Helmet Life

[mauisher]

Hi Everyone,

How often do you replace your cycling helmet? I'm considering replacing my 2008 Giro Atmos helmet, which has seen a lot of miles. However, it still looks OK and hasn't been crashed. What do you think about the need to replace it? Thanks!

[Tri Girl]

I get a new helmet every 3 years whether it's been crashed or not. I don't know if that's the norm, but it's what I feel best about. I figure that all the time in the sun, the accidental drops of the helmet off the bars or whatever warrants replacing fairly frequently. I feel better about it anyway. Plus- at roughly $30 a year (for a $90 helmet replacing every 3 years), it's cheaper than most other bike maintenance and it's my brain- so I don't mind spending the money.

[OakLeaf]

The manufacturers now say three years from first wearing on some of the newer helmets, and that makes sense to me, with the increased surface area of lightweight helmets. The surfaces are what get exposed to body acids and oils, UV light, ozone, and all the other things that degrade EPS.

Neither Snell nor BHSI has revised the five-year rule that has been the recommendation since before they even had websites.

Do be aware that the clock starts from first wearing, not from manufacture, assuming a helmet has been kept in the box, not displayed in the sun and not tried on excessively. If you're buying a hat that's obviously been on the LBS shelves for a while, I probably would go from the manufacture date (and try to negotiate a discount accordingly).

So between those two ... I don't know that anyone here has the expertise to really say. I'm with TriGirl, it's my head, I've landed on it or near it enough times to not mess with it. I don't start panicking when three years have gone by, but somewhere between three and four years I'll replace it (assuming I haven't landed on it sooner ).

[Catrin]

I just replaced my lovely blue Bell from last year because it looked pretty beat up to me. I didn't have any falls with it, but it has fallen enough off of the car, in the apartment, etc. I figured it was best not to take chances. Hopefully I can take better care of my lovely new purple Bell


Not that my helmets have to match my bike or anything...

[PscyclePath]

The manufacturers say to replace helmets every three years, but then they're in the business of selling helmets, sort of like the car dealers who want you to trade in just about the time you get your old one paid down enough to be almost tolerable ;-)

Helmets are made from extruded polystyrene foam, pretty much the same stuff that those foam coffee cups are made from. It doesn't break down from exposure to sunlight, or oxygen, or much of anything else. You can dissolve it in an organic solvent, or melt it if you apply enough heat (~85 degrees C). The coffee cup you throw away today will likely be perfectly usable when they dig it out of a landfill 500 years from now, provided that you wash it up a bit.

So the foam in the helmets doesn't degrade. What I have found out is that some of the ancillary stuff, like the plastic coating on the foam might get scuffed up a bit, or more likely the headband/suspension system will wear out or get all ratty-looking.

Replace your helmet if you crash it, or you drop it in a situation where it might compress or crush the foam. Replace it if the parts start to get all ratty and worn out. Replace it if you get a better deal on a helmet that you like better. But there's not really a time limit on the foam degrading, other than when it gets crushed.

[OakLeaf]

The coffee cup you throw away today will likely be perfectly usable when they dig it out of a landfill 500 years from now, provided that you wash it up a bit.

You've obviously never done park or beach cleanup...

Those coffee cups do crumble. No telling how long they've been out there of course (within the past year I've found pop/beer can pull tabs, that haven't been used since the 70s), but they crumble.

And body acids and oils? Cosmetics/hair products/sun protection products based on vegetable or mineral oils? Various types of organic solvents...

[shootingstar]

I've worn helmets nearly daily during warm seasons....for 5 yrs. and over.

If I haven't crashed and the padding inside ok/replaced, that's fine for me.

Plastic, sadly does not degrade that fast. (am referring more to our non-biodegradeble garbage.)

[OakLeaf]

I assume you're referring to DesertTortoise's question and not Gypsy's.

But the CPSC standard in the USA calls for helmets to be held at a maximum of 53°C (127°F) for a maximum of 24 hours.

