UKC

Hi All, a question for the chemists out there. Can cat pee damage ropes? Sounds ridiculous, and dog pee must be safe enough given the number of crag dogs that have peed on my rope bag over the years, but I remember reading on here about gear needing to be retired due to exposure to a surprising range of everyday household solvents etc. And the pee of this particular old cat smells like it could put a hole in the hull of the Nostromo. 

Many thanks, and apologies in advance for any delayed replies, limited internet access here.

There was this thread

https://www.ukclimbing.com/forums/gear/effect_of_urine_on_harnesses_ropes-5...

As a chemist at a guess I would say, no, cat pee won't damage your ropes. It contains amino acids and not strong mineral acids which probably would damage your rope.

Just wash the smell off and go climbing - I would. 

UIAA says it doesn't affect ropes see,

https://www.theuiaa.org/documents/safety/UIAA_NFK_SHARPEDGES_2025_ENG.pdf 

How knot 2 (on YouTube) recently did a video about sun bloc on ropes (spoiler: turns out the UIAA are somewhat adrift on this); maybe someone could persuade him to do one on pee? No doubt an amusing topic although pee is surprisingly benign stuff when fresh so probably no major surprises.

As a chemist... What's the take on ammonia/urea and nylon (polyamide)? That's my concern for urine, not any acids

Do you have a concern for Harris Tweed as well then? :-}

Yes, for safety any Harris Tweed jackets MUST have leather elbow patches or they're not UIAA standard

you can use compatibility charts to get an idea if there's a fundamental chemical thing going on, there's plenty of them out there: herte's just one: https://www.calpaclab.com/nylon-chemical-compatibility-chart/

I'm not a chemist so can't give you any advice on all the different ammoniums, or a urin analysis. but piss tends to stink after short period of time, I think it's some urea degredation that produces the ammonia. best to rinse it off asap. 

I'd go as far as to say if your, or your cat's, piss contains any of the compounds marked "D" on this chart - seek medical advice! 

I don’t think you need to understand chemistry to answer this question, just cat psychology. A cat would only choose to piss on your ropes if it knew it was going to damage them. 

So, the UIAA said that there are a lot of different chemicals in different sunscreens and insect repellents, some of which are know to attack plastics (the insect repellent used by the British Army attacked the rubber cup on the sights of the SA80 assault rifle when it was first released), therefore they said that in the absence of any testing and with the great variability of chemicals in these products, probably a good idea to keep them away from ropes.  https://www.theuiaa.org/uiaa-safecom-answers-your-questions-suncream-and-cl... 

How Knot 2 tested 8 sunscreens and found that the ropes soaked in sunscreen didn't fail below the strength of the control specimen.   youtube.com/watch?v=R44CWWezq0o&  which is reassuring, but there's still a lot of other sunscreens and insect repellents out there.