Question conventional wisdom. We do every day. That kind of thinking led us to wonder: "Do we have to feel so clammy in our waterproof and so-called, "breathable" gear? Is it possible to stay dry without sacrificing comfort?" These questions led us to develop eVENT ® Fabric.
eVENT Fabric is a Direct Venting™ waterproof barrier that marks a significant advancement in ePTFE laminate technology. Using proprietary and patented Dry System™ technology, eVENT Fabric sets a new standard for comfort by allowing perspiration to dissipate and vent without saturating the inside of the fabric.
At the core of eVENT Fabric is an ePTFE (expanded Polytetrafluoroethylene) film that has been rendered oil-repellant, and thereby free from body-oil contamination, via a method that retains both the inherent open-pore structure of the membrane as well as its hydrophobic properties.
The eVENT family of fabrics are the smartest choice for athletes and adventurers who need and demand the highest possible performance and comfort from their apparel and footwear.
Most importantly, eVENT Fabric presents an improvement you will actually feel. For more information on how we determined this, read about our field-testing program.
Direct Venting™ vs. "Two-Step Moisture Transport"
Not only does eVENT® Fabric breathe at unprecedented levels - it does so in a different manner than existing waterproof/breathables.
Other waterproof/breathable technologies, including previous ePTFE technology, do not literally "breathe" but instead move moisture in two s-l-o-w steps by a process of diffusion through a polyurethane layer. In this process, perspiration vapour is first condensed into liquid form and is absorbed into the PU coating on the inside of the fabric. Then, body heat begins to push that dampness through to the outside of the fabric where it can finally evaporate. In this system, moisture vapour must condense into liquid in order to pass through the PU layer.
Because the anti-contamination treatment used in eVENT Fabrics does not cover the ePTFE membrane with a polyurethane coating, all the millions upon millions of pores in the material remain open, allowing them to breathe at their full potential. Sweated moisture vapour vents directly to the outside of the fabric in one easy step that we call Direct Venting.
At 5000x magnification, one can see the truly open-pore structure that is key to eVENT® fabric's unprecedented performance. Water from the outside cannot enter, but perspiration vapour from the inside can escape through the membrane's microscopic "nano" vents. This allows for a unique method of breathability that provides a huge and highly noticeable comfort advantage for the user.
Other waterproof fabrics, including others based on ePTFE membranes, contain a solid layer of polyurethane. These fabrics require perspiration vapour to condense into liquid and soak the PU-layer before enough body heat is generated to force that moisture through to the outside of the fabric. This method of "breathing" is not effective at providing noticeable comfort.
Dry System Technology™
Making a fabric waterproof is easy. Nothing to brag about. The real trick is making a waterproof fabric that doesn't cause you to soak in your own perspiration. Hence, all the fuss about "breathability". It's been over twenty years since the "breathability revolution" and improvements are still being measured only in percentages. Well, we believe that any argument about "level of breathability" is irrelevant if the inside of the fabric still gets damp and clammy during use.
How can a "wet system" keep you dry?
The expanded PTFE film that is used to make eVENT® Fabric cannot be used in raw form for waterproof applications because body oils, sweat, sun lotions, and even makeup will "contaminate" the material over time. These oils provide channels through which water can travel thus rendering the material somewhat less than waterproof. Therefore, to use ePTFE film for waterproof applications, it must somehow be rendered oil-repellant. Traditionally, this has been accomplished by putting a thin, continuous layer of polyurethane (PU) over the surface of the ePTFE to keep oils out. However, this solution creates two new problems. First, it immediately gives up much of the inherent breathability of the ePTFE because its open-pore structure is now covered. Second, because PU absorbs and retains moisture, the inside of the fabric quickly becomes, and remains, damp and clammy. We call this a "wet system". As we see it, the thing you're using to keep dry shouldn't be the reason you're always wet !
Finally. . . a Dry System!
The eVENT Fabrics advantage revolves around a patented method of rendering ePTFE oil-repellant without using a water-absorbing element like polyurethane and while retaining the open-pore structure inherent in the material. This is accomplished with a molecular surface treatment of the individual fibrils that comprise the open-pore structure of the ePTFE material. With this proprietary system - which we call Dry System technology - the moisture vapour you produce is not required to condense into liquid to escape the fabric. Instead, it is allowed to vent directly to the outside without first making the inside of the garment damp and clammy.