ISO 23537 Requirements for Sleeping Bags

The “ISO 23537 Requirements for sleeping bags” standard, developed by the International Organization for Standardization (ISO), consists of the following sub-sections published under the same title:

The standard “ISO 23537-1 Part 1: Thermal, mass and size requirements for sleeping bags designed for limit temperatures of -20 degrees and above” describes the labeling requirements, test methods and other principles regarding the thermal properties, dimensions and mass of adult-sized sleeping bags intended for use in sports and leisure activities at limit temperatures of at least -20 degrees.

This standard includes a method for evaluating a sleeping bag's performance in steady-state conditions in terms of protection against cold.

Sleeping bags that lack a homogeneous filling designed to provide localized extra insulation in specific areas lead to problems during calibration or testing procedures. Work is ongoing to provide suitable methods for determining temperature ratings.

This standard does not apply to sleeping bags designed for specific purposes, such as military use and extreme climate zone expeditions. It does not apply to sleeping bags for children or infants. A predictive model for determining limit temperatures based on the thermal resistance of sleeping bags for children and infants does not exist. Furthermore, such a test model cannot be developed because, for ethical reasons, the necessary controlled sleep trials with children or infants in climate chambers are not feasible.

In principle, the thermal resistance of a sleeping bag is measured using a thermal mannequin placed inside the sleeping bag and exposed to a controlled atmosphere, meeting the requirements and test procedure of the ISO 15831 standard. Then, using this thermal resistance, a physiological model is applied to determine the ambient temperatures corresponding to the sleeping bag's usage range. This mannequin test is suitable for mummy-shaped sleeping bags that do not fit snugly on the mannequin. The temperature rating result can also be applied to mummy sleeping bags of other sizes using the same materials and insulation structure, but proportionally larger or smaller than the one being tested.

A thermal mannequin conforming to the ISO 15831 standard, with a body height of 1,70 m plus/minus 0,15 m, is used during the test. The mannequin wears the following clothing during the test:

Two-piece suit (long-sleeved top, trousers) with material specific heat resistance between 0,040 m2∙K/W and 0,060 m2∙K/W when tested according to ISO 11092 standard.
Knee-high socks with material specific heat resistance between 0,040 m2∙K/W and 0,060 mV∙K/W when tested according to ISO 11092 standard.

The thermal mannequin's skin temperature must conform to the ISO 15831 standard.

In short, the ISO 23537-1 standard focuses primarily on thermal performance (how warm the sleeping bag keeps you) in addition to weight and size specifications. The aim of this standard is to provide consumers with reliable, comparable, and standardized temperature ratings for sleeping bags. It uses a scientific, repeatable laboratory method to create objective ratings that better reflect real-world performance.

The essence of the standard is a thermal mannequin test (a heated, human-shaped mannequin) placed inside a sleeping bag in a controlled climate chamber. The test simulates realistic conditions, including:

A standard sleeping position
Controlled air movement (approximately 1 km/h airflow)
Specified ambient temperature
Measurement of heat loss.

This test determines four basic temperature values:

T comfort level: The lowest outside temperature at which a standard woman can sleep comfortably without feeling cold.
T-limit (Limit rating): The lowest outside temperature at which a standard male can sleep curled up for 8 hours without waking up from the cold (risk of slight shivering is acceptable).
T Extreme (Extra rating): Survival rating, the lowest temperature at which the risk of severe hypothermia begins, but the sleeping bag can prevent death for a short period.
T-transition (sometimes included): A transition zone between comfort and limit where most average users will feel cool but not yet uncomfortable.
The ISO 23537-2 Part 2: Fabric and material properties standard describes the fabric and material properties and labeling principles for adult-sized sleeping bags intended for use in sports and recreational activities. This standard does not apply to sleeping bags designed for specific purposes such as military use or extreme climate expeditions. It also does not apply to sleeping bags for children or infants.

The fabric combinations of the outer or inner lining of the sleeping bag must be tested according to the EN 12132-1 standard. The number of feather or down fibers counted should not exceed 10 for each fabric combination described in the EN 12132-1 standard. Synthetic fiber impermeability must be tested according to the EN 15586 standard. The number of synthetic fibers escaping from the outer or inner lining of the sleeping bag should not exceed 30 per pillow.

The fabric's abrasion resistance is tested according to ISO 12947-1 and ISO 12947-2 standards. The outer layer of sleeping bags must withstand at least 20.000 test cycles.

The tear properties of the fabric are tested according to the ISO 13937-1 standard. The tear strength of both the outer and inner fabrics must be at least 10 N.

The color fastness of the outer and inner fabrics is tested as follows:

Color fastness to wet and dry friction is tested according to the ISO 105-X12 standard. Staining should be at least 3-4 fastness level according to the ISO 105-A03 standard.
Color fastness to wash is tested according to ISO 105-C06 standard at the care label temperature. Color fastness and stain fastness should be at least 4 according to ISO 105-A03 standard.
Color fastness to perspiration is tested according to the ISO 105-E04 standard. Staining and discoloration should be at least a 3-4 fastness level according to the ISO 105-A03 standard.
Color fastness to light is tested according to the ISO 105-B02 standard. The color change should be at least 4-5 fastness level according to the ISO 105-B02 standard.

In short, the ISO 23537-2 standard focuses on the fabric and material properties of adult-sized sleeping bags, especially those designed for sports and recreational activities. This standard helps ensure that sleeping bags meet minimum quality, durability, safety, and performance criteria related to their outer and inner fabrics, fillings, and other materials. This standard specifies the following:

Required specifications for fabrics and other materials used in sleeping bags.
Test methods to verify compatibility.
Labeling requirements to ensure consumers receive clear, consistent, and reliable information.

The main areas covered by this standard are:

Down and synthetic fiber impermeability (conditions and test methods required to prevent filling material from escaping through the outer fabric).
Mechanical properties of fabrics (e.g., tensile strength, tear resistance).
Color fastness (resistance to abrasion, washing, and light according to standards such as ISO 105 series).
Dimensional stability and other fabric performance criteria.
Resistance to pilling, abrasion resistance, and similar durability properties where applicable.
Flammability or safety-related material properties.
Labeling requirements (mandatory information that must be present on the product or packaging, including material composition, care instructions, and compatibility references).
The “ISO 23537-3 Part 3: Sleeping bags for extreme conditions” standard is still under development.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services compliant with the ISO 23537 standard.