Monday, October 4, 2010
QC Lab: Dangers of rope worn carabiners
There was an accident a few weeks ago at the Red River Gorge where a climber fell going to the second bolt and the rope was cut completely through by the fixed draw’s sharp-edged, rope-end biner at the first bolt: http://www.redriverclimbing.com/viewtopic.php?f=21&t=13270
If you recall the previous testing and commentary on this subject
(http://www.blackdiamondequipment.com/en-us/journal/climb/qclab/qc-lab-how-sketchy-is-a-ropeworn-sharpedged-carabiner#comment-6599) I had stated that I’d only seen ropes getting “sheathed” by sharp-edged biners—usually mid-route—and subsequently learned of an accident in the Czech Republic (in a climbing gym) where the rope-grooved sharp biner (also at the first bolt) severed the rope completely, resulting in the climber hitting the ground. Luckily in both cases, the climbers were not badly injured.
Which biners get badly grooved and why?
From my experience falling all over routes, all over the county, I’ve noticed three primary locations where fixed biners become badly grooved:
1) First Bolt
• Belayers typically stand too far away from the wall. This results in a sharp angle in the rope from the belayer to the first biner and then up the route. When lowering a climber, the rope, often dirty and gritty, slowly wears a groove in the biner. Both incidents I’ve heard of where the rope was cut completely, it was the first bolt that was the culprit.
2) Crux Bolt
• Many climbers being lowered off the same biner (falling at the crux onto the same bolt). This has the same effect as above. The sharp angle of the rope wrapping around the biner and the weight of the climber being lowered is what is allowing the rope to slowly cut through the biner.
3) Out of line bolts
• Often if the bolt line isn’t straight, an out-of-line biner can end up being grooved. Once again, this is caused by the rope and its angle running over the biner surface.
Testing
We’d done some testing before, but decided to do one more super quick test in our drop tower just to see what it would take to cut a rope on a sharp-edged biner in a harsh, but realistic, loading scenario.
Setup
• Sharp-edged biner (actual biner used in test shown directly above)
• 80 kg mass
• brand new 10.2 mm rope
• One harsh, but realistic, drop
• Static belay
Results
• Rope cut on the FIRST drop (see image below)
• Max load reached - ~7 kN
Discussion
Once again, what does this mean? What does 7 kN actually mean at the piece of protection? What does it mean to you, the gear and the rope?
Well… 7 kN falls can and do happen in the field. These can occur:
• usually when there is not much rope out (i.e., early on in the climb). With not enough rope out, there is little rope to help absorb the energy of the fall.
• and with a close-to-static belay (i.e., belayer hauls in rope and even leans back, trying to keep the climber from hitting the deck.). Loads are decreased with a dynamic belay, but increase with a static belay.
The climber usually “feels” these sorts of falls. Your kidneys take a beating, your hips are sore, and your feet may even hurt from slamming into the wall. I’ve seen many a climber take a harsh fall low on the route—it's usually followed by a deep grunt and “lower me”.
The reality is these sorts of harsh falls low on a route with a sharp biner in play and the rope running over its sharp edge at angle (belayer standing away from the wall) can, and obviously have, resulted in damaging and even cutting the rope.
Bottom Line
Now I don’t want to get into some ethical debate on whether routes should be left with fixed draws or not. The bottom line is you can do a few things to reduce the impact on fixed gear:
• stand close to the wall when belaying, especially when lowering
• use your own first draw on the first bolt of fixed routes
• use long slings to help reduce rope drag
• use steel biners on “high traffic” fixed draws
And of course, it’s in everyone’s best interest to replace worn and tattered fixed gear.
Be careful out there
KP
Tags for this Article:
carabiners, qc-lab, climb, qclab
Photos
Build My Own Feed
United States / English 
23 Oct 2012, 10:56AM
Sad to hear people dying from not inspecting the gear. Surprised no one mentions the use of a pulley on the top rope carabiner. Most pulleys can handle fall loads. impact force should be absorbed by rope stretch and belay device. simple nylon wheel on carabiner very affordable alternative. How about a carabiner with pulley/shiv built into it?
