ASTM F1720-17(2023)

Standard Test Method for Measuring Thermal Insulation of Sleeping Bags Using a Heated Manikin

SIGNIFICANCE AND USE
5.1 This test method can be used to quantify and compare the insulation provided by sleeping bags or sleeping bag systems. It can be used for material and design evaluations.  
5.2 The measurement of the insulation provided by clothing (see Test Method F1291, ISO 15831) and sleeping bags (ISO 23537) is complex and dependent on the apparatus and techniques used. It is not practical in a test method of this scope to establish details sufficient to cover all contingencies. It is feasible that departures from the instructions in this test method will lead to significantly different test results. Technical knowledge concerning the theory of heat transfer, temperature 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. Any departures need to be reported with the results.
SCOPE
1.1 This test method covers determination of the insulation value of a sleeping bag or sleeping bag system. It measures the resistance to dry heat transfer from a constant skin temperature manikin to a relatively cold environment. This is a static test that generates reproducible results, but the manikin cannot simulate real life sleeping conditions relating to some human and environmental factors, examples of which are listed in the introduction.  
1.2 The insulation values obtained apply only to the sleeping bag or sleeping bag system, as tested, and for the specified thermal and environmental conditions of each test, particularly with respect to air movement past the manikin.  
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-Oct-2023
• ICS: 17.200.10 - Heat. Calorimetry
• ICS: 59.080.99 - Other products of the textile industry
• Technical Committee: F08 - Sports Equipment, Playing Surfaces, and Facilities
• Drafting Committee: F08.22 - Camping Softgoods

Relations

• Replaces: ASTM F1720-17 - Standard Test Method for Measuring Thermal Insulation of Sleeping Bags Using a Heated Manikin
• Effective Date: 01-Nov-2023

Overview

ASTM F1720-17(2023): Standard Test Method for Measuring Thermal Insulation of Sleeping Bags Using a Heated Manikin provides a standardized approach for determining and comparing the thermal insulation of sleeping bags and sleeping bag systems. Developed by ASTM International, this method uses a heated manikin to measure the resistance to dry heat transfer, offering precision and repeatability in assessing how well sleeping bags protect users from cold environments. This standard is essential for manufacturers, designers, and quality control personnel in the outdoor and camping equipment industry, enabling reliable comparisons and performance validations under controlled conditions.

Key Topics

• Thermal Insulation Measurement: The standard defines procedures for quantifying insulation in "clo" units-the same units used for clothing insulation-by simulating human heat loss.
• Test Environment Standardization: Details environmental chamber requirements such as consistent air temperature, humidity, and air flow to ensure reproducible and comparable results.
• Heated Manikin Setup: Specifies the configuration and calibration of life-size, human-shaped heated manikins to represent typical adult sleeping postures and maintain controlled temperature throughout the test.
• Test Procedures: Outlines options for evaluating standalone sleeping bags or complete systems (with auxiliary products like pads or liners), emphasizing the importance of following strict protocols to reduce measurement variability.
• Safety and Reporting: The standard emphasizes operator safety, accuracy, and transparency, requiring clear disclosure of any deviations from the prescribed methodology.

Applications

ASTM F1720-17(2023) finds broad application in the design, testing, and quality assurance of sleeping bags for various environments:

• Product Development: Provides comparative data for selecting materials and optimizing sleeping bag construction to achieve target insulation performance.
• Certification & Compliance: Serves as a basis for third-party testing, product labeling, and compliance with procurement standards, especially for military and outdoor recreational markets.
• Consumer Guidance: Insulation values measured using this standard contribute to reliable temperature ratings, helping consumers choose appropriate gear for different climates and conditions.
• Quality Assurance: Manufacturers and testing laboratories use this method for batch testing, ensuring product consistency and meeting quality specifications.
• Research & Benchmarking: The method supports academic and industry research into new insulating materials, combinations, and sleeping systems for enhanced comfort and safety in cold environments.

Related Standards

ASTM F1720 is part of an international network of standards addressing thermal insulation measurements for sleeping products and clothing:

• ASTM F1291: Test Method for Measuring the Thermal Insulation of Clothing Using a Heated Manikin
• ISO 15831: Measurement of Thermal Insulation by Means of a Thermal Manikin
• ISO 23537-1: Requirements for Sleeping Bags – Part 1: Thermal and Dimensional Requirements

These related standards help harmonize global approaches to thermal testing, enabling consistent evaluations across different products and regulatory contexts.

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Keywords: ASTM F1720, heated manikin, sleeping bag insulation, thermal resistance, clo units, camping gear standards, sleeping bag system testing, outdoor equipment quality, ISO sleeping bag standards, thermal testing.

