Juan,

Great post. I agree 100%

I chose the Isaac over the HANS for egress issues. I have had the joy of having my car on fire and getting out quickly is paramount. I tried on a HANS and found it to be very bulky and awkward in a touring car. I would not hesitate to use it in a open car though. The Isaac is a very nice unit and has some very compelling data to back it up.

Cheers, James

vhttp://forums.pelicanparts.com/uploa...1080653317.jpg

James,

One point I considered when I looked at the ISAAC is that unlike the other systems, the ISAAC keeps you connected to the harnesses until you explicitly release both sides of the device. With the other systems you are free of the car the moment you release your belts. This may be a problem should you need to get out of the car quickly. It may also be a problem with safety workers that might not be familiar with the operation of the ISAAC.

Another consideration for me was the complexity of the ISAAC mechanical system, and in particular possible undetected failures of the dampers.

Every safety system has failure modes, and presumably the tethered systems are prone to breakage and other failures. But webbing is a very mature technology and there is a lot of data on it, and also standards in place for their use. That is why you have to replace or reweb your belts every 2/5 (SFI/FIA) years.

Actually one thing that really frustrated me when I was researching H&N restraint systems is the lack of really authoratative evaluation of most of the devices. The state is little better than trying to decide on the best laundry detergent based on TV ads. Every manufacturer of course publishes their own data showing how they are better or par with the others. But clearly those are biased presentations.

The one system that did stand out in that respect was HANS. While the data presented on the web site and literature looks good, being the skeptic that I am, that was small part of my consideration. More important was the fact that they have FIA certification and that they are mandated by F1. In addition, I was swayed by their status as the incumbent, given the fact that they have years of data, development, and refinement on their product.

That being said, I would really like to see competition in development of safety devices, and standards in place to assure their quality. 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.

Greg, I noted that you work for ISAAC. Can you say anything about what ISAAC and the H&N device industry in general may be doing to develop objective standards and obtain certifications? Is there a time frame when this might happen? I would beg the moderators' permission to let you speak freely on this topic even if that might be interpreted as benefitting a specific product. This is an important enough issue with so little data available, that I feel it is in the forum's best interest.

-Juan

Both systems make it harder to get out quickly. As you pointed out earlier, crawling out the window with the Hans truss is just about impossible. And as I understand it, corner workers are commonly trained to cut belts rather than mess with finding and unlocking buckles (which could be located somewhere in the middle of a fire). That said, the Isaac does need to be disconnected (or your helmet needs to be taken off) before you can get out.

You also have to make sure they're adjusted correctly (which is not necessarily going to make them the most comfortable), and that the belts themselves are kept close enough together to prevent them from slipping off. (Also, relying on the user to remember to change the belts every other year can be a little like expecting me to remember to change the filter in my furnace every six months...)

Shock absorber technology has been around for a pretty long time, too.

Quote:

Greg, I noted that you work for ISAAC. Can you say anything about what ISAAC and the H&N device industry in general may be doing to develop objective standards and obtain certifications? Is there a time frame when this might happen? I would beg the moderators' permission to let you speak freely on this topic even if that might be interpreted as benefitting a specific product. This is an important enough issue with so little data available, that I feel it is in the forum's best interest.

This moderator certainly won't object. The more discussion about this issue, the better.

I think Juan makes (as always) very good points. There are benefits and drawbacks to every system currently available. I hope that head and neck devices continue to evolve and improve, incorporating side and angled impact protection, for example, and reducing the degree to which casual misuse can compromise their effectiveness.

I am glad I asked about the HANS and find everyone's input very informative. The ability to get out of the car quickly seems very important and is hindered by both systems we are discussing. I did find that the HANS has a quick disconnect feature, essentially straps that will dangle down that can be pulled by yourself or safety personnel. Here is a pic.

Bailey

http://www.hmsmotorsport.com/pimg/ha...ickrelease.jpg

Similar to the Isaac quick-release pins:

http://isaacdirect.com/images/Product/Pins/Pins.JPG

Hi Bailey,

Yes exactly -- the quick release tethers.

I found it important when buckling up to ensure that the orange pull straps don't get caught under my shoulder belts. You don't want those to get pulled inadvertently!

