## / Rope melting rope through friction

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Hiya. Question for the floor.

There was an incident at the wall tonight where a climber was seconding a route I led which was basically vertical - roof - vertical. Where the rope went thought the roof, the rope was horizontal before heading up a headwall to the lower off.

Another climber was leading an adjacant route which crossed mine at the roof, and decided to move my rope (i.e. the one the second was attached to) and climb through the quickdraws it was attached to and behind the rope itself.

This meant that if that climber fell, their (moving, as they fell) rope would cross, and load with body weight directly across my rope and continue moving until their climber came to a halt.

i.e. loop one rope around another, load it with with body weight, and then accelerate the top rope at 9.8ms2.

My understanding is that this would melt the non-moving rope in short order - perhaps as litte as 3-5m of movement.

This:

and this:

support my view (the first mentioned 3-4m of movement), but I was wondering if anyone had done any tests on climbing rope to see how quickly a rope will melt through if another rope - loaded with body weight - is accelerated at gravity either across it or looped around it (the latter obviously being more critical).

As it happened I shouted at the person seconding (i.e. the person I was belaying) to stop climbing and shouted a lot of things, some of which were printable, at the person about to cross behind my rope to stop them doing so. The potential for disaster was therefore averted.

However it has got me thinking - we avoid nylon to nylon contact as we all know that a moving rope can melt though a static rope it crosses - but has anyone done any tests to determine how much rope-on-rope friction can be withstood by your average climbing rope when the moving rop is either loaded with body weight or unloaded?

Comments welcome. If they concern the behaviour of the other climber then trust me, he got the message ;-) Even his belayer apologised and said she didn't realise what he was doing until I started shouting, but if she had realised she would have stopped him.

I would be really interested in a response from rope manufacturers or simlar who I would imagine have actually done this kind of test.
In reply to John_Hat: what you describe (if I am reading it right) is either very poor route design and/or climber stupidity (theirs not yours). not particularly something that would concern me on a day-to-day climbing basis hence not really worth testing the ropes for.

All parties present including wall staff (who had a word with the climber concerned) agreed that the other climber was the cause of the issue. That's not really the question I was trying to ask, sorry if I put it wrong. To a certain extent its irrelevent - incident over and done with, no-one died.

Whilst I absolutley appreciate that it is a rare, unlikely occurance, enough people do silly things with their ropes that I would have thought that someone would have done the test somehere, sometime.

If nothing else, some manufacturers almost make a habit of testing their equipment for rare, unlikely events!
In reply to John_Hat: i dont think there is one specific test for stupidity.
> (In reply to John_Hat) i dont think there is one specific test for stupidity.

Not disagreeing but I'm not going to be too critical. We've all done things that were not a particularly bright idea and we've all made misjudgements. He without sin cast first stone, etc. I don't know the guy concerned and this might be the first error in many decades of blameless climbing.

Like I say, all I'm asking is whether anyone has done any testing on ropes and how easy (or hard) it is to melt through them with another rope.

Failing that, I'm trying to work out whether I might try and set up a test rig myself.

This is a report into the ropes used in Dan Osman's fatal accident: -

Not sure how official it is, but it does indicate that 'rope against rope' was the major contributory factor to the system failure.

DO's accident involved him falling several hundred feet at terminal velocity before loading his rope. Your scenario comes a bit short of that!

I would have thought the tests have been done as we know ropes melt but it’s hard to see what practical use the information would be.

#3 HOW TO CUT A ROPE WITHOUT A KNIFE

Many climbers carry a pen knife on their harness for cutting rope (or belay loop) for self rescue, but a lighter alternative is to carry a short length of 2mm perlon cord, which can be clipped in with your prusik loops. To cut a rope or a sling, simply rap the cord once around the material you want to cut, then pull it backwards and forwards until it melts through it – which takes about 2 seconds!

From here:

http://www.andy-kirkpatrick.com/articles/view/avoiding_the_void

If you can cut rope so easily with thin cord, I'm sure you can cut it without much more difficulty with thicker cord!

> ...... short length of 2mm perlon cord, which can be clipped in with your prusik loops. To cut a rope or a sling, simply rap the cord once around the material you want to cut, then pull it backwards and forwards until it melts through it.... >

Since the cord is only 2mm and the rope will be at least 6 or 7mm wouldn't the 2mm melt first?

As an aside, why are the first couple of paragraphs on his website written against a background which makes it almost impossible to read?

> Since the cord is only 2mm and the rope will be at least 6 or 7mm wouldn't the 2mm melt first?

