ASTM D3273 – Standard Test Method for Resistance to Growth of Mold on the Surface of Interior Coatings in an Environmental Chamber
Description:
Significance and Use
3.1 An accelerated test for determining the resistance of interior coatings to mold growth is useful in estimating the performance of coatings designed for use in interior environments that promote mold growth and in evaluating compounds that may inhibit such growth and the aggregate levels for their use (see also Note 1).
3.2 This test method should preferably be used by persons who have had basic microbiological training.
Scope
1.1 This test method describes the use of an environmental chamber and operating conditions to evaluate the relative resistance of interior coatings to surface fungal growth in a severe interior environment during a 4-week period.
1.2 This test method can be used to evaluate the comparative resistance of interior coatings to accelerated mold growth. Performance at a certain rating does not imply any specific period of time for a fungal free coating. However, a better rated coating nearly always performs better in actual end use.
Note 1: This test method is intended for the accelerated evaluation of an interior coatings’ resistance to fungal defacement. Use of this test method for evaluating exterior coatings’ performance has not been validated, nor have the limitations for such use been determined. If this test method is to be used for the testing of an exterior coating system, a precautionary statement regarding interpretation of results as being outside of the scope of this test method must be included in the test report. Any accelerated weathering (leaching, weathering machine exposure, etc.) should be reported and should also bear reference to the fact that it is beyond the current scope of this test method.
1.3 Temperature and humidity must be effectively controlled within the relatively narrow limits specified in order for the chamber to function reproducibly during the short test period. Severity and rate of mold growth on a film is a function of the moisture content of both the film and the substrate. A relative humidity of >93 % at a temperature of 32.5 ± 1 °C (90 ± 2 °F ) is necessary to initiate and maintain mold growth and for test panels to develop rapidly and maintain an adequate moisture level to support mold growth.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
ASTM D3265