The UIAA thing seems to be totally unscientific. they say that all the rope failures were caused by weighting over sharp edges and then go off about stepping on the rope with no connection to any actual tests or failures. I read tests years ago that said rapelling and lowering were the biggest culprits and a new rope with something like 10 lowering cycles had lost 40% of it's strength.
you know, the boys at REI and the other shops would laugh to see this thread. almost certainly those precious "cords o'life" are drop-kicked from the semi trailer to the warehouse pallet; and probably worse -- probably hung from the window (to show that it's an authentic "Climbing Shoppe") on a rusty nail, getting pounded by California UV day after day after day after day.
Until you -- he, who does not step on ropes -- buys it off the floor.
When I was a kid you'd get yelled at for stepping on the rope. We were climbing on goldline, which had no sheath, so you were stepping right on the core. It would also get kinda ratty after a while. I still don't step on the rope myself, just an old habit. Maybe "don't step on the rope!" is a legacy thing, might not be such an issue with kernmantle.
we had this conversation on rc years ago. tradman was there and talking about how he used the flaked rope to clean his feet at the start of climbs. then he got into how crampons wouldn't hurt the rope.
then curt stepped in, with his foot-belay photo. that was ironic, of course, but it seems that the grommie the op met took it way too literally.
rgold's sensible commentary is as out of place here as it ever was on rc.
I was lucky enough to hang out at PMI when Alan Padgett was doing research for his book, ON ROPE. He was doing destructive testing of caving ropes with various levels of sheath damage created by rubbing the rope over the edge of a carborendum stone. It was amazing how a little sheath damage could reduce the breaking stregth. Read the book if you want the actual numbers. Cavers are very careful with their ropes and they have a sheath that is designed to withstand as much abrasion as possible.
Dont step on my rope if you can avoid it.
I have some freinds who performed a more visceral test. They filled five gallon buckets with concrete and hung it from a rope. Then they took a knife to the rope. Do that a few times and you wont step on any ropes you can avoid. Just a little damage to the core is like a zipper effect when its under weight.