Levels of protection
Safety glasses can vary in the levels of protection they provide. They may give the eyes the following protection:
From flying debris, objects and sparks. Most objects that strike the eye are smaller than a pin head. However, injury may also occur from tree limbs, ropes, chains or even tools which were pulled into the eye while using them. Safety glasses should be worn while performing tasks such as chipping, drilling, grinding, polishing, buffing, riveting, shearing, hammering,
sawing, planning, and lathe work to keep objects/particles from flying into the eyes.
From visible light or radiation. They should be used whenever a person is in a hazardous area such as a machine room or construction site when welding, brazing, furnace work, metal pouring. From contact with chemicals, such as in a lab or hazardous material area. This can occur while handling acid or alkali or chemical spraying. From glare or stray light which may occur when working in bright sunlight, or reflected welding flash and photographic copying.
To be effective, the eyewear must be of the appropriate type for the hazard encountered and properly fitted. It is estimated that 90% of eye injuries can be prevented through the use of proper protective eyewear.
The National Institute for Occupational Safety and Health suggests using ANSI Z87.1 certified industrial eye protection with Z87 on the frame/lens. Eye protective devices should allow for air to circulate between the eye and the lens.