scope:

This part of ISO 8502 describes a method for the determination of chloride-containing salts that are readily soluble in water and are present on a steel surface. The method is also applicable to previously coated surfaces. It will normally be used in a laboratory using washings sampled from surfaces on site. The method is applicable to the determination of salts that have been deposited on the steel surface before, during or after the cleaning operations. The test method is not applicable to surfaces treated with chromate, nitrite or amine, which are commonly used as inhibitors in the water when wet blast-cleaning. This is because a chromate concentration of 10 mg/l or greater or a nitrite concentration of 20 mg/l or greater in the wash water interferes with the determination of the chloride. Also the amine inhibitors can form a hydroxide boundary layer (not water soluble) over the substrate and prevent the water from contacting the underlying salt for its removal. An iron(III) ion concentration of 10 mg/l also interferes with the determination, but the iron(III) ions are concentrated in the rust deposits, which are removed from the test solution by filtration.