ASTM F2370-22

Standard Test Method for Measuring the Evaporative Resistance of Clothing Using a Sweating Manikin

SIGNIFICANCE AND USE
4.1 This test method can be used to quantify and compare the evaporative resistance provided by different clothing systems. The evaporative resistance values for ensembles measured under isothermal conditions can be used in models that predict the physiological responses of people in different environmental conditions. Garment evaporative resistance values can be compared as well (see Annex A1).  
4.2 The measurement of the evaporative resistance provided by clothing is complex and dependent upon the apparatus and techniques used. It is not practical in a test method of this scope to establish details sufficient to cover all contingencies. Departures from the instructions in this test method have the potential to lead to significantly different test results. Technical knowledge concerning the theory of heat transfer, moisture transfer, temperature, humidity, and air motion measurement, and testing practices is needed to evaluate which departures from the instructions given in this test method are significant. Standardization of the method reduces, but does not eliminate, the need for such technical knowledge. Report any departures with the results.
SCOPE
1.1 This test method covers the determination of the evaporative resistance of clothing ensembles. It describes the measurement of the resistance to evaporative heat transfer from a heated sweating thermal manikin to the testing environment. Information on measuring the local evaporative resistance values for individual garments and ensembles is provided in Annex A1.  
1.1.1 This is a static test that provides a baseline clothing measurement on a standing manikin.  
1.1.2 The effects of body position and movement are not addressed in this test method.  
1.2 The evaporative resistance values obtained apply only to the particular ensembles evaluated and for the specified environmental conditions of each test, particularly with respect to air movement and sweating simulations.  
1.3 Evaporative resistance values reported in SI units shall be 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: 30-Jun-2022
• ICS: 61.020 - Clothes
• Technical Committee: F23 - Personal Protective Clothing and Equipment
• Drafting Committee: F23.60 - Human Factors

Relations

• Refers: ASTM F1291-15 - Standard Test Method for Measuring the Thermal Insulation of Clothing Using a Heated Manikin
• Effective Date: 01-Nov-2015
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM E691-11 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2011
• Refers: ASTM F1291-10 - Standard Test Method for Measuring the Thermal Insulation of Clothing Using a Heated Manikin
• Effective Date: 01-Jan-2010
• Refers: ASTM E691-08 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Oct-2008
• Refers: ASTM E691-05 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2005
• Refers: ASTM F1291-05 - Standard Test Method for Measuring the Thermal Insulation of Clothing Using a Heated Manikin
• Effective Date: 15-Sep-2005
• Refers: ASTM F1291-04 - Standard Test Method for Measuring the Thermal Insulation of Clothing Using a Heated Manikin
• Effective Date: 01-Dec-2004
• Refers: ASTM F1291-99 - Standard Test Method for Measuring the Thermal Insulation of Clothing Using a Heated Manikin
• Effective Date: 10-Jun-1999
• Refers: ASTM E691-99 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 10-May-1999

Overview

ASTM F2370-22: Standard Test Method for Measuring the Evaporative Resistance of Clothing Using a Sweating Manikin provides a systematic approach to determining the evaporative resistance of clothing ensembles. Developed by ASTM International, this standard specifies how to measure the resistance to evaporative heat transfer from a heated, sweating manikin to the testing environment under controlled conditions.

Understanding the evaporative resistance of clothing is essential for evaluating how garments impact wearers’ comfort and physiological responses, especially in hot or humid conditions. This standardized method enables manufacturers, researchers, and safety professionals to compare different clothing systems and predict wearer comfort or stress in various environments.

Keywords: evaporative resistance, sweating manikin, protective clothing, thermal comfort, ASTM F2370-22

Key Topics

• Evaporative Resistance: Defined as the resistance to evaporative heat transfer from the body to the environment. Higher resistance implies less moisture vapor passes through clothing, impacting thermal comfort and heat stress.
• Sweating Manikin Use: The method employs a heated manikin capable of simulating human perspiration, ensuring accurate measurement of heat and moisture transfer.
• Isothermal vs. Non-Isothermal Testing: Isothermal tests maintain identical temperatures between the manikin and air, while non-isothermal tests simulate actual use environments.
• Test Conditions: Precise control of air temperature, humidity, and velocity within a test chamber is required for repeatable results.
• Sample Preparation: Garments are tested in their as-worn state or after prescribed cleaning to reflect intended use.
• Data Reporting: Results include average total evaporative resistance, intrinsic evaporative resistance of the clothing, testing conditions, and any deviations from the standard protocol.

