The history of the use of ropes in mountaineering dates back to the first ascents in the Alps in the 18th century. At first, these were twisted linen ropes, which could withstand a jerk of up to 700 kg and could not provide the required reliability. The complexity of climbing routes gradually increased, production technologies changed, and in the 1950s synthetic ropes began to be used, which led to the emergence of dynamic ropes and new belay methods ( bottom blind belay, see insurance for more details). In the city, Edelrid was the first to use braided rope (rope cable structure; For more information about the structure of ropes, see cable).
Types of ropes
Materials
Climbing ropes are made mainly of polyamide (nylon, nylon - strong, elastic, wear-resistant, quite resistant to moisture and chemicals except acids). Sometimes polyester is also used (less elastic and the rope does not hold the knot well), rarely Kevlar (Kevlar ropes are the strongest, but the least durable and do not hold the knot well).
Twisted and braided ropes
Currently, there are two types of ropes: twisted and braided (cable type ropes). Usually, with the same material and the same thickness, twisted rope, in comparison with braided rope, has better strength and dynamic characteristics. At the same time, due to the fact that a braided rope has a load-bearing core and a protective braid, it is better protected from mechanical damage and the adverse effects of sunlight. A typical rope of this type has a core consisting of several tens of thousands of synthetic threads. They are distributed in two, three or more straight, braided or twisted strands, depending on the specific design and required performance characteristics. For example, the core of the dynamic rope "Classic" manufactured by Edelrid consists of 50,400 threads with a thickness of 0.025 mm, and its protective braid is made of 27,000 threads. Braided ropes are also more convenient for tying knots.
The protective sheathing of climbing ropes is usually painted. The colors can be very different, but they are always bright, which makes it convenient when working with two or more ropes. The sheath of most caving ropes and “technical” ropes is white.
Rope diameter
The diameter of dynamic and static ropes produced by most specialized companies most often ranges from 9 to 11 mm. The diameter of technical ropes used in industrial mountaineering is 10-12 mm. During competitions, the judge's belay can be made with a 12-, 14- and 16-mm rope.
Important: in practical work, the thickness of the rope relates only to the overall weight, flexibility, ease of handling, etc. and is not an indicator of the reliability of the rope (see below).
Dynamic and static ropes
Factor (coefficient) of fall
The fall factor is determined by the ratio of the height of the fall to the length of the rope that holds it.
The maximum possible (and most unfavorable) fall factor is 2, when the fall point is one length of rope higher than the belay point. When falling from the level of the safety point, the fall factor is 1.
Note: Dynamic loads are loads that quickly change in magnitude and direction.
The main distinguishing feature that determines the type of this rope is its dynamic qualities - the ability to lengthen under load. Even when constructing a rope, depending on the desired performance properties, the ability to elongate is set both during normal use and when absorbing a dynamic shock. In accordance with the degree of elongation under load, as well as the purposes for which it is produced, rope is divided into two main types: dynamic, or climbing rope, and static, or caving rope.
Dynamic ropes
The main property of dynamic ropes is the ability to absorb dynamic shock that occurs during a fall with a fall factor greater than 1 (see sidebar). Produced mainly for mountaineering needs. Their main qualities are determined by UIAA standards.
UIAA and EN892 (European requirements) requirements for dynamic rope:
- The jerk force must be no more than 12 kN at a jerk factor of 2 with a weight of 80 kg (55 kg for half rope or double rope);
- The rope must withstand at least 5 jerks with a jerk factor of 2 and the weight specified above;
- The elongation should not be more than 8% under a load of 80 kg (for a half rope no more than 10% under a load of 80 kg);
- Flexibility when tying knots - the flexibility coefficient (diameter of the rope/diameter of the rope inside the knot with a load of 10 kg) should be no more than 1.2;
- Displacement of the rope sheath relative to the core - 2 meters of rope are pulled through a special device 5 times. The displacement of the rope sheath relative to the core should be less than 40 mm;
- The marking must indicate the type of rope (single, half rope or double rope), manufacturer and CE certificate.
The Dodero test is used to test dynamic ropes. The best types of rope can withstand up to 16 pulls.
Flaws
Dynamic ropes are of the following types:
Single dynamic rope or main rope
Single (main) is a type of dynamic rope that, by its design, is intended to be used for belaying during free climbing and has the necessary qualities to reliably arrest a fall with a maximum factor of 2. The thickness of the main rope is most often from 10.5 to 11.5 mm. As it moves, the rope is sequentially snapped into the carabiners of the intermediate belay points.
Advantages
- Single rope is the most durable to use and easier to work with;
- It is lighter than two half ropes (but heavier than a double rope).
Flaws
- Unlike double ropes, it is less protected from being interrupted by stones, ice or from being cut on the sharp edge of a rock;
- It is necessary to ensure that when passing through intermediate points it does not make large bends, since this increases friction during its passage, it is difficult to select the rope, this can lead to a breakdown, and slows down the work of the first one in the bunch;
- When passing through many carabiners during a fall, due to friction, the rope may not lengthen and the dynamic properties may not be fully realized.
To avoid this, it is necessary to use quickdraws, position the safety points more optimally, straightening the course of the rope.
Half rope
A half-rope is a dynamic rope, which must be doubled when belaying. A single half rope does not have the necessary qualities to withstand a factor 2 fall. Half ropes are 8.5-10 mm thick. When using a system of two half-ropes, they are alternately fastened into different carabiners and different belay points, forming two parallel tracks. The half-ropes are snapped into the carabiners alternately, distributing one rope on the right in the direction of travel, the other on the left. Overlapping of ropes is not allowed. Usually half ropes of different colors are used.
Advantages
- Each rope is fastened into a smaller number of carabiners;
- When using two half-ropes, friction in the carabiners and on the terrain is reduced, which helps when working on difficult routes.
- They are more protected from interruption, although each rope is less reliable on its own and fails faster due to damage to the braid;
- Convenient for rappelling (downhill) - no need to carry another rope. One rope is used for descent, the other for belaying.
