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This question sounds simple. But it is not, because the answer must point to limiting factors.
People’s lives are hanging on the climbing rope. Irrespective of their body weight, parameters such as rope thickness, rope age, wear and tear, number of falls caught and improper use determine how much weight a climbing rope holds.
A damaged and worn out climbing rope can never keep its promise to keep 80 kilograms (176 pounds).
Your Survival Depends on the Climbing Rope
Damaged ropes do not necessarily belong in the trash. They can still unfold their usefulness elsewhere. However, they can no longer safely absorb the falling weight of a climber.
The question of the weight that a climbing rope can hold is asked more frequently in forums. There are no general answers. One factor, for example, is a vulnerability that often becomes relevant: The climbing rope hangs in a safety hook.
Once this loosens, it doesn’t matter how much weight the rope would have held or hopefully will hold. At first, the weak point lies somewhere else. If the climbing rope’s broken, it looks bad. Theoretically, the used rope can hold 10 kN weight. That would be 1,000 kilograms (2205 pounds), depending on the rope thickness.
Much more important than this size, however, is the so-called fall factor. This factor can be calculated. Determining parameters are the height from which the camber occurs and the length of rope that was output. The formula is:
fall factor = fall height divided by rope length
For falls from low heights, the fall factor is usually 0.5. However, it can increase considerably if the climbed height is higher and the maximum rope length is given. Modern climbing ropes are many times more durable than the hemp ropes used in the past. Nevertheless, everything depends on proper use, care and storage. Ropes that have already caught several falls hold less weight than climbing ropes that have been newly purchased.
Related article: How to Care for your Climbing Rope
What Weight Must a Climbing Rope be Able to Support?
According to standard EN 892, single ropes must be able to withstand at least five falls, weighing 80 kilograms (176 pounds) and with a fall factor of 1.75. The weight of the falls is 80 kilograms (176 pounds). But only in the first fall does the impact force amount to 12 kN. It is lower for all subsequent ones.
Twin ropes are based on a fall weight of 80 kilograms (176 pounds) but 12 standard falls.
In the test, half ropes and double ropes only have to withstand a drop weight of 55 kilograms (121 pounds) and remain stable for five standard falls. Semi-static climbing ropes (static ropes) absorb falls due to their lack of elasticity – but not without damage.
Related Article: How to Tell if a Rope is Static or Dynamic? Guide + Images
So far, so good. But what is a fall weight compared to body weight? And what’s a norm fall?
The weight factor becomes relevant when you are climbing in a rope team. If your partner is the one who protects you and weighs considerably more than you, then the forces change. It is perceived as harder by you as the falling one.
Even a bodyweight 10 kilograms (22 pounds) heavier when securing should result in additional securing measures for you as a climber. Your body weight unfolds a considerable dynamic during a fall. This increases the body weight to the so-called drop weight. This weight specification is to be set many times higher than what you actually bring to the scales in body weight.
If you weigh 70 kilograms (154 pounds) and fall only two meters deep, the climbing rope has to withstand an impact force of 140 kilograms (309 pounds).
But at a depth of six meters, it’s already 420 kilograms (926 pounds). No human could absorb such weight loads.
With a body weight of 80 kilograms (176 pounds), a fall weight of 350 kilograms (772 pounds) is produced. This puts into perspective the question of the weight that a climbing rope can hold.
Norm Falls and Test Conditions are Unrealistic
Norm falls form a mathematical basis for the dimensioning of the tensile strength of climbing ropes. The basis is a new (!) climbing rope. As a minimum, this must be able to withstand the specified number of standard falls.
Standard crashes, however, are not very practical because they are carried out under test conditions. However, a high number of standard falls means a greater safety reserve. This qualifies a climbing rope as a “multifall rope”.
This is the case when 12 standard falls are indicated. However, this “qualification” or marking merely means that a new climbing rope (!) can withstand several lighter falls. With an old but unused climbing rope, you can no longer accept this factor – and even less so with an already damaged one.
But if you crash hard, you shouldn’t assume that you could afford it eleven more times with the same climbing rope. As a safety-conscious climber, you will take a new climbing rope on your next climbing trip!
Related Article: How to Choose a Rock Climbing Rope
Of course, it could be that your rope can withstand further crashes. But since you never know how many, you better play it safe. A misjudgment can lead to serious injuries and in the worst case to the loss of your life.
Regardless of how much weight your climbing rope can hold, negligence or carelessness is a much more important factor when it comes to accident risks. If you only rely on the carrying capacity of your climbing rope and strain its load capacity through too much routine or careless handling, it won’t pay off.
