I n the last few months you may have noticed that a new Gore-Tex membrane has begun to enter the market. But what's the difference between this new technology and those that the brand have used to date? Well it's complicated.
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At UKC/UKH we review products rather than testing them - by which I mean that we concentrate on how they perform as an end user out in the real world, not in a lab. But at the risk of getting academic, it's important to be aware of the background to the new Gore-Tex ePE membrane and its PFC-free DWR treatment if you're to understand why they have made the move, why brands are adopting it, and why it should be of interest and relevance to us when we next come around to buying a waterproof jacket.
ePE is as good as ePTFE for a damp day in Wester Ross© Dan Bailey
Before we delve into the detail it's worth starting with the basics, namely what is 'Gore-Tex'?
This waterproof/breathable fabric is not just a single layer, nor the name of the waterproof membrane itself; it's the name given to the whole package, which consists of several layers working together: the lining or backer, the membrane, and the face fabric.
Each layer has a distinct role:
In addition to these layers there is another which sits on the very top - the DWR (Durable Water Repellent) treatment. This plays a key role, providing a slippery layer on top of the face fabric which allows water to roll off it, as opposed to being absorbed by it - an effect known as 'beading'.
This treatment is not permanent, and once it's worn out a jacket's face fabric will begin to absorb water, whereupon it will 'wet out'. When a jacket wets out its breathability is reduced, meaning - in real terms - that you will start to feel the build-up of condensation on the inside. This dampness on the inside is often mistaken by the wearer as a membrane failure, but really it's just an indication that the DWR treatment needs refreshing (courtesy of a wash and proof with products such as Nikwax Tech Wash and TX Direct).
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Until recently Gore-Tex exclusively used an ePTFE (expanded polytetrafluoroethylene) membrane. This is the product that they've built a reputation on since it was first released in 1976, and the one that has ultimately made them the industry leader. Traditional ePTFE technology, and the DWR treatment that augments it, contain PFCs (fluorocarbons). These 'forever chemicals' don't break down and, in the case of DWRs, as a result of this they build up not just in the natural environment, but within living organisms too - ourselves included. The GORE-TEX membrane itself is not considered a health concern (as independently certified by Oeko-Tex and bluesign), as it is in a solid form and therefore does not break down in the environment. However, the negative health implications of this group of chemicals generally are nowadays better understood, and many industries - including the outdoor industry - are trying to reduce their use.
In response to a growing demand for PFC-free products from brands and end users, as well as in anticipation of changes to regulation, the company began the development ten years ago of ePE (expanded polyethylene). The result of this decade-long process is a completely new membrane, with a completely different structure. In tandem, Gore have also developed - and released - a PFC Free DWR treatment, which has been available since 2018, and is now used throughout 50% of their fabrics. Both these essential components of the waterproof/breathable fabric are PFC-free. Gore have also raised the bar in terms of using more sustainable materials, with both the backer and the face fabric of ePE jackets being constructed using recycled and/or solution dyed materials - the former reducing waste, the latter reducing the amount of water and energy required to make it.
On a practical level, ePE has a better strength to weight than ePTFE meaning that the membrane can be both lighter and thinner, which is part of the reason it has a lower carbon footprint. This gives jackets that feature ePE a slightly softer feel than their ePTFE equivalent. Most critical of all from a staying dry perspective, the ePE membrane has the same super high hydrostatic head, meaning it's equally suitable for the worst weather.
So far, so good for the planet. But there is an implication for the end user.
PFCs, awful though they may be, are extremely good at shedding water. Perhaps the most noticeable change for a wearer of any garment using PFC free DWR, will be the treatment's durability. This is simply not as effective, insofar as the 'durable' element of DWR is no longer as durable and the benefits don't last as long. But, on the bright side, the DWR treatment is significantly better for the environment.
Wet and windy wander on the wild side of Wyvis - a perfect chance to test the ePE membrane© Dan Bailey
Across the outdoor industry, the jackets of yesteryear (both Gore Tex and other brands) contained long-chain (C8) fluorocarbon based DWR treatments. These nasties were so effective at shedding water that you could get away without washing or proofing a jacket for a long, long time - in fact many people managed never to do so over a garment's lifespan. When the transition was made to a shorter-chain (C6) the most noticeable side effect in use was that your jacket's face fabric wetted out quicker, soaking up water rather than shedding it. While scientists continue to work on better solutions, with the currently available PFC-free DWR coatings the wetting out effect is unfortunately even more noticeable.
