Which of the following is NOT a properly matched marking according to ANSI standards for protective eyewear?

• A. "W" shade number -> welding
• B. "U" scale number -> UV filters
• C. "R" scale number -> Nuclear Radiation filters
• D. "L" number -> Visible filter

Answer: (C)

ANSI protective eyewear markings use letters to quickly show what kind of protection the lens provides. Each letter points to a specific type of filtration: W indicates welding shade protection, meaning the lens is designed to be used for welding and carries a shade appropriate for arc exposure; U signals ultraviolet protection, blocking UV radiation; R denotes infrared radiation protection, indicating the lens filters infrared radiation; and L refers to visible light filtration, showing how much visible light the lens allows through.

Knowing this, the pairing that isn’t correct is the one that assigns nuclear radiation filters to the R designation. R is meant for infrared, not nuclear radiation. Nuclear radiation protection isn’t specified by this R marking in ANSI labeling.

The other pairings line up with how the markings are used: a welding shade is correctly tied to the W designation, UV protection to the U designation, and a visible-light filtration characteristic to the L designation.