Give it a try yourself, and see.

(One reason it doesn't is that the 2mm cord is moving, whilst the rope is fixed.)
>
> Since the cord is only 2mm and the rope will be at least 6 or 7mm wouldn't the 2mm melt first?
>

No, because the rope is static and the cord is moving. So the heat generated is focused in one spot on the rope, but spread along the length of the cord. That's enough to melt the rope. Try it, it's surprisingly easy, especially if the rope is held under tension. Similar technique used to cut through zip ties (or similar...) with a shoe lace etc.

The wear & tear would be spread out over a length of the thin cord but concentrated around the circumference of the rope.
I'm fairly sure the situation the OP described is bloody dangerous. You can severely damage a sling this way and I'd think by extension you could damage or cut a rope this way.
> [...]
>
>
> Try it, it's surprisingly easy, especially if the rope is held under tension. Similar technique used to cut through zip ties (or similar...) with a shoe lace etc.

It's the tension that is possibly the crucial thing. I used to do a little exercise on courses where I put a loop of old rope around a gatepost, threaded a climbing rope through it and got a group to run away with one end whilst 'gently' belaying the other end. In my experience the rope loop generally snapped with about 10m of rope pulled through it. Unscientific I know!
In reply to Andy Say: Makes sense, otherwise when you pulled a rope down from a bit of abseil cord you'd end up cutting through the cord. As it is, you usually don't see anything other than very minor melting of the cord sheath, if that.
> (In reply to Andy Say) Makes sense, otherwise when you pulled a rope down from a bit of abseil cord you'd end up cutting through the cord. As it is, you usually don't see anything other than very minor melting of the cord sheath, if that.

I don't think you read Andy's post properly.

Abseil tat does burn a bit each time a rope is pulled thro it.
Thats why a krab or maillon is preferable to take the friction.
Try lowering off instead of abbing off a fixed sling and you will soon understand his post!

Another possible situation of rope on rope is a factor 2 fall onto a multi pitch belay. A good reason to clip a runner above the belayer for the leader on the next pitch.

Not strictly the same thing but had an interesting nylon-on-nylon melting experience back in 1996, although not rope-on-rope; instead rope-on-Whillans Harness. I think the principle is probably similar though.

We were at the top of The Wand on Creag Meaghaidh and my climbing partner was leading through on the final easy slopes to the summit plateau. She'd nearly reached horizontal ground and was almost a rope length out when the whole slope avalanched. Carried down at speed she picked up momentum and became airborne, flying over the top of my head as the avalanche poured over and around the belay, and she fell back down the route like a bungee jumper. Thankfully the belay held and she was unscathed and able to climb back up and we got off the route second go.

The tie-in knot in my old Whillans had been cinched so tight (or so I thought) that I couldn't actually get it undone so just took the harness off and stuffed it and the rope in the 'sac and we went home.

It was only the next morning on closer inspection that I discovered why the tie-in was so difficult to undo - the rope had melted due to intense friction and hidden beneath the Whillans nylon tie-in loops there were only two strands of inner core left intact.

That was all that had stopped me from detaching from the belay and following her on a one-way journey to the bottom.

I used to happily and recklessly climb on a single 9 mm rope in winter quite a lot in those days. Needless to say, although melting ropes are a rare occurrence, as has been pointed out by others, I've always used two ropes since.

And retired the Whillans Harness...

Erm, Excuse me? You on the wrong thread?

The thread is actually a sensible gear-related question about people's experience of the resistance (or otherwise) of rope to friction and heat.

I can assure you that the person I am climbing with (a friend) being put at risk of injury is not something I "love" nor do I find it "interesting". The opposing belayer was shaking after the incident, as was I.

I am assuming that you are trying to stir up trouble. I think you can rest assured that if you had made the above comment in earshot of me, the person I was climbing with, or her boyfriend, or the opposing belayer one of us and more probably all four would have made absolutely sure you regretted opening your mouth.

