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Syd
Dec 7, 2012, 7:30 PM
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This article suggests:
"With only one exception no device available on the market is proven to be capable of stopping a climber in a reasonably long factor 2 fall and with most devices the belayer risks severe rope burns and loss of control even in considerably lower (less than 1) factor falls.
The energy involved in a long fall is considerable and the excess energy above that which the device can absorb is transferred into the belayers hand where it is converted into heat by friction. This rapidly causes the skin to heat up and friction burn whereupon an involountary reflex releases the grip. An acceptable amount of slip through a bare hand is variously given as 0.5m and 1.5m depending on the strength of the grip. Alternatively the Petzl Fall Simulator uses a threshhold of 1800J as the acceptable amount of energy before a rope burn warning is given ..."
"... the GriGri is the only device on the market proven in tests to hold factor 2 falls without damage to itself or the rope ..."
http://www.bolt-products.com/Glue-inBoltDesign.htm
1800 joules is generated when a 75kg climber falls 2.44 metres.
What sort of falls have people experienced in practice, that have resulted in belayer rope burn ?
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skellie
Dec 7, 2012, 8:11 PM
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Absolute BS.
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Co1urzz
Dec 7, 2012, 8:14 PM
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"Belay Gloves"
and 2/10 btw
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billcoe_
Dec 7, 2012, 9:48 PM
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In reply to: What sort of falls have people experienced in practice, that have resulted in belayer rope burn ?
skellie wrote: Absolute BS.
I suspect that due to slack and give in the system, it's more that lead falls do not generate as much on the system as we would think. If I'm pretty sure I may be needing to lock off a fall, I double up the belay biner (and worry over my body position more intently) which gives more friction. As ropes become smaller, I believe that the chance of burns increases.
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bearbreeder
Dec 7, 2012, 10:11 PM
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i know a few people who have burned their hands ... part of it is shitty belaying, i dont climb with those people ...
the other part is the belief that a standard ATC or other such is "suitable" for all ropes regardless of grip strength, size, the situation, etc ...
with thinner and slicker ropes ... i really dont believe the standard ATC is "suitable" any more for those situations unless youre using a thicker rope ...
as for high factor falls ... i tend to use an assisted locker on multi these days due to rockfall possibility, but it also helps in those "oh fcuk me" falls ...
if there is a strong possibility of a high factor fall on a tube device, use gloves or if you dont have any .... tie a quick knot farther down the rope, sure youll need to untie it after the hard moves, and it wont stop yr partner from hitting any ledge, but he wont get dropped the length of the rope ...
another possibility is the fixed point belay ... one of the less talked about issues is that the belayer will get SLAMMED into the rock in a high factor fall ... a fixed point belay, or tying in long can help that ... never tie in short on a belay where a big fall is possible, its very easy to slam into the wall and get hurt, and lose control of the rope ... tying in long can also reduce the fall factor ...
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donald949
Dec 8, 2012, 12:21 AM
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Well I have always tried to avoid the situation leading to a FF2. As in droping in gear straight away when leading off from the belay. If falling seams to be a possibility right off the bat from a bolted anchor, with out additional options, you could clip one of the anchor bolts as your first piece.
I would second the use of gloves, and the nonuse of the regular ATC for thin ropes.
Having taken some decent leader falls (Not FF2) with belayers ~1/2 my weight, it can be done. They will get lifted up, no soft catch required, just hold on.
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rgold
Dec 8, 2012, 1:52 AM
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skellie wrote: Absolute BS.
No, not B.S. Jim Titt knows more about the practical dynamics of climbing than most of the rest of the folks here put together.
Over the years, I've known of a number of cases of rope burn from belaying, and it wasn't always because of shitty belaying. Some of the people involved had very long recovery periods and a few had permanent damage.
Although special circumstances can intervene to make long fall-factor catches possible without rope burns, it just isn't generally possible with tube-style devices, most especially on the thinner and thinner ropes people are using nowadays.
