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Two Opposite and Opposed Carabiners: Possibly Weaker Than a Single Carabiner
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By Tom Mulholland
From #1 Cheese Producing State!
Nov 12, 2013
Whiskey-a-Go-Go

I am honestly surprised, although I probably shouldn't be, by the outright dismissal of the value of these tests. Doak brings up some good points about scenarios where the loads really could be significantly high. And, although I'll take it as granted that there are no reported top rope carabiner failure accidents, there are plenty of examples of equipment failure, often due to failure to understand the limitations of the same.

I can think of 2 deaths/injuries off the top of my head relating to carabiner failure that surprised me, just in the last few years, albeit other might have understood these risks beforehand. I believe both were in the Red River Gorge: a rope getting cut by a worn, sharpened aluminum carabiner, and a carabiner breaking when somebody fell while clipped directly to a bolt with a quickdraw.

If new research leads to new understanding of the equipment we entrust with our lives, and prevents an accident someday, I fully support it. Hell, I support it just because it's interesting. Thanks, 20kN, for always posting these and your own results.


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By Pete Spri
Nov 12, 2013

From that video:
1. you cannot tell what biners are used.
2. you cannot tell how they are configured.
3. you cannot see the set up of the sling; it appears to be girth hitched on itself
4. you cannot see if the sling is tubular or what material it is made of
5. there are no numbers for failure rate of the biners or the sling.

Overall, no information to even discuss this, unless there is somewhere that the OP is getting these numbers from and pictures for configuration and materials used. WTB link please.


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By slim
Administrator
Nov 12, 2013
tomato, tomotto, kill mike amato.

Don Ferris wrote:
He's not saying a TR fall will generate these kinds of loads (26kn). He is pointing out that with two steal lockers rated at 50 kn a piece, because of the opposite and opposed setup, failed at around half of what they were rated. So, if all things remained the same except with aluminum lockers rated at 24kn a piece, it is feasible that they might fail at 12-13 kn which in some rare scenarios is possible to generate in a climbing fall.


am i the only person that found it ironic that don ferrous mis-spelled steel?


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By bearbreeder
Nov 12, 2013

The cutting of ropes over sharp edges and biners have been known for many years ... Ill post up the DAV articles when im back on a real computer

As has poor loading of single carabiners ... The petzl documentation warms explicitely about it i believe as has the BD qc lab

blackdiamondequipment.com/en/qc-lab-weakness-of-nosehooked-c>>>

This is common sense .... Odd carabiner loading and sharp edged are dangerous

This is taught to new climbers in courses (or damn well should be if youre a credible "teacher") all the time

As others have expressed the danger is NOT both biners breaking in a TR/lowering situation ... It is in the gate coming open and the rope coming out ... This is what opposed biners prevent

Again if you can show an accident where 2 opposed biners both failed in a climbing situation there a reward ... I believe it even extends to "realistic" tests

www.rockclimbing.com/cgi-bin/forum/gforum.cgi?post=2565680

By all means test it ...

But we are not pull test machines, and realistically if you are worried about the strength of 2 opposed biners, ive got a whole list of things you should stop using

Ive said it before ... People will argue about this and every other minor "safety" issue on the intrawebs ... And ive seen newbies at the crags shouting it out loud ...

Its not whats going to kill you

I find it amazing how so many can argue about deadly opposed biners, gridlocks, deadly dyneema, etc ... And how they want to be "safer"

Yet not take the most basic precaution against a known killer ... A helmet

;)


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By Bryan Hall
From Bend, Oregon
Nov 12, 2013

Are there any documented instances of real world situations where toprope carabiners fail when set up correctly?

I've attached a photo of the worst top rope setup I've ever seen. The climbers were dogging all over this and I obviously don't recommend it but was impressed that the carabiner that was actually taking the load didn't snap.

Once notified of my concerns about their setup they let me fix it right away.


Poor form on a top rope setup.
Poor form on a top rope setup.



As an additional note: I think this kind of thing happens when people don't learn anchor building, but simply think they can quick two quickdraws to bolts and call it done no matter what. This setup happened in the lower gorge of smith rock in an area where the bolts are on top of the cliff band instead of on the face.


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By Woodchuck ATC
Nov 12, 2013
Rock Wars, RRG, 2008

When I use 2 biners for my masterpoint, I use one locker and one non locking. They must be of nearly or identical design and shape, and I do not reverse the gates since one locking carabiner is sufficient for any 'accidental' unclip. Mixed gate and shapes or sides up or down can add twist or stress to the rope running through the carabiners, thus I do not switch them around. Works fine, accident free top rope anchoring system for me the last 35 plus years.