> [...]
>

> Try lowering off instead of abbing off a fixed sling and you will soon understand his post!
>

That could be one very brief flash of understanding. Should that suggestion come with a health warning....
In reply to Rick Graham: Thanks, but I did understand his post - perhaps you didn't understand mine? My post indicated that without tension (ie pulling an abseil rope rather than bodyweight/lowering) you would only see very slight damage to the ab cord.
>
> Erm, Excuse me? You on the wrong thread?
>
> The thread is actually a sensible gear-related question about people's experience of the resistance (or otherwise) of rope to friction and heat.
>
> I can assure you that the person I am climbing with (a friend) being put at risk of injury is not something I "love" nor do I find it "interesting". The opposing belayer was shaking after the incident, as was I.
>
> I am assuming that you are trying to stir up trouble. I think you can rest assured that if you had made the above comment in earshot of me, the person I was climbing with, or her boyfriend, or the opposing belayer one of us and more probably all four would have made absolutely sure you regretted opening your mouth.
>

John,

To be fair the scenario you described in your post might have resulted in your climbing partner being pulled off the wall. They might even have been hit by a falling climber. They are real risks.

There is less than a snowball in hells chance that your ropes would have become intertwined in such a way that a tensioned loop of your rope would have a tensioned loop of the pillock's running across it in such a way, and for such a duration, that your rope would have been melted through. I really believe this to be true. Just think through the situation you describe. How is the rope of the falling climber going to be suspended from 'your rope' whilst your rope is 'static'? And, of course, the minute he had clipped a subsequent bolt - drama pretty much over.

By the way I'd give the route setters a thorough going over unless of course 'he' was off route
>
> Yes it's wrong and incredibly rare to happen.
>
> But you love the drama, I think it probably made your life a little but more interesting.

You cheeky little tinker.

p.s. I think you meant 'bIt'?
> My post indicated that without tension (ie pulling an abseil rope rather than bodyweight/lowering) you would only see very slight damage to the ab cord.

In agreement then

Just wanted to make sure folk realised that abseil tat/slings/rope deteriorate with every use.

The abseil point above Abraxas on Dow a few years ago was a single rope thread. It had burnt over halfway through. Some bright spark had hidden the bad bit behind the block. A few seconds very well spent checking its full length.

>
> There is less than a snowball in hells chance that your ropes would have become intertwined in such a way that a tensioned loop of your rope would have a tensioned loop of the pillock's running across it in such a way, and for such a duration, that your rope would have been melted through. I really believe this to be true. Just think through the situation you describe. How is the rope of the falling climber going to be suspended from 'your rope' whilst your rope is 'static'?

Hi Andy

I think the OP explained that the offending climber had climbed between the top rope, some clipped QD's and the wall. If he had fallen the OP's rope would have acted as a runner, not good.
> I think you can rest assured that if you had made the above comment in earshot of me, the person I was climbing with, or her boyfriend, or the opposing belayer one of us and more probably all four would have made absolutely sure you regretted opening your mouth.

>
> [...]
>
> Hi Andy
>
> I think the OP explained that the offending climber had climbed between the top rope, some clipped QD's and the wall. If he had fallen the OP's rope would have acted as a runner, not good.

That's the idea I got.
And xplorer's post was a bit shoddy but par for the course with him. I might be a grumpy old man now but if I was that negative at 27 I'd be getting treatment.

E
Rick; I got that. But ask yourself; if the offending climber had lobbed at the crucial point on the wall (i.e had no bolt clipped after his transgression and fell so that John's rope was the 'runner') AND had managed to drop so that John's rope was pulled down from the draw it was clipped into (if it was) so that it formed a static loop AND their belayer had let them go so the rope ran relatively free but under tension so that friction was produced just how far is said offending climber going to have fallen?

I will restate my belief that in the situation described a single, dynamic rope is just not going to be melted through.

BUT I would reiterate what I said above:

'To be fair the scenario you described in your post might have resulted in your climbing partner being pulled off the wall. They might even have been hit by a falling climber. They are real risks.'

Its just that I think that a melted rope is way, way down on the list of potential risks here

It might not melt it to failure. Agreed.

But it will damage the sheath at least, I would go ballistic if it happens to me.
> By the way I'd give the route setters a thorough going over unless of course 'he' was off route

I don't see how it's any fault of the setters. It isn't really possible to set varied and interesting routes without adjacent lines occasionally sharing a bit of real estate. (Depending on the wall architecture, it often isn't possible to set any routes without sharing a bit of real estate.) As, of course, real routes do all the time.

Me too. The lead climber wouldn't have got that far if I'd have been at the bottom.

E
> (In reply to Rick Graham)
> Rick; I got that. But ask yourself; if the offending climber had lobbed at the crucial point on the wall (i.e had no bolt clipped after his transgression and fell so that John's rope was the 'runner') AND had managed to drop so that John's rope was pulled down from the draw it was clipped into (if it was) so that it formed a static loop AND their belayer had let them go so the rope ran relatively free but under tension so that friction was produced just how far is said offending climber going to have fallen?
>
> I will restate my belief that in the situation described a single, dynamic rope is just not going to be melted through.

