Falling on an ascender and rope failure

[David Humphries]

Simply trailing a second line after the first in the direction that you have thrown will keep your bomb point and negate the cluttery ones. Helps in not having the rope jam on the cluttery ones too. !

 

Konnichiwa Paul

 

"Bomb point".....Que?

 

 

help out a weary old tree clamberer.....please

 

 

 

 

.

[Marc]

One of the lads that works with told me that a drop of 1 or 2 meters on an ascender could snap your rope. He didn't seem certain and couldn't tell me where he got this info so I thought I'd ask on here.

 

The situation I'm considering is when you've pulled your line through the back of the tree and you got it through a good crotch at the top, but it's passing over smaller branches which could snap.

 

I was thinking kermantle rope should be ok as the strength is in the core, but maybe not on arborist line.

 

Any body know the truth?

 

Thanks.

 

What is the rating of a toothed ascendor? And have you read the leaflet that came with it? Just curious.

 

I have been using toothed ascendors on kernmantle rope for many years as my daily access method without any problems, it is a safe and efficient method to use when properly set-up.

 

It is scary though seeing guys use ascendors as life support, I even saw one climber on SRT work positioning with a wrench using a natural redirect pre tension his line with a toothed ascendor and a 3 way pulley set-up, so his primary support became a tensioned ascendor.

[carlos]

hi arbor jeasus,

i have had a drop on single line because of a small branch snapping, no damage to the rope but deffinatly didnt feel good for the gear or me!!, so now i always spend a minite having a good look at the route of the rope and most importantly get two of you on the rope to give it a good test.

also love not having to isolate the branch, a real bonus with my throwline skills.

[Al North]

Hello,

 

I'm new to the forum but have a background in rope rescue and caving so this post caught my eye as it is a common discussion within rope rescue.

 

A Petzl Basic (or Ascension) will potentially cause damage to the sheath of a 10 or 11mm static kernmantle rope at a static load of about 550kg - 600kg. This sort of load can of course be achieved dynamically if slack is introduced into the system and then fall takes place. The other thing to consider is that human body is the softest part of the whole system and a 550kg load applied to you would be very uncomfortable!

[Marc]

Hello,

 

I'm new to the forum but have a background in rope rescue and caving so this post caught my eye as it is a common discussion within rope rescue.

 

A Petzl Basic (or Ascension) will potentially cause damage to the sheath of a 10 or 11mm static kernmantle rope at a static load of about 550kg - 600kg. This sort of load can of course be achieved dynamically if slack is introduced into the system and then fall takes place. The other thing to consider is that human body is the softest part of the whole system and a 550kg load applied to you would be very uncomfortable!

 

A few things, firstly clarify Static rope we talking typical static line like the classic Beal antipodes or dyneema zero stretch lines, if not what would the difference be if any?

You say 550kg before failure occurs so this makes for argument sake a load rating 5.5kn it could be slightly lower, I,ve heard of failures at 4kn.

Again how does line affect this figure, and how do different lines react like double braid, kernmantle, and unicore where the outer and inner are woven together. I've also know of certain ascendors failing at the cam if the rope does not tear/fail after all they are not designed for excessive load so something has to give.

[softbankhawks]

Hi Mark, long time no speak, how are you? Al North welcome to the forum. It's great to have input from other industries. I agree with Mark that a well set and anchored kern mantle/tooth ascender system has few flaws, and seeing that the climber is only able to ascend and then swap to a work positioning system there is very little chance of slack being introduced through the ascent climb. I don't agree that is is suitable for what an arborist has to do (up-down-in-out movement)but that is my opinion and I choose my system accordingly.

Miss-use is easy to apply with any system and I wish that training bodies within arboriculture would address single and double leg ascent technicalities. Addressing remote high-point anchor setting is needed too.

Mark, can you explain again about the strange pre-tensioning thing, why did he feel the need to do that?!

I'm running an SRT workshop this weekend if anybody would like to come to Japan!

[softbankhawks]

Mr Dave, otsukaresamadeshita, Bomb as in Bomb Proof!

[Ian88]

I remember from my IRATA training that a toothed ascender can start to strip a rope from 4kn - 400kg.

[Al North]

A few things, firstly clarify Static rope we talking typical static line like the classic Beal antipodes or dyneema zero stretch lines, if not what would the difference be if any?

You say 550kg before failure occurs so this makes for argument sake a load rating 5.5kn it could be slightly lower, I,ve heard of failures at 4kn.

Again how does line affect this figure, and how do different lines react like double braid, kernmantle, and unicore where the outer and inner are woven together. I've also know of certain ascendors failing at the cam if the rope does not tear/fail after all they are not designed for excessive load so something has to give.

 

By static I mean rope to the European standards (more correctly called semi-static) - it still has a low percentage of stretch. North American standard static has virtually no stretch at all (true static). Some UK rescue teams are now importing North American standard ropes as it makes hauling systems more efficient but you have to take the different characteristics into consideration.

Dyneema is excellent in the strength stakes but as it has no discernible stretch it has the potential to generate much greater shock loads if used incorrectly. I attended a rescue rigging course a few years back run by a Canadian specialist and was pulled up on my use of a dyneema daisychain sling as a cowstail - a practice common among uk rock climbers. A quick run through the maths showed that if I took a fall from above my anchor point the dyneema would not break but my pelvis possibly would!

I too have heard of failures at about 4kN but for the Petzl Basic etc these would occur on smaller diameter ropes (say 9mm). Not common in Arb work I would think but for cavers carrying hundreds of metres of rope underground - bulk and weight is important.

I only have experience of kernmantle type ropes so can't comment on the others.

I know that items like a Petzl Croll can fail at the cam if used in hauling systems as they are not designed for this type of use. The length of the channel is not as long as on the Basic or Handled Ascender.

Thanks for the welcome anyway guys - I'm keen to learn all I can about other arb climbing techniques as it can only enhance what we do and on a good day practicing in a tree is infinitely better than down an old mine shaft!

[softbankhawks]

I'm sorry if this bores you to death but it is relevant to this thread. I made it as a guide for those wanting to set-up arborist single line work positioning or ascent systems.