Information about FMVSS 213, ECE R 44, and Swedish "T" standard

[Adventuredad]

This was discussed in another thread where we discussed booster v. 5 pr. harness. I thought it might be interesting information for some. It's a summary of a conversation I had with an expert at a crash test facility. In case you have trouble sleeping some night, this summary will take care of it in less than a minute.....

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Someone asked the other day about the "T" standard and I have some more info. This ties into the whole discussion about booster and 5 pt. harness, a very interesting and educational discussion IMHO. We talked about ECE R 44 (Europe) and FMVSS 213 (US) and if they are the same.

There are similarities and differences between ECE R44, VVFS 2003:29 ("T" standard), and FMVSS 213 but it's not possible to say that one is better than the other. Basically, as someone mentioned earlier, in FMVSS 213 head is measured while it's not in ECE R 44. It is measured in the Swedish "T" standard. But it's not as simple as that.

In "T" (from now known as simply T because it takes too long to write....) all three directions of acceleration are measured. X, Y, and Z. These are used to calculate the resultant which should have an upper limit less than 500 m/s2. There is also an upper limit of Z which is 200 m/s2.

In FMVSS all three directions of acceleration are measured. These are used to calculate HIC (Head Injury Criteria) which has an upper limit of 1000 but there are no upper limits for Z acceleration or resultant.

In ECE R 44 there is no measuring of the head but all three directions of acceleration are measured in the chest. These are viewed as a good measure of what happens in the head, especially when it comes to Z acceleration. Experts say that Z acceleration in chest and head are more or less the same, therefore an upper limit of 30 G has been set in a positive direction (according to SAE 211). Some differences between this test and "T" are that the seats are crash tested from behind and also turned upside down in ECE R 44 and not in T. I also believe the fabric certification (material) is stricter (not sure about this last point)

Whatever standard is used, experts only looks at pass or fail. Not at how high over the limit a seat is. If one should figure out if a booster or a 5 pt. harness is better, one must measure them side by side. This would mean experts first agreeing on WHAT should be measures and what measures should be important. Lets say we want to measure HIC, then we need to do two identical tests with 5 pt. harness and booster. This would (hopefully) clear up what would be better (depending on terms set ahead of test) in this specific crash situation under these special circumstances.

It would not be enough with one test like this. A lot of different test would have to be made and compared side by side. Also, not to forget, experts would have to agree on what's the most important factors and place them on some kind of scale. For example, would a broken neck be better than a broken back? How much movement in the car by a booster would be good and what would be dangerous? Etc, etc. It would be somewhat subjective criteria which might vary depending on country/experts.

The T standard "expires" in May 2008 because countries which are in EU are not allowed to have national rules that are different than EU's rules.

One of the most common questions crash testing experts are asked are which testing method is "best". As one reads more in depth about the tests, it's clear that this is more or less impossible to answer.

Having a car seat certified by T and ECE R44 is supposedly the strictest standard but I'm sure there are people or experts who disagree. Seems like most experts agree on on disagreeing in some areas. I've also noticed that the deeper one digs the more factors pop up that are important and might be read and interpreted differently.

That's a short (yeah right) summary of the different tests. Now, if you managed to stay awake and read all this, I will buy a you a round of drinks

 

[snowbird25ca]

Thanks for sharing that. It's very interesting because it very much mirrors the comparison between FMVSS and CMVSS 213 standards. Different, not superior. We know that both countries seats protect children extremely well, and that's the ultimate determinant.

Perhaps somewhat ironically, this conversation shows that there is no way that one could definitively say - from an injury data perspective, that 5pt is less safe than a booster. Due to the factors of not knowing if comparable 5pt & boosters were being tested, rather only knowing that they passed. It's possible that a 5pt harness that exceeded standards, compared to a booster which just passed by the skin of it's teeth, would provide data showing the 5pt to give less risk of injury, while comparing an exceptional booster with a just passed standards 5pt could show reverse.