Also, it's not obvious, but when you connect and disconnect the tethers from your helmet, don't do that with the quick release. Use the connectors that attach to the helmet instead. I found it very difficult to reconnect the quick release with my helmet on.

Another point you should consider about HANS is what belts to use. Schroth makes a harness that is specifically designed for use with the HANS. The difference is that the shoulder belt is 2" wide instead of the usual 3", and is designed specifically to interface with the HANS yoke. The issue here is that the HANS has to slide smoothly on the shoulder belt without slipping off the side. This is also the reason that the belt holes in the seat need to be close together and that the shoulder belts be 4" (maybe 5"?) apart on the harness bar.

In my case, I opted for 3" belts because I found that my body, seat, and belt mounting position worked fine with the 3" belts.

A note about belts: I was reading that SCCA just mandated a minimum of 6 point harnesses starting in 2007. I unfortunately just purchased 5 point. :( They also mentioned 7 point harnesses -- first I've heard of that. Does anyone know anything about them?

Regarding seats, do you have a back brace, or appropriately certified FIA seat that does not require a brace? While some older seats have been recertified to the new standard, that was not the case with my old Recaro SPG, and I had to buy a new SPG that had the correct certification. Presumably something in the old design was inadaquate for use without a brace.

-Juan

Juan,

This has turned into a very good thread, with some excellent questions and points raised.

Let me finish up some end-of-day stuff and get back to you.

Juan,

Great tips on using the HANS, which is the way I'll likely go. I am building a track/street car and safety is high on the list of priorities.

I have installed Cobra Suzuka seats and have a back brace mounted on the rollbar (opted not to go for a full cage now as the car will still be street legal).

I will be using Schroth 6-pt harnesses and am aware of the 2" HANS shoulder straps and the reasoning. While I am told that a 2" lap belt rides on the hips better than a 3" and is accepted by many race bodies, I read that PCA club racing (which I would like to do in a few years) requires 3" so I will probably go that route.

There is also a decision to be made about whether to go with pull-up or pull-down lap belts. In a prior car I found little room to get leverage with the pulldown, but appear to have the space in the 930. Any thoughts Juan, or from others regarding this?

Thanks,

Bailey

Jack,


I hope that head and neck devices continue to evolve and improve, incorporating side and angled impact protection, for example, and reducing the degree to which casual misuse can compromise their effectiveness.

This is a great point. I don't actually know this, but my sense is that the H&N restraint systems have the potential to do more harm than good if not properly applied. The danger would be in cases where both sides of the helmet might not be equally constrained, either due to failure or misuse. That would have the effect of twisting the user's head, even in a low speed incident, and that sounds bad to me. Maybe it's not a problem. But I've never heard that point addressed.

The thing is that up to now the H&N systems were mostly used in professional applications where their use was probably better controlled, so misapplication was less likely. I can't think of a more anal user group than F1!

But now H&N restraint systems are being purchased by more average users like you and me, that almost certainly can't prepare their cars with the same level of expertise, let alone the same budget as pro teams. I don't know about you guys, but I don't have the pit crew strapping me in and double checking that everything is set up perfectly.

To my knowledge there are no club tech rules or guidelines yet that address the correct application of H&N restraint systems.

-Juan

Hi Bailey,

There is also a decision to be made about whether to go with pull-up or pull-down lap belts. In a prior car I found little room to get leverage with the pulldown, but appear to have the space in the 930. Any thoughts Juan, or from others regarding this?

I like the pull up belts. The reason is that there is very little room on your lap in a race seat for any adjusters, let alone room for your arms to get leverage to adjust them. So I get the adjusters out of the way on the side of the seat.

I basically preset the lap belt lengths so that the two ends won't quite reach, and then push myself against the seat, take a deep breath, and buckle up! After a while you get to know the right pre-buckle lengths. I do find I like to tighten up the shoulder straps while I'm sitting on grid waiting to get on track.

-Juan

Hans quick release works good, and 3" belts fit very good. Find someone that has one and try it on in your car.

I the most recent issue of the PCA Club Racing news letter, SCCA's Sports Car magazine's March issue is referenced and apparently has their annual review of safety apparel, which includes a comparison of various h&n restraints. Has anyone seen this and care to share the article's findings?

