Anyone using the HANS device?

[gbaker]

Originally posted by JackOlsen
I hadn't thought about that aspect of it. Is the idea that the truss would have to be remvoved before you could get the neck immobilized on a backboard?

Jack,

People are just beginning to work on this. The basic issue is being able to extricate the driver with a minimum of motion/load to the spine, in order to avoid paralysis.

James knows more about this than I do, but I understand the general protocol is to place a backboard between the driver and the seat back before the driver is moved. This is made more difficult by the presence of head surrounds. We have been told (emphasize secondhand info) that the HANS device can present a problem because, in order to remove it, the EMS crew needs to move the head forward, which they are loath to do. I'm not sure why the HANS could not be left in place, but maybe James has could chime in.

See the underlined sentence in the fourth paragraph here: http://www.rsisafety.com/

[jpachard]

So, When I was working EMS the goal was to get a backboard behind the patient while they were still in the car. This was done if the car was safe ie. no fires etc. Usually we had one person behind the victim to stabalize the neck until the board could be inserted. After that, it was pretty straightforward thought sometimes we would remove the roof if nessessary. One solution I have thought of is to remove the race car driver by taking out the seat with the driver in it. It's a great backboard if still intact and could make the whole operation much quicker and easier. As I said before, every situation is different and some procedures vary from state to state.

Cheers, James

[lateapex911]

This is one of the most interesting threads on the subject I've read.

I too faced the same questions and concerns, and last winter, made my decision. I've raced with an H & N system for a year now, and I'll add my thoughts to the data set here, maybe it will help answer some questions.

I read the papers and studied the test results, and it was obvious that the "Big Two" were HANS and Isaac. But, completely different methods to the same goal: hydraulic vs webbing.

I boiled the decision into three areas: Protection, Ingress/egress, and Comfort.

Protection . Really, it's a wash numbers-wise. But the Isaac looks to have significant advantages in off axis incidents due to its design. Of course, this is untested and just an off the cuff opinion. But the fact that the HANS is a strapped based system means future degredation of the straps, requiring replacement every two years, if you are to follow the recent standards. And most importantly, the HAS is dependant on prober adjustment, and the tighter the better, which affects......

Ingress/Egress: A tightly adjusted HANS is more effective than a loosely adjusted HANS. But also more restrictive. I was concerned about that, and felt the Isaac held an advantage here due to it's basic premise, which is that the shocks are loose until the velocity of an impact causes them to go stiff. (And that seems to me to be a nicer situation for my head as well. I know this isn't the perfect analogy, but the HANS reminded me of having my head attached to a rope. Not so nice when you get to the end of the slack.)

But the major point is the ability of me, a 6'3", 200 pound guy, crawling through the window of an RX-7 upside down and on fire. I didn't like the look of the HANS. I imagined it would be too easy to get caught on something. (the same scenario caused me to put my net in with seatbelt buckles top AND bottom so that the net will always have a way to be released so that it falls DOWN, whether the car is right side up or not).

I'm pretty good at not panicing when the s&!t hits the fan, and this summer I had a mild test, where I felt that there was a fire starting under the car and I wanted out, WITH the extinguisher, fast. I was on videotape, and was completely out in seconds, which included all the normal steps, plus switching the ignition off, popping the wheel, grabbing the fire bottle AND popping the pins on the helmet mounts.

Finally, Comfort. I wish I could give back to back results here, but they are available to you from Isaac. They will provide both setups, I think, for you to decide. They have a rental program and they credit you the cost towards their system purchase. I will say that the Isaac is one of theose things that disappears in the heat of battle. It does make some racket in the pits, and if your car is quiet, it will be noticable. Also, backing up is now a mirrors only proposition. Which it has been for me anyway with the seat and the harness.

So, the bottom line is that I like a number of items about the Isaac better. I feel that for a Formula car, the HANS is more the equal, but in a closed roof car, I wouldn't touch it.

