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The Dangers of Short Static Falls

powhound84

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Feb 24, 2019
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Illinois
I was going to post this in response to an ongoing thread but think it deserves more attention. This is a great read for everyone on this forum just as a reminder of how short falls on static systems can be devastating.


"After witnessing carabiners, slings and daisy chains explode in what I previously considered minor falls..."


Climb Safe: The Dangers of Short Static Falls

By Rock and Ice
May 22nd, 2017

CRACK! The jolt back onto the bolt, into which you are still quickdraw-tethered, stuns you. You only fell two feet, but your neck is stiff and your innards feel like they’ve been kicked by a mule.


climb-safe-137-cover.jpg

Chris McNamara employing proper daisy-chain technique by keeping the sling clipped overhead and using the rope below him to catch a potential fall. Photo by Corey Rich.

Common scenario: You are working a sport route when you clip in directly to your high bolt with a quickdraw attached to your belay loop. Resting on the draw, you suss and brush the holds, then rest some more until you feel strong again. With fresh blood pumping through your forearms—and nary a word to your belayer—you pull back onto the rock, crank a move, and fall.

CRACK!
The jolt back onto the bolt, into which you are still quickdraw-tethered, stuns you. You only fell two feet, but your neck is stiff and your innards feel like they’ve been kicked by a mule. “Lower me,” you say. “I don’t feel so hot. I think my kidneys exploded.”

Another common scenario: You are leading a pitch on a big-wall aid route. It’s dicey, so for extra security you always keep one daisy chain [read: Daisy Chain Dangers] clipped to a lower piece. As you ease onto a high placement, an antique RURP, it pops … and dings you in the forehead, drawing blood. That hurts, but it’s nothing compared to the rude awakening you receive when you drop onto your daisy chain. That impact feels as if it will snap you in two. But just as that begins to happen—SNAP—your daisy chain breaks and you cartwheel 20 feet down the wall until the rope catches you on a lower, bomber cam.

Though you only fell three feet onto your daisy chain, your back is going rigid and your guts are alarmingly astir. There’s also the acorn-sized knot and ooze of blood on your forehead. “Lower me,” you tell your belayer. “I think it’s your lead.”

What happened?
In both situations you fell prey to shock loading, and although your falls were short, both were fall factor 2—the severest possible [read: Fall Factors Explained]. To calculate the fall factor, divide the distance you fell by the amount of rope (or in this case, the length of the draw plus biners) that caught the fall. Fall 50 feet on 100 feet of rope, for example, and the fall factor is 0.5, i.e., not too bad. Fall 100 feet on 50 feet, however, and the fall factor is 2—heinous.

Believe it: Short falls directly onto a quickdraw, sling or daisy chain are more severe in terms of impact forces than any lead fall. In the first example, when you neglected to unclip from that quickdraw, you removed your dynamic rope from the protection chain. Since quickdraws and carabiners don’t stretch, your two-foot fall, rather than gradually being decelerated by the rope, was stopped instantly by the draw. Add to that the fact that you fell two feet on a one-foot quickdraw (fall factor 2), and it’s no wonder you feel like damaged goods.
That impact feels as if it will snap you in two. But just as that begins to happen—SNAP—your daisy chain breaks and you cartwheel 20 feet down the wall.

In the second, aid-climbing example, you did essentially the same thing. Rather than boinging onto the dynamic rope, you shock-loaded the daisy chain, which, unable to stretch, simply blew apart when pushed beyond its load-bearing capacity. And, as in the first example, you cranked off a fall factor 2. Jingus.

Shock loading is among climbing’s most insidious, and potent, hazards. It awaits, lurking, for you to screw up. Shock loading is why, with a lightweight hammer and a short bit of cable, you can funk out welded pins, or break carabiners. Even a small mass moving at high speed and abruptly stopping will generate tremendous energy.

An object going from quickly moving to deathly still may be the hangman’s friend, but it is a climber’s enemy. To ferret out this foe, Rock and Ice conducted a series of drop tests using common items on your rack—quickdraws, runners (nylon and Spectra) and daisy chains—in the aforementioned scenarios. For the quickdraw test, we replicated a fall onto it at its maximum extension (about 12 inches) above the protection. The resulting 24-inch drop sounds tame, but shock loads peaked at 1,600 pounds force, much higher than you’d expect from a mere plop onto a draw. Draw drops from six inches above the pro impacted the anchor with 1,200 pounds of force.

Though the forces from the quickdraw falls didn’t approach the gears’ load limits, they were quite tangible—the crash-test dummy (yours truly) walked away with a sore back—and are high enough to pull or even break marginal gear placements or funky bolts, such as old quarter-inchers or desert spinners.

