Are Safety Glasses 100% Effective?
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
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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
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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
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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
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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
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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."
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