Applications

• Personal Protective Equipment (PPE): Used to compare and improve the breathability of protective clothing, including firefighting gear, chemical suits, and medical ensembles.
• Research and Development: Supports product development by providing quantitative data on moisture management and thermal comfort of new garment designs or materials.
• Occupational Health and Safety: Assists in the selection or specification of workwear to reduce heat stress risks in hot and humid work environments.
• Performance Benchmarking: Enables comparison between different clothing systems or fabric technologies based on standardized evaporative resistance values.
• Thermal Comfort Modeling: Provides data for inclusion in models predicting human physiological responses, such as sweating rates, core temperature, and comfort in various environmental conditions.

Related Standards

• ASTM F1291 - Standard Test Method for Measuring the Thermal Insulation of Clothing Using a Heated Manikin. Used for determining the insulation value of clothing under similar conditions.
• ISO 9920:2007 - Ergonomics of the Thermal Environment-Estimation of Thermal Insulation and Evaporation Resistance of a Clothing Ensemble. International guideline referenced for clothing area factors and harmonized terms.
• ASTM E691 - Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method. Used for validating testing repeatability and reproducibility.

By using ASTM F2370-22, organizations can ensure comparability, reliability, and validity in the assessment of evaporative resistance in clothing, supporting informed decisions in clothing design, worker safety, and comfort optimization.

