Petzl Anneau Polyester Slings...heat resistance vs. nylon?

Hi: Just curious if anyone knows if the Petzl Anneau polyester runner/sling is suitable for a rappel brake? Is it any more or less heat-resistant than nylon runners? Am I overthinking this?

A sling for a rappel brake ?? maybe I'm confused

yes, using a klemheist...it's my rappel brake of choice.

I'm talking about a backup to my belay device of course! :)

IMO neither will work well,,but that's just me, no one agrees with me

If you're really concerned about the heat, use a Sterling Hollow Block sling.

Thanks Gunkie...only concerned vis-a-vis nylon vs. dyneema...also flat nylon makes a nice sheath around the rope to prevent rugburn...just curious about the polyester slings since it is purportedly more heat resistant than nylon.

In truth, I cycle through these runners long before they're worn out, so the low cost of nylon is also appealing (as opposed to the hollow block).

Then again, we're talking about a backup, so the risk of catastrophic failure/melting isn't that big a deal...can I retract the question?

ebmudder wrote:Hi: Just curious if anyone knows if the Petzl Anneau polyester runner/sling is suitable for a rappel brake? Is it any more or less heat-resistant than nylon runners? Am I overthinking this?

Well they make polyester static ropes, and those see more "heat" from the rap device than a sling acting as a second hand brake ever will. Dont worry about it, you're fine. I use Dyneema slings as backups and those have a melting temp way below that of polyester.

Just make sure you're using a dedicated sling for that... heat will wear it over time... want to avoid using it for anchors // tethers during a rappel etc. I've found that when I had a sling I used this on over a period of a number of climbs the dedicated sling showed substantial damage and "looked" weaker than those used as alpine draws from the heat marks on it

Why not just buy a dedicate autoblock cord? Use 5mm and it's like $2. Way cheaper than a sling and it works better.

Hollow Block....Interesting product.

Why would one ever recommend it over ubiquitous nylon cord, though?

20kN is still alive and he's using dyneema, many other people do the same. So, IMHO nylon with a significantly higher melting point is going to be fine, too.

With a hollow block hanging off my harness, I have a new fibre that I don't know much about. I don't really understand how it ages, thus I don't know when a sensible time to retire it is. I do know that aramid doesn't last forever (check out the service lifes for kevlar vests). This is sort of an argument from ignorance, but given how surprising the DMM dyneema sling tests results were to a lot of people, I suspect the great majority of climbers don't spend much effort into learning about the properties of the fibers they're using.

Nylon's a pretty safe bet, we've all seen a lot of it, both old and new, and have a reasonable idea as a community of what a should-be-retired bit of nylon kernmantle cord looks like.

That prussik you're using as a rappel brake at the moment might only need to hold some fraction of body-weight, but as a prussik on your harness you'll end up using it for all sorts of things - like ascending, or (much much less common) to get yourself or your partner out of various SNAFU situations where it may hold a lot more than some fraction of body-weight.

I realize this style of thinking also applies to polyester, which is why we have this thread in the first place. Adding a 4th fibre to the mix of OPs rack is just going to add more question marks as to what he should use various parts of his rack for.

(I've done my climbing for the day, and there's no one awake to talk to. So I write these long posts instead :(.

Thanks for everyone's feedback...figure I'd post a few clarifications.

20 kN wrote:Why not just buy a dedicate autoblock cord? Use 5mm and it's like $2. Way cheaper than a sling and it works better.

I prefer a dedicated sling...which is ~$4...so relative cost is not an issue.

Medic741 wrote:Just make sure you're using a dedicated sling for that... heat will wear it over time... want to avoid using it for anchors // tethers during a rappel etc. I've found that when I had a sling I used this on over a period of a number of climbs the dedicated sling showed substantial damage and "looked" weaker than those used as alpine draws from the heat marks on it

That's so important I'm quoting it just to bump it in the post. I only use a dedicated sling. When it gets burned I retire it.

bevans wrote:It's generally just not "best practice" to use dyneema in high friction/heat scenarios. Can you do so? Of course. Do I? Sometimes. Are you adding hazard? Yep. Significantly? Maybe not...maybe...

Agreed...this is a dedicated sling for brake backup. I don't use the dyneema draws for this purpose.

bevans wrote:And +1 for the Hollow Block.

Hollow block does cost more, you can't configure the length, and it's as bulky as a sling. I tried it and found it to be too short, and there's only one size that I'm aware of.

r m wrote:Nylon's a pretty safe bet, we've all seen a lot of it, both old and new, and have a reasonable idea as a community of what a should-be-retired bit of nylon kernmantle cord looks like.

Same goes for nylon slings...you know when it's ready to be retired.

r m wrote:That prussik you're using as a rappel brake at the moment might only need to hold some fraction of body-weight, but as a prussik on your harness you'll end up using it for all sorts of things - like ascending, or (much much less common) to get yourself or your partner out of various SNAFU situations where it may hold a lot more than some fraction of body-weight.

That is a valid point...but it applies equally to a nylon prussik and a nylon sling.

r m wrote:Adding a 4th fibre to the mix of OPs rack is just going to add more question marks as to what he should use various parts of his rack for.

Another good point...but I (OP) only use the nylon sling for a dedicated rap backup. I use dyneema for my alpine draws, and don't use them for anything else. The one difference I can see between a sewn sling and a prussik is that you can always untie the prussik if in desperate straits.

My original question about the polyester sling was if it my be more heat resistant than nylon and hopefully last longer...the polyester slings are more expensive, so if they don't last longer, there would be no point to using it over nylon for a brake backup.

There are two lengths of Hollow Block. 13.5" and 19". The 13.5" is long enough for everything from autoblock or Klemheist hitches in rappel backups or progress capture haul systems. Some prefer the 19". Ymmv.

The hollow block usually provides greater friction than cord or slings. It is strong enough for usage as a protection sling in a pinch.

Again, use what you prefer. The point is knowing the limitations of the material you choose to use.

bevans wrote:There are two lengths of Hollow Block. 13.5" and 19". The 13.5" is long enough for everything from autoblock or Klemheist hitches in rappel backups or progress capture haul systems. Some prefer the 19". Ymmv. The hollow block usually provides greater friction than cord or slings. It is strong enough for usage as a protection sling in a pinch. Again, use what you prefer. The point is knowing the limitations of the material you choose to use.

Thanks bevans, I've only seen the shorter one, but a quick google found the longer was as well. It's about 3x the cost of a nylon sling, but it might be worth a try when I run out of slings. :)