AATCC TM 127 Water Resistance - Hydrostatic Pressure Test

The standard "AATCC TM 127 Water Resistance - Hydrostatic Pressure Test," published by the American Association of Textile Chemists and Colorists (AATCC), describes a test method for measuring a fabric's resistance to water penetration under hydrostatic pressure. This method is applicable to all fabric types, including those treated with water-resistant or water-repellent finishes.

Water resistance depends on the repellency of the fibers and yarns and the fabric structure. Results obtained with this method may not be the same as those obtained with AATCC methods against rain or water spray. This test method is performed without any restrictions. If a restriction is required, the AATCC standard "Water resistance - Hydrostatic pressure test using restrictions" should be used.

In principle, hydrostatic pressure is applied to one surface of the test specimen, increasing at a constant rate until three leakage points form on the other surface. Water can be applied from either the top or bottom of the test specimen. This test method is performed without any restrictions.

For the purposes of this standard, the following definitions apply:

• Hydrostatic pressure: The force exerted by water on an area.
• Water resistance: Refers to the fabric's ability to resist wetting and water penetration.
• Water repellency: It refers to the ability of a fabric, textile fiber, thread or fabric to resist wetting.

These tests use a hydrostatic tester and distilled or deionized water.

At least three fabric samples should be taken diagonally across the width of the fabric, representing the fabric's material. To ensure proper compression, the samples should be cut to a minimum of 200 mm x 200 mm. Handle the samples as small as possible, and avoid folding or contaminating the test area. Test samples should be air-conditioned for at least four hours before testing at a temperature of 21°C (plus/minus 2°C) and a relative humidity of 65% (plus/minus 5%). The surface of the fabric to be exposed to water should be indicated, as different results may be obtained on the front and back surfaces. This surface should be marked on one corner of each sample.

When performing the test, verify that the water in contact with the test sample is set at 21°C plus/minus 2°C. The clamping surface is dried. The sample is clamped with the surface to be tested facing the water.

Option 1 If using a hydrostatic pressure tester, start the engine, press the lever to raise the overflow device at a speed of 10 mm/s and close the vent as soon as water begins to flow.

Option 2 If using a hydrostatic pressure tester, select a gradient of 60 mbar/min (1 mbar/sec) and press the start button.

Ignoring the water droplets appearing approximately 3 mm from the sample compression ring, the hydrostatic pressure at the moment when the water droplets penetrate the fabric from three different places is recorded.

The average hydrostatic pressure is calculated for each sample.

The report to be prepared should include the following information:

• The results of each sample and the average of each sample.
• Material and side tested.
• Water temperature and type.
• Gradient (rate of increasing water pressure).
• The tester option used.
• Any changes made to the method.

In short, the AATCC TM 127 standard is a widely accepted test method used to evaluate the water repellency of textile fabrics. This test specifically determines a fabric's resistance to water penetration under hydrostatic pressure. It is a fundamental standard for evaluating waterproof or water-repellent materials used in outdoor clothing, tents, medical textiles, and protective clothing. This standard evaluates a fabric's resistance to water penetration when subjected to gradually increasing water pressure. This test is particularly important for determining the performance of coated, laminated, or treated textiles designed to keep users dry in wet conditions.

While interpreting the results,

• High hydrostatic pressure degree indicates strong water resistance and is preferred for waterproof materials.
• A lower rating indicates that the fabric is more permeable and may not perform well in heavy rain or prolonged exposure.

Results may vary depending on factors such as:

• Fabric and weaving type
• Coating or lamination
• Fabric tension during testing
• Wear and tear of textile materials

Industries based on the AATCC TM 127 standard include:

• Outdoor and performance wear (jackets, raincoats)
• Medical textile products (surgical gowns, drapes)
• Military equipment
• Tents and shelters
• Automotive and marine textiles

The key advantages of the AATCC TM 127 standard are:

• Provides quantitative measurement of water resistance
• It is a repeatable and standardized method
• Necessary for quality control and product development

This standard is considered important for the following reasons:

• Ensures functional performance: Many textile products are expected to perform in wet or harsh environments. For example,
  • Raincoats and outerwear should keep the wearer dry.
  • Tents and outerwear must prevent water infiltration.
  • Medical fabrics, such as surgical gowns, must be resistant to liquid penetration to protect patients and healthcare workers.

This standard objectively measures a fabric's water resistance, helping manufacturers verify that their products perform as intended.

• Supports quality control and product consistency: Using consistent and repeatable testing allows manufacturers to:
  • Maintaining quality between production batches
  • Detecting defects or inconsistencies in veneers or laminates
  • Objectively compare different fabric processes or suppliers

Without AATCC TM 127 and a similar standard, companies may rely on subjective or non-comparable testing.

• Provides comparable and measurable data: This standard produces measurable results and ensures:
  • Guides materials selection and engineering
  • Supports marketing claims
  • Helps brands comply with industry standards and regulatory certifications
• Compliant with industry and international standards: This standard is widely accepted in North America and closely aligned with other global standards such as ISO 811. This makes it a trusted standard for international trade, global product development, and multinational quality assurance programs.
• Critical to safety in technical textiles: Water resistance can be a vital issue in sectors like healthcare, defense, and emergency response. This standard helps ensure that materials used in protective clothing and barriers meet stringent performance thresholds.

As a result, the AATCC TM 127 standard is a vital standard for evaluating hydrostatic resistance in the textile industry, helping manufacturers ensure their products meet water repellency performance expectations. With the growing demand for high-performance textiles in both consumer and industrial applications, this test remains a cornerstone of textile quality assurance and innovation.

Our organization, which has been serving for many years and meticulously following global developments in science and technology, employs a skilled team and extensive infrastructure to conduct testing, measurement, and analysis in a wide range of areas for businesses across all sectors. In this context, we also provide testing services in accordance with the AATCC TM 127 Water Resistance - Hydrostatic Pressure Testing standard.