Paints & varnishes – determination of resistance to cyclic corrosion conditions, Part 1: wet(salt fog)/dry/humidity.
This test method has been found to be useful for comparing the relative resistance to corrosion of paints, varnishes and similar materials, when exposed to a simulated aggressive outdoor environment, such as a marine environment. It is cyclic in nature, i.e.; test specimens are exposed to changing climates over time.
3 different test cycles are defined within this test method, which are referred to as Cycle A, Cycle B & Cycle C.
Cycle A is based upon test CCT-4. Please see elsewhere in this document for details of CCT-4. This test method has been shown to correlate well with natural exposure for thermosetting paints. The number of cycle repeats is to be sufficient for 1000 hours total test time, unless otherwise agreed.
Cycle B is based upon test VDA 621-415. Please see elsewhere in this document for details of VDA 621-415. This test method has been shown to correlate well with natural exposure for thermosetting paints in vehicle corrosion. The number of cycle repeats is to be sufficient for 840 hours total test time, unless otherwise agreed.
Cycle C has been developed in the UK for use with water soluble and latex paint systems, and has been shown to correlate well with natural exposure. Cycle C test specimens are placed in an enclosed chamber and exposed to a changing climate that comprises of the following repeating cycle. 210 minutes exposure hours exposure to a continuous indirect spray of salt water solution, which falls-out on to the specimens at a rate of 2.0 to 4.0ml/80cm²/hour, in a chamber temperature of +25C. This is followed by 210 minutes exposure to an air drying climate at +40C (humidity unspecified). This is followed by 1470 minutes exposure to a controlled humidity climate of 75%RH at +40C. This is followed by 102 minutes exposure to an air drying climate at +25C (humidity unspecified). This is followed by 210 minutes exposure to a salt fog climate at +25C. This is followed by 378 minutes exposure to a condensing water climate of 95 to 100%RH at +30C. This is followed by 180 minutes exposure to an air drying climate at +35C (humidity unspecified). This is followed by 120 minutes exposure to an air drying climate at +25C (humidity unspecified). The number of cycle repeats is to be sufficient for 1000 hours total test time, unless otherwise agreed.
Chamber volumes of less than 400 Litres are not permitted by this test standard.