Flaws
- Belay techniques are more complex than for a single rope and require more experience and attention from the belayer. When using the bottom belay, you must ensure that there is no slack in each of the ropes. When a rope is snapped into the intermediate point carabiner, the first one in the bunch selects one of the ropes. The insurer must promptly issue it and, if necessary, urgently return it to its original position. In this case, the location of the other branch of the rope does not change;
- A pair of two ropes is heavier than a single rope;
- Less durable.
Double rope
Double (double or twisting) rope - used as a single rope, both ropes are snapped simultaneously into each carabiner. The diameter of the double rope is 7.8-9 mm. According to some authors, a double rope needs to be snapped into the belay point through different carabiners, since if the rope breaks, they can pinch each other and break apart.
Advantages
- It is easier to choose it first in a bundle (2 thin ropes pass through carabiners and terrain more easily);
- It is convenient to use when rappelling;
- Lighter than single and double rope.
Flaws
- It is thinner and more easily damaged;
- It cannot be used for railings.
Static ropes
In the second half of the 1960s, two new devices entered the practice of speleology and mountaineering - a descender and a grabber (zhumar). Their rapid and widespread distribution in just a few years completely changed the technique of traversing vertical caves. After the rope became the main means of not only belaying, but also climbing, its great elasticity, useful for belaying, immediately turned into its main disadvantage (see disadvantages of dynamic ropes). All this required the creation of a rope with a low degree of elongation, which was called static. Such a rope is produced primarily for the purposes of speleology, and therefore is also called “speleological”.
As the name suggests, static rope has limited elasticity and is not designed to absorb large dynamic loads. A static rope can withstand a fall with a factor of less than 1.
Features of static rope
- Static rope is used for fixed hanging, that is, for hanging wells and installing railings;
- Due to its lower elongation, its ability to absorb energy is lower and peak dynamic loads are greater. They exceed 1000 kgf when falling a load weighing 80 kg with a factor of only 1, while for a dynamic rope this value is rarely exceeded even when falling with the highest factor of 2.
- The lower the elasticity of the rope, the lower the permissible fall factor;
- A static rope can be used to belay a partner only if the belay is from above.
PrEN 1891 (European requirements) requirements for static ropes:
- The jerk force must be less than 6 kN with a jerk factor of 0.3 and a weight of 100 kg;
- The rope must withstand at least 5 jerks with a fall factor of 1 and a weight of 100 kg, with a figure eight knot;
- The elongation occurring under a load of 50 to 150 kg should not exceed 5%;
- The flexibility coefficient when tying knots (diameter of the rope/diameter of the rope inside the knot with a load of 10 kg) should be no more than 1.2;
- Displacement of the rope braid relative to the core - 2 meters of rope are pulled through a special device 5 times. The displacement of the rope braid relative to the core should be no more than 15 mm;
- The weight of the rope braid should not exceed a certain proportion of the total weight of the rope;
- Static breaking force - the rope must withstand at least 22 kN (for ropes with a diameter of 10 mm or more) or 18 kN (for 9 mm ropes), with a figure-of-eight knot - 15 kN.
- Marking - at the ends of the rope the type of rope (A or B), diameter, and manufacturer are indicated.
There are 2 types of static ropes:
Type A
Type A - used for high-altitude and rescue work, as well as for caving.
Type B
Type B is a rope of smaller diameter and is designed for less load than a type A rope. It can only be used for rappelling.
Static-dynamic rope
In an effort to combine the properties of dynamic and static ropes in one rope, designers from several companies developed a version of it - the so-called static-dynamic rope.
Static-dynamic rope also has a cable structure, but consists of three structural elements: two load-bearing cores that are different in their dynamic qualities and a protective braid. The central core of static-dynamic ropes consists of polyester or Kevlar fibers. It is pre-tensioned to a certain limit to reduce its ability to elongate under load. The second core, braided around the central one, is made of polyamide fibers, which are more elastic than polyester or Kevlar. The protective braiding fibers are also polyamide.
The idea behind this design is this: during normal use, that is, during descent and ascent, the load is taken entirely by the less elastic core, and the behavior of the rope up to a load of 650-700 kg is static. With a load of over 700 kg, this core breaks and at the same time absorbs part of the fall energy. The remaining part of it is absorbed by the much more elastic polyamide core that comes into action.
Miscellaneous
Strength of ropes
The declared tensile strength values guaranteed by manufacturers are very impressive - from 1700 kg for a 9 mm rope to 3500 kg for a 14 mm rope and more. However, many factors reduce the strength of ropes and you should not rely on these numbers:
- Bending in knots - depending on the knot, the strength of the rope weakens by 30-60% (from 30% for a nine knot to 59% for a counter conductor knot). The forces acting on a loaded rope without knots are distributed evenly over its entire cross-section. If the rope bends, the forces under loading are distributed unevenly. Some of the threads located on the outside of the arc are stretched quite strongly. In the bending zone, transverse forces also arise, which are added to the longitudinal ones and additionally load the rope threads. The more it is bent, the more its strength decreases;
- Effect of water and humidity - The absorption of water by the polyamide fibers that make up the rope is significant. Tests with knots have shown that wet rope is 4-7% weaker than dry rope. When a wet rope freezes, its strength decreases even more, to 18-22%. Wet Kevlar ropes are up to 40% weaker;
- Aging - under the influence of photochemical and thermal processes, as well as due to the oxidative effects of air, polymers are subject to a continuous progressive irreversible process - depolymerization or aging. Depolymerization occurs especially quickly in the first months after production, then the process slows down. Aging processes occur regardless of whether the rope is in use or not. The process is especially intense under the influence of heat and light.
- Wear during use - as a result of the mechanical influences to which the rope is exposed during operation, simultaneously with aging, it wears out physically. The abrasive effect due to friction makes a particularly large contribution to the reduction in strength. A descender littered with clay, dirt, etc. has a particularly unfavorable effect, which contributes to intensive wear of the rope. Even with slight contamination by clay, the strength decreases by about 10% in a short time.
