The waterproof index of the jacket
Waterproof index of jacket
Jackets, the foreign name is Jackets, also known as OutdoorJackets, transliterated as jacket, one of the essential equipment for outdoor sports. The reason why jackets have become the first choice outerwear for all outdoor enthusiasts is due to their all-weather functionality. The English name of Jackets is “Jackets” or “Outdoor Jackets”, which literally means “jackets”. Jackets are not mysterious, they are just jackets. However, when this kind of functional clothing was introduced to China from abroad, Chinese people wanted to distinguish it from ordinary clothes. , starting from its “free translation”, it is called “jacket”.
Because jackets have long been used when climbing high-altitude snow-capped mountains. When there are still 2-3 hours away from the summit, you will take off your down jacket, remove your big backpack, and move forward lightly wearing only a jacket. This is the Chinese name The origin of.
It is normal to encounter rain outdoors. For outdoor sports enthusiasts, a jacket with good waterproof function is a must-have equipment. The waterproof performance of a jacket is closely related to its waterproof index.
The so-called professional waterproofing of clothes means that whether you are sitting in a humid place or walking in a windy and rainy environment, it can effectively block the intrusion of rain, frost and snow, preventing water from penetrating into the clothes and making you feel damp and cold; The so-called breathability means that when you engage in heavy outdoor exercise, your body naturally sweats and your skin exhales a large amount of moisture. If it cannot be quickly discharged from the body, the sweat will be trapped between the body and the clothes, making you soaked. In rainy weather, people will feel more humid and cold. Especially in severe cold conditions such as mountains and canyons, body coldness and hypothermia are very dangerous, so good breathability of clothing is very important.
The so-called windproof refers to 100% prevention of wind cooling effect. In a changeable natural environment, when cold wind penetrates our clothes, it will blow away a layer of warm air near our skin. This layer of warm air is about one centimeter thick, with a temperature of 34 degrees to 35 degrees and a humidity of 40 degrees. Between %-60%. Even the smallest change in this layer of warm air can make us feel cold and uncomfortable. When cold wind blows into clothes, destroying this layer of warm air, causing rapid loss of heat and lowering body temperature, we will immediately feel the slightest chill. This is the so-called wind cooling effect.
Let us briefly understand this index first. Their unit is millimeters of water column pressure. The usual explanation is that when a 10,000mm high water column presses on the fabric and no more than 3 drops of water seep out of the fabric within 24 hours, then we think The waterproof index of this dress is 10000mm.
So the following question arises, what is the difference between 3000mm, 6000mm waterproof pressure and 10000mm waterproof pressure? Which type of jacket should I buy? It goes without saying that the higher the waterproof index, the stronger the waterproof performance, and of course the higher the price. The key to choosing a jacket under certain specifications depends on your actual needs. The one that suits you is the best. If it is only used for inter-city travel and daily outdoor wear, a waterproof index of 3000mm to 5000mm is enough; if it is for quasi-professional outdoor hiking, camping or crossing activities, a jacket with a waterproof index of 6000mm to 8000mm is enough to cope with it; but if If you need to go to an environment with difficult natural conditions for professional mountain climbing, adventure and other outdoor activities, it is best to choose jackets and pants with a waterproof index of 10000mm or above.
We often hear that – ah, the rainproof index of this jacket is 6000, and the rainproof index of that jacket is 10000. The units of 6000 and 10000 here are millimeters of water column pressure. The usual explanation is that when a 10,000mm high water column presses on the fabric and no more than 3 drops of water seep out of the fabric within 24 hours, then we consider the waterproof index of this piece of clothing to be 10,000mm. So someone asked, what is the difference between 6000mm waterproof pressure and 10000mm waterproof pressure? Which type of jacket should I buy? Wait for similar questions. Well, let’s start from the beginning.
The ending speed of raindrops
If there is no air (resistance), the clouds in the sky turn into rain and fall. After accelerating all the way, the speed when reaching the ground will reach 300 meters/second. This speed is basically equivalent to half the speed of a bullet. There would be no living creatures at all on land. Thank God, due to the existence of air resistance, when the raindrops form and start to fall, after a short period of variable acceleration (the acceleration gradually becomes smaller), when the air resistance encountered by the raindrops is equal to its own gravity, ok, at this time, the raindrops begin to move at a constant speed. Falling phase until reaching the ground. In physics, this uniform speed is called the closing speed of an object.
Size of raindrops
Some people have concluded that under normal circumstances, the diameter of raindrops is between 0.5mm and 6mm. In rare cases, the diameter of raindrops can reach 8mm or even 10mm (observed in the Hawaiian Islands).
