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 Post subject: Helmet Design Considerations
PostPosted: Wed Mar 17, 2004 3:56 pm 
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culliford wrote:
Research on bicycle helmets indicates that those with hard foam cell material were effective in reducing the energy from a blow experienced by the brain. Helmets with soft foam padding were not helpful in reducing brain injuries, only reducing abraisions.

All of the kiteboarding helmets I see use the soft foam material. Are not the same forces at play in kiteboarding?

Is there any reason that the hard foam padding is not used, such as exposure to salt water? Is it a reasonable trade off, safety vs durability or possibly comfort?

Is there any data on brain injuries experienced by kiteboarders vs type of helmet or lack thereof?

I know that other watersport helmets, e.g. kayak, use soft foam but there I don't think that the energy involved is comprable.

Is there any reason not to use a snowboarding helmet, some of which use the hard cell foam lining?

Dave Culliford


Hello Dave,

I have looked into available helmet research a fair amount and have read similar conclusions to those that you mention in your post. A fair body of research and accident data relates to bicycle helmets. The vast majority of bicycle helmets have expanded polystyrene (EPS or styrofoam), liners. Apparently, this non-reuseable lining material has superior impact protection qualities. Of course once you use it to protect against an impact you need to replace the helmet. If it saves you from serious injury, so what and buy another helmet.

Image
Graph from:
http://www.grantadesign.com/resources/m ... helmet.htm

Most of the polystyrene helmets don't appear to be particularly suitable for kiteboarding because of weight, bulk, projected area/drag characteristics and water retention traits (i.e. "bucketing potential"). That is virtually ALL bicycling and motorcycle helmets and many kayaking helmets don't appear to be suitable for kiteboarding as the helmet itself could do cervical or spinal injury through routine impact related whiplash or added mass effects caused by water retention and/or drag. There are few other sports in which you accelerate to high speeds routinely and then deccelerate rapidly upon impact with water such as you do in kiteboarding. This special set of conditions places serious constraints on practical head impact protection.

Many watersports helmets use crushable foams that can sustain mulitple impacts without requiring replacement. These foams also appear to have lesser impact protection qualities than the EPS foam. More about various helmet foams appears at:

http://www.bhsi.org/foam.htm

For now, there are VERY FEW purpose designed and built kiteboarding helmets. We need to select a helmet originally designed for another activity and use it for kiteboarding. There are some impact tests and certifications in existance such as those performed by the Snell Memorial Foundation (http://www.smf.org/testing.html), ASTM, ECE, CPSC, CF, CSA, etc. There are some standards being evaluated for white water rafting but none to date for kiteboarding that I am aware of.

I have a skiing helmet that does a nice job of head protection and heat management while skiing. It appears to be unsuitable for kiteboarding however based upon its weight, potential drag and poor drainage potential. I would be careful in evaluating other helmet types for kiteboarding. Cervical injuries can last for a long time.

The performance envelope within which a kiteboarding helmet must function is fairly unique. It must remain in place and not induce neck injuries despite routine impacts against water on the order of 20 mph and perhaps much higher. It remain in place without displacement through these impacts against water and potentially against lower speed impacts against hard objects. It must drain water readily and not unduly retain excessive water weight through either absorption or simple collection. It must be comfortable and lightweight. It must have an impact resilent shell that isn't readily pierced. It must have highly shock absorbant lining that doesn't unduly add weight or bulk. This liner could be either used through mutiple impacts or discarded after a single impact after the liner has been compromised. The helmet and hardware must be corrosion resistant. It must have excellent fit and positive fastening. The helmet must not unduly obstruct vision and hearing, etc. etc. etc. Kiteboarding presents a demanding design and performance environment for helmets.

The KSI presents a fair number of reported kiteboarder impacts and related head injuries and resulting symptoms. It is very difficult to accurately compare accidents and resulting injuries give all the unique details of each case. It would appear to be fair to say that a good helmet should reduce resulting injuries from an impact as opposed to having no protection whatsoever. The data for bicycle helmets supports this conclusion as well.

Look in the KSR at - http://groups.yahoo.com/group/kitesurf/ ... EFERENCES/

Some ideas on helmet comparision and selection appear in the KSR under: 1b. Safety Gear Ideas

The Protec Ace Wake helmet seems to be fairly popular with kiteboarders. Many riders were seen wearing this helmet at the recent Velocity Games competition in Texas, USA. It has stiffer crusable foam (not EPS), and in theory may have better impact absorption qualities than the Protec Water Helmet that uses softer crushable foam. There are other helmets in use out there. It would be good to hear about people's experiences with various helmets.

Originallyl posted at:
http://www.kiteforum.com/phpbb/viewtopic.php?t=12309


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