All the above facts lead to the fact that practical The strength of a used rope may be significantly less than the declared values. For example, the Edelrid-Superstatic caving rope produced in 1981-82 has a declared strength of 2500 kgf. After 5 years of operation, its practical strength was less than 700 kgf.
Rope mass
The weight of the rope depends on its thickness. Its value is measured under standard conditions (air humidity 65%, temperature 20 °C) and is indicated by the manufacturer in the rope passport (in grams per meter). Typically the weight ranges from 52 to 77 g/m depending on thickness and design. Wet rope is up to 40% heavier than its original mass. Nowadays, impregnated ropes are used for caving, which get less wet (“Drylonglife”, “Everdry”, “Superdry”).
Storage
- The rope should be stored in a dry, dark, cool place, preferably in a case.
- It cannot be kept in a stretched state, as its elastic properties are lost.
- If the rope becomes dirty, it must be washed with a special detergent (or simply rinsed thoroughly in cold water), after which, after rinsing well from the detergent, dry it in an unfolded (not stretched) state.
- Do not expose the rope to chemicals or heat. You need to know that ultraviolet radiation has little effect on the strength of a good rope, but any source of heat spoils and destroys synthetic fibers. Do not dry the rope near heating appliances or under the hot sun.
- Carefully inspect the rope for damage to the braid or internal damage, especially before use. If there is damage, replace the rope or cut off the damaged area.
- After strong jerks, it is advisable to replace the rope (the passport indicates how many jerks the rope is designed for).
- The rope can be used for 2 years, but no more than 5 years from the date of issue. In this case, aging of the fibers and their depolymerization occurs. After 5 years, its properties may change and it will not meet UIAA standards. G. Huber’s book “Mountaineering Today” provides the following criterion for the duration of rope use - use an 11 mm rope for no more than 300 climbing lengths.
Rope length
In mountaineering, there is a unit for measuring the length of a complex slope - a rope. Classically, it is equal to 40 meters, this is a distance of comfortable audibility, and often visibility, of the members of the team, however, this length of ropes has almost completely lost its relevance, giving way to ropes of 50 m each. The latest trends in mountaineering, the development of belay devices, communications equipment, an increase in the complexity of routes , lead to the spread of 60 meter ropes, and the European standard for new routes is 70 meter ropes.
see also
Literature
- Zakharov P. P., Mountaineering instructor, ISBN 5-8134-0045-1
- O. Kondratyev, O. Dobrov, Industrial mountaineering techniques, ISBN 5-8479-0038-4
| Rock climbing and mountaineering | |
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| Classification | Mountaineering · Industrial mountaineering · Rock climbing · Speleotourism · Mountain tourism · Ice climbing · Rappelling |
| Places | Climbing wall · |
The use of ropes and ropes became firmly established in the life of mankind many centuries ago; this is one of the first useful inventions of man. But, despite their age, these products are still actively used today. Ropes and cords have long been successfully used in industry and construction, aviation and automotive manufacturing, shipping and shipbuilding, sports, interior design, as well as for household needs. New materials (polypropylene, Kevlar, etc.) create an even greater variety of ropes and ropes, which is directly related to the breadth of their applications.
But first of all, let's understand the terminology:
Rope- a flexible and thin product made of natural or synthetic fibers (strands), twisted or twisted, intended for household needs.
It should be noted that the names of ropes, cords and cords for various areas and applications are practically the same functionally. For example, a cable for towing cars can be successfully used as a rope for tying loads.
Rope- a strong and thick rope made of intertwined plant, synthetic or metal fibers.
Cord- a fairly thin rope, wire or twine.
Twine twine- a thin, strong thread made from bast, chemical fibers or threads, as well as their combinations, or by twisting paper. Used for packaging, stitching, etc.
Cable- a rope product of twisted or twisted shape.
When choosing a rope or rope, we take into account the main characteristics.
- Specific gravity (density)
- Strength, stretchability
- Thickness
- Resistance to abrasion (mechanical damage due to friction)
- Temperature resistance
- UV resistance
- Moisture absorption
The materials from which ropes and ropes are made mainly determine their characteristics, physical and chemical properties and, accordingly, their scope.
The main materials for making ropes and ropes are divided into 2 main classes: vegetable and synthetic.
Vegetable: sisal, hemp, coconut fiber, cotton, jute, flax, etc.
Synthetic: polypropylene, polyamide, polyester, polyethylene, polyester, polypropene, Kevlar.
Let's briefly consider the main ones:
Polypropylene- elastic and non-hygroscopic material with a density of 0.91 g/cm 3, having good electrical insulating properties and increased buoyancy. Resistant to alkalis, acids, and organic solvents and does not lose strength when wet. Polypropylene has low thermal stability and melts at t 165 0 C.
Polyamide- high-strength, flexible and elastic material with a density of 1.14 g/cm 3, which has good resistance to abrasion, jerking and impact loads. It has average insulating properties, is resistant to alkalis and rotting. It exhibits its properties well at temperatures from -40 to +60. At the same time, polyamide is unstable to the action of concentrated acids and organic solvents, changes properties in a humid environment and absorbs moisture, becomes electrified, and also has low resistance to thermal and solar radiation. Melts at t 215 0 C.
Jute or jute twine- a natural, environmentally friendly fiber that has good resistance to mechanical stress and UV radiation and does not accumulate static electricity. Has a lower breaking load than hemp ropes. Jute fiber is susceptible to rotting, as well as acids and alkalis, and does not emit toxic substances when burned.
Cotton- natural fiber with a density of 1.50 g/cm 3, which has moderate hygroscopicity and excellent mechanical properties. Cotton ropes are light, soft and elastic, they are distinguished by thermal stability and good dielectric properties. The strength of cotton ropes when wet increases by 10-15%. At the same time, cotton has average resistance to sunlight, is destroyed by exposure to alkalis and acids, and is susceptible to rotting. Cotton also has low abrasion resistance.
