A client had designed and fabricated two types of above-ground tanks, originally intended to be in accordance with API 650. Due to time limitations and unavailability of 304 stainless steel, the tank material was changed to A-240 LDX 2101. However, this material is partly austenitic and partly ferritic, and not listed in in the API 650. Therefore, OCE performed finite element analyses on both tanks. It was determined that one of the tanks would not maintain integrity when operating under maximum operating conditions, thus reinforcements were designed for the tank.