HANS haas been around longer, practically invented the category, but I haven't heard a rational arguement that has convinced me that they were, pardon the pun, head and shoulders above the rest. For me, the Isaac was a clear winner, and the company has performed as well as the item.

Crash testing has been light, no aches to complain about.

[logician]

I dug up the article in Sports Car Magazine on Head and Neck Restraint systems. Look for it here:

http://www.logician.com/stuff/Headsup.pdf

Sorry for the large 6MB size, but I scanned it in grey scale so that you could see the pictures of the various devices. You will probably need to download it to your hard drive first, as I've had very little luck opening large pdf files over the internet directly with Acrobat.

While the article does not evaluate the various devices, it offers some comments strongly in favor of one device from Dr. John Melvin who has been involved in testing at Wayne State. Melvin says: "The only device we know of proven to protect at the highest crash levels we've been able to simulate is XXX. YYY came close, but..." I'll leave it to you to read the article for details.

Another interesting point is some coments from Trevor Ashline, inventor of the Hutchens Device, that talks about the importance of tuning the whole system to work together. Unfortunately, it doesn't say how that might be done.

I'm trying to get someone from HANS to respond to the issues raised about extrication procedures with HANS. I'm interested to hear what their response will be to some very good points raised here.

-Juan

[ErVikingo]

Hey Juan,

Thanks much, I was looking for this article!!!!

Later, Juan (also!)

[Jack Olsen]

It's nice to see the article being written, but it underscores the need for the kind of third-party testing you talk about, Juan. I wish they had included more on what Melvin is basing his opinons on.

[gbaker]

Originally posted by JackOlsen
It's nice to see the article being written, but it underscores the need for the kind of third-party testing you talk about, Juan. I wish they had included more on what Melvin is basing his opinons on.

I agree, Jack.

A lot of people have complained to the SCCA about that article. All we have is one person's opinion and no comparative data.

[logician]

I got a reply from Ken Adams of HANS to some questions that I culled from this thread. Here is my Email to Ken:

> Hi Ken,
>
> Thanks for your reply about answering some questions raised in an online
> racing community. As you suggested, I will ask you a few questions
> through Email and will post your reply to the group.
>
> 0) H&N systems should be certified in the same way that our other safety
> gear, helmets, belts, seats, suits are certified by Snell, FIA, SFI,
> etc. The sooner that happens the better. What is the H&N device
> industry doing to develop objective standards and obtain
> certifications? Is there a time frame when this might happen? I
> understand that HANS has FIA certification. However, I am uneasy with
> this situation because HANS is the only device that is certified. It
> would seem to me that different designs probably work better in
> different applications, so other devices should be certified as well.
> In particular open vs. closed cockpit applications.
>
> 1) Some drivers have expressed a concern about the use of HANS in closed
> cockpit cars. The HANS yoke makes it difficult to get out of a car if
> still attached. Some of has saw Jeff Altenberg's HANS get caught as he
> made an emergency exit last year out of a Speedvision prepped sedan.
> Practically speaking in many emergency situations, the driver would have
> to take off the HANS yoke, presumably disconnecting it with the quick
> release straps. That is what I found when practicing climbing out of
> the window in my Miata while wearing HANS. While Isaac has been
> criticized because of the need to release the device to free the driver,
> this is essentially the same as is required for HANS in emergency
> situations. HANS also has the disadvantage of needing to remove the
> yoke in addition to disconnect the helmet. Does HANS recognize these
> issues with their device in closed cockpit applications, and what might
> it be doing to address them?
>
> 2) Some drivers have expressed concern about extrication of a driver by
> EMS crews: the extrication debate is a tough thing to test since every
> crew/ situation will be different. I tried on each H&N restraint(Isaac
> and HANS) and came to the same conclusions that the test did. The HANS
> makes it rather difficult to get out of a 911 in the best circumstances.
> Having had the experience of removing folks from cars I believe it's
> imperative to give the EMS community a thorough demonstration of how
> each system works. Something that I can see coming out of this are new
> protocols for EMS crews regarding neck braces and backboard
> modifications. IMO, the HANS presents a lot of logistical and procedural
> issues regarding spinal immobilization that the Isaac does not.
>
> 3) There is some talk about the relative benefit of Isaac over HANS for
> side impact collisions because the shock absorbers in Isaac might
> provide more support than webbing based systems. Do you have any
> comment on this comparison?
>
> 4) Do you have any comment on the relative benefits of webbing vs. shock
> absorber used in Isaac? Are there disadvantages to the rigid shock
> absorber design used by Isaac?
>
> Many of the racers have been very frustrated with the lack of
> independent evaluation of the various systems. Some raw data from crash
> testing measurements is available, and the manufacturers promote their
> particular numbers. But without standards in place, I don't really know
> how to interpret these raw figures, or compare the various figures
> quoted, not all of which are under the same conditions or take the same
> measurement. What should I be concerned about, 30 degree impact, HLR,
> HIC, maximum G, etc.? Further, the issues extend beyond simple
> quantitative measurement, as the questions above about egress and
> extrication show. So at this time, we have little choice but to try to
> gather the best information possible from different sources, including
> directly from the manufacturers. Thank you for your help! I appreciate
> your efforts to increase the safety in our sport.
>
> Juan Pineda
> SFR SCCA
> 1600cc SM