The most important characteristics of rope products are reflected in their labeling(using the example of a product presented in Promsnab):
"Rope" PA Rope polyamide 5.0mm-set. ~60m/kg, 490kgs
"Rope"- name of the factory
PA- material (polyamide)
Rope polyamide- Name,
5.0 mm- diameter of the rope,
set. - can be used for fishing nets,
~60 m/kg- meters per 1 kg - approximate density of the product,
Application of ropes, ropes, cord
- For the household and everyday life - household and washing ropes and cables, ropes for tying various things, cables for towing cars and various vehicles, in tourism for stretching awnings and tents, creating fencing, establishing a crossing, in mountaineering, ropes for horizontal bars and swings, etc. d.
- In agricultural activities - cords for tying cucumbers in greenhouses, for tying vegetables, for tightening transported stacks of hay or straw, etc.
- In yachting - yacht sheets, halyards, mooring lines; as running and standing rigging.
- In production - ropes and cords for packaging products, for tightening furniture, for installing various types of fences, as submersible and load-bearing ropes for nets, cargo ropes for loading and unloading operations, lifting and moving cargo, in shipping for towing barges and ships etc..
- In interior design - for decorating and decorating premises, creating furniture.
For all the above applications you will find in Promsnab. Our product line includes: ropes, cord, twine, keeper tape, polypropylene ropes, polyamide ropes, jute ropes, cotton ropes, etc. The main range of Promsnab rope and rope products is produced at the “Rope” factory, which has more than two centuries of experience manufacturing high quality products.
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Like the article on the topic of equipment certification, published in the first issue of the Mountains magazine, this text does not pretend to be scientific or comprehensive. This is more of an educational program, a brief overview. Conventionally, ropes can be divided into three groups: dynamic, static and special. We will not analyze the latter at all, since their use lies outside our usual activities in the mountains. I will give just two examples: ropes with aramid (Kevlar) braid and ropes with metal mesh inside. Rope with aramid braid has increased resistance to high temperatures and relatively low static elongation; The metal mesh between the braid and the core gives the rope anti-vandal properties. Structurally, all ropes consist of two components: a core, which bears the main load and consists of threads and braiding, the main function of which is to protect the core and give the rope its usual round appearance. Depending on the number of threads in the braid, it can be 48, 32 or 40 strands. The most common versions are 48 and 32. 32-strand braid is more durable due to the thicker braid, but is rougher to the touch and slightly stiffer than 48-strand. Typically, the braid and core are not connected to each other in any way, so a shear shear effect occurs. This is especially evident if the rope is often used for descents. This also manifests itself when cutting the braid of a loaded rope with a sharp edge or biting it with a jumar - the braid slips. There are technologies for “gluing” the braid to the core. This increases the safety of the rope: even if you slash the braiding with a knife, it does not slip. Of course, the price of such ropes is much higher. |
Static ropes
Static ropes have high strength and a relatively low static elongation of 3–5%. Such ropes are used for organizing railings in the mountains, for rescue work, industrial mountaineering, speleology, canyoning, arboriculture, etc., but they are not intended for belaying. More precisely, they should not be used when a fall with a jerk factor of 1 or more is potentially possible. Any options for lower insurance are excluded, while upper insurance is questionable. Most manufacturers indicate in their instructions that it is not permissible to use a static rope as a safety net. The exception is when carrying out rescue operations.
You can often see lanyard “whiskers” made from static rope. If the lanyard is not used correctly, the probability of a fall with a jerk factor greater than 1 is very high, so it is better not to use lanyards made of static rope.
Characteristics of static ropes
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Rope type(A or B). The main difference is the minimum static strength. According to the standard, type A ropes must have a minimum static strength of 22 kN, type B - 18 kN. Typically, type B ropes are 9mm in diameter.
Relative extension(Elongation). The degree of elongation of a rope under load. The test is carried out under a load of 150 kg. The value should not exceed 5%. This is usually around 3%.
Braid shift(Sheath slippage). This parameter is very important if the rope is used for descents. With a large shift of the braid, a situation is possible where at the end of the run the braid is still there, but the core has long since run out. The braid shear test is quite difficult to describe. The ideal value is 0 mm, the maximum is 20 mm per 2 meters of rope (1%). More often this value is 0–5 mm.
Shrinkage(Shrinkage). A characteristic that is worth dwelling on in more detail. The vast majority of ropes produced in the world undergo a heat-setting process: after weaving, the rope
is moistened with a special composition and placed in a cabinet with a temperature of about 150 degrees. As a result of this action, the rope shrinks at the factory. A good shrinkage value is 1.5–2%. Those. a rope 50 meters long will “sit” about a meter after some time. But! All this does not apply to ropes produced in our country, as well as to ropes made in Belarus and Ukraine. They do not undergo a heat setting process and their shrinkage is up to 15%. In order to have a rope 50 meters long, you need to buy 55, or better yet 60 meters. It should be noted that this parameter is not regulated by either the domestic standard GOST-R EN1891-2012 (entered into force on January 1, 2013) or the European standard EN1891 due to the fact that this parameter does not directly affect the performance properties of the rope. So it’s formally impossible to blame individual manufacturers for the lack of heat setting, but sometimes you really want to.
Static strength(Static strength). The minimum is 22 kN for type A and 18 kN for type B. For ropes with a diameter of 10 millimeters or more, it is close to 30 kN (three tons). There is also a parameter - “Strength with knots”. This is approximately 70% of the static strength, although it all depends on the knot. Some manufacturers indicate that the actual working load on the rope should not exceed 10% of the static strength. Those. if the rope has a static strength of, for example, 32 kN, then this means that the working load should not exceed 3.2 kN (320 kg).
