The shell of the helmet shall be of non-metallic materials conforming to the test requirements.

The protective padding shall be of expanded polyurethane foam, polyethylene or any other material having similar properties.

The comfort padding shall be of expanded polyurethane foam, polyethylene or any other suitable material having similar properties.

The retention system material for chin-strap and headband shall be sweat-resistant, non-irritant and shall not be known to cause skin disease.

The characteristics of the materials used in the manufacture of helmets shall be known not to undergo appreciable alteration under the influence of aging, or of other circumstances.

The strap shall not be less than 2Omm wide. The device to open the retention system shall not be capable of opening other than as a result of a deliberation act.

The helmet conditioned by solvents, ambient, ultra violet, heat and cold shall be tested for impact absorption.

The helmet shall be tested for their sound attenuation properties by the method given.

The sound transmission loss shall be not more than lOdB over the frequency range 250 to 2000Hz.

Impact absorption capacity is determined by recording against time acceleration imparted to a headform fitted with the helmet, when dropped in guided free fall at a specified impact velocity upon a fixed steel anvil.

The protective helmet shall be placed, with an initial load of 10 N, on a headform oriented in such a way that the plane tangential to the shell at the point selected for the test is substantially horizontal.

A metal punch with a conical head rounded at the top shall be placed vertically to touch the shell at the point selected and held in position by a ring. A metal drophammer shall fall on the top of the punch, and the depth to which the point penetrates into the shell shall be measured by means of an inertia-free device, such as a photoelectric device, indicating the minimum vertical distance reached, in this test between the head of the punch and the headform.