Sideloading climbing rings

Discussion in 'Climber's Talk' started by robinia, Oct 30, 2017.

  1. robinia

    robinia Well-Known Member

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    I'm curious to learn if there have been any studies or tests on the use of climbing rings in sideloaded configurations.

    Rings are commonly referred to as 'unidirectional', but of course this only applies to a 360 degree radius along the major axis.

    We are now regularly loading these rings along the minor axis, in effect moving from a 'pull' (proper orientation) to a 'bend' (crossloading).

    Its very likely the forces are negligible given the mostly low, static loads exerted in these applications. But it's worth noting that a onetime well known, hazardous use of gear is now commonplace and excepted(?), at least in these configurations.
    Ie: "Don't ever side load gear. Except these rings, that's totally cool."
    All I'm wondering is where is the testing?

    I side load rings all the time. Redirects, canopy anchors, 3:1 systems, lanyard cinches. It really doesn't seem like a big deal until I start thinking about the potential forces. Spiking a rope like this is completely sideloading: IMG_5836.JPG Maybe even in two different directions ??
    Granted it's a very short length of ring. Virtually no leverage generated. But still worth considering. IMG_5841.JPG

    And what about the biner? Using a biner like this isn't a major axis load anymore. It's something else now. The biner can be oriented along the major axis but it's not seeing that force anymore. Only one end is loaded. Arguably crossloaded. IMG_5838.JPG

    How are these uses any different from the stated warnings?
    (hazards we've been careful to avoid for decades): You_Doodle_2017-10-30T16_41_24Z.jpg

    The difference must be in the linear length of sideloading. Is a 2" section (of ring or biner) that much better than 4" carabiner?

    In this setup both the ring and the biner are (maybe?) side loaded. Each one a good 45-90 degrees off its proper intended use. IMG_5840.JPG


    I'm not condemning here. In fact I'd be very disappointed to have to do without these tricks. To me they're most of the fun of SRT. But even in the likely case that I'm over analyzing here it is important to clearly distinguish what is and isn't 'ok' in the cross loading of gear. People new to the industry may not learn the subtle differences here, or the respective hazards.

    More importantly, where is the literature? Is there any? I can't find any companies showing this as acceptable use?
    (Actually I think the ART snake anchor literature shows a ring used like this)

    Looking for some dialogue here.

    I don't know where the practice came from (mountaineering probably?) but I do recognize that it is fairly new to the arborist world. Maybe learning what industry it originates from would help to track down any available info.


    Another point:
    Often times, depending on the rings, I'll get burrs from the captured biner rubbing against it. Now there is a concern for running rope as well.
    The SMC rings seem especially bad for this.
     
  2. robinia

    robinia Well-Known Member

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    Snake anchor manual: IMG_5850.JPG

    But still, same questions...
     
  3. Brocky

    Brocky Well-Known Member

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    It seems to me that the Snake anchor is more comparable to the x rings than the solid type, because the rope adds to the strength of both.

    Interesting discussion on the possible side loading of both rings and carabiners. It does seem to be a possible misuse.
     
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  4. JeffGu

    JeffGu Well-Known Member

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    In the approved configuration for a ring, the greatest force applied is a stretching of the metal, with a slight bending action once the ring reaches the point where deformation occurs and it approaches the test's prescribed failure point, which could be a certain amount of deformation or breakage. Since it is circular, this is the strongest shape to use when the direction of expected forces form a line passing through the center of the circle, but the angle is unknown (like the hands of a clock, could be any position). Now, if we cut the ring and remove part of it, replacing the missing section with some weaker, movable section/materials for convenience, we essentially have a carabiner and the angle the forces are applied to the circumference become critical. Think of a Petzl Ring Open with a movable gate.

    Ok, now we can easily look at the non-approved configuration for these two items (a solid ring and a ring with a gate) in respect to side loading without having to think about the additional leverage and considerations of an actual carabiner. If we clamped them both into a vise and stuck a pry bar through the center and start wrenching on them, we would generate the forces in the side loading scenario. You would quickly find that the solid ring has little trouble resisting these forces compared to the gated ring, to the extent that we probably wouldn't even consider using the gated one for the purposes you're talking about. The Petzl ring has a quite strong, semi-permanent gated section, so it might fall somewhere between our two examples. Probably closer to the solid ring than the other, but there would still be some weakening of the ring.

