bike helmets

[Honey693]

I'm assuming bike helmets expire just like car seats.  How long are they good for?  Our helmets all have the manufacture date, but no expiration issue and I tossed the booklet that came with them.

[tibris]

avid cyclist here :) What I have always heard is you should replace it every 3 years or so. Not a strict deadline, but if you use it a lot (like multiple times a week), that is what I've been told.

[LaughingHyena]

I have read 5 years as a guideline in several places. Also replace if the shell is cracked or faded as that would suggest the plastic is breaking down.

As far as I know the main reason you need to replace (apart form a crash obviously) is that the plastic will break down over time so even helmets that have not been used much would not be as safe.

[tibris]

There is a difference between a helmet that is worn often and not. You don't realize the compression change in a well loved helmet till you have to replace it :) the foam on the inside conforms to your head and I'm sure all the sweat can't be good for it :p

[LaughingHyena]

I hadn't though about the foam compressing with regular use, that makes sense.

[tibris]

I hadn't thought of it either, but I had to replace mine a couple weeks ago due to a crash. Not a single helmet felt as good as my old one! They all jabbed my head in one way or another. Even the exact same brand/model.

[Spirit Dancer]

OK I have a question that has been on my mind for awhile. I have read in numerous sources that it takes about 100 years for a plastic grocery bag to completely decompose and even longer for a disposible diaper. This is even if they are in the damp earth. Yet, supposedly after only 5 years a helmet (or carseat) which is made of much thicker plastic may have already started to decompose (even when they have usually been kept mostly dry)?!  This makes no logical sense to me. Where do these number for carseat and bike helmet expiry dates come from? (I sometimes think it is just a play to get more sales). I once saw ONE video of a stimulated car crash where a carseat like 15 years old gave way in the strap slots in the crash. But this hardly proves anything if it is the only "evidance". 

Anyone have any ideas?

[tibris]

That's a good question! I've always wondered the same thing, if it's just to get sales. I think the car seat thing probably has more to do with advancing technology, most car seats now are safer than those 10 years ago, and well beyond those 15 years ago. As for helmets, I can attest to wear and tear on those, but they often see rain, tons of sweat, heat, etc. So I don't know. I know it doesn't take a grocery bag 100 years to decompose from my own back yard, a year or so, yes, and there may be a strip or two left, but it is mostly gone. At any rate, not sure, but I agree seems odd doesn't it? Anyone else have ideas?

[Honey693]

Originally Posted by tibris 

That's a good question! I've always wondered the same thing, if it's just to get sales. I think the car seat thing probably has more to do with advancing technology, most car seats now are safer than those 10 years ago, and well beyond those 15 years ago. As for helmets, I can attest to wear and tear on those, but they often see rain, tons of sweat, heat, etc. So I don't know. I know it doesn't take a grocery bag 100 years to decompose from my own back yard, a year or so, yes, and there may be a strip or two left, but it is mostly gone. At any rate, not sure, but I agree seems odd doesn't it? Anyone else have ideas?

I thought it had to do with the styrafoam (sp?) and how it starts to break down.  It seems to crumble faster when it's older.

[LaughingHyena]

Some more reading around and I cam across this site http://www.bhsi.org/replace.htm on when to replace a helmet. It goes through a few old designs and why the would be best replaced but does not give a time otherwise.

I though this was interesting

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!"

but I couldn't find anything on their (presumably now 2011) website.

Still maybe I'll hang onto mine a bit longer since it is made by them.

[tibris]

honey - there isn't much styrofoam in my carseats (britax marathons). Not to mention in mine the styrofoam is removeable, so why not just sell replacement styrofoam if that is the case? Just spit balling here, I definately don't know what i'm talking about :)

[Honey693]

Originally Posted by tibris 

honey - there isn't much styrofoam in my carseats (britax marathons). Not to mention in mine the styrofoam is removeable, so why not just sell replacement styrofoam if that is the case? Just spit balling here, I definately don't know what i'm talking about :)

I don't know what I'm talking about either, that was just my theory b/c DD1's Scenera seems to have a lot of foam.

[Spirit Dancer]

So according to this site it takes a plastic bag 10 to 20 years to biodegrade. And MUCH longer for styrofoam. http://www.thatdanny.com/2008/06/06/how-long-does-it-take-a-plastic-bag-or-a-glass-bottle-to-decompose/

And a plastic bag is much, MUCH thinner then a carseat or helemt. I am just sick of consumerism and are the time limits for these products (especially carseats as they cost $$$) based on actual scientific evidance or just a way to get parents miney (in the name of safety). Maybe I am a bit odd to think about these things... :)

[DahliaRW]

Originally Posted by Spirit Dancer 

So according to this site it takes a plastic bag 10 to 20 years to biodegrade. And MUCH longer for styrofoam. http://www.thatdanny.com/2008/06/06/how-long-does-it-take-a-plastic-bag-or-a-glass-bottle-to-decompose/

And a plastic bag is much, MUCH thinner then a carseat or helemt. I am just sick of consumerism and are the time limits for these products (especially carseats as they cost $$$) based on actual scientific evidance or just a way to get parents miney (in the name of safety). Maybe I am a bit odd to think about these things... :)

Completely biodegrading is not the same as becoming brittle and failing.  That is the issue with plastics in car seats (and probably helmets too).  Over time with exposure to extreme temps the plastic STARTS to break down (yes, a bag may not completely biodegrade for 10-20 years, but it starts to get wear spots and holes prior to that.  The blastic starting to break down causes it to brittle, which makes it easier to break.  And, in a car crash where tons of force is being put on the seat an old seat with brittle plastic could fail as in crack or break apart in a way not inteded (i.e. the harness ripping out, the top part breaking off into shards and cutting your child, etc).

