ISO 25242:2026

ISO 25242:2026 is an International Standard from ISO for testing smart textiles systems under cyclic environmental temperature change. It specifies a laboratory method for checking how products such as electrically heated garments withstand rapid shifts between high and low ambient temperatures, with the focus on items that include the electrically operating part.

What does ISO 25242:2026 specify?

ISO 25242:2026 specifies an environmental test method for smart textiles systems exposed to rapid temperature changes. It is written for jacket, vest, jumper and similar products that include an electrically operating part.

The document is organized into seven clauses:

• Scope
• Normative references
• Terms and definitions
• Test equipment
• General requirements
• Test procedure, including specimen preparation, conditioning, cycling, recovery and run-time measurements
• Test report

Clause 6 is the core of the document. It sets out how to choose the test arrangement, how many specimens to use, how to condition and cycle them, and how to record run-time before, during and after the test. Clause 7 then states what information has to be reported so results can be compared and reviewed.

What are the key requirements of ISO 25242:2026?

ISO 25242:2026 focuses on a controlled temperature-change exposure and on comparing the system’s run-time before and after the test. In practice, the method is about repeating the same operating conditions, measuring the effect of the temperature cycling, and recording the outcome clearly.

Test equipment and set-up

The test equipment is an environmental chamber in accordance with IEC 60068-2-14 test Na, or Nc. The chamber has to house the specimen, allow measurement during conditioning, and hold the specified temperature within the required tolerances. For the reader, this means the chamber must support both the temperature shifts and the measurement activity without changing the test conditions.

Specimens and pre-test conditions

Clause 6.3 requires three test specimens per sample. The specimen is tested in an unpacked, switched-off, ready-for-use state, unless the operating conditions specify otherwise. Clause 6.6 requires conditioning at laboratory ambient conditions in the standard atmosphere from ISO 139, and the specimen is brought into operating condition when the relevant specification requires it.

Run-time measurements

ISO 25242:2026 requires a visual examination and electrical check before the first run-time measurement, as required by the relevant specification. The initial run-time is measured with the system at maximum performance conditions, and the average of the three specimens is recorded. The same approach is used for the in operation run-time during cycling and for the finished run-time after recovery. This gives a before-during-after comparison of how the system performs through the temperature stress.

Temperature cycling and recovery

Clause 6.8 defines one test cycle as a sequence from laboratory ambient to the first conditioning temperature, then to the second conditioning temperature, and back to laboratory ambient. The document uses the test cycle defined in IEC 60068-2-14 test Na or Nc. After cycling, the specimens are stored for at least 24 h in standard atmosphere conditions, unless the relevant specification sets a different recovery period.

Result calculation and reporting

Clause 6.12 defines a run-time change rate based on the initial and finished run-time. If the finished run-time cannot be obtained, the rate is not calculated. Clause 7 requires the report to identify the standard, the specimen, the test type, conditioning, mounting, temperatures, exposure time, number of cycles, measurements, recovery, deviations, observations and test date.

What terms does ISO 25242:2026 define?

ISO 25242:2026 defines the key terms used to interpret the run-time measurements.

• Smart textile system - a fabric that shows an intended and usable response to changes in its surroundings or to an external signal or input.
• Initial run-time - the elapsed time from system start with a fully charged auxiliary battery until battery discharge causes termination before cycling.
• In operation run-time - the elapsed time from system start with a fully charged auxiliary battery until battery discharge during the test.
• Finished run-time - the elapsed time from system start with a fully charged auxiliary battery until battery discharge after the test has been conducted.
• tinitial - the symbol used for initial run-time.
• tin operation - the symbol used for in operation run-time.
• tfinal - the symbol used for finished run-time.

Who uses ISO 25242:2026?

ISO 25242:2026 is used by laboratories, manufacturers, suppliers and quality teams working with smart textiles systems, especially electrically heated garments and similar wearable products. Test engineers use it to run environmental durability checks, quality managers use it to compare performance before and after temperature cycling, and buyers or customers use the reported results to review product robustness under storage, transport, installation and use conditions.

Which standards are used with ISO 25242:2026?

ISO 25242:2026 relies on two normative references and cites one related ISO document for terminology.

• ISO 139 - provides the standard atmospheres used for conditioning and testing.
• IEC 60068-2-14:2023 - provides the environmental test framework for change of temperature, including test Na and test Nc, and the chamber-related procedure used by this document.
• ISO/TR 23383:2020 - is cited as the source of the definition of smart textile system.

What does the ISO 25242:2026 document contain?

ISO 25242:2026 contains the full laboratory method, from specimen preparation through final reporting. It includes a table that aligns the test parameters for Na and Nc, a figure that illustrates the temperature cycle, and a formula for calculating the run-time change rate.

The document also sets out the practical steps for chamber preparation, specimen mounting or support, conditioning, initial measurement, cycling, in operation measurement, recovery and finished measurement. Clause 7 then lists the reporting items needed for traceable test records, including temperatures, exposure time, number of cycles, any deviation from procedure, and unusual observations.