§ 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 helmets designed for use by motorcyclists and other motor vehicle users. The requirements of this standard apply to all helmets that can be placed on the size C headform using normal fitting procedures. Helmets that cannot be placed on the size C headform will not be covered by this standard until it is extended to those sizes by further amendment.

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.

"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 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 the Appendix.

"Reference headform" means a measuring device contoured to the dimensions of one of the four headforms described in the Appendix, with surface markings indicating the locations of the basic, midsagittal, and reference planes, and the centers of the external ear openings.

"Test headform” means a test device contoured to the dimensions of one of the four reference headforms described in the Appendix for all surface areas that contact the helmet, with surface markings indicating the locations of the basic, midsagittal, and reference planes.

"Retention system" means the complete assembly by which the helmet is retained in position on the head during use.

"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.

S5. Requirements. Each helmet shall meet the requirements of S5.1 through S5.3 when subjected to any conditioning procedure specified in S6.3, and tested in accordance with S7.

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 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 S6.1.3. The helmet shall provide peripheral vision clearance of at least 105° to each side of the midsagittal plane, when the helmet is adjusted as specified in S6.2. 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 midsagittal and basic planes. The brow

opening of the helmet shall be at least 1 inch 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 0.19 inch.

S5.6 Labeling.

S5.6.1 Each helmet shall be permanently and legibly labeled, in a manner such that the label(s) can be easily read without removing padding or any other permanent part, with the following:

(1) Manufacturer's name or identification.

(2) Precise model designation. (3) Size.

(4) Month and year of manufacture. This may be spelled out (e.g., June 1974), or expressed in numerals (e.g., 6/74).

(5) 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 % inch high, centered laterally approximately 1 inches from the bottom edge of the posterior portion of the helmet.

(6) Instruction to the purchaser as follows:

"Shell and liner constructed of (identify type(s) of materials).

"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).

"Make no modifications. Fasten helmet securely. If helmet experiences a severe blow, return it to the manufacturer for inspection, or destroy and replace it." (On an attached tag, brochure, or other suitable means, any additional, relevant safety information should be supplied at the time of purchase.)

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 following procedures.

S6.1 Reference marking.

S6.1.1 Use a reference headform that is firmly seated with the basic and reference planes horizontal. Place the complete helmet to be tested on the reference headform of the largest size specified in the Appendix whose circumference is not greater than the internal circumference of the headband when adjusted to its largest setting, or if no headband is provided to the corresponding interior surface of the helmet.

S6.1.2 Apply a 10-pound static load normal to the helmet's apex. Center the helmet laterally and seat it firmly on the reference headform according to its helmet positioning index.

S6.1.3 Maintaining the load and position described in S6.1.2, draw a line (hereinafter referred to as "test line") on the outer surface of the helmet coinciding with portions of the intersection of that surface with the following planes, as shown in Figure 2:

(a) A plane 1 inch above and parallel to the reference plane in the anterior portion of the reference headform;

(b) A vertical transverse plane 2.5 inches behind the point on the anterior surface of the reference headform at the intersection of the midsagittal and reference planes;

(c) The reference plane of the reference headform;

(d) A vertical transverse plane 2.5 inches behind the center of the external ear opening in a side view; and

(e) A plane 1 inch below and parallel to the reference plane in the posterior portion of the reference headform.

S6.2 Helmet positioning. Prior to 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 prior to impact or to application of force during testing.

S6.2.1 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.

S6.3

Conditioning. Immediately prior to 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° F. and a relative humidity of 50 percent for 12 hours.

(b) Low temperature. Expose to a temperature of 14° F. for 12 hours.

(c) High temperature. Expose to a temperature of 122° F. for 12 hours.

(d) Water immersion. Immerse in water at a temperature of 77° F. for 12 hours.

If during testing, the time out of the conditioning environment for a test helmet exceeds 5 minutes, return the helmet to the conditioning environment for a minimum of 3 minutes for each minute out of the conditioning environment or 12 hours, whichever is less, prior to resumption of testing.

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 S6.2, when it is dropped in guided free fall upon fixed hemispherical and flat steel anvils.

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 S7.1.7 and S7.1.8. The impact sites are at any point on the area above the test line described in S6.1.3, and separated by a distance not less than one-sixth of the maximum circumference of the helmet.

S7.1.3 The guided free fall drop heights for the helmet and test headform combination onto the hemispherical anvil and flat anvil are 54.5 inches and 72 inches, respectively.

S7.1.4 Test headforms for impact attenuation testing are constructed of magnesium alloy (K-1A), and exhibit

no resonant frequencies below 3,000 Hz.

S7.1.5 Weight of the drop assembly, as specified in Table I, is the combined weight of the instrumented test headform and supporting assembly for the drop test. The weight of the supporting assembly does not exceed 20% of the weight of the drop assembly. The center of gravity of the combined test headform and supporting assembly lies within a cone with its axis vertical and forming a 10° included angle with the vertex at the point of impact.

S7.1.6 The acceleration transducer is mounted at the center of gravity of the combined test headform and supporting assembly with the sensitive axis aligned to within 5° of vertical when the test headform is in the impact position. The acceleration data channel complies with SAE Recommended Practice J211 requirements for channel class 1,000.

S7.1.7 The flat anvil is constructed of steel with a 5-inch minimum diameter impact face, and the hemispherical anvil is constructed of steel with a 1.9inch radius impact face.

S7.1.8 The rigid mount for both of the anvils consists of a solid mass of at least 300 pounds, the outer surface of which consists of a steel plate with minimum thickness of 1 inch and minimum surface area of 1 ft2.

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 S6.2, at any point above the test line, described in S6.1.3, except on a fastener or other rigid projection.

S7.2.2 Two penetration blows are applied at least 3 inches apart, and at least 3 inches from the centers of any impacts applied during the impact attenuation test.

S7.2.3 The height of the guided free fall is 118.1 inches, as measured from the striker point to the impact point on the outer surface of the test helmet.

S7.2.4 The contractable surfaces of the penetration test headforms are constructed of a metal or metallic alloy a having Brinell hardness

number no greater than 55, which will readily permit detection should contact by the striker occur. The surface is refinished if necessary prior to each penetration test blow to permit detection of contact by the striker.

S7.2.5 The weight of the penetration striker is 6 pounds, 10 ounces.

S7.2.6 The point of the striker has an included angle of 60°, a cone height of 1.5 inches, a tip radius of 0.019 inch (standard 0.5 millimeter radius) and a minimum hardness of 60 Rockwell, Cscale.

S7.2.7 The rigid mount for the penetration test headform is as described in S7.1.8

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 S6.2, 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 diameter and a 3-inch 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 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 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.