Hydrostatic Pressure Testing

Overview

Hydrostatic pressure…it sounds complicated. Is it? Not really. It’s just a test to find out how much pressure is required before a leak starts to occur. This test works on all types of fabrics, including those treated with a water-resistant or water-repellent finish.

Why do we test for water resistance?

Water resistance depends on the repellency of the fibers and yarns, as well as the fabric construction.

This test is important for fabrics that are used as a barrier in industrial applications. It’s an important test for products like rainwear, gowns, drapes, boat covers, and other barrier fabrics.

This test works on all types of fabrics, including those treated with a water-resistant or water-repellent finish.

Coated or laminated fabrics such as TVF’s nylon mid-weight waterproof breathable will have higher hydrostatic ratings than the fabrics only treated with a water-repellent finish, such as SunMaster. 

How does it work?

N

Step 1

The fabric is secured in a special testing machine.

N

Step 2

One surface of the fabric is subjected to hydrostatic pressure, increasing at a constant rate.

N

Step 3

When three points of leakage (water droplets) first appear, the test is stopped and the results are recorded.

The test is repeated at least three times and the results are averaged.

SunMaster has a hydrostatic head (HH) of 800+mm. This means that 800 mm of water could be accumulated in a column of water on SunMaster before any leakage would occur.

Note: A fabric with a waterproof breathable coating will have a much higher result.

Note: Excessive handling, folding, or contamination of the area to be tested might negatively affect the results of the test.

Tips from a TVF Expert

Remember, waterproofness is a function of the type and weight of coating and construction of the fabric.

The WPB fabric is much lighter and has a much tighter weave allowing for the coating to have better surface area coverage. Think of putting a coating over burlap versus a high count taffeta.

Lighter and tighter constructed fabrics need less coating weight to achieve the same performance of a heaver and looser weaved fabric.

We can also calender fabrics prior to coating to create a greater surface area and close the gaps between the intersecting points of each denier in order to achieve a higher rating with less coating or even higher rating with a greater amount of back coating.

AATCC 127 is a popular test because it more closely represents what happens in real world end-uses. Water is spread over a larger area with a lower rate of pressure.

Summary

The hydrostatic pressure test AATCC 127 tests what amount of pressure is needed to cause fabric to leak fluid. This could be a very important test for some industrial applications, depending on end-use.

0 0 votes
Article Rating

Join the Discussion

Have a question or additional knowledge – please share!

Subscribe
Notify of
0 Comments
Inline Feedbacks
View all comments
Post a comment

Leave a Comment

Join the Discussion

Have a question or additional knowledge – please share!

Your email address will not be published. Required fields are marked *

0
Would love your thoughts, please comment.x
()
x