The Bresle method is used to determine concentration of soluble salts on metal surfaces prior to coating application, such as painting.
With spray from waves and by other means, salt gets into the air as an aerosol, and eventually as a dust-like particle.
The test was developed to measure soluble salt concentration on steel surfaces prior to blasting cleaning and coating.
Not only ISO, but also the US Navy, IMO, NAVSEA, and ASTM adopted this method as their standard.
When performing a Bresle method test, not only sodium chloride is dissolved but also all other salts present on the surface.
Because it is impossible to predict which salts are present at the surface, an assumption is made in the Bresle method.
All parties involved should be clear on the impact on results of climate and the variance of the potentially different salt contents.
This annex describes a stress test to ensure patch adhesion and wash ability.
A soluble salts report should include climate conditions and substrate temperature.
ISO 8502-6 requires that the test is done at 23 °C and a relative humidity of 50%, with deviations reported and agreed upon by both inspector and customer.