Ultraviolet Protection Factor (UPF) in clothing measures how much ultraviolet radiation reaches your skin through your clothes. It can be especially important for outdoor workers.
The higher the UPF number, the better the protection. A shirt with a UPF rating of 50 allows 1/50th of the sun's rays to penetrate the fabric, according to Piedmont Healthcare. That means the material will block 98 percent of UV rays. As a contrast, a simple white T-shirt has a UPF rating of about 5.
High UPF rated clothing can absorb sun rays, prevent sunburns and skin damage. Good UPF protection ranges from 15 to 24. Excellent UV protection is rated from 40 to 50+.
Just as Sun Protection Factor (SPF) in sun lotion tells you how much skin protection you have, UPF in clothing tells how well the clothing protects the skin from UV rays. UV rays are a natural energy produced by the sun, but they are also found in tanning beds and certain lamps. They a form of electromagnetic radiation that are invisible. Protective clothing is designed to protect from two types of UV rays:
UVA: They penetrate deeper into the skin and contribute to tanning and premature aging. They may contribute to skin cancer development.
UVB: Primarily responsible for sunburn and skin cancer, and can also damage the eyes.
