Load ratings of climbing equipment?

[Mitchell]

Not trying to be a safety boss...

it will unless you do it at some weird angle
i saw a guy fall 30 feet and get stopped sharply no injuries.

Wolf, I would qualify statements like that, new or uneducated climbers can misinterpit. No one would jump off a thirty foot building into a paved parking lot with out expecting to get hurt or killed. Being stopped dead on a rope from thirty feet is the same.

If the building was over a deep pool of water that would be fun. Same with the rope; if it was a bungy cord thats fun, a steel cable your in big trouble.

I can't remeber the numbers off the top of my head but I believe just a 5 foot fall for a 180 pound guy generates in the neighbourhood of 2000lbs of force. Thats a lot of energy to absorb and if its your spine thats doing it...

I Don't like to climb more then 5 feet above my tip [10 foot fall]. A clean 10 foot fall is where forces are potentially great enouph to start breaking things [like us] in our static systems.

Have to run to work; stay safe

 

[lone wolf]

Wolf, I would qualify statements like that, new or uneducated climbers can misinterpit. No one would jump off a thirty foot building into a paved parking lot with out expecting to get hurt or killed. Being stopped dead on a rope from thirty feet is the same.

If the building was over a deep pool of water that would be fun. Same with the rope; if it was a bungy cord thats fun, a steel cable your in big trouble.

I can't remeber the numbers off the top of my head but I believe just a 5 foot fall for a 180 pound guy generates in the neighbourhood of 2000lbs of force. Thats a lot of energy to absorb and if its your spine thats doing it...

I Don't like to climb more then 5 feet above my tip [10 foot fall]. A clean 10 foot fall is where forces are potentially great enouph to start breaking things [like us] in our static systems.

Have to run to work; stay safe

ok this was not done on purpose it was a slip and a miracle I might add.

 

[pdqdl]

A 10 foot fall unto a cammed acender is a recipe for death.

In my other life as a high angle rescue guy cammed ascenders are for capturing the loads movement only, if there could be shock loading, double prussics or a device that "slips" are used. Particularly on static ropes used in rescue and tree work.

If your ascender is like mine, Its a toothed cam. Devices that do not slip under shock loading will sever the rope. A fellow around here died recently from exactly that, falling unto a gibbs ascender. Not sure how far the fall was, but apparently it was in the 10 to 15 foot range. I read of another fellow in WA state that fell 15' unto his hand acenders which severed the rope and he also died. A google search finds lots of info on this subject. I suspect your fall was not a clean fall as you would have damaged your rope at the very least.

If you doubt your TIP use a double prussic above your ascender

Something to consider: If your ascender severed the line, the prussic would likely be only a few inches above. While it would be some additional security against a fall, it wouldn't be much. 3" of slip before the rope runs out of the prussic isn't much security.

Everybody I have seen using a prussic above the ascender pushes the prussic up the line with the ascender. No real safety there!

 

[pdqdl]

Just because your equipment holds the fall safely does not mean that you don't get hurt.

I broke several short ribs once when the branch I was standing on broke off. I had anticipated that problem, and was rigged with my lanyard to the branch overhead, so no problem, right?

Nope. My lanyard was clipped to the waist-belt d-rings, which are designed to hold you against the tree. When the belt strap is lifted from an overhead attachment, the heavy fabric was lifted like powerful karate kick into my ribs, and broke several. I was VERY sore for over a month, despite the fact that I never even noticed the injury when I was in the tree.

When it happened to me, I thought how cool I must have looked when the branch fell away from me, and there I was hanging in the air, un-injured and still prepared for tree removal action. 2 hours later, it started hurting. By the end of the day, I was suffering with every breath.

That was for a 2 foot drop. 30' on a static line? OMG! :jawdrop:

 

[moray]

...Everybody I have seen using a prussic above the ascender pushes the prussic up the line with the ascender. No real safety there!

Very good point about the prusik! You really REALLY don't want to fall if a standard ascender is going to catch you. Ditto for falling on your lanyard as you have so well described.

If I had about 600 feet of static line to catch me, a 30-foot fall would be like sitting down in an overstuffed sofa. A mere 2-foot fall like yours can be much more rugged.

 

[pdqdl]

I think a 600' fall on static line would either snap the line or rip you in half.

You would certainly reach terminal velocity. At 140+ mph, I don't think 1-2% stretch of the average arborist rope would be enough to keep you from being shredded by the experience.

That crazy guy Dan Osman was falling over 1000 feet at a time, but he sure wasn't doing it on arborplex.

I really like that video that shows the dyneema line snapping in one test-drop, and the dynamic line held the same load in multiple drops, despite the fact that the dyneema line was more than twice as strong.

 

[moray]

I think a 600' fall on static line would either snap the line or rip you in half...

Of course. But a 30-ft. fall on 600 feet of rope? Soft like a bungee.

 

[jefflovstrom]

A little confusing. Are you saying that a controlled ride of 600 feet of rope or at 600 feet the rope halts you?
Jeff, CTSP

 

[Blakesmaster]

A little confusing. Are you saying that a controlled ride of 600 feet of rope or at 600 feet the rope halts you?
Jeff, CTSP

I believe he's saying a fall of 30 feet when suspended on 600 feet of rope would be nice and soft. At least that's what I gathered.

