5mm cord, Is it safe for anchor setups?

Is this stuff good enough for anchors? Its rated for 1,600 lbs, A guy that I climb with says its really unsafe. I got it at REI not to long ago? Is anybody else useing it too.

Safe is a relative term. Personally I use 7mm. I think the only 5mm stuff that you're "supposed" to be able to use is the stuff with spectra/dyneema in it but I'm not a fan of how slippery it is when tying knots in it. Plus if you're using it for weight savings I think it's a little ridiculous unless you're pushing the current grade limits in trad climbing. If you want to save weight go on a diet ;)

Thanks man, Just looking for more opinions on this stuff. Another guy that I climbed the nose with said it was fine, So we used it.

Pizmoe wrote:Thanks man, Just looking for more opinions on this stuff. Another guy that I climbed the nose with said it was fine, So we used it.

Sure, this is the stuff I was talking about:

http://www.bluewaterropes.com/home/productsinfo.asp?Channel=Occupation&Group=&GroupKey=&Category=Accessory%20Cord&CategoryKey=&ProdKey=178

Doesn't sound like it's what you're using though because this stuff is nearly twice as strong.

If it's 5mm assessory cord don't build an anchor with it. A factor 2 fall for a 80kg climber (176 lbs) generates about 9 kN which is 2,023 lbs far exceeding the 1,600 (7.1kN) rating of the cord you mentioned. Most rope manufactures will say somewhere on the product or their website that 5mm is for non-life safety applications (sterling has this on 5mm cord description).

Do you build anchors with single strands of cord, Matt? If not, you might want to rethink those numbers. That's not to say I don't agree with you, just that you've forgotten to take into account that the arms of the anchor are typically loops.

Matt Marino wrote:If it's 5mm assessory cord don't build an anchor with it. A factor 2 fall for a 80kg climber (176 lbs) generates about 9 kN which is 2,023 lbs far exceeding the 1,600 (7.1kN) rating of the cord you mentioned. Most rope manufactures will say somewhere on the product or their website that 5mm is for non-life safety applications (sterling has this on 5mm cord description).

Assuming that you somehow built an anchor which put all of the weight on a single unknotted strand. Most people double the load rating and subtract a bit for knots when using material for anchors because you should always have at least two strands taking whatever the load is.

I use 5.5mm Titan (Tech) cord when I bother to carry cord for anchors (usually only when I know that I will be leading all the pitches). It is plenty strong. The loop strength (~26 kN) probably exceeds the major axis strength of your belay carabiner (~22 kN).

Edit:
According to the BlueWater website posted by Nick, above, 5.5mm Titan cord (~13.7 kN) is stronger than 7mm accessory cord (~10.4 kN).

Pizmoe wrote: A guy that I climb with says its really unsafe.

It's unsafe.

I have no evidence to back this up, but i feel like a thinner cord would be more prone to cutting. Where i climb rockfall is always a concern.

I think it depends on exactly how it's being used. For a toprope anchor with three equalized, solid pieces I'd feel fine.

Assuming a knot efficiency of 50% (very conservative) a three-point equalized anchor should give you 4800lbs (21kN) not accounting for angles and friction. That's quite adequate, but doesn't offer much of a safety margin if it's not well equalized or if a piece fails.

In situations where you're likely to subject the anchor to a significant shock load (trad), particularly if you can't ensure a reasonable degree of equalization or if some of your pieces are iffy, I would go with larger diameter cord for the increased safety margin.

I probably wouldn't go with less than three points on 5mm cord without doubling it up, but I don't think it's necessarily "really unsafe" to use it.

priapism wrote: It's unsafe.

Its interesting how one guy would be ok to get on el cap with it, and the other guy doesnt like top roping with it.

Pizmoe wrote: Its interesting how one guy would be ok to get on el cap with it, and the other guy doensnt like top roping with it.

I'd be more worried about building a top rope anchor with it than leading from it. Cord that thin doesn't have a super durable sheath and I'd be more worried about abrasion with it unless you're top roping a perfectly vertical crack.

Just my $0.02

Rethinking my original statement for shits and giggles I just ordered some up. I've never owned it only messed around with someone else's. I'll probably make an ACR out of it and mess with it next week when I go to Boulder. I'm assuming it will pack down nice and tiny, since I'll most likely be doing all of the leading I can rack on my harness and this shouldn't take up too much room.

I usually use the rope but when I carry a cordelette it's a 7mm nylon chord. I suppose you could use spectra/dyneema and a thinner cord but I've never enjoyed tying knots in that stuff. I don't think I'd want to use a 5 mil nylon cord for an anchor and I don't think it's designed for that.

Typically I use 5 mm cord for a prusik or anything that will take a static load only. Like the attachment cord for a haul bag for example.

But an anchor should be beefy, and able to withstand a catastrophic event such as a big factor two fall. For this I think you need AT LEAST 6 mil and preferably 7. The anchor is the only thing keeping you and your partner from going splat.

This is precisely why I like to use the rope. It's dynamic, and it is designed to catch giant falls and withstand huge forces. Why not use the strongest piece of gear you own for your anchor?

Nick Mardirosian wrote: I'd be more worried about building a top rope anchor with it than leading from it. Cord that thin doesn't have a super durable sheath and I'd be more worried about abrasion with it unless you're top roping a perfectly vertical crack. Just my $0.02 .

there was no abrasion, he followed me up, I belayed from top, same difference as a top rope I think?

What's your life worth ?
If it's an ounce or two, then risk the 5 mm.

Paul Davidson wrote:What's your life worth ? If it's an ounce or two, then risk the 5 mm.

+1

For single pitch top-roping I would agree that a 5mil line is strong enough to hold the force but probably not capable of withstanding major abrasion. As for multi-pitch TR set-ups where you will be bringing up one second it seems fine to me, of course I would make sure it is some sort of maxim line which is tested to particularly high forces (for 5mil lines).

Jon Marek wrote:For single pitch top-roping I would agree that a 5mil line is strong enough to hold the force but probably not capable of withstanding major abrasion. As for multi-pitch TR set-ups where you will be bringing up one second it seems fine to me, of course I would make sure it is some sort of maxim line which is tested to particularly high forces (for 5mil lines).

+1

I actually use 8mm cord for top rope anchors, not because I don't think thinner cords won't hold the forces but because top roping can abrade the sh#t out of cord and ropes. For multipitch I use dyneema

Paul Davidson wrote:What's your life worth ? If it's an ounce or two, then risk the 5 mm.

+1
I never thought of it like that, I think ill keep using it, thanks.

Just finished Climbing Anchors second edition and it really made me rethink using static chord like 5mm dyema or similar. The book made a case that the flexibility of nylon decreases peak forces while static chord just transfers it. Would highly recommend the book to anyone who climbs gear, it made me change some of my go-to setups.