ASTM C202-19

Standard Test Method for Thermal Conductivity of Refractory Brick

SIGNIFICANCE AND USE
3.1 The thermal conductivity of refractory brick is a property required for selecting their thermal transmission characteristics. Users select refractory brick to provide specified conditions of heat loss and cold face temperature, without exceeding the temperature limitation of the brick. This test method establishes placement of thermocouples and positioning of test specimens in the calorimeter.  
3.2 This procedure must be used with Test Method C201 and requires a large thermal gradient and steady-state conditions. The results are based upon a mean temperature.  
3.3 The data from this test method are suitable for specification acceptance, estimating heat loss and surface temperature, and design of multi-layer refractory construction.  
3.4 The use of these data requires consideration of the actual application environment and conditions.
SCOPE
1.1 This test method supplements Test Method C201, and shall be used in conjunction with that test method to determine the thermal conductivity of refractory brick with the exception of insulating firebrick (use Test Method C182) and carbon refractories (use Test Method C767). This test method is designed for refractories having a conductivity factor of not more than 200 Btu·in./h·ft2·°F (28.8 W/m·K).  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 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.  
1.4 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.

General Information

• Status: Published
• Publication Date: 31-Mar-2019
• ICS: 81.080 - Refractories
• Technical Committee: C08 - Refractories
• Drafting Committee: C08.02 - Thermal Properties

Relations

• Replaces: ASTM C202-93(2013) - Standard Test Method for Thermal Conductivity of Refractory Brick
• Effective Date: 01-Apr-2019
• Refers: ASTM C767-20 - Standard Test Method for Thermal Conductivity of Carbon Refractories
• Effective Date: 01-Apr-2020
• Refers: ASTM C182-19 - Standard Test Method for Thermal Conductivity of Insulating Firebrick
• Effective Date: 01-Apr-2019
• Refers: ASTM E220-13 - Standard Test Method for Calibration of Thermocouples By Comparison Techniques
• Effective Date: 01-Nov-2013
• Refers: ASTM C182-88(2013) - Standard Test Method for Thermal Conductivity of Insulating Firebrick
• Effective Date: 01-Sep-2013
• Refers: ASTM C201-93(2013) - Standard Test Method for Thermal Conductivity of Refractories
• Effective Date: 01-Sep-2013
• Refers: ASTM C767-93(2013) - Standard Test Method for Thermal Conductivity of Carbon Refractories
• Effective Date: 01-Sep-2013
• Refers: ASTM C155-97(2013) - Standard Classification of Insulating Firebrick
• Effective Date: 01-Sep-2013
• Refers: ASTM C182-88(2009) - Standard Test Method for Thermal Conductivity of Insulating Firebrick
• Effective Date: 01-Mar-2009
• Refers: ASTM C201-93(2009) - Standard Test Method for Thermal Conductivity of Refractories
• Effective Date: 01-Mar-2009
• Refers: ASTM C767-93(2009) - Standard Test Method for Thermal Conductivity of Carbon Refractories
• Effective Date: 01-Mar-2009
• Refers: ASTM E220-07a - Standard Test Method for Calibration of Thermocouples By Comparison Techniques
• Effective Date: 01-Nov-2007
• Refers: ASTM E220-07e1 - Standard Test Method for Calibration of Thermocouples By Comparison Techniques
• Effective Date: 01-May-2007
• Refers: ASTM E220-07 - Standard Test Method for Calibration of Thermocouples By Comparison Techniques
• Effective Date: 01-May-2007
• Refers: ASTM C155-97(2007) - Standard Classification of Insulating Firebrick
• Effective Date: 01-Mar-2007

Overview

ASTM C202-19: Standard Test Method for Thermal Conductivity of Refractory Brick defines procedures for accurately determining the thermal conductivity of refractory brick materials, excluding insulating firebrick and carbon refractories. Knowing the thermal conductivity is essential for engineers, designers, and users in selecting refractory brick for applications requiring specified heat loss control and surface temperature containment. This method supplements ASTM C201 and is intended for use with bricks with a conductivity factor not exceeding 200 Btu·in./h·ft²·°F (28.8 W/m·K).

This ASTM standard ensures reliable measurement by specifying the placement of thermocouples, specimen preparation, and test setup in the calorimeter under steady-state conditions. The method’s results are crucial for heat transmission control and multi-layer refractory design in high-temperature industrial processes.

Key Topics

• Thermal Conductivity Measurement
  The standard outlines the laboratory procedure for embedding calibrated thermocouples within test specimens, ensuring accurate readings at two points in the refractory brick. The mean temperature is used as the basis for result calculations.