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: F2370 − 22
Standard Test Method for
Measuring the Evaporative Resistance of Clothing Using a
Sweating Manikin
This standard is issued under the fixed designation F2370; 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
Thetypeofclothingwornbypeopledirectlyaffectstheheatexchangebetweenthehumanbodyand
the environment. The heat transfer is both sensible (conduction, convection, and radiation) and latent
(evaporation). The evaporative resistance of a clothing ensemble is dependent upon the designs and
materials used in the component garments, the amount of body surface area covered by the clothing,
the distribution of the layers over the body, looseness or tightness of fit, and the increased surface area
forheatloss.Evaporativeresistancemeasurementsmadeonfabricsalonedonottakethesefactorsinto
account. Measurements of the resistance to evaporative heat loss provided by clothing can be used
with thermal resistance values (Test Method F1291) to determine the comfort or stress of people in
different environments.
1. Scope 1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This test method covers the determination of the evapo-
ization established in the Decision on Principles for the
rative resistance of clothing ensembles. It describes the mea-
Development of International Standards, Guides and Recom-
surement of the resistance to evaporative heat transfer from a
mendations issued by the World Trade Organization Technical
heated sweating thermal manikin to the testing environment.
Barriers to Trade (TBT) Committee.
Information on measuring the local evaporative resistance
values for individual garments and ensembles is provided in
2. Referenced Documents
Annex A1.
2.1 ASTM Standards:
1.1.1 This is a static test that provides a baseline clothing
E691 Practice for Conducting an Interlaboratory Study to
measurement on a standing manikin.
Determine the Precision of a Test Method
1.1.2 The effects of body position and movement are not
F1291 Test Method for Measuring the Thermal Insulation of
addressed in this test method.
Clothing Using a Heated Manikin
1.2 Theevaporativeresistancevaluesobtainedapplyonlyto
2.2 ISO Standards:
the particular ensembles evaluated and for the specified envi-
ISO 9920:2007 Ergonomics of the Thermal Environment—
ronmental conditions of each test, particularly with respect to
Estimation of the Thermal Insulation and Evaporation
air movement and sweating simulations.
Resistance of a Clothing Ensemble
1.3 Evaporative resistance values reported in SI units shall
3. Terminology
be regarded as standard.
1.4 This standard does not purport to address all of the 3.1 Definitions:
safety concerns, if any, associated with its use. It is the 3.1.1 clothing area factor (f ), n—the ratio of the surface
cl
responsibility of the user of this standard to establish appro- area of the clothed body to the surface area of the nude body.
priate safety, health, and environmental practices and deter-
3.1.2 clothing ensemble, n—a group of garments worn
mine the applicability of regulatory limitations prior to use.
together on the body at the same time.
1 2
This test method is under the jurisdiction ofASTM Committee F23 on Personal For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Protective Clothing and Equipment and is the direct responsibility of Subcommittee contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
F23.60 on Human Factors. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved July 1, 2022. Published August 2022. Originally the ASTM website.
approved in 2005. Last previous edition approved in 2016 as F2370 – 16. DOI: Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/F2370-22. 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
F2370 − 22
3.1.3 evaporative resistance, n—the resistance to evapora- 5. Apparatus
tive heat transfer from the body to the environment.
5.1 Manikin—A standing manikin shall be used that is
3.1.3.1 Discussion—The following evaporative resistance
formed in the shape and size of an adult male or female and
values can be determined in this test method when measured
heated to a constant average surface temperature.
under isothermal conditions:
5.1.1 Size and Shape—The manikin shall be constructed to
simulate the body of a human being; that is, it shall consist of
R = evaporativeresistanceoftheairlayeronthesurfaceof
ea
a head, chest/back, abdomen/buttocks, arms, hands (preferably
the sweating nude manikin.
with fingers extended to allow gloves to be worn), legs, and
R = totalevaporativeresistanceoftheclothingandsurface
et 2
feet. Total surface area shall be 1.8 6 0.3 m , and height shall
air layer around the manikin.
be170 610cm.Themanikin’sdimensionsshallcorrespondto
R = intrinsic evaporative resistance of the clothing. When
ecl
those required for standard sizes of garments because devia-
measurements are made under non-isothermal
tions in fit will affect the results.
conditions, the following apparent evaporative resis-
5.1.2 Sweat Generation—The manikin must have the ability
tance values can be determined.
to evaporate water from its entire surface.The sweating system
can be a water-fed capillary body suit worn over a thermal
3.1.3.2 Discussion—The following evaporative resistance
manikin. Sweating can also be simulated by supplying water to
