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 and 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-Cycle D

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.

Cycle D is based upon the requirements of JIS K 5621 – 2003 test specimens are placed in an enclosed chamber and exposed to a changing climate that comprises of the following repeating cycle. 30 Minutes of salt spray @ 30C (+/-2C) followed by wetting for 90 minutes @ 30C (+/-2C) & 95%RH (+/-3%), followed by drying @ 50C (+/-2C) for 120 minutes, and drying @ 30c (+-/2C) for 120 minutes.  The following transition times apply

  • 10 minutes from salt spray to wetting
  • 15 minutes from wetting to hot drying
  • 30 minutes from hot drying to warm drying
  • instantaneous from warm drying to salt spray

Total cycle time is 6 hours, unless otherwise agreed Cycle D repeats for 28 cycles (168h)

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.

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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.