NFT 30-077 Test Standard specifies a method for determining the resistance of a paint film, paint systems and related products to conditions of high humidity. The method is applicable to coatings both on porous substrates, such as wood, plaster and plasterboard, as well as on non-porous substrates, such as metal. It gives an indication of the performance likely to be obtained under severe exposure conditions and when continuous condensation occurs on the surface. The procedure may show coating defects (including blistering, staining, softening, crimping, embrittlement) and deterioration of the substrate. It also determines Ash Content.