Abstract： AS/NZS 2604:2021 pdf download.Sunscreen products - Evaluation and classification. The amount of protection against sunburn offered by different sunscreens can be compared by simply looking at the ratio of their SPF numbers Therefore, for an...
AS/NZS 2604:2021 pdf download.Sunscreen products - Evaluation and classification.
The amount of protection against sunburn offered by different sunscreens can be compared by simply looking at the ratio of their
SPF numbers Therefore, for any exposure duration, an SPF 50 sunscreen has double the protection of an SPF 25 sunscreen.
Theory versus practice
Performing evaluations by exposing ordinary skin to natural sunlight is impractical. There are so many variable factors which
contribute significantly to the result that a single random determination is unlikely to coincide with the most probable result
obtained from a large number of determinations on different persons. Consequently, it is necessary, in a system intended to give a useful comparison of the potential protective efficiency cia wide range of sunscreen products, to specify certain constraints in
the method. Such constraints can be sensibly related to the processes operating when sunscreen products are used to prevent
sunburn. They may also be widely acceptable and readily realized in practice so that comparative evaluations can be made and,
preferably, accepted in different locations, both nationally and internationally.
Recommended：
