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dead_horse_flats


Mar 27, 2012, 8:22 PM
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Has a rope ever broke with no extenuating circumstances?
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Has a rope ever broke with no extenuating circumstances? More specifically, has a climber ever taken a fall and had the rope break because the force of the fall exceeded the breaking strength of the rope.

Typical extenuating circumstances that dont apply to this question:
--Rope cut by sharp edges in gear or rocks.
--Rope exposed to chemicals.
--Manufacturer defects like the disintegrating petzl ropes.
--dan osman.

And by rope, I mean a modern dynamic kernmantle rope.


majid_sabet


Mar 27, 2012, 8:42 PM
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they say at 6+kn, human body internally breaks apart so you are already dead when rope breaks


I forgot, I do have few cases in my upcoming book where rope broke due to age with fatality result but rope was very old (20+ years).


(This post was edited by majid_sabet on Mar 27, 2012, 8:59 PM)


JimTitt


Mar 27, 2012, 11:38 PM
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majid_sabet wrote:
they say at 6+kn, human body internally breaks apart so you are already dead when rope breaks


I forgot, I do have few cases in my upcoming book where rope broke due to age with fatality result but rope was very old (20+ years).

"They" say all sorts of rubbish but those who "know" consider 12g is the threshhold for potential serious injury and so the UIAA and CENORM set the upper impact force for a rope at 12kN.
For window cleaners the limit is different as no injuries are acceptable in a work environment.


bill413


Mar 28, 2012, 6:09 AM
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I have heard of one case of it happening. I did not see it myself, but received the story from one of the people involved.

Oh, on rereading the OP I see that all causes except excessive fall are ruled ineligible. Never mind.


(This post was edited by bill413 on Mar 28, 2012, 6:10 AM)


Partner drector


Mar 28, 2012, 8:36 AM
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dead_horse_flats wrote:
Has a rope ever broke with no extenuating circumstances? More specifically, has a climber ever taken a fall and had the rope break because the force of the fall exceeded the breaking strength of the rope.

Typical extenuating circumstances that dont apply to this question:
--Rope cut by sharp edges in gear or rocks.
--Rope exposed to chemicals.
--Manufacturer defects like the disintegrating petzl ropes.
--dan osman.

And by rope, I mean a modern dynamic kernmantle rope.

Dan Osman is a person, not a circumstance. Perhaps you mean rope-on-rope-friction as a circumstance?

The short-hand is cute but a little vague since you might have meant that either his insanity, charming personality, or white teeth, was a circumstance that could break a rope.

Dave


curt


Mar 28, 2012, 10:48 AM
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dead_horse_flats wrote:
Has a rope ever broke with no extenuating circumstances? More specifically, has a climber ever taken a fall and had the rope break because the force of the fall exceeded the breaking strength of the rope.

Typical extenuating circumstances that dont apply to this question:
--Rope cut by sharp edges in gear or rocks.
--Rope exposed to chemicals.
--Manufacturer defects like the disintegrating petzl ropes.
--dan osman.

And by rope, I mean a modern dynamic kernmantle rope.

I doubt it. At least I have never heard of such a thing happening.

Curt


dan2see


Mar 28, 2012, 11:17 AM
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Well when Wylie Coyote is swinging on one of his Acme Ropes, it sometimes snaps but only while swinging over 300 feet of air. Otherwise the rocks break off.

What I mean by this is: We often imagine the worst thing that could happen to us. We can mentally explore the envelope to find scenarios where such a disaster might occur. Some of us will even go further, and tell a story about it. It's great for the campfire.


potreroed


Mar 28, 2012, 11:56 AM
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I had the sheath of a brand new rope burst apart after a short fall on good gear with nothing sharp anywhere nearby. Never did figure out how it happened.


dan2see


Mar 28, 2012, 12:33 PM
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potreroed wrote:
I had the sheath of a brand new rope burst apart after a short fall on good gear with nothing sharp anywhere nearby. Never did figure out how it happened.

OK once we were half-way up the mountain, with a friend's rope, and the sheath was torn open. But we used it that way, just watched out to avoid any obvious abuse.

This and other incidents show how a climbing rope is actually multi-redundant. The core strands are each more than capable of carrying you safely, and you'll live. It just looks bad. Of course when you're back in the city, then it's time to buy a new rope!


