Draft 2010 STANDARD FOR PROTECTIVE HEADGEAR

For Use with Motorcycles and Other Motorized Vehicles

Special Note to Helmet Users

There are four reasons for you to be interested in this Standard:

1. The use of motorcycles and other motorized vehicles imposes risks of death or permanent impairment due to head injury.

2. The proper use of protective helmets can minimize the risk of death or permanent impairment.

3. The protective capacity of a helmet is difficult to estimate, particularly at the time of purchase or use. Protective capability is currently measured by destructive testing which is beyond the means most helmet wearers.

4. Snell certification backed by ongoing destructive testing of random samples taken from dealers and distributors identifies those helmet models providing and maintaining the highest levels of head protection.

Four of the most critical elements affecting a helmet's protective properties are:

1. Impact management - how well the helmet protects against collisions with large objects.

2. Helmet positional stability - whether the helmet will be in place, on the head, when it's needed.

3. Retention system strength - whether the chin straps are sufficiently strong to hold the helmet throughout a head impact.

4. Extent of Protection - the area of the head protected by the helmet.

This Standard describes simple tests for all four of these items. However, the tests for the second item, helmet stability, of necessity presume that the helmet is well matched to the wearer's head and that it has been carefully adjusted to obtain the best fit possible. Unless you take similar care in the selection and fitting of your own helmet, you may not obtain the level of protection that current headgear can provide.

The Foundation recommends the simple, straightforward procedure recommended to consumers by most helmet manufacturers:

Position the helmet on your head so that it sits low on your forehead; if you can't see the edge of the brim at the extreme upper range of your vision, the helmet is probably out of place. Adjust the retention system so that when in use, it will hold the helmet firmly in place. This positioning and adjusting should be repeated to obtain the very best result possible. The procedure initially may be time consuming. Take the time.

Try to remove the helmet without undoing the retention system closures. If the helmet comes off or shifts over your eyes, readjust and try again. If no adjustment seems to work, this helmet is not for you; try another.

This procedure is also the basis of the test for helmet stability described in this Standard. This test performs the same steps but uses standard head forms. However, you must still perform this procedure for yourself when buying a helmet and every time you wear a helmet. Only in this way will you be able to make all the proper adjustments to get the best fit possible. Furthermore, your test on your own head will be an improvement on ours; you will determine whether the helmet is appropriate for you personally.

There are several other important aspects of helmets to consider. Full face helmets provide a measure of protection from facial injuries. The external shell of these helmets includes a rigid "chin" guard that passes from left to right over the lower part of the face. The Foundation has devised special tests for the chin bars of full face helmets.

Some helmets come with a separate structure which bolts to the helmet and which is intended to cover the lower part of the face. These removable chin bars are often intended to deflect small stones and debris encountered in some motorcycle sports and may not be effective facial protection in falls and accidents. The Foundation does not test removable chin bars and considers any headgear equipped with them to be an open face helmet.

Helmets may also be equipped with a chin or full face guard that pivots or flips up for the rider’s convenience. These structures are considered as integral parts of the helmet and helmets equipped with them are considered full face helmets and are required to meet all of the test criteria for full face helmets. These flip up face guards must always be used in their locked position, or in accordance with the instructions from the manufacturer. Misuse of these fixtures may diminish the overall protective capabilities of the helmet.

If a full face helmet is equipped with a face shield, it may also provide a measure of eye protection. The Foundation tests the face shields of full face helmets for particle penetration resistance. Face shields provided with open face helmets generally do not provide the same levels of eye protection and, for that reason are not considered.

The shells of both open and full face helmets should also provide a measure of protection from penetration. The Foundation tests the shells of both full and open face helmets for penetration resistance.

Effective headgear must be removable. Paramedics and other emergency personnel must be able to quickly remove headgear from accident victims in order to check for vital signs and to perform emergency procedures. The Foundation has devised tests and criteria for helmet removability.

The Foundation tests helmets for visual field. The helmet must provide a minimum range of vision appropriate to its use as measured on standard head forms. Most Snell certified helmets will meet the requirements stated in this Standard and are considered appropriate for street use. However, the Foundation may also certify headgear with much more restricted visual fields for use only in carefully controlled competitive environments. Such headgear will include warning labels identifying them as appropriate only for certain activities.

