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Gear Failure on West Face Leaning Tower results in whipper.
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May 6, 2013
Start of Pitch 3
MIND = BLOWN
MIND = BLOWN
alleyehave
From San Diego, CA
Joined Jun 12, 2010
175 points
May 6, 2013
Start of Pitch 3
Shern, has the distance between the nose and the spine increased? Notify Mammut ASAP. alleyehave
From San Diego, CA
Joined Jun 12, 2010
175 points
May 6, 2013
alleyehave wrote:
Shern, has the distance between the nose and the spine increased? Notify Mammut ASAP.



not sure--anthony has the broken biner as a keepsake. I'll ask him.
Shern
Joined Oct 19, 2012
47 points
May 6, 2013
It doesn't take much of a fall factor to exceed the open-gate strength. If I have my entries right, I can get far below fall factor one with my favorite rope before combined forces drop below 8 kN:

Jay T's Force Calculator

Although I suspect a minor player in this accident, gri-gri's can produce higher forces than an ATC when catching a fall:

Geir Hundal's (see Myth 7) The Climbing Myth Busters

If the wall is curving outward, or the climber falls outward from a vertical wall, could be some wicked whip lash to a rope-side biner when:

  • the top draw is pulled out some;
  • which, as the rope goes taught, pulls the next-down draw out from the wall;
  • the top draw somehow separates from the rope (sling trapped in gate?);
  • the falling climber / rope slams down against the next "airborne" rope-biner;
  • which then rapidly accelerates (pendulums) towards the wall.

Edit to add about the whiplash experienced by a rope-end biner: Consider that Shern was pulled up and into the wall hard enough to bite his lip and lose his glasses (?). And his body has many many more times the mass of a biner which would react much much more quickly to be jerked around.

I'm sticking to the easy leads where, if I fall, I'm more likely to get hurt hitting something. ;-P (Wait, I think I already did that.)
Bill Lawry
From New Mexico
Joined Apr 16, 2006
1,604 points
May 6, 2013
Shern indicated on the RC.com thread (maybe here too)"the cam was maybe 5' below the climber. not sure of anthony's rope brand, but can find out. 10.5 diameter." Bill Lawry
From New Mexico
Joined Apr 16, 2006
1,604 points
May 6, 2013
Hopefully someone checks this ...

Using
  • rope impact force rating of 9.2 kN
  • the default friction factor of 0.3333
  • 30 feet of rope out

I only need a fall factor of 0.36 for a 155 lb climber to reach 8 kN on the top piece.

If 30 feet of rope was indeed out, that's a 10.8 foot fall ... really close to the cam-to-climber distance plus that again for the length of the initial fall.

8 kN is even more likely to be exceeded if only 25 feet were out and/or if the draw on the cam puts the catch point a couple feet lower than the cam. But we lose some of that if we need to add the length of rope between the leader's feet and his waist tie-in point.

Needless to say, these circumstances (or circumstances very close to the real ones) are uncomfortably close to the open-gate breaking strength of this biner.

All that said, Jay's force calculator is of course theoretical. I haven't read what assumptions he makes about things like a somewhat upwardly mobile belayer.
Bill Lawry
From New Mexico
Joined Apr 16, 2006
1,604 points
May 6, 2013
It seems highly unlikely that three biners would fail on the same fall (either unclipping or breaking) without either user error or a design flaw.. I assume the climbers are experienced if on a big wall and screwing up clipping the rope to a draw thee times in a row seems unlikely. Even though I'm a big fan of Mammut, I won't be buying those biners any time soon. T. Maino
From Denver, CO
Joined Jan 1, 2001
13 points
May 6, 2013
T. Maino wrote:
It seems highly unlikely that three biners would fail on the same fall (either unclipping or breaking) without either user error or a design flaw.


Three independent mechanisms would be amazing. It's possible there were just two independent mechanisms if the lower two failed in the same way: gate open.
Bill Lawry
From New Mexico
Joined Apr 16, 2006
1,604 points
May 6, 2013
yeah, the more I look at it, the more I think somehow the gates opened enough to basically create an open gate scenario which led to the failures.