The vast majority of climbing falls are relatively low fall-factor affairs further mitigated by all kinds of system friction, and this gives the impression that belay devices work statically in all cases. They don't, and it isn't news at this point, its been tested over and over with weights and with human belayers and human fallers too. Rope is going to run through the device on a high fall-factor fall with little systemic friction. So much so that some manufacturer's like Petzl essentially say (in their technique cartoons) that you can't hold a factor 2 fall with a tube-style device.
Of particular concern is the use of tube-style devices with half ropes. The belayer might have to catch a leader fall on a single 8.5mm or less strand. You can't even rappel comfortably with most devices on such single strands, much less hold leader fall impacts. If you have to double up carabiners to get enough friction to be comfortable on rappels, there is no way you'll hold a factor 1 fall without the rope running unless the system has lots of friction to help you out.
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skellie
Dec 8, 2012, 2:10 AM
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Okay, maybe; but serious rope burn on a FF1 fall? I don't think so. I've taken a few nearly FF1 falls in the gym (the routes are short, and yes, I landed lightly on the ground) with no problem except dodging the belayer, who I outweigh by 75 lb. I might add.
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rgold
Dec 8, 2012, 3:15 AM
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If you took a FF1 in the gym you hit the deck, and with full force too, because rope stretch is not part of the fall factor. You'd be headed to the hospital.
Gym falls often occur with the belayer standing a ways back from the wall and often with a nice loop of "Euro Slack" hanging down besides. You get the friction of a substantial bend around the first biner as the belayer is pulled forward and up. These things create the impression of a much bigger fall factor, as well as adding energy absorbing components that reduce the load the belayer has to hold by hand strength.
In any case, my FF1 reference was about climbers who can't rappel comfortably on a single strand, namely about using relatively thin ropes; not the sort of thing typical of the gym situation.
(This post was edited by rgold on Dec 8, 2012, 3:26 AM)
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JimTitt
Dec 8, 2012, 8:50 AM
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skellie wrote: Okay, maybe; but serious rope burn on a FF1 fall? I don't think so. I've taken a few nearly FF1 falls in the gym (the routes are short, and yes, I landed lightly on the ground) with no problem except dodging the belayer, who I outweigh by 75 lb. I might add.
Your also making the mistake of wandering into the Fall Factor trap, the question is not the impact force which is generally fall factor related but the energy in the fall which related to the fall distance.
A short (say 1m) FF2 is neither hard to catch nor will produce enough slip to burn, a 30m FF1 is another thing altogether.
Translating experience of short falls in the gym to outdoors is a mistake, falls of 30, 50 or even 100m are a distinct possibility unless you stick to sport climbing or well protected single pitch routes.
As Bearbreeder has pointed out the gripping ability of climbers in a belaying context is extremely variable and what works for one may well not work for another.
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Syd
Dec 8, 2012, 10:01 AM
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JimTitt wrote: Your also making the mistake of wandering into the Fall Factor trap,
I totally agree. As I pointed out "1800 joules (Petzl's burn threshold) is generated when a 75kg climber falls 2.44 metres. ". It's a matter of how much energy is dissipated in the system other than at the belay. If the route doesn't wander, and there's few clips and perhaps a newer slippery rope, the belayer will have to deal with higher amounts of energy in a fall.
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patto
Dec 8, 2012, 1:06 PM
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The only Factor 2 fall that I've read about heard about recently was this one.
http://www.chockstone.org/...p;PagePos=&Sort=
The belay ended up in a far worse state than the climber.
Thought I'd share a recent experience of a "Factor 2" fall with the hope that anyone interested may learn from it:
My gf and I were on "Lamplighter" at araps. It was her lead on the second pitch – her first on a multi pitch route, having not led much on trad before. As she left the belay I encouraged her to put in a piece early, or clip the top piece of the anchor on the way past. I was a bit surprised when she charged up a couple of metres without slotting anything but wasn’t concerned because she had been completely solid on lead for the whole trip and it looked like there were good slots for gear just above. It was a bit of an awkward stance – slabby, but without a customary grade 14 bucket to hang off – and after trying to place a nut or two, it was clear that those slots weren’t so good after all. She had skipped the fixed pin with my encouragement (“not really trustworthy”).