To be honest, this was part of the point of the OP. The guy fell about 5m when he came off, basically because he realised his situation, tried to reverse it, etc. As a result the quickdraw before the intersection with my rope toook the strain. Now I've heard/read that about 3-4m of tensioned rope against tensioned rope (as they both would be) is enough for meltthrough (see articles I linked to), and I wanted to know if anyone has done some tests to prove this. Or prove the opposite

I don't *think* it would go through, but don't know. In circumstances with much lower odds we play safe. I'd just like to know the odds a bit better.
> (In reply to Rick Graham)
>
> Me too. The lead climber wouldn't have got that far if I'd have been at the bottom.
>
> E

Tend to agree. Trouble was that because its quite an interesting three dimensional route I was watching my climber like a hawk and the topology means the other route actually starts about 10ft immediately behind me. I've not gone into great detail about the topology of the whole thing as its complex and if I tried no-one would get it and I'd lose the point of the post, also, really it doesn't matter, I was more interested in if the ropes loaded against eachother and he fell 5m then would my rope burn through.
> I was more interested in if the ropes loaded against each other and he fell 5m then would my rope burn through.

Lets see if Andy will volunteer to be the test weight!
>
> BUT I would reiterate what I said above:
>
> 'To be fair the scenario you described in your post might have resulted in your climbing partner being pulled off the wall.

You are right - Absolutely 100% would have happened. Especially as they weigh about 7st at a guess.

> They might even have been hit by a falling climber.

Nope, different direction, but you're not to know that.

> Its just that I think that a melted rope is way, way down on the list of potential risks here

erm, agreed. However, if your climber has just been pulled off the wall, then the rope then being melted through may (or may not) be a high risk, but because they are at this point dangling by said rope (having been pulled off the wall) its a catastrophic risk, and I'd like to know a bit more about the actual risks of meltthrough .
>
> [...]
>
> Hi Andy
>
> I think the OP explained that the offending climber had climbed between the top rope, some clipped QD's and the wall. If he had fallen the OP's rope would have acted as a runner, not good.

Yup, that's exactly it. If he'd climbed *over* my rope (so his rope and him were all further away from the wall than my rope) I'd have been a lot less bothered.

As said, though, really not bothered about the exact mechanics. I guess I could have simplified things by the OP being "I've heard that one rope running across another will melt through in 3-4m of movement, anyone got any stats to prove this?"

Ah well, 20/20 hindsight and all that!

No challenge there, Rick. I'll be the person hanging on the top rope: that's where true risk lies .

But I am getting very confused here.

The OP said: 'As it happened I shouted at the person seconding (i.e. the person I was belaying) to stop climbing and shouted a lot of things, some of which were printable, at the person about to cross behind my rope to stop them doing so. The potential for disaster was therefore averted.'

Now we are told: 'The guy fell about 5m when he came off, basically because he realised his situation, tried to reverse it, etc. As a result the quickdraw before the intersection with my rope toook the strain.'

But then further told: 'I was more interested in if the ropes loaded against eachother and he fell 5m then would my rope burn through.'

So 1. disaster was averted and there was no lob; 2. the guy actually fell 5m and the rope DID take the strain (but, presumably, didn't burn through) and 3. IF the guy had fallen what would have happened?

Have I got that right?

This is distracting me from work here but...

I think John Hat explained that the climber reversed a bit and fortunately fell off the right (safe) side of John's rope ie before he passed behind it.

John was worried what would have happened if the ropes had run over each other loaded.
>
> This is distracting me from work here but...
>
> I think John Hat explained that the climber reversed a bit and fortunately fell off the right (safe) side of John's rope ie before he passed behind it.
>
> John was worried what would have happened if the ropes had run over each other loaded.

^^ What he said. Sorry, have lurgy and my UKC habit has had to take second place to being in bed ill today...

Sure, Pit Schubert tested this (like nearly everything else!).
just search for Lowering and Abseiling Schubert and you´ll get the UIAA download with a table for the different thicknesses of cord/rope.

The wonders of Google and Jim Titt and Pit Schubert.

So about 5 metres for two 10mm ropes in a lowering situation possibly less with a leader fall involved. Scary.
John's original estimate of 3 to 4 metres was probably right all the time.

Off to Kendal Wall now to see if I notice the difference between real rock and plastic.