Effects of Chlorine on Nylon Rope

I was wondering if anyone knew if chlorine had harmful, or any, effects on nylon rope. I was thinking of getting some static line cheap but the catch is that has been exposed to small amounts of chlorine. Any comments would be appreciated.

My uneducated opinion.... run away. Chlorine is one gnarly chemical.

I was considering using the line for hauling, but, I may just suck it up and buy a new one.

Well, just go take some falls on it. If it breaks, you shouldn't buy it. If it doesn't, then you know that its safe for hauling.

Is this what your looking at?

tinyurl.com/cftwsp

Considering that swim suits are often composed of nylon and nylon blends, it seems a bit silly to worry about getting your rope wet in a pool.

[Deleted nonsense I posted further about chlorine not being bad for nylon. Yarrrrgh! 'Tis bad!]

Actually, I would retire a rope that got gasoline on it if I couldn't get the smell out, which is more an aesthetic reason. Most of my ropes don't last anyway, so it's a good excuse. But if a little gas got on the rope and it was possible to clean it, I wouldn't worry about it damaging the rope as petroleum products like it do nothing to nlyon. Some people even clean their cams in white gas, knowing it will get on the nylon sling material.

Here are a couple links to websites that list the chemical resistance of nylon - both indicate that nylon is NOT resistant to chlorine, acids, bases, phenols, and oxidizing reagents (examples of oxiding reagents are chlorine, iodine, bleach, hydrogen peroxide).
huntingdonfusion.com/downlo…
omega.com/pdf/tubing/techni…

Mulligan wrote:I was wondering if anyone knew if chlorine had harmful, or any, effects on nylon rope. I was thinking of getting some static line cheap but the catch is that has been exposed to small amounts of chlorine. Any comments would be appreciated.

Really depends on the concentration of the chlorine and how long the rope was exposed to it. Dunked in a swimming pool then rinsed off? Probably no problem. Soaked in a high concentration of bleach for a few days? Problem.

I think chlorine is used to make nylon...but...its an oxidizing agent and will "eat" (ie degrade) nylon over time too.

A small amount of highly concentrated chlorine?

Or...

A short exposure to a low concentration of chlorine?

I'd say any doubt, and, I wouldn't use a rope with exposure to chlorine.

Cheers,

-Brian in SLC

Thanks for finding those tables, Kat. It lists under chlorine (strong attack). So soaked in a solution of bleach, definitely retire the rope. I'm with you, Brian, if dunked in the pool not a big deal if thoroughly rinsed off.

Other interesting interactions:

Fluoronated Alcohols -- Severe attack
Gasoline -- Unchanged
Grease No effect

Hydrogen Peroxide 30% -- Severe effect Not recommended
Iodine -- Severe effect

Don't disinfect any wounds near your rope.

All said, I'd reject using those ropes as you have no idea what kind of exposure they really got to the chlorine and how concentrated it was.

Yay... finally a use for that forthcoming bachelor's degree in chemistry.

It really depends on the pH (acidity) of the pool, which is something you just don't know. The reference shown below indicated a 20% degradation of the amine bonds in nylon after 1 hour of immersion in water of pH 7 (neutral, common for swimming pools). How this translates into tensile strength is anyone's guess - essentially the chlorine is replacing hyrdogen* in the compounds that make up the rope.

Based on this, I'd say even one exposure could be serious - and since the chemistry involves Cl_2, which is a dissolved gas, the rope would not necessarily need to touch the water to be exposed.

Is it a death trap? Probably not, especially given the intention of using it for non-life bearing systems. Honestly, though, I'd spring for the new stuff. If you're going to lug a static line up a climb with you, it might as well be something you can trust your life to if the need arises.

www3.interscience.wiley.com…

-Chris

EDIT: Apologies for the typo. Chlorine is replacing hydrogen in the amines in the rope, not nitrogen.

A little bit about nylon and chemical bonding. In simple terms, nylon is formed by joining together a bunch of organic (carbon based) molecules with nitrogen "bridges", or amines. Each nitrogen generally accepts three other atoms to bond with - in nylon, these would be two carbon atoms, which are the ends of the organic molecules being joined, and a hydrogen atom. The chlorine attacks this hydrogen atom, replacing it because it forms a stronger bond with the nitrogen (it has a larger electronegativity, if you were wondering).

I suspect that this weakens the bonds between the organic molecules being joined. The reason is that chlorine has a very high affinity for electrons, especially compared to hydrogen. When the nitrogen is bonded with hydrogen, the hydrogen just kind of sits there and doesn't do much, but when chlorine is attached it tends to pull electrons from the other bonds (the ones holding the nylon molecules together), which weakens them.

Lastly, chlorine drastically affects the pH of water (since it forms hydrochloric acid, and hydrochlorite aka bleach). Acid is horrible for nylon - it causes a hydrolysis reaction, the exact opposite of the condensation reaction that forms nylon. Never underestimate how quickly acid can tear nylon apart.

Anyways I'll make the disclaimer that the above chemistry is very simplified, and I'm not responsible if you fail your upcoming exam.

johnL wrote:Chris, what would the effect be at between 7.2 and 7.8 on the pH? The reason I ask is that (public) pools are required to be tested and 7.0 is the rock bottom and 8.0 is the top. At either PH, the pool manager will be scrambling to fix it. Below 7 or above 8 the pool gets closed until it's within normal levels again. So realistically, a pool will have a pH of 7.2 to 7.8 and it will be tested every 2 hours to maintain this level. Hot-tubs, apartment pools, hotel pools, and high school pools, well that an entirely different story.