 

[jefflovstrom]

I believe he's saying a fall of 30 feet when suspended on 600 feet of rope would be nice and soft. At least that's what I gathered.

Oh, OK, Well maybe with that much rope out in play it might not mess you up too much. Still, 30 feet and then a grab, gotta be awake and prepared I think.
Jeff, CTSP

 

[jefflovstrom]

So, 600 feet of rope and a fall of 30 feet. At ground level that would be minimum 300 feet high. This is a tree thread and I guess I was thinking we dont climb 300 plus 30 feet to land on the comfy couch.
Jeff, CTSP

 

[pdqdl]

Ok, I apologize.

When I posted earlier about Dan Osman, I got to thinking about his spectacular free-fall jumps and I completely forgot about Moray's 30 foot fall restriction. Sorry about the confusion I may have introduced.

Nonetheless, I don't think falling 30 feet on a 300 feet of doubled arborist line would be any fun either. In fact, I'll bet it would hurt a whole bunch.

This is a wild guess, since I don't want to take the effort to do the math: That would be falling 10% of the rope distance into an approximate 3% stretch (assuming that you are somewhere near the 20% of breaking strength rating of the rope). Fall 30', stop in 9', putting a force of close to 3000 lbs on a doubled rope. Oooohh, my aching back!

 

[moray]

I should have picked better numbers but everyone by now is getting my point: even a very stiff rope can give you a soft landing if the fall is short compared to the length of the rope (very small fall factor). But even a very short fall can be brutal if the rope itself is very short.

I did some on-purpose jumps onto dynamic rope last year, and to make sure the landing would be extremely soft, I wanted a very small fall factor. Using 3 pulleys I managed to use about 180 ft. of rope for a 20-foot jump. The first 4 feet were free fall and the next 16 feet were rope stretch. The soft landing is quite wonderful and left me smiling all day (and gave me the tiniest glimpse of what Dan Osman must have felt). This is what I had in mind with my rather dopey example with 600 feet of static rope.

 

[jefflovstrom]

Ok, I apologize.

When I posted earlier about Dan Osman, I got to thinking about his spectacular free-fall jumps and I completely forgot about Moray's 30 foot fall restriction. Sorry about the confusion I may have introduced.

Nonetheless, I don't think falling 30 feet on a 300 feet of doubled arborist line would be any fun either. In fact, I'll bet it would hurt a whole bunch.

This is a wild guess, since I don't want to take the effort to do the math: That would be falling 10% of the rope distance into an approximate 3% stretch (assuming that you are somewhere near the 20% of breaking strength rating of the rope). Fall 30', stop in 9', putting a force of close to 3000 lbs on a doubled rope. Oooohh, my aching back!

pdqdl, we are are on the same page, I think we both know if you dont break your back on that, you are Iron Man, that is why I asked if it was a ( Controlled) fall with 600 foot of rope then the 300 foot drop at 30 foot grab is actuall a 600 foot drop with a controlled 15 foot drop ( into the comfy couch?)

Jeff, CTSP

 

[pdqdl]

Well sure that was a soft fall, Moray. That was only a 4' drop, not a 20. My little 2' drop on an 8' lanyard felt like fun too, until later that day.

I time my falls from where I begin falling to when the rope starts getting tight. What kind of rope stretches 16' in 180' on a four foot fall? Surely you are just guessing about the distances, or were you jumping on a big rubber bungie cord?

 

[moray]

No, those aren't guesses. You are right, of course, that it is really a 4-foot fall. The total energy the rope must absorb, though, is 20 ft. times your weight, and the total energy absorbed by 180 feet of rope tells you how much it will stretch. I was using a Porta Wrap for the ground anchor so that I could easily fine tune the rope length. Once the length was right the jumper could just touch a toe to the ground at the bottom of the jump.

This stuff is stretchy! If you take 80 kg (176 lb.) and hang it from 100 feet of rope, it stretches 6 feet.

 

[pdqdl]

What kind of rope is it?

I could buy a chunk of that, rig a crazy long section in a big tree, and make one heck of a children's adventure swing with it.

 

[moray]

Petzl Zephyr, 10.3 mm, static elongation 6%, dynamic 33.7%, UIAA falls 10.

 

[Mitchell]

good point

Something to consider: If your ascender severed the line, the prussic would likely be only a few inches above. While it would be some additional security against a fall, it wouldn't be much. 3" of slip before the rope runs out of the prussic isn't much security.

Everybody I have seen using a prussic above the ascender pushes the prussic up the line with the ascender. No real safety there!

The prussics would have to be a 6" inches above and dressed; which would be a pita. Better yet, lose the hand ascender and foot lock with a prussics. I have the croll ascender mid saddle which makes this fairly easy. Never tried the foot ascenders but I imagine they would make it that much easier and safe.

I have had short [3'] static falls with dorsal attachment [rear neck] on a fall restriant sytem that was eye opening but fine. I rig my prussics for ascension to my petzel mid chest attachment for this reason. Besides safety the work position / fall restriant shoulder strap saddles have eliminated heavy saw hip pain compared to the butterfly.