Random riser and webbing tests

[KellyF 16]

I had several sets of risers and pieces of harnesses that we had replaced littering my office, so I decided to pull test them and put together a non-scientific presentation for last August's PIA meeting in Portsmouth, VA. The jump numbers are estimates only, the main idea was to give people an idea of strength degradation due to various levels of wear and tear.

We don't know exactly what caused the heavy fading on one harness, but it was likely some form of acid.

The complete harness that is shown towards the end was subjected to repeated zig-zag passes with a dull needle at all the typical places where it is sewn to the container and legpads. The butterflied sections at the rings were left original.

For reference, Ty-7 webbing is rated at 6000 lbs., Ty-8 is rated at 4000 lbs., and Ty-17 is rated at 2500 lbs. We typically see a Ty-17 riser break at around 3400 lbs.

I'll try to answer questions, but I'm pretty busy lately coordinating our upcoming move, in addition to the standard day to day fires that need my attention
Here's the link to the dropbox file:
https://www.dropbox.com/sh/ilczfkhabvzeb3w/AACBYR5Rz60ApRCSBmyEbCc1a?dl=0

[pchapman 261]

Cool, the fun things one can do with some used gear and a big pull testing machine! As a rigger I have almost no stuff like this saved on my computer except the Wilcox webbing tests published many years back.

My thoughts:
(After looking thru all the pics, trying to do a reasonable job of analysis, but without very careful comparison. Anyone feel free to do a better job of it.)

Doing a bunch of tests on different risers really showed how much variation there is. One could still see trends, like mini risers with 'normal wear and scuffing' breaking at 3300lb and more. While heavier worn ones with actual broken strand fluff near where webbing loops around rings, breaking down to 2500lb. The damage in those cases didn't always look that terrible but decreased strength a fair bit -- Reminds me of what one gets with edge damage on lift or leg webbing.

(Of course there's a lot of subjectivity about what minor vs. heavy wear is, when many of us don't have a feel for what actual strength losses occur.)

It can still be debated, what the effect is on use in the field, if a riser's strength decreases to 2500 lb compared to an original 3400 lb or so.

Risers in the tests didn't always break at the point of most noticeable wear, with no really clear patterns seen at first glance.

Still, modern risers (at least as VSE builds 'em) don't break at the grommet hole (only saw that once in the dozen odd tests), but typically in the webbing by the small ring or the big ring or some combination. (I didn't try to analyze the exact sequences carefully.)

The type 2A loops, even when somewhat worn a little, weren't breaking, which is nice. That loop, while still rather important, is one that easily gets some wear relative to its small size.

As for leg straps and MLW's etc.:

Edge cuts are nasty as we've been told. (eg Ty 8 lateral failed at ~1800 lbs vs. 4000 spec)

Fuzzing at the edges, while one does see quite a bit in the field at times, can have a big effect. (Some edge fuzzed type 7 leg straps failed at slightly under 50% of their rated strength.) I'm not sure we always like to admit that out in the field.

Strong acid kills nylon, as we know.

Thanks to VSE for being willing to show off their stuff, all worn and ripped up!

[jerolim 7]

Please, if you have opportunity, test legstrap slippage with flip flop friction adapters (with ty-7 and ty-8).

[hackish 8]

Awesome tests! As someone who builds a lot of risers, I love seeing stuff like this. It really highlights the need to be picky about retiring worn parts and for those who construct, to make sure they are built to a high standard.

The scary one was the red reserve risers breaking under 1000lb.

Do you know what the typical riser load is for a terminal opening?

-Michael

[KellyF 16]

jerolim

Please, if you have opportunity, test legstrap slippage with flip flop friction adapters (with ty-7 and ty-8).

Ty Bowen and I did some tests years ago with the two piece hardware and more traditional hardware. I don't think the two piece was assembled they way they typically are now.

We tested a couple of different colors of webbing that had varying levels of stiffness, both clean and contaminated with fine dirt. The takeaway was that hardware that had some knurling on the bar held more consistently than than the two piece that didn't have any knurling.

hackish

Awesome tests! As someone who builds a lot of risers, I love seeing stuff like this. It really highlights the need to be picky about retiring worn parts and for those who construct, to make sure they are built to a high standard.

The scary one was the red reserve risers breaking under 1000lb.

Do you know what the typical riser load is for a terminal opening?

-Michael

Thanks! I hope this can help people determine (with risers, anyway) what is worthy of immediate grounding, vs. something that is worthy of replacement, but can be jumped for the rest of the weekend and a replacement ordered on Monday, for example.

Those "red" reserve risers left the factory as black

I don't have data for loads for an average main deployment, but we measured up to 3700 lbs. on each side of the harness at 200 knots with 360 lbs. in the harness. When you think about a 200 lb. jumper (easy math), even the weakest risers in the test would likely withstand a 10g opening (all on one side, even).

I'm not trying to advocate people jump beat up, worn out equipment, just that a couple of broken fibers here and there generally isn't cause for concern. Inspect your gear, and observe the wear characteristics

[RiggerLee 61]

These are some of the most interesting studies.

The complementary question in all of this is how strong do we want things to be? There was a time when I thought that the goal was to build things that would never break and last forever. Over the years I've seen a number of people injured by hard openings, think internal injuries or paralyzed, and even some people killed. I've seen several risers break. Looking back on it I wonder if they were lucky. At some point, some thing is going to fail. I'm starting to think that I don't want my body to be the weak point in the chain.

Lee

Lee
[email protected]
www.velocitysportswear.com