Sun Protective Clothing

Ultraviolet Protection Factor (UPF) ratings is for fabric what SPF (Sun Protection Factor) ratings is for sunscreen - it indicates what fraction of the sun’s UV rays can penetrate a given fabric. A UPF rating of 25, for example, means the material allows 1/25 (4 percent) of UV radiation in, and a UPF 50 garment lets in 1/50 (2 percent).

Frustrations with sunscreen - the need for frequent application, the inevitable greasy feeling, and the potential risk to ocean life, along with an increased awareness of the hazards of extended sun exposure - have helped expand the UPF-clothing industry to include appealing, everyday styles.

You can now find UPF clothing from dozens of companies and in thousands of designs, all using tighter weaves or treated fabrics (or often, both) to better block the sun’s rays. Some brands (such as Coolibar, Mott50, and UV Skinz) specialize exclusively UPF clothing, while other labels (like Lilly Pulitzer, Uniqlo, Athleta, MEC) now offer UPF pieces.

Some UV radiation passes directly to the skin through micro-spaces between the fibers of most fabrics, the fibers absorb some, and some are scattered off by reflection. Labs use protocols to measure how much of this radiation gets through specific fabrics. Moisture can also affect a fabric’s UPF: Dry garments are generally more protective than those same pieces once they are wet.

A lightweight, 100 percent cotton white T-shirt has a UPF of only around 5. A garment isn’t considered sun protective if it has a UPF rating lower than 15. To earn the Skin Cancer Foundation’s Seal of Recommendation, a voluntary recognition, it must have a rating of at least 30 from one of those independent bodies.

UPF 30 or higher offers sufficient protection, but “50+” provides the best available. (Likewise, although any sunscreen technically offers some skin protection, the American Academy of Dermatologists recommends SPF 30 and above.) A UPF value above 50 doesn’t provide significantly improved protection, so instead of reporting UPF 100, or UPF 500, which sounds impressive but means nothing, most brands say 50+.

If you’re looking to dress with sun safety in mind, here are a few general qualities to consider:

• The tightness of the fabric’s weave: A tightly-woven piece with smaller holes between the thread, like denim, will offer more protection than one with an open weave, like a crocheted shawl,

• Color and thickness of the fabric: Thicker, darker materials are more protective than thin, light ones. A bleached cotton offers little protection, whereas a black corduroy would block more UV radiation. A lightweight, 100 percent cotton white T-shirt has a UPF of around 5.

• Material composition: Synthetic materials are better at protecting against UV radiation than natural ones. Generally speaking, polyesters and rayons outperform wool and cotton.

• Material fit: If a garment stretches against your skin, there will be more significant gaps in the fibers, and more light (and radiation) will reach you. Looser fits offer more protection (and more breathability, too).

• Coverage: Of course, whether your garment is UPF-rated or not, the more skin it covers, the more skin it can protect - think longer sleeves, wider brims etc.