Ascott Corrosion Test Chambers

Corrosion Testing Standards

The test standard summaries are for general guidance only. Though believed to be accurate at the time of writing, this may change over time. So this information should not be used as a substitute for referring to a complete test standard, at an appropriate revision level.
Note: the terms salt spray, salt mist & salt fog are all in wide spread use within corrosion test standards. In this context they can be considered to be equivalent and interchangeable terms.

ISO11997-1

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.

These tests are also referred to as a Cyclic Corrosion Tests, often abbreviated to CCT.

For further information on ISO standards visit; www.iso.org

Note; many ISO test standards have been harmonized with other European standards and these are now prefixed ‘EN’ (Euro Norm) or ‘** EN’ – where ** are the letters representing a European country/language code, for example ‘BS EN’ for a harmonized British standard in English language.

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