Sunday, September 20, 2015

The Curious Case of the Commercial Umbilical Strengths?

Better said, "Who knows what they will actually hold?"



I guess I am not surprised when I look at the inability of Petzl to have aconsistentumbilical attachment point incorporated into all their technicaltools. Whilein comparison,BDbuilds and then load tests theirs to 1500# or better. Of course neither theirumbilical or anyone leashes will take 1500#. Grivel?They want you totie into a plastic part on some of their tools! The rest of the tool business? It isno better or worse.



Just a small case study of the extremes in the ice climbing equipment world.



Why we as a climbing communityput up with this kind of nonsense is truly stupefyinghowever.



From Left to right:

BD Sprinner leash, old style Grivel Spring leash and a Metolius FS Mini Wiregate









BD flat steel mini biner is good for 1500# or more but 2Kn (450#) rated by the UIAA tag on 13mm (1/2"?) tube webbing. (1/2" nylon tube was rated @ 1800# in the old Chouinard catalog)



Th nylon webbing is likely to always be the weak link on any umbilical.



2kn is the UIAA requirement for leashes. What the hell are they thinking when they write that kind of requirement when it gets applied to umbilicals?



Black Diamond sez:



"Just tested this to 800lbs (single leg of the Spinner leash). No damage to the 4mm cord or our steel clip (production quality with more tumbling to the part); the bungee webbing breaks first. Then pull tested our steel biner clipped to 5mm cord, this went to 1600lbs before the cord broke."



More? This after my earlier comments about umbilicals "being fashionable" and not being designed specifically for the use.



"The steel clip on the spinner leash is anything but fashionable. If I made it out of aluminum it would be a lot lighter and weaker (hence more fashionable), and if I made the gate opening smaller and the gate shorter, it would be a lot stiffer for a given diameter of wire. The strength of that clip is somewhere north of 3000lbs (I don't know how strong it really is because everything I have tested it with broke first) ."



Of course no accounting for the fact that the BD Spinner leashes have the nasty and well know habit of popping off at any given moment.



Grivel flat aluminum biner is stamped "3Kn" (675#) on 16mm (9/16"?) tube webbing (9/16" tube was rated @ 2800# in the old Chouinard catalog)



I've no clue what the Grivel is actually good tostrength wise. But the same binerwas soldas a key chain holder. I have blown the sheath on 4mm cord connecting a single side strand of the Grivel. Biner and webbing seem unharmed. So better than the 3Kn that is stamped in the Grivel biner I suspect. Grivel went to a mini locking boner early on. They might be on to something since Grivel was the first company to offer a commercial umbilical.



Metolius FS Mini Wiregatebiner is engraved is 22Kn (4950#) and a good bit heavier and bigger physically in every way as well.



By the "feel" of it the original Grivel wire gate biner (2.5mm wire) has at least twice the gate opening resistance as the BD (2.4mm wire) and easily 3 times the opening resistance of the Metolius mini biner (2.2mm wire).



Some of thisgoes right along with plastic racking biners (that break or open consistently enough todrop racks)and umbilicals that areonly requiredto take a 450# load by the UIAA requirement. That as we all know, on occasion, are required to catch full size falling bodies. What the hell isthe UIAAthinking?How about a designand strength requirements that incorporates the actual use?



Umbilicals have been in use at least 30 years now in the ice climbing community. This isn't a new idea or use.Umbilicals were pullingthe spikes through water rotted laminated bamboo on Chouinard Zeros back then. May be it is about time the rest of the world catches up with what we actually do require.

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