The Snell
Memorial Foundation is an additional certification source intended to
provide testing standards and "Snell" certification to a
different standard than FMVSS 218. The Snell
standards don't replace the DOT standards; meeting Snell standards
is completely voluntary. All
motorcycle helmets sold in the U.S.A. must be DOT "certified", in
that they must have gone through the proper procedures in a
certified testing lab to meet DOT standards for motorcycle helmets,
but they are not required to be Snell certified.
A motorcycle helmet that
carries both DOT and Snell standards may have gone through different
testing schemes, but may not necessarily be superior to helmets that
meets the DOT standard. There is some controversy over
standards and testing, and it gets even more complicated if you consider
the European ECE 22.05 standard.
See also the new
SHARP motorcycle helmet rating system used in the
UK.
Code of Federal Regulations
Title 49, Volume 5 - Revised as of October 1, 2001
CITE: 49CFR571.218
[Page 643-659]
TITLE 49--TRANSPORTATION
CHAPTER V--NATIONAL HIGHWAY TRAFFIC
SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION
PART 571--FEDERAL MOTOR VEHICLE SAFETY
STANDARDS--Table of Contents
Subpart B--Federal Motor Vehicle
Safety Standards
Sec. 571.218 Standard No. 218;
Motorcycle helmets.
S1. Scope. This standard establishes minimum performance
requirements for helmets designed for use by motorcyclists and other
motor vehicle users.
S2. Purpose. The purpose of this standard is to
reduce deaths and injuries to motorcyclists and other
motor vehicle users resulting from head impacts.
S3. Application. This standard applies to all helmets
designed for use by motorcyclists and other motor
vehicle users.
S4. Definitions.
-
Basic plane means a plane
through the centers of the right and left external
ear openings and the lower edge of the eye sockets (Figure 1) of a reference
headform (Figure 2) or test headform.
-
Helmet positioning index means the
distance in inches, as specified by the manufacturer, from the lowest
point of the brow opening at the lateral midpoint of the helmet to the
basic plane of a reference headform, when the helmet is firmly and
properly positioned on the reference headform.
-
Midsagittal plane means a
longitudinal plane through the apex of a reference headform or test
headform that is perpendicular to the basic plane (Figure 3).
-
Reference headform means a measuring device contoured to the dimensions of one of
the three headforms described in Table 2 and Figures 5 through 8 with
surface markings indicating the locations of the basic, mid-sagittal,
and reference planes, and the centers of the external ear openings.
-
Reference plane means a plane above and parallel to the basic plane on a
reference headform or test headform (Figure 2) at the distance indicated
in Table 2.
-
Retention system means the complete assembly by which the
helmet is retained in position on the head during use.
-
Test headform
means a test device contoured to the dimensions of one of the three
headforms described in Table 2 and Figures 5 through 8 with surface
markings indicating the locations of the basic, mid-sagittal, and
reference planes.
S5. Requirements. Each helmet shall meet the
requirements of S5.1, S5.2, and S5.3 when subjected to any conditioning
procedure specified in S6.4, and tested in accordance with S7.1, S7.2,
and S7.3.
S5.1 Impact attenuation. When an impact attenuation test is
conducted in accordance with S7.1, all of the following requirements
shall be met: (a) Peak accelerations shall not exceed 400g; (b)
Accelerations in excess of 200g shall not exceed a cumulative duration
of 2.0 milliseconds; and (c) Accelerations in excess of 150g shall not
exceed a cumulative duration of 4.0 milliseconds. S5.2 Penetration. When
a penetration test is conducted in accordance with S7.2, the striker
shall not contact the surface of the test headform.
S5.3 Retention
system.
S5.3.1 When tested in accordance with S7.3: (a) The retention
system or its components shall attain the loads specified without
separation; and (b) The adjustable portion of the retention system test
device shall not move more than 1 inch (2.5 cm) measured between
preliminary and test load positions.
S5.3.2 Where the retention system
consists of components which can be independently fastened without
securing the complete assembly, each such component shall independently
meet the requirements of S5.3.1.
S5.4 Configuration. Each helmet shall
have a protective surface of continuous contour at all points on or
above the test line described in S6.2.3. The helmet shall provide
peripheral vision clearance of at least 105 deg. to each side of the
mid-sagittal plane, when the helmet is adjusted as specified in S6.3.
The vertex of these angles, shown in Figure 3, shall be at the point on
the anterior surface of the reference headform at the intersection of
the mid-sagittal and basic planes. The brow opening of the helmet shall
be at least 1 inch (2.5 cm) above all points in the basic plane that are
within the angles of peripheral vision (see Figure 3).