Just for definition 'gate flutter,' a dangerous condition created by irregular impact forces generated by the climbing rope or contact with hard surfaces in a fall which momentarily opens the gate (and both lowers the breaking strength of the carabiner when open and potentially allows the rope to escape).

I think you ought to ditch the bent gates and go all wire gates, wire gates are much less likely to fall victim to gate flutter.

I'm especially thinking that since these bent gate biners were on the end of a long sling, maybe they managed to get the spine of the biner whipped against the rock and opened the gate.

Re the atc vs gri-gri debate, does anybody use an ATC on a wall? I don't usually advocate the use of gri-gri's especially for cragging and trad climbing, but if I'm belaying a 2 hour pitch, I'm using a gri-gri. I've even fallen asleep belaying before (maybe I need a partner that climbs faster)
John D
Joined Nov 24, 2010
21 points
May 6, 2013
John D wrote:
Re the atc vs gri-gri debate, does anybody use an ATC on a wall? I don't usually advocate the use of gri-gri's especially for cragging and trad climbing, but if I'm belaying a 2 hour pitch, I'm using a gri-gri. I've even fallen asleep belaying before (maybe I need a partner that climbs faster)

I need to add that I have done extremely little aid climbing (i.e., one pitch). But I have heard the same thing from more experienced folks about the desire for gri-gri's for long leads on aid.
Bill Lawry
From New Mexico
Joined Apr 16, 2006
1,604 points
May 6, 2013
OK, one of the pieces pulled. So only 2 biners actually failed.


Pretty much everyone I know uses a Grigri for wall belays these days.
Rob Dillon
Joined Mar 22, 2002
993 points
May 6, 2013
Russ
Re the atc vs gri-gri debate, does anybody use an ATC on a wall? I don't usually advocate the use of gri-gri's especially for cragging and trad climbing, but if I'm belaying a 2 hour pitch, I'm using a gri-gri. I've even fallen asleep belaying before (maybe I need a partner that climbs faster)

2 hour lead is nothing. On those 6 hour leads I'd put the rope under my head and pull out a few feet of slack. They pull on the rope, it jerks on my head, I wake up and they never see me sleeping. I'd also put a Jumar down the line a few feet from the belay as a third hand... well, the only hand if If I'm sleeping. This was using a Fig. 8 rig or an ATC.

As for the biners breaking... zero chance they broke because of whatever fall factor you math whizzes want to put on the fall. Biners break in normal climbing scenarios because they either get loaded with the gate open or trapped to the point where a torsional force is applied. Biners are designed to take a load basically only in perfect position. They can get trapped in a hanger, bent over an edge, or some other oddity that simply snaps them at a low force. In the spirit of internet speculation, I'd go with bad luck, open gates, the Devil needing more souls, and probably some other factor yet injected into the conversation.

Glad you dudes are OK! Weird for sure.
Russ Walling
From www.FishProducts.com
Joined Oct 5, 2004
3,276 points
May 6, 2013
ROFL!!!!! I'm glad to not b the only one who gets bored at belays. The 'jerk on my head' & 'well the only hand' thing is hilarious Ana Tine
Joined Dec 7, 2012
66 points
May 6, 2013
Russ Walling wrote:
As for the biners breaking.... In the spirit of internet speculation, I'd go with bad luck, open gates, the Devil needing more souls, and probably some other factor yet injected into the conversation.

I got ya worried, huh Russ. I mean, probably neither you nor I are as light as Shern's partner. ;-)

No, really, you are right that the precise way it failed is hard to say.
Bill Lawry
From New Mexico
Joined Apr 16, 2006
1,604 points
May 7, 2013
The traverse out to the Yellow Ridge on the Dogsti...
Caprinae monkey wrote:
There is a site you can check what kN force the falling climber generated: myoan.net/climbart/climbforcec...


That calculator is completely bogus---it can't even get the fall factor right, and who knows what it is doing with the numbers after that. (I wrote them years ago but they have never taken it down.) The only online calculator I know of right now that is "accurate" in the sense that the mathematical model is correctly implemented is at jt512.dyndns.org/impactcalc.