    Now, we're back to just considering solid rings. Between aluminum and steel, you'd very quickly figure out that even with a 3-foot pry bar, you aren't going to bring either one into failure mode easily. But, you'll also discover that the steel has horrendously better resistance to these forces than the aluminum, regardless of the ratings stamped on them. Those ratings only give you a clue about their ability to resist the forces in the approved configuration. I'll save you some work, and tell you that you are not going to tweak the steel ring enough to make it wobble when layed flat on a glass table. The aluminum one, you will be able to do this. I was never able to deform a good steel ring this way, myself, because anything I could use for a pry bar that had a chance of doing this simply wouldn't fit through the ring.

    This was a terribly long winded way to tell you that I seriously doubt if you need to worry one bit about sideloading a steel ring (I do it every time I'm in a tree with both climbing and rigging scenarios) but an aluminum one might be an issue... I simply haven't bothered to try to determine what forces are required to deform them to a dangerous point. I did try to deform a big steel ring (4" OD, 3" ID) with a 1" steel bar for the ring to bend around and some quite heavy chain, shackles, and a pickup truck. The damn chain broke without bending the ring, so I decided that side loading those things was a lot less of an issue than I thought anyone needed to worry about. These were not entirely static attempts, either. I was jerking the truck back and forth a bit when the chain broke.

    I'd love to see a similar test with a bit more science and engineering in the design. I'm not sure the results would be terribly enlightening, though. I think the steel rings are lots tougher than we think, and I suspect the aluminum ones are not as wimpy as they feel in your hand.
     
  5. Tom Dunlap

    Tom Dunlap Longest registered member

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    This would be a good question to bring along to Expo to ask the various Metal Magicians who make rings and biners. I know that I've had questions for them in past years that were answered by short and long answers

    Most of the time the short answer has been enough to satisfy my curiosity. Simply...Don't worry

    Then, the long answer gets into engineering lingo where I get lost
     
  6. DSMc

    DSMc Well-Known Member

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    It seems that a simple test could be done with a truck to determine the failer point of each configuration. My guess is that the rope will fail well before the rings.
     
  7. ghostice

    ghostice Active Member

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    I guess to throw in my two cents, I've wondered the same kind of things, silently. The DMM rings as an example, come in different sizes and so do ropes of course. I tend to stick with DMM Ultra-O's for choking configurations (a la Lawrence S . . . ) but I have wondered about ring sizes, which can sort of load things differently (in my mind anyway not being a mechanical engineering type) - the biner goes a lot farther in with a larger ring size. And some ring sizes get pretty large (like the black ring that came with the Monkey Beaver Harness - not sure what brand/ size it was). So is a smaller ring better as a general rule? And with what size rope? And steel v.s. aluminum (and what alloy, because they are different MBS). All good questions I'd like to see explored more too. Are there also any issues concerning the bend radius of the ropes used and influence of carabiner profile - i.e. round v.s. "I" profile.
     
    Last edited: Oct 31, 2017
  8. robinia

    robinia Well-Known Member

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    Another reason I wish I was going!!
    Argh.

    We'll cross paths someday Tom.
     
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  9. robinia

    robinia Well-Known Member

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    Oh for sure.
    I guess a big part of my questioning is because this directly goes against what we've always been taught.
    It's partly a principle thing.
     
  10. robinia

    robinia Well-Known Member

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    I use the different ring sizes totally based on function. I've found a large ring just doesn't hold tension when spiked the same way a small one does.
    Strength wise it's probably not that different, although theoretically the smaller one is receiving less cross loading.
    I'm almost always using a large steel ring for canopy anchors. 70kn compared to 25kn?
    The only reason to use aluminum is heat dissipation and weight, right? So in a canopy anchor those things just aren't real considerations.
     
