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climbnkate
Aug 5, 2005, 9:18 PM
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Hey,
I am sure that this topic has been discussed at some point but nothing came up when I searched.
I am still renting equipment from the gym and the instructors always hand me two biners; one to belay off of and one to anchor in with. Is it safe to belay and anchor in using the same carabineer?
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curt
Aug 5, 2005, 9:28 PM
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In reply to: ....Is it safe to belay and anchor in using the same carabineer?
No, that is not generally considered to be a good practice, for a number of reasons. The possibility of cross-loading the single carabiner is one. Having the option of un-clipping from an anchor while keeping the climber on belay is another. There may be additional reasons too. In a gym environment, this may not be so important, but you may as well learn good practices anyway.
Curt
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abalch
Aug 5, 2005, 9:28 PM
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If, and only if you are belaying off of the anchor. You mentioned that you were renting from a gym, so I imagine that a few places in the floor they have an anchor in the floor. If you were to place one carabiner on that anchor, and that carabiner had your belay device, than you would be belaying off of the anchor.
Since more likely, you are standing by an anchor in the floor, and belaying off of your harness, the two carabiners, one going to the anchor in the floor, with a chunk of webbing or rope from the floor to the carabiner, and using a second carbiner to attach your belay device to your harness is the better plan. In cases such as you described, you would quite likely end up loading a single carabiner incorrectly if you had the carabiner attached to your anchor, your harness, and your belay device. It is commonly called triaxial loading, anch the chance is that you will load the carabiner across it's weakest axis.
Please just stick with your gym's policy, and use a carbiner for the anchor, and one for the belay device. It is safe, the alternative is not.
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climbnkate
Aug 5, 2005, 10:31 PM
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Thank you for the quick responses. Will continue to use two biners. :)
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beesty511
Aug 5, 2005, 11:42 PM
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Tri-axial loading:
"Tri" means "three", "axis" means "direction". Tri-axial loading is when you load a biner in three directions. If you use the same biner to belay as well as anchor yourself to the floor, then there can be three directions of pull on the biner:
1) the belay loop on your harness
2) your belay device connected to the rope
3) the ground anchor
So, anytime you have three things connected to the same biner, there is a potential for tri-axial loading. So what's so bad about tri-axial loading? Biners are strongest when loaded along their length, i.e something is pulling in one direction next to the spine(the side opposite the gate), and something else is pulling in the other direction next to the spine, which is two directional loading
You want to avoid triaxial loading. When you use a second biner to anchor, then you eliminate the potential for tri-axial loading: each biner will only have two things clipped into it.
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alpnclmbr1
Aug 6, 2005, 12:11 AM
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In reply to: In reply to: ....Is it safe to belay and anchor in using the same carabineer? No, that is not generally considered to be a good practice, for a number of reasons.
That statement is generally true. Yet, in this context, it is wrong.
We are talking about a belay anchor in a gym, right?
The large majority of gyms do not require a second biner. End of story.
Tri-loading is a moot issue in regards to a second biner on a gym toprope belay.
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irockclimb
Aug 6, 2005, 3:01 AM
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yea once u get more comfortable with climbing and belay u will grow outa needa a anchor unless the gym requires it or the guy just weighs a ton more than you.
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curt
Aug 6, 2005, 4:08 AM
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In reply to: In reply to: In reply to: ....Is it safe to belay and anchor in using the same carabineer? No, that is not generally considered to be a good practice, for a number of reasons. That statement is generally true. Yet, in this context, it is wrong. We are talking about a belay anchor in a gym, right? The large majority of gyms do not require a second biner. End of story. Tri-loading is a moot issue in regards to a second biner on a gym toprope belay.
Had you actually bothered to read what I wrote, you would see that I said pretty much the same thing you did--so, if I'm "wrong" you are too.
In reply to: No, that is not generally considered to be a good practice, for a number of reasons. The possibility of cross-loading the single carabiner is one. Having the option of un-clipping from an anchor while keeping the climber on belay is another. There may be additional reasons too. In a gym environment, this may not be so important, but you may as well learn good practices anyway.
What's up with you lately, anyway?
Curt
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march
Aug 6, 2005, 4:15 AM
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In reply to: ...or the guy just weighs a ton more than you.
... or you're belaying a lead climber and they could take a decent fall pulling you off the ground or into the rock.
...or the lead climber becomes injured and you are unable to lower them, an anchor will allow you to tie them off to effect a rescue or go get help.
...or ...anyone else want to share?
Setting up a belay anchor is a good habit to get into - especially if you get into trad climbing.
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