SLACKTIVITY (Samuel Volery, Tobias Rodenkirch) has conducted a UV-light-exposition test in a permanent midline that was up for 7 months over summer. The tested slacklines were not in the shade but rigged in full exposition to the sun. Five different Slacktivity webbings were tested:
The main line as well as the backup have been tested. After about 1500 hours in the sun the breaking strength of the mainline has decreased an avarage of about 8kN (=800kg) and the one of the backup has decreased by about 7kN. The complete study can be read in the following pdf document.
A piece of pinkTube has been permanently rigged and sessioned for 6-8 months. It has seen between 3000 - 5000 leashfalls and was exposed to the sun for about 2 hours per day. It was located in a forest in France, near streaming water with high humidity. This piece of webbing has been break tested by the International Slackline Association. In the following article you can see the results:
If you want to find out more about forces that are occuring in highlines, then you can watch the following video. Be aware that highlines rigged with low-stretch webbing and short highlines see clearly higher peak forces compared to high-stretch webbing ones or long highlines.
TEAR IT UP
Knot breaking by SLACKTIVITY
Author: Daan Nieuwenhuis
Break tests: Daan Nieuwenhuis & Samuel Volery
Pictures by: Daan Nieuwenhuis
Since a few years the low-tension lines have become more of a standard. This new style brings new styles of rigging, one of these is tying knots in the back up webbing. But what does a knot in webbing actually hold? How does the knot influence the breaking strength of the webbing? As SLACKTIVITY we also had the goal to test out multiple knots to connect our back-up webbing to the mainline in our Type B webbings (redTube & pinkTube). This is done by making a knot in your back up webbing, and connect it to a T-Loop with a quicklink.
WARNING: Knots can be complicated and hard to check properly. Don’t use them if you’re not 100% sure that the knot is correct, or if there is nobody that has the knowledge to double check it. Even after tying a knot 20 times, mistakes can still happen. Always double check each other rigs.
Many people who see a highliner on a highline for the first time, think that the forces are very high, especially when falling into the highline (leash fall). Since the slack ("sag") in highlining is not as limiting as in longlining over ground, most highlines are much less biased and this leads to lower forces than you would like.
Check out this video and write out of the tests we did:
Because slacklining is still a young sport and there are still few materials and standards that are geared to the slackline application, material from other applications (from sports and industrial climbing to industrial applications) is used.
Here in this article it is shown that this is carabiners can be used in a few applications while slacklining. Be aware that you never use aluminum carabiners in your rig. They tend to break under cyclid load.
This video shows how the carabiner shape affects the breaking load of triangular loads.
The forces that occur during slacklining are composed of the preload force and the weight of the slackliner. This can be both static and dynamic. It is not possible to determine the forces without measuring device exactly - but one can calculate the forces in static slacklining with a formula approximately.
Here are some basic rules of the forces: