DRAFT Snell / FIA CM2007 Child Motorsports Helmet Standard for Protective Headgear

Ver. 03-21-07

 Table of Contents

                                                                                                                                                                                                                                                                      In pdf   2.5 mb

FOREWORD   E.  Peripheral Vision
QUALIFICATIONS FOR CERTIFICATION     Figure 4.   Lateral Field of Vision
MODIFICATIONS     Figure 4B. Lateral Field of Vision (Restricted)
RANDOM SAMPLE TESTING     Figure 5.   Downward Visual Field
CONSTRUCTION     Figure 5B. Downward Visual Field (Restricted)
  A. General     Figure 6.   Breath Deflector Allowance
B.  Shell   F.  Performance Testing
  C.  Materials     F1.  Conditioning
  D.  Finish     F2.  Positional Stability (Roll Off)
  E.  Retention System     F3.  Dynamic Retention System
  F.  Peripheral Vision     F4.  Impact Management Testing
  G.  Weight       1.  Equipment
LABELING AND MARKING       2.  Test Definitions
MARKING AND LABELING OF CRITICAL COMPONENTS       3.  Impact Definitions
HEAD FORMS       4.  Impact Test Interpretations
  Figure 1 - ISO Head Form  ISO DIS 6220-1983     F5.  Chin Bar Testing
EXTENT OF PROTECTION       F5a.  Chin Bar Rigidity
  Figure 2  Extent of Protection       F5b.  Chin Bar Impact
TESTING     F6.  Shell Penetration
  A.  Helmet Positioning     F7.  Face Shield Penetration
  B.  Inspection     F8.  Removeability
  C.  Marking     F9.  Post Test Inspection
  D.  Shell Edge Lower Limit    
    Figure 3.    Upward Visual Clearance    
    Figure 3b.  Upward Visual Clearance (Restricted)    

 

 

 

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DRAFT STANDARD FOR PROTECTIVE HEADGEAR  03-21-07

For Use in Children’s Motor Sports Activities

FOREWORD

          In motor sports accident, participants 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 these standards.

          The Snell Memorial Foundation and the Federation Internationale de l’Automobile (FIA) urge that protective helmets be required for all individuals participating in supervised racing events and encourage the general public to wear helmets which meet appropriate performance standards1.  To this end, the Snell Memorial Foundation and the FIA jointly announce this Standard for children’s motor sports helmets and will share the responsibility for a program of certification to this Standard.

          This Standard does not establish construction and material specifications.  

          This Standard establishes performance characteristics suitable for children’s use in motor sports involving motorcycles, power boats, karting, all-terrain vehicles and snowmobiles.  Manufacturers voluntarily submit helmets to be tested to this Standard and if the submitted helmets pass, a certification is issued.

          The Snell Memorial Foundation and the FIA will make available the identity of those products which have been certified.  These products are for both competition and general use for the age categories and activities specified.

          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.

          Snell/FIA 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 and FIA are registered certification marks.   CMH (Children’s Motor Sports Helmet) is a certification mark jointly held by the Snell Memorial Foundation and the FIA.

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.

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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 Snell/FIA until properly evaluated.  Manufacturers must not place the Snell/FIA certification label in any modified headgear without express written authorization.

          The Snell Memorial Foundation and FIA strongly recommend 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 Snell/FIA certification and, quite likely, all manufacturer warranties apply to the headgear only in its “as manufactured” condition.

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RANDOM SAMPLE TESTING

            In addition to the certification testing, the Snell/FIA program 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 program will attempt to ensure that the helmets made available to the public continue to meet the performance requirements of this Standard.

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

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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.

          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 neither lessen the protective capability of the basic helmet 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 or inner surfaces of the helmet shell.

C.  Materials

          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. 

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.

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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 chin straps, 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 210°, an upward clearance of at least 7° and a downward clearance of at least 30°.  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 four-wheeled applications may permit helmets with more restricted visual fields.  For such helmets, a second set of peripheral vision requirements is specified.  The minimum horizontal, upward and downward requirements for this more restricted field are 180°, 5° and 20° respectively.   Helmets satisfying this visual field requirement but not the broader visual field specified generally are also subject to additional labeling requirements warning that the headgear is considered appropriate only for certain uses.

