DIN EN ISO 11997-2:2013-12

Coatings of paints, varnishes and similar materials are exposed to cyclic wet and dry corrosion and UV exposure conditions using specified salt solutions in cabinets in order to simulate, in the laboratory, processes occurring in aggressive outdoor conditions. Generally, valid correlations between such outdoor weathering and laboratory testing cannot be expected because of the large number of factors influencing the breakdown process. Certain relationships can only be expected if the effect on the coating of the important parameters (for example nature of the pollutant, spectral distribution of the incident irradiance in the relevant photochemical region, temperature of the specimen, type and cycle of wetting and relative humidity) is known. In contrast to outdoor weathering, laboratory testing in a cabinet is performed with a reduced number of variables, which can be controlled and therefore the effects are more reproducible. The method described can give a means of checking that the quality of a paint or paint system is being maintained. The method is intended to provide a more realistic simulation of these factors than is found in traditional tests with continuous exposure to a static set of corrosive conditions. The method has been found to be useful in comparing the cyclic salt spray resistance of different coatings. It is most useful in providing relevant ratings for a series of coated panels exhibiting significant differences in cyclic salt spray and UV exposure resistance tested at the same time and to the same test cycle. The test cycle specified in this part of ISO 11997 has been found useful for air-drying industrial maintenance coatings on steel. Other cycles may be used as required. This part of DIN EN ISO 11997 is equivalent to ASTM D 5894-05, Standard Practice for Cyclic Salt Fog/UV exposure of Painted Metal, (Alternating Exposures in a Fog/Dry Cabinet and a UV/Condensation Cabinet). The committee responsible for this standard is NA 002-00-07 AA "Allgemeine Prüfverfahren für Beschichtungsstoffe und Beschichtungen" ("General test methods for coating materials and coatings") at DIN.