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By NC Rock Climber
From The Oven, AKA Phoenix
Nov 12, 2013
tanuki

Bryan Hall wrote:
Are there any documented instances of real world situations where toprope carabiners fail when set up correctly? I've attached a photo of the worst top rope setup I've ever seen. The climbers were dogging all over this and I obviously don't recommend it but was impressed that the carabiner that was actually taking the load didn't snap. Once notified of my concerns about their setup they let me fix it right away. As an additional note: I think this kind of thing happens when people don't learn anchor building, but simply think they can quick two quickdraws to bolts and call it done no matter what. This setup happened in the lower gorge of smith rock in an area where the bolts are on top of the cliff band instead of on the face.


That TR anchor is setup incorrectly. The issue is not two opposite and opposing carabiners, but way that the anchor is constructed.


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By Bryan Hall
From Bend, Oregon
Nov 12, 2013

NC Rock Climber wrote:
That TR anchor is setup incorrectly. The issue is not two opposite and opposing carabiners, but way that the anchor is constructed.


Yep, I know that and stated it when I posted it. I used it as an example to show that even in what I would consider a worst case scenario the carabiners still didn't break. This setup seems far worst than this theoretical opposite and opposed problem since this is a single carabiner folded over the edge of the cliff.

My question was is there any instances of top rope carabiners failing when they are set up correctly?


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By NC Rock Climber
From The Oven, AKA Phoenix
Nov 12, 2013
tanuki

Bryan Hall wrote:
Yep, I know that and stated it when I posted it. I used it as an example to show that even in what I would consider a worst case scenario the carabiners still didn't break. This setup seems far worst than this theoretical opposite and opposed problem since this is a single carabiner folded over the edge of the cliff. My question was is there any instances of top rope carabiners failing when they are set up correctly?


You did state that. I should have done more than just skim your post.

I don't think that there is an instance of biners failing when set up correctly. Others might have proof otherwise.

I think that your point regarding them not failing just shows how hard it is to break this stuff in a TR situation. I am not saying that biners don't break or that proper alignment is not important. I am saying that there are a lot of bad / marginal anchors out there and that we seldom (ever?) hear about carabiners breaking in tr anchors.


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By Bryan Hall
From Bend, Oregon
Nov 12, 2013

NC Rock Climber wrote:
You did state that. I should have done more than just skim your post. I don't think that there is an instance of biners failing when set up correctly. Others might have proof otherwise. I think that your point regarding them not failing just shows how hard it is to break this stuff in a TR situation. I am not saying that biners don't break or that proper alignment is not important. I am saying that there are a lot of bad / marginal anchors out there and that we seldom (ever?) hear about carabiners breaking in tr anchors.


Agreed.


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By rocknice2
From Montreal, Quebec
Nov 12, 2013
BD ice tool fusion2

Bryan Hall wrote:
Are there any documented instances of real world situations where toprope carabiners fail when set up correctly? I've attached a photo of the worst top rope setup I've ever seen. The climbers were dogging all over this and I obviously don't recommend it but was impressed that the carabiner that was actually taking the load didn't snap. Once notified of my concerns about their setup they let me fix it right away. As an additional note: I think this kind of thing happens when people don't learn anchor building, but simply think they can quick two quickdraws to bolts and call it done no matter what. This setup happened in the lower gorge of smith rock in an area where the bolts are on top of the cliff band instead of on the face.


From the picture you posted above, the QD's may have been and most likely were properly installed. The topropers were probably flailing about and spinning around the rope. This caused the anchor to twist around.


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By Ray Pinpillage
From West Egg
Nov 12, 2013
Cleo's Needle

This is why I only top rope with 7 HMS biners.


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By rogerbenton
Nov 12, 2013
Whoever this guy is, he's just plain irresponsible.

that pic of the fuhklempt tr anchor looks to show rappel wear on the one quickdraw biner...
makes the anchor situation none too surprising.


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By Bryan Hall
From Bend, Oregon
Nov 13, 2013

rocknice2 wrote:
From the picture you posted above, the QD's may have been and most likely were properly installed. The topropers were probably flailing about and spinning around the rope. This caused the anchor to twist around.


I seriously doubt that. I have never in 8 years of climbing and guiding seen climbers flail on a top rope in such a way that the quickdraws move upwards, twist over each other and then settle onto an edge. Everything I know about physics, climbing, rope and anchor systems defies the possibility that the top rope caused a correctly set up anchor to do that.


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By David Coley
From UK
Nov 14, 2013

20 kN wrote:
I might try to pull test some AL non-lockers O&O to see if I can replicate the results of his testing. If two locking steel carabiners are failing at loads that low, I am curious what would happen with the ever-common double non-locking aluminum biner O&O configuration.


As someone who has had a powerpoint screwgate snap on him, often uses back-to-back snap gates rather lockers, uses two lockers to attach his silent partner and who sometimes leads using a pair of lockers rather than by tying into the rope, I would be very, very, interested in any results you come up with! Thanks.


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By patto
Nov 15, 2013

So many people here have missed the point....