Knotting coefficient(Knotability). This parameter characterizes the softness of the rope. A simple knot is tied on the rope and a 10 kg load is suspended for one minute. Then the load is reduced to 1 kg and measurements are taken. The ratio of the internal diameter of the knot to the diameter of the rope is the knotting coefficient. The internal diameter of the assembly is measured with a measuring cone. A value of 0.6-0.7 indicates the tactile softness of the rope, 1.0 and higher indicates a high rigidity of the rope. There are examples of domestic rope with a value of 2 or even more. This characteristic of a static rope is not always indicated by manufacturers. Number of falls: static ropes undergo dynamic tests that determine this indicator. A load of 100 kg for Type A ropes or 80 kg for Type B ropes is released with a jerk factor of 1. The rope must withstand at least five jerks. Typically this value is several times higher.
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Dynamic ropes
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The main and, in fact, the only purpose of dynamic ropes is insurance. Top, bottom - any. The exception is insurance during rescue operations, where it is better to avoid dynamic ropes if possible. The advent of dynamic ropes led to the disappearance of such a technique as “rope etching”. When all the ropes were static, pickling was necessary in order to minimize the load on the top point and on the person who fell through a smooth application of the load, i.e., stretching the load over time. Each climbing camp had a safety stand, where this technique was carefully practiced. This was vital.
The property of a dynamic rope is to absorb shock energy by lengthening the rope. In fact, this is the same etching only automatic. In this case, additional etching is not only not required, but also dangerous: when falling with an exit above the bottom point, the person flies 2 distances above the point plus dynamic elongation of the rope (about 35%). Those. the depth of fall below the top point is about three times the length of the excess above the point. The rope can reduce the load on the top point and on the person who has fallen to relatively safe values, but the danger of hitting the terrain remains. If you additionally etch the rope, this will only increase the depth of the fall and, therefore, increase the risk of hitting the terrain.
In one of the alpine camps, I regularly observe groups of beginners, whom different instructors bring to an old, but still living belay stand and demonstrate to them “jerk strength.” This all happens using an old static rope as a safety net. The beginner firmly clamps the rope in the belay device and, when jerking, flies up to the length of his lanyard. The instructor says: “Look, you see what a jerk!” At the same time, he does not even understand that he is grossly violating safety regulations by using a static rope as a safety net. The jerk factor in such tests is clearly higher than 1. Such a demonstration is not only unsafe, but also meaningless, since a jerk of such force will never occur if a dynamic rope is used. Namely, it should be used, and the mountaineering instructor cannot but know about it.
All that has been said about pickling does not mean that it is always dangerous. For example, when working in the snow, it can be life-saving. Apparently, you can come up with a situation on the rocks. But! The Italian alpine club conducted a study on the timing of peak load. It turned out that if during a fall with a lower belay, the maximum force on the person who has fallen occurs 0.2 seconds after the fall, then on the belayer only after 0.8 seconds. Those. when the second one felt a tug, the leader had already “gotten it”...
Types of dynamic ropes
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Depending on the purpose of use, there are three types of ropes:
Single(single) - a regular rope that can be used for belaying. Such a rope is marked with the number 1 in a circle. Single rope diameter from 8.7 mm.
Double(half) - a rope with a diameter of 7.5 mm or more, which is used in pairs with another similar rope, and they are alternately fastened to different intermediate belay points. Such ropes are marked with the 1/2 symbol.
Twin(twin) - the rope also has a diameter of 7.5 mm. The use of double ropes implies their use as one, i.e. both ropes are fastened together at all intermediate belay points. Such ropes are marked with a symbol consisting of two intersecting rings. It should be noted that the vast majority of ropes with a diameter of 7.5–8.5 mm will satisfy both the double and twin standards. It is unacceptable to use half and twin ropes as single ropes.
Water-repellent impregnation of dynamic ropes
As long as the rope is new and dry, it does not matter whether it is soaked or not. Ropes that are used indoors do not need impregnation. But as soon as contact with water occurs, the situation changes. There are three main problems:
- The strength of a wet rope is more than half that of a dry one. When testing for the number of pulls, a wet rope can withstand one or two, maximum three pulls. After drying, the properties are restored.
- Glacial water often carries with it a suspension that penetrates with the water into the rope and then remains there. When dried, it turns into an abrasive, which leads to rapid wear of the rope.
- The most obvious thing is that wet rope weighs much more than dry rope. It is difficult to carry, uncomfortable and unpleasant to work with. Everyone is familiar with the situation when, when descending a wet rope, a stream of water is poured onto your hands, squeezed out by the braking device. And if the temperature drops below zero, the wet rope turns into wire.
Conclusion: we must fight water.
High-quality, and most importantly durable water-repellent impregnation is a headache for manufacturers. There are three types of rope on the market: without impregnation, with impregnation of the braid, and with full impregnation (braid and core). The price of a rope with impregnation is certainly higher than without it.
At a meeting of the UIAA Safety Commission in 2012, an interesting study was presented, from which it follows that impregnation of only the braid is extremely short-lived and very quickly the properties of such a rope become similar to the properties of a rope without impregnation. Therefore, when choosing a rope with impregnation, you do not need to save money by buying a “semi-impregnated” product. You are simply overpaying or expecting a very short lifespan for this rope.
But you need to understand that the life of the impregnation is in any case shorter than the life of the rope. What to choose? For use at a climbing wall, rock climbing, climbing on dry rocks or in known frost, a rope with impregnation is not needed. Although it should be noted that the presence of impregnation gives the rope greater wear resistance even in dry operating conditions. If we are talking about “all-weather”, “ordinary” mountain conditions, then impregnated ropes are preferable.
Main characteristics of dynamic ropes
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I would like to note right away that for dynamic ropes the concept of “static strength” is practically not used. It is almost the same as for static ropes of the same diameter, but this parameter is not so important for a dynamic rope.
First pull force(Impact force). The most important characteristic for a dynamic rope. This is the maximum force that occurs in the safety chain during a fall with a jerk factor equal to approximately 1.77 of an 80 kg load (55 kg for half ropes and 80 kg for two twin ropes). According to the standard, this force should not exceed 12 kN (1200 kg). Real values are 7.5–10 kN. This largely depends on the manufacturer. Some people produce ropes with a low first pull force, but this results in a higher relative elongation. Others, on the contrary, try to make ropes with a relatively “hard” jerk, but at the same time the relative elongation decreases.
