This specification provides a description of a test method for protective headgear used in horse sports and horseback riding that will measure the ability of the headgear to reduce head acceleration when impacting objects of various shapes. Materials covered by this specification include the pair of appropriate size headform and helmet and the anvils for the impacts tests, which consist of the flat anvil and the equestrian hazard anvil. The helmet shall be conditioned in the following environments: ambient, low temperature, high temperature, and water immersion, and shall be impacted at each of four sites centered on or anywhere above the center of the impact line (two sites on the flat anvil and two sites on the equestrian hazard anvil). Dynamic loading and helmet stability tests shall be performed and shall conform to the requirements specified.