Author Topic: why the five year life span on helmets?  (Read 17763 times)

canuguzzi

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Re: why the five year life span on helmets?
« Reply #30 on: October 03, 2015, 10:10:22 AM »
One reason, and there are several is that the helmet spends a great deal if time in the sun and the UV attacks the outer shell. We have all seen what a lotnof exposure to the sun can do to many materials, even those that are claimed to be UV resistant. Very few man made materials are UV proof so after time they degrade.

Plastics, composites and such all degrade with time. The time limits helmet makers put on their wares is aligned with predicted rates of degradation so that you know when a helmet could be considered less than optimum at protecting your noggen.

Some people will choose to decide for themselves when a helmet isn't really suited to perform as they have better testing procedures, know more and the tin foil liners theybuse are so much better than what the engineers know and use.

Offline boatdetective

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Re: why the five year life span on helmets?
« Reply #31 on: October 03, 2015, 10:17:33 AM »
One reason, and there are several is that the helmet spends a great deal if time in the sun and the UV attacks the outer shell. We have all seen what a lotnof exposure to the sun can do to many materials, even those that are claimed to be UV resistant. Very few man made materials are UV proof so after time they degrade.

Plastics, composites and such all degrade with time. The time limits helmet makers put on their wares is aligned with predicted rates of degradation so that you know when a helmet could be considered less than optimum at protecting your noggen.

Some people will choose to decide for themselves when a helmet isn't really suited to perform as they have better testing procedures, know more and the tin foil liners theybuse are so much better than what the engineers know and use.

This is a blanket statement and just isn't based on demonstrable evidence. Once again, I know I come off as a jerk when I say it, but my job is assessing failure of composites on boats. The theory that all fiberglass composites gradually degrade just does not hold water.
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Offline MGPilot

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Re: why the five year life span on helmets?
« Reply #32 on: October 03, 2015, 10:26:46 AM »
Isn't the concern about the impact absorbing liner, ...

^^^^^  This.

The issue is that the helmet can appear new, but the liner not only hardens but shrinks over time.

This creates a situation where your head (whether you value it or not) will encounter 2 impacts in an accident.

Just like for a helmet that's too large, the first is when the shell hits the object, the second is when your head hits a liner. And in this case, the liner is harder and less absorbent than it was when the helmet was new.

Has nothing to do with UV or how you've used or not used the helmet. Simply out-gassing of volatiles that keep the materials flexible.

That's why, in particular, clubs with track days won't let you use a helmet that's over 5 years old.  Can you continue to use it on your own....of course.  That the deceptive part is, the helmet probably feels more comfortable than it did when you bought it. 

Your choice.
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Offline Triple Jim

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Re: why the five year life span on helmets?
« Reply #33 on: October 03, 2015, 10:37:45 AM »
That's why, in particular, clubs with track days won't let you use a helmet that's over 5 years old.

Of course it could also be the legal liability thing again.
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Re: why the five year life span on helmets?
« Reply #33 on: October 03, 2015, 10:37:45 AM »

Offline MGPilot

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Re: why the five year life span on helmets?
« Reply #34 on: October 03, 2015, 10:56:59 AM »
Of course it could also be the legal liability thing again.

Absolutely, it is the legal liability if they knowingly let you use helmets for their track days that can increase your chance of injury.  And of course, it's NOT the guys who don't have an accident. It's the family of the deceased or the paraplegic that are looking for compensation.

I belong to the local Porsche Club. We haggled over this quite a while. On one hand, we didn't want to force people to go out to get a new helmet when their Snell approved helmet may only have been used a few times over the past years.

On the other hand, we had an obligation to our members to create safe track days and keep our insurance premiums for those events affordable.

The evidence was pretty clear.

But....note that suddenly at 5 years, the helmet will not become dangerous.

What they're saying is that a helmet can be expected to perform like new for at least 5 years. After that time, protection starts to deteriorate.  But, clearly it's a gradual thing--faster for some brands and construction materials than others, faster for some usage than others, etc.