Apart from that, some fall situations cannot be sufficiently simulated under test conditions. For example, tests for sharp edge strength fail due to the specified test conditions.
If, for example, a sharp rock ridge acts obliquely on the climbing rope during a fall, it will probably tear regardless of your body weight – especially if it has already caught one or more falls or has been damaged due to improper storage.
Even the most beautiful stretched fall won’t help. As a basic rule, if a climbing rope has already caught a violent fall, it should be replaced to be on the safe side.
A climbing rope can withstand several light falls – but only up to the specified standard fall number, and only if it is properly stored and cared for. You should also check your ropes for damage before every climbing trip.
What are the Important Parameters in Standard Testing?
Standard tests are carried out by the climbing rope manufacturers under specified fall conditions.
Such conditions, however, do not occur in reality. This alone complicates the question of what weight a certain climbing rope can hold. There are always only averages and theoretical calculation quantities that can be used as a basis for such calculations.
But other factors also play a role on the climbing wall. These represent the X or the unknown in any equation, however good. What use is it if the climbing rope could have held its own weight and the added drop weight if a knot had been knotted incorrectly?
The Fall Factor in the Test
The standard testing of Edelrid*, for example, is based on fall heights of almost five meters and rope lengths of almost three meters. The fall factor that can be calculated with this is assumed to be 1.7.
This is intentionally a heavy fall load, which usually occurs rarely during climbing. However, this offers a certain safety reserve, which is included in the test result. When testing with single or twin ropes, a weight of 80 kilograms (176 pounds) is dropped into the rope in the drop test system until it breaks.
For half ropes, weights of 55 kilograms (121 pounds) fall into the climbing rope until it breaks. Each half rope must withstand at least five such standard falls. With twin ropes there are 12 standard falls. Due to the predefined test conditions, the climbing ropes should actually be able to withstand more than that.
The Impact Test in the Test
In addition to the norm fall test, an impact test is also always carried out. The term “impact force” is used to measure the maximum energy that can act on the drop weight during a standard fall.
The more elastic the climbing rope is, the sooner this energy can be partially captured and dissipated. When the impact is very high, you perceive the fall as more violent. This also increases the release of energy that acts on the climbing rope and the safety chain used.
Single and twin ropes must have an impact force of 12 kN. This means that you can carry a maximum weight of 1200 kilograms (2646 pounds). Half ropes must have a maximum impact force of 8 kN. This means a maximum payload of 800 kilograms (1764 pounds).
Static Test Arrangement vs Dynamic Reaction
All well and good – but under real conditions, such measurements are questionable or irrelevant. In such experimental arrangements, the climbing rope is fixed statically.
On a climbing wall, however, it is caught dynamically in the event of a fall. So the fall energy is absorbed quite differently than in the test laboratory.
This is due to the safety devices used to slow down the climbing rope. In addition, a responsive climbing partner or own measures to help cushion the fall can create better and more dynamic conditions.
Therefore, the partner check is just as important a measure as practicing one’s own behavior in crisis situations. Because when using certain backup devices, you have to act against your own instincts.
The Elongation in Use
The term service elongation is used to describe the elongation of climbing ropes that occurs under fall conditions or static loads such as the lifting of material.
The procedure for rope testing is as follows: In the first test, the climbing rope is loaded with 80 kilograms (176 pounds). A rope length of one meter is then marked with a 5-kg (11 lbs) preload. Now the load is again placed on an 80 kg (176 lbs) load. All that lies beyond the marked 100 centimeters is the rope elongation in percent.
Single and twin ropes may have a maximum static elongation of 10 percent, half ropes a maximum static elongation of 12 percent.
To climb safely, however, dynamic rope elongation is more relevant. It tells us more about the braking behavior of climbing ropes. The dynamic strain is measured at the first standard fall. This is about how the rope length is extended in the event of a crash.
The dynamic elongation value of a climbing rope must not exceed 40 percent.
The dynamic elongation of climbing ropes is often misjudged.
Climbing ropes with large interception joints have low static and dynamic elongation. However, with a small impact force, you will experience a high dynamic elongation. The stretch reserve is achieved by artificial shrinkage of the climbing ropes in the autoclave. The more often a climbing rope is heavily loaded, the sooner its stretchability is exhausted.
Attention: You have to take care of your safety when climbing! The information on climbtheearth.com only helps you to learn. Before you climb, you should make sure that you have been properly instructed by an expert and that you follow all safety precautions.
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