S5.5 Projections.
A helmet shall not have any rigid projections inside its shell. Rigid
projections outside any helmet's shell shall be limited to those
required for operation of essential accessories, and shall not protrude
more than 0.20 inch (5 mm).
S5.6 Labeling.
S5.6.1 Each helmet shall be
labeled permanently and legibly, in a manner such that the label(s) can
be read easily without removing padding or any other permanent part,
with the following:
-
(a) Manufacturer's name or identification.
-
(b)
Precise model designation.
-
(c) Size.
-
(d) Month and year of manufacture.
This may be spelled out (for example, June 1988), or expressed in numerals (for
example, 6/88).
-
(e) The symbol DOT, constituting the manufacturer's
certification that the helmet conforms to the applicable Federal motor
vehicle safety standards. This symbol shall appear on the outer surface,
in a color that contrasts with the background, in letters at least \3/8\
inch (1 cm) high, centered laterally with the horizontal centerline of
the symbol located a minimum of 1\1/8\ inches (2.9 cm) and a maximum of
1\3/ 8\ inches (3.5 cm) from the bottom edge of the posterior portion of
the helmet.
-
(f) Instructions to the purchaser as follows:
-
(1) ``Shell
and liner constructed of (identify type(s) of materials).
-
(2) ``Helmet
can be seriously damaged by some common substances without damage being
visible to the user. Apply only the following: (Recommended cleaning
agents, paints, adhesives, etc., as appropriate).
-
(3) ``Make no
modifications. Fasten helmet securely. If helmet experiences a severe
blow, return it to the manufacturer for inspection, or destroy it and
replace it.''
-
(4) Any additional relevant safety information should be
applied at the time of purchase by means of an attached tag, brochure,
or other suitable means.
S5.7 Helmet positioning index. Each
manufacturer of helmets shall establish a positioning index for each
helmet he manufactures. This index shall be furnished immediately to any
person who requests the information, with respect to a helmet identified
by manufacturer, model designation, and size.
S6. Preliminary test
procedures. Before subjecting a helmet to the testing sequence specified
in S7., prepare it according to the procedures in S6.1, S6.2, and S6.3.
S6.1 Selection of appropriate headform.
S6.1.1 A helmet with a
manufacturer's designated discrete size or size range which does not
exceed 6\3/4\ (European size: 54) is tested on the small headform. A
helmet with a manufacturer's designated discrete size or size range
which exceeds 6\3/4\, but does not exceed 7\1/2\ (European size: 60) is
tested on the medium headform. A helmet with a manufacturer's designated
discrete size or size range which exceeds 7\1/ 2\ is tested on the large
headform.
S6.1.2 A helmet with a manufacturer's designated size range
which includes sizes falling into two or all three size ranges described
in S6.1.1 is tested on each headform specified for each size range. S6.2
Reference marking.
S6.2.1 Use a reference headform that is firmly seated
with the basic and reference planes horizontal. Place the complete
helmet to be tested on the appropriate reference headform, as specified
in S6.1.1 and S6.1.2.
S6.2.2 Apply a 10-pound (4.5 kg) static vertical
load through the helmet's apex. Center the helmet laterally and seat it
firmly on the reference headform according to its helmet positioning
index.
S6.2.3 Maintaining the load and position described in S6.2.2,
draw a line (hereinafter referred to as ``test line'') on the outer
surface of the helmet coinciding with portions of the intersection of
that service with the following planes, as shown in Figure 2: (a) A
plane 1 inch (2.5 cm) above and parallel to the reference plane in the
anterior portion of the reference headform; (b) A vertical transverse
plane 2.5 inches (6.4 cm) behind the point on the anterior surface of
the reference headform at the intersection of the mid-sagittal and
reference planes; (c) The reference plane of the reference headform; (d)
A vertical transverse plane 2.5 inches (6.4. cm) behind the center of
the external ear opening in a side view; and (e) A plane 1 inch (2.5 cm)
below and parallel to the reference plane in the posterior portion of
the reference headform.
S6.3 Helmet positioning.
S6.3.1 Before each
test, fix the helmet on a test headform in the position that conforms to
its helmet positioning index. Secure the helmet so that it does not
shift position before impact or before application of force during
testing.
S6.3.2 In testing as specified in S7.1 and S7.2, place the
retention system in a position such that it does not
interfere with free fall, impact or penetration.
S6.4 Conditioning.