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Offline Testarossa

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Re: why the five year life span on helmets?
« Reply #35 on: October 03, 2015, 11:23:31 AM »
Fiberglass is forever. Polycarbonate may not be. But the weak link is the EPS liner. When I moved last year, cleaning out the garage uncovered three ancient helmets -- my Bell 500 and Star and an old Shoei -- all 20 to 30 years old. As soon as I lifted, them, the liners turned to a chunky black powder that ran out onto the floor.

That's not going to happen in five years, of course, but the process begins sometime around the decade mark.

Helmets aren't the only time-limited safety equipment. The ski industry has a five-year limit on ski bindings -- beyond that, manufacturers won't indemnify retailers targeted by personal injury suits.  Insurers don't want the long liability tail. So no shop will test or service bindings that aren't on the five-year indemnification list.
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Offline Toystoretom

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Re: why the five year life span on helmets?
« Reply #36 on: October 03, 2015, 11:38:45 AM »
Your head shrinks 1% a year. After 5 years your helmet is too loose. At age 100 all you have is ears and a nose.

redrider

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Re: why the five year life span on helmets?
« Reply #37 on: October 03, 2015, 11:40:13 AM »
"I wouldn't compare bicycle helmets because possible impact forces should be dramatically lower."

Drop testing helmets simulates the vertical impact forces from a fall. I'm sure a 20 pound head form does not relate well to an entire 200 pound pile driver. Those  tests do not measure hitting the wall at 100 whatever.

oldbike54

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Re: why the five year life span on helmets?
« Reply #38 on: October 03, 2015, 11:59:28 AM »
 Something to factor in , most of us old guys are so hard headed that a THIRTY year old helmet would probably suffice  :shocked:

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Offline normzone

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Re: why the five year life span on helmets?
« Reply #39 on: October 03, 2015, 12:42:09 PM »
Fiberglass is forever. Polycarbonate may not be. But the weak link is the EPS liner. When I moved last year, cleaning out the garage uncovered three ancient helmets -- my Bell 500 and Star and an old Shoei -- all 20 to 30 years old. As soon as I lifted, them, the liners turned to a chunky black powder that ran out onto the floor.

That's not going to happen in five years, of course, but the process begins sometime around the decade mark.

Helmets aren't the only time-limited safety equipment. The ski industry has a five-year limit on ski bindings -- beyond that, manufacturers won't indemnify retailers targeted by personal injury suits.  Insurers don't want the long liability tail. So no shop will test or service bindings that aren't on the five-year indemnification list.
  Makes sense to me. My first Shoei, new in ...1985 ? was just fine through circa 2005, then the lining magically shredded itself, and came out in little fragments.
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Offline Two Checks

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Re: why the five year life span on helmets?
« Reply #40 on: October 03, 2015, 02:32:02 PM »
If you helmet was as over designed as a boat hull, it would be too heavy to wear. <shrug>
But it's still fiberglass and it aint the fiberglass that deteriorates.

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Offline Sasquatch Jim

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Re: why the five year life span on helmets?
« Reply #41 on: October 03, 2015, 02:35:32 PM »
 As I see it the 5 year life span on helmets is due to two reasons, to sell more helmets and because by then the old one stinks.
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Offline Rich A

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Re: why the five year life span on helmets?
« Reply #42 on: October 03, 2015, 02:37:59 PM »
As I see it the 5 year life span on helmets is due to two reasons, to sell more helmets and because by then the old one stinks.

True--after 5 yrs my helmets are pretty funky. And I bathe regularly, often wear a do-rag or something between it and my head, esp on longer rides, etc.

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canuguzzi

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Re: why the five year life span on helmets?
« Reply #43 on: October 03, 2015, 02:49:21 PM »
This is a blanket statement and just isn't based on demonstrable evidence. Once again, I know I come off as a jerk when I say it, but my job is assessing failure of composites on boats. The theory that all fiberglass composites gradually degrade just does not hold water.

All materials degrade over time. That banket statement is beyond question.

You're just relaying your experience and knowledge which is fine. The length of time it takes materials tondegrade varies but they all do without exception. Some may take a long time to degrade but motorcycle helmets are made of a variety of materials, nylon web straps, soft touch plastics and so on. They all degrade.


