This specification covers performance requirements for helmets used by downhill mountain bicycle riders. Studies have shown higher risk to the head and face for this sport as compared to recreational street riding; hence, this specification requires greater impact protection and provides performance criteria for chin bars on full-face helmets, but does not require full-face helmets. Retention system tests shall be performed before impact testing. The helmet can be impacted anywhere on or above the test line with the curbstone anvil in any horizontal orientation. The ambient test helmet shall be subjected to the chin bar impact test.

1.1 This specification covers performance requirements for helmets used by downhill mountain bicycle riders. Studies have shown higher risk to the head and face for this sport as compared to recreational street riding; hence, this specification requires greater impact protection and provides performance criteria for chin bars on full-face helmets, but does not require full-face helmets. This specification recognizes the desirability of lightweight construction and ventilation; however, it is a performance specification and is not intended to restrict design.

1.2 All testing and requirements of this specification shall be in accordance with Test Methods F1446, except where noted herein.

1.3 Partial utilization of this standard is prohibited. Any statement of compliance with this specification must be a certification that the product meets all of the requirements of this specification in its entirety. A product that fails to meet any one of the requirements of this specification is considered to have failed this standard, and should not be sold with any indication that it meets parts of this standard.

1.4 Headgear designed to comply with this and other standards may proclaim uses as certified by the manufacturer.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 The following safety caveat applies to the chemical, mechanical, or physical, or a combination thereof, test methods described herein and is meant specifically for those performing the tests (in an effort to provide them with notice to take the appropriate precautions when conducting the tests): This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.