Which type of load is NOT considered by API 650 in tank design?

• A. Thermal effects
• B. Human factor loads
• C. Wind loads
• D. Seismic loads

Answer: (B)

API 650 primarily focuses on the design of welded tanks for oil storage, taking into account various environmental and operational loads that can affect the integrity and stability of these tanks. Among the types of loads considered, thermal effects, wind loads, and seismic loads are explicitly addressed due to their impact on the structural performance of the tanks.

Thermal effects are important because temperature variations can lead to expansion and contraction of the tank materials. Wind loads are considered critical for ensuring the tank can withstand forces caused by wind pressure. Seismic loads are also significant, particularly in areas prone to earthquakes, as they evaluate the tank's ability to endure ground motion without failure.

In contrast, human factor loads are not a specific consideration in the API 650 guidelines. While human activities and operations can influence tank management and maintenance, they do not contribute to the structural design loads that API 650 addresses. This makes human factor loads the type that is not considered in the design criteria outlined in API 650.