Be absolutely certain that your helmet is appropriate for your intended uses. Furthermore, since the range of vision you obtain may vary considerably from our measurement, be absolutely certain that the helmet and face shield permit you adequate vision.

There are several important factors which the Foundation does not consider directly but which bear on the effectiveness of protective helmets. Be certain your helmet is wearable, that is, that it's comfortable and adequately ventilated when worn for prolonged periods. Few people will wear an uncomfortable helmet. A helmet that is not worn won't protect anyone. Also, while you’re trying the helmet on, take a good look in a mirror and ask some friends what they think. Most people will quit an ugly helmet much quicker than one that is merely uncomfortable.

Check for conspicuity. Bright colors and reflective patches will make you more visible to others and therefore less likely to be involved in a collision. All your riding gear and especially your helmet should be unmistakable, even to the most inattentive driver.

FOREWORD

In a motorcycle accident, the rider may suffer injury or death. Helmets on the market today offer varying degrees of protection, but the consumer has little basis for judging the relative effectiveness of a given model. This Standard presents rational methods for identifying those helmet models which definitely meet specified standards for impact (crash) protection and retention system strength and, afterwards, identifying those which definitely have ceased to meet those standards.

The Snell Foundation urges that protective helmets be required for all individuals participating in supervised racing events and encourages the general public to wear helmets which meet appropriate performance standards[1].

This 2010 Standard establishes performance characteristics suitable for motorcycling and for use with other open motorized vehicles in which the driver and passengers may not be enclosed such as boats, motorized carts, all-terrain vehicles and snowmobiles. This Standard does not establish construction and material specifications. The Foundation does not recommend specific materials or designs. Manufacturers voluntarily submit helmets to be tested to this Standard and if the submitted helmets pass, a certification is issued.

The Foundation will make available the identity of those products which have been Snell certified but will not attempt to rank those products according to performance nor to any other criteria. Neither does the Foundation distinguish between the needs of participants in competitive events and those of the general public.

All of the requirements described herein, including both initial certification and random sample testing, are an integral part of this Standard. No helmet can satisfy the Standard unless it is subject to both certification and random sample testing by the Foundation.

Snell certification for protective headgear requires a specific contractual agreement between the primary headgear manufacturer and the Foundation. Certification procedures may be obtained upon application to the Foundation.

SNELL MEMORIAL FOUNDATION is a registered certification mark and M2010 is a certification mark of the Snell Memorial Foundation.

INTRODUCTION

This Standard addresses the problem of protecting the head from direct impact with surfaces or objects that might be encountered in a motorcycling accident. The Standard prescribes direct measures of several factors bearing on a helmet's ability to protect the head as well as its general serviceability as motorcyclist headgear. Thus, this Standard is directed towards the kinds of performance bearing on head protection that may not readily be discernable by even knowledgeable consumers at the time of purchase.

Some of these performance requirements have been expressed in terms of limitations on the various components and features of the single general helmet configuration currently available. These expressions have been used only for the sake of clarity and should not be misinterpreted as requiring specific configurations or materials. As newer helmet technologies appear, these limitations will be re-examined and, perhaps, restated.

A motorcycle helmet consists generally of a rigid head covering and a retention system composed of flexible straps and hardware. The rigid covering consists of a stiff outer shell and a crushable liner. The stiff outer shell protects by its capacity to spread a concentrated load at its outer surface over a larger area of the liner and the wearer's head. The crushable liner protects the head from direct impact by its capacity to manage impact energy.

The retention system holds the headgear in position throughout normal usage and especially during falls and accidents. This Standard applies two different tests to the retention system. The first of these tests for stability by fitting the headgear to a standard head form and then attempting to displace it by applying tangential shock loadings. The second tests retention system strength by applying a shock load to the system components through a simulated chin.

The quality of the fit and the care taken with the adjustments are absolutely critical elements in these tests. The manufacturer must provide suitable guidance so that the wearer will be able to select and adjust headgear to obtain the necessary quality of fit and positional stability.

The capacity for impact protection is determined by direct measurement of the shock delivered through the helmet to a head form when the helmeted head form is dropped in a specified manner onto any of three unyielding anvils.

Most motorcycle helmets are intended to accommodate a range of head sizes and shapes. Various thicknesses of resilient padding are sometimes placed within otherwise identical helmets during production or during fitting to configure the helmet to several different ranges of head size. This resilient padding does not significantly affect the way the helmet absorbs and attenuates impact and is not directly addressed in this Standard.