G.  Weight

          Permissible helmet weights depend on the smallest head circumference for which the helmet is intended.  The following table lists helmet weight limits for helmets configured without face shields.  If the helmet is configured with a face shield, the limit shall be 100 grams greater. 

Smallest size

not less than

Smallest size

less than

Maximum weight

(no face shield)

Maximum weight

(face shield)

-

50 cm

1000 grams

1100 grams

50 cm

52 cm

1050 grams

1150 grams

52 cm

54 cm

1100 grams

1200 grams

54 cm

57 cm

1150 grams

1250 grams

57 cm

60 cm

1200 grams

1300 grams

60 cm

-

1250 grams

1350 grams

 

Headgear shall be weighed in the most massive configuration possible with accompanying helmet paraphernalia.

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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.   The smallest and largest head circumferences for which the helmet is appropriate in centimeters.

4.   If the helmet does not satisfy the broader visual field requirements set for general use the helmet must be labeled to the following effect: “RESTRICTED VISUAL FIELD – MAY NOT BE APPROPRIATE FOR SOME ACTIVITIES”

          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 two Snell/FIA serialized CMH certification labels.  Helmets meeting only the narrower visual field requirement must include the special Snell/FIA label signifying that the helmet is intended only for certain activities.  Helmets meeting the broader visual field requirements may include either of the two labels. This 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, FIA, and the joint Snell/FIA mark may be used by the manufacturer only under license.  The specifics of licensure may be obtained from the Snell Memorial Foundation.

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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.

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Head Form

Circumference

Mass

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 cm

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 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.

 

 

Head form

Parameters

Designation

a

b

c

d

e

ISO A

39.0 mm

128.6 mm

26.1 mm

46.8 mm

52.2 mm

ISO C

40.6 mm

133.8 mm

27.2 mm

48.4 mm

54.3 mm

ISO E

42.2 mm

139.0 mm

28.2 mm

50.0 mm

56.4 mm

ISO J

45.2 mm

148.4 mm

30.0 mm

53.0 mm

60.0 mm

ISO M

47.4 mm

155.8 mm

31.5 mm

55.2 mm

63.0 mm

ISO O

49.2 mm

161.5 mm

32.2 mm

57.2 mm

 

 

 

 

TESTING

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A.  Helmet Positioning

          Each helmet will be positioned on the appropriate head forms for testing according to the helmet positioning indices specified.  If the manufacturer fails to provide positioning information with certification samples, the helmets will be positioned according to the best judgment of the authorized technical personnel.  If the helmets meet certification requirements, the helmet positioning indices will be those used in all future testing.

          These helmet positioning indices represent distances on the head form measured from the basic plane along the intersection with the longitudinal plane to the lower edge of the helmet.          Helmet positioning indices will be assigned for all head form sizes appropriate to the headgear.  Each headgear could conceivably require six helmet positioning indices, one each for the ‘A’, ‘C’, ‘E’, ‘J’, ‘M’ and ‘O’ head forms.

B.  Inspection

          Each helmet will be inspected for the required labels and for compliance with the general limitations made on structure.  The weight and various measurements will be recorded for comparison with other samples of the same make and model.  At least one headgear will be weighed in its most massive configuration.  The weight limits set for helmets depend on the smallest appropriate head circumference for which the helmet is intended and on whether the helmet is configured with a face shield.

Smallest size

not less than

Smallest size

less than

Maximum weight

(no face shield)

Maximum weight

(face shield)

-

50 cm

1000 grams

1100 grams

50 cm

52 cm

1050 grams

1150 grams

52 cm

54 cm

1100 grams

1200 grams

54 cm

57 cm

1150 grams

1250 grams

57 cm

60 cm

1200 grams

1300 grams

60 cm

-

1250 grams

1350 grams

 

At the discretion of the technician, additional helmet assemblies may be required to make this determination with appropriate levels of confidence.

          Some helmets may incorporate innovations and other features not anticipated by this Standard but which raise concerns about the safety and effectiveness of the headgear.  These will be referred to members of the Foundation's Board of Directors and/or authorities at the FIA for evaluation.  Any feature deemed to reduce the protective capacity of the headgear, whether explicitly mentioned in this Standard or not, will be a cause for rejection.