I don't recall that the warehouse temperatures were much above that, if at all, but items could've been stored there for much longer periods.

I don't know what temperatures have been like in your area, but the fact that you've "worn" helmets in those temperatures is no proof of anything, unless you also crashed them and they performed to specification.

Plastic DOES degrade at high temperature, or when it's exposed to organic solvents like body acids and oils and cosmetic products we put on our faces and hair. EPS is especially fragile because of the way the beads are bonded together. It's meant to be fragile. That's the point of it and how it absorbs impact. As I said to Tom way back when, all you have to do is pick up an EPS cup that's been outside for a few months and crumble it in your hands. The beads don't degrade appreciably, I don't suppose, but the bonds between them do, and those are the parts of a helmet that count.

A helmet can be had for $30 and for no more than $300. Rehabilitation after a traumatic brain injury - if you even survive it - you get the idea. I've had one concussion (with a helmet) and consider myself very lucky that I'm not aware of any lasting effects. Any time I have to guess about a helmet, I'm going to guess in favor of buying a new one. No one here has identified herself as a plastics scientist with specific experience in EPS, and given that, asking about it here is no different from guessing. New helmet. That's all.

[Dogmama]

A helmet can be had for $30 and for no more than $300. Rehabilitation after a traumatic brain injury - if you even survive it - you get the idea. I've had one concussion (with a helmet) and consider myself very lucky that I'm not aware of any lasting effects. Any time I have to guess about a helmet, I'm going to guess in favor of buying a new one. No one here has identified herself as a plastics scientist with specific experience in EPS, and given that, asking about it here is no different from guessing. New helmet. That's all.

+1. Most of us don't have long term health insurance either.

Also, consider with brain surgery they'll have to shave part of your head. So you'll look weird & probably act weird for awhile.

[Bike Chick]

A helmet can be had for $30 and for no more than $300. Rehabilitation after a traumatic brain injury - if you even survive it - you get the idea. I've had one concussion (with a helmet) and consider myself very lucky that I'm not aware of any lasting effects. Any time I have to guess about a helmet, I'm going to guess in favor of buying a new one. No one here has identified herself as a plastics scientist with specific experience in EPS, and given that, asking about it here is no different from guessing. New helmet. That's all.

Great point, Oak. My helmet is 6 years old, has been dropped several times and stays in the back seat of the hot truck when it's not being used. I've had my eye on a new Giro Atmos that matches my bike that DH wanted to get me for my birthday but I felt frivilous getting it when I already had one. Your argument justified the purchase. BTW, Giro has 15% off all their helmets through 11/29/11 with free shipping over $100. It should be here in a week

[goldfinch]

Plastic DOES degrade at high temperature, or when it's exposed to organic solvents like body acids and oils and cosmetic products we put on our faces and hair. EPS is especially fragile because of the way the beads are bonded together. It's meant to be fragile. That's the point of it and how it absorbs impact. As I said to Tom way back when, all you have to do is pick up an EPS cup that's been outside for a few months and crumble it in your hands. The beads don't degrade appreciably, I don't suppose, but the bonds between them do, and those are the parts of a helmet that count.
.

More from the bicycle safety institute folks http://www.bhsi.org/replace.htm:

Occasionally somebody spreads rumors that sweat and ultraviolet (UV) exposure will cause your helmet to degrade. Sweat will not do that. The standards do not permit manufacturers to make a helmet that degrades from sweat, and the EPS, EPP or EPU foam is remarkably unaffected by salt water. Your helmet will get a terminal case of grunge before it dies of sweat. Sunlight can affect the strength of the shell material, though. Since helmets spend a lot of time in the sun, manufacturers usually put UV inhibitors in the plastic for their shells that control UV degradation. If your helmet is fading or showing small cracks around the vents, the UV inhibitors may be failing, so you probably should replace it. Chances are it has seen an awful lot of sun to have that happen. Otherwise, try another brand next time and let us know what brand faded on you.

