The level of protection from gradual destruction of materials, (usually metals), by chemical reaction with its environment. The salt spray test is a standardized test method used to check corrosion resistance of coated samples—testing procedure and testing parameters are standardized under national and international standards, such as ASTM B 117. These standards describe the necessary information to carry out this test, such as temperature, air pressure of the sprayed solution, preparation of the spraying solution, concentration, pH, etc.