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, is an internationally recognized method for quantifying the thermal insulation performance of sleeping bags and sleeping bag systems. Developed by ASTM International, this standard is critical for manufacturers, researchers, and regulators concerned with outdoor equipment safety, quality, and performance. The test employs a heated, life-size manikin to assess resistance to dry heat transfer in controlled cold environments. Results provide a reliable basis for comparing different bag designs and supporting claims related to comfort and safety.

Key Topics

• Thermal Insulation Measurement: The method uses a constant skin temperature manikin within a sleeping bag or system, placed in a controlled cold environment. It assesses the insulation by measuring the power required to maintain the manikin's skin temperature and calculating the thermal resistance, commonly expressed in clo units.
• Standardized Conditions: Test conditions include air temperature, velocity, and humidity, as well as detailed manikin specifications (e.g., surface temperature, size, and shape) to ensure reproducibility across tests.
• Reproducibility: Although the method generates reproducible data, the manikin cannot perfectly replicate human sleep behaviors or all environmental influences affecting real-world use. All deviations or special conditions must be reported in the results.
• Testing Setups and Options: The standard details procedures for testing single sleeping bags as well as more complex sleeping bag systems, which may include clothing, ground pads, and other auxiliary items. This allows assessments both of product materials and complete sleep systems.
• Reporting Requirements: Reports must describe the bag(s) and any auxiliary products, environmental conditions, calibration details, insulation values, and any deviations from standard procedures.

Applications

• Product Development: Designers and manufacturers of sleeping bags use this method to evaluate and optimize materials and construction for thermal performance, supporting innovation and product improvement.
• Quality Assurance: The test provides objective criteria for quality control-critical for brands, retailers, and procurement authorities (such as military suppliers) to ensure products meet thermal performance requirements.
• Regulatory Compliance and Marketing: Results documented under this standard can support temperature rating claims in line with international expectations, assisting with compliance and consumer communications.
• Comparative Analysis: By enabling side-by-side thermal insulation comparisons between products or systems, the test supports purchasing decisions and benchmarking studies within the outdoor equipment market.
• Safety and Comfort Validation: Accurate insulation data is essential to ensure user comfort and minimize risk of cold exposure, especially in extreme outdoor conditions.

Related Standards

Employing ASTM F1720-17(2023) in conjunction with other standards enhances the reliability and comparability of thermal insulation testing:

• ASTM F1291: Standard Test Method for Measuring the Thermal Insulation of Clothing Using a Heated Manikin – for clothing system evaluations.
• ISO 15831: Clothing - Physiological effects - Measurement of thermal insulation by means of a thermal manikin.
• ISO 23537: Requirements for Sleeping Bags – provides guidelines for both thermal and dimensional requirements for sleeping bags.

By adhering to ASTM F1720-17(2023) alongside these related documents, stakeholders can ensure accurate, high-quality, and internationally comparable results throughout the supply chain. This approach supports both consumer safety and product integrity within the outdoor and camping industry.

Keywords: ASTM F1720-17, sleeping bag insulation, heated manikin, thermal resistance, outdoor equipment testing, clo units, sleeping bag system, quality assurance, standard test method, outdoor safety.

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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