ISO 25243:2026

ISO 25243:2026 is an International Standard from the International Organization for Standardization (ISO) for testing smart textile systems under repeated underwater pressurization. It specifies a laboratory method for checking whether a smart textile system can withstand high pressure conditions in underwater applications.

It is written for engineers, quality teams, test laboratories, and buyers who need a repeatable way to assess underwater durability and compare products on the same basis.

What does ISO 25243:2026 specify?

ISO 25243:2026 specifies a test method for smart textile systems used in underwater applications. It is organized as scope, normative references, terms and definitions, apparatus, general requirements, test procedure, and test report.

The standard is focused on one performance question: how a smart textile system behaves after repeated pressurization in water. In practice, this helps users verify whether a product still operates after exposure to a controlled underwater pressure cycle.

What are the key requirements of ISO 25243:2026?

ISO 25243:2026 defines the test set-up, the specimen condition, the pressure cycle, and the way results are recorded. The most important points are below.

Apparatus and test set-up

Clause 4 requires an immersion tank in accordance with EN 14225-1. The tank must be able to deliver at least 6 bar and be large enough to accommodate the smart textile system being tested.

This matters because the pressure chamber and its fit to the specimen can affect whether the test is repeatable and whether the product is exposed to the intended underwater conditions.

Specimen preparation and initial measurement

Clause 5 requires the operating instructions and all parts needed for connection to be available for testing. Unless otherwise specified, all parts are connected during the test.

Clause 6.1 calls for three test specimens per sample. The specimen is tested either unpacked, switched off, and ready for use, or in the operating state specified for the product.

Clause 6.2 measures the initial run-time after conditioning in the standard atmosphere given in ISO 139, then setting the specimen to maximum performance conditions. The average of the three specimens is recorded.

This gives a baseline before water exposure, so the final result can be compared with the same product under the same starting conditions.

Pressure exposure and drying

Clause 6.3 is the durability test. The specimen is disconnected from the power source, fully submerged, and subjected to ten continuous pressure cycles in water at (6 ± 0,18) bar absolute and (20 ± 2) °C.

Each cycle consists of:

• pressure increase over 3 min ± 10 s
• pressure hold for 10 min ± 10 s
• pressure release over 5 min ± 10 s

Clause 6.4 then requires drying on a horizontal screen drying rack, using flat drip dry as described in ISO 6330, followed by at least 24 h in the standard atmosphere of ISO 139.

This is important because the product is measured again only after a controlled recovery period, not immediately after removal from water.

Finished measurement and result calculation

Clause 6.4.2 repeats the run-time measurement after the test and requires the average of the three specimens. If one or more specimens do not work normally, the document requires the relevant information to be recorded and the finished run-time not to be calculated.

Clause 6.5 defines the rate of change as the run-time change expressed as a percentage of the initial run-time. In practice, this gives a simple way to show how much performance changed after repeated pressurization.

Test report

Clause 7 requires the report to identify the standard used, the tested smart textile system, the test conditions, the initial and finished run-times, the rate of change, any appearance changes, deviations from procedure, unusual features, and the test date.

This makes the result traceable for quality records, supplier evaluation, and product comparison.

What terms does ISO 25243:2026 define?

• Smart textile system - a fabric that gives an intended and usable response to changes in its surroundings or to an external signal or input.
• Initial run-time - the time from starting operation with a fully charged auxiliary battery until discharge ends operation, before the durability test.
• Finished run-time - the same operating time measurement taken after the durability test and drying.
• t_initial - the symbol used for initial run-time in the document.
• t_final - the symbol used for finished run-time in the document.

Who uses ISO 25243:2026?

ISO 25243:2026 is used by developers and manufacturers of smart textile systems, especially for underwater or high-pressure applications. It also supports test laboratories, quality managers, and buyers who need a common method for checking durability and comparing performance after pressure exposure.

The standard is also relevant to teams working with e-textiles, because the introduction describes these products as being used in extreme environmental conditions.

Which standards are used with ISO 25243:2026?

• ISO 139 - provides the standard atmospheres used for conditioning and testing, including the temperature and relative humidity conditions used for run-time measurement.
• ISO 6330 - provides the flat drip dry procedure used for drying the specimens after immersion.
• EN 14225-1 - provides the immersion tank requirements and the underwater test conditions referenced for the pressure test.

What does the ISO 25243:2026 document contain?

The document contains one worked test method built around run-time measurement before and after repeated underwater pressurization. It includes an apparatus clause, a general requirements clause, a detailed procedure for sampling, conditioning, pressure cycling, drying, and post-test measurement, and a reporting clause.

It also includes one calculation in clause 6.5 for expressing the change in run-time as a percentage. The bibliography points to ISO/TR 23383:2020 for definitions, categorisation, applications, and standardization needs related to smart textiles.