UKC

UKC and BMC test gear to destruction:

Recent discussion on the UKClimbing.com forums about the strength of knotted slings has prompted UKClimbing.com to team up with The BMC and run some equipment tests.

Read more at http://www.ukclimbing.com/news/item.php?id=48095

In reply to UKC News:

That's a bit scary! I have some of those krabs, although I only use them on the rope end for this reason, it always worried me a bit.

A few questions though:

Which other karabiners did this scenario occur with?

Did it only occur if they were *clipped* in this way? I.e. could the nut be made to sit in this position just through the natural action of the rope or was it only when it was clipped properly? (all of the pics have the nut trapped by the wire-gate)

In reply to UKC News: anyone interested in the strength of gear will also find this link interesting http://www.blackdiamondequipment.com/scene/beta/qc_kp.php

In reply to UKC News:

Interesting article. Are the results of the sling tests somewhere as well?

In reply to alansage: Hi Alan,

As it says in the news report, we will publish the sling report soon. (I haven't edited the video yet - don't tell Mick Ryan, he'll tell me off!

Probably next week or the week after.

Cheers,

Jack

In reply to katonka: Hi Katonka, I'm sure Dan Middleton will be along at some point to answer properly, but I'll give my opinion.

We found that lots of different krabs can get loaded like this - so check yours.

It would probably occur if you were rushing (pumped? I usually am!) and accidentally clipped like that.

Dan told me that he has had quite a few accident reports sent in to the BMC where this has occurred, so it does happen.

The message is: clip carefully!

Cheers - safe climbing!

Jack

In reply to katonka: Hi Katonka,

It can happen with pretty much every krab ever made whether solid gate, wiregate or screwgate except those that have a notchless nose (eg Petzl Spirit, DMM Shield, WC Helium). If you think about it, the wire on a nut is inconveniently similar to the wire or bar in the gate that engages with the notch in the nose on a conventional krab.

UKC are right to bring this up, because it is something that all climbers should be aware of, but you have to keep the risk in perspective. Probably more than 90% of krabs out there in use can do this but only one or two actually do each year. Be vigilant, but don't be scared.

Iain

In reply to katonka:
Just read this bit again:

It can occur by the wire hanging in the tiny notch behind the gate, but with the gate properly closed. (It is pretty unlikely since the action of the rope is likely to unseat it so the krab falls to a more sensible position but it is possible.) This is also a danger because the krab is cross-loaded, but not quite as dire as the example in the video. In the video example the krabs are effectively held cross-loaded and gate-open, which is how they fail at such a low load.

In reply to CragX Shop: Hey Iain, you after my job or something? I agree with what you've said btw. To put this in perspective, we've had 5 of these nose hooked krabs sent in after they have broken in the last decade. That's not many, but better if it was none!

In reply to UKC News:

I would hope this would be fairly obvious to most climbers. This would happen only because you dont notice it, so I guess the message is just to give your gear a second glance to make sure its seated correctly.

Its worth noting that this is far worse than just a gate stuck open, its that the nut is placing a higher moment on a carabiners weakest point as well as keeping the gate open. Hence why it failed at a measly 3kN and not the 7-9kN it's rated to (open).

In reply to Silum:

Hopefully obvious to more now.

In reply to UKC News: I would suggest that even though it is much weaker, it is stronger than a "slump onto the rope" unless you have been particularly hiting the pies! 3kN is the same as some microwires and equivalent to the force due to a static hanging mass of around 300kg. Admittedly you wouldn't have to fall far, and with an over zealous belayer, these forces could easily be generated.

Nevertheless, it is always useful to learn from other peoples unfortunate mistakes, and as Mick and Jack say, hopefully we will take the extra fraction of second to check it hasn't happened to us.

In reply to Jack Geldard - Editor - UKC:

Cheers Jack, looking forward to it - have wondered frequently about this...