19 Oct 2012, 1:41PM
You could increase the diameter of the quick draws, this will provide a smaller angle between the metal and teh rope, so the rope will have a smaller shear stress
saludos desde MExico
safty first
17 Oct 2012, 3:46PM
Where does one find "fixed draws"? I know I'm in the middle of trad climbing country in the Gunks, but on the sport trips I've made, I've never seen fixed draws. I don't know that I'd trust any of them.
Jay
15 Oct 2012, 1:07PM
I was wondering if a ceramic edge could improve the draws performance. Ceramics are well known for strength and resistance as a material, perhaps a blend with the alluminium could work, but don't know just guessing.
Cheers.
5 Oct 2012, 7:10AM
I-beam shaped biners are especially prone to sharp knife-like edges when they wear down due from rope drag. Light alloy composition biners are worn down more quickly than steel -- meaning that steel is a better choice for fixed biners on routes or at anchors than softer metals.
4 Oct 2012, 4:50PM
For this very reason ClimbTech has come out with a swedged cable draw with steel carabiners. The carabiners have a rounded design to decrease wear as well. We agree with Malcolm, after repeated use, the carabiners will wear down and get sharp just like aluminum will, sometimes sharper. For more check out: http://www.climbtechgear.com/permadraws/
Check all your fixies for sure! Great study guys!
3 Oct 2012, 4:13PM
Great pice of info. Thanks!
But, FIXED quickdraws?? WTF? Use your heads.
3 Oct 2012, 3:12PM
One thing i was wondering is what is the breaking strength of some of those worn biners and if you clipped them to a bolt how thin could they be before the bolt pulled through the aluminum.
1 Oct 2012, 2:12AM
A swiss mountainguide and well known climber died on september 22nd when his rope got chipped as he took a controlled fall in a route with fixed quickdraws. The accident happened in the climbing crag Magletsch in the Rheinvalley in Switzerland. Apparently the biner was worn. Investigations are still pending and I am planning to publish a report when the investigation has been completed in Berg&Setigen magazine. see http://www.mauerlaeufer.ch/index.html
Robert Wallner
18 Jun 2012, 1:51PM
I always follow the wear & inspect rule...Before a climb. Second I always use steel biners.
11 Oct 2011, 2:03PM
Mark —7kN on the climber would be heinous. It was measured on the biner (i.e., last piece of gear).
— Kolin
6 Oct 2011, 3:46AM
Hi. Was the 7kN force measured at the anchor or was that measured at the "climber"?
Mark
16 May 2011, 5:00PM
When top-roping, rigging and fixing biners use STEEL. It does not wear like aluminium does since it is much harder.
27 Jan 2011, 6:49PM
I have two top rope biners that got severely worn after 1 summer of climbing. They were used exclusively on top rope and it was in a very dirty dusty environment. I think my rope just got so dirty that it started wearing on the biners. Once it started cutting there was then aluminum in my rope which i think sped it up... All equipment has been retired now! What did i learn? Wash your rope! :)
24 Oct 2010, 7:29AM
Here's one question not directly related to the above article; recently, I've heard several Austrian guides say that quick-draws should have their gates on the same side. Their argument is that when traversing, the rope-end gate should face away from the direction of movement to reduce chance of unclipping, and the bolt-end gate should also face away from direction of movement to reduce the chance that the gate leans on the bolt in such a way that it unclips itself. However, I'm not really sure if this argument holds. Personally, I think it would be possible to create scenarios where any orientation of carabiners could unclip itself.
So, the question is, true or myth?
cheers,
Tom
22 Oct 2010, 10:09AM
It would be interesting to get some idea of how fast and under what conditions you can get that kind of wear. In training climbing instructors, I see lots of wear on the course gear, though we retire biners long before they get to that stage. It would seem like the only place you would run into the illustrated amount in the field is fixed draws on sport climbs (I have seen it on chains that were used for TR or a lot of lowering, which is advised against - and those chains are steel links, not aluminum - as Mal said, check all "fixies").