The helmet must also resist penetration by sharp edged and pointed projections and projectiles. This capacity is tested by placing the helmet on a head form and dropping a metal cone of specified mass and geometry onto the shell. The tip of this cone must not penetrate to the head form.

Similarly, the helmets must resist chemical attack by bodily fluids as well as solvents and chemicals associated with motorsports. This capacity may be tested by applying a solvent mix before further conditioning and testing.

Full face helmets provide a measure of facial protection in addition to the impact protection generally sought. The principle feature of a full face helmet is a chin bar that extends forward to cover the jaw area converting the facial opening into a visual port. Frequently, a face shield is also provided so that the wearer's face is completely covered.

In order to be considered a full face helmet, the chin bar must be an integral part of the helmet structure. This interpretation specifically includes configurations in which the chin bar pivots about a hinge up and away from the face but excludes simple “bolt-on” chin coverings. The Standard then tests the rigidity of the chin bar by dropping a weight onto it at a specified velocity so as to attempt to force the chin bar toward the interior of the helmet. The chin bar must not deflect more than a specified amount.

If a face shield is provided with a full face helmet, then this face shield must resist penetration by small particles. A sharp lead pellet of a specified weight is directed into the face shield at a specified velocity. The pellet must not penetrate into the helmet interior.

This Standard also includes a test intended to determine whether the headgear may be removed from an unconscious accident victim quickly, easily and reliably in spite of any damage the headgear might reasonably be expected to sustain. Traditional helmet architectures have satisfied this requirement so readily that many Standards including previous Snell Foundation Standards have not mentioned it. Even so, it is unthinkable that a headgear might protect its wearer in an accident only to thwart attempts at rescue afterward.

Inadequate ventilation may render a helmet unwearable in hot climates, especially if the helmet is full faced. But this Standard makes no direct demands on either the quantity or quality of air flow to the wearer.

Other general features of motorcycle helmets may include eyeshades and accommodations for goggles, and visibility enhancements such as bright colors and reflective surfaces. These features all deal with matters of safety and comfort that are not directly addressed in this Standard but which merit the consideration of wearers as well as manufacturers.

Although helmet use has been shown to reduce the risk of head injuries significantly, there are limits to a helmet's protective capability. No helmet can protect the wearer against all foreseeable accidents. Therefore injury may occur in accidents which exceed the protective capability of any helmet including even those helmets meeting the requirements of this Standard.

A helmet's protective capability may be exhausted protecting the wearer in an accident. Helmets are constructed so that the energy of a blow is managed by the helmet, causing its partial destruction. The damage may not be readily apparent and the Foundation strongly recommends that a helmet involved in an accident be returned to the manufacturer for complete inspection. If it is not possible to do so, the helmet should always be destroyed and replaced.

Finally, the protective capability may diminish over time. Some helmets are made of materials which deteriorate with age and therefore have a limited life span. At the present time, the Foundation recommends that motorcycle helmets be replaced after five (5) years, or less if the manufacturer so recommends.

CONSTRUCTION

A. General

The assembled helmet shall have smooth external and internal surfaces. Any feature projecting more than 7 mm beyond the outer surface must readily break away; all other projections on the outer surface shall be smoothly faired and offer minimal frictional resistance to tangential impact forces. Rivets and similar projections into the helmet interior must offer no laceration or puncture hazard. Restraint clips may be used at the rear or on the side of the helmet. The helmet shall provide as nearly uniform impact protection over the entire protected area as is possible.

If the absence of any detachable component of the helmet does not prevent its being worn, then this absence must not compromise either the retention system or the impact protection. If any part of the helmet detaches during testing, it must offer no laceration or puncture hazard nor reduce the coverage of the head.

If the manufacturer provides add-ons such as visors, face shields and neck curtains with the helmet, these add-ons must not lessen the protective capability of the basic helmet nor reduce the visual field below standard requirements nor create a direct hazard for the wearer.

B. Shell

If rivets are used, the heads shall not have sharp edges and shall not project more than 2 mm from the outer surface of the helmet.

C. Materials

Ideally, materials used in the manufacture of the helmet should be of durable quality and not be harmed by exposure to sun, rain, dust, vibration, sweat or products applied to the skin or hair. Similarly, the materials should not degrade due to temperature extremes likely to be encountered in routine storage or transportation.

