Question Expiration dates

U

Unregistered

Guest
I am trying to locate data on safety seat expirations. Specifically, I am interested in studies used to determine the lifespan of materials and components in child safety seats. Is anybody aware of any publicly-available data? To be clear: I'm not looking for manufacturer declarations that a seat expires after X years. I am looking for the data upon which that decision is made. Many thanks for any input!
 
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MelodyoftheForest

Active member
I am sure the data would not be general to all seats and manufacturers, but very specific. There are many materials and configurations out there. You might be able to find some general information on how plastics and metals are tested, though. My husband is an engineer and I'm pretty sure he has a whole textbook on materials testing. Is there a specific reason you are curious?
 

ketchupqueen

CPST and ketchup snob
Staff member
Yes, different manufacturers use different components for different seats. They get their materials tolerance data from the suppliers, do their own endurance testing, and based on all that combined data choose an expiration date with a margin of error that accounts for differing climates, usages, etc.
 
U

Unregistered

Guest
Yes, different manufacturers use different components for different seats. They get their materials tolerance data from the suppliers, do their own endurance testing, and based on all that combined data choose an expiration date with a margin of error that accounts for differing climates, usages, etc.


Thanks for the reply. But it doesn't really answer my question --- is there any data or peer reviewed studies that demonstrate that these expiration dates are scientifically valid and have any effect on child injuries and fatalities? That seems unlikely, no? Automobile safety systems also are made from multiple materials sourced from many different suppliers ... and I've never seen Ford or GM announce that - sorry! - your seatbelt safety system just expired. Cut it up, write "EXPIRED" in big block letters, and throw it away.

So again - is there any documentation that supports these expiration dates?
 

wendytthomas

Admin - CPST Instructor
Staff member
Besides the manuals for the carseats, which are based upon years of research and development by the carseat manufacturers? They do the testing, and based on their testing they determine the length of the lifespan for each seat.

There isn't a part of your car that's mission critical that's totally made of plastic, like on a carseat. Your seatbelt is made of nylon and metal bits. Your carseat is made of plastic, nylon, and fabric, with the plastic being the weak part (ever sit on a lawn chair that's been outside too many years?).

Wendy
 
U

Unregistered

Guest
No need to get hostile, Wendy. All I'm asking is: where is the data? Where are the studies? A manual isn't a study. It isn't data. It doesn't prove anything.

The answers presented here are all of the deductive variety: seats are made of plastic; plastic degrades over time; thus seats degrade over time; thus, seats expire at six years. Surely, someone, somewhere, has gathered the actual data to show that this deduction is actually something more than theory.

Wendy, you say they do testing. I hope so! Can you point to the testing that confirms or validates the expiration dates? Several companies put crash test videos and other testing online ... but nothing related to expiration, so far as I can find. Why? Or am I missing it?
 

wendytthomas

Admin - CPST Instructor
Staff member
The answers presented here are all of the deductive variety: seats are made of plastic; plastic degrades over time; thus seats degrade over time; thus, seats expire at six years. Surely, someone, somewhere, has gathered the actual data to show that this deduction is actually something more than theory.

They don't all expire at six years. Some are four, some are 12. There's a range. It depends on what the company has decided based on their testing.

Wendy, you say they do testing. I hope so! Can you point to the testing that confirms or validates the expiration dates? Several companies put crash test videos and other testing online ... but nothing related to expiration, so far as I can find. Why? Or am I missing it?

I've seen it in progress with my own eyes (been to the manufacturing plant of one, saw the seats being made, saw them doing their ongoing testing, got to see a crash test). But they don't release their data, no. The results of their data are in the manuals.

Have you called them to ask for it?

Wendy
 
U

Unregistered

Guest
Hi Wendy --- Thanks again for the reply. You seem super knowledgeable about this topic. But, alas, I haven't been able to get an answer to my question: where are the studies? The data? Manuals, for all of their advantages, aren't the results of studies. And I'm still looking for information on the scientific and engineering basis for expiration dates. Now, to be fair, the car seat manufacturers aren't required to make those studies. As I'm sure you know, the NHTSA doesn't have rules or regulations governing car seat lifespans. For whatever reason, the federal govt doesn't think car seat expirations are worth regulating. But, perhaps, the car seat manufacturers do. Anyway, I'll keep looking. Thanks for your input!
 

jjordan

Moderator
I think you have your answers. Manufacturers do their own studies at their own facilities and don't publish their data. Hence, what you are asking for is not readily available. As Wendy said, calling the manufacturer of a particular seat might get you to someone who can discuss data for that particular seat.