Guesses at some factors -
- ropes used in sandy areas without a tarp to keep the sand off the rope (i.e., dependent on the nature of the ground at the climb location)
- ropes not washed periodically, hence collect a lot of grit
- heavily used sport and TR areas, particularly climbs that are test pieces for the area
Any estimates on how long the example biner was in use and rate of use?
18 Oct 2010, 11:49AM
Nice to see some chatter on this topic. To quickly answer a few questions:
The biner used during the experiment was one that I took off a fixed sport route – so it was actually grooved in the field – no machining, etc.
And yes, of course the cross section of the biner has an effect on how much it grooves, and the resultant sharp edge that could form. Some worn biners will have a sharper edge than others, and therefore more potential to cause damage.
Regardless, the whole point is just to be aware of what’s out there and use preventative measures as mentioned above, and to swap out worn gear as necessary.
13 Oct 2010, 3:15PM
Nice work on this - after some rifle cranking, some of the lowering biners were pretty brutal, replaced some with new straight gates.
i like the fixed set up they have - most of the draws are pretty good, and it takes the focus away from the nasty bed frame hangers ...
Cheers, jd
6 Oct 2010, 10:55PM
I've always been weary of "perma-draws" since they seem to be mostly remnants from gear that should have been retired! Perma-draws are necessary on overhung routes and in caves, but it's time to replace the old junk with some modern gear.
There is a steel "perma" quickdraw available for under $15 and at 12Kn it's plenty strong and will far outlast aluminum/nylon quickdraws.
This also reminded me of the crusty old knotted sling with ancient biners on a route we were climbing at Mill Creek this summer. It looked like something one of the original route setters left behind!
5 Oct 2010, 4:36AM
Hi!
How would different carabiner profiles differ in this respect? It seems from your pictures that the effect of wear creates more or less sharp edges depending on the profile.
John
5 Oct 2010, 2:38AM
Thanks for an interesting report! It´s not intuitive that the rope first cuts a groove in the carabiner, and the carabiner then cuts the rope. But it makes sense.
One question remains: how does the design of the fixed piece affect the way it´s worn? It seems to me, from looking at the pictures above, that the profile of the biner makes a difference. Perhaps this would warrant a recommendation as to the type of biner used as fixed gear?
4 Oct 2010, 7:25PM
I just looked at the picture and cross section of the biner in the Red River accident. The cross section of the biner at the point of wear is an I beam shape which leaves an extremely sharp edge when the wear mark approaches the narrowing in the cross section but still has a small amount of the wide bit to go. A biner with a round or oval cross section would not wear to sharp edge like this and so I would recommend not using such I beam biners fixed on routes. Just look at the photo in the link, that is a nasty nasty edge!
4 Oct 2010, 4:28PM
Good article, but one thing that kept coming into my head; If I was climbing on a carabiner THAT worn, I would either stop or replace the biner. It just looks inherently unsafe, and I'm climbing hard the last thing I want to worry about is gear.
4 Oct 2010, 3:10PM
Kolin, as Malcolm says, many draws (fixed or not) develop grooves with use. Usually the grooves are more rounded (or "radiused"); however, they still tend to have a sharp edge, though probably not as sharp as either the carabiner you tested or a fixed-draw carabiner through which the rope runs at a fairly straight angle. It would be good to know how safe these more common round-grooved biners are. Would you be willing to test any, by chance? If so, I can probably send you some biners that have been grooved through heavy use.
Also, for purposes of judging the external validity of the present test, it would be useful to know how the groove in the biner you tested above was formed. Was it through actual use on a fixed draw, or did you cut the groove with a tool, and if so, what sort of tool did you use?
Jay
4 Oct 2010, 8:57AM
Colin, or whomever it was who wrote this report. This is great stuff and thanks for the work. I'll add one thing here and say that worn carabiners at the top or crux draws are usually worn in a radiused profile and are less likely to wear to a sharp edge. First bolt and out-of-line draws, however, are almost alway worn in a manner which leaves one or two sharp edges. Also, don't be lulled into complacency by steel. Sure, it will take longer to wear that aluminum, but it will wear regardless. Check all your "fixies".
Climb
Malcolm