• Test Setup Requirements
  The procedure requires use of the calorimeter and guard assembly described in ASTM C201, enhanced with additional insulation and refractory fiber spacers. The setup creates a large, stable thermal gradient during testing.

• Specimen Preparation and Reheating
  Test specimens must be prepared precisely, with grooves for thermocouple wires and surfaces finished to tight tolerances. A high-temperature reheating cycle is necessary to stabilize material properties and ensure consistent thermal conductivity values.

• Data Collection and Reporting
  Multiple, timed measurements are taken at steady-state conditions. Results are averaged for reliability and must be reported in line with ASTM C201 guidelines.

• Safety and Compliance
  The standard emphasizes the responsibility of users to recognize and address safety, health, and environmental considerations in their laboratory and field settings.

Applications

• Industrial Furnace Lining
  Accurate thermal conductivity values are critical for designing furnace linings to meet specified heat loss and cold face temperature requirements.

• Specification Acceptance
  Test data produced using ASTM C202-19 enable manufacturers and buyers to verify that refractory bricks meet thermal performance specifications.

• Thermal Insulation Design
  Provides engineers with the necessary data to estimate heat loss, optimize refractory construction, and design multi-layer insulation systems in kilns, reactors, and other thermal processing equipment.

• Quality Assurance and Research
  Laboratory personnel use this method to ensure product quality and to support research into new refractory materials and construction solutions.

Related Standards

• ASTM C201 - Test Method for Thermal Conductivity of Refractories (primary reference for test apparatus and reporting)
• ASTM C182 - Test Method for Thermal Conductivity of Insulating Firebrick (for insulating firebrick only)
• ASTM C767 - Test Method for Thermal Conductivity of Carbon Refractories (for carbon-based materials)
• ASTM C155 - Classification of Insulating Firebrick (reference for backup insulation)
• ASTM E220 - Test Method for Calibration of Thermocouples by Comparison Techniques

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By following ASTM C202-19, organizations gain standardized, reliable data to inform the selection and application of refractory bricks, ensuring energy efficiency, safety, and compliance in high-temperature industrial operations. For the most accurate and up-to-date procedures, always consult the official ASTM publication.

Standards Content (Sample)

