"ANSI Z89.1-1986 separates protective helmets into different types and classes.
The standard identifies Type 1 and Type 2 helmets. Type 1 helmets incorporate a full brim (the brim fully encircles the dome of the hat); Type 2 helmets have no encircling brim, but may include a short bill on the front (similar to a baseball cap).
In terms of electrical performance, ANSI Z89.1-1986 recognizes three classes:
Class A Helmets are intended to reduce the force of impact of falling objects and to reduce the danger of contact with exposed low-voltage electrical conductors. For certification, sample shells are proof-tested at 2,200 volts of electrical charge.
Class B Helmets are intended to reduce the force of impact of falling objects and to reduce the danger of contact with exposed high-voltage electrical conductors. Sample shells are proof-tested at 20,000 volts.
Class C Helmets are intended to reduce the force of impact of falling objects, but offer no electrical protection.
Note: The voltages stated in Classes A and B are not intended to be an indication of the voltage at which the headgear protects the wearer.
In addition to electrical protection, hard hats are also tested for impact and penetration resistance from blows to the top of the head, flammability resistance, and water absorption. The rigorous testing requirements are described in detail within the standard.
Every hard hat conforming to the requirements of ANSI Z89.1-1986 must be appropriately marked to verify its compliance. The following information must be marked inside the hat:
•The manufacturer's name
•The legend, "ANSI Z89.1-1986"
•The class designation (A, B or C)"