Rappel Test for Sudden Accidental Disconnect

[shibumi]

[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.

What I did was to take my rack, load it so that it was levered against the gate of the biner (locked) and bounce as
hard as I could against it (including jumping up as high as I could (15' rope in a tree) and coming down as hard as I
could on it. I couldn't break it. Granted, it was some skanky old SMC aluminum biner. I didn't try it with an 8
or other device, mine wasn't testing, just a demo to see what I could see.

Another aside, to add to my previous post: I also teach novices to check their connections before
committing to them. Not just a visual check, but a feel as well. It's so much of a habit for me that I
don't even realize I am doing it when I cave.

Andy: Where I do most of my caving, you do have to take your rappel device on an off rope a lot.
I've never felt that there was a significant increase in risk <for me>.

[Anonymous_Coward]

Andy: Where I do most of my caving, you do have to take your rappel device on an off rope a lot.
I've never felt that there was a significant increase in risk <for me>.

Just to clarify, at the risk of , I was referring to taking the rack on and off the harness, not the rope.

[shibumi]

Andy: Where I do most of my caving, you do have to take your rappel device on an off rope a lot.
I've never felt that there was a significant increase in risk <for me>.

Just to clarify, at the risk of , I was referring to taking the rack on and off the harness, not the rope.

My bad, I was unclear. I meant to say that I take the rack on and off the rope a lot with caving in between, a lot of times
with squeezes and the like, so I also take my device off my harness frequently.

Apologies for being unclear.

[gdstorrick]

There are quite a few posts here and I don't want to discuss them all, but I will add one observation - or more precisely, information on an observation.

I have personnally witnessed a person rappelling with a figure eight weight the eight, which then twisted down so that it rode on a locked carabiner gate, which broke the gate off, letting the eight disconnect, and the person fell.

There is no doubt that they rigged the eight with a twist that they should not have had. There is no doubt whatsoever that the carabiner was locked and that it was a major name brand carabiner. There is no doubt that it broke anyway. And there is no doubt that the person who fell was heavier than many of us. At least they were not seriously hurt.

The relevant points are that (1) I do not believe that carabiners are adequately strong when improperly loaded across the gate, and (2) bad things that cannot possibly happen sometimes do.

I want to say that I do not ever use a single carabiner for attaching a rappel device to my harness. I want to say that caving, I always connect directly to my harness maillon (not all harnesses really allow this). Climbing, well, ...opposed 'biners when possible. Sometimes I've used a rappel device that I would not recommend (don't ask why). At least the big maillon is the norm for me.

Do not EVER do ANY form of SRT and then you'll be relatively safe from SRT accidents. Almost. Until I fall and land on you.

----> Gary Storrick

[fuzzy-hair-man]

I think these got mentioned last time this subject came up but they haven't been mentioned in this thread yet.

Perhaps these carabiners will go a long way to preventing the loading of carabiner gates, there are other reasons to have either a carabiner or QAS clipped in whilst loading and unlocking your descender so it doesn't eliminate these steps.


Belay Master 2009


Belay Master

[gdstorrick]

Post deleted.

[fuzzy-hair-man]

They have their place, for sure, but I've never found a good substitute for moving my brain switch to the "ON" position. After all, SRT is nothing more than a vehicle for natural (de)selection, although Bob Thrun and I have often wondered why it is so inefficient.

I agree entirely, I only posted them because I thought it relevant.
I'm always skeptical about and dislike equipment designed to make up for deficiencies in the person using it, at the risk of going off topic it's one of my reasons for liking a bobbin over a Stop, and my liking for a quicker descender as versus a slower descender. But I'm getting off topic here and moving into Descender Wars.

In this case I don't really see a downside to this type of carabiner, the safety doesn't detract from the utility of the item as far as I can see, but that doesn't mean I'm going to buy one though, and in my opinion good technique* can avoid this happening and should detect it if it does. This certainly does not mean you don't minimize risk wherever possible but rather be aware of where the attempt to minimize risk becomes counter productive or creates scope for other more risky behaviour.

*By good technique I mean rigging your descender as tight as possible below the anchor or rebelay (a longer short cowstail might help here), and allowing a minimum of slack to develop when you stand up to release your cowstail, finally before weighting you look at what you're weighting to see that everything is oriented correctly and finally you don't just flop down** but slowly lower yourself gently back down onto the descender. These steps would go along way to avoiding the problem in the first place, then if it did occur you'd see it before you weighted your descender, if for some reason you didn't see it you'd be weighting it softly enough that you'd likely not damage anything. If all of that fails you still have a long cowstail or QAS hooked in.

**As a general rule don't flop onto anything but make all moves gentle and deliberate, the rigging is your friend treat it nicely.

I particularly dislike equipment designed to provide safeties where these safeties can get in the way of the user's use of the item, essentially a case of the cure being worse than the disease.

Myself I'd much rather people take vertical work seriously and realize they have their own life in their hands if you stuff up you die, if you aren't prepared to risk this don't get on a rope, practice and good technique are your best defence IMO. Risk can only to a limited extent be factored out to equipment or others on the trip, a person should be encouraged to rely on themselves and take responsibility for their own safety.

Put simply my vertical philosophy is: don't assume anyone (or anything) but you will save you.

[Tim White]

I particularly dislike equipment designed to provide safeties where these safeties can get in the way of the user's use of the item, essentially a case of the cure being worse than the disease.

Myself I'd much rather people take vertical work seriously and realize they have their own life in their hands if you stuff up you die, if you aren't prepared to risk this don't get on a rope, practice and good technique are your best defence IMO. Risk can only to a limited extent be factored out to equipment or others on the trip, a person should be encouraged to rely on themselves and take responsibility for their own safety.

