An important factor to consider when applying a coating for storage tank lining, before any product is even sprayed, is the preparation of the steel. When applying solvent-free coatings this is especially important.

For a coating to perform to expectations and avoid premature failure, then preparation needs to be correct. If preparation is poor the performance of the coating will be poor.

Preparing the surface

Blasting is by far the best method of surface preparation. It provides an excellent foundation for coating application.

Blasting the steel creates a good profile, essentially roughening the surface. Creating a sharp, angular profile allows for better coating adhesion and anchoring. This helps prevent delamination of the coating from the substrate. Blasting is typically done to SA2.5 standard.

This also removes any corrosion and contaminants, such as oil, grease and salts, that may be present on the internal steel. Again, creating a better surface upon which to spray any coatings. Any corrosion damage to the steel will now be evident. Any UT thickness checks or repairs that need to be done can be carried out at this point.

Steel surface after blast clean

Steel surface after blast clean

The most common type of storage tank corrosion

We often find heavy pitting in storage tanks. The extent of which is only clear to see once they’ve been blast cleaned. This kind of pitting corrosion often leads to some very serious problems in the storage tank.

Pitting corrosion is a localised form of corrosion which causes small pits to form in the metal. If left untreated this type of corrosion will lead to a breach in the tank and leaking product.

It’s important that this type of corrosion doesn’t go untreated. A well-applied coating which is resistant to the stored product and completely encapsulates the internal steel of the storage tank is the best way to do this. You can find out more about pitting corrosion here.

Detail of pitting corrosion inside storage tank

Pitting corrosion found in a storage tank

Making sure the profile is correct

We like to make sure we have the profile we need before our trained applicators begin spraying the solvent-free products we use. We do this with a blast inspection verification. A specialised instrument measures the profile of the blast. It does this by measuring the peak-to-valley ratio. This measurement is important to ensure we are achieving the required specification.

Blast verification checks to blast profile

Verification checks to blast profile

When we achieve the required blast profile only then will the application of the solvent-free coating take place.

We aim to provide our clients with a long-lasting solution to storage tank corrosion. One that meets their expectations and provides increased longevity for the storage tank.

There’s an old saying that rings true “if a job’s worth doing it’s worth doing right”. This 100% applies to storage tank lining, and good preparation is key to achieving this.