User Tag List

Page 1 of 2 12 LastLast
Results 1 to 20 of 25

Thread: Helmets -- shelf life and useful life. Is there any actual data?

  1. #1
    Join Date
    Nov 2008
    Location
    Alexandria, VA
    Posts
    1,405
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Helmets -- shelf life and useful life. Is there any actual data?

    I know most manufacturers recommend replacing a helmet every three to five years due to UV degradation and other factors. Has there ever been a scientific study to test the integrity of helmets over time? I've bought helmets direct from the manufacturer that were almost three years old,so I'm assuming that this number only applies to outside usage and that a helmet sitting in a box doesn't "age." But I'm not 100% on that.

    So, is there any independent data out there that shows how long it is safe to use a helmet? I know that it's my head and it's important, etc. etc. etc. I just want to see if there is any research done into this.

    TIA

  2. #2
    Join Date
    Oct 2010
    Location
    Chappaqua, NY
    Posts
    3,283
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    While I disagree with Snell on many many things, sometime in the 90s or early 2000s, they tested a number of stored 20 year old motorcycle helmets against the original impact standard. As I recall it, they all passed with similar numbers to the original tests. I infer that there's no material degradation of EPS from human-scale passage of time. And BHSI did a test of sunscreens/DEET/gasonline applied to helmets, too (available on the web, here: Testing cosmetics for damage to helmets). Soaking the EPS in gasoline reduced impact performance (surprised?), but other solvents had no measurable impact.


    In short, replace when it gets grungy or out of fashion. Say, I think you'd look hawt in one of those Giro Air Attacks.
     

  3. #3
    Join Date
    Jun 2008
    Location
    Charlottesville
    Posts
    6,862
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    use your head
    "make the break"

  4. #4
    Join Date
    Apr 2010
    Location
    Alameda, CA
    Posts
    2,352
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    Quote Originally Posted by christian View Post
    While I disagree with Snell on many many things, sometime in the 90s or early 2000s, they tested a number of stored 20 year old motorcycle helmets against the original impact standard. As I recall it, they all passed with similar numbers to the original tests. I infer that there's no material degradation of EPS from human-scale passage of time. And BHSI did a test of sunscreens/DEET/gasonline applied to helmets, too (available on the web, here: Testing cosmetics for damage to helmets). Soaking the EPS in gasoline reduced impact performance (surprised?), but other solvents had no measurable impact.


    In short, replace when it gets grungy or out of fashion. Say, I think you'd look hawt in one of those Giro Air Attacks.
    Do you remember if that study took ultraviolet exposure into account?
    steve cortez

    FNG

  5. #5
    Join Date
    Oct 2010
    Location
    Chappaqua, NY
    Posts
    3,283
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    The SNELL one, AFAIK, did not. I think they just took old helmets out of boxes. But I think you can find sufficient uses of EPS in non-helmet environments to tell you that UV breakdown is not a major issue. Just as I wouldn't leave my helmet on the gas tank of my mc, I wouldn't place it upside down outside for ten years, but in regular usage, I don't think it's a major issue.

    An engineer friend of mine in a strictly regulated industry once said something like this: "Helmets expire because it isn't in the interest of helmet companies test degradation over time. Data doesn't exist for the same reason." He then said a bunch of shit about Arrhenius equations and stuff. I think the gist of it was that maybe 0.1% of helmets will degrade before 5 years and 98+% could last 25 years, and that it's purely a given number of acceptable failures pre-expiry and statistical conceit that comes up with the 5 year number. The vast majority of helmets will then last far far longer.

    If anyone has a NOS Specialized Piranha, hook a man up, yo!
     

  6. #6
    Join Date
    Nov 2008
    Location
    Alexandria, VA
    Posts
    1,405
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    Quote Originally Posted by christian View Post
    In short, replace when it gets grungy or out of fashion.
    This is pretty much what I do. I also usually use different (read cheaper) helmets for commuting, since they get banged up more (and replaced more often). I'm more wondering, in general, and when I see friends riding with occasionally used 8-10 year old helmets. Basically, are they safe with those helmets or is it NBD?