Here is Ken's reply:

Juan,
I will try to answer your questions as completely as possible...

0) The HANSŪ device is currently FIA Certified for all FIA sanctioned events
(F1, FIA GT, FIA ProRally). This certification is for all models of our
device from our 30 and 40 Series (F1, CART, Etc.) all the way to our Series
20 Economy (Club racing, Etc.). The HANSŪ reduces head and neck loads
effectively in both upright and reclined seating positions. It is the FIA's
position to include which devices they choose to certify. The have examined
several others, but I have not heard of any further results.

1) We encourage drivers to practice getting in and out of the car with the
HANSŪ device on. Nobody, and I mean nobody disconnects the device from the
helmet in an emergency situation. They all simply release their belts and
get out with the device on. There have been countless situations in NASCAR
when an oil fire/impact has caught the car on fire and the driver simply
gets out with the device on his shoulders. The device is small enough now
to where it really does not impede as much as most people think..We do offer
the option of quick disconnect tethers. We have also been working closely
with chassis manufacturers with regard to window openings and harness
mounting to make cars more compatible with HANSŪ.

2) We have worked closely with several safety crews when it comes to driver
extrication. This is really a non issue, as the safety crews usually just
cut the tethers and remove the device. In cases where the drivers head and
neck has to be immobilized, the HANSŪ itself has been used as the rear half
of a Philadelphia Collar. All of these issues were addressed by FIA,
NASCAR, and CART when it came to their implementations of the device.

3,4) The simplicity and consistency of webbing makes it far superior to
dashpots/metal rods. That is one of the reason the HANSŪ is such a robust
system, it's simplicity. There is enough compliance in the human body, as
well as the shoulder harness to bring the head to stop gradually, every
time. The tethers functioned well even in the 100G sled test (the most
severe sled test ever performed with regard to Head and Neck Supports) We
are always looking into innovations and ways to improve, but we haven't
found a substitute for the tethers that offers a performance/user-friendly
advantage. The thought of metal rods anywhere near your head or neck scares
us, as we have seen a head and neck restraint with such a piece spear the
helmet off of the crash test dummy on an impact rebound.
In side impacts, no device really does an adequate job of lateral
restraint. That is what reinforced head supports and cockpit surrounds are
for. If you don't/can't have either, you can always add triangular nets
from the rollcage to the dash as the ASA series has mandated. Those nets
are standard fare in the ALMS Corvette program as well as the new Cadillac
CTS-V GT car. A head and neck restraint is only part of the complete safety
package. A good seat, harness, and side head supports/nets are vital to
keep you safe out on the track.