Wrong! Using the daisy chain as a tether in lieu of the rope can cause bone-jarring falls, gear failure or worse. Illustration by <a target=

Wrong! Using the daisy chain as a tether in lieu of the rope can cause bone-jarring falls, gear failure or worse. Illustration by Jeremy Collins.

For the sling and daisy-chain drops, a 165-pound weight volunteered to take my place. The caveat to comparing “live” drops to “dead-weight” drops is that the human body is gelatinous (some more than others) and has moving parts that absorb energy. A climbing harness also has some load-absorbing capacity. Replacing the body in a harness with a dead weight will increase the forces in any drop test. Nevertheless, this test indicates how equipment, when overloaded, will behave in the real world.

The results of the sling drops were startling. Brand-new, 22-inch-long Spectra (a polyethylene fiber also manufactured under the brand name Dyneema) runners, CE-rated to nearly 5,000 pounds, broke at the end of their 44-inch falls, grim testaments to the forces you can achieve when you fall directly onto a sling. Interestingly, nylon runners, even old, faded ones scrounged off desert towers, subjected to the same test, did not break, although the shock loads surpassed two tons, far beyond the maximum 2,697 pounds force allowed by the UIAA for single ropes.

Attribute the nylon slings’ durability to the material itself. Nylon, even when it is made with a static weave, as with a runner, has some elasticity. Spectra, though it is 15 times stronger than steel, “is as static as static can be,” says Scott Newell, President of Blue Water Ropes, the first manufacturer to market Spectra slings. “Spectra is incredibly strong, but only as long as you apply the load gradually.”

Note that some of the tests were discounted because when the weights fell, the carabiners rotated—causing minor-axis loading—and their gates failed. Such failures reveal the element of chaos caused when rope, sling, carabiners and body fly through space, and only confirm that you should always tie in to the rope instead of clipping in with a carabiner, which can minor-axis load and break. Carabiners that were properly oriented at the beginning can rotate into weaker orientations—pay attention to your carabiners’ minor-axis and gate-open strengths (see wire-gate carabiner chart, page 90), and always use a locking carabiner in situations where proper carabiner orientation is questionable.

The broken Spectra slings, while surprising, aren’t an indictment of the material–not nearly enough sling diameters and lengths were tested to arrive at any firm conclusons. (Look for a more detailed comparison of Spectra, nylon slings and daisy chains in next issue’s installment of Climb Safe.) We do know that Spectra is stronger for its weight than nylon and doesn’t absorb water, a benefit for mountaineering, ice and alpine climbing. The broken slings do graphically illustrate the limitations of a material when it is misused, and show that nylon slings are more forgiving, though they, too, are not designed to absorb energy. Of all the components in the protection chain, only the rope is meant to stretch.

“Using your daisies or slings to catch falls is asking your system to fail, because there is nothing to absorb energy—you have excluded the dynamic abilities of the rope,”The forces generated in the daisy chain drops varied depending on which “pocket” the weight was clipped to. A sewn 54-inch nylon daisy chain with the weight clipped to the chain’s middle pocket (allowing a 54-inch drop) peaked at 2,200 pounds force, at which point the pockets began blowing. Four pockets ultimately ripped before the fall was stopped. Ditto when the weight was clipped to a pocket a third of the way down the daisy. The action of the daisy chain zippering from pocket to pocket slowed the fall dynamically.

When the weight was clipped to the end of the daisy chain, however, and dropped from its full 54-inch extension, both of the daisy chains subjected to this punishment broke cleanly in two. Thus, beware using daisy chains as your primary belay-anchor attachments.

“Using your daisies or slings to catch falls is asking your system to fail, because there is nothing to absorb energy—you have excluded the dynamic abilities of the rope,” says Bill Belcourt, who works in Black Diamond’s equipment-design department. “When the forces get high enough, something has to give. It’s just physics.

But if micro-falls onto static slings, draws and daisy chains are so severe, and climbers routinely misuse gear this way, the question remains: Why haven’t we seen a rash of such accidents?

Right! Using a daisy chain as a keeper cord, letting the rope catch the fall. Illustration by <a target=


Right! Using a daisy chain as a keeper cord, letting the rope catch the fall. Illustration by Jeremy Collins.

Thankfully, the load-absorbing capacity, slight though it may seem, of the human body, harness and other links in the system builds in a fudge factor that somewhat softens shock loading—but don’t count on it. In some cases, shock-load accidents do happen, but are chalked up to other causes. For example, when we fall onto a daisy chain, which shock-loads the placement, which rips, we blame the accident on “pulled pro.” In other cases, the cause is clear. Recently, a climber fell onto and snapped a daisy chain. He then fell farther, breaking his leg. At least two other daisy-chain falls have resulted in ruptured spleens.