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By Old and Busted
From Centennial, CO
Nov 15, 2013
Stabby

nicelegs wrote:
These threads don't teach us anything about rock climbing. What they teach us about other climbers is a wonderful thing.

These threads are like asking a woman if there is another woman at work she doesn't like.


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By rocknice2
From Montreal, Quebec
Nov 15, 2013
BD ice tool fusion2

Bryan Hall wrote:
I seriously doubt that. I have never in 8 years of climbing and guiding seen climbers flail on a top rope in such a way that the quickdraws move upwards, twist over each other and then settle onto an edge. Everything I know about physics, climbing, rope and anchor systems defies the possibility that the top rope caused a correctly set up anchor to do that.


Don't be so quick to doubt. If the climber spins up and over the belay side of the TR, this can cause havoc upstairs at the anchor. Especially if it's 2 QD's.


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By John Wilder
From Las Vegas, NV
Nov 15, 2013

rocknice2 wrote:
Don't be so quick to doubt. If the climber spins up and over the belay side of the TR, this can cause havoc upstairs at the anchor. Especially if it's 2 QD's.


mmmmm....i dont think so. if they spun over and around a few times, maybe- but just being over shouldn't do anything to the anchor. and in my head, i cant imagine the anchor doing anything under tension, especially if its laying flat on the rock under load.

i suppose if the climber spun around the rope several times then unweighted and the anchor was free-hanging....maybe?

that said, that pic looks like they probably set it up from above then drug the anchor across the edge- forcing a twist when the draw caught. that particular anchor spot wouldn't be my top choice for a pair of draws.


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By rocknice2
From Montreal, Quebec
Nov 15, 2013
BD ice tool fusion2

It's most likely a combination of things. Twist in the toprope, climber tried the adjacent route, there was a ledge along the route..... You get the idea. It's not that inconceivable to reproduce the picture above.

If someone is going to flail then a single master point with 2 locking biners is a good idea.


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By Rockbanned
From Plattsburgh, Ny
Nov 17, 2013
Slab...

the rope is still the weakest, and NON-redundant link in the scenario. Wth? All this redundancy with a single point of failure, "the rope". Silly


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By Locker
From Yucca Valley, CA
Nov 17, 2013
...

"it is possible to cause two 50kN-rated steel carabiners to fail as low as 24kN when loaded as a single unit"


Oh my god! Only 24kn? No way that's strong enough.


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By Pete Spri
Nov 17, 2013

I see the concerns that it raises. If two steel biners fail at half of a single ones rated value, then for aluminum it could be even worse.


My problem with this is the validity of the test. I wish 20KN would have posted the "study". All he posted was a video, and you cant tell much by that. If anything, it actually looks to me like the sling was girth hitched in the video, creating a pulley effect on the biners that would actually probably come close to accounting for the compounded force on the biners, explaining the "1/2" strength loss.

But it's all conjecture until you get actual facts for the "study".


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By rgold
From Poughkeepsie, NY
Nov 17, 2013
The traverse out to the Yellow Ridge on the Dogstick Ridge link-up.  Photo by Myriam Bouchard

Relevance to any real-world concerns aside, there seem to be some issues of vocabulary.

The 50 kN rating on the steel biners is presumably the level at which they break under load. These biners did not, as far as I can tell, break (the video is completely worthless in terms of understanding what happened to the biners). The gates apparently broke from the sideways loads imposed by the locking collars. That sideways load rating, if one exists, would be a completely different rating, not the 50 kN rating, and presumably much lower than 50 kN, so comparing the results to the 50 kN rating is sensational but misleading.

If one wanted a comparison with the 50 kN rating, the test should have continued until both carabiners broke and released the yellow sling. As it is, it appears that the gates have broken but the "climber" is still belayed on a pair of reversed links, albeit both open. Scary, but no fatalities, even of the virtual kind, yet. Meanwhile, the plausible assumption that you get double the gate-open rating of a single biner is untested.

So for example, if you get bust two BD Positron lockers this way, with a gate-open strength of 8 kN, your damaged system might still be able to withstand 16 kN or so before breaking.

As for methodology, there may be a difference between having a relatively narrow climbing rope provide the load and the relatively wide yellow sling used in the test. The narrower climbing rope profile is much more likely to allow the carabiners to rotate outwards, aligning their spines as the load is applied, so that the gates no longer press against the spines of the opposite biner, as in the picture posted by Joshua Reinig of the reversed D-shaped biners.


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By 20 kN
From Hawaii
Nov 17, 2013

David Coley wrote:
As someone who has had a powerpoint screwgate snap on him, often uses back-to-back snap gates rather lockers, uses two lockers to attach his silent partner and who sometimes leads using a pair of lockers rather than by tying into the rope, I would be very, very, interested in any results you come up with! Thanks.

I actually tried to replicate the results using two oval solid-gate non-lockers, and I couldent break the gates. I'll try with some lockers. What is a snap gate?


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