When it comes to test reports,(HIC, G's, Impact Angles, Delta V, etc)
we know it can be a bit overwhelming. The main thing is to have test data
done by independent sources. There are several companies that are putting
out test data that is intentionally misleading. This is simply a marketing
ploy. There are several accurate tests that have been conducted by SAE,
GM/Delphi, and FIA that are third party and in the interest of their
respective drivers/series. I will attach a summary of such a paper to this
email. Do not trust bar graphs without numbers, or tests conducted by
someone with a vested interest in the product. Tests that show direct
comparison with the same lab conditions, impact angle, and mph/G's are best.
I would also like to see some industry standard set to evaluate head and
neck supports. It is in the works. I just would like to see it happen a
bit more quickly.

Finally, look at the professional drivers. What are they wearing?
There is a reason for that. It isn't a matter of money or sponsorship for
them. They just want to be as safe as they can be. There are experts
analyzing every new device on the market to see if it is better than the one
currently in use. If someone builds a better mousetrap that protects the
driver even better, more power to them.

Thank you for your interest. Please let me know if I can be of any further
assistance.

Ken Adams
Customer Service Director
Hubbard/Downing, Inc.
"Put your safety in our HANSŪ"

HANSŪ is a registered trademark of Hubbard/Downing, Inc

The attached document that he sent me is here:

http://www.logician.com/Stuff/ComparisonSheet06.doc

And here is a PDF version:

http://www.logician.com/Stuff/ComparisonSheet06.pdf

If you have followup questions, I'll collect them and send them in a second Email.

-Juan

[gbaker]

Originally posted by logician
Here is Ken's reply:

"There are several companies that are putting out test data that is intentionally misleading."

Yeah, and one of them is Hubbard/Downing, Inc.

The documentation Ken Adams supplied draws on data from SAE paper #2002-01-3304, which is flawed--and Ken Adams knows it. So do Bob Hubbard and Jim Downing, who were sitting in the front row of the audience at the SAE conference when the paper's lead author, Dr. John W. Melvin, announced the errata.

[logician]

Gregg,

A few followup questions for you.

1) Can you tell us what was the verbal erratum that Dr. Melvin gave with the presentation of his paper. I would like to understand that fully when I look at the papers.

2) Adams writes about Isaac: "The thought of metal rods anywhere near your head or neck scares us, as we have seen a head and neck restraint with such a piece spear the helmet off of the crash test dummy on an impact rebound."

I too had been concerned about the proximity of the Isaac rigid shock absorbers to the driver's head and neck. But I didn't know what to make of it. Can you tell us about the tradeoffs here?

3) When asked about the benefits of the Isaac shock absorbers compared to the HANS, Adams states: "There is enough compliance in the human body, as well as the shoulder harness to bring the head to stop gradually, every time. The tethers functioned well even in the 100G sled test (the most severe sled test ever performed with regard to Head and Neck Supports)"

Do you agree? In what cases would the shock absorbers be required compared to the webbing? Also, at what G's will the shock absorbers begin to fail?

Any other input with respect to HANS' Email would be useful too. I hope to send HANS a followup next week.

Thanks!
-Juan

[jpachard]

Juan, As I understand it, webbing is a static material, at least in the context of the Search and Rescue and climbing fields. I have wondered too how HANS is spec'ing this material and if indeed they are using a dynamic webbing to attach the helmet to the collar.

Cheers, James

[logician]

Juan, As I understand it, webbing is a static material, at least in the context of the Search and Rescue and climbing fields. I have wondered too how HANS is spec'ing this material and if indeed they are using a dynamic webbing to attach the helmet to the collar.

James, I'd be happy to add that question to the ones that I have for HANS. Can you explaine about what you mean by "static" vs. "dynamic" webbing? I am not familiar with the terms. Does this have something to do with the material's elasticity or plasticity?

-Juan

[jpachard]

Juan, you are correct. In the context of webbing and rope, static means that the material is designed not to stretch( very bad for climbing ropes since the rope stops you suddenly). Dynamic means the material will stretch a given % over a specified distance.

