Why Soluble Salts Matter

Chlorides, sulfates and other soluble contaminants can remain in pits or on the surface after visible rust and coating are removed. Under a new film they may contribute to osmotic blistering or accelerated corrosion.

When Testing Is Considered

Testing is commonly evaluated for marine exposure, immersion service, previously contaminated steel, severe corrosion, chemical facilities and critical lining work. The owner specification determines whether testing is required and the allowable level.

Sampling Must Represent the Asset

Locations should account for horizontal surfaces, pits, splash zones, runoff paths, lower elevations and known contamination. One convenient test point may not represent an entire tank, structure or vessel.

Cleaning and Retesting

If results exceed the project limit, the approved cleaning method may include potable-water washing, pressure washing or other specified treatment. The area is then allowed to reach acceptable conditions and is retested before coating.

Avoid Recontamination

Cleaned steel should be protected from dirty water, contaminated abrasive, bare-hand contact, dust and environmental exposure. Timing between cleaning, preparation, testing and coating must be coordinated.

Keep Traceable Records

Document the test method, instrument or kit, lot information where applicable, location, surface condition, result, corrective action and retest acceptance.