What minimum thickness must ANSI safety lenses have?

The minimum thickness requirement for ANSI safety lenses is established to ensure adequate impact resistance for the lenses in safety eyewear. A thickness of 3.0 mm is deemed necessary because it allows the lenses to withstand the kind of force that can occur in environments where safety glasses are needed, such as industrial settings. This thickness helps to prevent shattering or splintering, thereby protecting the eyes from potential hazards such as flying debris or chemical splashes.

The standard set by ANSI (American National Standards Institute) takes into account various factors, including the types of materials used for the lenses and the conditions under which they will be used. Lenses that meet this thickness requirement can provide improved protection, ensuring that they do not easily break under pressure or impact.

While thinner lenses might be suitable for regular eyewear, safety lenses must adhere to these more stringent criteria to qualify as adequate protective eyewear. Therefore, 3.0 mm stands out as the correct answer, emphasizing safety through its robust impact resistance.