Scientists have found that if water particles are smaller than 0.5mm, then due to the effect of atmospheric updrafts, water particles of this size can be kept in the air. The size of raindrops generally does not exceed 6mm. Due to the existence of air resistance, large raindrops often break down into many small raindrops whose volume decreases sharply during the falling process. In addition, these large raindrops constantly collide with each other as they fall, causing them to fall apart. Scientists have discovered that under laboratory conditions, large…The droplets usually begin to disintegrate when they reach about 5 millimeters in diameter. In clouds, when the diameter of large raindrops reaches 5 mm, they usually break up due to collision with each other. This is why it is rare to see raindrops with a diameter of 5 mm or more on the ground, because raindrops cannot avoid the fate of colliding with many others of their kind.
Raindrop size and ending speed
The ending speed of raindrops has a strong correlation with the size of the raindrops. Generally speaking, the ending speed of drizzle (diameter 0.5mm) is 2 meters/second, while the ending speed of heavy rain (raindrop diameter about 5.5mm) is 8~9 meters/second.
Finishing speed and water column height
With the ending speed, we can know the kinetic energy behind the raindrops. The kinetic energy and potential energy conversion formula of junior high school physics is enough to answer the relationship between the ending speed and the height of the water column. That is: 0.5MV^2=MgH, substituting the ending speed, we can get: when the ending speed of the raindrop is 8 meters/second, H=3.2 meters; when the ending speed of the raindrop is 9 meters/second, H=4.05 meters; the ending speed of the raindrop When it is 2 meters/second, H=0.2 meters;
Conclusion
Taking into account some factors (wetting, increasing thickness to extend the service life of the waterproof membrane, etc.), if it is only used for intercity travel and daily outdoor wear, the 6000mm waterproof index jacket is enough to cope with it. But if you need to go to a more difficult environment, it is best to choose jackets and pants with a waterproof index of 10,000mm or more.
Maintenance
Although most travel enthusiasts have their own favorite jackets, jackets are not as easy to clean as hiking boots. If you don’t take them seriously, you may waste a good jacket and have to spend money to buy it. So we have introduced it before Now that we have some basic knowledge about jackets, the editor will explain to you the washing and maintenance methods of jackets:
1. Maintenance when wearing
The quality of the jacket is relatively durable compared to ordinary clothing, but no matter how good the quality is, the waterproof and breathable layer of the jacket will gradually wear out and age as the wearing time increases. Therefore, in daily wear, pay attention to protecting the jacket. When traveling outdoors, do not let the backpack squeeze the jacket for a long time, because long-term squeezing and wear will accelerate the wear of the waterproof and breathable membrane of the jacket. You should pull the skirt of the jacket above the belt and then buckle the belt, so that it can effectively Avoid the wear and tear of the jacket caused by backpack straps.
2. Stacking of Jackets
When you are not wearing your jacket, you should put the jacket on a hanger and put it in the closet. You should not stack the jacket in the closet with ordinary clothes. This can easily cause the jacket to become full of lines and lose its straightness. And it is easy for the pleated parts to be worn, thus affecting the breathability and waterproof performance of the jacket.
3. Jackets should be cleaned appropriately according to the situation
This may be an issue that everyone easily overlooks. Although a jacket is relatively resistant to dirt, when the jacket is worn for a period of time, the surface will inevitably be stained with dirt or be wetted by acidic rain. At this time, if Not only do you need to wear a jacket, you should also clean it.
The breathable and waterproof performance of the jacket is mainly due to a layer of waterproof and breathable membrane in its fabric. This membrane is loose and porous, which can isolate water droplets and allow gas to pass through. However, if the jacket is stained with mud or oil, the dirt will block the gaps in the waterproof and breathable membrane, which will reduce the breathability of the jacket. In addition, there are certain acidic corrosive substances in rainwater, which can easily accelerate the aging of fabrics. Therefore, in this case, the jacket needs to be cleaned.
4. Do not wash your jacket frequently
This seems to be somewhat contradictory to the previous article, but it is not the case. Jackets should be cleaned according to the situation. There are two situations: after wearing for outdoor travel, it is covered with mud, oil, or after being exposed to rain; the second situation The situation is when the jacket is not worn for a long time. If it is neither of these two situations and is just for daily wear, you should not treat the jacket like ordinary clothing and wash it after only wearing it for a week. Although the correct cleaning method can avoid damage to the jacket, it is not suitable for heavy-duty use of the jacket. For clothes made of rubber, frequent cleaning is still very harmful. We should judge whether it is time to wash the jacket based on the degree of soiling after wearing it, not based on the length of time it was worn. eXLTjHO9
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