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暖暖阳光 发表于 2010-10-23 19:40
通常下雪时不下雨,20000mm防水有啥特殊需要, 还是不解?
Technical garments that used for high winter activity are designed so that snow and rain are not able to penetrate from the outside. When we ski our body generate sweat and heat results in a layer moisture being trap in between our body and the outer garment. If the garment has no breathability the moisture will stay in. When we slow down, says we stop wait for friends or for the chair lift this layer of moisture will cool down and make us feel cold. But if the garment has good breathability this moisture will escape to the outside. The reason why this garment has the ability to stop the element from the outside but able to wick it out from the inside is because these are tiny micro fabric being knitted so close together, the space or 'pocket' between this fabric are microscopic, so much smaller then the water molecule of snow and rain so they won't be able to get through. However perspiration has a water molecule much smaller that rain/snow so is able escape through the fabric.
However don't let the numbers fool you, not all technical garment are created equally. And realize most jacket will label 'water resistant xxxxxx mm' but not 'water proofing'. Technically speaking if a garment is 100% water proof then it'll have no breathability at all. A garment label as 10000 mm means it will withstand 10000 mm of rain fall over a 24 hr period. But most garment won't tell you under what water pressure. In fact most garment can only withstand a water pressure under light rain condition. And keep in mind if you have enough snow,especially wet snow stick and build up on your jacket it'll create a pressure heavy enough for the water molecule to eventually stink in. In heavy rain condition, most of these garments, even labeled as 20000 mm will not take long before it become saturated. Gor-tex, however can withstand a psi much higher then most other garments. That's why it's one of the most expensive. And also one of the few technical garment that was chosen to use for light to medium duty rain wear. At the end of the day you get what you paid for.
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