Put simply my vertical philosophy is: don't assume anyone (or anything) but you will save you.

Some of the best comments that I have ever seen on this forum!
I may have that opinion due to the fact that is my philosophy too.

[gdstorrick]

Post deleted.

[Chads93GT]

All this talk makes me wonder how many people perform routine maintenance/cleaning on their biners/ascenders/decenders to keep grime/mud/dirt/sand out, joints working properly and no corrosion. I just noticed the steel snap rings in my Black diamond locking biners were rusting the other night so i wire brushed them and oiled them, as well as the springs in the hinges. I think of gear as your life line,a nd the best way to tell if its properly working or in good shape to use, is to keep it as clean as possible

[NZcaver]

All this talk makes me wonder how many people perform routine maintenance/cleaning on their biners/ascenders/decenders to keep grime/mud/dirt/sand out, joints working properly and no corrosion.

Check.

[Carl Amundson]

All this talk makes me wonder how many people perform routine maintenance/cleaning on their biners/ascenders/decenders to keep grime/mud/dirt/sand out, joints working properly and no corrosion.

Check.

Every time I clean my gear, I clean and inspect biners and ascenders.
It's what keeps me alive on rope.

[Ralph E. Powers]

All this talk makes me wonder how many people perform routine maintenance/cleaning on their biners/ascenders/decenders to keep grime/mud/dirt/sand out, joints working properly and no corrosion.

Over here too.

[Geary]

This is an interesting thread and thought I would offer some comment.

A number of years ago, I also switched from using carabiners to a maillon for connecting my rappel device to my harness. I was told it was much safer as a maillon can handle a multi directional load and that’s the way the European’s were doing it so it must be good. On a couple of occasions, I even used a maillon on a bobbin (without incident, thankfully). The use of a maillon made some sense but now I’m having second thoughts. Not because of this thread but from direct field observation and experience.
A couple of points, a sudden accidental disconnect can occur almost anytime you have metal on metal contact. Be this two biners or a biner and almost any rappel device. This includes a standard rappel rack, micro rack, most Figure 8’s, except the Piranha, etc. The discount possible when you have a biner attached to a biner, also called chaining biners, has been well known for many years among rock climbing circles. It is eliminated by connecting biners to each other using a runner (loop of webbing). Note that locking biners are rarely used in rock climbing where biners commonly receive much greater loads then during general caving practices. While I never use a carabiner to clip directly into a rope while rock climbing, it is not an uncommon practice when top roping. There is also an opportunity for the gate of the carabiner to have a sizeable stress placed on it from falling a few feet before tension is applied from the belay. I am sure that at times, these biners are not locked, yet climbing accidents from biner failure is relatively uncommon.

If one is going to use a carabiner to clip into a rappel device, it is advised that you make sure it is locked. If you are really paranoid, you can always use two locking carabiner, opposite and opposed. However, I think that an unlocked carabiner provides better protection than an unlocked maillon.
Just like a locking carabiner, the proper use of the maillon requires that it be locked down. I have seen two maillons, after continued use, unlock. I suspect one from vibration and one from unscrewing from the gate touching a moving rope. The first incident occurred when a delta maillon was used to hold a pulley to feed 300 feet of rope for practice climbing. The pulley system was used for about 6 hours, hanging in a tree about 30 feet above the ground. The pulley was connected and checked by two people when it was attached to the rope. It was noted that the maillon gate was very easy to spin tight when attaching the pulley. The rope was used at the end of the day to demonstrate a pickoff. When the weight of two individuals was applied to the rope, the delta actually bent, opening a wide gap which was felt by the climbers. At that point, the two climbers were lowered to the ground without injury. Upon examination, the threads on the maillon were not damaged nor was the maillon shock loaded in any way during the day. The pulley did not disengage from the maillon because it was caught in one of the three angles in the delta maillon.
The second incident occurred when a mallion was used to connect a quick attachment ascender (got I hate that term) to a seat harness as part of a rope walker system. After climbing about 45 feet on rope and as I was getting ready to pass over the lip, I looked down and the maillon was fully opened. I know that I checked the maillon before climbing and it was locked. I did note that the rope was running against the screw gate part of the mallion when I inspected it at the top of the drop. The gate on the maillon was also very easy to spin tight when it was attached to the harness.

Given a choice between using a unlocked maillon and an unlocked biner, I would choose the biner. Given a choice, I would prefer to use to not use either device unlocked. I have also seen a number of new cavers who have not closed the screw gates on their seat harness maillon when attaching their gear. These issues were caught during the preflight inspection.

I think the pre flight inspection should include two important steps. The first is to touch, point or observe each piece of gear in a systematic process to make sure that it is properly configured and attached. I start with the rope, knot, bolts, hanger, rappel device, rappel attachment, seat harness, helmet, gloves, and me. Then and only then do I initiate the second step which is to load your equipment with a second safety back up before fully committing to the rappel.
(Note that a maillon with the gate open will still remain attached to a rappel device. Loading and unloading the device may result in detachment.)
Be careful out there.

Geary Schindel

[Vertigo]

I know exactly what you are talking about. Happened to my QAS when I was climbing Fantastic Pit. I always check the carabiners before I get on rope, and whenever I decide to sit back down in my harness. The carabiner attaching the QAS to my harness had come unscrewed, but just imagine it had been a maillion. It very well might have fallen away, along with my QAS, all the way down the pit. I use a Mitchell system, so I could have performed a changeover safely, but I would have looked something like this In my opinion maillions don't do well around moving parts and rub points. I have become slightly paranoid about the delta maillions on my stiff steps.