Type 7 vs Type 8 vs Type 13 in harness applications - is it really cost issue?

[skydiverek 55]

I noticed (in different threads and in other places on the web) that various manufacturers (or rigers) accuse others of using cheaper, weaker webbing for the harness material.

Here are some examples:

"Another example of a Wings vs Mirage container is the webbing. Mirage uses combinations of type 8 (3500 lb.) and 7 (6500 lb.) or just type 8. Wings uses type 7 all the way through. Mirage probably needs a heavier stitch count for the lighter, cheaper material used in the harness. An articulated G4 with chest rings is all type 8(3500 lb.) webbing..."
(reference: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=923738#923738)

and (from JumpShack):

"Sun Path has to use two layers of webbing to get their harnesses to work correctly, when only one layer would do the job. One layer of webbing is obviously lighter and more comfortable than two. Many Type 7-based harnesses exist as examples of a bad design which was made to work through the application of Type 8 Band-Aids. Type 13 does cost more, but cost wasn't a design consideration when we set about creating the safest harness/container system in the world. When nylon became available, cotton webbing and tapes were phased out of production. Type 13 was designed for use with the existing hardware and remains the only webbing which meets mil-spec for personnel carrying harnesses. Practically, Type 13 works with the hardware because it was designed and engineered for that exact application. We have a hard time explaining the reasons that others don't use Type 13; it appears that most Type 7 harness designs are basically copies of the early Wonder Hog design, which proved successful for the Relative Workshop. Type 13 is the obvious choice for the construction of strong and functional harnesses, but manufacturers that make copies can't always see the obvious."
(reference: http://www.jumpshack.com/default.asp?CategoryID=TECH&PageID=FAQ&SortBy=TITLE_A#7)

Two questions arrise here:

1. Is it really so important how strong the harness is, if the legstrap hardware is usually the weakest point anyways (regardles which webbing Type is used)?

2. I checked Paragear website and compared webbing prices (raw materials). Type 7 costs $1.60 per yard, Type 8 costs $1.20 per yard, and Type 13 costs $1.80 per yard. So, if you use 10 yards of webbing per rig (just an assumption), "Type 7 rig's" cost would be $16.00 (for just a webbing, $1.60 x 10), "Type 8 rig's" would be $12.00, and "Type 13 rig's" cost would be $18.00. So the cost difference is less than $10.00 per rig! Knowing that average loaded rig runs around $1800.00, would additional $10.00 make such a difference???

BTW (from Paragear's website):

- Type 7: tensile strength 6000 lbs.
- Type 8: tensile strength 4000 lbs.
- Type 13: tensile strength 7000 lbs.
- metal leg strap adapters: tensile strength 2500 lbs.

(edited typos)

[billvon 2,400]

Personally, I think the issue has far more to do with wear than with strength, and wear has a lot more to do with harness design (velcro mate locations, chafing strips, hardware geometry) than type of material. I haven't heard of harness webbing failing in a long, long time. On Bill Beaver's now-famous hard opening - hard enough to bend the harness rings - the webbing stood up just fine. (And the rings yielded but did not break, which is what you want.)

[NightJumper 0]

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1. Is it really so important how strong the harness is, if the legstrap hardware is usually the weakest point anyways (regardles which webbing Type is used)?

A couple of points:

1. Type 13 is the only type that can be used in military applications. Why? Because it is stronger, more durable and less likely to slip.

2. Type 13 does not slip as easily through the friction adaptors and therefore does not require re-tightening.

3. If you can get a stronger harness at no additional cost why wouldn't you?

Remember that the ratings are under testing conditions and not after they have been used, exposed to the environment and everything else that we put them through. Also the hardware may be the weakest link but remember stainless is rated higher and each adapter only takes half of the load on average.

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Knowing that average loaded rig runs around $1800.00, would additional $10.00 make such a difference???

Cost wise, nope. Strength, durability and slippage, yes.

[KrisFlyZ 0]

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Knowing that average loaded rig runs around $1800.00, would additional $10.00 make such a difference???

Cost wise, nope. Strength, durability and slippage, yes.

This has always bothered me. Why don't Rig manufacturers use the strongest webbing available? Since that is not what determines final rig cost anyway.

[billvon 2,400]

>3. If you can get a stronger harness at no additional cost why wouldn't you?