Materials which are known to cause skin irritation or are conducive to disease shall not be used for the parts which contact the skin. Materials that support the growth of fungi or algae shall not be used. Fabric lining or padding materials, if used, may be detachable for the purpose of washing so long as their absence does not degrade the protective capabilities of the helmet.

D. Finish

All edges of the helmet shall be smoothed and rounded with no metallic parts or other rigid projections on the inside of the shell that might injure the wearer's head in the event of impact.

E. Retention System

The retention system shall be designed so as to discourage misuse. That is, of all the ways in which the retention system might be used, the design use shall be the simplest and quickest to implement. Helmets shall not be fitted with "non-essential" features which, if misused, can degrade the performance. Quick release buckles, if used, shall not be able to be released inadvertently.

Fabric chinstraps, if used, shall not be secured to the shell by a bolt, pin or rivet passing through the fabric itself. Although other alternatives may be proposed, the preferred method of attachment is that the strap be looped through and sewn about a metal hanger which can then be secured to the shell by bolt, rivet or other appropriate means.

F. Peripheral Vision

The helmet shall provide peripheral visual clearance as measured using a reference head form appropriate to the size of the helmet. This peripheral vision includes a horizontal clearance of at least 210º, an upward clearance of at least 7º and a downward clearance of at least 30º. However, this downward clearance makes specific allowance for breath deflectors. These clearances are described in terms of planes fixed in the reference head forms.

Some competitive applications may require helmets with more restricted visual fields. When justified, special addenda to this Standard will define reduced visual fields, the procedures for determining whether a helmet satisfies the requirement and the additional labeling requirements warning that the headgear may be appropriate only for certain uses.

G. Sizing

The requirements of this standard are such that most helmets will perform optimally only when tested within a range of head circumferences. Outside this range, helmets may still provide a measure of protection but they may not meet requirements for certification. The manufacturer must specify this entire range when helmets are submitted for certification. Later, when helmets are distributed for sale, every helmet shall include a permanent label indicating the range of head circumferences for which it is intended.

QUALIFICATIONS FOR CERTIFICATION

For qualification testing, helmets shall be in the same condition as those offered for sale. No helmet or component which has been subjected to any tests described in this Standard shall be offered for sale after testing. A total of five (5) complete helmets must be submitted by the manufacturer for a certification test program for each distinct structural configuration of the models offered for sale. Four of these samples will be destroyed in testing, the fifth shall be retained for comparison and reference.

MODIFICATIONS

Cosmetic changes to certified headgear are permissible. Such changes are generally limited to marking or trimming the headgear with manufacturer approved paint or tape. Otherwise, modifications to certified headgear effectively create new configurations which shall not have the confidence and certification of the Foundation until properly evaluated. Manufacturers must not place the Foundation's certification label in any modified headgear without the Foundation’s written authorization.

The Foundation recommends that helmet owners not modify or contract someone else to modify their helmets. Any structural modification may adversely affect a helmet's protective capability. The Foundation’s certification and, quite likely, all manufacturer warranties apply to the headgear only in its as manufactured condition.

RANDOM SAMPLE TESTING

In addition to the certification testing, the Foundation will routinely obtain and test samples of previously certified models. These samples will be selected from among those stocks intended for retail sale to consumers. In this manner, the Foundation will attempt to ensure that the helmets made available to the public continue to meet the performance requirements of this Standard.

In cases where helmets are provided directly to users and do not pass through a normal sales distribution system, the Foundation will set up alternative procedures to monitor certified products. Specifically, if helmets are provided directly to teams or individuals for use in events, the Foundation must have access to the helmets for spot checking and non-destructive evaluation.

LABELING AND MARKING

Each helmet shall have durable, visible and legible labeling identifying the manufacturer, the month and year of manufacture, the model and the size. Labeling shall be uncoded and either in English or a language common to the area where the helmets are to be distributed. The headgear shall also be labeled to the following effect:

1. No helmet can protect the wearer against all foreseeable impacts. However, for maximum protection, the helmet must be of good fit and the retention system must be securely fastened to retain the helmet. The helmet, when fitted and fastened, shall not be removed easily.

2. This helmet is so constructed that the energy of an impact may be absorbed through its partial destruction, though damage may not be visible. If it suffers an impact, it must either be returned to the manufacturer for inspection or be destroyed and replaced.

