Which statement accurately reflects the vapor dome tank capacity?

• A. Varies with construction
• B. Capacity is fixed at 2,000,000 gallons
• C. A max of 8,500,000 gallons
• D. Capacity is always under 1,000,000 gallons

Answer: (C)

Vapor dome tanks are designed with a fixed maximum capacity to ensure the structure can safely contain liquid while providing enough vapor space for boil-off and thermal expansion. The design limits—rooted in the dome’s geometry, shell strength, foundation and safety margins—establish an upper bound on how much liquid can be stored. For this type of tank, that upper bound is 8,500,000 gallons, so describing a maximum of eight and a half million gallons accurately reflects the real-world constraint. Other options imply either a small fixed size, no ceiling, or capacity that varies without bound, which doesn’t align with the engineered limit that governs these tanks.