In reply to alansage: Yep - this is a great piece. I don't think I've ever managed to get a krab to hang up like that but clearly others have, and some have then even fallen onto them. The current BD catalogue has a pic of how it can happen with a wire gate and a bolt as well.

Anyways - good job UKC, just the type of content that the web can do better than a mag. Look forward to the next one.

In reply to UKC News:
If anyone from DMM is reading this thread...
Do you also test your gear with dynamic loads, to more accurately mimic the loading found in real climbing? The reason I mention this is obviously that applying a load to the karabiner of approaching 3KN for 10 seconds (it looks like), is not the same as a much shorter peak loading found in climbing? If you tested the krabs under a dynamic load in this configuration, what values did you record? Thanks

To anyone else reading this thread...
Does anyone out there know of any empirical data of the forces generated in real climbing, rather than modelling (either theoretical or physical)?

In reply to Locus:

If you watched the video you would have seen plenty of dynamic testing. Watch closer. (0:22)

In reply to Silum:
Hi Silum.

In a word, doh. Unfortunately I was interrupted on the first part of the video and picked up at the point where the guy from the BMC was describing the situation under which failure occurred.
It would be interesting to know though if the krabs were dynamically tested when nose-hooked?

In reply to Locus:


Being as the item was about krabs clipped in that way you'd strongly suspect that's how those tests were performed.

jk

In reply to jkarran:

Dynamic testing isn't required, no (and isn't shown in the video for testing the nose of the crab hooked). Dynamic testing is only needed to give us real numbers on fall forces, in the real world. Static testing is where we can see precisely when the component fails, dynamic testing isn't needed. Static testing still happens only over a few seconds so fatigue isn't an issue, force applied on different parts of the carabiner is the issue.

An example of this is a 2m fall onto a bit of gear is the exact same force applied to as a 2m fall onto a poorly clipped piece of gear! We dont need to test both, static is the only 'practical' way to give us a failure reading.

In reply to UKC News:
I'm amazed people do end up place wires clipped like this, i never pass any gear without giving it a good shake, tug, waggle etc. just to settle my mind about how solid it is, Without this i'd be bricking it all the way to the next gear.
pretty much every snap gate in my rack is a prowire as tested so unless the very nice people at DMM want to send me some free clean nose clippers i'll have to stick with my current routine.

In reply to Silum:


You're right, looking closer that's just some filler material in the video presumably to add a little excitement. It actually looks like knotted sling testing.

jk
<who probably should have watched the clip closer before commenting>

In reply to James Moyle:
Fair point. You have to be honest with people and not scare them into agreeing. DMM make several models of nuts which are all rated to less than 2kn in the smallest sizes. Writing 'Any fall...will very likely break the karabiner' twice in a short article is a little extreme. The same could be said of any number of small oversights. I am pretty sure that no climber no matter how new to the sport would look at a karabiner attached to a wire in that way and happily climb on.

Has the production on the Shields been upped yet?

In reply to gethin_allen:

Good habit to have Gethin. It's important to focus on the real point here. Check your placements, check they are clipped properly, check gates oriented the correct way with respect to the rope and rock and so on. We didn't look at snags on tape - just as likely perhaps?

As we didn't have a pool of every krab on the market, and every wire, to see which were most likely to get snagged, it's unfair and dangerous to focus on particular models of krab. Some models are more easily snagged than the one we tested for example. I've got a bunch of Prowires* on my rack, and until they wear out (quite a while!) I'll carry on using them as they are an excellent bit of kit. Mind you, those Phantoms* are so light...

*other karabiners are available!

In reply to UKC News:

Great article, thanks to everyone concerned. I'll watch the knotted sling test with great interest too.

In reply to Wrongfoot: For anyone that is interested. The lovely people at DMM will be bringing a pull-tester on to our stand at Cliffhanger (11th/12th July in Sheffield) so you can see pull-testing in action on krabs. If you bring any old krabs we'll put them through their paces for oyu on the spot.
Iain