values can be determined in this test method when measured
and maintaining it at the inner surface of a waterproof, but
under non-isothermal conditions. The term “apparent” is used
moisture-permeable fabric skin.
as a modifier for evaporative resistance to reflect the fact that
5.1.2.1 Sweating Surface Area—The entire surface of the
the properties of the specimen may be altered in the testing
manikin shall be heated and sweating.
condition and that condensation may occur within the clothing.
5.1.3 Surface Temperature—The manikin shall be con-
A
R = apparentevaporativeresistanceoftheairlayeronthe
structed so as to maintain a uniform temperature distribution
ea
surface of the sweating nude manikin.
overthenudebodysurface,withnolocalhotorcoldspots.The
A
R = apparent total evaporative resistance of the clothing
et mean surface (skin) temperature of the manikin shall be 35 °C.
and surface air layer around the manikin.
Local deviations from the mean surface temperature shall not
A
R = apparent intrinsic evaporative resistance of the
ecl
exceed 60.5 °C. Temperature uniformity of the nude manikin
clothing.
shall be evaluated at least once annually using an infrared
Total evaporative resistance values are measured directly thermal imaging system or equivalent method. This procedure
with a manikin. Intrinsic clothing evaporative resistance
shall also be repeated after repairs or alterations are completed
values are determined by subtracting the air layer resistance that could affect temperature uniformity, for example, replace-
around the clothed manikin from the total evaporative
ment of a heating element.
resistance value for the ensemble.
5.2 Power-Measuring Instruments—Power to the manikin
3.1.4 total thermal resistance (R)—the total thermal resis- shall be measured so as to give an average over the period of
t
a test. If time proportioning or phase proportioning is used for
tance (insulation) of the clothing and surface air layer around
power control, then devices that are capable of averaging over
the manikin.
the control cycle are required. Integrating devices (watt-hour
meters) are preferred over instantaneous devices (watt meters).
4. Significance and Use
Overall accuracy of the power monitoring equipment must be
4.1 This test method can be used to quantify and compare
within 62 % of the reading for the average power for the test
the evaporative resistance provided by different clothing sys-
period.Sincethereareavarietyofdevicesandtechniquesused
tems. The evaporative resistance values for ensembles mea-
for power measurement, no specified calibration procedures
sured under isothermal conditions can be used in models that
shall be given. However, an appropriate power calibration
predict the physiological responses of people in different
procedure is to be developed and documented.
environmental conditions. Garment evaporative resistance val-
5.3 Equipment for Measuring the Manikin’s Surface (Skin)
ues can be compared as well (see Annex A1).
Temperature—The mean surface temperature shall be mea-
4.2 Themeasurementoftheevaporativeresistanceprovided
sured with point sensors or distributed temperature sensors.
by clothing is complex and dependent upon the apparatus and
5.3.1 Point Sensors—Point sensors shall be thermocouples,
techniquesused.Itisnotpracticalinatestmethodofthisscope
resistance temperature devices (RTDs), thermistors, or equiva-
to establish details sufficient to cover all contingencies. Depar-
lent sensors. They shall be no more than 2 mm thick and shall
turesfromtheinstructionsinthistestmethodhavethepotential
be well bonded, both mechanically and thermally, to the
to lead to significantly different test results. Technical knowl-
manikin’s surface. Lead wires shall be bonded to the surface or
edge concerning the theory of heat transfer, moisture transfer,
pass through the interior of the manikin, or both. Each sensor
temperature, humidity, and air motion measurement, and test-
temperature shall be area-weighted when calculating the mean
ing practices is needed to evaluate which departures from the
instructions given in this test method are significant. Standard-
Information on laboratories with sweating manikins can be obtained from the
ization of the method reduces, but does not eliminate, the need
Textile Protection and Comfort Center, North Carolina State University, Raleigh,
for such technical knowledge. Report any departures with the
NC 27695 or from the Institute for Environmental Research, Kansas State
results. University, Manhattan, KS 66506.
F2370 − 22
surface temperature for the body. If point sensors are used, a be reported. If air velocity is monitored, then measurement
minimum of 17 point sensors are required.At least one sensor location requirements are the same as for temperature.
shall be placed on the head, chest, back, abdomen, buttocks,
and both the right and left upper arm, lower arm, hand, thigh, 6. Sampling and Test Specimens
calf, and foot. These sensors must be placed in the same
6.1 Sampling—It is desirable to test three identical en-
position for each test and the placement of the sensors shall be
sembles to reflect sample variability. However, if only one
given in the report.
ensemble is available (that is often the case with prototype
5.3.2 Distributed Sensors—If distributed sensors are used