The pictured broken biner is interesting. A cross-loaded biner will typically blow the gate out but not break the rest of the body. Open and closed-gate failures can break the carabiner spine at the narrow end as occurred here, or nearer to the wide end. I wonder whether the location of the break in tests has to do with different testing protocols. In the closed-gate failure, the wide end is held in place by the gate and gets deformed into a sharper curve by the load until the spine breaks. It is hard to get such loads, even with a grigri and well-used rope. In the open-gate failure, the wide end gets bent down to a shallower curve until the spine breaks---this type of failure is far more likely because the forces required are much lower.

The picture looks like a gate-open failure since the curve of the wide part hasn't been noticeably narrowed. Still, it makes me wonder if the biners were used for sport climbing and if so, if they were gouged by a bolt hanger.
rgold
From Poughkeepsie, NY
Joined Feb 15, 2008
288 points
May 7, 2013
rgold wrote:
The only online calculator I know of right now that is "accurate" in the sense that the mathematical model is correctly implemented is at [[jt512.dyndns.org/impactcalc.


Just to be clear, the above calculator is the same one I linked with the text "JT's Force Calculator" and "JT's Impact Force Calculator". All three of these references lead to the same web page.
Bill Lawry
From New Mexico
Joined Apr 16, 2006
1,604 points
May 7, 2013
were the biners in contacts with a crack? ... its easy to have biners loaded in a crack

as to the "backclip"... with trad draws even if backclipped they are usualy free hanging enough to twist till they are not backclipped when the rope move, or just twist the sling around ... especially the skinny dyneema ones

its much more likely that the gate was facing on the side of the fall and the rope unclipped itself that way

for 3 independent failures to happen .... something must have went really wrong ... or you pissed off the climbing gods with insufficient sacrifice of small household pets
bearbreeder
Joined Mar 1, 2009
1,931 points
May 7, 2013
Russ Walling wrote:
2 hour lead is nothing. On those 6 hour leads I'd put the rope under my head and pull out a few feet of slack. They pull on the rope, it jerks on my head, I wake up and they never see me sleeping. I'd also put a Jumar down the line a few feet from the belay as a third hand... well, the only hand if If I'm sleeping. This was using a Fig. 8 rig or an ATC. .



Haha, I originally was going to say a 3 hour lead but I didn't want to be accused of exaggerating on the internet. I can't even imagine a 6 hour lead, I could drain an Ipod battery watching movies in that kind of time.

I like the rope under the head trick, it could avoid my partner getting mad from having to repeatedly tug on the gri-gri to wake me up.
John D
Joined Nov 24, 2010
21 points
May 7, 2013
First off, glad to hear you guys are OK!!!

And then a couple of comments. :)

If you are looking for things to improve, I'd start with at least this one:

QUOTE: "All of my trad draws are composed of Mammut wire gates for the gear side, Mammut dyneema shoulder slings and the Mammut bent gates."

Why have the wire gates on the gear side of the trad draws? As said several times earlier, wire gates are much less prone to gate flutter (smaller mass on the gate makes it a lot less likely to move do to sudden forces on the biner). Personally, I always have a wire gate on the rope side, where the potential for gate flutter exist.

Here in Europe half ropes are a lot more frequently used also for rock climbing and they really do generate smaller forces on the gear (handy for sketchy winter gear, but maybe also when avoiding breaking biners). Single ropes >10mm usually have a UIAA impact force of >8kN and for <8.5mm half ropes this force is usually <5kN.

Also, I would not dismiss the increase in impact force caused by the grigri as trivial. Check the following from beal (sure there is movement even using a grigri as the belayer is pulled upwards, but still, pretty significant differences):


impact forces for atc vs grigri
impact forces for atc vs grigri


So, would using wire gates in the rope en end of the quick draws, climbing with half ropes and belaying with an atc have prevented the huge whipper? Maybe not, especially if the biners broke due to some twisting forces. But using wire gates and taking various measures to reduce impact forces shouldn't be a bad idea either.