[Spirit Dancer]

Originally Posted by DahliaRW 

Completely biodegrading is not the same as becoming brittle and failing.  That is the issue with plastics in car seats (and probably helmets too).  Over time with exposure to extreme temps the plastic STARTS to break down (yes, a bag may not completely biodegrade for 10-20 years, but it starts to get wear spots and holes prior to that.  The blastic starting to break down causes it to brittle, which makes it easier to break.  And, in a car crash where tons of force is being put on the seat an old seat with brittle plastic could fail as in crack or break apart in a way not inteded (i.e. the harness ripping out, the top part breaking off into shards and cutting your child, etc).

Yes, I know this but where is the evidance that after five years this starts to happen? That is the info I am looking for. What is it is more like 25 years

before it does- would save a lot of $$$.

[DahliaRW]

Originally Posted by Spirit Dancer 

Yes, I know this but where is the evidance that after five years this starts to happen? That is the info I am looking for. What is it is more like 25 years

before it does- would save a lot of $$$.

Well, most seats are 6-8 years, depending.  Only one that I know of is 5 years.  We do know the harness ripped out of a britax seat in a crash test after 10 years, so 25 is very unlikely.  Car seat manufacturers are going to want a safe margin of error.  If they say 10 years, and the plastic brittles and fails at 9 1/2 they can be sued and are liable.  If they say 8 and it fails at 9 then the seat is being misused and they are not liable.  I believe they also are playing to worst case scenerio (extreme temps and climate) to play it safe.

Now, would I possibly use a seat a few months past it's expiration if I was saving up for a new one and couldn't quite swing it, maybe.  Would I use it years past expiration, no.  It's just not worth the risk.  If I did that and the seat failed in an accident I'd be really upset that my child go hurt or died so I could save a few dollars.  Not a risk worth taking.

 

[TheGirls]

Originally Posted by Spirit Dancer 

Yes, I know this but where is the evidance that after five years this starts to happen? That is the info I am looking for. What is it is more like 25 years

before it does- would save a lot of $$$.

The more important question - where is the evidence that this doesn't happen after 5 years?  The manufacturers ran their tests, and decided on their limits (6-8 years for most carseats), and as far as I know no one else has tested it.  I'm not personally willing to test it with my child, so I'm going to go with the manufacturer's expiration date, even if it's probably a little conservative. 

That said, I've bought seats that are more like 15 years old at garage sales (I trade them in at the BRU event, I don't use them!) and they already feel very brittle and sometimes pieces break off in the trunk of my car on the way home.  Given that a crash has a LOT more force than just rattling around in my trunk, I think that 6-8 years seems fairly within the realm of reasonable.  There was a crash test a few years ago of a 10yo Britax seat where the harness ripped out as if the seat was made of paper - after only 10 years.   It wouldn't shock me if the manufacturers are expiring seats a little bit too early, and being a bit conservative (both for liability and profit motivations), but given that we know 10 years is too long and I've seen that 15 years is WAY too long, I don't think that they are being outrageous. 
 

[LaughingHyena]

Interestingly I've never seen a car seat in the UK with an expiry date. I vaguely remember someone here ringing Britax UK and being told we don't have expiry dates here. I have seen plenty of advice not to use unknown second hand seats or ones over 10 years old but nothing else.

I suppose we don't have as many extremes of temperature as the US but plastic must still break down here too.It makes me wonder how much science and how much cultural expectations play into the expiry dates. I'm sure there must be a bit of both.

[savithny]

Originally Posted by Spirit Dancer 

Yes, I know this but where is the evidance that after five years this starts to happen? That is the info I am looking for. What is it is more like 25 years

before it does- would save a lot of $$$.

I'm pretty sure from my own experience it's a lot less than 25 years, even if its more than 5.   Stuff my parents stored in their attic has noticeably changed in color and flexibility in only 8-10 years.

My best friend is a Materials Science Engineer.   One of the things she does is test rubber and plastic car parts, and one of the tests they do is to artificially age those parts to duplicate long-term use, to see how well the parts wear under use, when they're heated and cooled over and over.   Manufacturers really do know a lot about how specific materials behave over time and with exposure to heat and sunlight.    I really don't think that expiration dates are just made up to sell more seats, given what I've heard her and her colleagues say about how they study their products.   The dates might be somewhat conservative, but I believe they are probably based on actual research data.

 And also remember that if they say "Sure, it's fine for 10 years!"  someone is going to leave it in a car for 10 years straight in the Arizona desert and then get in an accident and sue them when the carseat shatters into child-stabbing shards.
 

[savithny]

Video of a Britax coming apart during a crash test at 10 years.

Note its embedded in a thread of carseat technicians dicsussion how valid the video is, in case you think the same "why should I care" sort of thoughts.

http://www.car-seat.org/showthread.php?t=126838