Lastly, many of us have simply been dodging a bullet. Time to change our ways. After witnessing carabiners, slings and daisy chains explode in what I previously considered minor falls, I’m rethinking the way I aid-climb: Instead of clipping a daisy chain to a placement and keeping it attached until after I’ve climbed above the piece, I’m going to clip the rope to that piece and unclip the daisy before I climb past it. Then, if I fall, I can ride on down the easy way.

POINTS TO REMEMBER
1.
Quickdraws, slings and daisy chains, for practical purposes, don’t stretch.
2. Any fall directly onto a draw, sling or daisy chain creates a very high fall factor—much higher than if you took the same short fall onto the rope. In some cases, the fall factor is 2, the highest (worst) attainable, and one large enough to have serious repercussions.
3. Keep the dynamic capacity of the rope active in the protection system at all times.
4. When you lead aid pitches, use a system where your daisy chains function as keeper cords only for overhead attachments. Don’t clip them to placements in lieu of the rope, even when the attachment is temporary.
5. Mix up nylon and Spectra slings, using the more dynamic nylon slings whenever there’s a chance you could accidentally fall directly onto an anchor, such as at belays.
6. Use nylon, not Spectra daisy chains, for rock climbing, where the benefits of the non-water-absorbing Spectra are lost.
7. When you rest on a piece connected to your harness via a draw or sling, remember to unclip from the pro before you climb again. Do not work a move while clipped directly to a piece of pro.
 
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Here's a good little eye opener I pulled from that article, for the reading-impaired:

"An object going from quickly moving to deathly still may be the hangman’s friend, but it is a climber’s enemy...For the quickdraw test, we replicated a fall onto it at its maximum extension (about 12 inches) above the protection. The resulting 24-inch drop sounds tame, but shock loads peaked at 1,600 pounds force, much higher than you’d expect from a mere plop onto a draw. Draw drops from six inches above the pro impacted the anchor with 1,200 pounds of force."

Climbing above your tether is no bueno.
 
Several years ago I decided to "test" a HSS vest by stepping off a stand just a few feet off the ground. The total fall was maybe 18"....

If a person could bottle pure violence and unleash it at will falling would rival it. I figured out right then that I want nothing to do with falling for real.

Ever.
 
Several years ago I decided to "test" a HSS vest by stepping off a stand just a few feet off the ground. The total fall was maybe 18"....

If a person could bottle pure violence and unleash it at will falling would rival it. I figured out right then that I want nothing to do with falling for real.

Ever.

Post of the year. People need to read this. Thanks for posting.
 
Here's a good little eye opener I pulled from that article, for the reading-impaired:

"An object going from quickly moving to deathly still may be the hangman’s friend, but it is a climber’s enemy...For the quickdraw test, we replicated a fall onto it at its maximum extension (about 12 inches) above the protection. The resulting 24-inch drop sounds tame, but shock loads peaked at 1,600 pounds force, much higher than you’d expect from a mere plop onto a draw. Draw drops from six inches above the pro impacted the anchor with 1,200 pounds of force."

Climbing above your tether is no bueno.
Thanks for posting , I just roll with whatever you say 3-4 lines from anybody with over a thousand posts should be good enough to build up a setup around & trust my life to......... right. On a serious note I’m scared for people that don’t investigate this stuff for themselves.
 
Love this thread...I’m a risk taker/ corner cutter....as in i’ll “fall” for anything...lol


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Climbing up 15 feet of dynamic 8.5mm rope I have to pull about 2 feet of rope to take out the stretch before I can get off the ground. I know I need two pulls on the ascender. With 9mm static rope the stretch is not noticeable. I like the dynamic for an additional bit of safety.
 
Great post.
I know my amsteel daisy chain tether will be harsh and may fail for an unloaded fall. A fall with slack in my tether. It won’t be good. I don’t think I ever have slack in my tether once I hook in. At least not more than a couple inches. I will definitely pay more attention next time I’m up a tree to see if I put slack and just hadn’t realized it. I’ll link this thread to my post about my tether for more awareness.
 
Good article. I had read it and posted it to another discussion I was on a while back.

People have to realize that these are not fall arrest systems. Like the other man mentioned about stepping off a stand with a HSS system (which is a fall arrest system) and it was still violent as hell.

Yet we still have people that swear the best way to shoot a weak side shot is to stand on your platform facing away from the tree... not the best idea (though I have seen that you can maybe do it with minimal to no slack)

Do things the right way, and keep the slack out of your system!