Partner cracklover


Mar 28, 2012, 1:16 PM
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dead_horse_flats wrote:
Has a rope ever broke with no extenuating circumstances? More specifically, has a climber ever taken a fall and had the rope break because the force of the fall exceeded the breaking strength of the rope.

Typical extenuating circumstances that dont apply to this question:
--Rope cut by sharp edges in gear or rocks.
--Rope exposed to chemicals.
--Manufacturer defects like the disintegrating petzl ropes.
--dan osman.

And by rope, I mean a modern dynamic kernmantle rope.

How would you imagine this to happen? I mean, the ropes hold a half a dozen of the hardest falls possible in the lab, so... without extenuating circumstances allowed, I'm just not sure what you are expecting to hear?

GO


dead_horse_flats


Mar 28, 2012, 2:05 PM
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potreroed wrote:
I had the sheath of a brand new rope burst apart after a short fall on good gear with nothing sharp anywhere nearby. Never did figure out how it happened.

Can you recall the brand of rope?


petsfed


Mar 28, 2012, 5:28 PM
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JimTitt wrote:
majid_sabet wrote:
they say at 6+kn, human body internally breaks apart so you are already dead when rope breaks


I forgot, I do have few cases in my upcoming book where rope broke due to age with fatality result but rope was very old (20+ years).

"They" say all sorts of rubbish but those who "know" consider 12g is the threshhold for potential serious injury and so the UIAA and CENORM set the upper impact force for a rope at 12kN.
For window cleaners the limit is different as no injuries are acceptable in a work environment.

12g for an average person is about 8.5kn, by the way.


JimTitt


Mar 29, 2012, 1:54 PM
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petsfed wrote:
JimTitt wrote:
majid_sabet wrote:
they say at 6+kn, human body internally breaks apart so you are already dead when rope breaks


I forgot, I do have few cases in my upcoming book where rope broke due to age with fatality result but rope was very old (20+ years).

"They" say all sorts of rubbish but those who "know" consider 12g is the threshhold for potential serious injury and so the UIAA and CENORM set the upper impact force for a rope at 12kN.
For window cleaners the limit is different as no injuries are acceptable in a work environment.

12g for an average person is about 8.5kn, by the way.

12g is 12kN for the 100kg climber represented by the 80kg solid standard test weight.


petsfed


Mar 29, 2012, 3:06 PM
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I'm 180lbs, and I'm fuckin' heavy for a climber. 100 kg is 220 lbs, which means a full rack and a full pack on a heavy dude so while the standard makes sense as it is overengineered, you're high if you think 12kn is approximately 12g for the average climber.


potreroed


Mar 29, 2012, 5:10 PM
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dead_horse_flats wrote:
potreroed wrote:
I had the sheath of a brand new rope burst apart after a short fall on good gear with nothing sharp anywhere nearby. Never did figure out how it happened.

Can you recall the brand of rope?

It was a Beal, but this happened 30 years ago, and yes, they gave me a new rope.


majid_sabet


Mar 30, 2012, 10:22 PM
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petsfed wrote:
I'm 180lbs, and I'm fuckin' heavy for a climber. 100 kg is 220 lbs, which means a full rack and a full pack on a heavy dude so while the standard makes sense as it is overengineered, you're high if you think 12kn is approximately 12g for the average climber.

I guess our Jimmy does not know that climbers do carry 20/30 lbs of gear on them so the 100/110kg is a reasonable weight to testing


danabart


Mar 31, 2012, 6:13 AM
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potreroed wrote:
I had the sheath of a brand new rope burst apart after a short fall on good gear with nothing sharp anywhere nearby. Never did figure out how it happened.

I had the same thing happen to me. We assumed it was a bad match of a thin rope and a carabiner with a very narrow profile - one of the old Lowe 33s that were briefly popular. No obvious core damage, but very scary to hear a loud cracking sound and see six fet of exposed core and lot of rope fluff from the broken sheath flying around in the air.


meanandugly


Mar 31, 2012, 11:41 AM
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Hmmmmmm...properly made rope, used in the way it was designed...Nope. All things that would cause a rope failure would be "extenuating circumstances".


base_jumpx


Mar 31, 2012, 5:20 PM
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meanandugly wrote:
Hmmmmmm...properly made rope, used in the way it was designed...Nope. All things that would cause a rope failure would be "extenuating circumstances".