    Quote Originally Posted by zetroc View Post
    Do you remember if that study took ultraviolet exposure into account?
    Christian's link doesn't have anything about UV exposure, which is my main concern.

    EDIT:
    Quote Originally Posted by christian View Post
    An engineer friend of mine in a strictly regulated industry once said something like this: "Helmets expire because it isn't in the interest of helmet companies test degradation over time. Data doesn't exist for the same reason."
    This is the sad reality. Someone posted a link to an article about the new concussion-friendlier helmets in the helmet poll last week, and that was a key takeaway. You can't make anything "safer" or "better" because that can open you up to liability.

  7. #7
    Join Date
    Aug 2011
    Location
    Beechworth, VIC
    Posts
    1,952
    Post Thanks / Like
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    The functional part of the helmet is made from EPS (expanded polystyrene). Being an aromatic polymer, polystyrene is very UV sensitive: basically the UV attacks the chain structure which weakens the polymer. I haven't seen any testing data for helmets but I can tell you that EPS insulation on wine tanks exposed to strong Australian sunlight for 5 years is perceptibly degraded: the surface becomes "dusty" as the degraded polymer flakes off.

    The UV sensitivity of PS can be mitigated by adding UV stabilisers, I do not know whether the EPS used in helmets includes this. For want of better information, it is safe to assume that the overall properties of the formulations are balanced, so increasing one property, say UV resistance, entails reducing other properties, say strength. If you were a large company playing off making a helmet heavier for a given (mandated) performance level vs UV resistance which is A; not a selling point and B; reduces the rate at which products are re-purchased, what would you do? I thought so.
     

  8. #8
    Join Date
    Sep 2010
    Posts
    3,166
    Post Thanks / Like
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    I think an Australian study show helmets reduce head injury by about 1/2. If the helmet is going to help, I suspect, old, new, moldy, it wouldn't really matter. In the other half of head injuries, the helmet probably doesn't make any difference.
     

  9. #9
    Join Date
    Feb 2009
    Posts
    816
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    Quote Originally Posted by Mark Kelly View Post
    The functional part of the helmet is made from EPS (expanded polystyrene). Being an aromatic polymer, polystyrene is very UV sensitive: basically the UV attacks the chain structure which weakens the polymer. I haven't seen any testing data for helmets but I can tell you that EPS insulation on wine tanks exposed to strong Australian sunlight for 5 years is perceptibly degraded: the surface becomes "dusty" as the degraded polymer flakes off.

    The UV sensitivity of PS can be mitigated by adding UV stabilisers, I do not know whether the EPS used in helmets includes this. For want of better information, it is safe to assume that the overall properties of the formulations are balanced, so increasing one property, say UV resistance, entails reducing other properties, say strength. If you were a large company playing off making a helmet heavier for a given (mandated) performance level vs UV resistance which is A; not a selling point and B; reduces the rate at which products are re-purchased, what would you do? I thought so.
    I'll add that the bond between the shell and the foam is another function component. In addition to absorbing impact, the helmet's other job is to slide. The moment of failure of the bond between the shell and the foam is a neck breaker when the helmet is sliding along the ground. This was the reasoning for the in-mold requirement of US sold helmets. Before that lots of shells were simply glued to the foam. The lifespan of the helmet must take into account the strength of the connection of these two elements.
     

  10. #10
    Join Date
    Jun 2008
    Location
    Cannon County TN
    Posts
    5,733
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    Hat should match the shooz. otherwise it's over-tinking.






  11. #11
    Join Date
    Jul 2008
    Location
    Oakland Ca
    Posts
    3,332
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    Been interested in whether sweat influences polystyrene life for years, finally decided to get off my ass and look it up:

    "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."

    from When to Replace a Helmet?

