Self belay when climbing with static slings
We often use slings for self-belaying. Be it at the belay station for alpine or multipitch climbing, cleaning anchors during sport climbing or for resting in the via ferrata. In contrast to dynamic kernmantle ropes, slings are designed for static loads. You have to be aware of this, because in use this has decisive consequences.
Falling into static slings can quickly become problematic. The material is not designed to absorb dynamic loads. Even a fall from a relatively low height can lead to failure.
Experimental setup: We bring the practice into the lab
To determine the critical falling heights at which the system fails, we set up a scenario and tested different heights and materials. For this purpose, the different self belay slings were fixed to an anchor point by means of carabiners (simulation of abseiling) and connected to a fall mass (80 kg) by means of a bowline in tie-in point. The slings were sewn slings according to EN 566 with a minimum breaking strength of 22 kN and a length of 120 cm. The falling mass was triggered from different heights and the height at which failure occurred was determined. The heights were increased in 10 cm steps and the height at which failure of the sling occurs was named as the critical falling height.