At this point she started getting a little flustered and poked in a small cam (a yellow WC Zero). It wasn’t aligned with the direction of the fall so I got her to move it, but apparently that made the cam lobes go crooked and offset and it looked dodgey so she moved it back. After all this frigging around she was getting pumped and stressed and suddenly the delicate moves in an increasingly airy position got a bit hard. She tried the next move but half fell, half retreated to rest on the cam. The cam ripped out and she went for the big plummet. Thankfully she sailed right out over the belay ledge, over the slab below and the ropes pulled her up on the steeper section below that.
She came up pretty much without a scratch, very fortunate given that she’d just taken a factor two fall which probably ended up being greater than six metres from top to bottom. It was by far the nastiest fall I’ve seen. She heroically got back up, and after a brief pause to check all limbs were intact, she charged on and led the pitch (one of the best pitches ever, though some of the gloss was probably taken off for both of us). This time she headed off with a bomber nut placed just above the anchors and also clipping the fixed pin above that.
Unfortunately I didn’t come off quite so well. I was sitting on the edge of the big comfy belay ledge, and as she sailed past the ropes ran over my leg. As the ropes came up tight, my leg got squished between the ropes and lip of the ledge. At first I thought my leg just had a deep, juicy bruise but it turns out that I had torn my hamstring as well. My guide hand (on the climber’s side of the belay device) got smashed into the rock. Just as predicted in the manuals, some rope slipped through the device and gave me some minor rope burn. I may also have damaged my sciatic nerve, possibly from the impact being transferred through my harness and into my lower back. My physio and I are still working out the exact nature of the damage to my leg and back, but whatever, it’s bloody painful and I may be out of action for a while.
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billl7
Dec 8, 2012, 2:17 PM
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donald949 wrote: If falling seams to be a possibility right off the bat from a bolted anchor, with out additional options, you could clip one of the anchor bolts as your first piece.
At the same time, I've always felt that I would rather catch an FF2 with its predictable-in-advance direction of pull than catch a nearly FF2 when the first and only piece is so close to the belayer. That's a lot of force on one anchor piece and much of it gets translated into the belayer being unmercifully jerked towards that anchor piece.
(As others say elsewhere, an even better idea is putting more rope in the system by having the belayer on a long leash. An upward pull piece or two (?) is another topic.)
And if the loading breaks the one piece, would the belayer have the time to change the direction of her brake hand in time if needed? Thinking of a tube-style device here. Seems very doubtful. Granted, you said to clip the bolt in this circumstance which I assume means one that is good for an near FF2.
Speaking of a near FF2 due to failed/no pro, confusion and rope burn: Late night rescue, Lovers Leap. It takes over 160 posts over two weeks with hints from others before the belayer realizes what happened and posts this jewell:
"I was belaying from my harness (with an atc) with the rope going from me through the anchors, through the belay device and they up to the climber. When he fell, each piece of gear pulled as he weighted it and he did bounce and their was plenty of air time. He fell below me and therefore my downward pull on the brake end of the rope was no longer doing its job. It took me dropping to the ledge where the rope once again had an upward direction from the atc over a flake on the outer edge of the ledge. There was a lot of rope passing through the belay device because of the suden change in direction of the pull of the rope."
Bill L
(This post was edited by billl7 on Dec 8, 2012, 2:19 PM)
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healyje
Dec 8, 2012, 8:42 PM
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Hmmm, never know what to make of this topic when it comes up with Jim Titt and Rgold's technical descriptions of the dangers.
But in thirty eight years of catching just a boatload of falls - many moderate-to-long, some on hip belays, and a couple directly onto me - I've just never encountered more than nominal (cinching) amount of rope running through any device and none through my hands (and believe me, I'd remember that).
I can only chalk it up to there being some sort of impedance mismatch between the numbers and the real world.
P.S. As ropes have gotten skinnier I have always scaled my belay devices accordingly and have a variety of small diameter devices including Kong's Ghost (my personal favorite), Petzl Reversino, and DMM bug (kinda scary).
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patto
Dec 8, 2012, 9:38 PM
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healyje wrote: Hmmm, never know what to make of this topic when it comes up with Jim Titt and Rgold's technical descriptions of the dangers. But in thirty eight years of catching just a boatload of falls - many moderate-to-long, some on hip belays, and a couple directly onto me -
I too have found it not aligned with MY real world experience however I trust the maths and the extensive testing Jim has done.
