Preparation of steel substrates before application of paints and related products -- Tests for the assessment of surface cleanliness -- Part 2: Laboratory determination of chloride on cleaned surfaces
This standard has been revised by ISO 8502-2:2017
ISO 8502-2:2005 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.
ISO 8502-2:2005 is applicable to the determination of salts that have been deposited on the steel surface before, during or after the cleaning operations.
ISO 8502-2:2005 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.