Here’s food for thought…
If certain aluminum biners have been tested from drops of 3000′ and found to maintain their strength and functionality, then it might very well be said that such a biner could survive a drop from any height. Here’s my reasoning: I don’t know what the terminal velocity of a biner is nor how long it takes to reach terminal, but I would suspect that 3000′ is adequate (for comparison a human body takes around 1000′ to reach its terminal velocity – differing slightly depending on body position, weight to surface area ratio, etc.). If the tested biners did reach terminal then it doesn’t matter how much higher they were dropped, they’ll still likely test out OK. Of course, a biner may strike the ground in a variety of orientations so that might affect the outcome (ie, is their a difference whether the biner impacts along it’s minor axis, major axis, flat, vertical, locked, unlocked, etc.).
Silly thoughts, perhaps, but…
Moab Matt
Tom Jones
Sorry for my flippant answer to your first inquiry. Here’s a more dignified discourse:
1. Yes, we have done some testing. We test a lot of biners that people send in with stories, and that includes quite a few dropped from the top of El Cap. Many years ago, we also dropped things down a shaft onto concrete multiple times. In all cases no degradation of strength was found.
2. No, this is far from complete. We discussed what it would take to do a scientific test. Tying streamers to the biners to make them hit a specific way. Figuring out what we think the least desirable impact points are. And since you are looking for something that is a “freak occurance”, you have to test many many many biners. Not practical.
3. Nothing in it for BD. We’re not so interested in the extra 200 biners a year we sell because of BRDTHFM (Biner Retirement Due To High Fall Myth). But saying “Yes, no problem”, and then having someone get hurt because they misinterpreted (ie, sticky gate from deformation leads to open gate failure; big nick leads to stress riser leads to failure; etc.) would be bad, real bad.
4. Just because a lot of people believe it, does not make it true. When we test things at BD, we try to test enough to get some statistical significance. Typically we test 10 of anything just to get started. We take data from 200 biner breaks minimum to set biner specifications for the catalog. Breaking one of anything just tells you what that one broke at. Testing two tells you what two broke at. At three, you might start to get an idea of what is going on. Etc.
5. We don’t make steel biners. Steel is a different story. Aluminum is an incredibly robust material, especially the drawn rod stock, then cold forged as most biners are made. Cracking can be a problem in aluminum, but you can see it. Some of the older folks out there probably have little cracks running from some of their gate rivets off the ends of the gate. These biners should be retired.
6. Climbing gear is a lot less reliable than a lot of people think. Inspect your gear. Look at it carefully for problems. Be skeptical. Be smart. Be Safe.
Tom
— In canyons@y…, matt@d… wrote: > Here’s food for thought…
If certain aluminum biners have been tested from drops of 3000′ and > found to maintain their strength and functionality, then it might very > well be said that such a biner could survive a drop from any height. > Here’s my reasoning: I don’t know what the terminal velocity of a > biner is nor how long it takes to reach terminal, but I would suspect > that 3000′ is adequate (for comparison a human body takes around 1000′ > to reach its terminal velocity – differing slightly depending on body > position, weight to surface area ratio, etc.). If the tested biners > did reach terminal then it doesn’t matter how much higher they were > dropped, they’ll still likely test out OK. Of course, a biner may > strike the ground in a variety of orientations so that might affect > the outcome (ie, is their a difference whether the biner impacts along > it’s minor axis, major axis, flat, vertical, locked, unlocked, etc.).
Silly thoughts, perhaps, but…
Moab Matt