If your sleeve looks like the one on the right, you need to wash/proof your jacket© UKC Gear
The way around this is to wash and reproof your jacket more often. This may require a slight change in expectation and mindset on the part of end users.
In real world terms, you're going to have to wash and proof your ePE jacket more frequently, not because of its ePE membrane, but because its PFC-free DWR treatment will wear off quicker than the equivalent C6 PFC DWR would have. Obviously this requires time and effort to do, but the benefits - aside from a performance perspective - are numerous, not least that your jacket should last longer as a result of the extra TLC it's been given.
The current crop of ePTFE and ePE fabrics will coexist alongside each other for some time to come - for instance ePTFE membrane will continue to feature in Gore Pro products, as a result of it still being the most durably waterproof option available for now. ePE will take over where Gore Performance once dominated, with a broader appeal to the all-round outdoor enthusiast, but in the long-term Gore-Tex have acknowledged ePE membrane as being the future trajectory for the brand, as it aligns with their sustainability goals. No doubt they will keep working on its performance - much like they have the rest of the range over the last 45 years.
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UKC Articles and Gear Reviews by Rob Greenwood UKC REVIEW: Boreal Satori - an all round performer 28 May REVIEW: Black Diamond Vapor & Capitan Helmets 14 May DESTINATION GUIDE: Bridging Two Worlds: The Unlikely Connection Between Horses and Climbing 1 Apr PHOTOGRAPHY: UKC/UKH Photography Awards 2023 - Winners 15 Mar PHOTOGRAPHY: The North Face & Ellis Brigham Photography Awards 2023 - Category Finalists 16 Feb GROUP TEST: Performance Headtorches - Petzl Nao RL, Silva FREE and Black Diamond Distance 1500 2 Feb REVIEW: The North Face FUTUREFLEECE Hooded Jacket 24 Jan ARTICLE: The Role (and Reprisal) of the New Routes Book 19 Dec, 2023 REVIEW: Montane Phase Nano - The Ultimate Running Shell? 17 Nov, 2023 REVIEW: Patagonia Triolet Jacket - PFC-Free, and Built to Take Abuse 3 Nov, 2023 More Articles
Looking after our gear is one of the simplest ways to help reduce our environmental footprint; and it doesn't get much more fundamental than washing and reproofing waterproof clothing. Here we explain how to keep your shell performing at its best for longer.
Thanks, Rob Greenwood, for an excellent and fully comprehensive report on this issue.
Yesterday, I listened to a one-hour online product overview by Gore and Patagonia in Munich. This was very poor and full of self-congratulations.
Mike Parsons, OutdoorGearCoach ( I am a former WLGore licensee as Karrimor in the 90s!) ) We run cpd courses on PERFORMANCE LAYERING see next course Nov 20th Kendal wall
https://www.outdoorgearcoach.co.uk/blog/performance-layering-course-20-november-2023-kendal-climbing-wall/
Really good article, getting your head around fluorocarbon coatings is not easy! Yes PFC-free jackets are not as waterproof for as long, but they are still very good. My Alpkit Definition, one of the first to use PFC-free jacket that were in the market, has gone through 4 seasons of winter climbing without being re-proofed and it's still going strong.
Slightly off topic but how long should Goretex and eVent jackets last? If it's not damaged and I keep reproofing it should be 'forever'? I ask as my kit is around 13 years told (6 years of good steady use, 7 years of much less use) and I was wondering if I should be planning to replace?
"On a practical level, ePE has a better strength to weight than ePTFE meaning that the membrane can be both lighter and thinner Most critical of all from a staying dry perspective, the ePE membrane has the same super high hydrostatic head, meaning it's equally suitable for the worst weather."
"ePTFE membrane will continue to feature in Gore Pro products, as a result of it still being the most durably waterproof option available for now."
Hmmmm seems to be a contradiction here! ePE is as good....oh, ePE isn't as good.
100% Eptfe Membrane In my experience, goretex is fine until it starts to delaminate and you see 'blisters' on the face material. I suspect the type of goretex makes a difference (face material, 2 or 3 layer etc. and my 3 layer breathables have always lasted better than 2 layer ones without a protective inner layer - the membrane material has decomposed relatively quickly in those garments.