It wasnâ€™t long ago when carabiners were not recognized by ANSI for tree climbing use. Now they are. Praise the Lord!
So what is a standard for life support carabiners? Locking, yes? How many actions? We have single action (screw down or screw up!), double action, and triple action varieties. Ball lock, barrel lock, and maybe other types of which I do not know about.
What about non-locking carabiners? Would you ever choose to hang with one? What standard would you go by?
What about snaps? Do recreational climbers use snaps? What kind should be used? Should the only guide for snap use be in its strength rating?
Peter, I believe that double locking and triple action mean essentially the same thing. The Sherrill catalog clarifies (or does it confuse it?) by calling these positive locking. These carabiners make two motions when automatically locking, for example the barrell slides down and twists clockwise. It takes three "actions" to open one of these (push up, twist counterclockwise, pull back the gate). The ball lock and barrell locks both fall into this category, as well as other more obscure mechanisms.
There are only two types of snap mechanism that I am aware of: locking and non-locking.
My personal opinion is that when used for life support, carabiners should be double locking, snaps should be locking, and both should be rated to a minimum of 22kn.
Screw gates can and are being used safely by some tree climbers and I know of at least one camp that uses some screw gate biners for its tree climbing program. They have a rigorous policy of doing a "gate check" with ALL climbers, whether they are using screw gates or double locking. They do the "gate check" before and during a program, and it ends up being part of the mindset of the climbing participants.
When I purchased my own equipment, I chose to buy double locking biners, primarily because they are faster. But I certainly would have felt OK about buying screw gate biners from a safety standpoint. I have to do a gate check with my double locking biners, anyway.
I have had a couple occurrences (years ago when double action carabiners were state of the art) when a branch rubbed against the barrel and the gate opened. It was a shocking experience to look down and see the gate open with a branch inside. This was during my tree working days, when contorted positions were common.
So should a triple action carabiner be advised for main life support? What should be said about manual screw locks? Gate Check! We still use a â€œgate checkâ€ at the TCI school so new students will look at their main tie ins from time to time.
Checking gates should always be a normal thing. No question.
Unless I can read a study that shows that screw gate biners are better than double acting I'm not going to even consider screw gates for any climber support. I have used them occasionally for hanging my portaledge. In this application the biner is hung, checked and things don't change. Much different application than in a climbing system.
I was thinking about the first auto lockers(double action) - Wales I think. The twist and push gate versus the new push button, twist, then open gate (triple action). I am not much of a fan for manual lockers now, except possibly accessory uses.
I LIKE the screw links for the new climbers, it is not something they have seen especially the deltas, so they don't mess with them. Most have seen biners and a concept hopw they work CMC rescue LIKES the screw links for the non tri-loading factor. Also the visual look at the links can be spotted like a miss tyed knot. CMC rescue only uses screw gate biners, as safety checks are DRILLED into your whole safety factor. Auto lockers I like and use but gate check-check is a must for any system no matter what you use. I have seen and thrown away both screw gate and auto lockers when they don't work right. I have seen some auto lockers not lock right so check-check is must with the also.
Psithurism - the sound of the wind rustling the leaves.
The ropes course I work on uses screw lockers almost exclusively and I hate it. We also do a very thorough check before the climbers leave the ground, but I've had campers come back down with gates unlocked! The obstacles they face on the ropes course are not much different than the branches we climb. I avoid screw lockers at all costs.
Snaphooks- yes, rec climbers use them. I use them, at least. But again, I am a tree worker/rec climber hybrid, so maybe I don't count. But they should definately be allowed, as they are quite safe.
I love language; especially tree climbing language. Can I steal that term? Maybe "climber hybrid" for short?
Those alloy locking snaps feel good in the hands and are safe. I believe the steel version is approved by the American Dental Association (smile when you throw). It is said you can cap one off if you bang your teeth. I have had that experience with a beloved alloy carabiner once.
I am just talking about the delta and oval screw links. During checks the visual of the screw collar being all the way over the threads is just another safety factor as well as the hands on.
We had one screw link get tight but a visual check showed the threads were not covered by the collar. It must have had a piece of TREE in the threads.
Psithurism - the sound of the wind rustling the leaves.
RocknRoll-Thanks for that clarification. How about this saying- "See threads- You's deads"! So here is a question along that line.
Should a wrench be used to screw down the screw link? Lock it down, so to speak. I think Sherrill catalog says do it (or is he talking about the clevis?). What do you all think about that? Has anyone seen a screw link, be it delta or oval, unscrew itself?
Should this be a usage standard? The old addage- "screw down so you don't screw up."