ISO 8502-4-2017 Preparation of steel substrates before painting and related products - Tests for assessment of surface cleanliness, Part 4: Guidelines for estimating the probability of condensation before painting provides guidance for assessing the probability of condensation on surfaces to be painted. This standard is applicable to the need for surface cleanliness assessment of steel structures in industrial environments. It highlights the potential impact of condensate films on coating adhesion and performance, particularly under high Humidity conditions. The standard helps users to determine suitability for painting operations by providing test methods suitable for field conditions, thus improving the durability and performance of coatings.