You can probably track down data/studies for particular components. For instance seat belt webbing has been extensively studied. (However, car seat straps are not exactly the same as seat belt webbing.) I am sure that various types of plastics have been studied as well. (But again, we don't know what exact kind of plastic is used in what seat or what exact forces it is subject to etc.)

To your point of car manufacturers not having expiration dates on their components, that is not entirely true in the sense that car manuals do have recommended maintenance schedules. For instance most vehicles say to replace the timing belt (if there is one) at 100k miles. So that can be considered an expiration date for the timing belt. Also most vehicles tell you exactly when to have your airbag system inspected (for our Subaru it says 10 years after manufacture). I think that if you check a vehicle manual you'll find that many parts do have "expiration" dates, they're just not called that, exactly.
 
S

Skeptic

Guest
I think you have your answers. Manufacturers do their own studies at their own facilities and don't publish their data. Hence, what you are asking for is not readily available. As Wendy said, calling the manufacturer of a particular seat might get you to someone who can discuss data for that particular seat.

You can probably track down data/studies for particular components. For instance seat belt webbing has been extensively studied. (However, car seat straps are not exactly the same as seat belt webbing.) I am sure that various types of plastics have been studied as well. (But again, we don't know what exact kind of plastic is used in what seat or what exact forces it is subject to etc.)

To your point of car manufacturers not having expiration dates on their components, that is not entirely true in the sense that car manuals do have recommended maintenance schedules. For instance most vehicles say to replace the timing belt (if there is one) at 100k miles. So that can be considered an expiration date for the timing belt. Also most vehicles tell you exactly when to have your airbag system inspected (for our Subaru it says 10 years after manufacture). I think that if you check a vehicle manual you'll find that many parts do have "expiration" dates, they're just not called that, exactly.



In other words: neither you nor anyone else on this forum has any idea as to whether or not there's an actual research basis - data, mfr studies, etc - for expiration dates. It's taken on faith.
 

wendytthomas

Admin - CPST Instructor
Staff member
I think you missed the part where I've seen them doing their testing for their research with my own eyes.

Now, whether or not you believe me? You're asking for our help, with the understanding that what we say may sway you.

They do quality control testing for X number of uses. It breaks after some thousands of repetitions. They know what that average number is, based on environmental issues, child use (soda poured over it once a month! Sure, let's test that), parental fat fingers, etc. Based on that, they've declared their expiration date.

So yes, they completely have, highly controlled experimental and testing situations.

It sounds like you don't want to believe it. Ok, up to you. Replace your seats more often than necessary, since otherwise you're using your child to do your own testing, which is not recommended. I guess I'm just not seeing the downside of replacing a seat when you can probably go through the carseat life of your child (about 13 years) paying $300 total if you shop well. $100 at birth, $100 to go from about one to six years old, and $100 for a booster for the last several years. You never run into expiration dates, assuming one child is using the seat there, since your child will make a change to the next stage anyway before it would happen. You don't have a seat that's five years old and looking like a good fire would be the best way to clean it anymore after that, too.

Wendy
 

SafeDad

CPSDarren - Admin
Staff member
In other words: neither you nor anyone else on this forum has any idea as to whether or not there's an actual research basis - data, mfr studies, etc - for expiration dates. It's taken on faith.

It's no different than any critical safety product. Materials degrade. Temperature cycles are a main factor for automotive applications. Exposure to solar radiation, vibration, oxidation and other factors can be factors also. Plastics, rubber and even metals weaken over time. As they say in the auto industry, your mileage may vary. There is no exact cutoff date. Manufacturers certainly do testing and have decades of experience with products and then presumably assign a reasonably conservative lifespan to protect consumers from harm and themselves from litigation. Most of this testing is proprietary, also likely for legal reasons but also for competitive purposes. Beyond material issues there are also reasons pertaining to increasing likelihood over time of missing labels, missing parts or simply becoming significantly inferior to new products at some point. If an individual consumer wants to dismiss manufacturer recommendations, that is up to them, of course. Obviously, do so at your own risk.

https://www.nbcchicago.com/news/loc...bout-Car-Seat-Expiration-Dates-319101621.html

I think if you are genuinely interested, you can find studies on material degradation over time, even specific to polypropylene (ICS or EPP), polystyrene (EPS) and polyethylene (HDPE/LDPE) that is often used in car seats. Finding it specific to an entire system or product like an automobile seatbelt system, carseat or other product is much more difficult. Even if you found one, I doubt it would be convincing to you if your intent is to exceed the suggested expiration date. We do not represent manufacturers here and do not have access to their research, so if you own a specific carseat, you can contact that manufacturer directly if you have specific questions.
 

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