UKC

please. Thanks.

In reply to theswedeclimbs: Fall factor 1.77 means falling 1.77 times as far as the length of rope out. just decking on a sports route is FF=1, but falling past your belay on a multi pitch is FF2 (i.e. rope length above belay to rope length below belay. 1.77 could happen if you had clipped some distance above on a multi pitch. If you weigh more or less than 80, scale the FF accordingly. After 8 FF1.77 falls, an 80kg climber would need to replace his rope (and probably his frayed nerves)

In reply to theswedeclimbs:
The rope is put in the test rig and tested by dropping 80kg through 1.77 fall factor. The test is repeated until the rope snaps, so the number 8 means the rope survived 8 or more test falls.
8 such falls at different bits of the rope should be pretty harmless to the rope provided spare underwear is available.

In reply to md@r:


How do you get falls on different bits of the rope?

If the rope will fail, I think it would be at the knot, which is always impacted in a fall.

In reply to theswedeclimbs:
in reality a factor 1.77 is a really big fall. Most falls experienced in normal situations are probably less than 0.5 (falling 6 foot when you have 12 foot of rope out) although, there is always the risk of a big fall when setting off from belay at height so you should always look to get some gear in soon after the belay to reduce this risk.

In reply to fishy1:

In tests the rope normally falls around the 'karabiner' it is loaded over.

However you are correct that after a large number and variety of smaller falls the ends of the rope will have accumulated most damage. This is why some sport climbers progressively cut segments off the ends of their ropes to maximize use. For example, with a 70 metre rope, 5 metres can be cut off each end twice and still leave you with usable 50 metre rope.

In reply to fishy1:

In a high factor fall the bit of rope getting the most "hammering" is at the belay device or first runner which would vary depending on which end of the rope you tie into, how far the climber got, exactly where they tied in or where the first runner is on the rope. The ends of the rope wear fastest but not in a particular spot unless you make a habit of repeating high fall factors exactly in the same way.

There's stuff online about how the test is done but from memory...

...the "belayer" end is fixed (not on a normal friction belay device which slip under load), the rope passes over a 10mm diameter bar to simulate the cross section of a karibiner. The rope is 2.8m long and the fixed end (simulated belayer) is 0.3m vertically below the bar (simulated caribiner) so the 80kg mass drops 5m (2*2.5m), hence is fall factor 5/2.8=1.78.

The rope snaps where it's stretched over the bar rather than at the knot.
I think the ropes visibly degrade (blacken?) before they snap.

PS 8 such falls on different bits of the rope is pretty harmless for the rope, however 8 such falls would be pretty dangerous for the climber unless they're very lucky.

In reply to md@r: Cheers guys. So in other words. Dont worry. You will break before the rope does.

In reply to theswedeclimbs:

YES! That's a very good summary.

In reply to theswedeclimbs: There's a great explanation on fall factors (with pictures and everything!) on this website: http://www.ukclimbing.com/articles/page.php?id=647

All fall factors are based around an 80kg weight representing the average person and where based on studies by the military parachute regiments when they worked out how much the human body can take before it snaps!

In reply to Gethin Thomas: military parachute regiments when they worked out how much the human body can take before it snaps!

...and people say skydivers are nuts...'I want some volunteers for some important research...'

In reply to theswedeclimbs:


Un-damaged* ropes don't break in anything like normal use. They occasionally get cut over edges but if there's edges about you'd use two ropes.

*obvious visiable damage or corrosion/contamination
jk

In reply to jkarran:
***Highly unlikely to happen*** but a rope can be weakened to the point of failure by invisible chemical damage (eg sulphuric acid) so don't put it down in a car park that could be contaminated by battery acid.

http://www.rockandice.com/inthemag.php?id=6&type=accidents

Sorry to encourage paranoia.

In reply to theswedeclimbs:

may i add that apparently the human body wont survive an impact force of 7kn or more. massive organ haemorrage, trauma to connective tissue etc.

so no, you wont 'break' before the rope does.
you will be shaken down to blood and bone jelly instead.
nice.

In reply to ice.solo:

Apparently not.

The body can withstand up to 15G deceleration in a climbing fall before your going to start to suffer traumatic major injury. That is why the UIAA/CE standard for single ropes specifies a maximum impact force of 12kN!

In reply to Mark Stevenson:

dont tell me that!!

ive used the 7kn fallacy as an excuse for cowardice for years...

In reply to Mark Stevenson:

The trauma due to deceleration has as much to do with how it is applied to the body than the force. So a fighter pilot in a bucket seat can withstand more than a skinny man in a harness, and a alpine climber in a full-body harness padded by clothing can handle more than a skinny sport climber in a lightweight sit harness.

Then you have the reaction - an alert climber sat upright and braced will do much better than an unconscious one. 7KN could injure a knocked-out climber in a skimpy harness. The industrial standard is set at a maximum of 6KN, despite full-body harnesses being mandatory, as it is anticipated that the faller is unlikely to be braced for the impact.