Carabiners Break?!?!?

(I had to change the title to get your attention... If you have any thoughts, please contribute!)

Hello MP community,

I wanted to get in touch with you all to see what sort of statistical studies related to rock and ice climbing you all would like to see performed.

Examples of notable previous topics:
-Nylon vs. dyneema breaking strength
http://dmmclimbing.com/knowledge/how-to-break-nylon-dyneema-slings/

-Ice screw pull strength
http://video.google.com/videoplay?docid=1863958284744514965

-Carabiner major, minor, and open axis pull testing
youtube.com/watch?v=ZyVD0FB…]] youtube.com/watch?v=ZyVD0FBLiF
and so on and so forth.

As an adventure education major at Fort Lewis College I am required to conduct a statistically observable research and design project. I'd like to hear from the climbing community to see what, if anything they are curious about.

I understand that a study similar to my own hypothetical one has likely already been conducted, but for the purpose of understanding the process of professional level research and design, any help is much appreciated.

Some ideas I've had:
-Pull testing of ice screws left in the sun at 15 minute intervals
-frozen knot/ wet ropes/ dry treated/ non-dry strength reduction scenarios
-notched carabiner (as in worn perma draw 'biners) pull testing
-???

Let me know what YOU want to know, and please offer any suggestions you might have about conducting the experimentation phase.

Cheers!
-Dylan Weldin

dylan-

for anyone who buys used cams or ties into tat anchors of unknown age:

could you devise a way to pull test slings with different levels of sun exposure?

it seems like the timeline and less than controllable levels of exposure would be a pain in the ass to cope with but it would be interesting and valuable to see at what point in hourly sun exposure slings start to show strength degrade.

good luck with your project.

A fall on a pin and a cam in a wet sandstone vs dry. Belay loop strength test after some wear on it or exposure to sun, wet.

I watched the video of slowly increasing force, what about dynamically pull testing a carabiner?

Roger- Good Idea but it would seem hard to conduct such a test on any sort of schedule. I have been rapping off of slings in S. AZ that have been out in the desert sun for a year or more.

A lot of the stuff mentioned has been done by BD or DMM or one of the other major brands. Doing tests that involve dynamic ropes are hard too because the dynamics of the rope change with every fall, and giving a dynamic belay is hard to simulate.

The most accidents happen on rappel, so why not put some effort into rappels? here are a couple thoughts:

determine the amount of braking force you need to stop your self. You can do this on different parts of the rope (top of a rappel where rope weight helps you, middle of the rope, bottom of the rope). Single vs. double rope rappels. different rope diameters (twins, doubles, skinny - medium - fat singles)

you could also look at extended vs non extended rappels.

backup knots are cool too. Which one workes best? prussik, autoblock, kliemheist?

just a few thoughts, there is plenty more you could do with the topic.

Dylan Weldin wrote: I understand that a study similar to my own hypothetical one has likely already been conducted, but for the purpose of understanding the process of professional level research and design, any help is much appreciated. ... Cheers! -Dylan Weldin

There are many such testing ideas and papers written. A good resource is checking out the ITRS online to see some of the various ideas presented. Most of which are indeed backyard and garage tests, some with small sample sizes, some with more than adequate data collection & discussion -- still, this is all just a relative 'newborn infant' in the age of science. So don't let previous work dissuade the idea of taking any concept and testing the hell out of it.

Maybe the most underestimated problems in system integrity are the shortcomings of the carabiner and breaking devices over many types of applications that a climbing team might see out in the environment. Another is mass composition in static or low stretch situations, not entirely typical of climbers because of dynamic materials and the human body, but human testing requires protocol control.

Just to second what Jake said, it would be great to see some stats on gear placed in actual rock and part of a real climbing system

Living where we live, I would like to see some sandstone tests. Something along the lines of what BigJuggsjohnson said. How good are the bolts in sandstone after a rain? Can I go TR at XRock as soon as it's dry? What about leading up at East A?

Jake Jones wrote: I agree. I think this would be one of the key reasons to do a test like this- to determine how much dynamic property is lost between falls in close succession. Not really. I think if you were on overhanging terrain, an 80kg mass on the sharp end, and a 65kg mass on the belay end would simulate it pretty well- give or take a few kgs.

Using a weight doesn´t simulate the effects of a normal belay device in drop-tests, not in any way or form. The inertia is the problem.

I would be interested to know how caribiners and belay devices strength vary as they are heated.

For instance if you took multiple whippers on the same biner, and heat built up in the device.

In a caving situation, long ago, I would rap down a 300' rope using figure 8, and by the time I'd get to the bottom the eight would be hot enough to give a severe burn if touched with bare skin. Now days, I use a rack with steel bars, understanding the danger of cooking through the rope.

I'll cast a vote for the sandstone test. Go to you tube and search for 'don't show this to your mother'. I believe this incident was attributed to wet sandstone.

The force a belayer standing on the ground (or better anchored) will apply on the end of the rope is a function of rope diameter, hand strength and belay device, somewhere around the 2kN to 4kN level is normal and it is fairly constant over the braking cycle (but not completely).
The force a weight applies to the rope is a function of the weight and acceleration and the acceleration is dependent on how fast the climber is falling and their weight, since the faller is slowing down the speed varies throughout the fall/stop cycle and therefore the force.

For this reason one uses an artificial hand to control the rope through a belay device which applies a constant force onto the belaying rope, there are a couple of designs used either using steel discs pressed together or a rotating drum where the torque can be controlled. this is the only accurate way to consistantly reproduce falls involving belay dynamics in a way that can be repeated and accurately varied (and measured). There is one available in Italy and one in Germany but not in the USA as far as I know.

No problem. There are work-arounds for rappelling and belay plate tests themselves, some of which are fairly simple and others which are cumbersome to say the least. We designed a huge winch for controlled abseiling tests over complete rope lengths and even got most of the bits together but this is waiting for a rainy day to get put together!

For the OP. Just about everything engineering wise has been studied, even if the results aren´t readily available as they are commercial projects. More in the line of education an interesting thing to study is how well people can equalise belays (or judge the equalisation). This has been studied to a certain extent but only using very experienced subjects, I did a small study on random people but identifying how well people can learn to do this or whether we can in fact learn it at all might be interesting, doesn´t require much specialised gear either.

Wet cam holding strength vs dry cam holding strength
Impact forces w different belay devices in more realistic settings than have been tested

Pulley and Ascender failure.

Various pulleys (teeth and not) failing in hauling?

Ascenders (prussik, tibloc, jumar...) cutting/shredding the rope under dynamic forces?

Just a few ideas that crossed my mind.

I'd like to see a test for microcracks. Chuck a couple carabiners off a cliff and see how they hold up in a pull test compared to carabiners that haven't been dropped.

My suggestion would be to pick a topic that has either not been tested yet or a topic that does not have much testing data available on the net about it. About 80% of the suggestions mentioned so far in here have been tested and their results are posted on the Internet.

ascenders, knots, dropped biners and more tested:
youtube.com/watch?v=I0J_pg9…

hey 20kn, where can we find tests of sun exposed slings?

and if memory serves, gabe o has some vids of small gear (blue, green aliens) getting drop tested "on the rocks", think i saw it in one of the bounce testing threads.

could have my source wrong though- anyone?

Tayte Campbell wrote:I'd like to see a test for microcracks. Chuck a couple carabiners off a cliff and see how they hold up in a pull test compared to carabiners that haven't been dropped.

Make sure you scream "ROCK!!" before any carabiner chucking.