C.  Marking

           The helmet is placed upon the largest appropriate ISO head form, positioned according to the corresponding helmet positioning index and held in place with an applied force of 50 newtons (11.25 lbs).  If the helmet is configured with a movable face plate, the face plate shall be closed and latched.  The intersections of the shell with the various defined planes are then traced onto the outer surface of the helmet in the following manner:

          The level of the S0 plane is marked on that portion of the helmet in front of the fore plane.  The level of the S3 plane is marked on that portion lying between the fore and rear planes.  The level of the S4 plane is marked on that portion behind the rear plane.  Finally, line segments along the fore plane are marked to join the S0 and S3 planes and, similarly, line segments along the rear plane are marked to join the S3 and S4 planes. 

          These lines enclose the top of the helmet and are the boundary of the required extent of protection.  However, it shall not be a cause for rejection if parts of this boundary fall below the edge of the helmet.  A test line shall be constructed within the extent of protection 40 mm from the closest point on the boundary as shown in figure 2.

          If identical helmets are to be configured with different thicknesses of comfort padding to accommodate different ranges of head size, the required extent of protection marked on the test samples shall include the required extent of protection for each different configuration as marked on the largest head form appropriate for each.  That is:  the helmet must meet all of the requirements of this Standard in each of the intended configurations.

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D. Shell Edge Lower Limit

          Helmets shall be placed upon the smallest appropriate ISO head form, positioned according to the corresponding helmet positioning index and held in place with an applied force of 50 newtons (11.25 lbs).  If the helmet is configured with a moveable face plate, the face plate shall be closed and latched.  The vertical distance from the basic plane of the head form to the lowest point on the helmet shell shall be measured at the front and rear in the midsagittal plane and right and left in the transverse plane.  This measurement shall include edge beading but shall not include any helmet comfort and fit padding which may protrude below the edges of the helmet shell. This distance shall not exceed 14.0 cm in front, 9.0 cm on the right and left, nor 4.0 cm in the rear.

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E. Peripheral Vision

          The clearance for peripheral vision will be checked by placing the helmet on each appropriate ISO head form, positioning it according to the corresponding helmet positioning index and holding it in place with a force of 50 newtons.  The clearance must include the following solid angles to the front of the head form:

          1. The upward visual clearance.

          2.  The lateral visual clearance.

          3.  The downward visual clearance except for the breath deflector allowance.

          The upward visual clearance is the solid angle bounded by the reference plane of the head form and a second plane tilted up from the reference plane.  This angle is 7° for the general requirements and 5° for the restricted vision requirement. The second plane intersects the reference plane at two points on the front surface of the head form that are 31 mm to the right and left of the longitudinal plane as shown in figures 3 and 3b. 

          The general requirement for lateral visual clearance is shown in figure 4. It is the solid angle bounded by the reference plane, the S4 plane and two more planes that are perpendicular to the reference plane and lie to the right and left, respectively.  These right and left planes pass through the head forms reference point and form angles of 105° with the longitudinal plane. The restricted visual field requirement is shown in figure 4b.  Here, the right and left planes are coplanar and perpendicular to the longitudinal plane and the reference plane.  The right and left planes intersect the front of the head form at points on the reference plane and 31 mm to the right and left of the longitudinal plane.

 


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The downward visual clearance is the solid angle bounded by the basic plane of the head form and a second plane tilted down from the basic plane and that intersects it at two points on the front surface of the head form that are 31 mm to the right and left of the longitudinal plane as shown in figures 5 and 5b.  The degree of downward tilt is 30° for the general requirement and 20° for the restricted visual field requirement.  However, intrusions into these downward clearances are permitted so long as the intrusions are within the breath deflector allowance.

          The breath deflector allowance is shown in figure 6.  It includes the region that is within 31 mm to the right and left of the longitudinal plane and that lies below the two planes that form 45° angles with the longitudinal plane and that intersect it at the level of the S4 plane.

