ASTM F1868-23

Standard Test Method for Thermal Resistance, Evaporative Resistance, and Total Heat Loss Measurements of Clothing Materials Using a Sweating Hot Plate

SIGNIFICANCE AND USE
4.1 The thermal resistance, evaporative resistance, and total heat loss provided by fabrics, films, coatings, foams, and leathers, including multi-layer assemblies, is of considerable importance in determining their suitability for use in fabricating protective clothing systems.  
4.1.1 The thermal resistance, evaporative resistance, and total heat loss can be significantly affected by environmental conditions. Extreme care must be taken when using results measured under standard testing conditions to determine a material’s suitability for use in conditions outside the testing conditions.  
4.2 The thermal interchange between people and their environment is an extremely complicated subject that involves many factors in addition to the steady-state resistance values of fabrics, films, coatings, foams, and leathers, including multi-layer assemblies. Therefore, thermal resistance values, evaporative resistance values, and total heat loss measured on a hot plate may or may not indicate relative merit of a particular material or system for a given clothing application. While a possible indicator of clothing performance, measurements produced by the testing of fabrics have no proven correlation to the performance of clothing systems worn by people. Clothing weight, drape, tightness of fit, and so forth, can minimize or even neutralize the apparent differences between fabrics or fabric assemblies measured by this test method.  
4.3 The thermal resistance and evaporative resistance of clothing systems and items can be measured with a heated sweating manikin in an environmental chamber in accordance with Test Methods F1291, F2370, and F3426.
SCOPE
1.1 This test method covers the measurement of the thermal resistance, evaporative resistance, and total heat loss under steady-state conditions of fabrics, films, coatings, foams, and leathers, including multi-layer assemblies, for use in clothing systems.  
1.2 The range of this measurement technique for intrinsic thermal resistance is from 0.002 to 0.5 K·m2/W and for intrinsic evaporative resistance is from 0.0 to 1.0 kPa·m 2/W. The total heat loss range is from 0.0 to 1300 W/m2.  
1.3 The values in SI units shall be regarded as standard. Other units of measurement are provided in this standard but are not regarded as standard.  
1.4 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.  
1.5 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-May-2023
• ICS: 13.340.10 - Protective clothing
• Technical Committee: F23 - Personal Protective Clothing and Equipment
• Drafting Committee: F23.60 - Human Factors

Relations

• Refers: ASTM F3426-20 - Standard Test Method for Measuring the Thermal Insulation of Clothing Items Using Heated Manikin Body Forms
• Effective Date: 15-Jul-2020

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: F1868 − 23
Standard Test Method for
Thermal Resistance, Evaporative Resistance, and Total Heat
Loss Measurements of Clothing Materials Using a Sweating
1
Hot Plate
This standard is issued under the fixed designation F1868; 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.
INTRODUCTION
Clothing is often made of materials that impede the flow of heat and moisture from the skin to the
environment. Consequently, people may suffer from heat stress or cold stress when wearing clothing
in different environmental conditions. Therefore, it is important to quantify the thermal resistance,
evaporative resistance, and total heat loss of clothing materials and to consider these properties when
selecting materials for different clothing applications.
1. Scope 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This test method covers the measurement of the thermal
C177 Test Method for Steady-State Heat Flux Measure-
resistance, evaporative resistance, and total heat loss under
ments and Thermal Transmission Properties by Means of
steady-state conditions of fabrics, films, coatings, foams, and
the Guarded-Hot-Plate Apparatus
leathers, including multi-layer assemblies, for use in clothing
D1518 Test Method for Thermal Resistance of Batting
systems.
3
Systems Using a Hot Plate (Withdrawn 2023)
1.2 The range of this measurement technique for intrinsic
E177 Practice for Use of the Terms Precision and Bias in
2
thermal resistance is from 0.002 to 0.5 K·m /W and for
ASTM Test Methods
2
intrinsic evaporative resistance is from 0.0 to 1.0 kPa·m /W.
E691 Practice for Conducting an Interlaboratory Study to
2
The total heat loss range is from 0.0 to 1300 W/m .
Determine the Precision of a Test Method
F1291 Test Method for Measuring the Thermal Insulation of
1.3 The values in SI units shall be regarded as standard.
Clothing Using a Heated Manikin
Other units of measurement are provided in this standard but
F1494 Terminology Relating to Protective Clothing
are not regarded as standard.
F2370 Test Method for Measuring the Evaporative Resis-
1.4 This standard does not purport to address all of the
tance of Clothing Using a Sweating Manikin
safety concerns, if any, associated with its use. It is the
F3426 Test Method for Measuring the Thermal Insulation of
responsibility of the user of this standard to establish appro-
Clothing Items Using Heated Manikin Body Forms
priate safety, health, and environmental practices and deter-
2.2 Other Standards:
mine the applicability of regulatory limitations prior to use.
ISO 11092 Textiles – Physiological Effects – Measurement
1.5 This international standard was developed in accor-
of Thermal and Water-Vapour Resistance Under Steady-
4
dance with internationally recognized principles on standard-
State Conditions (Sweating Guarded-Hotplate Test)
ization established in the Decision on Principles for the
3. Terminology
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
3.1 Definitions:
Barriers to Trade (TBT) Committee.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
1
This test method is under the jurisdiction of ASTM Committee F23 on Personal Standards volume information, refer to the standard’s Document Summary page on
Protective Clothing and Equipment and is the direct responsibility of Subcommittee the ASTM website.
3
F23.60 on Human Factors. The last approved version of this historical standard is referenced on
Current edition approved June 1, 2023. Published June 2023. Originally www.astm.org.
4
approved in 1998. Last previous edition approved in 2017 as F1868 – 17. DOI: Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/F1868-23. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
F1868 − 23
3.1.1 clo, n—a unit of thermal resistance (insulation) equal plate without a fabric test specimen (that is, bare plate). This
2
to 0.155 K·m /W. property reflects the instrument constant and is used to stan-
3.1.1.1 Discussion—The value of the clo was selected as dardize the plate, and in conjunction with R , is used in the
ct
roughly the insulation value of typical in
...