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.
Designation: C202 − 19
Standard Test Method for
Thermal Conductivity of Refractory Brick
This standard is issued under the fixed designation C202; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Comparison Techniques
1.1 This test method supplements Test Method C201, and
3. Significance and Use
shall be used in conjunction with that test method to determine
3.1 The thermal conductivity of refractory brick is a prop-
the thermal conductivity of refractory brick with the exception
erty required for selecting their thermal transmission charac-
of insulating firebrick (use Test Method C182) and carbon
teristics. Users select refractory brick to provide specified
refractories (use Test Method C767). This test method is
conditions of heat loss and cold face temperature, without
designed for refractories having a conductivity factor of not
exceeding the temperature limitation of the brick. This test
more than 200 Btu·in./h·ft ·°F (28.8 W/m·K).
method establishes placement of thermocouples and position-
1.2 The values stated in inch-pound units are to be regarded
ing of test specimens in the calorimeter.
as standard. The values given in parentheses are mathematical
3.2 This procedure must be used with Test Method C201
conversions to SI units that are provided for information only
and requires a large thermal gradient and steady-state condi-
and are not considered standard.
tions. The results are based upon a mean temperature.
1.3 This standard does not purport to address all of the
3.3 The data from this test method are suitable for specifi-
safety concerns, if any, associated with its use. It is the
cation acceptance, estimating heat loss and surface
responsibility of the user of this standard to establish appro-
temperature, and design of multi-layer refractory construction.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
3.4 Theuseofthesedatarequiresconsiderationoftheactual
1.4 This international standard was developed in accor-
application environment and conditions.
dance with internationally recognized principles on standard-
4. Apparatus
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
4.1 The apparatus shall consist of that described in Test
mendations issued by the World Trade Organization Technical
Method C201 with the addition of thermocouples, back-up
Barriers to Trade (TBT) Committee.
insulation, and refractory fiber paper as described in Sections 6
and 7 of this test method.
2. Referenced Documents
5. Test Specimens
2.1 ASTM Standards:
C155 Classification of Insulating Firebrick
5.1 The test specimens shall be selected and prepared in
C182 Test Method for Thermal Conductivity of Insulating
accordance with Test Method C201.
Firebrick
6. Installation of Thermocouples in Test Specimen
C201 Test Method for Thermal Conductivity of Refractories
C767 Test Method for Thermal Conductivity of Carbon
6.1 Thermocouples—Calibrated thermocouples shall be
Refractories
embedded in the test specimen at two points for measuring
E220 Test Method for Calibration of Thermocouples By
temperature. Platinum-10 % rhodium⁄platinum thermocouples
shall be used.Wire ofAWG Gage 28 (0.320 mm) shall be used
in making the thermocouples.
This test method is under the jurisdiction of ASTM Committee C08 on
6.2 Installation of Thermocouples—The hot junction of the
Refractories and is the direct responsibility of Subcommittee C08.02 on Thermal
Properties. thermocouplesshallbeplacedinthecenterofeach9by4 ⁄2-in.
Current edition approved April 1, 2019. Published May 2019. Originally
(228 by 114-mm) face and just below the surface of the test
approved in 1945. Last previous edition approved in 2013 as C202 – 93 (2013).
specimen. Grooves to receive the wire shall be cut in each 9 by
DOI: 10.1520/C0202-19.
1 1
2 4 ⁄2-in. (228 by 114-mm) face of the brick to a depth of ⁄32 in.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. Test Method E220 specifies calibration procedures for thermocouples.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C202 − 19
(0.8 mm) by means of an abrasive wheel 0.02 in. (0.5 mm) in parallel by more than 60.01 in (0.3 mm). The sides of the
thickness. The layout for the grooves allows all of the cold piecesthataretobeplacedincontactshallbegroundplaneand
junction ends of the wires to extend from one end of the brick. at right angles to the horizontal faces. The joints between the
Agroove shall be cut in the center of each 9 by 4 ⁄2-in. (228 by pieces shall be tight without the use of any mortar.
114-mm) face along the 4 ⁄2-in. (114-mm) dimension and
1 1
7.2 Two strips of refractory fiber paper 13 ⁄2 by ⁄2 by
ending 1 in. (25.4 mm) from each edge. The path of each
0.02 in. (343 by 13 by 0.5 mm) shall be placed along the
groove is extended at an angle of 90° to one end of the brick
13 ⁄2-in. (343-mm) dimension of the inner guard at the outside
by cutting grooves parallel to and 1.0 in. (25.4 mm) from the
edges. Twelve strips of refractory fiber paper 2 by ⁄2 by
edge of the specimen. Before cementing the thermocouple
0.02 in. (51 by 13 by 0.5 mm) shall be placed on the outer
wires in place, measurements shall be taken to obtain, within
guard at intervals in the pattern shown in Fig. 1. These strips
60.01 in. (0.3 mm), the eventual distance between the center
serve as spacers to prevent contact between the test material
lines of the thermocouple junctions. This shall be done by
andthecalorimeterassembly.Theback-upinsulationshallthen
measuring the 2 ⁄2-in. (64-mm) dimension of the brick at the
be placed on the calorimeter assembly so as to provide a level
location for the hot junctions and deducting the distance
and plane surface.Additional strips of refractory fiber paper of
between the center line of each junction in its embedded
the same dimensions shall be placed in the same pattern upon
position and the surface of the brick.
the back-up insulation. These strips serve as spacers to prevent
contact between the fireclay brick and the back-up insulation.
7. Set-Up of Back-Up Insulation, Specimen, and Silicon
Carbide Slab The test specimen shall be placed centrally over the center of
the calorimeter section on its 9 by 4 ⁄2-in. (228 by 114-mm)
7.1 The calorimeter and inner and outer guards shall be
