GB/T 30648.3-2015 "Paints and varnishes - Determination of resistance to liquids - Part 3: Method using an absorbent medium" specifies a test method for determining the resistance of single or multi-layer coatings to the action of liquid or paste test media using an absorbent medium, which can assess the degree of damage caused by the test media to the coating surface and substrate. The test requires equipment such as a heating chamber with forced ventilation, 40 mm diameter watch glasses, 60 mm Petri dishes, and special filter paper or cotton balls. After conditioning the test panels under standard environmental conditions, the absorbent medium saturated with the test liquid is placed on the test panel and covered for protection. After exposure for an agreed-upon time, the panels are cleaned, and changes in the coating are evaluated against standards. This standard provides a normative basis for testing the liquid resistance of coatings.