What is that truly separates safety glasses from standard glasses? After all, they’re both available with either prescription or non-prescription lenses, both with durable plastic or plastic lenses, and both in a wraparound style that protects the eyes and the side of the head. So what’s the real difference?
What Are the Correct Markings for Safety Glasses?
The difference boils down to materials used. Safety glasses usually feature a sturdier frame than standard glasses. If it’s a wire frame, it’s usually the type that gives under pressure and features side shield so objects can’t penetrate peripherally. If it’s plastic, the frame is typically tested to be impact resistant and not easily broken. And lenses in safety glasses tend to made of polycarbonate – the same plastic used to form jet plane cockpits.
You can tell if your glasses are officially safety rated by the markings they carry. The American National Standards Institute, or ANSI, has developed standards to insure that safety frames comply and are made of the proper materials to insure impact resistance. The most recent update to the ANSI standard that applies to safety eyewear is the ANSI Z87.1-2010 standard, which supersedes the previous designation, ANSI Z87.1-2003. Depending on when your frames were produced, they can be marked for either standard…but must be stamped with one of the ANSI designations, otherwise they are not safety glasses.
The ANSI Z87.1-2010 standard also stipulates that impact resistance must be identified. Safety glasses that are designed for impact resistance are made of the appropriate materials and must carry the manufacturer’s standard markings followed by a “plus” sign. If ANSI Z87.1-2010 glasses do not feature a “plus” sign, they are not impact rated. This does not mean they aren’t safety glasses – they’ll still protect from dust, wind, chemical splashes, and light debris entry – but they do not protect against projectiles moving at a high rate of speed.
Tinted safety glasses also feature special designations to identify them, as follows:
- “L” + a number – the Visible Light Filter rating
- “R” + a number – the Infrared Filter rating
- “V” – photochromic (or transition) lens designation
- “S” – special purpose lens designation
- “U” + a number – the Ultraviolet light scale rating
- “W” + a number – a welding designation, including the lens shade number
All ratings must be permanently stamped onto the lenses. It should be in the upper corner of a prescription lens and the upper middle edge of a non-prescription lens.
A little knowledge and diligence can go a long way in protecting your eyesight under dangerous conditions. Be sure your next pair of safety glasses is up to the task by checking the markings.