Steel Carabiner Failure to Blame for RI Circus Accident
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Thought climbers might be interested in this: |
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Chinese made I bet. |
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Not sure how reliable the source of this picture is... |
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redundancy anyone? |
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Should have used a Gri Gri. And a PAS. |
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Redundancy was the first thing that came into my mind. I went to an aerial show recently and they only had one biner holding up two people...plenty strong but surprised me none the less. |
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I was about to post this to see if anyone had more info. In regards to that picture above.. I've seen several reports now that described it as a "D" shaped steel carabiner but at this point I'm not really sure if anyone actually knows. Regardless its a sad situation, hopefully more info becomes available about what happens so that no one else makes the same mistake.. |
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"The aerialists suspended by their hair" |
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Local news reports in New England said that the carabiner failed on the non-opening side. So I wonder if it was cross loaded somehow and what that axial strength rating was (they did say 10K as has been posted). |
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The only reason climbers have such an enduring obsession with redundancy is that our gear is made so light that its necessary. |
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Brian Scoggins wrote:The only reason climbers have such an enduring obsession with redundancy is that our gear is made so light that its necessary.That is not true. Our gear is MORE than strong enough that redundancy is not required from a strength point of view. Furthermore most of the time in climbing we aren't using redundancy. Unless of course you are using two ropes, two harnesses, two belay device etc... This "enduring obsession with redundancy" is hardly enduring nor an obsession. The only place where redundancy is consistently used is end of pitch anchors and rap points. |
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I was poking fun at the fact that people will, to this day, question the use of the belay loop, insist on opposed lockers for their connection to an anchor that's right in front of them, back-up enormous trees, etc. etc. |
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Reminds me of the guy who'd organize these big pendlem swings using steel cable on the Florida Key bridges. He got like 8 or 10 to swing with him. Added up their weight... plus a little extra for safety sake, and went out and purchased cable of suitable strength. Two of the swingers bailed before the event, and so they were overall lighter. He neglected to calculate how centrifugal force that magnified their weight. Lucky, the cable snapped near their low point. Impact was sufficient, that one wasn't breathing till the recessitate them on the pick up boat. Broken backs, arms and legs... it was ugly... |
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They probably should have used a shackle for that much weight. Shackles are far more suited for high loads than any form of carabiner. |
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It occurred to me too that shackles might have been a better choice. |
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From the above link: |
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Redundancy is one approach to increase safety in the event of failure. |
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I don't see why it would be so hard to run a second cable an inch or so longer, and have it connected at the same place. Bind both together with some cable clamps and have them run off of different devices at the top. 1 extra motion for the performers, and like $250 for the circus. |
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Redundancy is more for pieces of gear that you don't have complete trust in. You rarely have complete redundancy but it is nice to have as much as possible. |
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patto wrote:Redundancy is one approach to increase safety in the event of failure. When it comes to structural engineering though, the use of redundancy is not commonplace. More common is stringent quality control and understanding of materials used as well as a significant degree of difference between the design load and the design capacity. (AKA safety factor) I would suggest both of these were lacking in this case. A 50kN carabiner does not in my mind provide a sufficient safety factor.Huh? Apparently every known bridge and building code is wrong then. Anything non-redundant is usually fracture critical, and taken heavily into consideration during design. |