Cheers, James

[jluetjen]

James and Juan;
The webbing used in seatbelts is designed to stretch in an accident. This is why it is important to discard your seatbelts after an accident and get new ones. So I don't see anything unusual about the straps used in the HANS devices doing the same thing.

[lateapex911]

What do the HANS folk think about the webbing degradation over time that has become a big concern for all the sanctioning bodies? (regarding harnesses)

Currently the SCCA, and others are on a two (three if purchased on the right date) year replacement plan.

Also, what are their thoughts regarding the relatively poor performance in lateral situations, and the percentage of lateral incidents versus straight on?

[logician]

What do the HANS folk think about the webbing degradation over time that has become a big concern for all the sanctioning bodies? (regarding harnesses)

Currently the SCCA, and others are on a two (three if purchased on the right date) year replacement plan.

Also, what are their thoughts regarding the relatively poor performance in lateral situations, and the percentage of lateral incidents versus straight on?

Actually the SCCA article talks about both those points. Melvin recommends that you replace the straps in HANS, Hutchins, and all the devices that use webbing, same as you replace belts. Trevor Ashline says that all H&N restraints work only in frontal impacts, and cites the importance of nets and the whole system.

Actually, there is a very good thread by Vaughn Scott on Renlist that gives some really good info H&N restraint systems:

http://forums.rennlist.com/rennforums/showthread.php?threadid=126126

Here is the text from the post (sorry for cross posting, but it seemed like the right thing to do in this case).

Notes from presentation by Tom Gideon, GM Race Safety Eng.

Here's my recap from the presentation I attended last night.

I just attended, last night, a presentation by Tom Gideon, a GM Race Safety Engineer, to our local road racing group, Waterford Hills Road Racing. Tom is one of those guys who is working regularly with crash-testing the latest gear at Delphi and Wayne State. He has worked on crash safety for all the GM race projects, notably (for us) the C5R, CTS-V, and Cavalier Drag car, as well as of course NASCAR and IRL. The presentation he gave was a version of what he presents to the pro drivers, and was, for me, essentially a recap of safety info presented by Dr. John Melvin in 2000 to the Detrot SCCA Region, with the latest updates in crash safety.

It was extremely timely, given all the discussions going on here and elsewhere online about H+N devices, side impact protection, and the like. He actually focused more on lateral and oblique impact protection, as I was hoping; the head-on impact is fairly well understood now and protected against, not to mention the least likely kind of impact to be experienced in our type of racing (IMO).

To recap on the straight-line stuff, you need (for best protection) a 6- or 7-point harness (properly secured, of course), H+N restraint (of which the HANS is the best for this impact, according to their data and tests - note at this point that I have an ISAAC, not a HANS), and the proper SFI padding on cage bars (though this comes into play more on lateral hits). The 5-pt harness is NFG - no good - compared to the 6- and 7-point; the added movement allowed more than doubles chest compression, from an average of 20mm (with a 6-pt) to about 50mm avg with a 5-point. This is about 2 inches. This also happens to be where the sternum will break. The solution to preventing the sternum breaking is the 6-point harness, not the sternum strap. Actually, in their tests, the sternum strap shows potential to injure the neck. Don't go there, kids!

The ISAAC apparently suffers from the same limitations as the Hutchens, D-Cel, et al in the full frontal impact; where the force is applied from is less-than-optimal, reducing the effectiveness of the device. The HANS, because of the collar, is applying force from a much better direction, and this is why it is more effective. To put numbers to it, the threshold for basal skull fracture or other injury is 4000N (tensile force on the neck). The HANS reduces this to 2000N in their benchmark frontal impact test (sorry, don't remember for sure the numbers, but I think that was 40G, 35mph). By contrast, the ISAAC, Hutchens, etc all apparently end up at around 3000N - enough to save you, but less effective. But the HANS does have its limitations - in lateral. It only contributes in a 45 degree angle; beyond this angle of impact, it will not help control head motion. This was why I selected to go with the ISAAC; again, while not as effective in straight-line, it appears to (based on analysis of design and my personal experiences) provide support and motion control in all up to 90 degree impacts. More on my personal testing of the ISAAC later.

