Terms and Definitions
UPF is the abbreviation for Ultraviolet Protection Factor and an accompanying numbered system defines a fractional value of how much UV radiation can penetrate the product, for example a material of UPF 30 will allow a 1/30th of radiation to pass through it; the higher the UPF rating, the higher the protection level.
The abbreviation SPF (Sun Protection factor ) and accompanying number denotes the sun protection in terms of maximum exposure time provided by a product. For example, if say 10 minutes was the maximum unprotected exposure time for skin burn to occur. A product with an SPF 10 rating will increase the maximum exposure by a multiple of 10 to 100 minutes; a individual suffering skin burn after 1 hour of unprotected exposure, would be provided with 10 hours protection when wearing a SPF 10 garment.