face, the guard brick placed at the sides of the test specimen so
covered with a 0.50-in. (12.7-mm) thick layer of Group 20
as to completely cover the calorimeter and inner guard area,
insulating firebrick (see Classification C155)
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C202 − 93 (Reapproved 2013) C202 − 19
Standard Test Method for
Thermal Conductivity of Refractory Brick
This standard is issued under the fixed designation C202; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method supplements Test Method C201, and shall be used in conjunction with that test method to determine the
thermal conductivity of refractory brick with the exception of insulating firebrick (use Test Method C182),) and carbon refractories.
refractories (use Test Method C767). This test method is designed for refractories having a conductivity factor of not more than
200 Btu·in./h·ft ·°F (28.8 W/m·K).
1.2 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are
mathematical conversions to SI units that are provided for information only and are not considered standard.
1.2.1 Exception—Certain flow and weight measurements are expressed in SI units only.
1.3 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
C155 Classification of Insulating Firebrick
C182 Test Method for Thermal Conductivity of Insulating Firebrick
C201 Test Method for Thermal Conductivity of Refractories
C767 Test Method for Thermal Conductivity of Carbon Refractories
E220 Test Method for Calibration of Thermocouples By Comparison Techniques
3. Significance and Use
3.1 The thermal conductivity of refractory brick is a property required for selecting their thermal transmission characteristics.
Users select refractory brick to provide specified conditions of heat loss and cold face temperature, without exceeding the
temperature limitation of the brick. This test method establishes placement of thermocouples and positioning of test specimens in
the calorimeter.
3.2 This procedure must be used with Test Method C201 and requires a large thermal gradient and steady state steady-state
conditions. The results are based upon a mean temperature.
3.3 The data from this test method are suitable for specification acceptance, estimating heat loss and surface temperature, and
design of multi-layer refractory construction.
3.4 The use of these data requires consideration of the actual application environment and conditions.
4. Apparatus
4.1 The apparatus shall consist of that described in Test Method C201 with the addition of thermocouples, back-up insulation,
and refractory fiber paper as described in Sections 6 and 7 of this test method.
This test method is under the jurisdiction of ASTM Committee C08 on Refractories and is the direct responsibility of Subcommittee C08.02 on Thermal Properties.
Current edition approved Sept. 1, 2013April 1, 2019. Published September 2013May 2019. Originally approved in 1945. Last previous edition approved in 20092013 as
ε1
C202 – 93 (2009)(2013). . DOI: 10.1520/C0202-93R13.10.1520/C0202-19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C202 − 19
5. Test Specimens
5.1 The test specimens shall be selected and prepared in accordance with Test Method C201.
6. Installation of Thermocouples in Test Specimen
6.1 Thermocouples—Calibrated thermocouples shall be embedded in the test specimen at two points for measuring
temperature. Platinum-10 % rhodium ⁄platinum thermocouples shall be used. Wire of AWG Gage 28 (0.320 mm) shall be used in
making the thermocouples.
6.2 Installation of Thermocouples—The hot junction of the thermocouples shall be placed in the center of each 9-9 by 4 ⁄2-in.
(228-(228 by 114-mm) face and just below the surface of the test specimen. Grooves to receive the wire shall be cut in each 9-9
1 1
by 4 ⁄2-in. (228-(228 by 114-mm) face of the brick to a depth of ⁄32 in. (0.8 mm) by means of an abrasive wheel 0.02 in. (0.5 mm)
(0.5 mm) in thickness. The layout for the grooves allows all of the cold junction ends of the wires to extend from one end of the
1 1
brick. A groove shall be cut in the center of each 9 by 4 ⁄2-in. (228-(228 by 114-mm) face along the 4 ⁄2-in. (114-mm) dimension
and ending 1 in. (25.4 mm) from each edge. The path of each groove is extended at an angle of 90° to one end of the brick by
cutting grooves parallel to and 1.0 in. (25.4 mm) from the edge of the specimen. Before cementing the thermocouple wires in
place, measurements shall be taken to obtain, within 60.01 in. (0.3 mm), the eventual distance between the center lines of the
thermocouple junctions. This shall be done by measuring the 2 ⁄2-in. (64-mm) dimension of the brick at the location for the hot
junctions and deducting the distance between the center line of each junction in its embedded position and the surface of the brick.
7. Set-Up of Back-Up Insulation, Specimen, and Silicon Carbide Slab
7.1 The calorimeter and inner and outer guards shall be covered with a 0.50-in. (12.7-mm) thick layer of Group 20 insulating
firebrick (see Classification C155) for the purpose of obtaining a higher mean temperature in the test specimen than would result
by placing the specimen directly over the calorimeter area. The back-up insulation shall be cut and ground so as to provide surfaces
that are plane and do not vary from parallel by more than 60.01 in (0.3 mm). The sides of the pieces that are to be placed in contact
shall be ground plane and at right angles to the horizontal faces. The joints between the pieces shall be tight without the use of
any mortar.
FIG. 1 Arrangement of Refractory Fiber Paper Strips in Calorimeter Assemblage
Test Method E220 specifies calibration procedures for thermocouples.
Alundum Cement RA 562 supplied by the Norton Co., One New Bond St., Worcester, MA 01606, is satisfactory for this purpose.
C202 − 19
1 1 1
7.2 Two strips of refractory fiber paper 13 ⁄2 by ⁄2 by 0.02 in. 0.02 in. (343 by 13 by 0.5 mm) shall be placed along the 13 ⁄2-in.
(343 mm) (343-mm) dimension of the inner guard at the outside edges. Twelve strips of refractory fiber paper 2 by ⁄2 by 0.02 in.
0.02 in. (51 by 13 by 0.5 mm) shall be placed on the outer guard at intervals in the pattern shown in Fig. 1. These strips serve as
spacers to prevent contact between the test material and the cal
...