Which type of light is most damaging to synthetic fiber slings?

• A. LED light
• B. Infrared light
• C. Ultraviolet light
• D. Neon light

Answer: (C)

Ultraviolet light is the most damaging because its high-energy photons cause photochemical degradation in the polymers that make up synthetic fiber slings. This process breaks chemical bonds in the fiber, leading to reduced tensile strength, embrittlement, and faster aging—even if there isn’t obvious surface damage. Over time, UV exposure can significantly shorten a sling’s service life and increase the risk of failure.

Infrared light mainly causes heat. While excessive heat can contribute to wear, it doesn’t induce the same direct chemical damage to the polymer as UV light. Visible-light sources, like LEDs, typically emit little to no harmful UV energy, and neon lights produce visible light without the high-energy photons that drive polymer degradation. So, UV light stands out as the primary threat to the integrity of synthetic fiber slings.