Surge vessels with broken down coatings

THE PROBLEM

The existing coatings had broken down and been identified as a risk item for both water hygiene and if left unchecked the structural integrity of the pressure vessel.

As part of the remedial tank lining works all of the existing coatings had to be removed to allow the full inspection of the surge vessel internals for insurance purposes.

The vessels were in a dust sensitive environment that the client did not want contaminated with dust from the preparation works.


SOLUTION

We proposed the removal of the existing tank linings by method of low dust sponge blasting prior to the application of a Acothane DW as specified.

Initially the tanks were prepared using Spongejet Sponge blasting technology.  By using this low dust blasting technology and a small extractor the dust from the removal of the existing tank linings was easily contained. More information on how this technology works can be seen in the video.

Ensuring adhesion of the new lining

Once prepared the surface profile was checked using a surface profile needle gauge to ensure compliance with the manufacturers recommendations and ensure excellent adhesion of the new tank linings.

The tanks were vacuumed and a surface cleanliness test was conducted, as similarly this is important to ensure the correct adhesion of the new tank lining. If the new tank lining is being applied to a layer of contamination it will not adhere correct.

Applying the stripe coats

As per best tank lining practice separate stripe coats were applied at each stage of the tank lining process to ensure full film build on angles and edges where paint pulls thin through surface tension and gravity. By applying additional stripe coats in these areas the correct tank lining thickness is achieved.

Upon application of the final coat the dry film thickness was checked and recorded. Any areas below the required thickness were made good.

Finally a DC holiday spark test was conducted to check for pin holing and porosity. Where found these were similarly touched in by brush.

Surge vessels in place after relining
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