But for fun lets throw some numbers around. Lets say most 'big' falls are around FF 0.66 so that is 3 times less energy to rope ratio than a FF 2. Root(3) give 1.7x the force. Normally the fall force is reduced by at around 40% from the top draw, lets call this 50% to account for the other draws.
So now we are at 3.4x the force of a regular 'big' fall.
None of this accounts for the fact that peak tension is reduced by a dynamic belay as the belayer shoots skyward in a normal 'big' fall.
So are we now looking at 5x the peak force of a regular big fall? Ouch! Yeah i can see that slipping. And once the slipping starts it is going to continue for a while and the energy equations come back into play.
You don't need much slippage time for it to cause burns at those high forces. I've received some severe rope burns as an inexperienced hand on a yacht. It can get bad quickly and not even when holding on to somebody's life.
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Syd
Dec 8, 2012, 9:51 PM
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Interesting article.
I think the key with a FF2 is that there is no friction in the system to absorb energy. The belay device takes it all. The FF itself isn't important. It's the amount of energy absorbed by various points in the system other than the belay device.
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healyje
Dec 8, 2012, 10:17 PM
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I'm not implying their math is bad, just that it doesn't map to the real world very well.
And I'm also not saying holding some of those falls wasn't a brutal experience in several instances. What I am saying is I've never experienced any appreciable amount of rope run through a device or through my hands when hip belaying.
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JimTitt
Dec 8, 2012, 11:25 PM
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This is unfortunately the reality, one can go through an entire climbing career without any difficulties with belaying, I have as well.
BUT that doesn´t mean that another belayer combined with different ropes and belay devices won´t at some time and there are enough climbers with scars to prove it.
The primary reason for the cautions which a number of organisations, myself and other people give is because the newer climber is more likely to believe the reams of (misleading) advertising such as "extra holding power" "three times as much friction" etc and not, as our generation would automatically think `fuck me, if he runs it out any further we´re in the shit´.
In a day when 80m or longer, 9mm or less diameter ropes are becoming common we certainly are in a position where an increasing number of belayers won´t be able to stop long falls. The rope industry know this well, Beal simply recommend belay gloves as they know these sorts of falls are a danger to belayers and climbers and Petzl also consider their own devices unsuitable for larger falls particularly with low friction in the system.
The current belay devices are good for the job and as experience has shown us 99.99% of the time perfectly adequate, I use them as well and the position isn´t paricularly alarming (which is why the section quoted above was part of a technical article, not a sensational "belay plates kill") but a reminder that the systems we use aren´t 100% perfect is useful, especially for those who feel they want a slick device for fast paying out rather than one that will stop their partner.
Most of the danger can be easily avoided when one sees a possibility of a major fall by grabbing a karabiner and adding a re-direct to a harness leg loop or taking a simple wrap around the leg.
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JAB
Dec 8, 2012, 11:25 PM
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rgold wrote: Of particular concern is the use of tube-style devices with half ropes. The belayer might have to catch a leader fall on a single 8.5mm or less strand. You can't even rappel comfortably with most devices on such single strands, much less hold leader fall impacts. If you have to double up carabiners to get enough friction to be comfortable on rappels, there is no way you'll hold a factor 1 fall without the rope running unless the system has lots of friction to help you out.
Not sure I agree with this, unless you mean a situation where someone climbs on only one half rope. If you are belaying two ropes, catching a fall is quite easy, even if only one strand is loaded, since you are gripping both ropes anyway. A least my expereince is that half rope falls almost stop by themselves in my atc guide. But to be honest, the number of lead falls I've stopped on double ropes is probably less than 10.
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healyje
Dec 9, 2012, 12:36 AM
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In reply to: ...or taking a simple wrap around the leg.
While not taking an actual leg wrap, I can't think of a significant fall I've held trusting solely on device friction alone and not also braking hard across my hip as well. I don't trust any device that much.
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patto
Dec 9, 2012, 4:03 AM
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healyje wrote: While not taking an actual leg wrap, I can't think of a significant fall I've held trusting solely on device friction alone and not also braking hard across my hip as well. I don't trust any device that much.
