S6. Test conditions. latched (where latches are provided) S6.1 The vehicle is on a flat, hori- in the condition intended for normal zontal surface. S6.2 The inside of the vehicle and the outside environment are kept at any temperature from 70° to 85° Fahrenheit for 4 hours immediately preceding the tests, and during the tests. S6.3 For the window retention test, windows are installed, closed, and bus operation. S6.4 For the emergency exit release and extension tests, windows are installed as in S6.3, seats, armrests, and interior objects near the windows are installed as for normal use, and seats are in the upright position. 23 INCH RADIUS 23 INCH RADIUS 2 INCHES 2 INCHES ADJACENT SEAT 23 INCH RADIUS 23 INCH RADIUS POINT OF 2 INCHES 5 INCHES FLOOR BENEATH EMERGENCY EXIT VIEW PARALLEL TO SEAT BACK CLEARANCE AREA AROUND SEAT BACK, ARM RESTS, 23 INCHES 71 INCHES 23 INCH RADIUS 23 INCH RADIUS 2 INCHES 23 INCH RADIUS 23 INCH RADIUS 2 INCHES 2 INCHES 5 INCHES POSSIBLE ARMREST ADJACENT SEAT FLOOR BENEATH EMERGENCY EXIT VIEW PERPENDICULAR TO SEAT BACK ACCESS REGION IS THE SPATIAL VOLUME CREATED FIGURE 1 LOW-FORCE ACCESS REGION FOR EMERGENCY EXITS HAVING ADJACENT SEATS REGION A REGION B POINT OF 2 INCHES ADJACENT SEAT 5 INCHES FLOOR BENEATH EMERGENCY EXIT VIEW PARALLEL TO SEAT BACK *CLEARANCE AREA AROUND SEAT BACK, ARM RESTS, AND OTHER OBSTRUCTIONS 23 INCHES REGION A REGION B 2 INCHES 2 INCHES 52 INCHES 2 INCHES POSSIBLE 5 INCHES ADJACENT SEAT FLOOR BENEATH EMERGENCY EXIT VIEW PERPENDICULAR TO SEAT BACK FIGURE 2 HIGH-FORCE ACCESS REGIONS FOR EMERGENCY EXITS HAVING ADJACENT SEATS 23 INCHES 23 RADIUS 23" RADIUS ACCESS REGION FOR LOW FORCES ACCESS REGION FOR HIGH FORCES INSIDE FLOOR INSIDE WALL 71 INCHES 52 INCHES 24 INCHES 2 INCHES 52 INCHES 71 INCHES 3D. REAR EMERGENCY EXIT WITHOUT REAR OBSTRUCTION FIGURE 3 LOW AND HIGH-FORCE ACCESS REGIONS FOR EMERGENCY EXITS WITHOUT ADJACENT SEATS [37 FR 9395, May 10, 1972, as amended at 37 FR 18035, Sept. 6, 1972; 38 FR 6070, Mar. 6, 1973; 38 FR7562, Mar. 28, 1973; 39 FR 15274, May 2, 1974;; 40 FR 48512, Oct. 16, 1975; 41 FR 3872, Jan. 27, 1976; 41 FR 22357, June 3, 1976; 41 FR 24592, June 17, 1976; 41 FR 36027, Aug. 26. 1976] § 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 helmets that fit headform size C, manufactured on or after March 1, 1974. Helmets that do not fit headform size C 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 |