Preparing the Surface of a Storage Tank: Contamination and Testing


There are many factors that can improve a tank’s life cycle and durability. The tank coating, in particular, can serve as a defense against corrosion and reduce the risk of contamination. The decision about the coating process can also impact other factors of tank fabrication, like size, capacity, cost, turnaround time, and ease of construction.

Surface Preparation

When a tank is manufactured, uncoated steel can form a layer of corrosion. Manufacturers need to have this layer removed before any type of coating can occur. Preparation can occur by blasting the surface with grit. This can eliminate surface corrosion and toughen the steel surface to allow for a better grip. When well-conducted, uniform grit blast coverage is applied to all areas of the tank to ensure maximum coating adhesion.

Environmental Contamination

After a tank surface is prepared, it is vulnerable to environmental contamination. Flash rust can develop in as little as half an hour of exposure. In order to avoid this problem and maintain the quality of a tank, coating should be applied as soon as the surface is prepared. The time between surface preparation and paint application can affected the tank’s expected field longevity.

The adhesion of the coating surface can also be affected by environmental contamination in the form of airborne particles. Manufacturers can avoid these particles by applying strict quality control measures, like that of proper cleaning and filtering of equipment. These processes and maintenance practices can prevent airborne particles from interfering and affecting the coating’s adhesion to the tank.

Testing Applied Coatings

Incremental tests should be conducted during a factory-applied coating process. Test parameters should include paint booth temperature, wash water temperature and pH, humidity, and air quality. The entire coating process should be closely monitored to ensure they remain up to specific standards.

Installing high-tech coating lines can also ensure the efficiency and accuracy of the coating process. They can facilitate air particulate monitoring, overspray capture, and the precise measurement of coating quality and thickness.

Place of Application

Large water storage

The application of tank coating can occur in a factory or in the field itself. Surface preparation is a regular part of coating applications for factory-coated tanks. On the other hand, tanks coated in the field require inspection before any kind of application can be performed. This includes a review of the undersides of the tank’s floor and roof.

Factory Application

The fusion of glass to steel requires molecular interaction to ensure both materials cannot be separated from each other. This type of fusion is only possible with factory, and not field applications.

Field Application

In the field, tanks usually have to be sand blasted and coated with epoxy. It is more difficult to monitor and control the entry of air particles with these types of applications as they are exposed to greater degrees of environmental contamination and subject to harsher temperature and humidity conditions.

Tanks with field-applied coating require repainting and maintenance sooner than those with factory-applied coating. When a tank is well-fabricated and has a strong coating application, the tank becomes a longer lasting and more durable storage solution.

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