Given that so many consumers slap on sunscreen as a precursor to diving into the ocean, or a hotel pool on holiday, water resistance is a highly in-demand attribute when it comes to sun protection.
But, until recently, there was no universal immersion procedure to ascertain water resistance.
Both the US Food and Drug Agency (FDA) and Cosmetics Europe have their own methods, but these subtly differ and there is little way of telling whether these differences have an effect on the results or not.
Therefore, the testing of sunscreen water resistance and its calculation were both ripe candidates for standardised procedures under the International Organization for Standardization (ISO).
ISO 16217, which specifies a procedure of water immersion for the in vivo determination of the water resistance of sunscreen products, and ISO 18861, specifying a procedure for evaluating the water resistance retention percentage, were both published this year.
Dr Marc Pissavini, Research Director at Coty and convenor of ISO’s Working Group 7 (WG7: Sun Protection Test Methods) tells Cosmetics Business that work on the procedure for immersion, ISO 16217, began in Paris back in 2015, with work on the second standard, ISO 18861, the calculation of the percentage of water resistance, commencing roughly a year later.