This standard specifies the method for evaluating the durability of Paints and varnishes through exposure testing under natural climate conditions. It is suitable for the performance evaluation of coating materials in the natural environment after being affected by factors such as light, moisture, temperature changes, etc., including the requirements for sample preparation, exposure conditions, evaluation procedures and result reporting. The standard provides a scientific basis for analyzing the aging characteristics of coatings in the actual use environment. It has important reference value for the development, quality control and application of coatings. It is especially suitable for companies and research institutions that need to verify the performance of outdoor coatings and protective coatings. Standards are widely adopted in Europe and internationally, ensuring uniformity of test methods and comparability of results.