How useful are back protectors? (from the web)
(posts by license2ill from http://www.sport-touring.net/forums/showthread.php?t=71680)
Back protectors and lumbar protectors (EN 1621-2) are intended to provide protection against impacts against edges such as kerbing. However, while some 13% of motorcyclists sustain back injuries in crashes, the majority of these injuries are due to blows to the head or to bending and twisting of the back. A back protector will not prevent these types of injury. Less than 1% of injured riders suffer serious injuries from direct blows to the spinal area, however back protectors will provide protection from more minor injuries such as bruises and strains (EN 1621-2, p. 4).
So keep in mind, even the best and highest rated pieces are not made to limit bending or the typical injuries that cause paralysis or levels of force that cause major damage to the spine or rib cage. That's something that we might be able to change in the future, but it is still a worthy purchase, and purchasing the highest-performing, properly certified products will lead us to those ends.
The CE BACK PROTECTOR standard is labelled EN1621-2. The test is performed with a 5kg "kerbstone" dropped from one meter to create the test impact energy of 50 Joules. The standard contains two levels of force transmission performance, using the same impact energy. 18kN@50J passes LEVEL 1 compliance. 9kN@50J passes LEVEL 2 or "high performance" compliance.
"There has been criticism of the standard from medical experts who consider the transmitted force levels too severe; citing decades of automotive research which indicates 4 kN is the maximum force the brittle bones which form the human ribcage can withstand before they fracture. Four kiloNewtons is the requirement adopted in standards covering, for example, horse riders' body protectors and martial arts equipment. Attempts to reduce the transmitted force requirement to 4 kN and to correspondingly reduce the 50 Joule impact energy requirement were strongly resisted by industry, who claimed consumers would be confused by different impact energy requirements between EN1621-1 and EN1621-2.
In truth, it was in the industry's commercial interests to test both types of protector at 50J, since they could then extol the efficacy of back protectors which, when struck with the same impact energy as limb protectors, transmitted only 9 or 18 kN compared to 35 kN. The consumer would be unaware that subtle differences in the impactor and anvil were responsible, and still less aware that 9 kN was still more than double the safe limit supported by medical experts. Furthermore, during the late 1990s, some companies had used the wholly inappropriate EN 1621-1 to CE mark their back protectors. Commercial objectives were given priority over consumer safety.
Despite these concerns, EN1621-2 represents a starting point from wholly unsafe products should be rendered obsolete and unsellable. It will be important, however, for consumers to ensure back protectors are marked with the correct standard number, if they are not to mistakenly purchase an old stock."
The Horse Rider's torso protector standard is the Beta 2000 (same as CE EN 13158 for horse riders), which contains 3 levels based on impact energy, the level 3 test requires 4kN@45Joules, so at about 5 Joules less than the current CE motorcyclist protector standard. http://www.pva-ppe.org.uk/
The coverage area is also specified in the 1621-2 back protector standard. The European Standard EN 1621-2 states that it “specifies the minimum coverage to be provided by motorcyclists’ back protectors worn by riders in normal traffic situations. The standard contains the requirements for the performance of the protectors under impact and details of the test methods. Requirements for sizing, ergonomic requirements, and requirements for innocuousness, labelling and the provision of information are all included”. The following information is an overview of several of the specifications from this standard. The standard outlines several other specifications which must be met including ergonomic structure to ensure the comfort of the garment. It's basically a cross pattern for reference:
length: Minimum 510 mm Waist to Shoulder
A--Lower portion Length minimum from midline 72.5 %
B--Upper Portion Length Minimum from midline of shoulder 29.4%
C--Shoulder Width Minimum at midline 44%
D--Width at top/bottom, length at midline 29.4%
http://www.wpi.edu/Pubs/ETD/Availab...ed/mcarboni.pdf pg 82(74) Appendix A
The [Dainese Backspace] G2 performed pretty poorly in a French magazine comparison under the CE guideline tests with a failing 23.3 average.
Unfortunately it's too big to attach, but others in the article were the BMW with a best showing of 5.6kN, the Knox X1 at 6.6kN, the Dainese Wave at 11.4, the Alpinestars Tech at 14.3, the Knox Stowaway at a failing 21.1kN, and the old model Spidi Warrior at a failing 20.6. The aforementioned T-pro has been shown at 6.5kN in a German magazine test a couple years ago. Velocity Gear says their Dainese copycats have shown 4.5kN. Dainese has published numbers of all of their protectors, with almost all said to have passed the CE tests at an average of 16kN.
With all that in mind, 4kN will break ribs, so if the impact energy of 50J is appropriate, then every single piece available today comes-up short for the apparent design goals, and the trade laws have been compromised by the industry's inability to satisfy our real needs.
There is one piece that I've seen that advertises levels well within the CE requirements, its an air-bag piece, with a published 0.9kN pass. http://www.motoairbag.com/eng/prodotto.htm
While companies like Knox imply qualities above and beyond the capabilities, most companies don't provide an ounce of real info about their capabilities, and some are famous for espousing the ambiguous term of "protection" and "quality". Unfortunately, many people have made an inference with naive hopes and these companies take advantage. T-pro lists that info about their capabilities on their web page, and they are also one of the highest-performing protectors around. In general, certification is worthy of our vote and our purchasing decisions, but we should expect better from manufacturers of protective equipment in terms of information, and be more aware of current limitations.
My hope is that we can get past the throwing-the-towel-in stage for culpability of the manufacturers through the use of the standards. Standards didn't make helmets mandatory, but they made them better because it gives consumers more control over information and more power to make decisions based on real facts. Check out the info on other pieces of equipment like leathers, gloves, and boots. It only gets worse and more anecdotal.
If you read the info, you will find that injuries that typically cause damage to the spine are not direct hits, they are caused by blows to the shoulder and head, which perform a twisting under load on the spine. So back protectors, while they can and should be better at absorbing the direct blows than what is currently available, won't ever be capable of preventing scenarios that cause paralysis or death.
It's hard to put perspective on helmet design advancement, but luckily the voluntary Snell standard has added a lot to the development process. The one major difference is that the effectiveness over the last 20 years seems to have risen about 10%, so I guess that's the best measure of progress.