At least one shop told a customer that the EPS in his three year old helmet was now "dried out." Other sales people refer to "outgassing" and say that the foam loses gas and impact performance is affected. Still others claim that helmets lose a percentage of their effectiveness each year, with the percentage growing with age. All of that is nothing but marketing hype to sell a replacement helmet before you need it. There is some loss of aromatics in the first hours and days after molding, and helmet designers take account of that for standards testing. But after that the foam stabilizes and does not change for many years, unless the EPS is placed in an oven for some period of time and baked. The interior of your car, for example, will not do that, based on helmets we have seen and at least one lab crash test of a helmet always kept in a car in Virginia over many summers. Helmet shells can be affected by car heat, but not the foam. The Snell Memorial Foundation has tested motorcycle helmets held in storage for more than 20 years and found that they still meet the original standard. EPS is a long-lived material little affected by normal environmental factors. Unless you mistreat it we would not expect it to "dry out" enough to alter its performance for many years.



Of course, as we are not material scientists we have difficulty evaluating what sites like these say. However, the ANSI standards say:
ANSI: Shall not alter due to age or use, or from exposure to sun, temperature extremes or rain. Must provide warning if solvents, transfers or other additions will affect adversely. Must not cause skin disorders, nor be affected by sweat or toiletries.


I thought this report interesting, about the bike helmet maker MET:

The Italian company MET says in their 2010 catalog:
"We are often asked 'For how long is a helmet safe?', or 'how often should I replace my helmet?”' Until now it has been difficult to find any reliable figures to help answer these queries. MET have now developed a series of tests which are conducted on aged helmets to determine a 'best before' date (unless the helmet is involved in an accident. In that case it should be replaced immediately.). The results indicate that, if used properly accordingly to our owner manual, our helmets will still do their job up to eight years after they have been made. Not only is that good news for the customer, it’s great news for the environment!"

We applaud MET for undertaking an actual testing program on helmet life and for making that statement. We regard it as a triumph of integrity over marketing. MET's helmets are made with industry standard shells and liners, so there is no reason we can see that their recommendation should not be good for many other helmet brands as well. If another manufacturer comes up with a testing program that shows earlier deterioration in the protection from their products we will review this page.

In sum, we don't find the case for replacing a helmet that meets the ASTM or Snell standards that compelling if the helmet is still in good shape and fits you well.

[Catrin]

This is an interesting discussion. Not being material scientists does make it difficult to separate the wheat from the chaff. It is my personal opinion that it is better to be safe than sorry. Helmets aren't that expensive...

I used to think that having one helmet was enough, but after thinking about it, I decided to have two helmets (one for road and one for mountain biking). I figure that, if nothing else, switching them out extends their lives and should something happen to one of them that I still have one.

What I've not been able to settle is the question of possible damage to the helmet when it falls from a height when it isn't on my head - like from the trunk to the ground. Does that cause damage to the helmet? I've been to different sites but there appears to be mixed opinion on this one. So I don't put it on my trunk or top of my car these days, just in case.

[goldfinch]

This is an interesting discussion. Not being material scientists does make it difficult to separate the wheat from the chaff. It is my personal opinion that it is better to be safe than sorry. Helmets aren't that expensive...

I used to think that having one helmet was enough, but after thinking about it, I decided to have two helmets (one for road and one for mountain biking). I figure that, if nothing else, switching them out extends their lives and should something happen to one of them that I still have one.

What I've not been able to settle is the question of possible damage to the helmet when it falls from a height when it isn't on my head - like from the trunk to the ground. Does that cause damage to the helmet? I've been to different sites but there appears to be mixed opinion on this one. So I don't put it on my trunk or top of my car these days, just in case.

I've gone to two helmets too. I bought a new Bern, which is nice for tooling around town and for cooler weather. An upside is that it is the most comfortable helmet I have ever worn.

I used to ride motorcycles and the same discussion would come up on dropping your helmet and how much damage it causes. Some would say replace immediately! But I never new anyone who actually did that. It would be nice to have more data on that. I do as you do and try to put my helmet in a place where it isn't going to be tumbling down.