The Snell Memorial Foundation has some pretty strongly held ideas about what makes a good helmet. We look for protection from severe impacts and we want that protection over as much of the wearer's head as possible. We've set the most demanding Standards ever for auto racing helmets, motorcycle helmets, bicycle helmets and, now, for helmets used in skiing and snowboarding.
A brief technical comparison of the Snell requirements and the European Standard follows but the critical issues are these:
Even if it were available, no skier or snowboarder could possibly wear all the helmet he might need.
Instead, the Snell standards demand all the helmet a skier or snowboarder can reasonably be expected to wear.
The Snell Certification label in a helmet means head protection. We know because we look for it. We've tested samples of that helmet before it ever hit store shelves and then continually ever after.
Style, comfort and fit are up to the individual. You can tell us better than we can tell you. But protection is another matter. For all those people who lack the time and equipment for exhaustive helmet testing, the Snell Certification label is the surest sign that the helmet can perform its most important function, save your life when all your best judgment, skill and luck have failed to prevent a crash.
The following table shows a ranking of helmets from most to least protective. The weight of most auto racing helmets eliminates them from consideration even though these helmets are the most protective. However, skiers and snowboarders can and should wear more protection than we require for bicyclists. Unfortunately, most of the currently available skiing helmets are qualified only to the European CEN 1077 Standard.
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Snell SA-95 Auto Racing&Snell M-95 Motorcycle Helmets |
Snell RS-98 Winter Sports Helmets | Bicycle Helmets | CEN 1077 (European Standard) Ski Helmets |
| Snell RS-98 | CEN 1077
European Standard |
|
| Impact Testing | ||
| Flat Impact | 100 Joules
(2+ meter drop) |
(69 Joules - Size
M)
1.5 meter drop |
| Hemispherical Impact & Edge Impact | 80 Joules
(1.6+ meter drop) |
(no test) |
| Shell Penetration | 1 meter drop | 0.75 meter drop |
| Coverage - Test Lines | ||
| Front | Based on Auto Racing Requirements | .25 cm lower (1/10") |
| Sides | 2.25 cm lower (7/8") | |
| Rear | 1.7 cm higher (5/8") | |
The table shown above compares the Snell Memorial Foundation's RS-98 Standard for Protective Helmets for Recreational Skiing and Snowboarding with the widely used European Standard, CEN 1077.
Both Snell and CEN specify tests for impact protection. The essence of these tests is that a headform of a given mass is placed inside the helmet and the helmet/headform combination is dropped to impact against a given steel surface. For impacts with flat surfaces, CEN specifies a drop height of 1.5 meters but the headform mass and therefore the Joule figure depends upon the helmet size. The Joules in CEN 1077 vary from 61 Joules for the smallest adult size to 90 Joules for the very largest, the figure for an adult size medium is 69 Joules. The Snell test specifies the same headform mass and impact energy regardless of size. The drop height is just over 2 meters.
However, Snell also specifies impacts against hemispherical and edged surfaces. These surfaces concentrate the impact loading. Unless the helmet can spread that loading over its energy managing liner and over the wearer's head, the hemi or the edge can punch through the helmet's protection and deliver a potentially fatal blow to the wearer.
The shell penetration test attempts to drive a conical penetrator through the helmet to make contact with a headform. The driving force is essentially the momentum of a 3 kg mass dropped from a height of 1 meter for Snell RS-98 or 0.75 meters for CEN 1077. This is a traditional test that quickly identifies problems with certain shell technologies but it does not appear to be a critical issue.
Both Snell and CEN specify coverage. The table shows the relative placements of the test lines that limit where the various flat, hemispherical and edge surface impacts can be sited. Lower is generally better and, as can be seen, although the front test lines are virtually the same, the CEN lines are almost an inch lower than Snell's on the sides of the head while Snell is about 5/8" lower than CEN in the rear.
Snell has traditionally specified all the helmet an individual might reasonably be expected to wear and the test lines for the RS-98 helmet come from Snell's long experience in helmetry. The helmet shell must be cut to allow clearances for vision, for the wearer's ears, and for neck articulation. However, the shell's ability to manage impacts, particularly hemispherical impacts, is compromised near its edges. Good performance in hemispherical impacts at the Snell test line implies good flat anvil performance much lower. Snell has set the test line for the RS-98 to encourage the manufacture and use of the best possible winter sports helmet that current technology can provide.
