Safety Glasses: Understanding Effectiveness and Limitations

Proper use of safety glasses do prevent most eye injuries, but they are not 100% effective. Because all materials, including plastic, have a yield point, it is possible for an object moving at a sufficiently high speed to penetrate the glasses. Even if a pair of safety glasses passes rigorous safety testing, there are limits to what safety gear can withstand.

The ANSI Z87.1-2003

• The American National Standards Institute establishes standards for safety glasses manufacturers to follow. Currently, adhering to the ANSI Z87.1-2003 standards is still voluntary; it's only mandatory to follow the ANSI Z87.1-1989 standards.

Basic Impact vs. High Impact

• The ANSI Z87.1-2003 differentiates between two levels of standards. In addition to passing all of the Basic Impact tests, high impact safety glasses must endure a high velocity test. If a pair of safety glasses do not pass the high impact standards, they must be labelled accordingly.

The High Velocity Test

• In order to pass the high velocity test, safety glasses must withstand impact from a steel ball with a 1/4" diameter travelling at 150 feet per second.

The Drop Ball Test

• To pass the the drop ball test, a pair of glasses must survive a steel ball with a 1" diameter dropped onto them from a vertical distance of 50".

Warning

• Check to make sure that a pair of safety glasses follow the ANSI Z87.1-2003 standards of safety. If you engage in riskier tasks, make sure that the manufacturer labelled your glasses or goggles as "high impact."