Protective-corrective spectacles include three major components consisting of the frame, lenses and sideshields. A different manufacturer generally produces each component of the device. Individual components may be designed to perform different protective functions and may require various types and degrees of testing.
- Glass lenses shall be capable of resisting the impact of a one inch diameter steel ball dropped from a height of fifty (50) inches and shall not fracture as a result of the test. Impact resistance in glass can be achieved by subjecting each lens to heat treatment or chemical treatment and are considered basic protection.
- CR 39 hard resin plastic lens shall be capable of resisting the impact of a one (1) inch diameter steel ball dropped from a height of fifty (50) inches and shall not fracture as a result of the test. Prescription lenses are exempt from penetration testing requirements, as they are destructive in nature, and are considered basic protection.
- Polycarbonate lenses shall be capable of resisting the impact of a ¼ (.250) inch steel ball fired at 150 feet per second and shall not fracture as a result of the test procedure. Polycarbonate prescription lenses are rated high velocity impact resistant and are exempt from penetration testing, as it is destructive in nature.
REMOVABLE LENS MARKING
- Each prescription lens shall be permanently marked with the manufacturers monogram. High impact lens will carry a “+” after the monogram. In addition, if other than clear, each lens shall be marked with the shade designation such as 2.0 for green, V for photochromic or S for special purpose lens for other filter type lenses.
HIGH VELOCITY IMPACT TEST
- PURPOSE. This test in intended to ensure a level of protection from high velocity, low mass projectiles. The projectiles used for this test are .250 (1/4 in) diameter steel balls.
- TEST APPARATUS. The test apparatus shall consist of any device capable of propelling a steel ball reproducibly at 150 feet per second.
- The protective device shall be mounted on an Alderson 50th percentile male headform in the manner in which the device is usually worn.
- The head form shall be capable of being rotated about a vertical axis through each corneal vertex in 15 degree increments, from a first firing position 15 degrees to the nasal side of straight-ahead-viewing out to 90 degrees temporally.
- FRAME TEST. For the purpose of this test, frames shall be equipped with 2mm polycarbonate test lenses.
- For the High Velocity Impact test, no contact with an eye of the headform is permitted as a result of the impact.
- No parts or fragments shall be ejected from the frame that could contact an eye of the headform.
- Frames shall be capable of resisting impact from a 6.35mm (1/4 in) steel ball traveling at a velocity of 150 feet per second.
- MARKING. All major spectacle components except lenses shall bear a trademark identifying the manufacturer of that component and shall be marked “Z87” or “Z87-2 to indicate basic or high impact level of compliance.
- SIDESHIELDS. The new standard requires that all sideshields be High Velocity Impact Tested at two specific locations, each 10mm behind the corneal plane of the eye:
- 1st impact, 10mm posterior to the corneal plane and 10mm above.
- 2nd impact, 10mm posterior to the corneal plane and 10mm below.
- The testing is performed on a compliant basic of high velocity frame test platform.
- Acceptable results. No contact with an eye of the headform is permitted as a result of the impact.
- No parts for fragments shall be ejected from the sideshield, which could contact an eye of the headform.
MAINTENANCE AND CARE
- Eye protectors should be cleaned frequently with mild soap and water only.
- Cleaning agents containing alcohol and other chemicals can weaken polycarbonate resulting in premature failure.
- Inspect the complete protector for pits, scratches or crazing and replace when any of these conditions exist.
Patent No.5,748,278,6,393,609 B1 and others