SPF vs UPF: What’s the Difference?
Clothes are the most effective way to protect yourself from sunburn and skin cancer. There are two ways to protect yourself from the sun: wear sunscreen and wear clothes.
Most people know that sunscreen is rated with Sun Protection Factor (SPF), but they might not know that fabric is rated differently, with the Ultraviolet Protection Factor (UPF) standard.
What is UPF?
How much does a fabric protect you? Ultraviolet Protection Factor (UPF) measures how much UV radiation reaches your skin through a fabric.
For example, a fabric with UPF 50 blocks 98 percent of the sun’s rays and only allows two percent (1/50th) of UV rays to penetrate, significantly reducing your risk of exposure.
How is SPF Different Than UPF?
SPF is based on the time it takes for UV-exposed skin to redden; if you burn after 20 minutes, an SPF 15 sunscreen may protect your skin 15 times longer (if used correctly).
UPF measures the amount of UV radiation that can penetrate fabric and reach your skin.
UPF measures both UVB and UVA rays, while SPF measures only UVB. Ultraviolet A (UVA) has a longer wavelength and is associated with skin aging. Ultraviolet B (UVB) has a shorter wavelength and is associated with skin burning.
How is UPF Measured and Tested?
The UPF standard was created in 1998 by AATCC, based on original guidelines established in Australia in 1994. The testing standard for sun protective fabrics in the United States is the AATCC Test Method 183.
A spectrophotometer measures the amount of photons (the intensity of light) absorbed. UPF is generally tested using a spectrophotometer.
What Fabric Characteristics are Best for Sun Protection?
- Denim
- Canvas
- Wool
- Synthetic fibers such as polyester and nylon
Does Color Matter In UV Fabric Protection?
Darker colors absorb more UV than lighter colors like whites and pastels. This means the UV rays are less likely to reach your skin.
Bright colors such as red can also absorb UV rays. The more vivid the color, the greater the protection—a bright yellow shirt is more protective than a pale one.
SPF and UPF FAQ
Some of the most typical questions we are hear from customers about UPF are detailed below – let us know if you have other questions.
- Do clothing manufacturers have to rate products using UPF?
No, use of the UPF standard is voluntary so some sun protective fabric manufactures still use the SPF system.
- What is the Skin Cancer Foundation’s Seal of Recommendation for UPF?
A minimum of UPF of 30 is needed in order to qualify for the Skin Cancer Foundation’s Seal of Recommendation. A UPF 30 to UPF 49 is considered very good protection, UPF 50+ rates as excellent protection.