garments), replicate measurements shall be made on one
(for example, resistance wire), then the sensors must be
ensemble.
distributed over the surface so that all areas are equally
6.1.1 If only one ensemble is available, the garments must
weighted. If several such sensors are used to measure the
be removed from the manikin after each test, dried, and
temperature of different parts of the body, then their respective
conditioned as specified in 6.4 before retesting.
temperaturesshallbearea-weightedwhencalculatingthemean
6.2 Specimen Size and Fit—Select the size of garments that
surface (skin) temperature. Distributed sensors shall be less
will fit the manikin appropriately (that is, the way the manu-
than 1 mm in diameter and firmly attached to the manikin
facturer designed them to be worn on the human body during
surface at all points.
their intended end use). For example, some knitted garments
5.4 Controlled Environmental Chamber—The manikin shall
are designed to fit the body relatively tightly. Others are
be placed in a chamber at least 1.5 by 1.5 by 2.5 m in
designed to fit loosely to accommodate a wider range of body
dimension that can provide uniform conditions, both spatially
dimensions or to allow other garments to be worn underneath.
and temporally.
In a stationary manikin test, large air layers in the clothing
5.4.1 Spatial Variations—Spatial variations shall not exceed
system will contribute to a higher evaporative resistance value
the following: air temperature 61 °C, relative humidity 65%,
than small air layers. Therefore, garments that do not have the
and air velocity 650 % of the mean value. In addition, the
appropriate fit on the manikin (that is, too tight or too loose)
mean radiant temperature shall not be more than 1.0 °C
will cause errors in measurement.
different from the mean air temperature.The spatial uniformity
6.2.1 When manikin measurements are used to compare
shall be verified at least annually or after any significant
materials used in certain garments, those garments must be
modificationsaremadetothechamber.Spatialuniformityshall
made from the same pattern so that design and fit variables are
be verified by recording values for the conditions stated above
held constant. In addition, they must be tested with the same
at heights of 0.1, 0.6, 1.1, 1.4, and 1.7 m above the floor at the
companion garments in the ensemble (for example, underwear,
location occupied by the manikin. Sensing devices specified
footwear, and so forth).
below shall be used when measuring the environmental con-
6.2.2 When manikin measurements are used to compare a
ditions.
variety of garments, the same size garments of a given type
5.4.2 Temporal Variations—Temporal variations shall not
shallbetestedasindicatedbythesizelabelinthegarments(for
exceed the following: air temperature 60.5 °C, mean radiant
example, large). However, if it is determined that the fit of a
temperature 60.5 °C, relative humidity 65 %, air velocity
garment is inappropriate, it is acceptable to use another size
620 % of the mean value for data averaged over 5 min (see
and state it in the report.
5.4.5).
6.3 Specimen Preparation—Garments shall be tested in the
5.4.3 Relative Humidity Measuring Equipment—Any hu-
as-received condition or after dry cleaning or laundering in
midity sensing device with an accuracy of 65 % relative
accordance with the manufacturer’s instructions. The cleaning
humidity and a repeatability of 63 % is acceptable (for
procedures and number of processings shall be stated in the
example, wet bulb/dry bulb, dew point hygrometer). Only one
report.
location needs to be monitored during a test to ensure that the
temporal uniformity requirements are met. 6.4 Conditioning—Allow the clothing components to come
to equilibrium with the atmosphere in the test chamber by
5.4.4 Air Temperature Sensors—Shielded air temperature
conditioning them in the chamber for at least 12 h.
sensors shall be used. Any sensor with an overall accuracy of
60.15 °C is acceptable (for example, RTD, thermocouple,
7. Calibration of Sweating Manikin
thermistor). The sensor shall have a time constant not exceed-
ing 1 min.The sensor(s) shall be 0.5 m in front of the manikin.
7.1 Calibration—Calibrate the sweating manikin using the
If a single sensor is used, it shall be 1.0 m above the floor. If
isothermal procedures in Section 8.
multiple sensors are used, they shall be spaced at equal height
7.1.1 The intrinsic clothing evaporative resistance of the
intervals and their readings averaged.
calibration ensemble (R ) is 0.016 (kPa·m /W), assuming the
ecl
5.4.5 Air Velocity Indicator—An omnidirectional anemom-
f value is 1.22.
cl
eter with 60.05 m/s accuracy shall be used. Measurements
7.2 Calibration Clothing Ensemble—The garments required
shall be averaged for at least 1 min at each location. If it is
for use in this calibration ensemble are:
demonstrated that velocity does not vary temporally by more
2 2
than 60.05 m/s, then it is not necessary to monitor air velocity 7.2.1 Protective Nomex III Shirt—203 g/m (6.0 oz/yd )
during a test. However, the value of the mean air velocity must plain weave Nomex IIIAbutton-up long-sleeve shirt (Bulwark
F2370 − 22
#SND6NV), with two chest pockets. The shirt tail shall hang 0.5 °C for all tests. The
...

