Water Column

It determines the water impermeability of the fabrics.

Through a constant increment of the hydrostatic pressure, selectable between 0 and 600 cm/min, it determines the moment where it is possible to visibly see the passage of water in three points of the surface of the testes sample: in this moment it is possible to read the measure of the height of the water column (mmH2O) necessary to provoke the permeability of the fabric, according to the normative.

The sample to be examined is fixed through the suitable sealed system in a test area with a surface of 100 cm2. Equipped with an HMI – Touch screen panel for the maintenance and the monitoring of the tests, the configuration of the test parameters and the confirmation from the operator when the impermeability to water on the sample is reached. The saved results are filed with a backup inside the ROM memory (recoverable also in case of the stopping of the tool) for a maximum of 50 available tests.

Two methods of control are applicable: in case of constant hydrostatic pressure and in case of limit hydrostatic pressure:

a) Constant hydrostatic pressure, where the test proof is to verify the behavior of the tested specimen, for 24 hours, which undergoes a determined pressure which remains constant for all the testing time. After this period the obtained results to the inferior part of the specimen are verified and a relative judgment is expressed.

The inferior part of the fabric during the test:
is dry;
has produced overflowing or dripping, which interrupted before the end of the test;
had produced overflowing or dripping, which didn’t interrupt before the end of the test;

With this test it is possible to determine the level of effectiveness of the proceeding of permeability applied on the fabric.

b) Limit hydrostatic pressure. The behavior of the fabric is determined, subject to a gradually increasing hydrostatic pressure, understanding to what value of limit pressure the passage of water through the specimen takes place. The used tool is the previously described one: during the test, the level of water must grow of 1 cm of water column. It is possible to observe the fabric until the comparison of 3 water drops on the external surface. It is possible to note the pressure value indicated on the scale and this will be the impermeability value of the fabric.