Offline jackson

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Re: why the five year life span on helmets?
« Reply #44 on: October 03, 2015, 02:49:24 PM »
For the last 25+ years, I have always worn a cotton or silk cover that covers all of my hair and the portion of my forehead that touches the helmet padding.  Then, I wash those covers after every 3-4 rides so they can't get funky.  My present helmet (Aria) has been used for around four years and looks brand new on the inside/has no smell, etc. due to always wearing the head cover.  Good helmets are not cheap and doing this will extend the life of the padding from sweat and hair oil, etc.
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Offline MGPilot

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Re: why the five year life span on helmets?
« Reply #45 on: October 03, 2015, 03:38:51 PM »
For the last 25+ years, I have always worn a cotton or silk cover...

These seem well made and stand up to regular washing. Not the cheapest.
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canuguzzi

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Re: why the five year life span on helmets?
« Reply #46 on: October 03, 2015, 08:04:48 PM »
  Makes sense to me. My first Shoei, new in ...1985 ? was just fine through circa 2005, then the lining magically shredded itself, and came out in little fragments.

Proof the 5 year advisement doesn't sell more helmets.

Penderic

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Re: why the five year life span on helmets?
« Reply #47 on: October 03, 2015, 08:20:28 PM »
Older helmets tend to rattle more, for some reason ....

 :grin:
« Last Edit: October 03, 2015, 08:21:13 PM by Penderic »

Offcamber1

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Re: why the five year life span on helmets?
« Reply #48 on: October 03, 2015, 08:36:38 PM »
Pitch them after you have an accident.

Maybe the assumption is that on average, a motorcyclist has a crash every 5 years?

Offline Arizona Wayne

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Re: why the five year life span on helmets?
« Reply #49 on: October 03, 2015, 09:18:06 PM »
Pitch them after you have an accident.

Maybe the assumption is that on average, a motorcyclist has a crash every 5 years?




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Offline HDGoose

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Re: why the five year life span on helmets?
« Reply #50 on: October 03, 2015, 09:48:38 PM »
1) fiberglass (as well as many other things) never stops curing. It only slows down.

2) in 5 years, or less, I usually find that the lining and styrofoam now longer allow a good fit on my head.

 

Offline Triple Jim

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Re: why the five year life span on helmets?
« Reply #51 on: October 03, 2015, 11:42:26 PM »
I keep them for the memories........... ... :boozing:

Funny... I still have a '70s Electro helmet with scrapes on the top of it from when I did a front flip with my H2 and slid in the gravel on my head.

There have been several posts about fiberglass that refer to it as if it's impervious, or it doesn't stop curing, or it does or doesn't degrade in sunlight.  In reality fiberglass is... glass.  It can be made into a laminate with epoxy, polyester, or many other binding agents.  Its longevity is very dependent on that agent, since glass itself isn't likely to degrade in our lifetimes.  Unless you specify the finished laminate, like G10 or FR4, for example, the term "fiberglass" in itself is relatively meaningless.
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Offline charlie b

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Re: why the five year life span on helmets?
« Reply #52 on: October 04, 2015, 08:52:25 AM »
Took this directly from the UK Arai site as my RX-7 Corsair is now 8 years old and I wanted to know when I should start looking for a replacement.

Arai helmets are handmade to the highest possible standard, and although after many years the outside shell can look as good as new, it�s the EPS polystyrene liner that loses its ability to absorb impact over time. Arai recommend replacing your helmet 7 years after date of manufacture and 5 years after date of purchase to maintain the maximum levels of protection.The EPS liner is effectively the shock absorber of your helmet, absorbing the force of an impact onto the shell. This is done by the cells in the poly styrene being expanded (EPS = Expanded Polystyrene) and filled with air to absorb impacts. Over time, even when not in use, these liners lose their air pockets incrementally, after 7 years, dropping the shock absorbing ability of the liner below Arai�s safety standards. This is why we declare the helmet due for replacement so it can properly protect you against impacts.

This is what I suspected was the part that is the issue.

So, why can't I buy a $20 replacement liner for my helmet and keep the shell?

If Schuberth would do that I'd go buy one in a heartbeat, or any other very expensive helmet out there.

