Slings & Extenders

Slings, Extenders and Daisy Chains for climbing are all made of nylon (polyamide) or Dyneema®/Spectra® (polyethylene) webbing.

Dyneema® is much stronger than nylon but less elastic. According to DMM, even a 60 cm fall-factor 1 fall on to an open Dyneema® sling can generate enough impact force (16.7 kN) at the anchor to pull a Wallnut 11 wire (12 kN) apart. In fact nylon slings can also snap wires and both substances lose significant strength with wear, whilst pulling an abseil rope through a sling of either material can generate sufficient heat to weaken it or melt it completely.

It follows from this that slings and extenders should be replaced regularly (say every three years with normal use, but sooner if the look badly worn), that if you use slings in a belay system, that system should have no slack in it whatsoever, and that slings should never ever be used as a cheap via feratta clipping system. All slings should be inspected regularly and replaced if they show signs of excessive wear or damage.

There is a good article on slings on the DMM Website.