Kesternich tests

The Kesternich test according to ISO 3231 (or ASTM G87) is a cyclic condensation test in an acidic environment. In the closed test chamber where the samples are exposed, an atmosphere of 100% relative humidity at a temperature of 40 °C is maintained during the first 8 hours of a 24-hour period, to which a specific amount of SO2 (sulfur dioxide) is added at the start. After these 8 hours, the chamber is vented, the heating is turned off, and the samples remain at room temperature and ambient relative humidity for the next 16 hours. Following this, the condensation/temperature/SO2 atmosphere is re-established, and the test cycle repeats for the next 24 hours. This process continues until the required number of cycles is reached. This can vary from 2 to 50 or more.

The Kesternich test is found in various standards and specifications, such as Qualicoat for powder-coated aluminum, Qualisteelcoat, specifications for bolts and screws, as well as in various specifications for coil coating systems and coatings for automobiles and traffic objects.

Variants of the test are also performed in the Kesternich chamber involving the injection of other gases (for example, CO2 or NH3) and the maintenance of different temperatures.