In reply to beardy mike:
> I hope you'd agree that if the force exerted by the sling ripping is constant (I.e. The energy required to rip it is constant) then the acceleration experienced by a lower mass object is greater than a higher mass object. It will come to rest more quickly. I.e. Time to stop is reduced. It is analogous to hitting a harder surface in the link. So yes, impact on the lower weight person is greater.
Force = mass x acceleration. Less mass at a higher acceleration can result in the same (or lower) force. So no, it isn't.
If the sling rips at a given *impact force*, then the impact force experienced by every user will be that stated figure, or less if it doesn't rip. (It has to be less, or it *would* rip).
> Because that would be an endless task. Where do you stop? A standard has been set which has been devised by people who have studied what is appropriate and that's what they adhere to. Do you question plug manufacturers how much over spec their plugs are rated to or do you accept their is a margin?
I'd question a plug manufacturer/definer of standards if the only standard was based on a 10A current (but people "know" 13A is sort of OK) when many appliances require 13A, yes.
I prefer to use climbing equipment fully within its specifications - but because of this standard I can't.
> In fact, do you ask nut manufacturers how much over the rated strength their is capable of (which would be impossible to say because it varies).
That's not the same at all, because different nuts have different stated strengths. This is a situation where a standard means that there is (until the new standard) no VF kit certified to be safe for my use, therefore unless I take an unknown risk or do a lot of pitching and annoy other users VF is effectively not for me at all. As it happens I do take the risk but I would prefer the equipment was rated for my use correctly. I'm quite big, but not excessively so.
> The standard has been written that way because they do not want misuse of equipment to occur. I.e. They don't want a child to get hold of an adult set and die, and likewise they don't want an adult to die because there are multiple standards.
Yes, I do understand. The new standard has clearly taken that line.
> No, it's not. The whole point is that you reduce the force to such a point that by the time you get to the end of the deploy, the energy has been disappated to an acceptable level so as to prevent equipment failure, even if you get a "deadstop". You will at some point stop, and that stop is never going to be smooth!
That's relying on the fact that people test over the specification with a margin, though, not on the original specification. And a totally static "dead stop", even with relatively small force, *can* cause equipment failure. Go and take some (low down) short slumps on some slings using old retired gear if you don't believe me
> Ok, so you think that you'd rather receive landing unhindered on your legs from a height of 3-4 metres (distance by the time you slide 2m which is the recommended bolt and cable install distance + lanyard length and hopefully some extension) than the disappated energy after the absorber has fully deployed of let's say 4-7kN which is a regular climbing fall... Hmm.
Who's saying I would land unhindered? The new standard does not extend the static sling parts of the equipment, it lengthens the screamer and reduces the impact force required to start it ripping. So the choice is between, with the old standard, getting a dead stop on the end of the screamer, or hitting the ledge on my feet having been decelerated by the screamer, but not quite as much so as in the former case. Yes, I would certainly prefer that scenario.
Post edited at 09:11