This International Standard is one of a series of standards dealing with the sampling and testing of coating materials, such as paints and varnishes, as well as coatings prepared from them. Natural weathering is used to determine the resistance of coatings or coating systems (denoted in the following text simply by coatings) to the sun's radiation and the atmosphere. Special atmospheric influences, e. g. industrial pollution, are not taken into account in this International Standard. This International Standard specifies the conditions which need to be taken into consideration in the selection of the type of natural weathering and the natural weathering procedure (direct weathering or weathering behind window glass).