S6.4.1 Immediately before conducting the testing sequence specified in
S7, condition each test helmet in accordance with any one of the
following procedures: (a) Ambient conditions. Expose to a temperature of
70 deg.F(21 deg.C) and a relative humidity of 50 percent for 12 hours.
(b) Low temperature. Expose to a temperature of 14 deg.F(-10 deg.C) for
12 hours. (c) High temperature. Expose to a temperature of 122 deg.F(50
deg.C) for 12 hours. (d) Water immersion. Immerse in water at a
temperature of 77 deg.F(25 deg.C) for 12 hours.
S6.4.2 If during
testing, as specified in S7.1.3 and S7.2.3, a helmet is returned to the
conditioning environment before the time out of that environment exceeds
4 minutes, the helmet is kept in the environment for a minimum of 3
minutes before resumption of testing with that helmet. If the time out
of the environment exceeds 4 minutes, the helmet is returned to the
environment for a minimum of 3 minutes for each minute or portion of a
minute that the helmet remained out of the environment in excess of 4
minutes or for a maximum of 12 hours, whichever is less, before the
resumption of testing with that helmet.
S7. Test conditions.
S7.1 Impact
attenuation test.
S7.1.1 Impact attenuation is measured by determining
acceleration imparted to an instrumented test headform on which a
complete helmet is mounted as specified in S6.3, when it is dropped in
guided free fall upon a fixed hemispherical anvil and a fixed flat steel
anvil.
S7.1.2 Each helmet is impacted at four sites with two successive
identical impacts at each site. Two of these sites are impacted upon a
flat steel anvil and two upon a hemispherical steel anvil as specified
in S7.1.10 and S7.1.11. The impact sites are at any point on the area
above the test line described in paragraph S6.2.3, and separated by a
distance not less than one-sixth of the maximum circumference of the
helmet in the test area.
S7.1.3 Impact testing at each of the four
sites, as specified in S7.1.2, shall start at two minutes, and be
completed by four minutes, after removal of the helmet from the
conditioning environment.
S7.1.4 (a) The guided free fall drop height
for the helmet and test headform combination onto the hemispherical
anvil shall be such that the minimum impact speed is 17.1 feet/second
(5.2 m/sec). The minimum drop height is 54.5 inches (138.4 cm). The drop
height is adjusted upward from the minimum to the extent necessary to
compensate for friction losses. (b) The guided free fall drop height for
the helmet and test headform combination onto the flat anvil shall be
such that the minimum impact speed is 19.7 ft./sec (6.0 m/sec). The
minimum drop height is 72 inches (182.9 cm). The drop height is adjusted
upward from the minimum to the extent necessary to compensate for
friction losses.
S7.1.5 Test headforms for impact attenuation testing
are constructed of magnesium alloy (K-1A), and exhibit no resonant
frequencies below 2,000 Hz.
S7.1.6 The monorail drop test system is used
for impact attenuation testing.
S7.1.7 The weight of the drop assembly,
as specified in Table 1, is the combined weight of the test headform and
the supporting assembly for the drop test. The weight of the supporting
assembly is not less than 2.0 lbs. and not more than 2.4 lbs. (0.9 to
1.1 kg). The supporting assembly weight for the monorail system is the
drop assembly weight minus the combined weight of the test headform, the
headform's clamp down ring, and its tie down screws.
S7.1.8 The center
of gravity of the test headform is located at the center of the mounting
ball on the supporting assembly and lies within a cone with its axis
vertical and forming a 10 deg. included angle with the vertex at the
point of impact. The center of gravity of the drop assembly lies within
the rectangular volume bounded by x = -0.25 inch (-0.64 cm), x = 0.85
inch (2.16 cm), y = 0.25 inch (0.64 cm), and y = -0.25 inch (-0.64 cm)
with the origin located at the center of gravity of the test headform.
The rectangular volume has no boundary along the z-axis. The x-y-z axes are mutually perpendicular and
have positive or negative designations in accordance with the right-hand
rule (See Figure 5). The origin of the coordinate axes also is located
at the center of the mounting ball on the supporting assembly (See
Figures 6, 7, and 8). The x-y-z axes of the test headform assembly on a
monorail drop test equipment are oriented as follows: From the origin,
the x-axis is horizontal with its positive direction going toward and
passing through the vertical centerline of the monorail. The positive
z-axis is downward. The y-axis also is horizontal and its direction can
be decided by the z- and x-axes, using the right-hand rule.
