Dan Bailey and fellow outdoor journalists were recently invited to visit Gore’s snazzy factory in Livingston, Scotland, where Gore-Tex fabrics are assembled and finished garments are put through a rigorous testing regime.
hese days it’s a nice surprise to find any outdoor gear being made in the UK, and more surprising still is the high tech feel and sheer size of W.L.Gore’s Livingston plant, one of a handful worldwide where the company produces and tests its laminated waterproof/breathable fabrics. Boasting sales of $3billion in 2012, Gore is a huge global concern, with separate product divisions for electronics, industrial parts, medical products and fabrics. All are made using PTFE (Polytetrafluoroethylene) in various guises, but as I’m already out of my depth here I’ll stick with 'GORE-TEX' as used on the hill.
Originally evolving out of the development of plumber’s tape, Gore-Tex is a membrane of stretched (or ‘expanded’) PTFE, riddled with over 1.4 billion micropores per square centimetre.
It’s waterproof because these pores are roughly 20,000 times smaller than a water droplet; yet at the same time it’s breathable since the pores are about 700 times larger than a water vapour molecule.
In short, rain cannot penetrate but sweat can escape, a process driven by the difference between body heat inside the garment and a lower temperature outside.
This white filmy membrane is laminated onto a tougher face fabric and, typically, a backer, to protect it from dirt, grease and abrasion. In the Livingston factory these component layers are selected in batches from huge rolls of material, then fused together. To prevent the face fabric from ‘wetting out’ a DWR (Durable Water Repellent) fluorocarbon coating is then applied in a bath before being baked on in an oven to produce the final product ready to be shipped to garment factories worldwide (OK, mostly in China). This is all done under conditions of stable temperature and humidity for consistent results.
It sounds impressive, and I’m sure it is, but so jealously guarded are the details of the production line that members of the outdoor press are not allowed to witness every stage. Instead we’re shepherded from the shop floor to the adjacent labs.
Here they carry out the next stage in the process, the all-important inspection and testing - and it’s immediately clear that Gore take this as seriously as manufacture. Testing involves several stages, from a visual inspection for faults on the membrane and face fabric, through the industry standard MVTR test for breathability, and a spell in a wet lab, to checking the seam tape. Every batch of fabric is then put through its paces in a series of machines designed to mimic as closely as possible the stresses it’ll be under in real end use – stretching, tearing, twisting and rubbing with rough pads to check abrasion resistance. Each test is repeated for thousands of cycles.
But Gore’s involvement does not end with a batch of fabric. As a condition of supplying Gore-Tex to manufacturers they also inspect the factories where clothing and footwear are put together, to help ensure high standards. They even offer product support through the design process.
From trainers to gloves, Gore systematically test every product that’s made with Gore-Tex; boots are put through hundreds of thousands of flexes and then checked for waterproofness, whilst clothing is subjected to the ‘rain tower’ - a glass walled chamber a bit like a car wash, where a mannequin dolled up in the latest bit of rainwear is showered from above (that’s ‘rain’ at 76mm per hour) and sprayed from the side with horizontal jets (‘storm’). None of the assembled journalists volunteered to replace the dummy...
To help simplify people’s choice of garment Gore-Tex products have been divided into three classes based on end use, each employing a slightly different combination of fabrics:
|Gore-Tex||Gore-Tex Active||Gore-Tex Pro|
|This is the common or garden variety for everyday general purpose use in less committing environments, with moderate wear and tear and moderate exertion. Think walking the dog in the rain, or an average UK hillwalking day in summer. It's medium breathable and middle of the range for ruggedness – a jack of all trades.||For high aerobic activity in cool, mixed weather, this is Gore’s lightest and most breathable fabric. Ideal for runners, say - high performance but it’s not really built to last. Gore insist on simple, lightweight designs for all garments using this fabric, and a minimum of (non-breathable) seam tape.|
Here’s the stuff best suited to more serious winter walkers, mountaineers and climbers. It is very breathable and as rugged as Gore-Tex gets, for working hard in rigorous environments and extreme rain, snow and ice.
A revised version of Gore-Tex Pro hits the shops winter 2013/14, having been adopted by many of the leading gear companies. Gore reckon it’s their most robust fabric ever. It features a new multilayer membrane system with a 100% ePTFE-based microstructure, durably bonded to the outer material. This does away with the PU layer typically used in membranes, helping to boost the breathability by as much as 28% over the previous version of Gore-Tex Pro, according to Gore’s lab results. Only tougher face textiles (>40 denier) are allowed, and there’s a pretty demanding garment design specification too, to help with performance and ruggedness. Inside is Gore’s new ripstop Micro Grid Backer for high internal abrasion and snag resistance.
‘The endurance tests that we have conducted with several mountain guides have enabled us to assess the long lasting functionality of these products in the kind of conditions that outdoor enthusiasts will typically encounter on their tours’ says Tom Gray, product specialist at Gore.
We’ve yet to put the new Gore-Tex Pro through its paces, so watch this space...
See this product at the Ellis Brigham shop