The odd bit of rain never hurt anyone (in a breathable, three-layer waterproof anorak)

Independent on Sunday, Sunday October 27, 2002

Many years ago, when I thought things like waterproof jackets didn't matter, I set off for a month long trek in south-west Tasmania. It was an intrepid venture, entailing an air-drop of supplies at the half way point, and I look back on the trip with fond memories. Beautiful, uncharted terrain, temperate rainforest stretching to the shores of the wild southern ocean, wombats and even a Tasmanian devil: it was all wonderful. Except for one thing.

Every time it rained, I got soaked through. It rains a lot in Tassie, and the thin blue nylon jacket I'd chosen was next to useless. Granted, the leeches only made it as far as my legs, but I was so drenched by the end of a day's walking that I half expected to find them nestling inside the folds of my jacket.

Back then, there wasn't a lot of choice. In contrast, today's walker faces such an array of waterproofs that simply deciding which one to buy can feel almost as demanding as a rain-lashed hike in the Pennines. It's all too tempting to abandon the burden of choice and conclude that a good old sou'wester will do the job.

Almost all of today's manufacturers claim their jackets are waterproof, windproof and breathable, and now one company, Páramo, says it has invented technology that is directional as well. The buzzwords are as bewildering as the myriad of options, but what do theymean?

A waterproof fabric is just that: it will keep you dry. There are degrees of waterproofing, as I well remember from my nylon jacket in Tasmania. In truth, this jacket was water resistant, rather than waterproof – it would initially displace water, only for it to soak through sooner or later. So too, with a little more fight, that good old sou'wester.

What my nylon jacket did not have was Gore-Tex. This fabric revolutionised mountaineering in the 1970s and now features in many quality outdoor garments. Gore-Tex is a thin, porous membrane that is bonded to fabrics like polyester and nylon. There are some 9 billion pores per square inch and at that size it's easy to see why water stays on the outside. Gore-Tex is 'breathable' too because the pores are large enough to allow molecules of water vapour (the sweat generated by working hard in the hills) to pass through. So a jacket that is breathable is one that passively passes moisture from your body back outside, aiding the body's natural cooling process.

Remember, though, as a salesman tries to convince you to buy that top-of-the-range Gore-Tex jacket, that there are different Gore-Tex laminates to satisfy the differing uses to which garments will be put. The Gore-Tex Paclite fabric, for example, weighs 15% less than a similar three layer Gore-Tex garment. Easy to pack and lightweight, it's ideal for climbing and mountaineering, but not quite the thing for a rainy weekend in the Cotswolds. Always ask exactly what the manufacturer designed the jacket for.

A good outdoor jacket should be windproof. This usually means that a fabric has a tightly woven layer of windproof laminate (often with breathable pores) sandwiched between two layers of fleece or nylon that the wind cannot penetrate. What, though, of a directional fabric?

Nick Brown, the managing director of Páramo Directional Clothing Systems, says that while 'the emphasis of our competitors is still on breathability, Páramo is more than just breathable.' Brown claims that his patented fabrics do not merely hold water back (waterproof) or passively pass moisture away (breathable), but actively 'direct' water as well as vapour to right spot, thereby allowing the body to maintain a steady and comfortable temperature.

Páramo uses its own unique 'Nikwax' fabric technology, all of which is organic and renewable. If the precise way in which the technology works remains a closely guarded secret, Major Mark Smyth, chairman of the Army Mountaineering Council for Germany and a mountain sports enthusiast, has no doubt that it works. "I have used Paramo gear in some of the most extreme and demanding environments on earth", says Smyth, "and have never been let down. The clothing is practical, warm and comfortable."

Impressive claims are also made by Sympatex Technologies for its patented Sympatex products. Sympatex guarantees that clothing featuring its material is 100% waterproof – not only that, but water repellent too. This means that the outer fabrics repel water to avoid becoming unnecessarily heavy, even if the wearer is dry inside. Sympatex itself is a non-porous laminate positioned so that the membrane is always the second layer behind the outer shell or face fabric. Depending on the intended end-use, the laminates can be made to be waterproof up to 180 p.s.i and more.

Nigel Shepherd, an internationally accredited mountain guide, has worn and tested any number of waterproof fabrics. He points out that whichever one you choose, suitable underclothing is vital. Make sure that you wear a good base layer to wick away perspiration moisture while retaining heat. The base layer should function like a second skin and will a have large say in how well the warmth and wind layers perform. You should also give the jacket a thorough 'road-test' in the shop. 'Don't assume that just because it looks good, it'll do the job', says Shepherd.

Check that it allows unrestricted movement by lifting your arms above your head and seeing how far the jacket rises. Check that the hood is adjustable, sturdy and spacious, and take a good look at the zips. They must be strong enough for heavy use and easy to operate, with two storm flaps, internal and external. Finally, ask whether the jacket has been tested at an independent test facility, whose endorsement will be more meaningful than that of the manaufacturer.

The good news is that most of the jackets on offer today are from pedigree companies, and the majority of them do what they say they will do. Manufacturers such as Karrimor, Sprayway, Berghaus and their reputable competitors either use 'traditional' Gore-Tex or equivalent technologies such as Sympatex. With Páramo making strides into previously uncharted technological territory, it's clear that we've come a long way from those thin blue nylon jackets that just never quite did the job.