Measurement of UV protection afforded by sunscreens and clothing
| Measurement system
|
SPF (Sun protection factor)
|
UVA‐PF (UVA‐protection factor)
|
UPF (Ultraviolet protection factor)
|
| Definition
|
- The minimal erythema dose (MED) of UVB radiation causing erythema after applying 2 mg/cm2 of sunscreen to skin divided by the dose producing 1 MED on unprotected skin.
|
- The dose of UVA causing observable pigment darkening (minimal pigment dose [MPD]) after applying 2 mg/cm2 of sunscreen to skin divided by the dose producing 1 MPD on unprotected skin.
|
- The ability of fabrics to prevent the transmission of UV radiation by absorption and/or reflection and highly dependent on fabric type, porosity, color, weight, thickness, and other factors.
|
| Developed for
|
|
|
|
| Global acceptance
|
|
|
|
| UV wavelengths protected
|
|
|
|
| Examples
|
- SPF 2 protects against 50% of UVB
- SPF 8 protects against 88% of UVB
- SPF 15 protects against 93% of UVB
- SPF 30 protects against 97% of UVB
- SPF 50 protects against 98% of UVB
|
- UVA‐PF1 protects against 20–39% of UVA
- UVA‐PF2 protects against 40–69% of UVA
- UVA‐PF3 protects against 70–95% of UVA
- UVA‐PF4 protects against >95% of UVA
|
- UPF cotton 5–10
- UPF denim 1700
|
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sara Mohsin, M.D.[2]
References