What are Snell Foundation Helmet Safety Standards for Action Sports Helmets?The Snell Memorial Foundation is a nonprofit organization dedicated to research, education, testing, and development of helmet safety standards. Founded in 1957, the Snell Foundation began issuing auto racing helmet standards, followed by motorcycle, bicycle, equestrian, ski, and other helmet standards. Snell's standards are the most demanding of any helmet certification. Helmets must first pass Snell certification testing by Snell technicians in Snell labs to qualify for Snell programs. Then samples of these helmets regularly acquired directly from retailers and distributors must continue to pass test requirements in order to retain Snell certification. Testing helmets acquired on the consumer market forces manufacturers to be careful about quality control. The relevant Snell Foundation standards for action sport helmets include:
- Snell B-90/95, Snell N-94: Bicycle helmets
- Snell RS-98 or S-98: Ski helmets
The Snell Foundation Testing Process in BriefSnell technicians conduct a variety of tests to determine the helmet's performance and ability to stay on the head in different environmental conditions, including ambient, wet, heat, and cold. Depending on the application and the standard, each helmet must pass all or some of the following tests. Snell bicycle helmet standards look at four aspects of a helmet:
- Impact management - how well the helmet protects against collisions with large objects.
- Positional stability - whether the helmet will remain in place
- Retention system strength - whether the chins straps are strong enough to keep the helmet in place
- Extent of protection--how much of the head is covered by the helmet
This test involves a series of controlled impacts where a helmet is positioned on a metal head form and then dropped in a guided fall onto various steel test anvils to simulate different impact surfaces. If the peak acceleration imparted to the head form exceeds certain threshold value, typically around 300 G's ("G" gravitational units), depending on standard and test type, the helmet is rejected.
- Positional Stability (Roll-Off) Test: In this test, the head form is mounted on a stand and the helmet straps and buckles adjusted to obtain a "best fit." The technician places a weighted rope onto the helmet, which is then dropped, placing a rotational load on the helmet. The helmet may shift but must not roll off the head form. This test is done from two different angles.
- Dynamic Retention Test: The Dynamic Retention Test tests the strength of the helmet chinstrap and buckle. The jaw piece is loaded with a 23 kg weight for approximately one minute. The retention system is tested by simultaneously removing the 23 kg weight and applying a 38 kg mass in an abrupt guided fall. The retention system fails if it cannot support the mechanical loads or if the retention system stretches more than 30 mm. The drop heights differ depending on the helmet standard being measured.
- Chin Bar Test: The chin bar test measures the strength of the chin bar portion of full face motorcycle, special application racing, and kart racing helmets. The helmet is fixed to a rigid base with the chin bar facing upward. A 5 kg weight is dropped on the central portion of the chin bar.
- Shell Penetration Test: The shell penetration test applies to motorcycle, special application racing, kart racing, skiing, and equestrian helmets. A 3 kg sharply pointed striker is dropped in a guided fall onto the helmet, which is fixed to a rigid base. The test striker must not penetrate the helmet or even achieve momentary contact with the head form.
- Face shield Penetration Test: The face shield penetration test applies to full face motorcycle, special application racing, and kart racing helmets. The face shield is affixed to the helmet and shot along the center line in three separate places with an air rifle using a sharp soft lead pellet.
- Flame Resistance Stand: The flame resistance test applies to special application racing helmets only. The test is conducted using a propane flame of approximately 790 degrees centigrade that is applied to the shell, trim, chin strap and face shield for a specified number of seconds, and any resulting fire must self extinguish within a specified time after flame removal.
What If My Helmet Doesn't Meet Snell Standards?It is common to find motorcycle helmets that bear the Snell safety standard. Bicycle helmets, especially those sold in the United States, are less likely to have undergone Snell Foundation testing because:
- The Snell testing is a longer, more stringent process and includes testing of helmets purchased on the consumer market
- The Snell testing procedure for bicycle helmets is similar to the CPSC bicycle helmet test process. The US government requires bicycle helmets to meet CPSC standards. It's more expedient for manufacturers to test to the required standard.