A harness that will hold together under forces that will kill you ten times over has no real advantage over a harness that will hold together under forces that will kill you five times over. Indeed, one could claim that you will live longer if your harness fails before it delivers a fatal deceleration load to your body. Not a big deal with harnesses, since you won't live _much_ longer. It is definitely a factor with main risers, though.

[NightJumper 0]

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A harness that will hold together under forces that will kill you ten times over has no real advantage over a harness that will hold together under forces that will kill you five times over. Indeed, one could claim that you will live longer if your harness fails before it delivers a fatal deceleration load to your body. Not a big deal with harnesses, since you won't live _much_ longer. It is definitely a factor with main risers, though.

I disagree. You are only addressing the "kill factor" vs. the durability and non-slip factor and those far out way catastrophic openings. And if given the choice, I would rather have a harness that is less likely to fail.

[riggermick 6]

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Personally, I think the issue has far more to do with wear than with strength, and wear has a lot more to do with harness design (velcro mate locations, chafing strips, hardware geometry) than type of material. I haven't heard of harness webbing failing in a long, long time.

Bills right on both counts. Harness design is a blend of function and style. A harness needs to be strong enough to withstand the riggors of it's application without exessive wear or failure. It also needs to be comfortable if the manufacturer want's it to be consumer friendly. A third point is it needs to be functional in terms of how it interacts with the other components installed on the system, such as the location and mounting of handles.

All three of these considerations must be taken into account when designing/ building a harness, if any one is overlooked the outcome could, at worst be fatal and at best a comercial flop.

As previously pointed out the "weak spot" on a harness is the hardware(provided the harness is geometricly sound and is not suffering from catastrophic design weak spot that has been overlooked). There is however another weak spot that has so far not been mentioned. The weak spot on harness webbing is the point at which the stitch pattern stops (usually a three or four point pattern). Needle holes at the tips of the stitch pattern points create a "perferation line" across the webbing.

Not to worry though, a human being would be sliced and diced through the leg straps long before the "tear on the dotted line" action happened.

So in summation; (assuming the correct hardware is present),wheather it's type eight, type seven, type thirteen or any combination of them, what really counts is how well the harness is stressed for any given load path(s) it will encounter and are the correct minimum number of stitches present to hold it together? After that it's just style, comfort and ease of use.

Just my .02c worth.

Mick.

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[KrisFlyZ 0]

Thanks Mick. That was very enlightening.

[billvon 2,400]

>Why don't Rig manufacturers use the strongest webbing available?
>Since that is not what determines final rig cost anyway.

You would not be willing to wear a harness made with the strongest webbing available (i.e doubled Type 9 or equivalent.)

[riggerrob 558]

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Personally, I think the issue has far more to do with wear than with strength, and wear has a lot more to do with harness design (velcro mate locations, chafing strips, hardware geometry) than type of material. I haven't heard of harness webbing failing in a long, long time. On Bill Beaver's now-famous hard opening - hard enough to bend the harness rings - the webbing stood up just fine. (And the rings yielded but did not break, which is what you want.)

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

While working at Rigging Innovations I rebuilt several harnesses that suffered bent hip rings similar to Bill Beaver's. All the jumpers complained of painfully hard openings. We traced the problem to a combination of ZP fabric, Spectra lines, loose Tube Stows and sloppy packing shortly after all these new materials were introduced, but before most skydivers understood the finer points of packing ZP canopies.
Yes, a few hip rings were bent. Rigging Innovations replaced those harnesses for free, then changed the production standard to stiffer, cadmium-plated rings.

[billbooth 10]

We have dropped Vectors and Javelins (which are both constructed out of type 7 and 8 webbing) on PD's instrumented drop tower, and both harnesses BEGIN to come apart at around 8,500 lbs (applied dynamically). To a 200 lb. jumper, this represents over 42 "G's", which is about twice the force required to kill a human. So, I don't lose too much sleep over the issue.

[riggermick 6]

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Thanks Mick. That was very enlightening.

Um.....thanks. By having "salt" I assume you mean experience? If so, then yes I do have some experience with the subject.

Mick.

[riggermick 6]

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Thanks Mick. That was very enlightening.

Um.....thanks. By having "salt" I assume you mean experience? If so, then yes I do have some experience with the subject.

