UKC

The load drop video on UKC (dyneema/nylon) in the "Common accidents" article was very sobering(when it first came out...and also on watching it again) ....made me wonder about the effect of minus 20 C temps on slings and also on ropes. Just back from a trip to Cogne and on a couple of routes my ropes were frozen solid and my belay slings not much better. Apart from the obvious problems of handling frozen ropes etc...any science around the effect these conditions would have on the force required to cause sling/rope failure...?

In reply to joe gallacher:

Not testing on slings, but on waterlogged and frozen ropes -http://www.singingrock.com/wet-and-icy-ropes-may-be-dangerous

Not great reading for those who climb thawing icefalls..

I think the interesting bit in the DMM testing is just how much a knot reduced the strength of the dyneema sling.

In reply to joe gallacher:

Nylon rope has shown no loss of strength down to -40°C. The normal lower limit for it´s use in engineering applications is -70°C.
Dyneema increases in strength as it becomes colder, there is test data for rope down to -50°C and other work to -150°C shows no brittleness point and it is thought the streength continues to increase down to at least this point.

In reply to jimtitt:

Thanks Jim , seems a bit counter intuitive that they would survive the impact of a fall better if the stretch is frozen out of them BUT if that's what the science says.... Thanks also Gav , I came across that site earlier today too , surprising the reduction in performance when they get wet ...but a very useful heads up... cheers joe

In reply to gav p:

I would not be worried. To my knowledge there are no accounts of accidents where ropes snapped because they were wet. Matter of fact, excluding ropes running over edges, I have heard of no accounts of rope failure at all. I might be wrong though.

In reply to joe gallacher:


It's not the sling that deforms (significantly) to absorb energy if you fall onto it, it's you.

jk