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: F1720 − 17 (Reapproved 2023) An American National Standard
Standard Test Method for
Measuring Thermal Insulation of Sleeping Bags Using a
Heated Manikin
This standard is issued under the fixed designation F1720; 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
Sleeping bags are used by people in outdoor environments to insulate them from the cold (that is,
reduce their body heat loss to the environment). Sleeping bags often are used with ground pads and
clothing inside tents that provide additional protection from the environment. The amount of
insulation needed in a sleeping bag depends upon the air temperature and a number of other
environmental factors (for example, wind speed, radiant temperature, moisture in the air), human
factors (for example, a person’s metabolic heat production that is affected by gender, age, fitness level,
body type, size, position, and movement), and physical factors (for example, amount of body coverage
and the quality of the insulating materials). The insulation value, expressed in clo units, can be used
to characterize sleeping bags and sleeping bag systems. Insulation values for sleeping bag systems can
be used in body heat loss models to predict the temperature ratings for comfort.
1. Scope mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This test method covers determination of the insulation
value of a sleeping bag or sleeping bag system. It measures the
2. Referenced Documents
resistance to dry heat transfer from a constant skin temperature
2.1 ASTM Standards:
manikin to a relatively cold environment. This is a static test
F1291 Test Method for Measuring the Thermal Insulation of
that generates reproducible results, but the manikin cannot
Clothing Using a Heated Manikin
simulate real life sleeping conditions relating to some human
2.2 ISO Standards:
and environmental factors, examples of which are listed in the
ISO 15831 2004 Clothing—Physiological Effects—
introduction.
Measurement of Thermal Insulation by Means of a Ther-
1.2 The insulation values obtained apply only to the sleep-
mal Manikin
ing bag or sleeping bag system, as tested, and for the specified
ISO 23537-1 2016 Requirements for Sleeping Bags – Part 1:
thermal and environmental conditions of each test, particularly
Thermal and Dimensional Requirements
with respect to air movement past the manikin.
1.3 This standard does not purport to address all of the 3. Terminology
safety concerns, if any, associated with its use. It is the
3.1 Definitions:
responsibility of the user of this standard to establish appro-
3.1.1 auxiliary products, n—items used with a sleeping bag
priate safety, health, and environmental practices and deter-
to create a sleeping bag system such as clothing, camp pillow,
mine the applicability of regulatory limitations prior to use.
ground pad, and bivy sack.
1.4 This international standard was developed in accor-
3.1.2 clo, n—unit of thermal resistance (insulation) equal to
dance with internationally recognized principles on standard-
0.155°C·m /W.
ization established in the Decision on Principles for the
3.1.2.1 Discussion—The value of 1 clo was selected as
Development of International Standards, Guides and Recom-
roughly the insulation value of a heavy men’s business suit,
1 2
This test method is under the jurisdiction of ASTM Committee F08 on Sports For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Equipment, Playing Surfaces, and Facilities and is the direct responsibility of contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Subcommittee F08.22 on Camping Softgoods. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Nov. 1, 2023. Published December 2023. Originally the ASTM website.
approved in 1996. Last previous edition approved in 2017 as F1720 – 17. DOI: Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/F1720-17R23. 4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1720 − 17 (2023)
which should keep a resting man (producing heat at the rate of 6. Apparatus
58 W/m ) comfortable in an environment at 21 °C, air move- 4
6.1 Manikin —Use a supine manikin that is formed in the
ment 0.1 m/s.
shape and size of an adult male or female and is capable of
being heated to a constant, average surface temperature.
3.1.3 dry heat loss, n—heat transferred from the body
6.1.1 Size and Shape—Construct the manikin to simulate
surface to a cooler environment by means of conduction,
the body of a human being, that is, with a head, chest/back,
convection, and radiation.
abdomen/buttocks, arms, hands, legs, and feet. Total surface
2 2
3.1.4 manikin, n—a life-size model of the human body with
area shall be 1.8 m 6 0.3 m , and height shall be 170 cm 6
a surface temperature similar to that of a human being.
10 cm. Any departures from this description need to be
reported.
3.1.5 sleeping bag, n—a structure made of down, synthetic
6.1.2 Surface Temperature—Construct the manikin so as to
fiberfill, shell fabrics, or other materials, or a combination
maintain a constant temperature distribution over the entire
thereof, that is designed for people to use for thermal protec-
nude body surface with no local hot or cold spots. Ensure that
tion when sleeping (for example, outdoors, tent, cabin).
the mean skin temperature of the manikin is either 34 °C or
