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Fall factor


hakioawa

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While climbing some slab up in squamish this weekend, I had the opportunity to explain fall factor to a partner. Fall Factor (FF) = Length of Fall (LF) divided by Length of Rope).

 

So FF = LF/LR

 

The point of protection is to minimize FF. While leading out on a blank slab from the anchor, something occurred to me. Lets say the first piece is 30 from a bomber anchor. If I fall on a tight belay at the first piece I have a fall factor of ((30' + 30')/30') = 2. On the other hand if I have say 20 feet or slack I end up with a fall factor of ((30' + 50')/50' = 1.6.

 

So falling farther on a loose belay is better. Assuming of course I don't hit anything on the way down. Does this make sense?

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I think your calculations are off. If you fall on a tight belay (fall 3 feet with 30 ft of rope) your fall factor is 1.1. The greatest fall factor in most climbing situations is 2, unless you happen to be unlucky enough to climb above your belayer, don't put in a piece, and then fly past him. This would be a factor 2+ fall

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actually, it is possible to have a fall factor greater than 2. We have our not-so-smart leader way out there (30 feet) with no gear in. He/she falls and the eager belayer starts realing in the slack. Lets say the belayer bring in 9 feet of slack. Yeah it is alot but for this example lets just beleive this is true, OK?

Now look at the equation for fall factor. length fallen = 30+(30-9)=51 feet. length of rope out = 21 feet FF=51/21=2.43 There is your FF>2 crazy.gif

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This is not always true.

 

Example...(no or little slack)

Climbing along.

10ft above belay put in gear.

5ft above gear, fall.

 

10/15=.6666

 

Fell 10ft, double the distance above the pro.

Rope out, 15 ft, distance of climber to belay.

 

Example...(way you've been taught, say 5ft slack)

climbing along.

10ft above belay, put in gear.

5ft above gear, fall.

 

10+5/15+5=15/20=.75

 

Fell 15ft, 10ft and another 5ft in slack.

Rope out, 15ft and another 5ft slack.

 

Fall factors are different?!

Slack fall factor gets bigger with the more slack you add in!

The slack number adds to both the fall length and the rope out length. Decreasing the value of the rope distance to the pro that holds the fall.

 

Be careful, don't believe everything you read.

 

 

chris

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