Ps. Still, for two biners to break no matter the above mentioned is amazingly bad luck (one can sure be open due to gate flutter, but TWO?!?), which begs the question of them being somehow weakened beforehand... either by micro-fractures or manufacturing mistakes... both of which again sound amazingly unlikely, when talking about well kept gear from a reliable brand, such as Mammut.
JoelO
Joined May 7, 2013
5 points
May 7, 2013
After reviewing the added picture of the fractured surface, the angle of the fracture, some examples from my "Failure Analysis of Engineering Materials" book, and the BD blog listed above . . . my mildly educated SWAG would be failure due to torsional stress with the gate closed that started at a notch as one person mentioned from clipping to a bolt or other similar damage.

Please take this with a grain of salt as I am only looking at pictures, reading, and reviewing. I did not sleep at a "Holiday Inn Express" last night either, but I was a reliability engineer in a processing plant for a few years and had to make similar analyses. Usually, though, most of my failures were from either chemicals or improper installation/use.
CraigS.
Joined Apr 30, 2012
18 points
May 7, 2013
About the actual failure mechanisms, the thing that seems the most inexplicable to me is that the cam pulled out but the bent gate biner for its sling was missing. Any damage to the cam lobes?

That's a cool graph, Joel. Comparing it to the other reference I mentioned ...

Geir Hundal (see Myth #7), saw forces multiply with the gri-gri by ~1.88 and ~1.14 for FF 0.25 and 0.5. (I suspect the more realistic friction adjustment of Jay T's model explains the smaller multiplication at higher FF but am not sure.)

It appears in the Beal data that the rope with 9.0 kN impact force sees a ~1.34 multiplication of forces which is between the two data points in Geir's test.

And so the two test seem consistent although more detail from both tests is needed to make a complete comparison.
Bill Lawry
From New Mexico
Joined Apr 16, 2006
1,604 points
May 7, 2013
JoelO wrote:
Here in Europe half ropes are a lot more frequently used also for rock climbing and they really do generate smaller forces on the gear (handy for sketchy winter gear, but maybe also when avoiding breaking biners). Single ropes >10mm usually have a UIAA impact force of >8kN and for <8.5mm half ropes this force is usually <5kN.


The impact force ratings for half and single ropes arenīt comparable as the test is different, a dual rated rope like a Sterling Fusion gets 8.5kN as a single strand and 6.4kN as a half rope.
Jim Titt
From Germany
Joined Nov 10, 2009
185 points
May 7, 2013
Cold day at Smug's
Also...this is an aid climb, pretty much nobody is using half ropes for aid climbing. csproul
From Davis, CA
Joined Dec 3, 2009
209 points
May 7, 2013
Not saying everyone should start to use half ropes, especially for aid-climbs, but there is a point in minimizing impact fores and half-ropes is one way to go, even in climbs where you have one or two odd aid pitches, if the rest is free climbing.

But anyway... this is getting on a tangent. I think the important thing here is just to recognize that impact force is a factor to be taken into account when considering the overall safety of one's system, especially on long routes with varying rock and gear quality. And one way to allow more flexibility there (pun not intended!) is to use half ropes (they stretch more and often you can place pieces so that they share the load when coming to a crux).
JoelO
Joined May 7, 2013
5 points
May 7, 2013
" Also--Anthony found the .5 c4 and draw minus the bent gate hung up on one of his aiders by some kind of luck. It was not clipped to it--it was tangled in it and he found it after the fall when he went to set up to jug. So on the way down, we figure his aider hooked the cam and pulled it as well."

You two probably have the best guess as to what happened with this gear. At the same time, I have seen gear pull during a lead fall. It shoots out of the rock and it generally fires off in the direction of the fallen leader. It wouldn't be surprising if the aiders did not snag it and pull it out during the fall but rather - after the piece pulled - acted like a big net that caught the piece with its sling.

Or not.
Bill Lawry
From New Mexico
Joined Apr 16, 2006
1,604 points


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