K). 1.7 This test method is applicable to the measurement of a wide variety of specimens, ranging from opaque solids to porous or transparent materials, and a wide range of environmental conditions including measurements conducted at extremes of temperature and with various gases and pressures. 1.8 Inhomogeneities normal to the heat flux direction, such as layered structures, can be successfully evaluated using this test method. However, testing specimens with inhomogeneities in the heat flux direction, such as an insulation system with thermal bridges, can yield results that are location specific and shall not be attempted with this type of apparatus. See Test Method C1363 for guidance in testing these systems. 1.9 Calculations of thermal transmission properties based upon measurements using this method shall be performed in conformance with Practice C1045. 1.10 In order to ensure the level of precision and accuracy expected, persons applying this standard must possess a knowledge of the requirements of thermal measurements and testing practice and of the practical application of heat transfer theory relating to thermal insulation materials and systems. Detailed operating procedures, including design schematics and electrical drawings, should be available for each apparatus to ensure that tests are in accordance with this test method. In addition, automated data collecting and handling systems connected to the apparatus must be verified as to their accuracy. This can be done by calibration and inputting data sets, which have known results associated with them, into computer programs. 1.11 It is not practical for a test method of this type to establish details of design and construction and the procedures to cover all contingencies that might offer difficulties to a person without technical knowledge concerning theory of heat flow, temperature measurements and general testing practices. The user may also find it necessary, when repairing or 1 This test method is under the jurisdiction of ASTM Committee C16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal Measurement. Current edition approved Jan. 1, 2019. Published January 2019. Originally approved in 1942. Last previous edition approved in 2013 as C177 – 13. DOI: 10.1520/C0177-19. 2 The boldface numbers given in parentheses refer to the list of references at the end of this standard. Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States 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. 1 modifying the apparatus, to become a designer or builder, or both, on whom the demands for fundamental understanding and careful experimental technique are even greater. Standardization of this test method is not intended to restrict in any way the future development of new or improved apparatus or procedures. 1.12 This test method does not specify all details necessary for the operation of the apparatus. Decisions on sampling, specimen selection, preconditioning, specimen mounting and positioning, the choice of test conditions, and the evaluation of test data shall follow applicable ASTM Test Methods, Guides, Practices or Product Specifications or governmental regulations. If no applicable standard exists, sound engineering judgment that reflects accepted heat transfer principles must be used and documented. 1.13 This test method allows a wide range of apparatus design and design accuracy to be used in order to satisfy the requirements of specific measurement problems. Compliance with this test method requires a statement of the uncertainty of each reported variable in the report. A discussion of the significant error factors involved is included. 1.14 Major sections within this test method are arranged as follows: Section Section Scope 1 Referenced Documents 2 Terminology 3 Summary of Test Method 4 Significance and Use 5 Apparatus 6 Specimen Preparation and Conditioning 7 Procedure 8 Calculation of Results 9 Report 10 Precision and Bias 11 Keywords 12 Figures General Arrangement of the Mechanical Components of the GuardedHot-Plate Apparatus Fig. 1 Illustration of Heat Flow in the Guarded-Hot-Plate Apparatus Fig.2 Example Report Form Fig. 3 Annexes Importance of Thickness A1.1 Measuring Thickness A1.2 Limitations Due to Apparatus A1.3 Limitations Due to Temperature A1.4 Limitations Due to Specimen A1.5 Random and Systematic Error Components A1.6 Error Components for Variables A1.7 Thermal Conductance or Thermal Resistance Error Analysis A1.8 Thermal Conductivity or Thermal Resistivity Error Analysis A1.9 Uncertainty Verification A1.10 1.15 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.16 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Note 22. 1.17 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 C177-19 Referenced Document

• 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 C1045 Standard Practice for Calculating Thermal Transmission Properties Under Steady-State Conditions
• ASTM C1058 Standard Practice for Selecting Temperatures for Evaluating and Reporting Thermal Properties of Thermal Insulation
• 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 C518 Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus
• ASTM C687 Standard Practice for Determination of Thermal Resistance of Loose-Fill Building Insulation
• ASTM E230 Standard Specification and Temperature-Electromotive Force (EMF) Tables for Standardized Thermocouples
• ASTM E691 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• ISO 8302 Thermal insulation; determination of steady-state thermal resistance and related properties; guarded hot plate apparatus

ASTM C177-19 history

• 2019 ASTM C177-19e1 Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus
• 2019 ASTM C177-19 Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus
• 2013 ASTM C177-13 Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus
• 2010 ASTM C177-10 Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus
• 2004 ASTM C177-04 Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus
• 1997 ASTM C177-97 Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus
• 1985 ASTM C177-85(1993)e1 Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus
• 0000 ASTM C177-85
• 1970 ASTM C177-76a