3.1.6 sleeping bag system, n—sleeping bag used with aux-
35 °C. Do not allow local deviations from the mean skin
iliary products such as clothing, ground pad, and bivy sack.
temperature to exceed 60.3 °C. Evaluate temperature unifor-
mity of the nude manikin at least once annually using an
3.1.7 thermal insulation, n—resistance to dry heat transfer
infrared thermal imaging system, a surface (contact) tempera-
by way of conduction, convection, and radiation.
ture probe, or equivalent method. This procedure also needs to
3.1.8 total insulation (I ), n—the resistance to dry heat loss
T be repeated after repairs or alterations are completed that could
from the manikin that includes the resistance provided by the
affect temperature uniformity, for example, replacing a heating
sleeping bag, auxiliary products (if used) and the surface air
element.
layer around the manikin.
6.2 Power-Measuring Instruments—Measure the power to
3.1.8.1 Discussion—Total insulation values (I ) are mea-
T
the manikin so as to give an accurate average over the period
sured directly with a manikin. They can be used to compare
of a test. If time proportioning or phase proportioning is used
different sleeping bags, as long as each test is conducted using
for power control, then devices that are capable of averaging
the same experimental procedures and test conditions.
over the control cycle are required. Integrating devices (watt-
hour meters) are preferred over instantaneous devices (watt
4. Summary of Test Method
meters). Overall accuracy of the power monitoring equipment
must be within 62 % of the reading for the average power for
4.1 A heated manikin is placed inside a sleeping bag or
the test period. Since there are a variety of devices and
sleeping bag system in a cold environmental chamber.
techniques used for power measurement, this standard does not
4.2 The power needed to maintain a constant body tempera-
provide specific calibration procedures. Develop and document
ture is measured. an appropriate power calibration procedure.
6.3 Equipment for Measuring the Manikin’s Skin
4.3 The total thermal insulation of the sleeping bag or
Temperature—The mean skin temperature shall be measured
sleeping bag system (including the resistance of the external air
with point sensors or distributed temperature sensors.
layer) is calculated based on the skin temperature and surface
6.3.1 Point Sensors—Point sensors shall be thermocouples,
area of the manikin, the air temperature, and the power level.
resistance temperature devices (RTDs), thermistors, or equiva-
lent sensors. Ensure that they are no more than 2 mm thick and
5. Significance and Use
are well bonded, both mechanically and thermally, to the
5.1 This test method can be used to quantify and compare
manikin’s surface. Bond lead wires to the surface or pass
the insulation provided by sleeping bags or sleeping bag
through the interior of the manikin, or both. Area-weight each
systems. It can be used for material and design evaluations.
sensor temperature when calculating the mean skin tempera-
ture for the body. If point sensors are used, a minimum of 11
5.2 The measurement of the insulation provided by clothing
point sensors are required. At least one sensor shall be placed
(see Test Method F1291, ISO 15831) and sleeping bags (ISO
on the head, chest, back, arms, legs, hands, and feet. These
23537) is complex and dependent on the apparatus and
sensors must be placed in the same position for each test, and
techniques used. It is not practical in a test method of this scope
the placement of the sensors shall be given in the report.
to establish details sufficient to cover all contingencies. It is
6.3.2 Distributed Sensors—If distributed sensors are used
feasible that departures from the instructions in this test method
(for example, resistance wire), then the sensors must be
will lead to significantly different test results. Technical knowl-
distributed over the surface so that all areas are equally
edge concerning the theory of heat transfer, temperature and air
weighted. If several such sensors are used to measure the
motion measurement, and testing practices is needed to evalu-
ate which departures from the instructions given in this test
method are significant. Standardization of the method reduces,
Information on laboratories with heated manikins can be obtained from the
but does not eliminate, the need for such technical knowledge.
Institute for Environmental Research, Kansas State University, Manhattan, KS
Any departures need to be reported with the results. 66506.
F1720 − 17 (2023)
temperature of different parts of the body, then their respective 8. Preparation of Sleeping Bags
temperatures need to be area-weighted when calculating the
8.1 The sleeping bag shall be the appropriate size for the
mean surface (skin) temperature. Distributed sensors must be
manikin with respect to its width and length. A bag that fits
less than 1 mm in diameter and firmly attached to the manikin
tightly and causes compression in the head, feet, or hip areas
surface at all points.
may have a lower insulation value than one that does not cause
6.4 Controlled Environmental Chamber—Place the manikin compression.
in a chamber at least 3 m by 2 m by 2.6 m in dimension that
8.2 Bags shall be tested prior to laund
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