Test of Paints for Water Tank Interiors

In 1950, the Steel Structures Painting Council (SSPC), the Ambridge Water Authority, and the Pittsburgh‐ Des Moines Steel Co., all located in the Pittsburgh area, cooperated in undertaking an extensive test of paints for use on the interior of water tanks. The purpose of this test was to evaluate the relative performance of several of the most serviceable conventional paint systems applied to surfaces that had been blast cleaned. Also evaluated were several of the vinyl paints available at that time. A 1‐mil gal open‐topped steel tank, 84 ft. in diameter and 25 ft high, was selected as the test site. It is located about 20 mi north of Pittsburgh, at Ambridge, Pennsylvania. The inside of the tank was divided into 54 panels. Each of the panels received a system consisting of some combination made up from twelve paint systems, two pretreatments, and ten methods of surface preparation. Pretreatment consisted of either a vinyl washcoat or a phosphoric acid treatment. In all instances, the panels were blast cleaned and the pretreatment or primer applied before any detrimental rusting could occur. The article discusses test preparation, along with results and conclusions.