UPF is English referred to Ultraviolet Protection Factor, the UV protection factor.

According to national standards, UPF refers to "the ratio of the average effect of ultraviolet radiation calculated when the skin is unprotected to the average effect of ultraviolet radiation calculated when the skin has a fabric protection".

However, this definition is rather abstract. We can understand the physical meaning of UPF in this way. For example, if the UPF value is 50, it means that 1/50 of the UV light can penetrate the fabric.

The higher the UPF value, the better the UV protection. However, the national standard UPF value of the highest mark is 50 +, which is UPF> 50. Because UPF is greater than 50, the impact on the human body can be neglected.

AQSIQ promulgated the "evaluation of anti-UV textile properties" standard provides:

A. Only when the sample UPF value is greater than 30, and the UVA transmittance is less than 5%, can be called "UV products", these two conditions are indispensable. This is a constant a product is not "UV products" indicator.

B. UV products should be marked on the label with three aspects:

1, the national standard number: GB / T 188302

2, UPF value:

3,30+, or 50+