Less so than at 7.0. At pH over 8.0, the chlorinated water from the paper I referenced had no effect on the specific nylon being tested. And again, what they were testing was the presence of N-H bonds - I really am not sure how this exactly translates to tensile strength, except that it probably reduces it.

Anyways, I guess if it was me, and my pool, I would go ahead and use it because I know exactly how long, how much chlorine, etc. Kind of like a used car thing - I have no worries about my car with 100k+ miles on it, because I put them on it, but I'd be hesitant to buy one.

Just to point out, and not to get too geeked out by the conversation:

"chlorine" refers to many different compounds of chlorine (most common is common household bleach, which is sodium hypochlorite, which is also at a basic pH).

At any rate, I would be suspect of exposure of nylon to any compounds of chlorine, it is just not worth the risk.

It is unlikely that a climbing rope would be subjected to fluorinated alcohols under any normal circumstances. Non fluorinated alcohols, however.... ;)

Jim Matt wrote: "chlorine" refers to many different compounds of chlorine (most common is common household bleach, which is sodium hypochlorite, which is also at a basic pH).

Very true. Case-in-point: table salt.

As Brian mentioned, the concentration is the key thing. Diluted bleach is routinely used to disinfect rescue ropes from blood contamination. While some things like gasoline do not harm nylon, all the other additives that you don't know about might. And yes, I do mark the middle of ropes with Sharpies (but prefer bi-patterns).

The subject of chlorine on ropes has been of great interest lately on caving forums, since the advent of "White Nose Syndrom" in bats.

As Clyde notes, a dilute bleach solution is routinely used to clean nylon ropes contaminated with blood. PMI has an statement on their website which states:

"a mixture of 1 part household bleach (with active ingredient of Sodium hypochlorite at 5.25% concentration) with 9 parts room temperature tap water and a 10min or less exposure time, immediately followed by a thorough rinse of room temperature water will not cause any appreciable harm to nylon or polyester ropes."

HOWEVER - it appears that this statement is generally applicable for a single application. Repeated cleansings may weaken ropes. Here's a link to a more recent notice from PMI:

pmirope.com/sites/374/pics/…

It's your rope and your life - I'd be cautious.

swm

hello guys,
sorry about putting this post back to life, but i'm sure you guys could help me!

I washed all my flat (30 sq m^2) with bleach, including a part of the wall and the furnishes,
and my harness was with my quickdraws on the floor, never in direct contact with bleach or any water, but the room was really (really) saturated in bleach during 4/5 days (the windows was always opened but a calm 90°F in the day without wind didn't helped a lot. A the point it was impossible to sleep home (thanks to my girlfriend to host me during theses days.. or my thermarest camping matress in my kitchen).

the harness was on the floor with the quickdraws, with a verry thin cotton sheet on, with a part opened to room air.

It was highly concentrated bleach, and really, even my skin was suffering (altought i was the cleaning man)

basically, i'm just looking to know if an high concentration of "bleach" in the air, in a configuration like that (ventilated, but without wind, and long 4 days exposure), could go into the harness at the point to really damage it.

i saw this ( blackdiamondequipment.com/e… ) experience, they soaked a nylon harness into clorox (bleach brand in usa), 30min the harness lost 9% of strength, 72h the harness lost 73% of strength.

i really don't know, in my configuration, to what of theses two test i could compare.

in a way, at night i wasn't cleaning the flat so the air lost every night the bleach that was in the air, in an other way, maybe during 48h the harness was in contact with air "saturated in bleach". but not soaked into bleach...

what do you think? should i really buy a new harness? what about the damage it could cause to the harness?

thanks!

goofy wrote:hello guys, sorry about putting this post back to life, but i'm sure you guys could help me! I washed all my flat (30 sq m^2) with bleach, including a part of the wall and the furnishes, and my harness was with my quickdraws on the floor, never in direct contact with bleach or any water, but the room was really (really) saturated in bleach during 4/5 days (the windows was always opened but a calm 90°F in the day without wind didn't helped a lot. A the point it was impossible to sleep home (thanks to my girlfriend to host me during theses days.. or my thermarest camping matress in my kitchen). the harness was on the floor with the quickdraws, with a verry thin cotton sheet on, with a part opened to room air. It was highly concentrated bleach, and really, even my skin was suffering (altought i was the cleaning man) basically, i'm just looking to know if an high concentration of "bleach" in the air, in a configuration like that (ventilated, but without wind, and long 4 days exposure), could go into the harness at the point to really damage it. i saw this ( blackdiamondequipment.com/e… ) experience, they soaked a nylon harness into clorox (bleach brand in usa), 30min the harness lost 9% of strength, 72h the harness lost 73% of strength. i really don't know, in my configuration, to what of theses two test i could compare. in a way, at night i wasn't cleaning the flat so the air lost every night the bleach that was in the air, in an other way, maybe during 48h the harness was in contact with air "saturated in bleach". but not soaked into bleach... what do you think? should i really buy a new harness? what about the damage it could cause to the harness? thanks!

In this particular case, I'd be paranoid enough to buy a new harness. As you found, bleach and nylon don't play well together at all.

Let's set all safety concerns aside. Think of yourself using these items on a future climb. Now ask yourself if you think you will be concerned about the chlorine exposure while trying to concentrate on the crux.

Dustin Stotser wrote:Let's set all safety concerns aside. Think of yourself using these items on a future climb. Now ask yourself if you think you will be concerned about the chlorine exposure while trying to concentrate on the crux.

Exactly. I would trash it. Harnesses are not that expensive.

harness 100$
11 quickdraw 115$
+sling..