In order to meet the general visual field requirements,      no part of the helmet except the face shield may intrude into the solid angles shown in figures 3 and 4 nor into those parts of the solid angle in figure 5 outside the breath deflector allowance.  In order to meet the restricted visual field requirements, no part of the helmet except the face shield may intrude into the solid angles shown in figures 3b and 4b not into those parts of the solid angle in figure 5b outside the breath deflector allowance.  These requirements do not apply to face shield fixtures such as hold tear-off

shields.

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F.  Performance Testing

          The performance testing subjects helmets to:

      A dynamic test of retention system strength.

      A test for positional stability.

      Impact management tests.

      Helmet shell penetration tests.

      A removability test

      And to chin bar and face shield tests if appropriate. 

          These tests are conducted upon helmet samples kept under laboratory ambient temperature and humidity or that have been conditioned in one of three environments simulating some of the conditions in which the helmet might reasonably be expected to be used.

          Prior to conditioning and testing, samples may be exposed to solvents common to motor sports which have been found to attack and degrade some helmet components.

          In certification testing, the first of the four samples is kept at laboratory ambient temperature and humidity and allowed to come to equilibrium.  It is subjected first to the positional stability test and then to the impact management and other tests.  The second, third and fourth samples are conditioned hot, cold and wet, and subjected to the dynamic test of the retention system, the impact management test and the other tests.

          The selection of tests, conditioning and special conditioning is left to the discretion of the authorized technical personnel.  However, for certification testing, each of the specified tests shall be applied to at least one sample.  Furthermore, it is expected that all testing will be conducted so as to exercise all the likely failure modes of the helmet.

F1.  Conditioning for Testing

           Test samples may be kept at laboratory ambient temperature and humidity or may be conditioned either cold, hot or wet according to the specifications given below.  At the discretion of the authorized technical personnel and at any point during the testing, a sample previously kept at ambient may be conditioned cold, hot or wet.  However, once a sample has been conditioned cold, hot or wet, the sample must be maintained in that condition throughout the rest of the testing.

          The special solvent wipe conditioning described below may be applied to any sample at the discretion of the authorized technical personnel. 

          a. Special Conditioning.  Prior to any impact or retention system testing helmets may first be conditioned with a solvent mix of 50% toluene and 50% isooctane.  A cotton cloth or suitable substitute shall be soaked in the solvent and used as an applicator.  The solvent will be applied to the shell first in an area within 5 mm of the chin strap attachments for not less than five (5) seconds on each side and then applied to the remainder of the shell for not less than ten (10) seconds.  At least thirty minutes shall elapse before further conditioning and testing.

          b. Cold.  The sample shall be conditioned by being exposed to a temperature of -20 ±2° C for a period of not less than four (4) hours, nor more than twenty-four (24) hours.

          c. Heat.  The sample shall be conditioned by being exposed to a temperature of 50 ±2° C for a period of not less than four (4) hours, nor more than twenty-four (24) hours.

          d. Wet.  The sample shall be conditioned by being continuously sprayed with water at a temperature of 25 ±5° C for a period of not less than four (4) hours, nor more than twenty-four (24) hours.  This spray shall be directed at the helmet's external surfaces.  The helmet shall not be subjected to total immersion.

           All testing of these hot, cold and wet helmets shall begin within two (2) minutes from the time of removal from the conditioning apparatus.  The samples shall be returned to the conditioning apparatus between tests.

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F2.  Positional Stability (Roll-Off)

          The test for positional stability shall only be applied to samples kept at ambient laboratory temperature and humidity.  The helmet shall not have been subjected to any prior performance testing.

          The helmet shall be tested on the smallest appropriate standard full-face head form.  The head form shall be supported on a stand so that its vertical axis points downward at an angle of 135° to the direction of gravity.  The head form shall be oriented face down.  The helmet shall be placed on the head form and adjusted to obtain the best configuration of the retention system.  A non-elastic strap shall be hooked to the edge of the helmet at the rear centerline and brought forward so that its free end hangs downward across the top of the helmet.  An inertial hammer shall be suspended from the free end of the strap.  This inertial hammer shall enable a 4.0 kg ±50 g mass to be dropped through a 0.6 m guided fall in order to deliver an abrupt shock load to the headgear.  The shock load will force the helmet to rotate forward on the head form.  The helmet may be shifted but must remain on the head form. 