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: F2370 − 16 F2370 − 22
Standard Test Method for
Measuring the Evaporative Resistance of Clothing Using a
Sweating Manikin
This standard is issued under the fixed designation F2370; 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
The type of clothing worn by people directly affects the heat exchange between the human body and
the environment. The heat transfer is both sensible (conduction, convection, and radiation) and latent
(evaporation). The evaporative resistance of a clothing ensemble is dependent upon the designs and
materials used in the component garments, the amount of body surface area covered by the clothing,
the distribution of the layers over the body, looseness or tightness of fit, and the increased surface area
for heat loss. Evaporative resistance measurements made on fabrics alone do not take these factors into
account. Measurements of the resistance to evaporative heat loss provided by clothing can be used
with thermal resistance values (Test Method F1291) to determine the comfort or stress of people in
different environments.
1. Scope
1.1 This test method covers the determination of the evaporative resistance of clothing ensembles. It describes the measurement
of the resistance to evaporative heat transfer from a heated sweating thermal manikin to a relatively calm the testing environment.
Information on measuring the local evaporative resistance values for individual garments and ensembles is provided in Annex A1.
1.1.1 This is a static test that provides a baseline clothing measurement on a standing manikin.
1.1.2 The effects of body position and movement are not addressed in this test method.
1.2 The evaporative resistance values obtained apply only to the particular ensembles evaluated and for the specified
environmental conditions of each test, particularly with respect to air movement and sweating simulations.
1.3 Evaporative resistance values reported in SI units shall be 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 safety, health, and healthenvironmental 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.
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 Oct. 1, 2016July 1, 2022. Published October 2016August 2022. Originally approved in 2005. Last previous edition approved in 20152016 as
F2370 - 15.F2370 – 16. DOI: 10.1520/F2370-16.10.1520/F2370-22.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2370 − 22
2. Referenced Documents
2.1 ASTM Standards:
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
2.2 ISO Standards:
ISO 9920:2007 Ergonomics of the Thermal Environment—Estimation of the Thermal Insulation and Evaporation Resistance of
a Clothing Ensemble
3. Terminology
3.1 Definitions:
3.1.1 clothing area factor (f ), n—the ratio of the surface area of the clothed body to the surface area of the nude body.
cl
3.1.2 clothing ensemble, n—a group of garments worn together on the body at the same time.
3.1.3 evaporative resistance, n—the resistance to evaporative heat transfer from the body to the environment.
3.1.3.1 Discussion—
The following evaporative resistance values can be determined in this test method when measured under isothermal
condititions:conditions:
R = evaporative resistance of the air layer on the surface of the sweating nude manikin.
ea
R = total evaporative resistance of the clothing and surface air layer around the manikin.
et
R = intrinsic evaporative resistance of the clothing. When measurements are made under non-isothermal conditions, the
ecl
following apparent evaporative resistance values can be determined.
AR = apparent evaporative resistance of the air layer on the surface of the sweating nude manikin.
ea
AR = apparent total evaporative resistance of the clothing and surface air layer around the manikin.
et
AR = apparent intrinsic evaporative resistance of the clothing.
ecl
Total evaporative resistance values are measured directly with a manikin. Intrinsic clothing evaporative resistance values are
determined by subtracting the air layer resistance around the clothed manikin from the total evaporative resistance value for the
ensemble.
3.1.3.2 Discussion—
The following evaporative resistance values can be determined in this test method when measured under non-isothermal
conditions. The term “apparent” is used as a modifier for evaporative resistance to reflect the fact that the properties of the
specimen may be altered in the testing condition and that condensation may occur within the clothing.
A
R = apparent evaporative resistance of the air layer on the surface of the sweating nude manikin.
ea
A
R = apparent total evaporative resistance of the clothing and surface air layer around the manikin.
et
A
R = apparent intrinsic evaporative resistance of the clothing.
ecl
Total evaporative resistance values are measured directly with a manikin. Intrinsic clothing evaporative resistance values are
determined by subtracting the air layer resistance around the clothed manikin from the total evaporative resistance value for the
ensemble.
3.1.4 total thermal resistance (R ) —)—the total thermal resistance (insulation) of the clothing and surface air layer around the
t
manikin.
4. Significance and Use
4.1 This test method can be used to quantify and compare the evaporative resistance provided by different clothing systems. The
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.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
F2370 − 22
evaporative resistance values for ensembles measured under isothermal conditions can be used in models that predict the
physiological responses of people in different environmental conditions. Garment evaporative resistance values can be compared
