Snell Memorial Foundation has one of the most advanced and busiest helmet testing facilities in the world. Snell's California helmet testing laboratory is the one of the few in the United States accredited to ISO 17025 by the American Association for Laboratory Accreditation (A2LA).

How Helmets are Tested in Snell Labs
Before a helmet can be Snell-certified, it is tested in Snell's state-of-the-art test facility. Snell technicians conduct a variety of tests to determine the helmet's performance and ability to stay on the head in different environmental conditions -- wet, heat, cold. Depending on the application and the standard, each helmet must pass all or some of the following tests:

Impact Test
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 (Flat, Hemisphere, Kurbstone, Roll bar, edge or a horseshoe type) which simulate different impact surfaces. (See below for the picture). The head forms are instrumented with an accelerometer to measure peak G force or acceleration which is measured in "G"ravitational units. The impact energy (drop height and mass), or how hard the helmets are impacted is unique to each standard. However, if in any valid test the peak acceleration imparted to the head form exceeds 300 G's, the helmet is rejected.

Positional Stability (Roll-Off) Test
A head form is mounted on a stand so that it points face downward at an angle of 135 degrees. The helmet is placed on the head form and the straps and buckles adjusted to obtain a "best fit". A wire rope is hooked to the rear edge of the helmet and brought forward so that its free end runs across the helmet and downward towards the floor. The free end of the rope has a mechanical stop with a 4 kg weight resting on the stop. The weight is raised to a prescribed height and dropped onto the stop. The resulting shock places a rotational load on the helmet. The helmet may be shifted, but must not roll off the head form. Next the head form is rotated 180 degrees, the helmet adjusted, and tested with the wire rope hooked to the front edge of the helmet and the test is repeated. As in the first case, the helmet may be shifted but must not roll off the head form.

Dynamic Retention Test
The helmet is placed on a head form and the chin strap fastened under a device approximating the contour of the jaw. 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 maximum instantaneous deflection (stretch) of the retention system exceeds 30 mm. Drop heights for the 38 kg mass are different for each standard, however the mechanism and failure criteria are similar for other types of headgear.

Chin Bar Test
The chin bar test applies to full face motorcycle, special application racing and kart racing helmets. The helmet is affixed to a rigid base with the chin bar facing upward. A 5 kg weight is dropped through a guided fall to strike the central portion of the chin bar. Maximum downward deflection of the chin bar must not exceed the stated distance.

Shell Penetration Test
The shell penetration test applies to motorcycle, special application racing, kart racing, skiing and equestrian helmets. The helmet is affixed to a rigid base. A 3 kg sharply pointed striker is dropped in a guided fall onto the helmet from a prescribed height. The test striker must not penetrate the helmet or even achieve momentary contact with the head form.

Faceshield 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. Pellet speed will be approximately 500 kph. For the both types of shield the pellet must not penetrate, and for the racing helmet any resulting "bump" on the inside of the shield must not exceed 2.5 mm.

Flame Resistance Test
The flame resistance test applies to special application racing helmets only. The test is conducted using a propane flame of approximately 790 degrees centigrade. The flame 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. During the whole process the temperature of the interior lining of the helmet must not exceed 70 degrees centigrade.

Three Basic Types of Testing Programs

Certification Test
Official pre-market evaluation for admission to the Foundation's Certification programs. The manufacturer submits a number of helmet samples, depending on the helmet type and Snell standard to the Foundation for testing. Snell technicians at Snell laboratories subject these samples to the most rigorous testing permitted by the Standard. Any failure on any sample is a cause for rejection.

Random Sample Test (RST)
Required testing and evaluation for all certified helmets. The Foundation acquires helmet test samples directly from stocks of helmets that are meant for sale or distribution to the general public, or specific groups of users, usually from retail or distribution sources. The number of samples we will buy is based on the number of Snell certified helmets the manufacturer has produced. Snell technicians in Snell laboratories inspect and test each sample to check that the helmets used by the public continue to meet the Foundation's high standards. If it is found that these RST helmets fail to meet the testing criteria, three more samples are obtained and tested to confirm the findings of the first tests. If any of these three follow up tests result in failure, the Foundation first demands that the manufacturer discontinue production of these helmets as Snell certified products. The Foundation will then continue to investigate the matter and determine a suitable course of action. These actions can range from requiring the manufacturer fix the problem and recertify the helmet, to a complete decertification of the manufacturer's certified product line. In some cases Snell will require that all Snell decals distributed to that manufacturer be returned.. This basically amounts to a full scale recall. Gratefully, this rarely occurs because of the procedures taken during the certification and Random Sample Testing.


Prototype Test
Unofficial evaluation. Manufacturers may submit one or more helmet samples and request specific tests and test configurations. The Foundation will not consider prototype test data in evaluation for Certification. However, manufacturers may find prototype testing useful in product development.