Do it wrong and well... as they say... play stupid games, win stupid prizes


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Climbing up 15 feet of dynamic 8.5mm rope I have to pull about 2 feet of rope to take out the stretch before I can get off the ground. I know I need two pulls on the ascender. With 9mm static rope the stretch is not noticeable. I like the dynamic for an additional bit of safety.
My 9mm Sterling HTP has a listed elongation of 0.3% at 300 lbs. The dynamic ropes have an elongation of 8% to 11%. Big difference.
 
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et we still have people that swear the best way to shoot a weak side shot is to stand on your platform facing away from the tree... not the best idea (though I have seen that you can maybe do it with minimal to no slack)
That maneuver made me cringe the first time I saw it. Still does.
 
Bump.

This is real issue with all the discussions about ropeman, rope and climbing gear ratings, predator failures, the whole lot of it. Folks are missing the point in all of those arguments. The point I keep trying to make with all of it is simple: If you get into a situation where you're reaching the limits of this gear, on a static anchor, you're asking for trouble. There is a very minimal understanding around here of the math surrounding falls. It's only worse when you get outside of the sphere of a website dedicated to talking about it.

All we can do is continue to bring the stuff up. But it requires being very precise, and not screwing up, or showing bad math. The second you screw up, someone will point out your mistake, and then say "It's all wrong and there's nothing to worry about everything is fine. This idiot doesn't know what he's talking about."

Use "This is my unqualified opinion" if you must talk about things you don't know. Preferably, Don't talk about things you don't know, as fact. Ask questions.

Someone is going to die using this equipment. Let's do our best to keep putting good information out there.
 
I guess this kind of pertains to this but I have a question that I might already know the answer to.
I use the “Kaine method” of climbing with WE stepps but instead of using the strap thing he uses to clip onto the WE steps (then steps up the tree), I use the adjustable aider to clip to the next step. I clip my carabiner for my tether into where your foot goes and adjust it where it’s fairly tight, then grab onto the step above my head, put my foot into the tree and pull myself up. I feel safe doing this and honestly I feel more in control without the lineman’s belt but if I were to fall, would that aider break me in half? Thoughts.
 
I guess this kind of pertains to this but I have a question that I might already know the answer to.
I use the “Kaine method” of climbing with WE stepps but instead of using the strap thing he uses to clip onto the WE steps (then steps up the tree), I use the adjustable aider to clip to the next step. I clip my carabiner for my tether into where your foot goes and adjust it where it’s fairly tight, then grab onto the step above my head, put my foot into the tree and pull myself up. I feel safe doing this and honestly I feel more in control without the lineman’s belt but if I were to fall, would that aider break me in half? Thoughts.

I would not recommend using the steps as your only anchor point. Your tether should connect you directly to the tree, as it’s the least likely element to fail.


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I guess this kind of pertains to this but I have a question that I might already know the answer to.
I use the “Kaine method” of climbing with WE stepps but instead of using the strap thing he uses to clip onto the WE steps (then steps up the tree), I use the adjustable aider to clip to the next step. I clip my carabiner for my tether into where your foot goes and adjust it where it’s fairly tight, then grab onto the step above my head, put my foot into the tree and pull myself up. I feel safe doing this and honestly I feel more in control without the lineman’s belt but if I were to fall, would that aider break me in half? Thoughts.

I can't visualize what you're talking about. But if you're introducing more than a foot or so of slack into a static anchor, you're likely risking a very uncomfortable, if not outright dangerous fall. Pictures or video help
 
I can't visualize what you're talking about. But if you're introducing more than a foot or so of slack into a static anchor, you're likely risking a very uncomfortable, if not outright dangerous fall. Pictures or video help
I'll try to make a video but it's a version of this except I use the aider to clip to the next highest step.
 
Haha like I said, I might already know the answer. I felt like I was gonna fall with a lineman’s belt so I switched to this method.
 
@redsquirrel I highly recommend we sticky this thread. Not only that, also that the text of this article be copied and pasted into a post here, since the link could get broken.

One of the more interesting things I gleaned from this is that dyneema does not take a dynamic shock very well. This applies to all the amsteel bridges that are being used. I may replace my amsteel bridge or at the very least not use it for any method (climbing or shooting) that introduces slack into the system.
 
@redsquirrel I highly recommend we sticky this thread. Not only that, also that the text of this article be copied and pasted into a post here, since the link could get broken.

One of the more interesting things I gleaned from this is that dyneema does not take a dynamic shock very well. This applies to all the amsteel bridges that are being used. I may replace my amsteel bridge or at the very least not use it for any method (climbing or shooting) that introduces slack into the system.

I went ahead and copied over the full content into the original post.
 
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