Dyneema vs Nylon Sling Drop Test
By Rocky Thompson on July 13th, 2010
I have this notion that climbing gear is built to such wildly high specifications that there’s no way anything could ever break. Sure, if I accidentally tied off to the gear slings on the side of my harness at a belay station, I wouldn’t expect that to hold, but you expect Dyneema slings to hold through almost anything. This DMM Climbing video will make you think twice about the gear you carry. They show Dyneema and nylon slings getting run through some drop tests. It’s also a nice reminder to make sure there’s no slack in the system.
Thanks Adam
Tags: Climbing
S.R.E.NE: SOLID, REDUNDANT, EQUALIZED, NO EXTENSION. Build your belay anchors using this acronym and this should not be a problem. Good info. though.
These tests create a false impression. The force felt by the sling is given by F=dp/dt where dp is the change in momentum of the lead weight and dt is the time over which the momentum changed. By using a solid weight in the tests with all pieces of the system engineered to be static, the testers made dt extremely small. This causes the force to spike up to very large values for a brief moment and break the slings. But the human body in a harness would NEVER act the same as a solid weight. We are floppy and squishy blobs. If a human was in a harness in that test, the slings never would have broken. The momentum change would have been spread over a larger time interval and F would have remained small. I’m suspicious that the people who did this test are willfully misinforming climbers…
Not sure I fully understand the science (actually I’m pretty sure I didn’t get it!!!) of the test but what I got are the general messages of “don’t build anchors with slings” and “don’t leave slack in an anchoring system”. On those points, the experience was a success.