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Climber injured in bluies after 30m fall 2/Jan/13 21-Jan-2013 At 10:38:34 PM Olbert

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On 21/01/2013 jrc wrote:
>I also can’t understand why you wouldn’t be able to get a fall factor above
>2 – in fact that is what looseness in a belay can do for you.

Technically looseness in the belay can increase the fall factor but only under very specific and unusual (read retarded) conditions. I'm going to skip over the fact you use the formula F_impact = mgF. I have no idea where you got this from and it is retarded. For a better approximation check this discussion on Mountain Project and also this article on Beals website.

Back to the looseness of the belay. In your scenario the belayer is clipped into the belay with a certain amount of slack which is then added to the fall length when the leader falls. You posit that this increases the fall factor. This is correct, in the manner in which you explained, if and only if the belayer was connected to the belay using a static method; if the belayer is connected using the rope then this would actually reduce the fall factor.

So if the belayer was connected with a static sling to the belay then it is most likely via a single length sling (0.6m) then it might be possible to get a FF of 2.2 with a 6.6m fall (6m till the belayer is pulled, then the extra 0.6m of slack) from 3m above the belay. However, this is really quite unlikely, as the person would have to having sex with the strong point of the anchor. Really the amount of slack would be much smaller - a conservative estimation would be half that amount in slack, resulting in a FF of 2.1 which in the real world is lost in the noise of other factors not accounted for in this over simplification.

Lets look further though - what if the numpty belayer were tied in with a double length sling. This gives the belayer a whole 1.2m of slack to play around with. Imagining this scenario now I cant think of why the belayer would have this much freedom except if they were on a ledge large enough to walk around on, if this was the case then there most likely wont be a clean fall, the leader will be hitting things on the way down. Fall factors are pointless here because the force generated in the fall isn't the problem (the climber is slowed by hitting things), its the climber hitting things that's the problem.

What about if the belayer had originally extended himself a few metres from the belay to bring up the seconder (soon to be leader, and, it seems, soon to be hurting himself) and then didn't readjust the lanyard but did reposition himself, before the leader started leading? The only reasonable way the belay can extend their belay by that much is with the rope which would reduce the fall factor - the equation would become FF = (L_fall + L_slack) / (L_rope + L_slack). Whatever the length of the fall is the addition of some slack would reduce to the fall factor to below 2.

The only scenario I can envisage of getting a decent increase in the fall factor above 2 would be if there was a belay on a reasonable size ledge (where the belayer could walk around and attach himself in with a double length sling) and the next pitch go out some sort of roof above head height (otherwise the belayer wouldn't be walking around) or traversing off over the end of the ledge (more likely). If the belayer can't see the problem of having slack in the system in this situation (even if the climber clips some pro before he falls the belayer is going to be pulled sideways) then I would be worried about a hell of a lot more than having a fall factor 2 fall. In a FF 2 fall both the belayer and climber are going to be in much pain in this situation.