Cosmetics - Sun protection test methods - Water immersion procedure for determining water resistance (ISO 16217:2020)

This technical specification outlines a standardized test procedure designed to evaluate the water resistance of cosmetic sun protection products. The methodology focuses specifically on the immersion process, providing a controlled environment to simulate exposure to water during use. By following the defined steps, laboratories can consistently measure the retention of the product's protective efficacy after being subjected to immersion. This approach ensures that results are comparable across different testing facilities and product formulations. The protocol establishes clear requirements for sample preparation, the duration of immersion, and the subsequent assessment of sunscreen activity. It aligns with international frameworks to facilitate trade and ensure product safety information is reliable. The procedure addresses the practical challenges of assessing how well a product maintains its barrier function when in contact with water, which is a critical factor for consumer protection. Adherence to these guidelines allows manufacturers and regulators to verify product performance claims accurately without subjective interpretation.