          The head form shall be repositioned so that it is facing upward but with the vertical axis still oriented downward at 135° to gravity.  The helmet shall be positioned and adjusted to obtain the best configuration of the retention system.  The strap/inertial hammer shall be hooked to the brow edge of the helmet at the center line so that the strap lies along the centerline and the hammer is suspended from the top of the helmet.  The shock weight shall be dropped through the 0.6 m guided fall delivering an abrupt shock load forcing the helmet to rotate rearward.  The helmet may be shifted but must remain on the head form.

          The entire portion of the inertial hammer assembly that participates in the loading of the helmet shall be such that its mass is no more than 5.0 kg including the 4.0 kg shock mass.

F3.  Dynamic Test of Retention System

          The dynamic test of the retention system may be applied to any sample either kept at ambient temperature and humidity or conditioned hot, cold or wet.  This test may be performed before, after, or between any of the other procedures in the test sequence.  However, the retention test shall not be valid if an integral chin bar has been removed from a full face helmet. 

          The helmet shall be placed on the largest appropriate head form in such a manner that the chin strap may be fastened under a device whose upper end approximates the contour of the bony structure of the jaw.  The device will then be given a mechanical pre-load followed by a dynamic loading.  The retention system fails if it cannot support the mechanical loads or if the maximum deflection during the dynamic load exceeds 30 mm.  The retention system also fails if it cannot be easily and quickly unfastened after testing. 

          a. This chinstrap loading device shall consist of a simulated jaw and accommodations for the pre-load and dynamic load.  The jaw portion shall consist of two metal bars or rollers, each one 12.7 ±0.5 mm in diameter, separated by 76 ±0.5 mm on center.  The mass of this device shall not exceed 6.0 kg.

          b. A pre-load shall be applied for at least 60 seconds.  This pre-load plus the mass of the chinstrap loading device shall total 23 kg±500 g.

          c. A 38 kg±500 g mass shall be dropped in a vertical guided fall a distance of 120 mm so as to load the retaining system abruptly; the 38 kg mass and pre-load mass shall not be additive.  In order to protect the test mechanism, the impact of the 38 kg mass may be cushioned with a 00-93 durometer rubber pad 150 mm in diameter by 6½ mm thick, or its equivalent.

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F4.  Impact Management Tests

          The impact management tests may be performed on samples kept at ambient temperature and humidity or conditioned hot, cold or wet.  The sample shall not have been subjected to the shell penetration test beforehand.

          These tests involve a series of controlled impacts in which the helmet is positioned on a test head form.  The helmeted head form is then dropped in guided falls onto specified test anvils.  The impact site and the impact velocity must meet certain requirements in order for the tests to be valid.

          If the sample is so constructed that it interferes with the test equipment preventing impacts at sites within the test line, then, at the discretion of the authorized technical personnel, parts of the helmet may be cut away to facilitate testing.  Every reasonable effort to minimize such cutting will be made.  However, there shall be no relaxation of the impact levels or of the test criteria.

          Certain tests shall not be valid when performed on samples that have been cut for impact testing: the dynamic strength of retention system test of section F3., the positional stability test of section F2., the chin bar test of section F5. and the removability test of section F8. 

          Special considerations apply when the helmet is a ‘flip-up’ model, that is: configured with a chin bar that pivots up and away from the face of the wearer.  Whenever possible, the impact tests will be performed with the chin bar locked in the closed position.  In these tests, in addition to all the other test criteria, the chin bar must not release and ‘flip-up’ inadvertently.

F4.1   Impact Management Test Equipment

          The test equipment shall consist of at least the following items:

          a.  The smallest and largest of the head forms appropriate for the helmet sample.  This head form shall be of rigid, low resonance metal such as magnesium alloy and shall conform to the ‘A’, ‘C’, ‘E’, ‘J’, ‘M’ or ‘O’ geometries specified in ISO DIS 6220-1983.

          b.  A ball-arm/collar assembly which is fitted to a socket machined into the base of the head form.  The ball/socket configuration shall be such that the geometrical center of the ball is located on the central vertical axis of the head form 12.7 mm above the reference plane as described in ISO DIS 6220-1983.  The ball-arm/collar assembly shall also include a uniaxial accelerometer fixed firmly into the ball.

