ANSI Z89.1-2003 is entitled, “Protective Requirements For Protective Headwear of Industrial Workers,” and is a revision to the previous standard ANSI Z89.1-1997. This standard written by the American National Standard Institute outlines the classes of hard hats based on the risk of danger to the person.
ANSI Z89.1-1997 was a revision of an earlier standard to include guidelines for hard hats in case of blows to the lateral side of the head, or blows to the top of the head.
There was only a small revision of ANSI Z89.1 from 1997 to 2003. The purpose of the 2003 revision was to state only the guidelines, making hard hats more effective to the user.