Seems a shame to throw away a perfectly good helmet just because some cheap 'packing foam' degrades over time.
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Re: why the five year life span on helmets?
« Reply #53 on: October 04, 2015, 02:33:45 PM »
The above statement is correct. styrofoam drys out over time and loses it shock absorbent properties. Left long enough it will crumble. I have seen this firsthand with an old helmet from my twenties that I kept around for sentimental reasons.
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Offline Sasquatch Jim

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Re: why the five year life span on helmets?
« Reply #54 on: October 04, 2015, 02:40:21 PM »
 For some reason a helmet always fits looser after a visit to a psychiatrist.
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Offline Arizona Wayne

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Re: why the five year life span on helmets?
« Reply #55 on: October 04, 2015, 06:44:40 PM »
This is what I suspected was the part that is the issue.

So, why can't I buy a $20 replacement liner for my helmet and keep the shell?

If Schuberth would do that I'd go buy one in a heartbeat, or any other very expensive helmet out there.

Seems a shame to throw away a perfectly good helmet just because some cheap 'packing foam' degrades over time.







Some brand helmets will sell you a new inside foam replacement, but I don't know for how long.

Offline boatdetective

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Re: why the five year life span on helmets?
« Reply #56 on: October 04, 2015, 10:07:50 PM »
So, out of curiosity, I looked up the degradation of expanded polystyrene (styrofoam). The sources stated that polystyrene is chemically inert and so resistant to acids and bases ( so much for the body oil argument. It also went on to mention the environmental problem with its resistant to natural breakdown. That seems to have the ring of truth also.  If polystyrene just fades away, then there wouldn't be such a hue and cry about our overloaded landfills.

So far, science is lining up with the "this is BS " side of the fence.
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Offline Triple Jim

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Re: why the five year life span on helmets?
« Reply #57 on: October 04, 2015, 11:01:16 PM »
Your reasoning sounds good boatdetective.  Polystyrene will degrade with exposure to UV, but it's really not many hours, percentage-wise, that the completely covered styrofoam layer of a helmet sees UV.

If, in my judgement, my helmet feels about like it did when it was new, and pieces of foam aren't getting in my eyes, for example, I'll keep using it.  Others should do whatever they feel is appropriate for their own safety.
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Offline JayDee24ca

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Re: why the five year life span on helmets?
« Reply #58 on: October 04, 2015, 11:02:39 PM »
I'm still using my white 1976 Shoie full face helmet. The liner is still in good shape, as is the styrofoam, with no sign of decomposition or degradation. The outer shell is intact, with no chips, cracks, or visible signs of degradation. When not being worn, the helmet is kept out of the light and heat. It seems to fit me well. I get a lot of razzing from people, but I'm okay with that, and the perception of higher risk. It also bothers them that I still wear jeans and not full armoured drawers. I am also a real daredevil and sometimes ride with no gloves! (gasp)
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Re: why the five year life span on helmets?
« Reply #59 on: October 05, 2015, 03:11:16 AM »
Some reasons that might not be a good generalization:

1. Bicycle helmets have a lot of ventilation spaces, so the pressure (psi) on the materials for a given impact is higher than for motorcycle helmets.
2. While average riding speeds are lower for bicycles, downhill speeds can easily get over 40 mph.
3. With some accidents, the speed that the 2-wheeled vehicle is going may not matter as much as the speed the car that hit it was going.
4. Many motorcycle helmet impacts result from the rider's head hitting the pavement, when it's able to slide, rather than be stopped by something like a curb, so the impact in those cases is mainly a fall from six feet up.

I just made myself dizzy trying to read and understand the differences between DOT and Snell bicycle helmet and motorcycle helmet testing standards. I won't pretend I really got a full picture, but I'll say that there are whole sets of different standards, as we all know the final products are visibly dramatically different.

I stand by the gist of my comment that they probably shouldn't be compared when judging things like life span because they so different.

And though you make some good points that there is potential crossover in the possible range of forces they may encounter, I think you can easily agree there is much more potential for much higher forces in average motorcycle helmet use than bicycle.

Which is probably why there are such different designs, as well as standards for testing.
« Last Edit: October 05, 2015, 03:30:17 AM by Kev m »
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