The ISO 23741-2021 standard specifies a procedure for the determination of the amount of water sprayed on a specimen during the spray cycle of a Xenon-arc aging test device. The standard provides a general method of how to accurately measure the amount of water sprayed on a specimen during the Xenon-arc aging test. This procedure helps to ensure the accuracy of the test conditions, resulting in an effective assessment of the tolerance of plastic materials exposed to environmental factors in actual use. The standard cites the ISO 4892 series literature, ensuring the conformity and Reliability of the test method. The standard is suitable for the plastics industry to optimize the aging performance testing process of materials.