3. Intended for head circumferences from XX cm through YY cm.

If any of the helmet components are sensitive to common solvents, adhesives, paints or cleansers; the helmet must also bear labels to the following effect:

This helmet can be seriously damaged by some common substances without visible damage. Apply only the following: (Recommended cleaning agents, paints, adhesives and the like) as appropriate.

If the helmet model was certified according to a special addendum to this standard, each helmet shall also include the warning labels required by that addendum.

Each helmet shall also include one of the Foundation's serialized certification labels. The Snell certification label shall be placed either inside or on the outside of the helmet, as appropriate, in such a way that it cannot be removed intact.

The registered trademark (certification label) of the Snell Memorial Foundation may be used by the manufacturer only under license from the Snell Memorial Foundation. The specifics of licensure may be obtained from the Foundation.

MARKING AND LABELING OF CRITICAL COMPONENTS

If a helmet component may reasonably be replaced with an inappropriate substitute that might degrade wearer safety and performance in any of the tests called out in this standard, the manufacturer must mark those components so that users may avoid the purchase and use of inappropriate replacement parts. In particular, face shields on full face helmets must be marked to identify the manufacturer and the month and year of manufacture.

HEAD FORMS

This standard invokes six standard head forms for helmet inspection, marking and testing. The geometry of these head forms is according to the definitions for the ‘A’, ‘C’, ‘E’, ‘J’, ‘M’, and ‘O’ head forms described in International Standards Organization (ISO) Draft Standard ISO DIS 6220-1983. The impact mass specifications for the impact test phase are comparable to those in ECE 22-05 for these same head form designations.

ISO DIS 6220-1983 includes descriptions for half head forms suitable for guided fall impact testing or for full head forms such as those used in the positional stability tests. Figures 1 and 2 depict the general shapes of the half head form configuration. The following table lists useful dimensions from the two references given above.

Head Form	Circumference	Mass (± 100 g)	Crown to Basic Plane	Basic to Reference Plane
A	50 cm	3.100 kg ± 100 g	113.5 mm	24.0 mm
C	52 cm	3.600 kg ± 100 g	118.0 mm	25.0 mm
E	54 cm	4.100 kg ± 100 g	122.0 mm	26.0 mm
J	57 cm	4.700 kg ± 100 g	130.0 mm	27.5 mm
M	60 cm	5.600 kg ± 100 g	136.0 mm	29.0 mm
O	62 mm	6.100 kg ± 100 g	140.0 mm	30.0 mm

EXTENT OF PROTECTION

The extent of protection corresponds to that region of the head for which protection is sought.

There are a number of planes fixed in the geometry of these head forms as shown in Figure 1. This description of the extent of protection uses the ISO definitions of the basic plane, the longitudinal plane, the transverse plane and the reference plane. Other planes have also been defined strictly for convenience and clarity.

The basic plane corresponds to the anatomical plane (Frankfort plane) that includes the auditory meatuses and the inferior orbital rims. The reference plane is above and parallel to the basic plane. The longitudinal or midsagittal plane is perpendicular to the basic plane and is the plane of symmetry dividing the right half of the head form from the left. The transverse or coronal plane is perpendicular to both the longitudinal and basic planes. It corresponds to the anatomical plane that contains the two auditory meatuses and divides the front from the rear portions of the head.

These planes are all well known entities. Several other planes, however, have proven useful. The S₀ plane is parallel to the basic plane and lies above it at a distance determined by the size of the head form. The S₃ plane is parallel to the S₀ plane and the basic plane and lies between them. The S₄ plane is also parallel to these planes and lies below the basic plane.

The rear plane divides the rear third of the head from the front two thirds. It is parallel to the transverse plane and lies at a given distance behind the point where the reference plane and longitudinal planes intersect with the front surface of the head form. The distance from this point, hereafter called the reference point, is determined by the size of the head form. The fore plane is also parallel to the transverse plane. It lies behind the reference point at a distance determined by the size of the head form.

The extent of protection provided by the helmet must include the entire region above the S₀ plane and forward of the fore plane, the entire region above the S₃ plane and between the fore and rear planes and the entire region above the S₄ plane and behind the rear plane. Figure 2 and the associated table lay out these additional defined features and show the extent of protection and the test line.