          c. A head form support assembly rigidly attached to the ball-arm.  This support assembly shall be such that it and consequently the head form may be guided in a vertical drop.  The mass of this support assembly shall not exceed 1.2 kg.  The total mass of the head form plus ball-arm/collar assembly plus head form support assembly shall be within 100 grams of: 3.1 kg for the ISO A head form, 3.6 kg for the ISO C head form, 4.1 kg for the ISO E head form, 4.7 kg. for the ISO J head form, 5.6 kg. for the ISO M head form and 6.1 kg. for the ISO O head form.

          d. A guidance system such that the head form/support assembly is guided in a vertical drop onto a test anvil.  This guidance system may consist of two or more wires or one or more rails.  The head form/support - guidance system - test anvil alignment shall be such that:

          d1.  The drop trajectory shall be a straight line within 3° of vertical and within 5° of the sensitive axis of the uniaxial accelerometer.

          d2.  The line parallel to the drop trajectory and passing through the center of the head form ball-socket shall pass within 5 mm of the center of the test anvil, within 10 mm of the center of gravity of the head form/support assembly, and within 5 mm of the sensitive element of the uniaxial accelerometer. 

          e. A rigid anvil mount consisting of a solid mass of at least 500 kg.  The upper surface of the anvil mount shall consist of a steel plate with a minimum thickness of 12 mm and a minimum surface area of 0.10 m2.

          f. Three test anvils: flat, hemispherical and edge. 

          f1.  The flat anvil shall have a minimum surface area of 0.0127 m2, e.g. 127 mm diameter face.  When fixed in position on the anvil mount, the surface shall be perpendicular to the head form trajectory.

          f2.  The hemispherical anvil shall have a 48 ±0.5 mm radius. 

          f3.  The edge anvil shall have a striking face 6.3 ±0.5 mm wide by at least 180 mm long with a depth of at least 35 mm.  When in position, the striking face shall be perpendicular to the head form trajectory.

          g. A uniaxial accelerometer.  The acceleration data channel must comply with SAE recommended practice J 211 requirements for channel class 1000 with the exception that the frequency response need not include the range from dc to 10 hz which may not be obtainable using certain types of transducers.

          h. A velocity measurement device which will yield the velocity of the head form/support assembly within the last 40 mm of travel before impact.  The velocity measurements must be accurate to within ±1%. 

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F4.2   Test Definitions

          a. The impact site refers to the portion of the helmet struck during an impact test.  It is defined as the point where a line passing through the center of the head form ball and the center of the anvil intersects the outer surface of the helmet at the instant the helmet first touches the anvil.

          b. The impact velocity is the velocity of the head form/support assembly as measured within no more than 3 cm of the first contact between the helmet and the impact surface.

          c. There are two levels of test: the first is the standard level used to identify those helmets which definitely meet this standard.  It is applied to samples submitted for certification testing and to those acquired for the Foundation’s random sample test (RST) program.  The second is the deviation level which is applied to samples acquired for second round RST procedures, that is: testing of samples of currently certified models for which previous samples have obtained failing results in RST testing.   Failure to meet test criteria at the deviation levels indicates that the sample definitely does not meet the requirements of the standard.

F4.3 Test Impacts

          Test impact sites shall be on or above the test line.  Rivets, vents and any other helmet feature within this region shall be valid test sites.  Each impact site will be subjected to a group of one or two impacts according to the anvil selected for that site.

          The impact site for the first impact within a group is the target for the successive impacts in the same group.  However, if an impact group is sited closer than 120 mm to any previous impact group, that later impact shall be declared invalid. 

          There is no restriction regarding test anvil selection.           The technician may select either the largest or smallest appropriate head form for any particular group of impacts.  In all cases the technician may impact any site on the helmet surface on or within the test lines as drawn for any of the head forms considered appropriate for that helmet.

 

Impact Velocities

Certification

1st

7.75 m/s

2nd

6.00 m/s

Deviation

1st

7.48 m/s

2nd

5.80 m/s

 

a. Each site tested against the flat anvil shall be tested according to the values in the impact velocity table.

b. Each site tested against the hemispherical anvil shall be tested according to the values in the impact velocity table.

          c. Each site tested against the edge anvil shall be tested according to the values in the impact velocity table.  No helmet shall be subjected to the second impact for this anvil.

          d. If the impact velocity for any test impact exceeds the velocity specified by more than 1.5%, that impact shall be declared invalid.

