A COST- AND SAFETY-CONSCIOUS APPROACH TO COATING TANK EXTERIORS

Paul Cook, of Painters USA, examines best practices for facility and terminal managers Surveys and testing are vital for delivering safety, savings and long-lasting surface coatings, regardless of where a tank is located. Here’s an example: A facility manager invited a certified NACE Institute inspector and instructor into his facility to quote a project for sandblasting and coating a tank. As the inspector examined the tank, which contained sulfuric acid, he noticed a few, almost imperceptible, spots flaking off. The tank’s top revealed slight areas where the steel had swelled (Figure 1). The inspector immediately asked if anyone had inspected the tank via ultrasonic testing (UT) to detect and pinpoint discontinuities and get a measurement of the tank’s wall thickness. It is critical to use UT to check steel welds and metal thickness – a contractor can only blast so much. The inspector next asked if the facility manager had conducted testing for salt (e.g. chloride, sulphate, nitrate). Abrasive blasting can force salts into new areas of a tank’s surface and coating, which then draws in moisture and undermines a new coating. The inspector ultimately found a high level...