as well (see Annex A1).
4.2 The measurement of the evaporative resistance provided by clothing is complex and dependent upon the apparatus and
techniques used. It is not practical in a test method of this scope to establish details sufficient to cover all contingencies. Departures
from the instructions in this test method have the potential to lead to significantly different test results. Technical knowledge
concerning the theory of heat transfer, moisture transfer, temperature, humidity, and air motion measurement, and testing practices
is needed to evaluate which departures from the instructions given in this test method are significant. Standardization of the method
reduces, but does not eliminate, the need for such technical knowledge. Report any departures with the results.
5. Apparatus
5.1 Manikin—A standing manikin shall be used that is formed in the shape and size of an adult male or female and heated to a
constant average surface temperature.
5.1.1 Size and Shape—The manikin shall be constructed to simulate the body of a human being; that is, it shall consist of a head,
chest/back, abdomen/buttocks, arms, hands (preferably with fingers extended to allow gloves to be worn), legs, and feet. Total
surface area shall be 1.8 6 0.3 m , and height shall be 170 6 10 cm. The manikin’s dimensions shall correspond to those required
for standard sizes of garments because deviations in fit will affect the results.
5.1.2 Sweat Generation—The manikin must have the ability to evaporate water from its entire surface. The sweating system can
be a water-fed capillary body suit worn over a thermal manikin. Sweating can also be simulated by supplying water to and
maintaining it at the inner surface of a waterproof, but moisture-permeable fabric skin.
5.1.2.1 Sweating Surface Area—The entire surface of the manikin shall be heated and sweating including the head, chest, back,
abdomen, buttocks, arms, hands, legs, and feet.sweating.
5.1.3 Surface Temperature—The manikin shall be constructed so as to maintain a uniform temperature distribution over the nude
body surface, with no local hot or cold spots. The mean surface (skin) temperature of the manikin shall be 35°C.35 °C. Local
deviations from the mean surface temperature shall not exceed 60.5°C.60.5 °C. Temperature uniformity of the nude manikin shall
be evaluated at least once annually using an infrared thermal imaging system or equivalent method. This procedure shall also be
repeated after repairs or alterations are completed that could affect temperature uniformity, for example, replacement of a heating
element.
5.2 Power-Measuring Instruments—Power to the manikin shall be measured so as to give an average over the period of a test. If
time proportioning or phase proportioning is used for power control, then devices that are capable of averaging over the control
cycle are required. Integrating devices (watt-hour meters) are preferred over instantaneous devices (watt meters). Overall accuracy
of the power monitoring equipment must be within 62 % of the reading for the average power for the test period. Since there are
a variety of devices and techniques used for power measurement, no specified calibration procedures shall be given. However, an
appropriate power calibration procedure is to be developed and documented.
5.3 Equipment for Measuring the Manikin’s Surface (Skin) Temperature—The mean surface temperature shall be measured with
point sensors or distributed temperature sensors.
5.3.1 Point Sensors—Point sensors shall be thermocouples, resistance temperature devices (RTD’s),(RTDs), thermistors, or
equivalent sensors. They shall be no more than 2 mm thick and shall be well-bonded, well bonded, both mechanically and
thermally, to the manikin’s surface. Lead wires shall be bonded to the surface or pass through the interior of the manikin, or both.
Each sensor temperature shall be area-weighted when calculating the mean surface temperature for the body. If point sensors are
used, a minimum of 1517 point sensors are required. At least one sensor shall be placed on the head, chest, back, abdomen,
buttocks, and both the right and left upper arm, lower arm, hand, thigh, calf, and foot. These sensors must be placed in the same
position for each test and the placement of the sensors shall be given in the report.
5.3.2 Distributed Sensors—If distributed sensors are used (for example, resistance wire), then the sensors must be distributed over
Information on laboratories with sweating manikins can be obtained from the Textile Protection and Comfort Center, North Carolina State University, Raleigh, NC 27695
or from the Institute for Environmental Research, Kansas State University, Manhattan, KS 66506.
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the surface so that all areas are equally weighted. If several such sensors are used to measure the temperature of different parts
of the body, then their respective temperatures shall be area-weighted when calculating the mean surface (skin) temperature.
Distributed sensors shall be less than 1 mm in diameter and firmly attached to the manikin surface at all points.
5.4 Controlled Environmental Chamber—The manikin shall be placed in a chamber at least 1.5 by 1.5 by 2.5 m in dimension that
can provide uniform conditions, both spatially and temporally.
5.4.1 Spatial Variations—Spatial variations shall not exceed the following: air temperature 61°C,61 °C, relative humidity 65 %,
and air velocity 650 % of the mean value. In addition, the mean radiant temperature shall not be more than 1.0°C1.0 °C different
