Standard Practice for Testing Water Resistance of Coatings Using Single-Sided Controlled Condensation

Abstract

4.1 Water can cause degradation of coatings, so knowledge of how a coating resists water is helpful in predicting its service life. Failure in a condensation test may be caused by a number of factors including a deficiency in the coating itself, contamination of the substrate, or inadequate surface preparation. The test is therefore useful for evaluating coatings alone or complete coating systems. 4.2 Condensation tests of coatings are used for specification acceptance, quality control, and research and development of coatings and substrate treatments. These tests usually result in a pass or fail determination but the degree of failure also may be measured. A coating system is considered to pass if there is no evidence of water-related failure after a specified period of time. 4.3 Results obtained from the use of condensation tests in accordance with this practice should not be represented as being equivalent to a period of exposure to water in the natural environment, until the degree of quantitative correlation has been established for the coating or coating system. 4.3.1 This practice has been shown for some panels, to produce more severe results than completely enclosed (that is, two-sided) humidity tests, such as Practice D2247. 4.4 The test is usually conducted on metal, plastics, or wood specimens with the coating facing the inside of the chamber. However, it is possible to test the blister resistance of house coatings on wood specimens by mounting the uncoated wood surface facing the inside of the chamber. 4.5 This practice can be used for corrosion tests particularly if the specimens are periodically dried. While corrosion products will drain into the water bath, they are not carried into the vapor that condenses on the test specimens.