GORE TEX Pressure for Transmission of Liquid Water

This is news to me. How do you know this? What rate of transport are you thinking of? Sufficient pressure can rupture the material. I guess that will send liquid water through Gore Tex. That will depend on the material's strength, thickness and size of unsupported area, assuming it is backed up by some sort of mesh or perforated material.

What little I know about these permeable fabrics is that the holes are so small that water droplets won't fit through but water vapor- individual molecules- will. So water transport will be a combination of permeation through the body of the Gore Tex (extremely small but probably measureable with the right instrumentation) plus difusion through the holes in the material.

Water droplets or macro amounts of water will have an equilibrium pressure of water vapor in the vicinity of the surface. This is dependent on temperature not pressure. If water is in contact with Gore Tex I suppose the holes will be exposed to the equilibrium vapor pressure of water and difusion will occur. I don't see how pressurizing the water will increase this rate significantly.

Are you thinking of capillary flow? You can think how much pressure would force measureable capillary flow through the micro holes in Gore Tex. How could you prevent material failure at the very large pressure this would require if it is possible at all? Is this an opportunity for me to learn something new?

It's certainly an interesting topic.

Richard

Richard, yes, this is an opportunity for you to learn something new, or learn something decades old, as the case may be.

There is a test called "water entry pressure" or something similar.

It is used for various kinds of "waterproof" fabrics. Including regular coated nylon.

Sometimes it is expressed as the height of a water column needed to cause water to extrude through the micropores.

I had a Helley Hansen jacket rated at 20,000 mm.

If you look at the Columbia line of "waterproof and breathable" garmets, there is often a hang tag which lists both a water entry pressure number and a number that represents a "water vapor permeability" number.

There are different tests advocated by different people for the same thing, and there appears to yet be no US standard widely used in consumer goods.

Google is your friend for enlightenment.

Thanks. I guess I didn't read Bret's question from the right perspective.

Richard