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slacklinejoe
Nov 20, 2003, 10:57 PM
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I contacted Omega about if slackline carabiners would be safe for climbing use later and I thought I'd share the results since they were actually quite interesting.
The quizzed REI and one of their quality assurance managers offered to test out various slackline setups and the pressure exerted at the carabiners to mke a safety judgement.
#1 The biggest suprise I had was a very tight primitive setup only put ~100 lbs tension on the carabiners.
#2 With a 160lb guy jumping on the same really tight setup it it still only seen a peak tension of 600lbs.
Their opinion, under the situations tested they stated that slacklines should not pull carabiners past their normal safe yeild, however that depends a lot on how your setup works and various other factors that could damage the biner. If you torque, twist or cross load the biner such as in the tightening system or at the tree sling it could render the biner unfit for life saving duty. Their take: it's still prefered that you not use biners for life supporting climbing use later since the cost is small for an extra set.
Food for thought.
Keep in mind this isn't Omega's official statement yet, but instead the results which were measured by REI on their behalf and simply an opinion from them, not an official blanket statement since there are too many things that could come into play.
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dobbsboy
Nov 21, 2003, 4:06 AM
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Last weekend we had a big slack session at the park with 8 lines set up. One of those lines was a 25ft low super tight trick line. With the line tensioned, and no person standing on the line. You could clearly see that the carabiner on each end had flexed 1/8 to 3/16 of an inch. where the gate normally closed there were wear marks visible of the above mentioned length. When we broke down the line the wear marks were no longer visible. That seems like quite a bit of stress to me, albeit it was a very tight line. Anyways i personally don't mix my climbing biners with my slack biners. I would be interested to see some test run about actual forces on the line and system while slacking.
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slacklinejoe
Nov 21, 2003, 5:06 AM
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Thats exactly what we're working on, I'm sending them out a kit to stress test to oblivion after they have some fun. They gave me a little bit more data, but I they wanted to play around with it a bit to get very in depth first.
But what you described is actually exactly what they are supposed to do under that condition. The standard is that a carabiner should stretch thats how they avoid snapping, but not stretch so much that it can't be opened under a normal body weight condition. If you couldn't open your biners under that super tight load:
1: you managed to get one heck of a tight line, as in approaching hurt your feet because it feels like cable
2: your biners were worn already
3: you should seriously consider using heavier duty biners or replacing them
That said, if they still open under that condition and they go back to their origianl shape after words you should be fine (thats what I got from them so far, not my personal opinion).
By the way, I wanted to make it doubly clear that the data in my first post is not official from either REI or Omega - a quality assurance manager from REI did it, but it wasn't sponsored by either.
I'll post the dirty little details as soon as we can get them.
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therealbovine
Nov 21, 2003, 5:27 PM
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What about open steel hooks, like the ones you sell on your lines. Any pull test info on those?
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tcollins
Nov 21, 2003, 5:47 PM
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For the little money it cost me to dedicate 3-4 BD ovals to my line set up I'm not to worried. Takes any possible issues right out of the equation.
TD
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slacklinejoe
Nov 21, 2003, 6:51 PM
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In reply to: What about open steel hooks, like the ones you sell on your lines. Any pull test info on those?
Thats exactly why they are testing one of mine to oblivion :D
Actually those stretch just the same as biners and then go back to shape afterwards and still retain their strength. I've contacted the manufacturers for those too, but haven't heard back. I know they are rated for a minimum of 2,500lbs tension, but I never seen a limitation on for amount of time or yield ratios. Thats the type of data we're working on right now.
I've been offering 'biners instead of steel S-clips as an option, or even a discount if you don't want the S-clips at all and want to supply your own biners. Thats why I was concerned about using them for climbing later.
Cross comparing those gets hairy to say the least, the industrial side is dealing with ANSI specs and such, while the climbing side doesn't; or if they do I need more links sent my way.
However, I can safely say even when we were doing tension tests on the webbing those S-clips didn't deform at all and even under extreme circumstances where I was having webbing break, I've never seen a failure.
I suppose if you cross loaded the back end that is more of a circle it might bend out of shape slightly, again that goes under extreme pressure. I intentionally cross loaded one a super tight 50' and with me jumping up and down on it there was no noticable stretching (I had a 2" backup line so if it broke it wouldn't actually send anything my way - so don't do that at home kids).
