Rappel Test for Sudden Accidental Disconnect

[wyandottecaver]

Were these biners locked? It appears the article is saying that the 8 forced the gate inwards, breaking the locking sleeve and allowing the gate to open. But later says the sleeve was screwed upwards..?

[jharman2]

[manifesto]

This is why I rarely opine on cavechat. However, this is one topic that I feel so strongly about that I couldn't keep my fingers shut.

Cross-loading a carabiner is not a use outside of its intended purpose. Carabiners are designed and tested to withstand short-axis loading in all but the most severe loading situations.

I respectfully disagree. Just because a biner can withstand a cross loading event does not mean that it is INTENDED to be loaded in this fashion. You can also bend the sleeve and not be able to open the biner. This failure mode requires MUCH less force than the quoted 7kN and while not fatal can cause problems removing the rack from the D-Link. EK pointed out a valid situation where it would be advantageous to remove the rack from the rope. With a bent locking sleeve this is not possible.

When you say "control hand" do you mean the hand that holds the rope below the device (which, for fixed friction devices and "hybrid" devices like the micro rack, is called the "brake hand"), or do you mean the hand that controls spacing of the bars? I believe the former is the standard meaning of the term "control hand" among rack-users.

I am referencing Figure 5-20 page 106 and Figure 5-51 page 121 of On Rope New Revised Edition. I use this nomenclature when describing any rappel device. On page 106 of On Rope the Control and Brake hands are defined as:

Brake Hand: The Hand that provides braking action on the standing line below the rappel device.

Control Hand: The hand that holds and moves the bars up/down or on/off and or to add or subtract friction from the rope. On other devices, this hand is often the balance hand held above the rappel device.

The situation you're describing where my hand is pinched between the carabiner and the rack sounds unlikely...

Yes it is highly unlikely. I was only shooting from the hip with one of the many possible scenarios that could cause an accident. Most accidents occur because of a low probability failure mode that was compounded by bad judgment.

I accept your hierarchy of safety in rack attachment, at least in terms of detachment risk.

I should have made clear I was only speaking with respect to detachment risk in my previous post.

Many rack users, especially male users and myself included, find it downright painful to climb with a rack swinging around between our legs, so we use a detachment connector (carabiner or maillon) to enable us to remove it from the harness maillon when we're not using it.

Likewise I take my rack off and clip it to my right hand gear loop. Screw link attachment closed and clipped to the gear loop with a locking biner that is also closed. This way if I have to negotiate a tight spot on rope I reduce the possibility of loosing the rack.

The additional time and effort that it takes to operate a maillon as compared to a carabiner complicates any already-complicated procedure and could worsen any already-bad situation.

To me peace of mind is worth a few extra seconds...or even using a wrench.

Actually, the reason that compels me to use a carabiner rather than a maillon to attach my rack to my harness maillon is that, when transferring the rack to or from the harness maillon while suspended from the rope, there is a risk of dropping the rack off the open maillon or the open maillon off the rack. With a carabiner, you can trap the rack between the open gate the lower-end (i.e. hinge-end) of the carabiner.

There is risk in dropping the whole assembly too.

Unless you are using a ropewalker. When changing over you need the slop provided by an extra link between the rack and harness. Try it. But, do it on a rope rigged thru a pulley, so you can be lowered down if need be.

I will give that a try!

[/manifesto]

[Scott McCrea]

I got a couple of requests, so I formatted the original post into a Word doc and a PDF that can be freely published in newsletters or wherever. If you would like it, just PM or email me and I'll send you the file.

[graveleye]

I learned to use two locking biners to attach my rack to my maillon, turned opposite of one another - one with the gate facing in and one facing out. Probably overkill, but I'm paranoid. I'm so paranoid in fact that I double check all my biners and so forth several times, then let someone else check them again. As far as the rappel test goes, that's just how I was taught from the beginning so I don't know any other way. It just makes sense if your freaking life is on the line, and gives me a chance to make sure my biners are oriented correctly. I've never tried to attach my descender directly to my maillon, but it seems to me that would put it in a less ergonomic place for my comfort.