S7.1.9 The
acceleration transducer is mounted at the center of gravity of the test headform with the sensitive axis aligned to within 5 deg. of vertical
when the test headform assembly is in the impact position. The
acceleration data channel complies with SAE Recommended Practice J211
JUN 80, Instrumentation for Impact Tests, requirements for channel class
1,000.
S7.1.10 The flat anvil is constructed of steel with a 5-inch
(12.7 cm) minimum diameter impact face, and the hemispherical anvil is
constructed of steel with a 1.9 inch (4.8 cm) radius impact face.
S7.1.11 The rigid mount for both of the anvils consists of a solid mass
of at least 300 pounds (136.1 kg), the outer surface of which consists
of a steel plate with minimum thickness of 1 inch (2.5 cm) and minimum
surface area of 1 ft.2 (929 cm2 ).
S7.1.12 The drop system
restricts side movement during the impact attenuation test so that the
sum of the areas bounded by the acceleration-time response curves for
both the x- and y-axes (horizontal axes) is less than five percent of
the area bounded by the acceleration- time response curve for the
vertical axis.
S7.2 Penetration test.
S7.2.1 The penetration test is
conducted by dropping the penetration test striker in guided free fall,
with its axis aligned vertically, onto the outer surface of the complete
helmet, when mounted as specified in S6.3, at any point above the test
line, described in S6.2.3, except on a fastener or other rigid
projection.
S7.2.2 Two penetration blows are applied at least 3 inches
(7.6 cm) apart, and at least 3 inches (7.6 cm) from the centers of any
impacts applied during the impact attenuation test. S7.2.3 The
application of the two penetration blows, specified in S7.2.2, starts at
two minutes and is completed by four minutes, after removal of the
helmet from the conditioning environment.
S7.2.4 The height of the
guided free fall is 118.1 inches (3 m), as measured from the striker
point to the impact point on the outer surface of the test helmet.
S7.2.5 The contactable surface of the penetration test headform is
constructed of a metal or metallic alloy having a Brinell hardness
number no greater than 55, which will permit ready detection should
contact by the striker occur. The surface is refinished if necessary
before each penetration test blow to permit detection of contact by the
striker.
S7.2.6 The weight of the penetration striker is 6 pounds, 10
ounces (3 kg).
S7.2.7 The point of the striker has an included angle of
60 deg., a cone height of 1.5 inches (3.8 cm), a tip radius of 0.02 inch
(standard 0.5 millimeter radius) and a minimum hardness of 60 Rockwell,
C-scale.
S7.2.8 The rigid mount for the penetration test headform is as
described in S7.1.11.
S7.3 Retention system test.
S7.3.1 The retention
system test is conducted by applying a static tensile load to the
retention assembly of a complete helmet, which is mounted, as described
in S6.3, on a stationary test headform as shown in Figure 4, and by
measuring the movement of the adjustable portion of the retention system
test device under tension.
S7.3.2 The retention system test device
consists of both an adjustable loading mechanism by which a static
tensile load is applied to the helmet retention assembly and a means for
holding the test headform and helmet stationary. The retention assembly
is fastened around two freely moving rollers, both of which have a 0.5
inch (1.3 cm) diameter and a 3-inch (7.6 cm) center-to-center separation, and which are
mounted on the adjustable portion of the tensile loading device (Figure
4). The helmet is fixed on the test headform as necessary to ensure that
it does not move during the application of the test loads to the
retention assembly.
S7.3.3 A 50-pound (22.7 kg) preliminary test load is
applied to the retention assembly, normal to the basic plane of the test headform and symmetrical with respect to the center of the retention
assembly for 30 seconds, and the maximum distance from the extremity of
the adjustable portion of the retention system test device to the apex
of the helmet is measured.
S7.3.4 An additional 250-pound (113.4 kg)
test load is applied to the retention assembly, in the same manner and
at the same location as described in S7.3.3, for 120 seconds, and the
maximum distance from the extremity of the adjustable portion of the
retention system test device to the apex of the helmet is measured.
Appendix to Sec. 571.218
(wBW Note: Graphics have been omitted.)
Table 1--Weights for Impact Attenuation
Test Drop Assembly; Test headform size Weight \1\--1b(kg); Small - 7.8 (3.5 kg).;
Medium - 11.0 (5.0 kg).; Large - 13.4 (6.1 kg).
\1\ Combined weight of instrumented test headform and supporting
assembly for drop test.
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[38 FR 22391, Aug. 20, 1973, as amended
at 39 FR 3554, Jan. 28, 1974; 45 FR 15181, Mar. 10, 1980; 53 FR 11288,
Apr. 6, 1988; 53 FR 12529, Apr. 15, 1988]
