A couple of us got into this discussion just the other weekend, in fact. I think the concensus was that, while the improvement in breaking strength is debatable (I've heard that non-integrity risers tend to break well away from the grommet), there's something to be said for keeping the delicate bits of the mechanism (i.e., the little white loop) hidden behind a beefy chunk of webbing. Especially in a BASE environment, where crawling around on the structure is sometimes the order of the day.
Hi Tom, Please Explain what you mean by "integrity" and "non". I am aware of differing types of integrity that you could be considering but not sure which one, Integral with the Harness (meaning no 3 ring?),
or reversed risers?
Thanks,
take care,
space..
like the old saying goes.
'IF AINT BROKE, DON'T FIX IT."
I tend to believe that if Bill Boothe wanted integrity risers, he would have invented them that way. it sure looks like a awful lot more stress is put on the little white loop with integrity than not. just my opinion.
I am referring to the "reverse" style risers. Standard three ring, but reversed so that there is no hole through the riser itself.
Here's a more complete explanation:
Standard, non-integrity risers, are similar to the style used in skydiving. Usually built from Type 8 (wide) webbing for BASE use, non-integrity risers use a grommet in a hole through the riser to guide the final loop from the three ring assembly throught the cutaway cable. The cable is housed on the rear side of the riser. [This contrasts with an integrity riser, which has a "reversed" three ring assembly, so that there is no hole or grommet through the riser itself.]
The reverse risers are technically called "Integrity Risers." BR and CR make this style standard. Morpheous and Paratech will make them as a special order by customer request.
Gravity Sports, Vertigo, Morpheous and Paratech ship non-integrity (Skydiving Standard) risers as their standard. BR will make them as a special order by customer request.
There are other minor differences between all of these risers, and some major differences, particularly in the GS and Vertigo risers (which use a steel toggle pin instead of a cloth toggle stub).
I prefer Integrity style risers (in fact, I will only jump them).
I wanted to see what other people thought.
--Tom Aiello
tbaiello@ucdavis.edu
P.S. Sorry if I'm getting the terminology wrong. Can someone correct me?
P.P.S. Does anyone have any information on riser failure and wear points? I've heard the argument that the hole and grommet aren't the weakest link, so they are ok. Anyone care to elaborate that position?
Hi Tom,
All of the failed risers I have seen were mini ring, Type 8 and 17, though only one type 8. One set of failed reversed mini´s I inspected (as a rigger) had the loops sewn 3mm too short, which lead to an overlaod. So basicly, Mini rings are the prob, The tolerances are quite small, a correct design is engineered so that the components stretch into proper alignment. So the parallel plane of the rings check does not apply.
A well known rig designer who was doing a report of failed mini risers changed the title of the report to failed mini ring risers after seeing the type 8 that failed.
alignment vs geometry.
If all is correct in an Old style 3 ring system, supposedly upon loading, you would get a reduction of force @10/10/2. example; 1500lbs load Harness ring=150lbs middle ring webbing load, 15lbs small ring webbing load, and loop load of 7.5lbs. But if for instance the small ring webbing had elongated, The Reduction of force would give a 10/2/2. Meaning 1500lbs would be reduced to 150, 75, 37.5lbs at the loop. 4.5 X the stress it was designed for.
Mini ring systems have not a 10/10/2 reduction. I would guess that they have a 6/6/2 (900/90/45) if properly designed and loaded. Add an elongated small ring webbing and you would get a loop loading of 225lbs if my guess is correct.
The failure points I have seen are the loop, the small ring webbing, and the middle ring webbing.
I hope this helps, My opinion states that mini ring systems are only beneficial cosmetically, Reversed risers are psychologically more appealing and easier to build but are equal to Normal type. Mini risers suck, mini 3 ring sys suck less, mini ring riser (type 8) on a big ring is acceptable for me.
Take care, Feel free to to point out any uncorrect thingies..
space
Thanks for the elaboration! As I mentioned, I've heard that non-integrity risers don't usually fail around the grommet, but couldn't figure where else they would fail. Your reasoning and experience is very helpful on that one...
Also recall Integrity risers only came about because Type-17 (Mini Risers) were failing both on the DZ and on a few BASE jumps (ie, the "Pick" whistling in off Half Dome).
Many of these failed around the grommet (because once you punch a hole and place the grommet in a one inch riser there isn't much riser left over).
The fix was reinforcing the bottom end of the riser but the newer Integrity Risers are better not because they are reversed, but because you don't have to punch a hole in them for a grommet.
However, the major draw back is Mini-risers themselves. The individual legs are only rated at about 2500 pounds. Poynter says (and I think I've felt a few on them) that opening shock can sometimes exceed ten Gs (for a nano second or two anyway). So using them on BASE jumps calls for the utmost in care, inspection and a set of balls that clank.
I also believe Bill Booth called Mine Risers a fuseable link so that your harness won't fail which in BASE jumping is seldom of any solace except for resale.
Type Eight legs are something like 6000 pounds.
Watch it . . .
BTW, the slider hanging up on the riser saved the Pick.
Nick
BASE 194 :P
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