Tuesday, June 18, 2013

Helmet Safety

Let's talk about what makes a good helmet. This is something that I've discussed elsewhere but never in detail here on my blog. The topic comes up time and time again and it always surprises me how little people seem to know (or care) about what they use to protect their head. When I started paddling I did a fair amount of research to educate myself. I'll share my findings and developed beliefs to try to make things easy for folks.

A quick note about design: if you're more worried about how it looks, then maybe you should find another sport. Yes, there's fashion in kayaking. But it should always come after function, especially when the function is safety.

To a certain extent, the most important thing is that the helmet fits. If it doesn't, it won't stay on when it's needed or the owner won't want to wear it in the first place. Make sure it's comfortable. Take your time to outfit it well. Add some fit pads so it comfortably touches in many spots Adjust the chin strap so it's tight - it should make chewing a challenge. When you shake your head no the helmet should move with your head, when you push on the brim it shouldn't lift off your forehead. It should come down low enough to cover your temples and your occipital lobe (lower back of skull).

You can't tell how a helmet will fit and what it will cover without trying it on. Some small looking helmets actually cover the important areas. Some large helmets might still sit too high on the head and leave your forehead exposed. Try it on, look in the mirror, get a friend to tell you how it sits in the back. There's no other way than trying and I often take up to an hour to adjust and pad out a new helmet.

After the fit, the most important thing is the foam. Lots of people want to know what the shell is made out of, but it's not nearly as important as what foam is inside. And most people don't even ask what it is.  It's the foam that absorbs the energy of an impact - especially the big ones. There are different types of foam but all kayak helmets are made to absorb multiple impacts. That means the foam takes a hit and absorbs the energy without permanent deformation. (bike helmets, on the other hand, are designed to take a single impact after which they have lost their ability to absorb energy).

Some foams are better than others. The best is EPP (expanded polypropylene). It's got better energy absorption properties than standard minicell (often EPE - Expanded Polyethylene or EVA - Ethylene Vinyl Acetate). And all foams come in different thicknesses and densities. The dense stuff isn't as comfy but it absorbs more energy. Lots of companies either have two layers (a dense outside layer with a thinner, comfier liner) or they have fit pads that are softer to make the fit more comfortable. If you can compress the foam with your hands to touch the shell it is too soft or too thin.

And important thing to note is that even though helmets are designed to handle repeated blows, if the impact is large enough it will deform the foam and limit it's ability to handle more blows in the future. BUT YOU CAN'T SEE IT. You may not notice any difference in the foam but if you take a large hit you should think about retiring your helmet even if it looks fine. Some people talk about 'repairing' their cracked helmet - even if you do repair the glass shell you can't repair foam. It would need to be replaced.

The shell is the least important but the most noticeable thing about a helmet. Carbon fiber is light, stiff and expensive. Does it protect you better than plastic? Maybe. A stiff shell can spread the force of a point impact across more of the foam. That's good if you hit a sharp object. But fiberglass or a stiff plastic will do almost as well as carbon. A soft plastic won't do well at all - you want a helmet, not a piece of tupperware.

Another thing of note is shape. Helmets with a large brim (like the Sweet Strutter) can catch current and exert a tremendous force on your neck pushing the helmet back. Not good for surfing - river or ocean. Full face helmets can protect your teeth (and good looks) but can limit your communication. Some people talk about the danger of snagging the front bar of a full face, but I've never heard of it happening. On the other hand, I personally know several paddlers who have lost teeth and so does everyone else.

So take your time and put some thought into your helmet. You don't need to spend a ton of money - the most expensive is not always the best or necessary. But start with what fits. Pay attention to what it's made of. And keep in mind what you are going to be using it for.

For the record, I use a Shred Ready Shaggy fiberglass helmet for most paddling - teaching, easy whitewater, ocean playing. Good stiff shell, EPP foam, small brim. For class IV/V whitewater I use a Sweet Rocker Full Face - carbon shell, full coverage, lots of EPP foam.

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