Snell Helmet Safety Standards - Is It As Good As They Say?

December 16, 2020 6 min read

With so many helmet certification choices, riders can find themselves under-informed in terms of safety aspects. The Snell Foundation, Inc., a nonprofit organization, has put together a report centered around the terms of vehicular headgear safety. This report is solely for scientific and educational purposes, with an interest in promoting safety and retention of life to users. Snell extensively tests according to various categories and certificates that have passed on all accounts.

Because motorcycle-use imposes a higher risk of injury, it is important to draw some testing conclusions about a helmet’s efficacy and measure the level to which one would protect the wearer, then subsequently inform the public and manufacturers of the findings. The testing measures of a helmet’s protective properties are focused on four primary areas:


  • Impact Management: the degree to which a helmet protects the wearer against collisions with large objects.
  • Positional Stability: will the helmet remain on the wearer’s head when it is most pertinent.
  • Strength Of Retention System: will the chin straps be strong enough to hold the helmet in case of impact.
  • Protection Extent: how much of the head is protected by the helmet.


Important Considerations

There are several important aspects of helmet testing that are worthy of note before further elaboration. Helmet testing goes a long way, but it does not preclude the responsibility of the wearer to make sure the helmet fits them appropriately. The test on one’s own head will assist in determining whether the helmet is appropriate for the wearer’s head.

Full-face helmets add additional protection by guarding the face and eyes. These are normally equipped with a chin guard - an immovable part of the helmet that must be hinged in such a way to allow the helmet’s opening, access, or removal. Some have a facemask that lifts upward and away from the face called modular helmets. These helmets are bound by the same safety requirements as their full faced counterparts. While the Snell Foundation does not test bolt-on chin bars (considering these to be comparable to open face helmets), they do test full-face helmets for penetration by particles through the facemask. Face shields are not considered in testing as they do not provide the same level of protection.

In the case of an accident and the involvement of paramedics, the helmet must be easily removed. Snell recognizes this requirement and also tests both full and open face helmets for helmet removability to assure that if medics need to remove the helmet to perform emergency procedures, they would be able to do so with expediency.

Additionally, helmets must meet the minimal standard for range of vision. Snell certified helmets are acceptable for street use if they meet such a threshold, though the Standard will also qualify certain helmets with lower visual scope for use in competitive, but highly controlled environments. These will include warning labels deeming them appropriate for certain activities, as it is important to use helmets only for their intended uses.

It is important to note that while helmets do significantly decrease the chances of injury or death in an auto accident, no helmet can guarantee protection against all possible accidents. Helmets are designed to absorb impacts by distributing its energy, however, this causes the helmet to endure damage. Any helmet that is involved in an accident, no matter how minor, should be closely inspected by the manufacturer. If it is deemed sufficiently damaged, it should be destroyed and discarded.

On the same note, Snell recommends that helmets be replaced at least every 5 years, or by the recommended standards of the manufacturer if it should be done more frequently. This is because, over time, most helmets’ protective abilities diminish.


Helmet Construction Standards

Helmets have baseline standards for their construction, including the following:

  • General
    • Surfaces must be smooth on the inside and outside.
    • Any part that extends more than 7mm outside of the helmet's surface must be able to break away easily to avoid any chance of punctures or cuts.
    • The protection area should be as uniform as possible.
    • Restraint clips can be used at the rear or side of the helmet.
    • Any part that detaches must be present on the helmet, or if it is absent, the fact that it isn’t present must not impact protection or the ability of the helmet to stay on the wearer’s head.
    • Any face shields or visors included should never reduce the visual field of the wearer below the standard requirements.


  • Shell
    • Any rivets used must not extend more than 2mm from the surface.
    • Any extending parts must not have sharp edges.


  • Materials
    • Materials should not degrade when exposed to the natural elements (sun, dust, rain), vibration, or other materials it comes in contact with (sweat, products on skin or hair).
    • Materials should not degrade when stored in extreme temperatures (as could occur in either storage or during transportation).
    • Materials with well-known skin allergens will not be used in the construction of a helmet.
    • Removable linings taken out for the sake of cleaning are acceptable, as long as taking them out does not degrade the helmet’s ability to serve as adequate protection.
    • Any materials that can grow algae or fungus when damp from sweat should not be used.


  • Finish
    • All edges should be smooth.
    • There should be no parts protruding on the inside of a helmet.


  • Retention Systems
    • The design to retain the helmet on the wearer’s head must be simple and easy to achieve, discouraging misuse.
    • Helmets should not contain non-essential features.
    • If the helmet uses quick-release buckles, they must be certain to not release on their own.
    • The preferred method of helmet retention should be a strap that is looped and sewn around a metal hanger which can then be held in place by reliable, secure means, such as rivets or a bolt.


  • Peripheral Vision
    • The helmet, as long as it is appropriate for a wearer's head, must provide sufficient visual clearance of at least 210 degrees of horizontal clearance, 7 degrees of upward clearance, and 30 degrees of downward clearance.
    • Reduced visual clearance is acceptable only for helmets for very specific purposes used in controlled environments. These will require that the helmet have a label stating its intent of use for only particular purposes.


  • Sizing
    • Helmets should perform at an optimum level when on the appropriately sized head of the wearer suited to the helmet.
    • The manufacturer needs to specify the range of helmet appropriate head sizes.
    • Each helmet must be distributed with a permanent label assuring that wearers know what head circumference it is intended for.


Performance Testing

During testing, the helmet is subjected to a series of dynamic tests. These tests range from verifying the strength of helmet retention, stability, shell penetration, removability, and impact management. The testing conditions are done at lab temperatures specifically controlled to be similar to those in which the helmet might be used. 

Before the testing begins, helmets are exposed to a variety of common solvents applicable in motorsports. This is done to assure that these chemicals do not degrade the helmet or its components.

Certification testing has four required testing samples to assure appropriate head form:


  • One sample is kept in a lab-controlled environment to allow ambient temperatures and humidity to come to an equilibrium. It is then subjected to positional stability tests, followed by impact testing.
  • The second through fourth is subjected to tests after being conditioned in either cold, wet, or hot temperatures before retention and impact testing.


Only those helmets tested in the controlled ambient lab temperature will be tested for positional stability and will be tested no more than once as the impact testing will degrade the helmet’s effectiveness. 

Impact testing can be performed on any of the samples but should not be done to helmets which have been previously subjected to shell penetration testing. The impact testing involves a series of tests during which a helmet endures guided falls onto test anvils. The site of the impact will be assessed to indicate whether the helmet meets the impact testing requirements. If parts of the helmet interfere with the testing, these may be cut away as the testing is more important than retaining the helmet’s design.

For shell penetration testing, a helmet is placed on a stable head form, then struck with a metal spike at varying weights at varying velocities. The expectation of all those tested is for the helmet to deny all attempts of the spike penetrating the head form. Similarly, testing is done on a face shield using a pellet gun to fire high-velocity pellets to simulate road debris.



If the helmet passes all of the tests and meets certification, at least one helmet sample will be taken apart and inspected. In order to not be rejected, the lab staff must not find any features compromised internally. The helmets can be disassembled at any time based on the discretion of the technician.


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[1] U.S. Department of Transportation, National Highway Traffic Safety Administration, National Center for Statistics and Analysis, Traffic Safety Facts,Crash, available at

[2] Snell Foundation, Incorporated, 2020 Standard for Protective Headgear, (2019). Retrieved from