Bailey

Juan,

I always hesitate to comment in any thread of this nature due to the risk of being taken as a salesman, so first let me offer up some perspective:

1) No one is going to get rich selling head and neck restraints. The R&D costs are high and the market is small. To date, less than 10,000 H&N restraints are in use--that's less than 2% of all racers. Compare that to about 500,000 artificial hips implanted annually in the U.S. alone.

We set up Isaac as a spinoff of an R&D effort that deals with biomechanical implants, hoping to save some lives, get our R&D $s back and maybe make a few bucks.

2) There is no such thing as a bad H&N restraint. Even the worse products out there will still reduce head loads by 45+%.

See jpackards post above. Getting out of the seat is one thing, getting out of the car is another. It takes a driver longer to get out of a car with a HANS device than with an Isaac system, and it takes much longer for an EMT crew to extricate a HANS user than an Isaac user.

http://www.isaacdirect.com/html/chart.html

All of this data is from the same test lab, the Wayne State University Bioengineering Center in Detroit, using the same crash dummy, crash sled, crash pulse, etc. and, except for the G-Force data, has been reported in peer-reviewed SAE publications. It's not "our" data, it's the lab's data.

Load data for the unprotected dummy was published by the SAE years ago. What we have listed as "Webbing" covers the Hutchens, D-Cel and Wright devices, all of which perform in the same range depending on how tightly they are worn. We helped fund the Wright device testing and Jay Wright has the data available at www.over40racing.com.

The G-Force data is taken from company publications.

Data for the Hutchens, D-Cel and HANS device are published in SAE paper #2202-01-3304.

Data for the Isaac system are published in SAE paper #2002-01-3306.

Don't be so cynical. The vast majority of companies have spent a great deal of resources to help eliminate the #1 cause of racing fatalities. Why would they lie about their product's performance when it would be so easy to prove them wrong? There is only one company that knowingly uses incorrect data in promoting it's own product.

FIA refuses to test an Isaac device. Why? Because it has a distribution arrangement with Hubbard/Downing, Inc. for the HANS device. If you invented the perfect H&N restraint tomorrow, FIA would not test it. Didn't know that, did you?

Look for "Percentage Head Load Reduction" (HLR) to appear as an accepted measure of performance. We initially used this on our Web site but people were not up to speed on the concept, so we switched to absolute load levels. After chatting with Art Kuhn at SFI and some of the sanctioning bodies, it looks like the idea is catching on. Simpson and HANS have been using this measure in their ads.

It's a simple idea and eliminates issues like absolute Gs, but only works for a particular type of impact, e.g. frontal, offset frontal, lateral, etc.

Bailey,

It had photos and a little writeup about each product, but there was no info regarding relative performance.

There was a recent study done too on extrication with various head and neck restraints. The Issac took the Paramedics an average of 60 sec to remove the driver from a sedan and the HANS too an average of 90 sec. Being a paramedic in a past career I have a healthy respect for what these folks have to do. In our local region we will also be showing the flaggers and medical staff at the track the various devices and give them an opportunity to get some hands on experience with the drivers hooked into the car.

Cheers, James

I use the D-Cell system. I love. It also has 2 straps that hang in front that are pulled to release the helmet for quick excape from car.

Very easy to climb out of window with this system.

H&N system certification
 

Hi Greg,

Thanks for yourreply. Actually, I looked into a few other threads that you had posted to also and found some good discussion there. First, I'd like to say that I really appreciate your efforts and that of others that are working on H&N restraint systems to improve our safety! A few followups:


Actually, what you say only reinforces by cynicism. How do Iknow which manufacturers' claims are (knowingly or unknowingly) inaccurate? Even if only one is inaccurate, which one is it? Am I playing Russian Roulette? The user has no choice but to be cynical with the current situation where only the HANS carries any kind of certification.

What about SFI, or maybe Snell? FIA is not the only certification body. Why not pursue certification through these or other organizations? I think most of us use some SFI and Snell certified equipment that does not also have FIA certification.

Can we expect to see some certification through these or other bodies in the near future?

There are other topics in this thread that I would like to discuss, but I will post those separately.

-Juan

interested in this statment about the HANS, I use the quick dosconnects all the time, I find them easier, is there a technical reason behind this or is it just a preference?

Jim