SPF of Clothing

Last Modified: June 9, 2009

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Question

Dear OncoLink "Ask The Experts,"

I have seen clothing that has SPF on the label. Is this effective?

Answer

Carolyn Vachani RN, MSN, AOCN, OncoLink's Nurse Educator, responds:

It’s good that you are thinking outside the sunscreen box for ways to reduce sun exposure. Most people do not use nearly enough sunscreen or reapply often enough to get the labeled benefit of that sunscreen. Clothing, hats and sunglasses are important pieces to the sun protection puzzle.

Studies on the sun protection offered by summer clothing found that almost half provided less than the equivalent of an SPF of 30. A typical white t-shirt has a sun protection factor around 7, and this drops to about 3 when it is wet. Darker colored clothing and those garments with tighter weave provide more protection. The more worn or stretched out a garment becomes, the less SPF it offers. All of these variables make it difficult for people to assess the protection of clothing, so a system was developed to test and certify the sun protection of fabrics.

Ultraviolet Protection Factor (UPF, UVPF) is the clothing equivalent of SPF for sunscreen. The standard UPF ratings were developed in Australia, where melanoma is an enormous health concern, by ARPNSA (formerly the Australian Radiation Laboratory). The U.S. FDA or EPA does not regulate clothing ratings, but two organizations have standards that manufacturers can voluntarily utilize. Those standards are the American Association of Textile Chemists and Colorists Test Method 183 and American Society for Testing and Materials (ASTM) D6544. The latter tests clothing after two years of wear.

Clothing is given a rating from 15 to 50+, with higher ratings referring to more protection. A rating of 20 means the garment allows 1/20th of the UV rays to pass through it. A rating of 30 means the garment allows 1/30th of the UV rays to pass through it and so forth. The ARPNSA standard rates clothing according to the percent of UV rays blocked and assign the ratings to a protection category based on this (good, very good, excellent) (table below). UPF of 50 is the highest recognized, so any garment testing above this is labeled as 50+. If a garment is made of different fabrics or different colors, the rating is that of the lowest UPF of all the fabrics/colors in the garment.

UPF Ratings and Protection Categories

UPF Rating

Protection Category

% UV rays blocked

15, 20

Good

93.3-95.9

25, 30, 35

Very Good

96-97.4

40, 45, 50, 50+

Excellent

97.5 or higher

Clothing that has been tested by these standards will display it’s rating on a hangtag. These products are often quite expensive and may not be necessary for everyone or every situation. Those with particularly sensitive skin and children and babies should consider protective clothing. When you cannot avoid the sun in peak hours or are in for high sun exposure, such as the beach, these garments can be a helpful piece of the puzzle.

You may also see products that can be added to the laundry to boost UV protection of clothing. Many laundry detergents contain brightening agents that can actually improve the protection over multiple washings, but this is not reliable, as some fabrics will lose protection with wear and laundering. Rit Sun Guard is a product you add to your laundry to add UV blocking equivalent to an SPF of 30. It reportedly works in one wash and only needs to be re-applied every 20 washes.



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