DIFFERENCE BETWEEN API 650 AND API 620 TANKS API 650 vs API 620 API 650 AND API 620 TANKS API 650 TANKS API 650 is widely used for tanks that are designed to internal pressures of 2.5 PSI or less and store products such as crude oil, gasoline, chemicals and produced water. API 650 tanks ranging in diameter from 8' - 300' API 620 TANKS These storage tanks operate at 250°F or less with an operating pressure of up to 15 PSI. API 620 Tanks are generally utilized for Liquefied Natural Gas (LNG) storage as well as other chemicals API 650 Configuration API 620 Configuration ThankYou