Number of jerks UIAA(Number of falls UIAA). A piece of rope is rigidly fixed at one end. A load weighing 80 kg (55 kg for the half type) is attached to the other end and dropped down with a factor of 1.77. In this case, the rope hits the carbine (rod with R=5 mm). The test is repeated at intervals of 5 minutes (during this time the rope “rests”) until the first damage to the rope. According to the standard, there should be at least 5 such jerks. Usually this value is 7–10 and higher. It should be noted that the test is carried out using a carbine (rod) with a radius of 5 mm, and modern carabiners used in quickdraws usually have a smaller radius. Obviously, the number of jerks will be less.
Static elongation(Static elongation). This parameter becomes important if the rope is used as a handrail. You can often hear the phrase: “jumbling along a dynamic rope?!” What are you talking about! As a rule, this is said by those who use the products of one of the two factories that produce dynamic rope in our country. These ropes are produced using very outdated technologies and they really are “elastic bands”. According to the standard, this parameter should not exceed 10%, but usually it is 7–8%, which, of course, is not very good for a fixed rope, but if you look at it, it is only twice as high as static ropes. Of course, it is better to use “static” for railings, but using modern “dynamic” is not as inconvenient as it was 10–15 years ago.
Dynamic elongation(dynamic elongation).
This is actually what dampens the jerk - “etching”. According to the standard, the maximum value is 40%. Realistically 30–35%. Typically, the lower the force of the first pull, the greater the extension - and vice versa.
We considered sheath shift and knotting coefficient when talking about static ropes (it is not defined according to the EN892 standard, but it is usually calculated).
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Concluding the conversation about dynamic ropes, I would like to note that some Russian manufacturers, for unknown reasons, mislead buyers by calling obviously static ropes dynamic. The falsity of this statement can be easily verified by opening the passport attached to the rope with the requirements of the standards. If for some reason nothing comes with the rope (which often happens), then is it worth buying this rope at all?
You can buy different types of rope from the Cord Factory - a manufacturer of ropes, ropes, cords, halyards (polyamide, nylon, twisted). WE work all over Russia. Buy ropes and ropes wholesale.
Climbing rope- a special rope with special dynamic and strength properties.
Clothesline- this is the most popular product that our company produces. It consists of polypropylene thread. Very durable and easy to use. Used on the farm. You can buy a clothesline from us!
Bay- a roll of something long, such as wire or rope.
Rope- the most general name for a thick thread twisted or lowered into several strands, usually hemp; Each strand is first twisted on its own, from the heel, and then three, sometimes four strands are pulled down together.
Twisted ropes- products similar in design to ropes, but of smaller diameter. They are used in cases where the requirements for strength and wear resistance are reduced.
Fiber- a class of materials consisting of unspun strands of material or long thin pieces of thread. Fiber is used in nature by both animals and plants to hold tissues (biological). The fiber is used by humans to spin threads, ropes, as part of composite materials, and also to produce materials such as paper or felt.
Man-made fibers:
- hydrated cellulose;
- viscose, lyocell;
- copper-ammonia;
- cellulose acetate;
- acetate;
- triacetate;
- protein;
- casein;
- zein
Synthetic fibers(trade names are given in brackets):
- carbon chain
- polyacrylonitrile (nitron, orlon, acrylan, cashmilon, curtel, dralon, volprula);
- polyvinyl chloride (chlorin, saran, vinon, roville, teviron);
- polyvinyl alcohol (vinol, mtilan, vinylon, kuralon, vinalon);
- polyethylene (spectra, dyneema, tekmilon);
- polypropylene (Herculon, Ulstrene, found, meraklon);
- heterochain;
- polyester (lavsan, terylene, dacron, tetheron, elana, tergal, tesil);
- polyamide (nylon, nylon-6, perlon, dederon, amylan, anide, nylon-6,6, rhodium-nylon, nylon, nomex);
- polyurethane (spandex, lycra, virin, espa, neolan, spanzel, vorin).
Flexibility- product compliance to bending influences. This characteristic, the inverse of bending rigidity, depends on the properties of the source material of the product, its design and formation parameters.
Wear resistance- the ability to resist deterioration or gradual destruction of the material under the influence of external friction. All other things being equal, it is believed that the higher the strength, the higher the wear resistance.
Heeled- an element of a twisted (woven) product, twisted from several chemical threads, or yarn from natural or chemical fibers.
Twisted products- the range of twisted products is very diverse - from thin sewing threads to thick and durable marine ropes. Twisted products sometimes include semi-finished products in the form of twisted threads (twisted yarn), fancy yarn, etc., used in weaving, knitting, and other industries. Twisted products are produced: cotton (sewing and embroidery threads, cord, netting, drive ropes); from bast fibers (threads, cords, twine, ropes, trawls and ropes); from natural silk (sewing threads and surgical silk, cords); from wool (yarn for knitting). Twisted products made from chemical fibers are becoming increasingly widespread, the use of which increases production efficiency and significantly improves the properties of products. During production, several threads folded together are usually twisted with different numbers of twists. Spun products are often subjected to bleaching, dyeing, etc.
Rope- a synonym for “cable”, previously in maritime affairs - a hemp cable more than 13 inches in circumference, or a cable of equal strength made of other materials, regardless of size.. The word is also used in relation to a thicker cable compared to thin ropes. Currently there is no clear boundary.
Rope- the thickest rope; to the south there is a rope in general, a monster; Morsk. sheyma, a thick rope (cable work) on which the dead anchor is thrown; the wereps are thrown on the perlines. Weight dancers walk on a tightrope. The ferry walks on a tightrope.
Capron- synthetic polyamide fiber obtained from caprolactam a. Ropes, fishing nets, etc. are made from nylon.
Linear density (mass per unit length)- an indirect characteristic of the thickness of a twisted (wicker) product, measured in tex. The mass of a twisted (wicker) product with normalized humidity. It is determined according to GOST 10681-75 and is used when handing over and accepting products. The normalized humidity for products made of nylon is 5%, for cotton - 7-8.5%, for hemp and flax - 12-14%, for polypropylene - not standardized.
