Method for waterproofing fabric - Hydrostatic Head Test Method January 08 , 2020

The method for testing the waterproof performance of fabrics mainly includes hydrostatic head test method: one side of the fabric is subjected to hydrostatic pressure. When the hydrostatic pressure is gradually increased, and the other fabric is exuded, the water column height of the hydrostatic water indicates the water permeability of the fabric.This method is mainly to test the water permeability of the fabric.

To measure the water permeability or water repellency of a fabric, it is necessary to measure its water repellency or water conductivity. Different methods are used depending on the actual use of the fabric, and the water permeability or water repellency of the fabric is indicated by various corresponding indexes.

Hydrostatic head test method (fabric hydrostatic pressure tester)

Hydrostatic pressure refers to the ability of the fabric to seep under a certain water pressure. It is suitable for all kinds of fabrics, including those that have been waterproofed. The water repellency of the fabric is related to the water resistance of the fibers, yarns and fabric structures. The results are not the same as water spray and rain on the fabric surface. The water repellency of the fabric was measured by hydrostatic pressure method, and there were static pressure method and dynamic pressure method.

The hydrostatic method is to apply hydrostatic pressure on one side of the fabric, and measure the amount of water discharged under this hydrostatic pressure, the time of water drop, and the value of hydrostatic pressure at a certain amount of water. The hydrostatic pressure can be the height of the water column or the pressure. In the actual measurement, a per unit area and a permeation amount (mL / cm2 · h) per unit time are used. For waterproof fabrics, measure the time required for water droplets to appear on the other side of the sample, or observe the number of water droplets that appear on the other side after a certain period of time.

The principle of the dynamic pressure method is the same as the static pressure method, except that P is a variable. It is to apply a constant pressure of water pressure P on one side of the sample until the other side is penetrated by water to show a certain number of water drops, the imposed water pressure P. This method is more suitable for coated fabrics or tightly structured fabrics. Hydrostatic pressure is used to reflect the waterproof performance of fabrics. Fabrics with large hydrostatic pressure are highly waterproof, and fabrics with small hydrostatic pressure are weak. Water-repellent fabrics have a strong moisture absorption capacity. They are wet when exposed to water, have no water resistance, and do not produce hydrostatic pressure.

In the AATCC 127-2003 test method experiment, take at least three samples with a size and area of 200mm × 200mm along the diagonal direction of the sample to be tested. The water resistance of the two sides of the sample is different. Make a mark and test with (21 ± 2) ℃ distilled water. The test area is 100cm2. The test surface is in contact with water. The water pressure is increased at a speed of 60mbar / min (or 10mm / s). If there are water droplets leaking from three different places on the sample, the test reaches the end. However, water droplets leaking within 3mm from the sample holder are not effective. The measured result is the average of 3 test samples under the same conditions. The larger the test value, the greater the pressure value required for water to seep out of the sample, and the better its water resistance.

Recommended equipment: GT-C26A Hydrostatic Head Tester, GT-C26B High pressure-servo Hydrostatic Head Tester

GT-C26A Hydrostatic Head Tester

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