What we do know, is that an out of position child isn't protected by the seatbelt, and the harness remedies that problem. Even *if* there is a slightly increased risk of injury in a 5pt compared to a seatbelt, until a certain age, size, & maturity level is reached, that child is still absolutely going to be safest in a 5pt harness. Crash testing aside, young kids are less likely to stay in position, and the younger/smaller the child, the greater the risk of submarining and/or ejection in a booster seat. (Experience in North America anyways.)

Now, if every child could rear face until 5 or 6yrs old, going straight to a booster wouldn't really seem like such a shocking thing I'm sure, and likely wouldn't be debated the same way. :thumbsup:

(and nope, I didn't fall asleep reading it, but I've also read the online CMVSS 213 standards just for the education value. :thumbsup: )

 

[Adventuredad]

Very good conclusion. I think one reason why boosters are recommended ahead of 5 pr. harnessing over here in Sweden is that kids rf for quite a long time in their "regular seats". Going to a booster when you're 5 is very different from doing it at 3 years of age (or something like that).

It's a good point to bring up the seating position. I think this is often forgotten when discussing safety.

We are discussing the safety between the seats at times like it was a matter of pass or not pass. Both types of seats are good, I guess the answer we're looking for is by how much margin did the seats pass. Unless they do head to head tests we're unlikely to ever know and even if they do, results might not be as clear as imagined.

But it's an interesting discussion, I think it's good to widen the perspective a little bit and have knowledge what other people and countries are dong. Sometimes it's shockingly bad and sometimes it's great. Both things are to me very educational.

I'm impressed you read the CMVSS:thumbsup: I started looking at the ECE R 44 the other day and didn't have the energy to read it.... Maybe I need more wine before I go for it?

 

[scatterbunny]

My child hit the maximum rear-facing limits for any seat in the US at 2.5 years old. And, because rear-facing beyond 1 year old and 20 pounds was/is relatively unheard of in the US, I didn't know any better and she was forward-facing at about 13 months old.

I think if we had seats to accommodate kids to 5-6 years old rear-facing here, there'd be less "need" for extended harnessing (assuming the general public could wrap their brains around rear-facing beyond the minimums). Since we only have seats that rear-face to 30, 33 and 35 pounds here, many with relatively short seat shells (and rules about rear-facing height limits requiring the entire head to be contained within the seat shell), most kids are lucky to be able to rear-face to age 2-3, definitely much too young to safely use a booster seat properly (both from a maturity standpoint, and from a crash protection standpoint). We have to have those forward-facing harnessed options, then.

Crash testing and legal requirements are so interesting, and I love learning more, but real-world crash data is very important to consider, as well. If harnessing forward-facing was truly causing injury to children, wouldn't that be widely known, especially since it's been routine to forward-face in a five point/six point harness at (or even before) 1 year old and 20 pounds in the US, Canada and Australia for years?

I saw photographs of a 4yo girl who died in a properly used booster seat with lap+shoulderbelt a couple of weeks ago. You could see the bruising on her body, showing that the shoulderbelt hit her properly and restrained her, but the lap portion rode up too high on her belly and literally tore one of her internal organs in half. That type of submarining can happen with small children in booster seats, especially booster seats with poor designs that allow the lap portion to slip up during a crash.

There's no clear-cut answer, but I feel confident that younger children (under age 5-6) are less protected in a booster than in a harness, due to maturity issues and possible submarining/seatbelt syndrome injuries.

 

[Adventuredad]

Yeah, it's a shame about the somewhat limited rear facing options. I like extended rear facing because it's easy and I think that's a big part of the success. You basically get a good seat and keep it for many years. Cuts down on expenses and people don't have to think much about the seat they're using.

Maybe we're being a bit too picky at times about what we're discussing. Everyone here have very high standards, which is great for our children, but we should remember that both methods give good results when used correctly. Of course there are tragic deaths with 5 pt. harnessing as well as boosters but I think that's unfortunately unavoidable.

It's interesting and educational to see and hear the different points of views for me. Gives me a much greater perspective on car seat safety.