UPF is like the sun protective factor SPF used on sunscreen lotion bottles and fabrics today, in that both UPF and SPF measure sunburn protection. A lot of companies will bounce back and forth between SPF and UPF so let’s take a moment to clarify what exactly each of these acronyms means.
“SPF” stands for sun protection factor (or “sunburn protection factor”). The sun protection factor, SPF, is a gauge of how much time a person can be exposed to the sun before getting burned. If you are a person that typically can get sun burned in 15 minutes, an application of SPF 30+ sun block would allow you 450 minutes in the sun before getting burned, that is if you do not sweat or get wet.
“UPF” stands for UV Protection Factor and is the measurement of how much UV light it blocks. The amount of protection that any fabrication provides varies and is dependant upon the type of fabric, the weave or type of knit fabric. Historically, these fabrications have a denser weave or knit construction and are normally darker in color. A 1 over the UPF number demonstrates the maximum amount of UV rays coming through the fabric. A UPF 15 rating allows 1 out of every 15 UV rays through the fabric.
