ISO 24444:2019 pdf download.Cosmetics — Sun protection test methods — In vivo determination of the sun protection factor (SPF)
1 Scope
This document specifies a method for the in vivo determination of the sun protection factor (SPF) of sunscreen products. It is applicable to products that contain any component able to absorb, reflect or scatter ultraviolet (UV) rays and which are intended to be placed in contact with human skin.
This document provides a basis for the evaluation of sunscreen products for the protection of human skin against erythema induced by solar ultraviolet rays.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1 ultraviolet radiation
UVR
electromagnetic radiation in the range of 290 nm to 400 nm
3.1.1 ultraviolet B
UVB
electromagnetic radiation in the range of 290 nm to 320 nm
3.1.2 ultraviolet A
UVA
electromagnetic radiation in the range of 320 nm to 400 nm
Note 1 to entry: UVA II = 320 nm to 340 nm; UVA I = 340 nm to 400 nm.
4 General principle
The SPF test method is a laboratory method that utilizes a xenon arc lamp solar simulator (or equivalent) of defined and known output to determine the protection provided by sunscreen products on human skin against erythema induced by solar ultraviolet rays. The test shall be restricted to the area of the back of selected human subjects. A section of each subject’s skin is exposed to ultraviolet light without any protection while another (different) section is exposed after application of the sunscreen product under test. One further section is exposed after application of an SPF reference sunscreen formulation, which is used for validation of the procedure. To determine the sun protection factor, incremental series of delayed erythemal responses are induced on a number of small sub-sites on the skin. These responses are visually assessed for presence of erythema 16 h to 24 h after UV radiation, by the judgment of a trained and competent evaluator. The individual minimal erythemal dose for unprotected skin (MED iu ) and the individual MED obtained after application of a sunscreen product (MED ip ) shall be determined on the same subject on the same day. An individual sun protection factor (SPF i ) for each subject tested is calculated as the ratio of individual MED on product protected skin divided by the individual MED on unprotected skin, as in the formula given in 3.5. The sun protection factor for the product (SPF) is the arithmetic mean of all valid SPF i results from each subject in the test expressed to one decimal place.
ISO 24444:2019 pdf download
