How to take care of your hard hat
A general inspection should be done during assembly and before each use of the suspension and the shell. During the inspection you should look for cracks, nicks, dents, gouges, brittleness, fading, dullness of color or any damage caused by impact, penetration, abrasion or rough treatment. It the shell has any of these conditions it should be removed from service and replaced immediately.
UV light is a hard hats worst enemy and over time can cause deterioration due to the exposure of UV light. This is why it is never wise to store your helmet in the back of a truck, on the dash board or anywhere where it is going to be over exposed to UV light.
Field Testing for Degraded Shells
A simple field test can be performed to determine possible degradation of polyethylene shells: Compress the shell inward from the sides about 1 inch with both hands, and then release the pressure without dropping the shell. The shell should quickly return to its original shape, exhibiting elasticity. There should be no residual deformation. Compare the elasticity of the sample with that if the user environment is known to include higher exposure to temperature extremes, sunlight, or chemicals, hard hats should be replaced routinely after two years of use of a new shell. If the sample does not exhibit elasticity similar to that of a new shell, or if it cracks because of brittleness, it should be replaced immediately.