How many falls can a climbing rope take? Short answer: A typical ISO approved climbing rope can take a minimum of 5 falls. But what is a fall according to the norm? There is a standardized way to test ropes for falling safety, and I will give you some more details in this post. After reading this post, you will not only understand how many falls a climbing rope can take but also why this number can be misleading. You’ll also know how to avoid falls which can damage your rope.
Whenever you take a fall climbing, your rope absorbs most of the fall energy. You probably noticed that climbing ropes stretch under tension, and this stretch is absorbing your fall energy. If the rope wouldn’t stretch, any fall higher then 3 feet would very likely result in devastating injuries to your spine and intestines, as your harness would stop you in fractions of a second – delivering the energy of the catch to your body.
The Fall Factor – a useful metric for testing ropes for safety
In order to absorb energy, the rope needs to stretch freely, i.e., the rope is only absorbing energy if it is not constrained by rock or cliff edges.
The fall factor is a ratio used to describe this: It is the distance fallen over the length of free stretching rope. If the length of the free stretching rope is very high, the number becomes small, and a small fall factor means good. Good as in Your body doesn’t absorb a lot of energy when the fall is caught. If the amount of free stretching rope is short, the fall factor becomes high, which is bad for you, as your body absorbs a lot of energy in this case. Lower fall factor means safer fall; it’s that simple. Keep in mind: A high fall with a lot of free stretching rope can sometimes be safer than a short fall with no free rope available. This is a little surprising to many people, as they think shorter falls are generally safer.
What happens if the fall factor is high?
If the fall factor is high, a lot of energy from the fall is not absorbed by the rope, which means it will be absorbed by the anchor and your body. Both are bad.
What fall factor is used to test ropes?
When you buy a rope, it says it can take X amount of falls. But how do manufactueres or the UIAA they come up with the number? They usually test the rope with a normed weight and falling distance, as well as given out rope. The given out rope for these “Normated falls” is 2.8m, with 0.3m of this between anchor and carabiner. The falling distance is a free 2.3m over the redirection point, which means that the free-falling distance is 2.3m + 2.8m – 0.3m = 4.8m. Take into account that these tests are done with a pre-stretched rope of 0.3m and you have a real free fall length of 4.5m for the test.
The given out rope is 2.5m without stretch, 2.8m with stretch, so the fall factor for this kind of normed fall is ranging between 1.7-1.8.
According to the ISO norm, it needs to be able to at least withstand 5 of these normed falls without snapping. So 5 is the minimum number for a rope to become ISO approved, with most ropes number of falls ranging between 5-10. If you want some more info about climbing rope norms, read on. here
Small Examples for Fall Factors
The illustrations show different falls with their fall factor; they are typical situations you can encounter.
Fall factor 0f 0.2 – pretty soft fall
The climber takes a 2m fall and has 10m rope given out. Fall factor is 2/10, 0.2, which is a soft fallen
Fall factor of 0.15 – high fall from the top part of the route
If the climber would be higher up and fell 3m, the fall factor would even be less than 0.2. Although he was actually higher and also fell further.
Fall factor of 1.0 a hard fall from low in the route.
Climber falls 3m but very low in the route; in this case, there was only 3m of rope given out. This would result in a fall factor of 3/3=1.0, which is a hard fall with a high fall factor.
Fall factor of 2.4 – a fall past the belay
This example can only occur in a multi-pitch route when the climber sails past the belay falling. With 6m of falling distance and only 3m of rope given out absorbing this fall, the fall factor is 6/3 = 2. Even worse: The initial reaction of most belayers is to take in slack when a fall like this happens. In terms of fall factor, this makes it worse: If the belayer took in 0.5m of slack rope, the fall factor would increase to 2.4, which is a hard fall, and above the fall factor of rope tests (which is between 1.7 and 1.8). This kind of fall is a problem, as you will never really know how much of a fall factor your rope can take, and what happens after this fall occurred – you basically overstressed the rope, and no one can really tell how many of these falls the rope can handle.
This also explains why most people are worried when multi-pitch climbing to fall past the belay, as it automatically increases the fall factor a lot.,
Falling in the real world – friction, overhangs, and ledges
Now that we talked about the fall factor, we have a usable tool to understand how forces acting on individual spots at the rope become stronger depending on the amount of free stretching rope.
Ideally, the rope should gradually stop a climber – in contrast to a binary full stop. But keep in mind that we did simplification on the examples above; in reality, the rope would run against the carabiner and the rock. Both reduce the ropes ability to absorb force to the full extent.
Have a look at a typical example with four 20 degree bends in the rope, which can often occur due to the way safety bolts are lined up on a route. In this case, because of the added friction, the fall factor is doubled from 0.3 to 0.6,
And these are just bolts, now imagine hard points of friction like ledges, lips or overhangs. If the protection has not been sufficiently extended by using a slip, it can double forces on the top piece of protection, leading to material failure.
Are longer falls always safer than short falls?
As we’ve seen, there are some situations where a long fall can be safer in terms of the fall factor. But don’t think that any long fall is safer in general. Quite the contrary, if you fall further chances are higher you hit something with more force like the ground, ledges or sections of rock that protrude. And you will swing further too, increasing chances to hit something while swinging.
Remember that fall factors can be high, transmitting a lot of force to the climber’s body, even when falling distances are short.
Tips to minimize falling factors and distances fallen
- If you lay safety, try to avoid bends in the rope as much as possible, as long as you can safely position protection gear.
- Make sure to protect your stance with multiple runners on multi-pitch routes
- Learn how to build proper stances, according to physics and law of force distribution
- Make sure to extend the top piece of protection, so you don’t introduce ledges and lips into your rope – otherwise, it may increase falling factors a lot
- Don’t leave out clips when you go sport climbing!!
- For belaying: If it’s safe and the climber is up high enough, keep the slack when the climber takes a fall and don’t hastily take in rope while he is falling. But don’t do this when the climber is near the ground – a hard fall that is caught BEFORE a ground hit is better than a “comfortable” fall that ends as a grounder.
Conclusion: Minimize the Fall Factor and keep track of big whippers
5-10 falls is the typical number of falls a rope can take. If you take longer falls, mark it somewhere in your climbing notebook, and make a mental note after more than 5 big falls to maybe replace the rope at some point. If you liked this article, write a comment. Feel free to have a look at some of our other gear-related articles. We reviewed the top climbing pants of 2020, tested the La Sportiva Tarantulace, a great beginner and allrounder shoe and have a cool guide to build a hangboard setup without drilling any walls in your home.