Don't be a wiener, check your biner.

Also, instead of taking my rack off, or having it banging around between my legs, I just pull it to the side and biner it to my accessory loop. I don't like the idea of having it unattached when I'm on rope because I'm afraid I might drop it should I have to reattach it to my d-link. Then when I'm walking around it's not banging my kneecaps or threatening to cause me to sing soprano.

[StevenSmith]

I'm fairly new to caving and rope work. I only started in 2008. I have all new Vertical Gear and I'm practicing as often as I can but I have very little cave experience on rope. I've only done a hand-full of rappels and ascensions besides tree practice. I built a Mitchell system for vertical climbing. I have been using a Large Screw-gate Petzl Carabiner with the red "Open" indicator to attach my harness to my welded 6 bar J-rack. I have noticed that it is very easy to get smaller carabiners positioned cross-gate if I'm not paying attention. The larger Carabiner seems easier to work with.

With that said, I also have a Mallion that I'm not even using. Based on this conversation, I'm thinking about using the Carabiner to attach my safety line, etc. to my harness when I'm ascending and switch over to use the Mallion when I do my changeover to the rack. Does this sound like the right thing to do?

Steven Smith

[Stridergdm]

Scanning over this thread, I think some are sort of missing the point. It doesn't really matter how strong a carabiner is or isn't, or if cross-loading is ok or not. Or even how you attach your descent device to your harness.

SAD happens. There are bodies to prove it. It can happen in more than just the manner originally posted. Hell, someone can "suicide" rig their rack and yet have it correctly clipped into their harness. (have you ever heard a suicide rack "pop" under load? It's scary. Fortunately my friend was only 20' off the ground (with an ambulance 20' away) and caught himself in time on the balcony edge.)

Scott's original post makes a very important: Don't commit yourself to your rappel device until you've tested it, while still rigged into something solid. It can be your QAS on the rope, a carabiner clipped into a rebelay or a traverse line or something.

Use the rappel test. Every time. The life you save will be your own.

[Anonymous_Coward]

When I was first putting together an SRT system, my friend that was helping me said, "You need to use a maillon to connect your rack to the D-ring instead of a carabiner or you'll die like my friend."

His friend died because of "SAD" and I'm sure is one of the fatalities that has already been mentioned in this thread. At an impressionable period of my SRT career, my friend's statement made a big impression on me. As a result, I have always used a wrench-tightened maillon as a rack attachment. Now that time and thousands of feet of rope have gone by, the logic of his statement is obvious.

In light of the facts, I don't really understand why anyone would use a carabiner. It is one more potential failure point to have to check and worry about. I agree with Scott that gear is safe, humans are not. So I am talking about potential human failure, not gear failure. This is one SRT debate where we actually do have the theoretical "pile of dead bodies". Thankfully, it is so far a very small pile.

Were these biners locked? It appears the article is saying that the 8 forced the gate inwards, breaking the locking sleeve and allowing the gate to open. But later says the sleeve was screwed upwards..?

I think cross-loading causing gate breakage on rappel is a very remote possibility. The real danger is from an unlocked biner you are not aware of.

The biners may or may not start out locked. Even if they do, the locking sleeve can be worked loose and you end up with an unlocked biner. With "wear your gear" multi-drop caving, the stupid biner lock sleeve has to be visually checked at each and every drop/rebelay. One more headache and it is easily overlooked when tired or in a waterfall or whatever. Take Scott's advice and KISS. One way to keep it simple is to eliminate this unecessary and potentially dangerous link in the system.

I know someone will mention that maillons can come open too, but it is much more unlikely and can be prevented by orienting the D-ring in the proper direction. The smaller maillon I use for rack attachment is wrench tightened and I never open it. I just slip it on the D-ring when kitting up. The only things I have to visually check before rappelling are my leg loops and D-ring closure. Like graveleye, I check them about 5 times. I would hate to have to remember to look at something else. If I had to do it at every rebelay, that would be maddening.

