What's the difference in SPF, UPF and why should you care?
I am sure that you have seen a lot of clothing and skin care brands with SPF and UPF labeling. Perhaps you already know that both are indications of protection from harmful rays of the sun. But have you ever wondered what exactly these terms mean?
Read on to find out more..
According to Skin Cancer Foundation, Sun Protection factor (SPF) is based on the time it takes for UV-exposed skin to redden. If used correctly, an SPF 15 sunscreen may protect your skin 15 times longer. It is important to use a broad-spectrum sunscreen of SPF 15+ and make sure to reapply every 2 hours when you are outdoors for proper sun protection.
Ultraviolet Protection Factor (UPF) indicates how much UV radiation (UVA and UVB) a fabric allows to reach your skin. For example, a UPF 50 fabric blocks 98% of the sun’s rays and allows 2% (1/50th) to penetrate, thus reducing your risk of exposure significantly. A UPF of 30 - 49 offers very good protection, while UPF 50+ rates as excellent.
UVB rays are the main cause of sun burn and non-melanoma skin cancers like squamous cell carcinoma. UVA rays penetrate our skin more deeply and are associated with cancer and skin aging.
How does SPF differ from UPF?
SPF measures only UVB while UPF measures both UVA and UVB rays.
SPF is based on the time it takes for UV exposed skin to redden. If your sun screen is SPF 15, it will protect your skin 15 times longer from burning. UPF measures the amount of UV radiation that penetrates a fabric and reaches your skin.
Why should you care about SPF and UPF differences and their values?
Knowing the exact difference between SPF and UPF is not an issue of vital importance as long as you find a sun screen that protects your skin and clothes with sun protection qualities. But it is always good to know what you are buying as a consumer. The values can be misleading and give you a false sense of security unless you really know what they actually mean.
Sometimes people get misled by the SPF factor. The SPF value is an unreliable measure of effectiveness of a sunscreen. A good product must provide broad spectrum protection against both UVA and UVB. The SPF value only reflects how well you are protected from UVB rays.
Does a very high SPF offer the best protection? Well, it is far from the truth. The sun protection of SPF 100 and SPF 50 sunscreen products are 99% and 98% respectively. Which means the extra protection is just 1%, which is negligible. Using a higher SPF can make you overconfident about sun protection which results in over exposure.
If you use a product with high SPF, make sure it is used properly. Improper usage will expose you to harmful UV radiation more than a person who uses a product with lower SPF value properly. Correct use of sun screen with SPF 30-50 will give you adequate protection even if you are very sensitive to sun burn.
Sun protective clothing is a safe and simple way to protect yourself from the sun. The Skin Cancer Foundation grants a seal of recommendation to a variety of products that meet the criteria for safe and effective sun protection. A fabric must have at least UPF of 30 to get this seal.
Now that you know the exact meanings, the differences between SPF and UPF and the importance of knowing the values, it will be easier for you to choose the best products to keep yourself safe and protected from the harmful UV rays.