For lateral impact, it was VERY clear that the BEST thing you can do, the most important step - was not to buy the $2000 seat! It was to buy the $75 NASCAR interior side impact net and mount it properly! It catches the shoulders and head and controls motion to the other side of the car (to make it PC for anyone driving a RHD car . The window net and cage provide the same protection on the outer side (LHS) of the driver. Even in the case of a very fancy seat, the net is necessary to back up the support of the seat. The net he had there, to show, happens to be the same one I just bought, from BSR Racing ($75 as mentioned), and that is what they test with. He had numerous test videos shown (from the sled, along with one actual in-car from a hit by Johnny Benstead) showing performance with and without the net. Even with a HANS, as mentioned, in a lateral or 45deg hit, the test dummy is bouncing or coming close to bouncing off the cage bars, and the motion of the dummy is very poorly controlled (really, not at all). Even the fanciest aluminum seats are less than 100% effective without the net. Here's the BSR webpage:
http://www.bsrproducts.com/homepage.cfm

The net, to speak of its installation, straps to the members of the main hoop of the cage to position it vertically to catch the shoulder and helmet. It should be positioned next to the shoulder, and continue straight forward to the dash bar. There is a quick release up by the dash bar, and a ratchet will tension it as required. Since my cage is a little less complete than a NASCAR car, I will need to call BSR back and clarify some fine points on installation. However, their tests have shown that even without a perfect installation, it's better than nothing. Just like a H+N device - something's better than nothing, even if it's not the very best.

But it was clear that the 100% solution was to also have a seat that will provide some degree of shoulder support, to help, in combination with the net, to support and control the driver laterally. I did ask him, specifically, if these big bad aluminum stock car seats were necessary to get all the lateral protection, and much to my surprise he did say NO. Basically any decent sort of seat with some form of support in the shoulders, when backed up with a right-hand-side net, was OK, though I still get the impression that the more stout construction and design of these aluminum seats with shoulder and head supports are still just a bit better than some of the really light-duty composite seats with very minimal shoulder support. However, if choosing between shoulder and head support, clearly the shoulder must be stopped before the head - or you get compression loading of the neck, instead of tension loads! Restraining the shoulders is the key.

Back to the padding - it's been expressed well before, but again, anywhere your helmet can hit MUST have the SFI-approved padding - the stuff that's hard. The pipe insulation stuff doesn't cut it, and can split or send you rebounding. Neither is a desireable result. This tends to be an issue more in lateral than longitudinal hits.

As to my personal experiences; as mentioned, I have an ISAAC device, which I started wearing last year. No issues with head movement, time to connect/disconnect, etc. I also crash-tested it in a lateral impact last year. I went sideways into the armco at maybe 60mph (in my 924). The back hatch was blown out, the right rear fender caved in, and the rim and right rear trailing arm bent - the hit was also slightly rearward, as I was going backwards and hit the wall that was driver's side left when normally driving on the track with the right side of the car. For my protection, I had only 6-point belts, a bottom of the line Kirkey Economy seat, and my ISAAC. My head bounced off the petty bar (unpadded) and cracked the helmet (Bell M3). I felt a little woozy, had a little tunnel vision shortly after, but oxygen cleared that out. I had mild headaches for the week following, and that was it. No other injuries. I'm glad I had the ISAAC, for the lateral support it gave (verified later by ISAAC LLC as I sent it in to them for evaluation). I also did a lot of stupid things, and got really lucky and got away with all of them! Cheap seat, unpadded bars on the cage, no interior lateral support, and driving hard on an untested chassis going for a last-lap pass. The seat will be upgraded or replaced, the petty bar is coming out (not worth the hazard), the interior net goes in, SFI padding for everything else, and I will never tell myself (while on track) - the motor's blown, you're not racing this car again this weekend, you've got nothing to lose by trying for the pass! Boy was I wrong - you can always demolish your car and put yourself in the hospital!

