Modern mountaineering rope is designed and produced according to the requirements of modern mountaineering. All climbing ropes are made of a net with a layer of outer net on the outside of several strands of twisted rope, instead of ordinary nylon rope. According to the different requirements of use, there are mainly two kinds of wear resistance and friction, and the outer net of climbing rope is also divided into two kinds of single weave or double weave. Generally speaking, the friction of climbing rope with single woven outer net is smaller and wear-resistant. There are various colors of climbing rope. Generally speaking, the rope used by different members of the same climbing team should be crossed so as not to lose in technical operation.
The manufacturer divides the rope into two categories: power rope and static rope. Static ropes can't absorb impulse by stretching and are more durable than power ropes. It is generally used as the fixed rope for cave exploration, rescue and mountaineering. Now it is also often used in high-altitude speed drop. The static rope is designed to be as small as possible in elasticity, so it can hardly absorb large impact force, so it is generally not used as the falling protection rope. The power rope can stretch and absorb the impact generated by falling, and it is autocratic for falling protection. The power rope (main rope) is the core of the whole climbing protection system. Compared with the static rope, which depends on its durable life and strength, the buyer of power rope pays more attention to the weight and impact times of power rope. The power rope has excellent elongation. Although it can absorb the impact force, if it is applied to the unsuitable use environment wrongly, the elongation of the power rope will produce up and down shaking similar to the spring property, which will also cause unnecessary trouble to the user.
The modern rope consists of a core and a jacket, which protects the rope from wear. The length of the rope is generally measured in meters. The current 55 and 60 meter ropes have replaced the past 50 meters. Although the long rope is heavier, it can climb the longer cliff. The manufacturer usually manufactures 50,55,60,70 meters in length. The diameter is usually expressed in mm. Fifteen years ago, 11 mm diameter was popular. Now 10.5mm and 10 mm. Even some single ropes have diameters of 9.6 and 9.6 mm. The rope with large diameter has good safety factor and durability. String is generally used for mountain climbing protection. The weight is generally calculated in grams per meter. Weight is a better index than diameter. Don't go for light but choose rope with small diameter.
The International Union of mountaineering associations (uiaa) is the authority to develop rope testing standards. The standard of dropping uiaa to test the strength of rope is called dropping test. 80 kg weight for single rope test. During the test, fix one end of the rope to make the 9.2-foot rope drop 16.4-foot total height. This produces a 1.8 drop index (the vertical height of the drop divided by the length of the rope). The worst drop index in theory is 2. The higher the drop index, the more limited the impact energy absorbed by the rope. In the test, the 80 kg weight dropped over and over until the rope broke. The environment of uiaa drop test is stricter than that of real climbing. If the number of drops in the test is 7, it doesn't mean you have to throw it away after 7 drops in practice.
But if the length of the falling rope is too long, you have to consider throwing it away. The impact force should also be considered in the drop test. Uiaa's highest standard of impact for the first fall is 985 kg. To hang a weight of 65 kilograms (176 pounds) at one end of a rope to see the length of the rope. When the power rope is under load, it will definitely stretch a little. Uiaa standard is less than 8%. But it is different in the drop. The rope will stretch 20-30% in the uiaa test. When the sliding rope of rope jacket is subject to friction. The jacket will slide along the core. During the test of uiaa, the weight of 45kg is hung by a 2,2m rope and pulled by friction on the edge for 5 times, and the sliding of the outer jacket shall not exceed 4cm.