Nonwovens- textile products made from fibers or threads joined together without the use of weaving methods.
Thread- the general name for a thinly twisted material having a small diameter. Threads are produced on packages: spools, hard paper sleeves, skeins, bobbins, and bundles. As a material, threads can be natural (from combed yarn) or synthetic (synthetic material, including fiberglass, is used as a base). Depending on the type and brand, threads can be: harsh, matte and glossy. Matte threads produced with a special fat coating are called “shoe threads”.
Braiding cords- the weaving of cords can be different. We offer cords with core and cords without core.
Polypropylene thread- This is an environmentally friendly material, which allows the use of products made from it in contact with food. Unlike many other types of polymer threads, polypropylene thread is not electrified. The technology assumes the possibility of producing two types of thread: fibrillated and multifilament. Fibrillated polypropylene thread is made on the basis of polymer films, which are cut from the base material into strips, and then they are oriented or fibrillated. Polypropylene multifilament The thread is formed from polypropylene, which ensures their greater strength. The use of polypropylene threads is possible in a wide variety of areas, although so far the development of polypropylene thread production in our country is not progressing at a fast enough pace. Meanwhile, the latest technologies for processing polypropylene make it possible to obtain polypropylene thread with high consumer qualities. This material can be used for the manufacture of belts for various purposes, from haberdashery to conveyor belts, ropes, cords, cables, fishing nets, threads for sewing bags, etc.
Weaving- one of the methods of processing such materials as bast, leather, hemp, straw and other similar soft raw materials available from the craft in the form of strips for the production of coarse fabric-like sheets that can be used for the manufacture of products such as baskets, hats, bast shoes, matting, mats, rugs, etc. In jewelry, macrame elements made from “cylindrical” leather are often used. lace. In combination with perforation, leather weaving is used to braid the edges of products (used for finishing clothes, shoes, bags).
Creep- the ability of the product to collapse under prolonged continuous exposure to tensile force. The creep of a product depends mainly on the material, although it has been noted that for products of large diameters creep occurs at a slower rate.
Polyester fiber- a synthetic fiber formed from a melt of polyethylene terephthalate or its derivatives. Advantages: low creasing, excellent light and weather resistance, high strength, good resistance to abrasion and organic solvents; Disadvantages - difficulty of dyeing, strong electrification, rigidity - are eliminated by chemical modification. It is used, for example, in the production of various fabrics, artificial fur, ropes, and for reinforcing tires. Main trade names: lavsan, terylene, dacron, tetheron, elana, tergal, tesil.
Depending on the type, the following polyester fibers are distinguished:
- staple (fibers of final staple length, usually no more than 40-45 mm (cotton staple fibers), used in the textile industry for the production of yarn;
- filament (aka: complex threads, continuous fibers) - are threads formed from individual endless polyester threads of low linear density (tenths of tex and below): characterized by linear density (usually tex - weight in grams of one kilometer of thread ), filamentarity - the number of elementary filaments of which it consists, titer - the average linear density of one filament;
- textured - usually filament fibers subjected to special filament crimping to: add volume - or - connect (compact) filaments together, etc.;
- monofilament;
- bulk threads (BCF). Currently in the global textile industry.
Natural fibers- these are fibers formed biologically (in the body of a plant, animal) or during geological processes.
Strength- the property of resisting destruction from a single applied force. It is assessed mainly by breaking load - the minimum force that destroys the product. It is measured in kilograms of force (kgf) and kilonewtons (kN). 1 kgf = 9.8 N.
Tex- a unit of measurement showing the mass of 1 km of twisted (wicker) product in grams.
Cable- twisted or twisted rope product.
CORD lace and string, string, German. thin twine, thread, cord, silk, gold, etc., twisted and woven. Cords with tassels for curtains. A cord in an account book, threaded through all the sheets of braids, sealed at the ends so that the sheets cannot be changed. Carpenters have a string with which they use chalk or charcoal to mark a line; also the very end, the line that is amused. Follow the cord, don't cross the cord. Masons have a string that is pulled along the wall for straight laying.
Nylon cord- This is a round braided cord made of nylon thread. It is used for insertion into drawstrings, for lacing on many products and for adjusting the width on individual parts of the product. It also performs a decorative function.
Twine (string)- a thin, strong thread for packaging, stitching, etc., made by twisting paper, bast fibers, chemical fibers or threads, as well as their combinations.
To make twine from bast fibers, the following are used: hemp, short flax fiber, kenaf, jute or mixtures of these fibers.
The following chemical threads are used: polypropylene, nylon and viscose threads. Paper twine is made by twisting one, two or three strips of kraft paper. The structure of twine can be single-strand or multi-strand. Multi-strand twine is made by twisting several threads or yarns in the direction opposite to the direction of twist of the original thread or yarn. When making twine from polypropylene threads, it is allowed not to twist the original thread.
Nylon halyard- This is a braided halyard cord, reusable. Designed for serious work, withstands heavy loads. It is characterized as a highly durable and wear-resistant product. Used in construction and industry. These are mainly cargo operations, aviation applications, equipment for ships and for use in outdoor activities. It is also used as towing ropes.
Fibrillation- destruction of bonds between individual fibrils of the walls of plant fibers, which occurs when water penetrates into the interfibrillar space, as well as under the influence of mechanical influences on the cell walls of plant fibers.
Cotton- fiber of plant origin, obtained from cotton bolls - plants of the genus Gossypium.
When the fruit ripens, the cotton boll opens. The fiber along with the seeds—raw cotton—is collected at cotton receiving points, from where it is sent to a cotton gin plant, where the fibers are separated from the seeds. Then follows the separation of the fibers by length: the longest fibers from 20-25 mm are cotton fiber, and the shorter hairs - lint - are used to make cotton wool, as well as for the production of explosives
The main distinguishing feature that determines the type of rope is its dynamic qualities - the ability to lengthen under load. Even when constructing a rope, depending on the desired performance properties, the ability to elongate is set both during normal use and when absorbing a dynamic shock. In accordance with the degree of elongation under load, as well as the purposes for which it is produced, rope is divided into several types:
The diameter of dynamic and static ropes most often ranges from 9 to 11 mm. Ropes with a diameter below 8 mm are called cords and are used as auxiliary ropes. In practical work, the thickness of the rope relates only to the overall weight, flexibility, ease of handling and is not an indicator of the reliability of the rope.