__________________
Vaughan Scott
'79 924 ITA/GTS1 #77 Blue/White
'81 931, '82 931
http://www.924.org
http://www.gtschallenge.com

I noticed on TV that some of the Speedvision Challenge cars have interior nets. I think that's the way I will go for lateral restraint.

-Juan

[lateapex911]

I agree Juan...and the interior nets have the added benefit of easy removal, and to sme degree, visual transparency.

I like the cool seats (Momo, etc) with the extra section for head and shoulders lateral restraint, but from an ingress/egress point of view, I have worries that they would make a potentially small opening even smaller.

On the downside, if the car is against a barrier or on its (left) side, the right side might be the only way out, and if the car is filled or filling with smoke/flames, an additional item to figure how to disconnect is an issue as well.

But, we have to do a little "potential" analysis, and it's clear that its I would rather be conscious and at least able to attempt getting out after an incident, rather than injured and unable to fend for myself.

[lateapex911]

Regarding the comments by Vaughn relative to the force reductions at different offsets, here is a chart showing the major players at a 30 degree offset. It would appear that right around here the Isaac and the HANS are roughly equal, with a slight edge going to Isaac.



I will point Vaughn to this thread. It would be nice to be able to plot all the devices on a matrix , and see which are better at what, but this is the closest I have found.

I agree with Vaughn that a straight on impact just isn't that likely. In my crashing experiences, it has never happened. Even the one that LOOKED like it was going to be straight in was an offset when I finally hit.

[lateapex911]

Here are Vaughns thoughts on the HANS response. He requested I repost for him from his posing at: www.Improvedtouring.com in the general discussion area. To see the entire thread in it's context, go here: http://forum.improvedtouring.com/it/Forum10/HTML/001281.html

Arrgh... it starts to get annoying... Plenty of wiggle room in these discussions now, which starts to pi$$ me off. First of all, the response from HANS/Hubbard-Downing is not from Hubbard or Downing, but a sales guy. Screw that, lemme talk to the engineer! Plenty here are engineers, and I happen to believe (based on previous discussions) that those who are not are perfectly capable of reviewing numbers and summary data to verify conclusions. Don't try to simplify things for me - you're insulting my intelligence!
Amusing to note that Gregg's response to my request for video was the observation at how meaningless position is vs. force data (true) - in contrast, the pretty little sheet from Hubbard-Downing (linked in the other thread, here it is:
http://www.logician.com/Stuff/ComparisonSheet06.pdf) is pictures from the crash tests, not even video, with some numbers to the side.

Hell, let's tear the HANS sales rep's response apart point by point, for consistency.

0) The HANS is currently FIA certified. I should damn well hope so, given that it's being used in F1! Of course, as I think we all well know, impact considerations in a single-seat formula car are a little different than a sedan. But that's besides the point. Is the HANS the _only_ FIA certified device? He claims ignorance here, which is correct and valid depending on when he makes this statement. But we must also examine exactly what the FIA is certifying here - as examined on rennlist, their seat certification is less than impressive (though better than nothing) and sometimes "FIA-certified" is taken (in discussion as a blessing from the hand of God, far more than I think even the FIA consciously wishes it to be. BTW, anyone else note that the FIA H+N testing procedure seems to be nothing more than a quality test for the HANS device? I don't even know how you could test and ISAAC, Hutchens, et al on that rig. Read the test procedure. We LOVE the FIA!

2) Sounds like behavioural modification to get over limitations of the system. I regret that I am unable to work with Porsche to have them redesign the window opening of my '79 924 to ease my egress with a HANS device. I don't think it'd be IT-legal. Of course, I've chosen a device which requires that I release it myself when I exit. It was the first thing I popped, reflexively, after the last time I crashed; then I thought to myself and made a conscious decision to NOT unbuckle, since I was still in an impact zone. Only the Hutchens and D-Cel may have an advantage in this area, but I'm willing to make a tradeoff on ease of egress before I compromise on performance. No big deal here, IMO.

