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Gear Failure on West Face Leaning Tower results in whipper.

Rob Dillon · · Unknown Hometown · Joined Mar 2002 · Points: 760

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.

sherb · · Unknown Hometown · Joined Dec 2012 · Points: 60

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

Bill Lawry · · Albuquerque, NM · Joined Apr 2006 · Points: 1,812
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.
rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526
Caprinae monkey wrote: There is a site you can check what kN force the falling climber generated: myoan.net/climbart/climbfor…
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.
Bill Lawry · · Albuquerque, NM · Joined Apr 2006 · Points: 1,812
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.
bearbreeder · · Unknown Hometown · Joined Mar 2009 · Points: 3,065

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

John D · · Unknown Hometown · Joined Nov 2010 · Points: 10
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.
JoelO · · Unknown Hometown · Joined May 2013 · Points: 5

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

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.

CraigS. · · Unknown Hometown · Joined Apr 2012 · Points: 10

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.

Bill Lawry · · Albuquerque, NM · Joined Apr 2006 · Points: 1,812

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.

Jim Titt · · Germany · Joined Nov 2009 · Points: 490
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 aren´t 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.
csproul · · Pittsboro...sort of, NC · Joined Dec 2009 · Points: 330

Also...this is an aid climb, pretty much nobody is using half ropes for aid climbing.

JoelO · · Unknown Hometown · Joined May 2013 · Points: 5

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).

Bill Lawry · · Albuquerque, NM · Joined Apr 2006 · Points: 1,812

" 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.

Tabo · · Unknown Hometown · Joined Aug 2006 · Points: 20

Hopefully someone checks this ... Using * Jay T's Impact Force Calculator
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.

These are the two threads that went into creation of the calculators. Look for posts between QTM and JT.

Quick discussion about the calc
rockclimbing.com/cgi-bin/fo…

Original thread.
rockclimbing.com/cgi-bin/fo…

Will S · · Joshua Tree · Joined Nov 2006 · Points: 1,061

Torsional forces? On a rope-end biner that is floating in a sewn sling, not straight into a hanger? Just not seeing the mechanism there for any real torsion without the biner somehow being pinned.

Seems a little curious that 9/10 biner breaking stories I've read were all Mammut biners. Those Moses superlight wiregates were blowing up left and right a few years ago.

I'd chalk the whole deal up to freaky anomaly...but I also wouldn't be climbing on Mammut biners anytime soon either.

Travis Haussener · · Unknown Hometown · Joined May 2012 · Points: 60

I'm saying a little Occam's razor mixed with Murphy's law...what could of went wrong did go wrong, and why?...really bad luck. You guys should have doubled down on black that day instead. The good news...a situation like this probably won't happen again for at least 30-40 years so we're all in the clear thanks for getting it out of the way for everyone else. Kind of like two commercial jets haven't crashed in the same week, month, year or whatever.

Glad you guys are ok. Did anyone go up and check the integrity of the bolts afterward. I know they're rated to elephant strength but given the string of events who knows?

Optimistic · · New Paltz · Joined Aug 2007 · Points: 450

Were there any batch numbers visible on the failed biners?

slim · · Unknown Hometown · Joined Dec 2004 · Points: 1,103

agree with willS, not seeing what will act as a reaction force to the torsion, as a sling has very little torsional stiffness.

also, interesting point about the mammut biners. that was my first thought also - seems like a LOT of broken biner reports i have read were mammuts, particularly moses, which unfortunately i have a bunch of....

sherb · · Unknown Hometown · Joined Dec 2012 · Points: 60

Ah yes sorry about the bogus falling force calculator... I didn't know it was messed up. But it's crazy yet good that they would have the FF messed up (I think this crossed my mind but figured who would create a faulty calculator), if they didn't, it would be difficult to verify the kN force is also unreliable.

So many factors go into a real life situation. I have an engineering degree but when my classmate totaled his Corvette, we tried to calculate how fast he was going, or the friction of the road surface, or something, and the number came out to be completely unrealistic. So it was then we realized that the physics equations (sometimes you learn the simplified equations only to learn there are additional parts of the equation, e.g. E=mc^2 is only part of it, and the other parts "cancel" in a particular situation) often don't apply to real life where there are so many other factors involved.

Guideline #1: Don't be a jerk.

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