What is the capacity of the vapor dome roof tank?

• A. A maximum of 6,000,000 gallons
• B. 5,000,000 gallons
• C. 8,000,000 gallons
• D. A max of 8,500,000 gallons

Answer: (D)

A tank’s capacity is limited by its physical dimensions and the roof design that closes off the vapor space. With a vapor dome roof, the dome defines how much liquid can be safely stored because the liquid level must stay below the dome to maintain proper venting and pressure control. For this specific design, the geometry of the tank and the dome results in a maximum liquid capacity of 8,500,000 gallons. That’s the upper limit set by the size and shape of the tank and its vapor dome. The other numbers would indicate smaller tanks or different configurations, but they don’t reflect the maximum capacity for this particular vapor dome roof tank.