2) The link earlier in the thread to RSI Safety would seem to contrast sharply with this statement: http://www.rsisafety.com/ Perhaps, while the Philly collar works well with the HANS, it's not so readily available at the lower levels? I know Hubbard-Downing has not come out to Waterford, or to meet with our local F+C and safety crews, to address this. Heck, we rent our ambulance! Again, a HANS-specific issue here, and not well addressed for the everyday club racer, IMO.

3, 4) This sounds more like an appeal to "common-sense" rather than test results. As an engineer, I can appreciate how sometimes common-sense is wrong. They're appealing to the emotions of simplicity and fear. They make a vague statement which appears to implicate the ISAAC, but during a mode which sounds like complete failure, and without a direct statement of which device speared the dummy's helmet. I've always wondered why it seems like the helmets nearly come off the dummy anyway, in these impacts - as an issue separate of H+N restraint. I do agree with his statement that an internal net is even more critical, in a lateral impact, than a H+N restraint, having seen the video Mr. Gideon presented.

He further disparages the ISAAC bar graph comparison, while providing even LESS data, but more pretty pictures, to sell ihs product (noting no comparison data shown by him for the ISAAC).

And one last appeal to the emotions - hey, all the big boys are wearing the HANS - don't you want one? Yeah, well, except that a whole helluva lot of NASCAR guys are wearing Hutchens, and frankly, I REALLY don't think that's better than a HANS! I doubt Gregg would disagree with me on that one! When there's SO much data out there showing that the HANS is better than the Hutchens and D-Cel, why does anybody wear the latter?

I'm still not satisfied with the limited amount of data out there, even if I have put my money where my mouth is.

I hate salesmen, but I guess that's just the engineer in me.

------------------
Vaughan Scott
Detroit Region #280052
'79 924 #77 ITA/GTS1
www.vaughanscott.com

[logician]

Jake, Thanks for posting that chart. I believe came from the Isaac site, yes? Here is the additional info given about the chart that really should be included with it:

(Note: The IsaacŪ data is direct from testing conducted at Wayne State University Bioengineering Center. The G-Force data is from company advertising. The other data have been garnered from SAE publications and other sources believed to be reliable. All trademarks are the property of the respective rights holders.)

As Gregg stated earlier, the test data for Isaac came from the SAE paper 2002-01-3306, presumably testing done at the Wayne State test fascility. The author listed for that paper was Gregg Baker (of GTP). The Authors listed for 2002-01-3304, the source of data about HANS and other devices, was John Melvin (of Tandelta) and Paul Begeman (of Wayne State).

One thing I don't like about the Isaac chart, and all the glossy charts from other manufacturers, is that they invariably portray their product as the best of all the alternatives. It is difficult to see through all the marketing spin what is really going on, and I'm always left to wonder why they didn't compare against products that I suspect might have performed better.

I will note that the HANS data from SAE 2002-01-3304 quotes a figure of 195lbs in a 50G test. Presumably this is the data Isaac used to make its chart. So it doesn't make sense why the Isaac chart quotes a greater than 200lb figure with a lesser 45G load for HANS. Also the Isaac chart does not explain what the white areas in the bars mean.

Probably there are variations in the tests that are not explained. For example, different seating positions surely affect the measurements. What are the charts comparing: F1 seating or production car seating? Or are they mixing test conditions? I am also guessing that maybe some products do better under different conditions, i.e. 45G vs 50G vs 70G. So probably the different manufacturers pick the conditions that portray their products in the best light -- you know kind of like the quotes in movie ads.

For our purposes, we really need a comparison between the alternatives in our application -- production car seating. I would rather see that done by a third party that has no affiliation with the products being tested.

-Juan