    Interested in what materials are being used in the concussion-reducing helmets...
    "Old and standing in the way of progress"

  12. #12
    Join Date
    Jun 2008
    Location
    Coquitlam, British Columbia
    Posts
    9,456
    Post Thanks / Like
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    Quote Originally Posted by cody.wms View Post
    Someone posted a link to an article about the new concussion-friendlier helmets in the helmet poll last week, and that was a key takeaway. You can't make anything "safer" or "better" because that can open you up to liability.
    The thing is, it's basically impossible to make any claims about helmet safety.
    Notice that bike helmet manufacturers don't make any claims about their product safety.

    You can't exactly test people's heads by smashing them into hard things, and seeing the results.
    And you can't even easily measure the forces of impact on the brain/skull because there are a
    million things a head could possibly hit in different ways.

    The fact that people think helmets offer significant protection is based on faith, not science.
    Good studies with a sound methodology to make claims don't exist.

    -g
     

  13. #13
    Join Date
    Oct 2010
    Location
    Chappaqua, NY
    Posts
    3,283
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    Quote Originally Posted by GrantM View Post
    Good studies with a sound methodology to make claims don't exist.
    Grant, what are your thoughts on the study of Ontario's helmet law published in Pediatrics Vol. 122 No. 3 September 1, 2008. While I don't support mandatory helmet laws for bicyclists (I think it reinforces cultural fear of an overwhelmingly safe activity), if one presumes that <16 yo helmet usage increased with the passage of the law, the fact that <16yo mortality figures changed and >16yo mortality figures remained the same appears potentially indicative of a public health benefit of helmet wearing.
     

  14. #14
    Join Date
    Jul 2008
    Location
    Oakland Ca
    Posts
    3,332
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    If a manufacturer can make a well-ventilated helmet that has been tested to reduce head velocity, that's a good enough standard to aim for. This tech looks promising: Building a safer football helmet – CNN Newsroom - CNN.com Blogs
    "Old and standing in the way of progress"

  15. #15
    Join Date
    Jun 2008
    Location
    Coquitlam, British Columbia
    Posts
    9,456
    Post Thanks / Like
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    Quote Originally Posted by christian View Post
    Grant, what are your thoughts on the study of Ontario's helmet law published in Pediatrics Vol. 122 No. 3 September 1, 2008. While I don't support mandatory helmet laws for bicyclists (I think it reinforces cultural fear of an overwhelmingly safe activity), if one presumes that <16 yo helmet usage increased with the passage of the law, the fact that <16yo mortality figures changed and >16yo mortality figures remained the same appears potentially indicative of a public health benefit of helmet wearing.
    I have some thoughts. Just looked at that study, since it's not one i've read before, but it has a similar methodology
    to many others. Firstly, there isn't any data to show that helmets are the cause of any change in mortality.
    Simply stating that mortality changed in a period where a helmet law was introduced isn't good science.

    They're assuming that a drop in injuries is related to helmet use. That's a big assumption.
    In the same period, pedestrian fatality dropped 60 percent. All road fatalities dropped in the period. Drinking and
    driving dropped. There needs to be a more rigorous examination of the context than just assuming cause and effect.

    Secondly, do helmet laws result in people wearing helmets? there isn't good data on actual helmet usage rates.
    This kind of data is often collected by self reported survey. So when they phone you and ask if you wear a helmet,
    people say yes, even when they don't really. Ontario has zero data on helmet law enforcement. There doesn't appear
    to be any, I see kids without helmets everyday, despite the law for under 18 to wear a helmet.