Personally I've found that braking across my hip provides less friction that a proper 180 degree braking position. All the falls I've caught have been in a regulation 180 degree position.
That said when you are talking about factor 2 falls one of the other great dangers is the reversal of direction of pull. Rather than worrying about all this I take steps to ensure factor 2 falls don't happen.
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healyje
Dec 9, 2012, 4:11 AM
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patto wrote: healyje wrote: While not taking an actual leg wrap, I can't think of a significant fall I've held trusting solely on device friction alone and not also braking hard across my hip as well. I don't trust any device that much. Personally I've found that braking across my hip provides less friction that a proper 180 degree braking position. All the falls I've caught have been in a regulation 180 degree position.
Hmmm, personally that seems relatively inconceivable to me.
patto wrote: That said when you are talking about factor 2 falls one of the other great dangers is the reversal of direction of pull.
That's not been my experience in the several that I've held. Could you explain that further?
patto wrote: Rather than worrying about all this I take steps to ensure factor 2 falls don't happen.
Yeah, it's always better to avoid such situations, but shit does and did happen - particularly back in pre-cam days where a rack might consist of two sets of nuts and a couple of hexs.
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rgold
Dec 9, 2012, 4:42 AM
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JAB wrote: Not sure I agree with this, unless you mean a situation where someone climbs on only one half rope. If you are belaying two ropes, catching a fall is quite easy, even if only one strand is loaded, since you are gripping both ropes anyway. A least my expereince is that half rope falls almost stop by themselves in my atc guide. But to be honest, the number of lead falls I've stopped on double ropes is probably less than 10.
I think that having the second rope in you hands makes it harder to grip the rope that is running, not easier. The belay tests I've seen conducted with identical falls but different diameter ropes tend to confirm this; the belayers let out more rope slip with thinner ropes.
With regards to Joe's remarks, I have to say that my practical climbing experience agrees with his. I've held a whole lot of falls in 55 years of climbing, one of which was a factor 2 fall on a waist belay and the other of which was very close to factor 2, with the piece in question at my waist level and maybe 8 feet horizontally to the side, that one with a single 8.5mm strand and a reverso.
In the waist belay case, I think I had some help from the rope running over the edge of the belay ledge I was standing on. In the reverso case, a higher piece had blown and possibly reduced the total fall energy. In neither case was I conscious of the rope running, although I had gloves and might not have noticed a little slip. In the reverso belay I definitely experienced the "inertial effect" identified in the CAI belay tests in which the brake hand is drawn up to the device.
As Jim points out, once the rope tension exceeds what the belayer can hold and the rope starts to slip, the primary energy absorbtion mechanism is not rope stretch but friction through the device. This method mostly depends on the height of the fall and not on the fall factor. Both my catches were relatively short falls, I'd guess twenty feet or less, so that might have something to do with the low slippage too.
I also have quite a lot of impractical belay experience. Back in the day in the U.S. most climbers actually practiced dynamic belaying. The set-up we had on a catwalk in the bleachers of the now departed Stagg Field at the University of Chicago was essentially a UIAA drop test, both in terms of the weight and the fall factor.
Not a single climber, and there were many who were experienced as well as us noobs, succeeded in even stopping the falling weight on their first try. It crashed to the ground with a sickening thud as the belayer was rocketed up in the air until their anchor tie-in stopped them. With practice we all learned to hold the falls, but no one could do it without rope slipping around carefully pre-padded hips.
The lesson I took from this is that a severe fall with little systemic friction is a completely different experience from the run of the mill falls we tend to get. I hope no one here ever has to hold such a fall, and the chances are good that you will not. On the other hand, if the rare worst-case scenario does happen, I'd like to feel sure that the combination of gear and technique that I have is up to the task. I'm not sure that's true for half-ropes and a tube-style belay device.
I've got a year to go before I'm seventy. I'm slower and weaker than I used to be and than my brain thinks I am. So I've switched over to the Alpine Up for half-rope belaying. For me, assisted locking is the way to go for greater peace of mind. But even if you're not a half-demented geezer, you should think about whether you're really ready to hold a big impact with the gear you have.
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