Mick.

For some strange reason the last part of the message I was trying to quote didn't appear.

Mick.

[beej 0]

has anyone known hip rings to break - ever?

Just wonderedering..im a big guy with a new container with hip rings on order...lol

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If the shit fits - wear it (blues brothers)--

[riggermick 6]

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has anyone known hip rings to break - ever?

Just wonderedering..im a big guy with a new container with hip rings on order...lol

Nope......Never.ever ever ever. The human body is THE weak piont. fly with confidence.

Mick.

[riggerrob 558]

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has anyone known hip rings to break - ever?

Just wonderedering..im a big guy with a new container with hip rings on order...lol

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Like I said earlier, when the Flexon was first introduced, a few guys packed their Sabres sloppily enough to shred canopies and sprain necks. Even though they bent a few stainless steel hip rings, none of the rings broke. Rigging Innovations changed the (Talon 2) production standard to stiffer cadmium-plated rings and later (Voodoo era) to (flat) stainless steel RW-8 rings.
Bottom line: a few people have bent hip rings, but no-one has ever broken a hip ring. Harness webbing will fail long before hardware and the human body will fail long before webbing.

[SusanAnt 0]

As some others here have said by now, Type 13 first saw a lot of use in the military, though others had already started using the lighter Type 7. The even lighter (as much as 4,000 lb) Type 8 started being used for chest straps too. This choice came from the fact that lighter Nylon webbing than what was designed for the hardware prevented slipping and twisting. While yes, Type 13 is for those worst-case-scenario jumpers who wish to have the absolute heaviest, it's not necessary to spend the extra cash if you determine a mix of types works better for you.

[riggerrob 558]

Most MIL SPEC and PIA SPEC hardware was designed back when cotton Type 13 webbing (7,000 pound minimum breaking strength) was fashionable.
When skydiving manufacturers started offering light-weight, custom-sized harnesses, they first reduced weight by deleting most of the hardware used to adjust harnesses to fit a wide variety of sizes of military pilots. They also experimented with lighter webbing like Type 6, Type 7, Type 12 and Type 17.
Price difference between the strongest and weakest webbing is insignificant - a fraction of the cost of hardware - because labour is the largest percentage of the cost of a new harness.

The strongest: Type 13 (7,000 pound minimum breaking strength) has long been standard on Racers and Sidewinders forever ........
Recently, Strong built a bunch of Tandems with "Super 7" webbing that looked as strong as Type 13. Sigma Tandems have MLWS made of Type 17 because it is more durable when adjustable for length.

Durability is primarily a function of harness hardware geometry. For example, the top, inboard stitch on a straight harness, upper leg strap is always the most heavily-loaded and is usually the first to pop. Ergo, circa 1990, the Relative Warkshop published a Service Bulletin saying to over-sew any harnesses that did not have a double row of 5 Cord along the inboard edge. We also over-sewed a bunch of solo Vectors.

One inch wide Type 17 webbing has been limited to solo main risers, chest straps and lateral straps. 2,000 pound webbing is strong enough for chest and lateral straps because they only suffer 5 percent of opening shock. IOW chest and lateral straps only prevent a jumper from falling forward - or backwards - out of the harness and only after main lift webs and leg straps have conducted most of opening shock to the jumper.
Mike Johnston (sp?) once showed me a stack of Mirage tensile tests results comparing the strength of single-layer Type 7 webbing versus doubled Type 8. Mike concluded that Type 8 harnesses were slightly stronger because Type 7 webbing stretches more.

Trivia, when Flying High introduced RI-1 hip rings to their Sidewinder harnesses, they repeated a series of tensile tests and concluded that ringed harnesses were 15 percent stronger because leg strap webbing could pivot to the exact same angle as the load.

Similarly, Javelin harnesses with hip rings tend to wear out first at the top of the hip junction/lateral strap because that is where MLWs bend the most.

No matter what type of webbing, leg straps usually wear out first from friction caused by slowly sliding through friction-adapter hardware. A decade ago, Aerodyne published a Service Bulletin telling riggers to sew in a layer of Type 12 webbing (1,200 pound MBS) to "bulk out" leg strap buckles on Icon harnesse. Since then I have applied the Aerodyne SB to harnesses made by a dozen other manufacturers.