I've seen it happen when base jumping


meanandugly


Mar 31, 2012, 5:23 PM
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Base jumping with a kernmantel rope?


petsfed


Mar 31, 2012, 5:30 PM
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majid_sabet wrote:
petsfed wrote:
I'm 180lbs, and I'm fuckin' heavy for a climber. 100 kg is 220 lbs, which means a full rack and a full pack on a heavy dude so while the standard makes sense as it is overengineered, you're high if you think 12kn is approximately 12g for the average climber.

I guess our Jimmy does not know that climbers do carry 20/30 lbs of gear on them so the 100/110kg is a reasonable weight to testing

Expedition usage is NOT an accurate reflection of "average" usage, so the claim that 12g is equal to 12kN for the average climber is clearly false. If they wanted to minimize the possibility of injury to the average climber (not some worst case scenario), they'd set it at around 9kn, if not lower.

All of that said, the human body can actually handle 12 kn for very brief periods of time as its not necessarily the acceleration so much as the duration, and there's no handy rule of thumb to figure that one out.


(This post was edited by petsfed on Mar 31, 2012, 5:34 PM)


curt


Apr 1, 2012, 8:59 PM
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base_jumpx wrote:
meanandugly wrote:
Hmmmmmm...properly made rope, used in the way it was designed...Nope. All things that would cause a rope failure would be "extenuating circumstances".


I've seen it happen when base jumping

You might want to explain exactly what happened--so we don't continue to think you're nuts.

Curt


Express


Apr 1, 2012, 9:58 PM
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You guys are really good at the metric system.

Acceleration due to Earth gravity: g = 9.81 m/s^2

Units of force (Newton): 1 N = 1 kg * 1 m/s^2

1 kg falling under earth gravity ----> 9.81 N

80 kg under 12g of acceleration = 80 kg * (12 * 9.81 m/s^2) = 9418 N = 9.418 kN


USnavy


Apr 1, 2012, 11:43 PM
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dead_horse_flats wrote:
Has a rope ever broke with no extenuating circumstances? More specifically, has a climber ever taken a fall and had the rope break because the force of the fall exceeded the breaking strength of the rope.

Typical extenuating circumstances that dont apply to this question:
--Rope cut by sharp edges in gear or rocks.
--Rope exposed to chemicals.
--Manufacturer defects like the disintegrating petzl ropes.
--dan osman.

And by rope, I mean a modern dynamic kernmantle rope.
First, we need to define what "rope failure" actually is. No, I dont think anyone has ever completely severed a rope in half from "too big" of a lead fall (aside from failure due to sharp edges or chemical alteration). However complete sheath failure, resulting in serious injury, has occurred. When rappelling a 11mm static rope in Yosemite this happened to me:



The rope deshethed as my belay device hit a worn section of the rope. I slid down the rope until the sheath jammed in my belay device, stopping me. A few of the core strands failed as my Trango Cinch attempted to jam the core strands, but failed to. The rope could have failed and if it had, my death/ injury would have been a result from rappelling on an excessively worn rope, which seems to meet your qualifications. Someone in Hawaii had the same thing happen to her a few years back. She was rappelling on a rope and the sheath failed sending her 60 feet to the deck. The rope did not completely fail, however, because belay devices grab onto the sheath of the rope, she just slid down the core strands to the ground. I did not have that problem because in my case, the sheath failed in the belay device, not after the belay device. Had the sheath severed after it passed through my belay device, it would have been pinching the detatched sheath instead of the core strands and I would have likely decked (think of trying to rappel by holding onto the rope through a banana peel)


(This post was edited by USnavy on Apr 1, 2012, 11:48 PM)


meanandugly


Apr 2, 2012, 12:58 AM
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Sure you met the boundaries the OP set, but rapping on a worn rope= "extenuating circumstances". I've blown a couple of sheaths to, but that was in my 1st decade of climbing, I have since decided not to create own "extenuating circumstances". ;)


ptlong2


Apr 2, 2012, 6:23 PM
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petsfed wrote:
...the claim that 12g is equal to 12kN for the average climber is clearly false.