from the mean air temperature. The spatial uniformity shall be verified at least annually or after any significant modifications are
made to the chamber. Spatial uniformity shall be verified by recording values for the conditions stated above at heights of 0.1, 0.6,
1.1, 1.4, and 1.7 m above the floor at the location occupied by the manikin. Sensing devices specified below shall be used when
measuring the environmental conditions.
5.4.2 Temporal Variations—Temporal variations shall not exceed the following: air temperature 60.5°C,60.5 °C, mean radiant
temperature 60.5°C,60.5 °C, relative humidity 65 %, air velocity 620 % of the mean value for data averaged over 5 min.min
(see 5.4.5).
5.4.3 Relative Humidity Measuring Equipment—Any humidity sensing device with an accuracy of 65 % relative humidity and
a repeatability of 63 % is acceptable (for example, wet bulb/dry bulb, dew point hygrometer). Only one location needs to be
monitored during a test to ensure that the temporal uniformity requirements are met.
5.4.4 Air Temperature Sensors—Shielded air temperature sensors shall be used. Any sensor with an overall accuracy of
60.15°C60.15 °C is acceptable (for example, RTD, thermocouple, thermistor). The sensor shall have a time constant not
exceeding 1 min. The sensor(s) shall be 0.5 m in front of the manikin. If a single sensor is used, it shall be 1.0 m above the floor.
If multiple sensors are used, they shall be spaced at equal height intervals and their readings averaged.
5.4.5 Air Velocity Indicator—An omni-directionalomnidirectional anemometer with 60.05 m/s accuracy shall be used.
Measurements shall be averaged for at least 1 min at each location. If it is demonstrated that velocity does not vary temporally
by more than 60.05 m/s, then it is not necessary to monitor air velocity during a test. However, the value of the mean air velocity
must be reported. If air velocity is monitored, then measurement location requirements are the same as for temperature.
6. Sampling and Test Specimens
6.1 Sampling—It is desirable to test three identical ensembles to reflect sample variability. However, if only one ensemble is
available (that is often the case with prototype garments), replicate measurements shall be made on one ensemble.
6.1.1 If only one ensemble is available, the garments must be removed from the manikin after each test, dried, and conditioned
as specified in 6.4 before retesting.
6.2 Specimen Size and Fit—Select the size of garments that will fit the manikin appropriately (that is, the way the manufacturer
designed them to be worn on the human body during their intended end use). For example, some knitted garments are designed
to fit the body relatively tightly. Others are designed to fit loosely to accommodate a wider range of body dimensions or to allow
other garments to be worn underneath. In a stationary manikin test, large air layers in the clothing system will contribute to a higher
evaporative resistance value than small air layers. Therefore, garments that do not have the appropriate fit on the manikin (that is,
too tight or too loose),loose) will cause errors in measurement.
6.2.1 When manikin measurements are used to compare materials used in certain garments, those garments must be made from
the same pattern so that design and fit variables are held constant. In addition, they must be tested with the same companion
garments in the ensemble (for example, underwear, footwear, and so forth).
6.2.2 When manikin measurements are used to compare a variety of garments, the same size garments of a given type shall be
tested as indicated by the size label in the garments (for example, large). However, if it is determined that the fit of a garment is
inappropriate, it is acceptable to use another size and state it in the report.
6.3 Specimen Preparation—Garments shall be tested in the as-received condition or after dry cleaning or laundering in accordance
with the manufacturer’s instructions. The cleaning procedures and number of processings shall be stated in the report.
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6.4 Conditioning—Allow the clothing components to come to equilibrium with the atmosphere in the test chamber by conditioning
them in the chamber for at least 12 hours.h.
7. Calibration of Sweating Manikin
7.1 Calibration—Calibrate the sweating manikin using the isothermal procedures in Section 8.
7.1.1 The intrinsic clothing evaporative resistance of the calibration ensemble (R ) is 0.016 (kPa·m /W), assuming the f
eclecl clcl
value is 1.22.
7.2 Calibration Clothing Ensemble—The garments required for use in this calibration ensemble are:
2 2
7.2.1 Protective Nomex III Shirt—203 g/m (6.0 oz/yd ) plain weave Nomex IIIA button up long sleeve button-up long-sleeve shirt
(Bulwark #SND6NV), with two chest pockets. The shirttail shirt tail shall hang over the trousers, and the top button shall remain
unbuttoned.
2 2
7.2.2 Protective Nomex III Pants—203 g/m (6.0 oz/yd ) plain weave Nomex IIIA pants (Bulwark #PNW3NV), with two side
pockets and two back pockets.
2 2
7.2.3 Men’s Underwear Briefs—180 g/m (5.3 oz/yd ) 6 10 %, 100 % cotton jersey knit; jockey style that fits snugly at the waist
and legs.
2 2
7.2.4 Men’s T-Shirt—140 g/m (4.1 oz/yd ) 6 10 %, 100 % cotton jersey knit, short-sleeve, crew neck T-shirt.
7.2.5 Men’s Socks—Basic knit sock that covers foot and extends up the calf no more than 25.4 cm (10 in.) from the bottom of the
heel. Each individual sock must be composed of at least 75 % cotton and shall weigh 33 6 5 g.
7.2.6 Athletic Shoes—Fabric/soft leather and soft so
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