In the end, I have to concure with what Micheal Lane (Omega) and Steve Nagode (REI) came up with as a personal opinion, while slacklines seem to be pushing lots of tension, they aren't. It seems very deceiving, but aparently slacklines aren't as hard on gear as one would expect as long as you avoid cross loading and twist scenarios.
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bernard
Nov 21, 2003, 7:40 PM
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Well...... its your life..............
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slacklinejoe
Nov 25, 2003, 2:53 AM
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The best info I've gotten on the S-clips is:
break strength of about 2,500 lbs tensile --- I'm still trying to pry more out of them on specifics, they seem to be quite tight lipped except to say that it should be fine up 2,000lb tensil on a regular basis and that they are the strongest S clips you can buy in that design.
I'm not going to stop there since that isn't a good enough endorsement for me. I think I'm going to have to send them out and have them tested independantly from the kit. This of course takes forever to get results back.
I do know however they have a lot of excess strength when compared to what even a super tight slackline setup exerts as measured in the first post. Keeping in mind these are backyard setups, not highlines or super long setups, so I don't sell them for use on long lines.
I'll post more numbers when I get them.
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rogueclimber
Nov 25, 2003, 3:24 AM
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I have destroyed several biners setting slacklines.
I have destroyed several biners aid climbing.
I check them out, mix them up and don't think much about it.
Want to go climbing with me?? :lol: :lol:
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slacklinejoe
Nov 25, 2003, 4:43 AM
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In reply to: I have destroyed several biners setting slacklines. I have destroyed several biners aid climbing. I check them out, mix them up and don't think much about it. Want to go climbing with me?? :lol: :lol:
Heh, only if we use my gear :)
Seriously though, you've broke gear on slacklines? Recall any of the specs? We use 31kn locking biners since I'm paranoid and all....
How often do you retire stuff? If you broke all that, do you at least belay with known good gear? Scary stuff, I've always retired it before anything broke.
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dirko
Nov 25, 2003, 4:54 AM
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Obviously your slackline set-up is an important factor here. I always set up temporary lines, with something like a 5 to 1 set up with biners left in as an integral part of the system. If you are talking about a semi-permanent line with one biner (a line that must be cut to be taken down) you have a different situation. But with my setup, the force should be spread out among the four ovals I am using as a pulley. So even if the line generates a biner-breaking 24kN, each oval should only have to hold 6kN. The biner on the other side, should there be one, is a different matter. Wish I had a picture.
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slacklinejoe
Nov 25, 2003, 6:00 AM
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In reply to: Obviously your slackline set-up is an important factor here. I always set up temporary lines, with something like a 5 to 1 set up with biners left in as an integral part of the system. If you are talking about a semi-permanent line with one biner (a line that must be cut to be taken down) you have a different situation. But with my setup, the force should be spread out among the four ovals I am using as a pulley. So even if the line generates a biner-breaking 24kN, each oval should only have to hold 6kN. The biner on the other side, should there be one, is a different matter. Wish I had a picture.
I've seen/used the setup your describing when a friend set one up in the park, and yes it does split the force between the biners. Even with your setup super tight, I'm sure you could open the biner gates still, which means less than ~ 240 lbs of tension or less.
I'm just trying to find out the worst case scenario where one biner is used between the anchor and the line at the moment and use that data for other measurements. Knowing what stress one biner in a complex setup has is useful for that exact setup, but knowing the entire force exterted by the line can be used to estimate how many points you should have the force split to, or if redundancy is necessary.
I think for nothing else that information is useful to help find at what point redundancy should be used from the migration from small lines to medium sized lines and how beefy your tree slings / anchor points need to be.
It'd be overkill to recommend double anchor points and redundant biners on each end for a loose 30' setup that only sees a peak tension of 400lbs since you could probably tie it off without any biners or mechanical advantage at all. But at what point do you need to start backing stuff up or using heavier duty gear? Thats the type of stuff I'm trying to get at.
Maybe it seems unnecessary since people have had expereince such as statements of "I've used x type of setup at x many feet for so many years and never had a problem" but I'm trying to get a bit more scientific of an approach for saftey sake, even though I only make smaller lines and all - it's useful data when your using/building new stuff that people haven't had expereince with.
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gyngve
Nov 25, 2003, 6:06 AM
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In reply to: I contacted Omega about if slackline carabiners would be safe for climbing use later and I thought I'd share the results since they were actually quite interesting.
Just have designated slackline biners. It's a lot easier that way to keep the entire slackline setup together. And six cheap biners at $3 each is only $18...
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