This part of ISO 6270 specifies a method for determining the resistance of paint films, paints systems and related products to conditions of high humidity in accordance with the requirements of coating or product specifications. The method is applicable to coatings both on porous substrates such as wood, plaster and plasterboard and on non-porous substrates such as metal. It provides an indication of the performance likely to be obtained under severe conditions of exposure where continuous condensation occurs on the surface. The procedure may reveal failures of the coating (including blistering, staining, softening, wrinkling and embrittlement) and deterioration of the substrate.