Jacket “Wet Out” Study:
“Wet Out” of waterproof breathable fabrics occurs when water saturates the jackets outer fabric layer above the waterproof/breathable layer, leaving the wearer feeling damp and clammy – as if the jacket were leaking – even if it’s not.
To prevent “wet out” waterproof breathable jackets and other clothes are treated with an ultra-thin “durable water repellent” (DWR) polymer. DWR penetrates the outer fabric fibers, lowering the surface tension of the fabric. This causes water to bead up and roll off instead of being absorbed.
However, DWR is not permanent. Regular wear, dirt, etc. shorten its lifespan. Once worn out, it can be reactivated by washing and drying the jacket. After the factory-applied DWR can no longer be reactivated, new DWR can be applied using a pump spray or wash in product. Nikwax TX-direct wash in is one product example.
To test jacket “wet out”, we set up the three jackets under equal pressure shower heads to observe overall water resistance and when/if the jackets would “wet out.”
Shower velocity for each shower head was equal, and measured at 992 cubic inches per minute – far greater than any naturally occurring rainfall.
As you see in the photo, the jackets were each set up in a scarecrow form. Under each jacket was a synthetic base layer. We weighed the base layers for wetness at 15 minute intervals. Specifically, every 15 minutes, we turned off the showers, removed the jackets, and weighed the base layers underneath.
We ran the test for 4 hours, and all the base layers stayed within 0.1 oz of their original weight over the 4 hours under the shower heads.
Practical Implications:
Each of the jackets tested was relatively new – none had been worn in the field, and the only work the jackets had completed prior to the “wet out” test was our breathability study above.
Next Steps:
Breathability – Gore-Tex fabrics dominate the market, and we’d hope this pilot study would help compare to the major competing fabrics of Neoshell and eVent. We did find a difference in performance, but the increase in room temperature and humidity for the eVent jacket test may have skewed our results. We’ll need to re-do the test and find a way to better control our environment.
Wet-Out – We’re not sure how to proceed here. What we did learn for sure from the 4-hour study is the factory-applied DWR of each jacket is effective under the test conditions.
But we’re not so interested in testing DWR as we are fabric differences. Somehow we’re going to need to test jackets with equal wear or with no factory-applied DWR.
Again, not sure how to proceed.
