High-tech: It's not just for geeks

Dave and Mike will be hauling lots of high-tech gear on their expedition, but high-tech doesn't just refer to their computer equipment. They'll be relying on high-tech clothing to keep them warm and dry.

Can I get a GORE-TEX laptop?
While it’s true that high-tech has become a staple on extreme expeditions (just look at the MVS Mini-M satellite terminal, TRGpro palmtop, and Compaq Armada laptops we’re lugging to Nepal), nowhere is high-tech more apparent than in the clothes we’ll wear.

As recently as 1970, if you wanted to enjoy cold-weather activities, you had to dress in layers of polyester and wool. This was bulky, heavy when wet, and, let’s face it, the amount of time spent outdoors was directly proportional to the amount of water you absorbed into your clothes. I mean wool is great—after all, the great mountaineers of the past all wore wool—but it's bulky and when wet, can drag you down. Yes, I know wool insulates even when wet, but give me the weight issue. Alright?

Then, in 1976, we were given the gift of GORE-TEX. Folks, this is high-tech at its best. I know most of you out there have heard of the fabric, but I bet only a handful knows exactly what it is. And while I know there are other fabrics out there that can compete with GORE-TEX, I’m sticking to what I know best, and what has proven itself to me time and again.

GORE-TEX: A definition
For today’s science lesson, I’m going to tell you the story of GORE. The GORE-TEX membrane is a patented composite of two unique polymers. The first polymer, expanded polytetrafluoroethylene (that’s ePTFE for short), is a film containing nine billion pores per square inch. Each pore is 20,000 times smaller than a raindrop, but 700 times larger than a molecule of water. It is completely impervious to rain, snow, and sleet, and allows perspiration vapor to pass through. Vapor passing through is the key here. Remember those polyester and vinyl jackets that didn’t breathe? They were killers. After thirty minutes of hard exertion, you’d be sweating up a storm. Stop moving and you could almost feel the sweat turning to a thin layer of ice beneath your jacket.

But on with the lesson. The second polymer is an oleophobic ("oil hating") material that allows moisture vapor to pass through, but it blocks contamination from body oils, cosmetics, saltwater, and insect repellents that could otherwise affect water resistance. Pretty cool, huh? Next time you put on that GORE-TEX shell, have a little respect for those engineers, okay?

GORE-TEX fabric is made by laminating the GORE-TEX membrane to high-performance textiles selected for their suitability to the intended end use. Just as there are many types of outerwear for a variety of end uses, there are several types of GORE-TEX fabric to satisfy the requirements of different types of garments. Figures A and B illustrate two of those types.

Figure A
2-layer GORE-TEX

Figure B
3-layer GORE-TEX

Wet versus windy

So it’s one thing to stay dry, but how do you keep the wind out?

I’m glad you asked.

Windproof clothing works by preventing convective heat transfer. Convective heat loss is a significant factor in causing you to be, well, miserable. In cold, windy conditions, windproof clothing keeps you warmer by preventing convective heat loss (the wind-chill effect). Wearing windproof clothing prevents the displacement of warm air with cold air in the microclimate next to your skin. It’s like wearing a wet suit, only warm air is trapped next to your skin, not water. When wearing a windproof layer, you can maintain your warmth with less insulation in windy conditions. The benefit is greater warmth and comfort. WINDSTOPPER outerwear and accessories are made from highly air-permeable fabrics, such as knit or fleece fabrics laminated to the windproof WINDSTOPPER membrane.

My kingdom for a warm night’s sleep!

If you’ve ever been on an extended camping trip in cold weather, you know how important it is to get a good night’s sleep. Without that all-important REM stuff, the next day on the trail you’re feeling trashed by the third mile. Thankfully, Mr. Gore and Company have engineered something pretty remarkable.

Dryloft fabric is engineered specifically to enhance the performance of insulated garments and sleeping bags.

Heat loss in sleeping bags and clothing
Sleeping bags and insulated clothing keep you warm by containing the heat your body produces. The insulation literally traps pockets of "dead air," which is then heated by your body and is contained within the insulated clothing or sleeping bag. The three primary components of these products include the lining fabric, the insulation, and the shell fabric.

The shell fabric plays an important role in preventing heat loss via convection and conduction. The ideal shell fabric would be windproof and prevent water entry. That’s where Dryloft excels.

Dryloft fabric is a shell fabric that provides significant moisture protection. Because of the intricate construction of quilted or baffled sleeping bags or garments, it isn't practical or economical to seal the seams. However, greatly reducing the entry of moisture through the shell fabric is an effective way to reduce the onset of wet conductive heat loss. Dryloft fabric keeps the insulation dry from external moisture like condensation from tents or snow caves, dew, or even spilled coffee or soup.

A windproof barrier is crucial to maintaining the "dead air" within the insulation. When cold air passes through the shell fabric, it displaces the warmer air inside, and the temperature within the insulation is reduced. In addition, when you move or roll over in a sleeping bag with an air-permeable shell, you compress the insulation, and the warm air trapped in the insulation is literally pumped or squeezed out through the shell fabric. The warm air is replaced with cold air and more energy is required to reheat the system.

Breathability is a very important feature of shell fabrics. If there's an accumulation of moisture vapor within the insulation, condensation may occur. The more breathable the shell fabric, the less likely you are to develop condensation. Insulated products made with Dryloft fabrics retain their loft longer than products made with most other shell fabrics. The benefit is greater warmth and comfort.

Don’t mistake Dryloft for being completely waterproof—it's not. Wet weather demands truly waterproof, seam-sealed products or a tent.

Here endeth our lesson
That concludes today’s lesson on high-tech fabric. Like I said earlier, there are other competing fabrics out there, but for my buck, I’ll take Gore technology over all others. But that’s just my opinion. Have a high-tech recommendation of your own? I’d love to hear of it. Send me your thoughts.


And a special thanks to W.L. Gore & Associates, Inc. for allowing us to use images from their Web site.
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David Bard has been a fixture at TechRepublic for some time now. At one time he was editor-in-chief of LinuxRepublic and then AdminRepublic. Currently, he occupies space as an editor-in-chief with TechProGuild. In addition, he’s a freelance writer who has covered extreme sports for years. He also is a writer of horror and—contrary to what his climbing partner may think—is hoping the expedition to Nepal doesn’t provide fodder for his next story. When he’s not at home teaching his year-and-a-half-old daughter why it’s not a good idea to eat rocks, or trying to convince his wife why yet another expedition really is necessary, he’s usually off in some remote section of woods trying to discover himself. He’s still looking.

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