VIDEO: Broken Karabiner - UKC / BMC Safety Videoby Jack Geldard - Editor - UKC Jun/2009
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UKC and the BMC headed down to the DMM factory in Llanberis to make use of their testing equipment and also to probe gear expert Streaky Desroy for some additional knowledge. (Streaky was the star of our previous safety video)
We tested slings on belays. We also tested a common scenario that causes karabiners to fail. In this first video from that testing day we will concentrate on the karabiners. The sling test is coming soon.
Dan Middleton from The BMC gave the following report:
Climbing equipment has never been as well made and engineered as it is today. Failures are rare, but if they do happen, the BMC Technical Committee is on hand to investigate.
Over the last few years a number of incidents were reported where karabiners had broken unexpectedly. In each case, it appeared that the cable of the wire or nut had been accidentally clipped into the nose hook of the karabiner. In the subsequent fall, the karabiner had easily broken, in some cases resulting in a ground fall and injury.
A recent trip to the DMM factory in Llanberis gave the opportunity to talk to the experts there, and to make use of their test facilities. The legend that is Streaky Desroy was there to lend a hand. We decided to test what happens to a karabiner when it is loaded in this way. What did we find out?
A krab clipped in this way breaks at only around 3kN. What does that mean in reality? It means that pretty much any fall, even just a slump onto the rope, will very likely break the karabiner. If you're close to the deck or a ledge, or if the route is run-out, then you could be in serious trouble.
“Any fall, even just a slump onto the rope, will very likely break the karabiner”
Now for the good news! In performing our tests, we found that not all karabiners would trap the wire in this way. In fact, most modern designs have a smooth nose profile or keylock nose and can't trap the wire at all. With the older designs that could trap the wire, this only happened with smaller wired nuts using a small diameter cable.
So, what advice can we give following these tests? Replace all your older krabs for new modern ones? Yes, if you like – Streaky has to pay for his collection of tasteful Hawaiian shirts somehow. Alternatively, get in the habit of checking when you clip. Make sure you've done it right before gunning it upwards towards the next runner placement – it could save you from a nasty surprise!
Thanks go to DMM for the use of their facilities and to Streaky Desroy for his expertise.