          Please Note: The impacts described above are based on specific velocities and not prescribed drop heights.  To attain the proper velocity for an impact, it is likely that the drop height will need to be adjusted to compensate for frictions inherent in most mechanical helmet testing systems. Height adjustments for these frictions should not account for more than 10% of the total drop height.  Also, the 1.5% margin allowed for impact velocity reflects the uncertainties expected even for well maintained drop equipment.  It is expected that drop heights will always be selected to produce, as closely as possible, the precise impact velocities called out in the standards.

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F4.4   Impact Test Interpretation

          The peak acceleration of the head form shall not exceed 290 G’s for any valid certification impact nor 300 G's for any other valid test impact.  The helmet’s protective structures shall not break apart throughout the testing.  If the authorized technical personnel conclude that fracture of the helmet shell, impact liner, retention system or other components could reasonably imply an undue laceration hazard either from the impact surface or from the helmet itself, the sample shall be considered to have failed.  A flip-up configuration tested with the chin bar closure locked at the outset of a valid impact and which releases inadvertently as a result of the impact will also be deemed to have failed.

          If, in certification testing, a sample is found to meet all the test criteria but any two of the impacts were at less than 98% of the impact velocity specified, the testing for that sample shall be declared inconclusive and must be repeated.  Similarly, if there are two instances where an impact falls beyond 10 mm from the first impacts in its group, the testing for the sample shall be declared inconclusive and must be repeated.  Finally, if an invalid impact produces a peak acceleration exceeding the test criterion, the testing for the sample shall be declared inconclusive and must be repeated.

          The impact test procedures leave considerable latitude to the helmet tester regarding site and anvil selection.  It is expected that the tester will orchestrate each standard test series in order to investigate potential weaknesses and to exercise each likely failure mode and will conduct deviation level testing to exercise the failure modes identified previously.

          If at the end of a certification test series, the authorized technical personnel conclude that the results obtained in valid impacts are not sufficient to determine whether the helmet model meets the performance requirements of this standard, additional samples may be conditioned and tested.  It is expected that all samples submitted will meet all the test requirements.

F5.  Chin Bar Tests

          There are two tests for facial protection:

F5.a.  Chin Bar Rigidity

          At least one helmet in each certification series shall be tested.  The sample shall not have been previously tested in chin bar impact.  The helmet shall be firmly mounted on a rigid base so that the chin bar faces up and the reference plane is at 65 ± 5° from horizontal.  A mass of 5 ± .2 kg with a flat striking face of 0.01 m² minimum area shall be dropped in a guided fall so as to strike the central portion of the chin bar with an impact velocity of 3.5 ±0.2 m/sec.  The maximum downward deflection of the chin bar must not exceed 60 mm nor any component fail so as to cause a potential injury to the wearer.

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F5.b.  Chin Bar Impact

          At least one helmet in each certification series shall be tested.  The sample shall not have previously been tested in chin bar rigidity, retention strength or in positional stability.  The helmet shall be placed upon the appropriate full face head form and the chin strap shall be firmly secured beneath the head form’s chin.  Reasonable effort shall be made to position the helmet according to the correct helmet positioning index (HPI).  The helmet shall then be tested in a guided free fall in the following manner:

          The helmet shall be placed in a special cradle which can move downward freely along guide wires or one or more rigid rails delivering its contents to impact against a flat anvil such as described in paragraph f1. of section F4.1 of this standard.  The helmet shall be positioned in the cradle in such a manner that the helmet’s longitudinal plane is within 3º of vertical and the helmet’s Z axis is tilted to 65º ± 3º.  The planes and axes of the helmet coordinate system correspond to those of the appropriate head form when the helmet is placed on the head form, held in place with a force of 50 newtons applied to its crown and positioned according to its established helmet positioning index.  If the impact point will be within 15 mm of the rim, the helmet and head form shall be repositioned so that the impact point is not less than 15 mm from the rim.  Once the helmet and head form have been positioned in the cradle, the helmet may be secured to the cradle by strapping with Velcro closures or some comparable mechanism that will release reliably at the onset of impact.