Ek, nobody likes a rack whacking them in the balls. Just clip it over to the side like someone else already mentioned.

If you insist on using a carabiner in spite of the facts, then for God's sake do the rappel test that Scott describes EVERY time. Your life depends on it.

[Anonymous_Coward]

Well, I cross-posted with Stridergdm.

He is right of course, the rappel test negates all the other arguments.

However, I maintain that I am not missing the point, rather making a slightly different one:

In light of the facts, a carabiner is not the safest way to attach your rack to your harness.

Okay, fire away......

[shibumi]

Well, I cross-posted with Stridergdm.

He is right of course, the rappel test negates all the other arguments.

However, I maintain that I am not missing the point, rather making a slightly different one:

In light of the facts, a carabiner is not the safest way to attach your rack to your harness.

Okay, fire away......

Using a maillon is a PITA when you are taking the descent device on and off of the harness
a lot. My habit, and those I ingrain in my students is: In preparing to rappel,
first put on QAS. Then descent device. Test descent device. Take off QAS. I also
teach them that the absolute safest way to attach the descent device is directly to the harness
via the half-moon, the next safest way is via maillon to HM, and the least safe, but still
acceptable way is via locking carabiner to HM.

I rappel with my descent device attached via carabiner. It's my preference because I like
to have the descent device out of the way when I am not rappeling.

Aside to Scott: I have tried to break crossloaded aluminum carabiners under normal
forseeable loads and like your trial, was unable to do so.

[chh]

Just something I tend to do habitually is glance at locker I'm using to make sure that the sleeve is actually over the nose of the carabiner. While it usually doesn't, a bunch of sticky mud, or small sand particles can impede a screw or autolock sleeve making it "feel" closed when you are handling it when it may not be. I've had to really crank on some of my lockers to get them unstuck from the both the open and closed position. If you comit to making a visual examination regularly you'll catch stuff, I promise

I tend to get on a soapbox about stuff, which I won't here, but everyone gets a little cavalier from time to time regardless of what system the use and how "safe" it is. I know I do. Scott is absolutely right. Human error is what's likely to kill you, not the connection you use to your harness. I'm [u]especially[u] glad everyone made it out safe on that trip. Hey Scott, you think you could get a litter our of that cave?

[Anonymous_Coward]

Using a maillon is a PITA when you are taking the descent device on and off of the harness
a lot.

Falling to your death: Also a PITA for all involved.


Anyway, I guess it comes down to: Are you going to be taking your descender on and off throughout the trip?

If you are not, I would suggest that you not use a carabiner.

If you are, then BE CAREFUL!

Personal preference wins again. It's the American way.

[Tim White]

[I tried this a few years ago. I was fully prepared to shatter a biner and crash to the padding on the floor. But, no matter what I tried (including bouncing and bouncing a two person load), I could not break one. Anyone else care to try?

Are you (and Anmar) saying that you tried to create the SAD effect and failed? If so, I want one of the biners you use, because they must be STRONG!

I've see the test and data that a leading equipment manufacturer conducted and my personal conclusion was that ALL carabiners will fail in this type of twisting cross-loading.

[Scott McCrea]

I was trying to recreate the biner failure that Bob linked to, the Neville McMillian article. Where a fig 8 causes a lever effect on the gate of a locked biner and snapped the nose off. I did not test any cross loaded any biners.

[Scott McCrea]

BTW, we had a lengthy discussion about carabiners and maillons about three years ago. There is even a poll.

[OpenTrackRacer]

Very interesting information. I rappel with a Petzl Stop but that doesn't remove the possibility of SAD. I use a Petzl locking carabiner with a red telltale on the gate. It's pretty stable where it attaches to the harness with regard to the carabiner rotating and loading the gate. However, it's also very easy to thread the Stop incorrectly if you're not paying attention.

I (almost) always have another person check my rigging before heading down. I was never taught to use a QAS to check the rigging but it's rather obvious in hindsight. Since I always have a handled ascender attached to my long cowstail, it's easy to do as well.

Rappelling procedure changed... thank you!

Mike