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: F1868 − 17 F1868 − 23
Standard Test Method for
Thermal and Evaporative Resistance Resistance,
Evaporative Resistance, and Total Heat Loss Measurements
1
of Clothing Materials Using a Sweating Hot Plate
This standard is issued under the fixed designation F1868; 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.
INTRODUCTION
Clothing is often made of materials that impede the flow of heat and moisture from the skin to the
environment. Consequently, people may suffer from heat stress or cold stress when wearing clothing
in different environmental conditions. Therefore, it is important to quantify the thermal resistance and
evaporative resistance resistance, evaporative resistance, and total heat loss of clothing materials and
to consider these properties when selecting materials for different clothing applications.
1. Scope
1.1 This test method covers the measurement of the thermal resistance and the evaporative resistance, under steady-state
conditions,resistance, evaporative resistance, and total heat loss under steady-state conditions of fabrics, films, coatings, foams, and
leathers, including multi-layer assemblies, for use in clothing systems.
2
1.2 The range of this measurement technique for intrinsic thermal resistance is from 0.002 to 0.5 K·m /W and for intrinsic
2 2
evaporative resistance is from 0.0 to 1.0 kPa·m /W. The total heat loss range is from 0.0 to 1300 W/m .
1.3 The values in SI units shall be regarded as standard. No other Other units of measurement are included in this provided in this
standard but are not regarded as standard.
1.4 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 consult and establish appropriate safety and healthsafety, health, and environmental practices and
determine the applicability of regulatory limitations prior to use.
1.5 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
2.1 ASTM Standards:
1
This test method is under the jurisdiction of ASTM Committee F23 on Personal Protective Clothing and Equipment and is the direct responsibility of Subcommittee
F23.60 on Human Factors.
Current edition approved June 1, 2017June 1, 2023. Published June 2017June 2023. Originally approved in 1998. Last previous edition approved in 20142017 as
F1868 – 14.F1868 – 17. DOI: 10.1520/F1868-17.10.1520/F1868-23.
2
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
1

---------------------- Page: 1 ----------------------
F1868 − 23
C177 Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the
Guarded-Hot-Plate Apparatus
3
D1518 Test Method for Thermal Resistance of Batting Systems Using a Hot Plate (Withdrawn 2023)
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
F1291 Test Method for Measuring the Thermal Insulation of Clothing Using a Heated Manikin
F1494 Terminology Relating to Protective Clothing
F2370 Test Method for Measuring the Evaporative Resistance of Clothing Using a Sweating Manikin
F3426 Test Method for Measuring the Thermal Insulation of Clothing Items Using Heated Manikin Body Forms
2.2 Other Standards:
ISO 11092 Textiles – Physiological Effects – Measurement of Thermal and Water-Vapour Resistance Under Steady-State
4
Conditions (Sweating Guarded-Hotplate Test)
3. Terminology
3.1 Definitions:
2
3.1.1 clo, n—a unit of thermal resistance (insulation) equal to 0.155 K·m /W.
3.1.1.1 Discussion—
The value of the clo was selected as roughly the insulation value of typical indoor clothing, which should keep a resting ma
...