Nobody has made a claim about the average climber except for you.

I believe the 12g number originally came from military parachute jump injury statistics. Granted, for a given fall and rope a lighter person will experience a higher peak deceleration. But how deceleration and body mass scale with respect to injury rate is not obvious, at least not to me.


petsfed wrote:
If they wanted to minimize the possibility of injury to the average climber (not some worst case scenario), they'd set it at around 9kn, if not lower.

But there are tradeoffs to consider. In the case of the military jumper a lower force means waiting longer for the parachute to open. For a climber it means the rope stretches further.

Nonetheless, many ropes already meet your criteria.


petsfed wrote:
...the human body can actually handle 12 kn for very brief periods of time...

I just finished reading Mary Roach's recent book and she wrote about this. Back in the day a guy named Stapp and his associates rode rocket carts that decelerated very abruptly. Mr. Stapp himself reached a peak of over 40g for a short period of time. It's funny, there's a guy who is planning to beat Kittinger's 100,000+ foot parachute jump but I haven't heard of anyone who wants to take on the G-force record.


dead_horse_flats


Apr 2, 2012, 7:20 PM
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USnavy wrote:
dead_horse_flats wrote:
......
First, we need to define what "rope failure" actually is. No, I dont think anyone has ever completely severed a rope in half from "too big" of a lead fall (aside from failure due to sharp edges or chemical alteration). However complete sheath failure, resulting in serious injury, has occurred. When rappelling a 11mm static rope in Yosemite this happened to me:

[img]http://img853.imageshack.us/img853/7739/img0203tp.jpg[/img]

The rope deshethed as my belay device hit a worn section of the rope. I slid down the rope until the sheath jammed in my belay device, stopping me. A few of the core strands failed as my Trango Cinch attempted to jam the core strands, but failed to. The rope could have failed and if it had, my death/ injury would have been a result from rappelling on an excessively worn rope, which seems to meet your qualifications. Someone in Hawaii had the same thing happen to her a few years back. She was rappelling on a rope and the sheath failed sending her 60 feet to the deck. The rope did not completely fail, however, because belay devices grab onto the sheath of the rope, she just slid down the core strands to the ground. I did not have that problem because in my case, the sheath failed in the belay device, not after the belay device. Had the sheath severed after it passed through my belay device, it would have been pinching the detatched sheath instead of the core strands and I would have likely decked (think of trying to rappel by holding onto the rope through a banana peel)

Dang. Damned. Crap. That is basically the repetitive nightmare that I keep having, and why I asked this question. Would the moderator please delete USNavy's post and I'll pretend I never read this.

Isnt there something on this website that lets me block USNavy's posts?

Seriously tho, how old was the rope and how bad was the wear?


(This post was edited by dead_horse_flats on Apr 2, 2012, 10:03 PM)


dagibbs


Apr 3, 2012, 12:25 PM
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dead_horse_flats wrote:
USnavy wrote:
dead_horse_flats wrote:
......
First, we need to define what "rope failure" actually is. No, I dont think anyone has ever completely severed a rope in half from "too big" of a lead fall (aside from failure due to sharp edges or chemical alteration). However complete sheath failure, resulting in serious injury, has occurred. When rappelling a 11mm static rope in Yosemite this happened to me:

[img]http://img853.imageshack.us/img853/7739/img0203tp.jpg[/img]

The rope deshethed as my belay device hit a worn section of the rope. I slid down the rope until the sheath jammed in my belay device, stopping me. A few of the core strands failed as my Trango Cinch attempted to jam the core strands, but failed to. The rope could have failed and if it had, my death/ injury would have been a result from rappelling on an excessively worn rope, which seems to meet your qualifications. Someone in Hawaii had the same thing happen to her a few years back. She was rappelling on a rope and the sheath failed sending her 60 feet to the deck. The rope did not completely fail, however, because belay devices grab onto the sheath of the rope, she just slid down the core strands to the ground. I did not have that problem because in my case, the sheath failed in the belay device, not after the belay device. Had the sheath severed after it passed through my belay device, it would have been pinching the detatched sheath instead of the core strands and I would have likely decked (think of trying to rappel by holding onto the rope through a banana peel)

Dang. Damned. Crap. That is basically the repetitive nightmare that I keep having, and why I asked this question. Would the moderator please delete USNavy's post and I'll pretend I never read this.

