This standard is used to evaluate paint film defects on Coating surfaces due to fungal or algal growth and soil fouling accumulation. Fungal growth often causes film discoloration or deformation, affecting Appearance. The standard provides a visual comparison tool to identify and quantify the level of fungal or algal growth on paint film surfaces and to help distinguish between dirt and fungus. The standard emphasizes the difficulty of detection on different substrates, especially on dark substrates where the distinction between fungus and fouling is more complex. This method is mainly used for on-site visual rating and is suitable for coating of test plates or buildings.