Structurally, all ropes consist of two components: a core, which bears the main load and consists of threads and braid, the main function of which is to protect the core and give the rope its usual round appearance. Depending on the number of threads in the braid, it can be 48, 32 or 40 strands. The most common versions are 48 and 32. 32-strand braid is more durable due to the thicker braid, but is rougher to the touch and slightly stiffer than 48-strand.
As a rule, the braid and the core are not connected to each other in any way, so the effect of shearing of the braid occurs. This is especially evident if the rope is often used for descents. This also manifests itself when cutting the braid of a loaded rope with a sharp edge or biting it with a jumar - the braid slips. There are technologies for “gluing” the braid to the core. This increases the safety of the rope: even if you slash the braiding with a knife, it does not slip. Of course, the price of such ropes is much higher.
Static rope
Low stretch ropes are usually referred to as static ropes. They are used for work at heights, for rescue work, in caving, etc. It is important that a static rope has minimal stretch and maximum strength. After the rope became the main means of not only belaying, but also climbing, its great elasticity, useful for belaying, immediately turned into its main drawback. All this required the creation of a rope with a low degree of elongation, which was called static.
As the name suggests, static rope has limited elasticity and is not designed to absorb large dynamic loads. A static rope can withstand a fall with a jerk factor of less than 1. This means that anyone working on a static rope is strictly prohibited from going above the rope's anchorage point! Static ropes are of type A or B. The main difference is the minimum static strength. Type A ropes according to the standard must have a minimum static strength of 22 kN. Type B 18 kN, usually a rope of smaller diameter and designed for less load.
Main characteristics:
- rope type A or B;
- diameter 9-11 mm;
- number of strands 32, 40, 48;
- static strength.
Advantages:
- Jumars hold well on static ropes;
- Can be used for constant static loads.
Flaws:
- Can withstand falls with a dash factor of only less than 1;
- Has limited elasticity.
Dynamic rope
Dynamic rope – designed for insurance in case of falls. Its task is to ensure minimal load on a person even with a deep breakdown due to elongation. The main property of dynamic ropes is the ability to absorb the dynamic shock that occurs during a fall with a fall factor greater than 1. With each fall, the rope deteriorates. Dynamic ropes are of the following types: 
Single dynamic rope or main rope is a type of dynamic rope, which by its design is intended to be used for belaying during free climbing and has the necessary qualities for reliable fall arrest with a maximum factor of 2. The thickness of the main rope is most often from 10.5 to 11.5 mm . Single rope is the most durable to use and easier to work with. It is lighter than two half ropes (but heavier than a double rope).
A half-rope is a dynamic rope that must be doubled when belaying. A single half rope does not have the necessary qualities to withstand a factor 2 fall. Half ropes are 8.5-10 mm thick. When using a system of two half-ropes, they are alternately fastened into different carabiners and different belay points, forming two parallel tracks. Half rope is less durable.
Double (double or twisting) rope - used as a single rope, both ropes are snapped simultaneously into each carabiner. The diameter of the double rope is 7.8-9 mm. It is convenient to use when rappelling. Lighter than single and double rope. It is thinner and more easily damaged. It cannot be used for railings.
Main characteristics:
- type of rope;
- diameter 9-11 mm;
- number of strands 32, 40, 48;
- weight - the larger the diameter, the greater the weight;
- number of jerks;
- maximum jerk force (for example, 8 kN = 800 kg is what affects a person; the rope will absorb everything above it).
Advantages:
- Withstands falls with factor 2;
- Convenient to use when rappelling;
Flaws:
- on soft ropes the jumars do not hold well, when starting to climb on the jumars you need to mark time until you climb up to 5-6 meters;
- dynamic ropes cannot be used under constant static loads.
Rep cord
Cords are used only for auxiliary purposes (Prussian loops, etc.). The cord should not be used as a rappel rope or belay rope.
Main characteristics:
- diameter 4-8 mm;
- weight - the larger the diameter, the greater the weight;
- tensile strength (breaking load, kgf);
Strength of ropes.
Manufacturers indicate a very impressive tensile strength value.
However, many factors reduce the strength of ropes:
- Influence of water and humidity - The absorption of water by the polyamide fibers that make up the rope is significant. Tests with knots have shown that wet rope is 4-7% weaker than dry rope. When a wet rope freezes, its strength decreases even more, to 18-22%. Wet Kevlar ropes are up to 40% weaker.
- Aging - under the influence of photochemical and thermal processes, as well as due to the oxidative effects of air, polymers are subject to a continuous progressive irreversible process - depolymerization or aging. Depolymerization occurs especially quickly in the first months after production, then the process slows down. Aging processes occur regardless of whether the rope is in use or not. The process is especially intense under the influence of heat and light.
- Wear during use - as a result of the mechanical influences to which the rope is subjected during operation, simultaneously with aging, it wears out physically. The abrasive effect due to friction makes a particularly large contribution to the reduction in strength. A descender littered with clay, dirt, etc. has a particularly unfavorable effect, which contributes to intensive wear of the rope. Even with slight contamination by clay, the strength decreases by about 10% over a short period of time.
- Any knot weakens the rope. Bending in knots - depending on the knot, weakens the strength of the rope by 30-60%. The forces acting on a loaded rope without knots are distributed evenly over its entire cross-section. If the rope bends, the forces under loading are distributed unevenly. Some of the threads located on the outside of the arc are stretched quite strongly. In the bending zone, transverse forces also arise, which are added to the longitudinal ones and additionally load the rope threads. The more it is bent, the more its strength decreases.