            The cradle with the helmet and head form shall be dropped along the guides such that the chin bar will strike the flat anvil.  The velocity of the falling cradle shall be measured in the manner described in paragraph h. of section F4.1 of this standard. The shock acceleration at the design center of gravity of the head form shall be measured by means of a tri-axial accelerometer and data recording system meeting the requirements of SAE J211 S. 

            If the impact velocity measurement is 5.5 m/s or more and the peak magnitude of the recorded acceleration of the head form is 275 G or less, the sample shall be deemed to meet the test requirement.  If the impact velocity is less than 5.65 m/s and the peak magnitude of the acceleration exceeds 275 G, the sample shall be deemed not to meet the test requirement.  If the test measurements do not meet one of these two conditions, the test is inconclusive and must be repeated.

F6.  Shell Penetration Test

          The shell penetration test may be applied to helmets kept at laboratory ambient temperature and humidity or helmets conditioned hot, cold or wet. At least one helmet sample shall be tested in shell penetration.  The complete helmet shall be placed on a rigidly mounted head form.  The test head form for the penetration test need not be the standard ISO head form shape used in the impact testing and helmet marking.  It is expected only that the device used will provide reasonable support for the helmet and conformance with the interior of the helmet immediately beneath the site of the penetration test.  If the helmet contains a sling or some other adjustable sizing component, it shall be relaxed to its most extendable position.

          The penetration test striker shall have a mass of 3 kg ±50 g.  The striker shall fall through a height of 3 m ±15 mm.  The point of the striker shall be a cone with an included angle of 60° ±0.5° and an altitude of 38 ±0.38 mm.  The striking tip shall have a hardness of 60 Rockwell (scale C ±3 points) and a radius of .5 ±.01 mm.

          The test striker may be directed at any site on or above the test line but the penetration test site must be at least 7.5 cm removed from the center of any impact test site or any other penetration test site.  At the test technician’s discretions, samples may be tested at more than one site on the shell.

          For all penetration tests performed, the test striker must not penetrate to achieve even momentary contact with the test head form.

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F7.  Face Shield Penetration Test

          If a face shield is provided, this face shield shall be tested for penetration resistance in the following manner:

          The face shield shall be tested on the appropriate helmet, correctly deployed across the facial opening and under laboratory ambient conditions.  A soft lead pellet weighing 1 ±0.1 g with a diameter of 5.5 ±0.1 mm and traveling at a velocity of 500 ±20 km per hour shall strike the face shield normal to the surface.  The face shield shall be tested in at least three different locations:  the center line and 80 ±5 mm to either side of the center line.  The pellet must not penetrate to the interior of the helmet.

F8.  Removability

          The helmet removability test determines whether the helmet can be removed from an unconscious victim without resorting to any buckles, clasps or other mechanisms which may be rendered non-functional by impact stresses.  The helmet is placed on the largest appropriate complete ISO head form with all the closures and retention systems engaged.  A technician must remove the helmet from the head form using simple, common hand tools but without accessing any of the helmet mechanisms.

          The hand tools for this test are limited to shears, simple edged tools and flat bladed screw drivers.  The operation must not require more than thirty seconds.

F9.  Post-testing Disassembly and Inspection

          If a set of helmets is submitted for and passes certification testing, one or more the tested samples shall be disassembled and inspected.  If any of the helmet samples appear to have been specially configured to meet test requirements and are not reasonably representative of an economically viable production helmet, the model shall be rejected.  In particular, samples must not be configured with extra layers of hand cut padding and materials inserted between shell and liner or applied to the inner surface of the liner.  Elements such as these may confer an advantage in satisfying test requirements but are all too likely to be left out of production units afterwards.

           If an internal projection on the helmet shell is deemed to present an undue laceration or puncture hazard, the model shall be rejected.  In evaluating these internal projections, no allowance shall be made for liner thickness.

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     1     The Foundation has also published Standards for headgear used in bicycling, non-motorized sports, automobile racing, karting, competitive skiing, skiing and snowboarding and equestrian activities.  Copies of these Standards are available upon request.