Isnt there something on this website that lets me block USNavy's posts?

Seriously tho, how old was the rope and how bad was the wear?

Just looking at the rope, it looks quite old. Gone grey from UV exposure, among other things.

What that post tells me is not that ropes break, but that you should take extra care with fixed ropes, because you don't know how long they've been installed.


Kinobi


Apr 4, 2012, 1:04 PM
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A deshethled rope should not break.
Sorry, in Italian...
http://www.caipadova.it/articoli/singola-news/list/2011/10/18/usura-delle-corde-in-arrampicata.html
E


tower_climber


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ptlong2 wrote:
I believe the 12g number originally came from military parachute jump injury statistics. Granted, for a given fall and rope a lighter person will experience a higher peak deceleration. But how deceleration and body mass scale with respect to injury rate is not obvious, at least not to me.

The figure I have heard and seen referenced in regards to falling is 12kN. The military parachuting experiments showed that organ displacement occurred at 12kN. I have not heard g-forces referenced in relation to these experiments.

In the following article, the researchers found that lumbar vertebrae suffered fracturing at an average of 6.5kN, though they state that spinal muscle and connective tissue would likely cushion and reduce peak impact forces in a real-world situation. In the study the majority of the specimens fractured at less than 9kN of peak load, though one set (21yo male subject) exceeded 15kN before breaking.

http://www.ncbi.nlm.nih.gov/.../janat00240-0080.pdf

Regardless: if you take a fall that registers more than 6kN of impact force it is going to hurt like a BITCH.


JAB


Apr 5, 2012, 5:03 AM
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Re: [tower_climber] Has a rope ever broke with no extenuating circumstances? [In reply to]
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I remember a Mythbusters episode, where they tested the brace position in airplane crashes. In this test, they put the minimum injury level at 50 G (i.e. less than that can lead to some injury but is not fatal).

Link here: http://kwc.org/...ler_brace_posit.html


ptlong2


Apr 5, 2012, 3:50 PM
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Re: [tower_climber] Has a rope ever broke with no extenuating circumstances? [In reply to]
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tower_climber wrote:
The figure I have heard and seen referenced in regards to falling is 12kN. The military parachuting experiments showed that organ displacement occurred at 12kN. I have not heard g-forces referenced in relation to these experiments.

The US military specification 9479A considers 12.1G to be the 5% "probability of injury level". This is according to Survivable Impact Forces on Human Body Constrained by Full Body Harness (which you can find at http://www.hse.gov.uk/...df/2003/hsl03-09.pdf).


tower_climber wrote:
In the following article, the researchers found that lumbar vertebrae suffered fracturing at an average of 6.5kN, though they state that spinal muscle and connective tissue would likely cushion and reduce peak impact forces in a real-world situation. In the study the majority of the specimens fractured at less than 9kN of peak load, though one set (21yo male subject) exceeded 15kN before breaking.

http://www.ncbi.nlm.nih.gov/.../janat00240-0080.pdf

There was a very wide spread of values. The female vertebrae fractured on average at around half that of the male vertebrae. It seems likely that there is a dependence on body mass which the study ignored.

It's also not clear to me how the force on the vertebrae they were measuring relates to the force on the climber as a whole (i.e. the rope tension).


billcoe_


Apr 25, 2012, 9:41 AM
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Re: [dead_horse_flats] Has a rope ever broke with no extenuating circumstances? [In reply to]
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dead_horse_flats wrote:
Has a rope ever broke with no extenuating circumstances? More specifically, has a climber ever taken a fall and had the rope break because the force of the fall exceeded the breaking strength of the rope.

Typical extenuating circumstances that dont apply to this question:
--Rope cut by sharp edges in gear or rocks.
--Rope exposed to chemicals.
--Manufacturer defects like the disintegrating petzl ropes.
--dan osman.

And by rope, I mean a modern dynamic kernmantle rope.

No

End of story. There's only extenuating circumstances when ropes fail and people get hurt or die. I was swinging on that very rope US Navy posts above about a month before he was. Extenuating circumstance there too.

There is always extenuating circumstances.


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