  11. robinia

    robinia Well-Known Member

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    That's a really great explanation. Lots of good info so thanks for that.
    You mention approved and non approved. That's really the root of the issue. Especially when so many of the common uses for us fall into 'non approved' status (redirects, canopy anchors, etc)
    It's this gray area that I'm curious about, particularly in the case of an accident, or more likely in training others. When is 'non approved' ok?
    So many times I've had people try to tell me that they use rings like this because they can be loaded in 'any direction'. Which is not accurate.
    And honestly it's newer climbers I'm hearing saying that.
    Clearly there is a good deal of misinformation about this.
     
  12. JeffGu

    JeffGu Well-Known Member

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    Yeah, they can be loaded in any direction when the lines of force pass through the center and a point on the circumference, but otherwise you end up trying to fold the thing in half and that's not how it was intended to be used. However, the steel ones are pretty hard to break, even doing that. The aluminum ones I'm not so sure about, although I do use them like that, too, on redirects. On choked canopy anchors that use rings, I always use the steel ones. They also can handle a lot more physical abuse from banging around against other objects, including themselves. You can beat on one of each with a hammer, and really see the difference. It's very easy to make the aluminum one look unsafe to use, but the steel ones you'd be lucky to do any damage that wasn't of a superficial, cosmetic nature.

    I started getting used to the aluminum ones on the redirects because they're so much lighter, and the steel ones tend to hurt if they come back down the rope at high speed on retrieval. I still set them on a hard, flat surface every now and then... the first time I feel one deformed enough to wobble, I'll go back to the steel ones. It hasn't happened, yet, but I'm only just starting to use those redirect techniques.

    I'd really like to know just how much force it would take, side loading an aluminum one, to make it fail. I suspect it might be enough that these uses would be ok to trust, but I really don't know. The steel ones I think would be stronger than the rope no matter how you load them. The ones I use are just silly strong.
     
  13. DSMc

    DSMc Well-Known Member

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    It will be interesting what you can find out about this. It seems almost inconceivable that a DMM ring could fail at anything close to its WLL of 6kn, regardless of how the load was applied.
     
  14. Tony

    Tony Well-Known Member

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    DSMc,

    You are correct, but how the different configurations load and where the rope fails is intresting.

    Et al,
    Lucas Drews and I will be looking at some rcent tests duruing our talk Friday morning discussing some of these very concepts. (Yes that is a shamless plug)

    Tony
     
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  15. robinia

    robinia Well-Known Member

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    Shoot! Wish I could see that!
    Will this info be available elsewhere?
     
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  16. Tony

    Tony Well-Known Member

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    Not sure. I’ll use it in my climbing classes and may present it at other events.

    Tony
     
  17. colb

    colb Well-Known Member

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    Seems like TreeStuff could test this on their tester mctesty....
     
  18. DSMc

    DSMc Well-Known Member

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    Aaaah...... Saftey secrets.
     
  19. Tony

    Tony Well-Known Member

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    No, nothing like that. We (Lucas and I) have just prepared the material as an accompaniment to a presentation, not a stand alone entity. The vids, charts, graphs, pictures with lines and circles and a number on the back require context.

    As with all TCI Expo talks there will be an accompanying article, but for a 2 hr 15min presentation it will be truncated by necessity of 1500 or so publication word limits.

    The plan is to present the material a few times at various venues (trade shows, open enrollment courses, private courses, chapter events, etc.), allow that process to further refine it, add to current data with further testing, then, next spring publish somehow in various media.

    If we found glaring misconfigurations and/or major safety issues, I would spread the word far, wide and quickly. The “numbers” as alluded to break the rope, before hardware (unless something monumentaly stupid is done). However, well before the rope fails, the body would succumb!

    The idea is to glean insight into the forces, how they mesh with the tree and climber to develop some best practices. I am not a scientist (not even on TV) and would never refer to what we generated as “proven fact.” This is a process we started a few months ago and will continue with. The TCI expo is just one preliminary step.

    We have yet to “test” many of the configurations pictured in the post. We began with canopy anchors and basal anchors-suspension points.

    Tony
     
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  20. DSMc

    DSMc Well-Known Member

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    Thanks for the clarification, Tony. I had assumed if a safety concern had developed on the integrity of rings, that you were aware of, you would have just said so. But that is not what was stated.

    I'm glad that you and Lucas are researching and presenting on this subject, it is needed. Hope it goes well at expo.
     
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