    Studies that look to the effects of helmet laws should not assume that helmets are being worn because it's the law.
    Case in point, the recent Corner's Review on Cycling fatalities found that despite the law in Ontario, 94% of of the
    youth who died did not wear a helmet. While very young children wear helmets at a high rate,
    only 32% of adolescent bike users wore helmets. (Page et al. 2012)

    This new study, out this week, a review of hospital records of cycling injuries across Canada found no statistical
    significance that helmet laws lead to a reduction in injuries. Maybe that's because the unenforced laws don't increase
    their use, or that helmets aren't that effective in reducing the severity of injury, and they're still in the hospital.

    http://www.calgaryherald.com/health/...121/story.html

    Page, Jessica L., Alison K. Macpherson, Tara Middaugh-Bonney, and Charles H. Tator. "Prevalence of helmet use by users of bicycles, push scooters, inline skates and skateboards in Toronto and the surrounding area in the absence of comprehensive legislation: an observational study." Injury Prevention 18, no. 2 (2012): 94-97.
     

  16. #16
    Join Date
    Jul 2009
    Location
    Near Los Angeles
    Posts
    1,280
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    I've cracked two helmets in crashes and replaced them. My current helmet started out red. Now it is pink and 8 years old. I've been lucky lately. Bell told me that they have tested helmets that were 8-10 years old and they passed. Whatever that means. They also suggested that helmets get replaced every 3-5 years. I'm pretty sure that my summer haircuts would be conversation starters had I not been wearing the ones that broke. I'm pretty sure that my 8 year old helmet will protect me as well as a new one. What is the p-value of Pretty Sure?
     

  17. #17
    Join Date
    Nov 2008
    Location
    OG sin city
    Posts
    1,048
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    as a TBI survivor I can not say much more than an in date helmet saved my life. I will buy a new helmet every 5 years, that said mine is now out of date I have not ridden yet this year money is tight and riding can wait until i have the funds to protect my self with proper in date gear.
     

  18. #18
    Join Date
    Jun 2008
    Location
    Coquitlam, British Columbia
    Posts
    9,456
    Post Thanks / Like
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    Quote Originally Posted by Bssc View Post
    I have not ridden yet this year money is tight and riding can wait until i have the funds to protect my self with proper in date gear.
    If you're not getting exercise, the behaviour of not riding is far riskier than riding.
    Being fit lowers your risk of all causes of death. Not doing anything is the same risk
    to your health as smoking 20 cigarettes a day. Watching TV and being on the computer
    is a far greater health risk than riding.

    -g
    Attached Images Attached Images
     

  19. #19
    Join Date
    Dec 2008
    Posts
    169
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    Here's a link to an article in Bicycling discussing MIPS helmets. Don't be put off by the fact that it's in Bicycling.
    http://www.bicycling.com/sites/defau...-13-Helmet.pdf
    Martin
     

  20. #20
    Join Date
    Jun 2008
    Location
    Coquitlam, British Columbia
    Posts
    9,456
    Post Thanks / Like
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Helmets -- shelf life and useful life. Is there any actual data?

    Quote Originally Posted by Martin T View Post
    Here's a link to an article in Bicycling discussing MIPS helmets. Don't be put off by the fact that it's in Bicycling.
    http://www.bicycling.com/sites/defau...-13-Helmet.pdf
    Martin
    thanks for posting this. Excellent article!!!!!
    One of the best pieces i've read that clearly differentiates
    what bike helmets do and don't protect.

    -g
     

Page 1 of 2 12 LastLast

Similar Threads

  1. Life insurance
    By Zimmermanbicycle in forum The OT
    Replies: 19
    Last Post: 10-13-2016, 09:55 AM
  2. Life Cycles...
    By onekgguy in forum General Discussion
    Replies: 0
    Last Post: 02-09-2013, 12:40 PM
  3. wtb: life ext butted st
    By anon. in forum The Path
    Replies: 0
    Last Post: 06-11-2011, 09:52 AM
  4. This if life
    By metanoize in forum The OT
    Replies: 6
    Last Post: 06-09-2011, 04:15 PM
  5. MAX-Life source?
    By anon. in forum The Path
    Replies: 2
    Last Post: 11-22-2010, 12:58 PM

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •