Hard hats are usually classified on the basis of the impact they can handle without damage, as well as their electrical performance requirements. This classification is also known as the American National Standard Institute (ANSI) Z89.1 Standards for Industrial Head Protection. All hard hats to be used in industry are manufactured in accordance with this standard. Each hat must carry an ANSI certification label on the inside of its shell. The label must clearly identify the type and class of the hat. If the label is missing, the hat should be replaced with another hat that has it.
Impact Type I
Impact Type I hard hats are designed to reduce the force of impact resulting from a force directly on top of the head. This type is the most commonly used hard hat. These hard hats diminish the collision impact of falling objects.
Impact Type II
Impact Type II hard hats are designed to decrease the force of impact resulting from a force that is received off center or on the top of the head. This type of hard hat is typically lined on the inside with thick high density foam or shock absorbing material.
Electrical Class G
An Electrical Class G hard hat decreases the risk of contact exposure to low voltage conductors. The hat is proof tested at 2,200 volts in order to pass the ANSI certification. Class G hard hats were formerly known as Class A.
Electrical Class E
Class E hard hats are designed to reduce the danger of exposure to high voltage conductors and electricity sources. Hats falling under this category are tested at 20,000 volts for ANSI certification. Class E hard hats used to be known as Class B hard hats.
Electrical Class C
Electrical Class C hard hats protect the wearer from falling objects but do not provide protection against contact with electrical conductors and are not electrically insulated. Their name has not been changed from the old standard.
The voltages stated in Classes G and E are not the indications of the voltage at which the hard hats will protect the wearer. Hard hats are sometimes tested for water absorption and flammability resistance. Any protective hard hat claiming compliance with ANSI requirements must be marked with its manufacturer's name, the code "ANSI Z89.1-1986" and the class of the hat (E, G or C).