The ISO 811 Hydrostatic Head Tester is a device designed to determine the water resistance of fabrics. It works by applying static water pressure to the test sample and observing the penetration of water to determine the degree of water repellency of the fabric.

The specific operation process is as follows:

Step 1: Prepare the test sample and place it on the tester.

Step 2: Fill the tester with water until the water surface height is higher than the test sample.

Step 3: Open the valve of the tester and slowly apply pressure so that the water pressure is applied to the test sample as evenly as possible.

Step 4: Observe the penetration of water on the test sample, and record the water surface height when the water penetrates the test sample.

Step 5: Calculate the hydrostatic head of the test sample based on the recorded data.

The above is the working principle and operation procedure of ISO 811 Hydrostatic Head Tester. With this device, the waterproofness of fabrics can be accurately determined, providing an important reference for the production and manufacture of various waterproof products.